rexresearch
Frederick MACDONNEL, et al.
Synfuel Production
http://phys.org/news/2016-02-proven-one-step-co2-liquid-hydrocarbon.html#jCp
February 22, 2016
Proven one-step process to convert CO2 and water directly into liquid hydrocarbon fuel

A team of University of Texas at Arlington chemists and engineers have proven that concentrated light, heat and high pressures can drive the one-step conversion of carbon dioxide and water directly into useable liquid hydrocarbon fuels.
This simple and inexpensive new sustainable fuels technology could potentially help limit global warming by removing carbon dioxide from the atmosphere to make fuel. The process also reverts oxygen back into the system as a byproduct of the reaction, with a clear positive environmental impact, researchers said.
"Our process also has an important advantage over battery or gaseous-hydrogen powered vehicle technologies as many of the hydrocarbon products from our reaction are exactly what we use in cars, trucks and planes, so there would be no need to change the current fuel distribution system," said Frederick MacDonnell, UTA interim chair of chemistry and biochemistry and co-principal investigator of the project.
In an article published today in the Proceedings of the National Academy of Sciences titled "Solar photothermochemical alkane reverse combustion," the researchers demonstrate that the one-step conversion of carbon dioxide and water into liquid hydrocarbons and oxygen can be achieved in a photothermochemical flow reactor operating at 180 to 200 C and pressures up to 6 atmospheres.
"We are the first to use both light and heat to synthesize liquid hydrocarbons in a single stage reactor from carbon dioxide and water," said Brian Dennis, UTA professor of mechanical and aerospace engineering and co-principal investigator of the project.
"Concentrated light drives the photochemical reaction, which generates high-energy intermediates and heat to drive thermochemical carbon-chain-forming reactions, thus producing hydrocarbons in a single-step process."
Duane Dimos, UTA vice president for research commended the researchers on their success.
"Discovering a one-step process to generate renewable hydrocarbon fuels from carbon dioxide and water is a huge achievement," Dimos said. "This work strengthens UTA's reputation as a leading research institution in the area of Global Environmental Impact, as laid out in our Strategic Plan 2020."
The hybrid photochemical and thermochemical catalyst used for the experiment was based on titanium dioxide, a white powder that cannot absorb the entire visible light spectrum.
"Our next step is to develop a photo-catalyst better matched to the solar spectrum," MacDonnell said. "Then we could more effectively use the entire spectrum of incident light to work towards the overall goal of a sustainable solar liquid fuel."
The authors envision using parabolic mirrors to concentrate sunlight on the catalyst bed, providing both heat and photo-excitation for the reaction. Excess heat could even be used to drive related operations for a solar fuels facility, including product separations and water purification.
The research was supported by grants from the National Science Foundation and the Robert A. Welch Foundation. Wilaiwan Chanmanee, postdoctoral research associate in mechanical and aerospace engineering, and Mohammad Fakrul Islam, graduate research assistant and Ph.D. candidate in the department of Chemistry and Biochemistry at UTA, also participated in the project.
MacDonnell and Dennis have received more than $2.6 million in grants and corporate funding for sustainable energy projects over the last four years.
MacDonnell and Dennis' investigations also are focused on converting natural gas for use as high-grade diesel and jet fuel. The researchers developed the gas-to-liquid technology in collaboration with an industrial partner in UTA's Center for Renewable Energy and Science Technology, or CREST, lab, and are now working to commercialize the process.
MacDonnell also has worked on developing new photocatalysts for hydrogen generation, with the goal of creating an artificial photosynthetic system which uses solar energy to split water molecules into hydrogen and oxygen. The hydrogen could then be used as a clean fuel.

http://www.pnas.org/content/early/2016/02/17/1516945113
Solar photothermochemical alkane reverse combustion
Wilaiwan Chanmanee, Mohammad Fakrul Islam, Brian H. Dennis, and Frederick M. MacDonnell

Significance
An efficient solar process for the one-step conversion of CO2 and H2O to C5+ liquid hydrocarbons and O2 would revolutionize how solar fuel replacements for gasoline, jet, and diesel solar fuels could be produced and could lead to a carbon-neutral fuel cycle. We demonstrate that this reaction is possible in a single-step process by operating the photocatalytic reaction at elevated temperatures and pressures. The process uses cheap and earth-abundant catalytic materials, and the unusual operating conditions expand the range of materials that can be developed as photocatalysts. Whereas the efficiency of the current system is not commercially viable, it is far from optimized and it opens a promising new path by which such solar processes may be realized.
Abstract
A one-step, gas-phase photothermocatalytic process for the synthesis of hydrocarbons, including liquid alkanes, aromatics, and oxygenates, with carbon numbers (Cn) up to C13, from CO2 and water is demonstrated in a flow photoreactor operating at elevated temperatures (180–200 °C) and pressures (1–6 bar) using a 5% cobalt on TiO2 catalyst and under UV irradiation. A parametric study of temperature, pressure, and partial pressure ratio revealed that temperatures in excess of 160 °C are needed to obtain the higher Cn products in quantity and that the product distribution shifts toward higher Cn products with increasing pressure. In the best run so far, over 13% by mass of the products were C5+ hydrocarbons and some of these, i.e., octane, are drop-in replacements for existing liquid hydrocarbons fuels. Dioxygen was detected in yields ranging between 64% and 150%. In principle, this tandem photochemical–thermochemical process, fitted with a photocatalyst better matched to the solar spectrum, could provide a cheap and direct method to produce liquid hydrocarbons from CO2 and water via a solar process which uses concentrated sunlight for both photochemical excitation to generate high-energy intermediates and heat to drive important thermochemical carbon-chain-forming reactions.

WO2015109217
 TANDEM PHOTOCHEMICAL-THERMOCHEMICAL PROCESS FOR HYDROCARBON PRODUCTION FROM CARBON DIOXIDE FEEDSTOCK

Inventor(s):     MACDONNEL FREDERICK [US]; DENNIS BRIAN [US]; CHANMANEE WILAIWAN [US] +
Applicant(s):     UNIV TEXAS
The present invention is directed at an improved process for generating heavier hydrocarbons from carbon dioxide and/or carbon monoxide and water using tandem photochemical-thermochemical catalysis in a single reactor. Catalysts of the present disclosure can comprise photoactive material and deposits of conductive material interspersed on the surface thereof. The conductive material can comprise Fischer-Tropsch type catalysts.
DESCRIPTION
[0001] This application claims priority to United States Provisional Application No.: 61/928,719 filed January 17, 2014. The entire text the above -referenced disclosure is specifically incorporated herein by reference without disclaimer.
BACKGROUND OF THE INVENTION

A. Field of the Invention
[0002] The invention generally concerns thermal, photocatalytic processes and systems that can be used to produce hydrocarbons from water and Ci feedstocks, e.g., CO and/or C02.
B. Description of Related Art
[0003] Recycling C02 to produce hydrocarbons, particularly long chain hydrocarbons, in a commercially viable manner has long been a goal of scientific research. Such a process could produce a chemical fuel and assist in curbing the effect of climate change.
[0004] In order to achieve commercial viability, the energy required must be provided from a renewable source. One source that holds particular promise is the sun. Solar light energy provides a seemingly infinite source of energy. Thus, harvesting the energy of solar light and its subsequent storage in the form of chemical fuels hold promise to address the current and future demand of energy supply.
[0005] Despite nearly 40 years of research on the photocatalytic reduction of C02, the scientific community is still a long way from efficient and commercially viable devices. Presently, yields are too low to be viable and predominantly produce methane. The highest rates of product formation generally do not exceed tens of μιηοΐ of product per hour of illumination per gram of photocatalyst. Habisreutinger et al., "Photocatalytic Reduction of C02 on Ti02 and Other Semiconductors," 52 Agnew. Chem. Int. Ed. 7372, 7373 (2013). Longer chain hydrocarbons are produced at even lower concentrations. See e.g. , Varghese et al., "High-Rate Solar Photocatalytic Conversion of C02 and Water Vapor to Hydrocarbon Fuels," Nano Letters, vol. 9, no. 2, 2009, at p. 734.
SUMMARY OF THE INVENTION
[0006] The present application is directed to compositions, devices, systems, and methods that generate heavier hydrocarbons (i.e., hydrocarbons having >2 carbons) by way of coupling the photo-oxidation of water and the photo-reduction of CO or C02 with thermal- chemical carbon-chain formation. The energy for which can be largely if not entirely provided by the sun through the use of concentrated solar radiation. Harnessing the sun's energy for the photochemical excitation of a photoactive material as well as the heat needed to favor carbon-chain formation reactions make the described processes energy efficient.
[0007] In particular, the present application involves a continuous gas phase process for the photochemical water oxidation under conditions that favor the transfer of the associated electrons and/or protons to drive the reduction of C02 or CO and the conversion of the reduced CO or C02 products to longer carbon-chain products. Some of these conversion reactions involve Fischer-Tropsch processes that are thermal and pressure driven processes. In addition, the presence of alkylbenzene products suggests that surface bound alkynes are also formed and cyclotrimerize as another method of forming higher carbon number hydrocarbons.
[0008] One aspect of the disclosure relates to a solid catalyst comprising a photoactive material support having a surface and a conductive material interspersed on the surface of the support. In various embodiment, the conductive material comprises a metal, e.g., at least one of Co, Fe, and Ru. In various embodiments, the photoactive material support comprises titanium dioxide. In various embodiments, the conductive material is Co. In various embodiments, the catalyst further comprises a hygroscopic additive. For example, the hygroscopic additive can be a salt comprising at least one of the following anions: P04<3">, HP04<2">, H2P04<">, S04<2">, HS04<">, C03<2> , OH<">, F<">, CI<">, Br<"> and I<"> and at least one of the following cations: Li<+>, Na<+>, K<+>, Rb<+>, Cs<+>, Be<2+>, Mg<2+>, Ca<2+>, Sr<2+>, Ba<2+> and Al<3+>. In various embodiments, the hygroscopic additive comprises an acid and wherein the acid comprises at least one of the following: H2S04, H3P04, HF, HC1, HBr, and HI. In various embodiments, the hygroscopic additive is disposed on the surface of the photoactive material support. In various embodiments, the catalyst further comprises a redox-active additive. In various embodiments, the redox-active additive comprises a salt comprising at least one of the following cations: Mn<2+>, Mn<3+>, Mn<4+>, Fe<2+>, Fe<3+>, Co<2+>, Co<3+>, Ni<2+> and at least one of the following anions: P04<3">, HP04<2">, H2P04<">, S04<2">, HS04<">, C03<2> , OH<">, F<">, CI<">, Br<"> and I<">. In various embodiments, the redox-active additive is disposed on the surface of the photoactive material support. In various embodiments, the solid catalyst is a plurality of nanoparticles. In various embodiments, the solid catalyst is coated on a substrate. In various embodiments, the substrate is a surface of a pellet, wherein the pellet is optically transparent. In various embodiments, the pellet is thermally conductive.
[0009] A further aspect of the disclosure comprise an apparatus for carrying out thermocatalytic and photocatalytic reactions comprising a reaction vessel having a vessel wall defining a chamber and having a gas inlet and a gas outlet in fluid communication with the chamber, the reaction vessel configured to operate at temperatures greater than 100°C and to permit electromagnetic radiation to pass through at least a section of the vessel wall and into the chamber and a catalytic body comprising a surface and disposed in the chamber, where disposed on the surface of the catalytic body is the above described solid catalyst. [0010] Relatedly, another aspect relates to a method of coupling photochemical water oxidation with C02 or CO reduction and thermochemical carbon-chain formation comprising providing a flow of water and at least one of C02 and CO into a reaction chamber containing a supported metal catalyst in accordance with the present disclosure; heating the reaction chamber to a reaction temperature greater than 100°C; and exposing the supported metal catalyst to electromagnetic radiation, thereby causing photochemical water oxidation, C02 or CO reduction, and thermochemical hydrocarbon formation, wherein the hydrocarbons comprise alkanes and alcohols having at least 2 carbons.
[0011] Similarly, another aspect of the disclosure relates to a method of converting a gaseous mixture comprising C02 and water to hydrocarbons, the method comprising: providing a flow of water and at least one of CO and C02 into a reaction chamber containing a supported metal catalyst; heating the reaction chamber to a reaction temperature greater than 100°C; and exposing the supported metal catalyst to electromagnetic radiation, thereby causing a reaction that generates hydrocarbons from the provided flow, wherein the supported metal catalyst comprises a photoactive material support and a plurality of conductive particles disposed on the support. In various embodiments, the reaction temperature is between 100°C and 300°C. In various embodiments, the reaction temperature is between 150°C and 250°C. In various embodiments, heating the reaction chamber comprises directing sunlight reflecting from a solar concentrator onto the reaction chamber. In various embodiments, the photoactive material support is a semiconductor support and the supported metal catalyst is the semiconductor support having a surface with metal particles interspersed on the surface. In various embodiments, the method further comprises collecting the hydrocarbons. In various embodiments, collecting the hydrocarbons comprises passing outflow from the reaction chamber through a separation device comprising at least one of a condensation column, an adsorbent material, membrane, or centrifuge. In various embodiments, the method further comprises recycling the outflow from the separation device into the reaction chamber. In various embodiments, the hydrocarbons include alkanes or alcohols having at least 2 carbons. In various embodiments, the hydrocarbons include alkanes or alcohols having at least 6 carbons. In various embodiments, the hydrocarbons include at least one of methane, ethane, propane, butane, hexane, heptane, septane, octane, nonane, decane, methanol, ethanol, propanol, butanol, acetone, acetic acid, and alkylbenzene derivatives and oxygenates thereof. In various embodiments, the supported metal catalyst is adapted to absorb electromagnetic radiation having wavelength between 200 nm and 700 nm, between 200 nm and 600 nm, between 200 nm and 500 nm, or between 200 nm and 400 nm.
[0012] Another aspect of the disclosure relates to an apparatus for carrying out thermocatalytic and photocatalytic reactions can comprise a reaction vessel having a vessel wall defining a chamber and having a gas inlet and a gas outlet in fluid communication with the chamber, a packed bed comprising a surface and disposed in the chamber, where disposed on the surface of the packed bed is a supported metal catalyst comprising a photoactive material support and a conductive material interspersed on the support; and a gaseous mixture consisting essentially of water and at least one of CO and C02 within the chamber at a temperature greater than 100°C. The reaction vessel is configured to operate at temperatures greater than 100°C and to permit electromagnetic radiation to pass through at least a section of the vessel wall and into the chamber.
[0013] Yet another aspect of the disclosure relates to a solar concentrating system comprising an optical concentrating device and a packed bed reactor configured to receive light from the optical concentrating device; a gasification unit in fluid communication with the reaction chamber configured to convert liquid water to steam; and a C02 supply line in fluid communication with the reaction chamber. The reactor can comprise a reaction vessel having a vessel wall defining a chamber and having a gas inlet having an inflow and a gas outlet having an outflow, both being in fluid communication with the chamber. The reaction vessel can be configured to operate at temperatures greater than 100°C and to permit electromagnetic radiation to pass through at least a section of the vessel wall and into the chamber to a packed bed comprising a surface. Disposed on the surface of the packed bed is a supported metal catalyst comprising a photoactive material support and a conductive material interspersed on the support. In various embodiments, the system further comprises a separation unit for extracting hydrocarbons from the outflow. In various embodiments, the system further comprises a gas mixer to mix the steam with carbon dioxide. In various embodiments, the system further comprises a heat exchanger configured to transfer thermal energy from the reaction vessel to the gasification unit.
[0014] Yet another aspect of the disclosure relates to a method for concentrating solar radiation to provide light for the photochemical excitation of a supported metal catalyst and to provide the thermal energy needed for carbon-chain formation reactions, the method comprising: providing a flow of water and at least one of C02 and CO into a reaction chamber containing a supported metal catalyst comprising a semiconductor, wherein the pressure in the reaction chamber is between 1 atm and 15 atm; and concentrating and directing solar radiation to the reaction chamber, thereby heating the reaction chamber to a reaction temperature greater than 100°C and causing the photochemical excitation of the semiconductor, wherein hydrocarbons having at least 2 carbons are formed in the reaction chamber. In various embodiments, the supported metal catalyst is a solid catalyst in accordance with the present disclosure. In various embodiments, the flow further comprises water vapor. In various embodiments, some heat from the reaction chamber is transferred to a vaporization unit containing water.
[0015] The term "intersperse" is defined as a random or patterned distribution of substantially discrete things, e.g., particles, on the surface of and/or within a medium.
[0016] The term "coupled" is defined as connected, although not necessarily directly, and not necessarily mechanically.
[0017] The terms "a" and "an" are defined as one or more unless this disclosure explicitly requires otherwise.
[0018] The preposition "between," when used to define a range of values (e.g., between x and y) means that the range includes the end points (e.g., x and y) of the given range and of course, the values between the end points.
[0019] The term "substantially" is defined as being largely but not necessarily wholly what is specified (and include wholly what is specified) as understood by one of ordinary skill in the art. In any disclosed embodiment, the term "substantially" may be substituted with "within [a percentage] of what is specified, where the percentage includes 0.1, 1, 5, and 10 percent.
[0020] The terms "comprise" (and any form of comprise, such as "comprises" and "comprising"), "have" (and any form of have, such as "has" and "having"), "include" (and any form of include, such as "includes" and "including") and "contain" (and any form of contain, such as "contains" and "containing") are open-ended linking verbs. As a result, the particles, devices, methods, and systems of the present invention that "comprises," "has," "includes" or "contains" one or more elements possesses those one or more elements, but is not limited to possessing only those one or more elements. Likewise, an element of a particle, device, method, or system of the present invention that "comprises," "has," "includes" or "contains" one or more features possesses those one or more features, but is not limited to possessing only those one or more features.
[0021] Furthermore, a structure that is capable performing a function or that is configured in a certain way is capable or configured in at least that way, but may also be capable or configured in ways that are not listed.
[0022] The feature or features of one embodiment may be applied to other embodiments, even though not described or illustrated, unless expressly prohibited by this disclosure or the nature of the embodiments. [0023] Any composition, device, method, or system of the present invention can consist of or consist essentially of— rather than comprise/include/contain/have— any of the described elements and/or features and/or steps. Thus, in any of the claims, the term "consisting of or "consisting essentially of can be substituted for any of the open-ended linking verbs recited above, in order to change the scope of a given claim from what it would otherwise be using the open-ended linking verb.
[0024] Details associated with the embodiments described above and others are presented below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] The following drawings illustrate by way of example and not limitation. For the sake of brevity and clarity, every feature of a given structure may not be labeled in every figure in which that structure appears. Identical reference numbers do not necessarily indicate an identical structure. Rather, the same reference number may be used to indicate a similar feature or a feature with similar functionality, as may non-identical reference numbers.
[0026] FIG. 1 illustrates a schematic example of the photo-induced formation of an electron-hole pair of the photoactive catalyst composite facilitating the oxidation and reduction reactions. "A" represents an electron acceptor and "D" represents an electron donor.
[0027] FIG. 2A illustrates a schematic of photoactive catalyst composite in accordance with the present disclosure.
[0028] FIG. 2B illustrates a schematic of a photoactive catalyst composite disposed on a substrate composite in accordance with the present disclosure.
[0029] FIG. 3A illustrates a schematic of a reactor in accordance with the present disclosure.
[0030] FIG. 3B illustrates a schematic of a reactor in accordance with the present disclosure. [0031] FIG. 4 A illustrates a schematic of a system for converting Ci feedstock and water into hydrocarbons.
[0032] FIG. 4B illustrates an array of solar concentrators and reaction vessels in accordance with the present disclosure.
 

DETAILED DESCRIPTION OF THE INVENTION
[0033] Various features and advantageous details are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. It should be understood, however, that the detailed description and the specific examples, while indicating embodiments of the invention, are given by way of illustration only, and not by way of limitation. Various substitutions, modifications, additions, and/or rearrangements will become apparent to those of ordinary skill in the art from this disclosure.
[0034] In the following description, numerous specific details are provided to provide a thorough understanding of the disclosed embodiments. One of ordinary skill in the relevant art will recognize, however, that the invention may be practiced without one or more of the specific details, or with other systems, methods, components, materials, and so forth. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the invention.
[0035] The present invention is predicated upon the unexpected realization of a substantially improved process and system for generating heavier hydrocarbons from a Ci feedstock and water according to a process that generates the required activation energies mostly if not entirely from sunlight. While not wishing to be bound by any particular theory, the present invention is directed at an improved process for generating heavier hydrocarbons from CI feedstock and water using photocatalytic and Fischer-Tropsch type processes in a single reactor. The improved process can generate heavier hydrocarbons with the use of renewable energy sources. (It should be realized, however, the invention contemplates the optional use of features that provide energy from nonrenewable sources.) Among the advantages, hydrocarbons can be produced at yields greater than 100 μg/g of catalyst per hour and even greater than 200 μg/g of catalyst per hour. In addition, the percentage of heavier hydrocarbons is greater than the percentage of methane and/or methanol.
[0036] As described in detail below, the present disclosure contemplates that one or more photochemical reactions and thermal reactions take place in tandem, preferably within a single reaction chamber or single zone within a reaction vessel. Moreover, the photochemical reactions take place at the relatively high temperatures and/or the relatively high pressures needed to facilitate the thermal reactions that produce heavier hydrocarbons at yields greater than 3 μιηοΐ/g of catalyst per hour. Preferably, the reaction chamber is maintained so that the Ci feedstock and water therein are at a temperature greater than or equal to 100°C, and more preferably higher than 120°C. The reaction chamber may exhaust into a recovery unit wherein the generated hydrocarbons are extracted from the exhausted gas stream, and a return path from the recovery unit may couple to the reaction chamber to form a closed loop system, as described herein.
[0037] The catalyst of the present disclosure is a composite material preferably in the form of particles that are sufficiently small to be characterized as nanoparticles (e.g., they have an average diameter less than about 100 nm). The catalyst composite comprises a photoactive material and a conductive species (e.g., a supported metal catalyst) on which (not wishing to be bound by a particular theory) water oxidation, Ci feedstock reduction, and Fischer-Tropsch type reactions are believed to occur causing a gaseous mixture of Ci feedstock and water, exposed to both sunlight and thermal energy, to generate hydrocarbons, a majority portion of which are heavier hydrocarbons. Ci feedstock are simple carbon- containing substrates that contain one carbon atom per molecule and include, e.g., methane, carbon dioxide, carbon monoxide, and methanol. In various embodiments, the gas stream comprises Ci feedstock that is substantially CO and C02. In various embodiments, the gas stream comprises Ci feedstock that is substantially CO or C02.
A. Photoactive Catalysts
[0038] In accordance with the present disclosure, the photoactive catalysts can comprise a photoactive material and a conductive species disposed or interspersed on at least a portion of the surface of the photoactive material. With respect to the photoactive material, it can comprise any material that provides suitable band gap excitations (e.g., semiconductive materials). With respect to the conductive species, it can comprise any material that accepts the photo-generated electrons and facilitates transporting such electrons to the surface for participation in the reduction process and carbon-chain formation. In various embodiments, the photoactive catalyst is a supported metal catalyst. [0039] While not wishing to be bound by a particularly theory, with reference to FIG.
1, in various embodiments, the semiconductor(s) is selected to have a band gap that spans the range of the reduction and oxidation potentials relevant to the photo-catalyzed reactions, namely the oxidation of water (>0.82 V vs NHE at pH 7.0) (1) and the reduction of Ci feedstock (<-0.41 V vs NHE at pH 7.0) (2), the later predominantly occurring on the conductive material deposits. For example, the band gap of titanium dioxide is 3.0 and 3.2 eV for rutile and anatase, respectively, and thus, only radiation shorter than 400 nm is absorbed, which is not very matched with the majority of the solar spectrum reaching the earth's surface. The valence band edges for rutile and anatase are well in excess of 0.82 V and the conduction band edge is approximately -0.40 V) In certain embodiments, other semiconductor(s) are selected so that the photoactive catalyst absorbs a wide spectrum of solar radiation. For example, BiV04 is a semiconducting metal oxide which absorbs light at wavelengths less than 550 nm and which could be used as a photoactive support for the metal co-catalyst to drive the desired reaction utilizing a greater portion of the solar spectrum. In certain embodiments, the supported metal catalyst is adapted to absorb electromagnetic radiation having wavelength less than 700 nm, less than 600 nm, or less than 500 nm.
[0040] Combined with the semiconductive material, conductive materials can comprise a material, such as a metal or metal oxide, that facilitates transporting the photo- generated electrons from the semiconductive material to the surface for reduction of Ci feedstock (2) and subsequent carbon-chain formation (3). While not wishing to be bound by any particular theory, it is believed that the semiconductor serves as the photo-anode, oxidizing water and transferring electrons and protons to the conductive material islands. Presumably, these form surface hydrides that are the reducing agents for Ci reduction and subsequent carbon-chain formation reaction.
[0041] The oxidation and reduction reactions are summarized below with an example of reaction conditions. With the use of the described photoactive catalyst and methods of the present disclosure, reactions (l)-(3) can take place in a single reactor.
hv (<400 nm)
2 H20 02 + 4 H<+> + 4 e (1 )
- 200 C, 15-300 psi
C02 + 2 H<+> + 2 e<"> CO + H20
Co
_ - 200 C, 15-300 3⁄4si
n CO + 4n H<+> + 4n e l2n+2 + + n H20 (3)
Co
It is noted, particularly where the CI feedstock includes CO, a series of thermochemical reactions are possible (e.g., reverse water-gas shift chemistry coupled with Fischer-Tropsch chemistry), and could also yield hydrocarbons. To the extent such reactions are occurring, it would be in addition to the coupled photo-thermochemical process described above.
[0042] Semi-conductive materials can comprise metal oxides, preferably Ti02. The
Ti02 can be in any form such as anatase or rutile. Other examples of semi-conductive materials include CdS, TaON, ZnO, and BiV04.
[0043] In some embodiments, the semi-conductive material is a nanoparticle. The nanoparticle can comprise any shape. The term nanoparticles, refers to a particle having an average width of less than about 200 nm. These nanoparticles may be spherical or close to spherical in shape. Nanoparticles can have a smooth surface or a rough surface, e.g., a highly varied surface with cracks, pits, pores, undulations, or the like to increase the overall surface area. Nanoparticles that are in the form of nanowires, nanotubes, or irregular shaped particles may also be used. Nanoparticles, such as nanotubes, can have a low wall thickness that facilitates transfer of photo-generated charge carriers to the conductive species. If the particles do not have a spherical shape, the size of the particles can be characterized by the diameter of a generally corresponding sphere having the same total volume as the particle. In some embodiments, the nanoparticles have an average diameter of at least 5 nm. In some embodiments, the nanoparticles have an average diameter of less than about 50 nm and even less than about 20 nm.
[0044] In various embodiments, the conductive material comprises any material suitable as a catalyst in the Fischer-Tropsch reaction. In some embodiments, the conductive material comprises or consists essentially of a metal or metal oxides of the metal selected from the following group: Fe, Co, Ni, Cu, Ru, Rh, Ir, Pd, Pt and Ag or any combination thereof. In some embodiments, the conductive material comprises Co and/or C02O3. In certain embodiments, the conductive material is at least 90%, 91%, 92%, 93%, 94%, 95%, 96%o, 97%), 98%o, or 99% C02O3. In various embodiments, the conductive material comprises a plurality of small particles, such as metal crystallites or nanoparticles. As schematically illustrated in FIGS. 2 A to 2B, the conductive material 152 can be surface decorated or wet- impregnated onto the semi-conductive material 154 such that conductive particles or deposits 152 are disposed or interspersed on the semi-conductive surface 154, referred to together as a metal supported catalyst 150. The % weight of conductive material relative to the semi- conductive material can be any amount between 1% to 30%>, such as about 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%), 24%), 25%), 26%), 27%, 28%, 29%, or any value or range there between. In some embodiments, the % weight of the conductive material relative to the semi-conductive material is between about 2% to about 15%. [0045] In some embodiments, the semi-conductive material can comprise a combination of semi-conductive materials and one or more dopants to enhance the efficiency of the catalyst through extension of the absorption range and/or improvement in the charge separation to increase the number of photo-excited electrons and decrease the number that return to the valence band. For example, Ti02 can be doped with nitrogen, such as nitrogen in the form of ammonium flouride. The % weight of the dopant relative to the semi- conductive material can be any amount between 0% to 5%, such as between about 1% and 3%.
[0046] Alternatively or in addition thereto, a hygroscopic additive can be applied or added to the semiconductor to aid in the stabilization or formation of a surface hydration layer to enhance proton transport during active catalysis. For example, depositing hygroscopic salts or acids onto the semiconductor particles can favor hydration under the process conditions described herein and support proton transport from the sites of water oxidation on the semiconductor surface to the conductor material deposits. Examples of hydroscopic salts include the various salts and acidic salts that can form from combining at least one of the following anions: P04<3">, HP04<2">, H2P04<">, S04<2">, HS04<">, C03<2> , OH<"> , F<">, CI<">,
I _|_ _|_ _|_ _|_ 2"!" 2 I
Br<">, or Γ, with at least one of the following cations: Li , Na , K , Rb , Cs , Be , Mg , Ca , Sr<2+>, Ba<2+>, or Al<3+>. Examples of acids include H2S04, H3P04, HF, HC1, HBr and HI. The % weight of the hygroscopic additive relative to the semi-conductive material can be any amount between 0% and 5%, preferably 1% and 3%.
[0047] Alternatively or in addition thereto, a redox-active additive could be applied or added to the semiconductor to enhance water oxidation. For example, depositing a redox- active transition-metal salt onto the semiconductor particles can facilitate or enhance the water oxidation process. Examples of the redox active transition metal salts include the various salts that can form from combining at least one of the following cations: Mn<2+>, Mn<3+>, Mn<4+>, Fe<2+>, Fe<3+>, Co<2+>, Co<3+>, Ni<2+>, Ru<2+>, Ru<3+>, Ru<4+>, Rh<+>, Rh<2+>, Rh<3+>, Ir<+>, Ir<2+>, and Ir<3+> and at least one of the following anions: P04<3">, HP04<2">, H2P04<">, S04<2">, HS04<">, C03<2">, O<2">, OH<">, F<">, CI<">, Br<"> and Γ. The % weight of the redox-active additive relative to the semi-conductive material can be any amount between 0% and 5%, such as between 1% and 3%.
[0048] Alternatively or in addition thereto, a supported metal catalyst can be further modified by addition of a basic metal oxide promotor of the Fischer-Tropsch synthesis reaction. For example, the basic metal oxide promotor can comprise an oxide salt comprising at least one of the following cations: Sc , Y , La , Ce , Pr , Nd<3+>,Sm<3+>,Eu<3+>,Gd<3+>,Tb<3+>,Dy<3+>,Ho<3+>,Er<3+>,Tm<3+>,Yb<3+>, Ac<3+>, Th<3+>, Pa<3+>, and U<3+>. The % weight of the basic metal oxide promotor relative to the semi-conductive material can be any amount between 0% and 5%, such as between 0.5% and 3%.
[0049] In various embodiments, metal supported catalyst 150 is deposited on the surface of a substrate-providing member 140, referred to together as a catalyst body 130. Substrate-providing member 140 can be a molded or extruded body. The surface can be smooth or porous. Substrate-providing member 140 can comprise any suitable material able to withstand the process temperatures and be substantially inert. In various embodiments, the catalyst comprises water soluble components, but is still adapted to withstand the reactant gases and not be significantly dissolved during use. In various embodiments, the material is substantially transparent to visible and ultraviolet light at least within the absorption range of semiconductor. In some embodiment, the material can absorb the infrared radiation received from the sunlight or from the ongoing reaction to facilitate maintaining the high reaction temperatures the reaction chamber, as described below. Examples of material of which substrate-providing member 140 can be composed include glass, quartz, or any other solid UV transmitting medium that is solid at process temperatures, such as temperatures up to 250°C.
[0050] Substrate providing member 140 can be any shape for optimizing the surface area upon which catalyst composite 150 is disposed to receive electromagnetic radiation. For example, substrate member 140 can define any shape, e.g., a planar, spherical, ovoidal, elliptical, prismoidal, polyhedron, or pyramidal body. In some embodiments, the catalyst composite 150 can be coated on bead(s), pellet(s), or the like. In other embodiments, catalyst composite 150 can be coated on a body having a generally planar or corrugated surface, such as a fin(s) radially extending out from a central core or a cylindrical body having an outer surface comprising a plurality of undulating or otherwise protruding features to form a corrugated surface. In yet other embodiments, substrate-providing member can comprise three-dimensional substantially porous body or web-like body that provides a substrate and allows sunlight to pass through its full depth. [0051] In addition, substrate providing member 140 can be of any suitable size. For example, when in the shape of a bead, pellet, or particle, substrate providing member 140 can have a minimum width of greater than approximately 1 mm, and can have a maximum width of less than approximately 20 mm. In some embodiments, substrate providing member 140 is substantially spherical, and has a diameter in the range of approximately 1 mm to 10 mm, such as 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, or 9 mm. In other embodiments, when substrate providing member provides a generally planar or corrugated surface or is a porous or web-like body, the dimensions can be such that substrate member 140 extends the length and width of a reaction chamber discussed herein.
[0052] The catalyst body 130 can further comprise a medium within which the metal supported catalyst 150 are dispersed. The medium can allow catalyst 150 to adhere to a substrate. In addition, the medium can facilitate surface redox reactions and improve the efficiency of catalyst 150. For example, a medium can comprise an ionomer, e.g., a perfluorosulfonic acid (H<+> form)/polytetrafluoroethylene copolymer (Nafion<®>). Other suitable mediums include QPAC (poly(alkylene carbonate)), QPAC 25 (PEC, polyethylene carbonate), QPAC 40 (PPC, polypropylene carbonate), polyvinyl alcohol (PVA), polystyrene-b-poly(ethylene oxide) (PS-b-PEO) polymers, and the like. Other ionomers or guidelines for selecting or designing an ionomer may be found in the following article: Viswanathan & Helen, "Is Nafion, the only choice?", Bulletin of the Catalysis Society of India, 6 (2007) 50-66, which is hereby incorporated by reference in its entirety. The % weight of a medium relative to the semi-conductive material can be any amount between 0% and 10%, such as 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, or 9%.
B. Photoactive Catalytic Reactor

[0053] With reference to FIG. 3 A, another aspect of the present disclosure comprises an apparatus for carrying out the thermochemical and photochemical reactions. In particular, the reactor 200 comprises a reaction vessel 210 having a vessel wall 212 defining a reaction chamber 214 and having one or more gas inlet(s) 216 configured for gaseous inflow of water and Ci feedstock and a gas outlet 218 configured for gas outflow comprising hydrocarbons, both of which are in fluid communication with chamber 214. In some embodiments, a plurality of catalyst bodies 230 can sufficiently fill reaction chamber 214 to form a "packed bed." In other embodiments, a catalytic body can comprise a corrugated surface or a porous or web-like body coated with the described catalyst. Reaction vessel 210 can further comprise a filter (not shown) at gas outlet 218 to prevent escape of catalyst bodies 130.

[0054] During use, the reaction vessel 210 can be exposed to solar radiation and heated at or above the boiling temperature of water to convert the gaseous mixture of water and Ci feedstock into hydrocarbons including alkanes or alcohols having at least 2 carbons. Examples of the hydrocarbons that can be formed include methane, ethane, propane, butane, pentane, hexane, septane, octane, nonane, decane, methanol, ethanol, propanol, isopropanol, butanol, hexanol, acetic acid, acetone, alkyl benzene and oxygenates thereof, as well as longer alkanes, alcohols, and/or organic acids, or mixtures thereof. In some embodiments, reactor 200 can generate hydrocarbons having at least 2 carbons at a rate of at least 50 μg/g of catalyst per hour, 60 μg/g of catalyst per hour, 70 μg/g of catalyst per hour, 80 μg/g of catalyst per hour, 90 μg/g of catalyst per hour, 100 μg/g of catalyst per hour, 150 μg/g of catalyst per hour, 200 μg/g of catalyst per hour, 250 μg/g of catalyst per hour, 300 μg/g of catalyst per hour, 350 μg/g of catalyst per hour, or more. For example, as can be discerned from Table 3 in Example 4 below, a reactor in accordance with the present disclosure was shown to generate hydrocarbons having at least 2 carbons at a rate of approximately 87 g/g of catalyst per hour (at 2.7 atm and 0.6 Pw/C), and when including CO, methane and methanol in this calculation, the productivity value of the catalyst is even greater, such as at 121 μg/g of catalyst per hour.

[0055] In some embodiments, the process conditions of the reactor can be adapted to generate one or more alkybenzene derivatives including toluene (C7H7), ethylbenzene (CgHio), propylbenzene (C9H12), ortho-, meta-, and para-xylenes (CgHio), ortho-, meta-, and para-methylethylbenzene (C9H12), ortho-, meta-, and para-methylpropylbenzene (C10H14), ortho-, meta-, and para-diethylbenzene (C10H14) as well as thier oxygenates. For example, the process conditions can comprise a Pw/C between 0.2 and 1 , such as 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, or 0.3. In various embodiments, the process conditions are adapted such that alkyne cyclotrimerization reactions occur in the reactor in addition to the Fischer-Tropsch reactions.
[0056] Reaction vessel 210 is configured to operate at temperatures greater than 100°C and to permit electromagnetic radiation, e.g., sun light, to pass through at least a section of vessel wall 212 and into chamber 214 where a plurality of catalytic bodies 130 are disposed. For example, vessel wall 212 can be composed of a substantially transparent material that is substantially heat tolerant and substantially UV tolerant material. In addition, in some embodiments, vessel wall 212 material may be required to withstand higher pressures, e.g., absolute pressures between 1 atm to 20 atm or any range therebetween. In some embodiments, vessel wall 212 can have a thickness less than about 10mm, 5mm, 4mm, 3mm, 2mm, 1mm, or any amount therebetween. In some embodiments, vessel wall 212 comprises any material through which radiation, such as sunlight, can pass through, and that can maintain high tensile strength at process temperatures, such as, temperatures up to 250°C, e.g., quartz, glass, (such as tempered glass and borosilicate glass), or the like.
[0057] One or more of walls 212 of the reaction vessel 210 or a portion thereof may be formed of transparent material. It is also possible that most or all of the walls 212 of reaction vessel 210 are transparent such that light may enter from many directions. For example, with reference to FIG. 3B, reaction vessel 210 may be a glass cylinder that is surrounded by an trough-like solar concentrator 206 that reflects light back into the reaction vessel. In another embodiment, reactor vessel 210 may have one side that is transparent to allow the incident radiation to enter and the other sides may have a reflective interior surface that reflects the majority of the solar radiation.
[0058] Reaction vessel 210 can be configured to operate at ambient operating pressures. Other embodiments, reaction vessel 210 can be configured to operate at much higher pressures to improve or vary hydrocarbon yields as appropriate. For example, operating pressures can be up to 30 atm. In some embodiments, reaction vessel 210 is configured to maintain an operating pressure of between about 1.0 atm and about 15 atm, or a smaller range therebetween. For example, operating pressures can be about 1 atm, 2 atm, 3 atm, 4 atm, 5 atm, 6 atm, 7 atm, 8 atm, 9 atm, 10 atm, 1 1 atm, 12 atm, 13 atm, and 14 atm, 15 atm, 16 atm, 17 atm, 18 atm, 19 atm, 20 atm, 21 atm, 22 atm, 23 atm, 24 atm, 25, atm, 26, atm, 27 atm, 28 atm, or 29 atm. [0059] In some embodiments, reactor 200 can be heated largely if not entirely by solar energy. For example, again with reference to FIG. 3B, reactor 200 can be configured to receive solar radiation from a solar concentrator 206. Solar concentrator 206 comprises a reflective surface configured to direct solar radiation to reactor 200 and can be used to heat reactor 200 to a reaction temperature of 100°C, 1 10°C, 120°C, 130°C, 140°C, 150°C, 160°C, 165°C, 170°C, 175°C, 180°C, 185°C, 190°C, 195°C, 200°C, 205°C, 210°C, 215°C, 220°C, 225°C, 230°C, 240°C, 250°C, 260°C, 270°C, 280°C, 290°C, 300°C, or any range thereof or value therebetween. In the same or different embodiments, reactor 200 can be heated by a heater 270 to the desired reaction temperature. In some embodiments, reactor 200 may comprise radially extending conductive fins to distribute heat in reactor 200. Reactor 200 may also comprise a thermocouple 222 to monitor the temperature. Heater 270 can be used to regulate the reaction temperature as needed.
[0060] In some embodiments, heat from reactor 200 can be used to change water in liquid form to vapor form in a vaporization unit, further described below. As such, a heat exchanger (not shown) containing a heat transfer fluid can be disposed within reactor 200 to absorb some of the thermal energy provided by the sun or from the ongoing redox reactions and a conduit can transport the heated transfer fluid to the vaporization unit also comprising a heat exchanger to transfer the heat from the fluid to the water in the vaporization unit to convert the water feedstock to vapor. Moreover, heat transfer fluid can be used to facilitate regulation of the reaction temperature within reaction chamber 214. [0061] With reference to FIG. 4A, another aspect of the present invention comprises a system in which the above described reactor 200 is incorporated to generate hydrocarbons and separate the generated hydrocarbons from the gas outflow. A system can also comprise the described reactor 200 comprising an array of reaction vessels 210, as shown in FIG. 4B.
[0062] In order to convert a gaseous mixture of Ci feedstock and water to hydrocarbons, gaseous feedstock of Ci feedstock and water flows into the reaction chamber of reactor 200 containing the described catalyst. In some embodiments, the molar flow ratio of the water to Ci feedstock is between 0.1 to 10.0, and such as between 0.1 and 3.0 or 0.1 and 4.0. In some embodiments, within the reaction chamber, the partial pressure ratio of water to CI feedstock (Pw/c) can be maintained approximately at a value between 0.1 to 3, such as 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.4, 1.6, 1.8, 2.0, 2,2, 2.4, 2.6, 2.8, or any value or range therebetween. The reaction chamber can be heated to or maintained at a desired reaction temperature and configured such that the described catalyst is exposed to solar radiation while the gaseous feedstock mixture is flowing there-through, thereby causing reactions that generate hydrocarbons from the Ci feedstock and water.
[0063] When providing a flow of reactants into reactor 200, Ci feedstock and the water in vapor form can flow into the reaction chamber as a mixture or as discrete inflows. System 300 can comprise a supply conduit 301 for providing Ci feedstock. Ci supply conduit 301 can merge with the water vapor supply conduit 302 to mix the two components at the desired ratios. In some embodiments, system 300 can comprise a gas proportioner or mixer 303 to facilitate mixing the gaseous components at the desired ratio. In some embodiments, the flow rate of each can be adjusted to control the relative ratio of the two components.
[0064] In order to provide water in vapor form, system 300 can also comprise a vaporization unit 304 configured to convert liquid water to steam. The steam generated flows from vaporization unit 304 into water vapor supply conduit 302. In some embodiments, vaporization unit 304 can comprise a heat exchanger through which a heat transfer fluid can flow. In some embodiments, the heat transfer fluid can flow from reactor 200 through the heat exchanger via conduit loop 307 to heat a surrounding bath of water. In the same or different embodiments, vaporization unit 304 can comprise, a mister, a humidifier, such as a evaporative humidifier, a natural humidifier, an impeller humidifier, a ultrasonic humidifier or a forced air humidifier, a vaporizer, or any other suitable device. In some embodiments, vaporization unit 304 also operates as a mixer or proportioner 303 such that Ci feedstock can flow into vaporization unit 304 and mix with water vapor.
[0065] In order to extract the generated hydrocarbons, system 300 can further comprise separation device 305 for extracting a substantial portion of the hydrocarbons from the gaseous outflow. For example, separation device 305 can comprise at least one of a condensation column, membrane, centrifuge, an adsorbent material, or some combination thereof. While not shown in the figure, it is understood that in certain embodiments, once the hydrocarbons are extracted, the gaseous outflow may be recycled back to reactor 200. [0066] In order to reduce or substantially remove unwanted products from the outflow, system 300 can further comprise another separation device (not shown). For example, dioxygen can be separated by passing the outflow through the separation device, such as at least one of a condensation column, an adsorbent material, membrane, or centrifuge. This separation device can intercept the outflow before or after it passes through to separation device 305. Once removed, in certain embodiments, the outflow can be recycled from the separation device into the reaction chamber.
[0067] To facilitate heating reaction chamber and to enhance the efficiency of the described catalyst, system 300 can comprise a solar concentrator 206 comprising a reflective surface(s) that directs sunlight to one or more reaction vessels 210. As shown in FIG. 4B, a system can also comprise a plurality of solar concentrators 206 and a plurality of reaction vessels 210. Reaction vessels 210 can be in fluid communication with each other or isolated therefrom. Reaction vessels can be configured so that the outflow from each flows into a single separation device 305. [0068] In some embodiments, heating the reaction chamber can be caused by directing solar radiation from solar concentrator 306 to the reaction chamber. Alternatively or in addition thereto, a heater can be used to heat the reaction chamber. In addition, a heat exchanger can be located in reaction chamber facilitating the transfer of heat from chamber to a heat transfer fluid or vice versa. D. EXAMPLES
[0069] The present invention will be described in greater detail by way of specific examples. The following examples are offered for illustrative purposes only, and are not intended to limit the invention in any manner. Those of skill in the art will readily recognize a variety of noncritical parameters that can be changed or modified to yield essentially the same results.
EXAMPLE 1
PREPARATION OF TITANIUM DIOXIDE/COBALT CATALYST

[0070] Titanium dioxide-cobalt catalyst were prepared by incipient wetness impregnation of Ti02 (rutile) with sufficient aqueous solution of C0NO3 (Alfa Aesar) to give a loading of 5 % by mass cobalt when dried, calcined, and reduced. The impregnated Ti02 was dried at room temperature for overnight and calcinations under air at 225°C for 3 h and then sieved using No 100 (opening 0.15 mm). The dried catalyst was reduced at 400°C in a flow of H2 for 8 h. XPS spectroscopy indicated that only 1% of the cobalt present was in the metallic state, the remainder was present as C02O3.
EXAMPLE 2
PREPARATION OF THE CATALYST ON A SUBSTRATE
[0071] The catalysis supports were Pyrex glass pellets having a 2 mm diameter.
Before Co-Ti02 catalyst was immobilized on the Pyrex glass pellets, these glass pellets were etched in 5M NaOH solution for 24 h at 70°C. After they had been rinsed with DI water, the glass pellets were soaked in an aqueous suspension, which was prepared with 3 g of catalyst as prepared in Example 1 and dispersed in 3.0 mL of DI water with the aid of an ultrasonic bath to which 3.0 mL of 5% w/w Nafion PTFE was added. After removing from the Catalyst-PTFE solution, the glass pellets were heated at 70°C in a vacuum oven. The resulting pellets were opaque with a dull gray powder thinly coated on the surface.
EXAMPLE 3
PREPARATION OF PACKED-BED THERMOPHOTOCATALYTIC REACTOR
[0072] A quartz tube having a length of 10 in. and a diameter of 1.4375 in. and a wall thickness of 1/8 in. and two plastic caps that fit on each end of the tube comprised the catalytic chamber. A stainless steel tube with an inner diameter of 0.25 in. and a length of 10 in. was placed along the center of the center of the quartz tube, and a cartridge heater was placed inside the stainless steel tube. The quartz tube was filled with the catalytic pellets as prepared in Example 2. Three holes were drilled on one of the caps and one hole was drilled in the other. Graphite tape, metal camps, and high temperature PTFE O-rings were placed between the caps and the tube to provide the necessary seal. A thermocouple was inserted into one hole, the cartridge heater was inserted through a central hole, and a fitting for the inflow gas line was placed in the third. A fitting for the outflow gas line was placed in the hole of the other cap. The C02 gas was regulated by a digital flow meter and directed into a water saturation unit that humidified the gas. The cartridge heater was controlled by a discrete feedback controller to maintain the desired reaction temperature as measured by the thermocouple. The quartz tube was surrounded by four Hg UV producing lamps with a total power of 850W. A schematic is shown in FIG. 4. EXAMPLE 4
CONVERSION OF CARBON DIOXIDE AND WATER INTO HYDROCARBONS USING THE CATALYST
[0073] The system as described in Example 3 was used to study catalyst performance and carbon products produced under various process conditions.
[0074] In a first study, the reaction was run under 1 atmosphere pressure for 8 hours.
Carbon dioxide flowed into the saturator having 20 mL of water to mix the carbon dioxide with water vapor. The temperature of the saturator was set to produce the desired flow rate of water vapor. The input of carbon dioxide was set at the desired flow rate of 50 mL/min at 0 psig. The water flow rate was 0.03 mL/min. This corresponds to a CC^fLO molar ratio of 1 :3. Many runs were conducted at six different reactor temperatures: 110°C, 130°C, 150°C, 180°C, 200°C , and 220°C. Two phase of Ti02 were tried, rutile and anatase.
[0075] Liquid aliquots were collected and tested on a Shimadzu GC-MS-2010SE chromatograph coupled with a MS QP2010 detector and a AOC-4 20S sampler. The column was a Shimadzu SHRX105MS (30-m length and 0.25-mm inner diameter, part # 220-94764- 02) set at 45°C for 5 minutes then increased to 150°C at a rate of 10°C/min. The MS detector was set at 250°C, and helium was used as the carrier gas. A l μΐ^ sample of the liquid aliquot was injected into the GC-MS. The results are provided in Table 1 below.
[0076] Table 1. Effect of temperature and Ti02 phase on products at 1 arm pressure and Pw/c = 0.6.
<img class="EMIRef" id="316689023-imgf000021_0001" />
12 TiO2(anatase)-150 2.70 - 1.20 - 4.7E-4
13 TiO2(anatase)-180 - 5.5 4.2 16.2 7.3E-4
14 TiO2(anatase)-200 - 130 92.4 90.6 3.6E-3
[0077] A second study was also conducted in a similar manner with the set up as described in Example 3. A titanium dioxide-cobalt catalyst was prepared by wet impregnation as described in Example 1 , except that the anatase form of Ti02 was used for this study.
[0078] For the runs conducted, carbon dioxide flowed into the saturator having 20 mL of water to mix the carbon dioxide with water vapor. The temperature of the saturator was set to produce the desired flow rate of water vapor. The input of carbon dioxide was set at the desired flow rate of 50 mL/min at 0 psig. The water flow rate was 0.03 mL/min. This corresponds to a C02:H20 molar ratio of 1 :3. The reaction temperature, the reaction pressure, and the partial pressure ratios of the reactants, water and C02 were varied for purposes of this study.
[0079] For most runs, to determine the amount and type of products in the gaseous effluent, the effluent was passed through an online-reactor gas analyzer by Custom Solutions Group (CSG), Houston, TX. The gas analyzed is built on a Shimadzu Model GC-2014 and equipped with a split/splitless injection port, a three channel automated pressure control and auto flow control, and TCD and FID detectors. The instrument was precalibrated by CSG for analysis of light to medium hydrocarbons and their oxygenates, CO, C02, 02, H2, and N2.
[0080] The permutations of pressure, temperature, and partial pressure ratio that were studied are summarized in Tables 2 and 3 alongside the results of those runs. Each run was conducted for 8 hours. Results for the runs conducted at 200 C are provided in Tables 3 and 4.
[0081] Table 2. Effect of temperature, pressure, and the partial pressure ratio on product make-up
<img class="EMIRef" id="316689023-imgf000022_0001" />
<img class="EMIRef" id="316689023-imgf000023_0001" />
[0082] As gleaned from the results in Table 2, methanol was observed at the lower temperatures (i.e., 110 to 150 C), but higher Cn products (>C1) began to appear at temperatures of 180 C or higher, predominantly as iso-propanol (Run 4), and increased upon going to 200 C (Run 5) and 220 C (Run 6) with an apparent yield maximum at 200 C. Lowering the Pw/C from 1.2 to 0.6 resulted in an increase in the number of products obtained to include ethanol, acetic acid, isopropanol, and acetone (Run 7). The most striking result was obtained with the application of 2.7 atm of pressure at 200 C (Pw/C =0.6) as seen in Run 11. Now in addition to the CI -3 products, hydrocarbons with Cn of 4, 6, 8, 9 and 10 were also obtained, with the last three (C8-10) being pure hydrocarbons. Control reactions have established that light, Ti02, Co, C02, and elevated temperature (180-200 C) are all required.
[0083] In specific runs, isotopically labelled reactants, 30% enriched <13>C02 (Run 8) or 99 % enriched D20 (Run 9) or were used to establish that H20 and C02 where the sources for hydrogen and carbon in the products, respectively. In both cases, the organic products showed the expected incorporation of the label as determined by GC-MS (see supporting information). The 13-carbon label appearing in the relative amount expected statistically for a 30% enriched feedstock. Deuterium incorporation was lower than expected for a 99 % enriched feedstock but still the dominant isotope of hydrogen found in the product (i.e. the formation of products such as
<img class="EMIRef" id="316689023-imgf000024_0001" />
The non-statistical level of H over D incorporation is likely due to kinetic isotope effects, and the presence of surface bound H20 in the reactor and catalyst despite an initial purge with C02.
[0084] Table 3. Effect of pressure and water/C02 partial pressure ratio (Pw/C) on product yield at 200 C.
H2 2.4 4.1 8.4 17.2 5.5 9.8 2.4 4.1 8.4 17.2 5.5 9.8
C2+ 16.9 14.8 87.2 11.8 62.0 63.0 4.6 3.8 21.2 3.9 16.5 13.8
Cl-4 61.9 60.6 116.6 40.4 102.3 113.8 8.2 7.4 22.1 6.2 13.1 17.9
C5+ 0.0 0.0 4.8 0.0 31.1 0.2 0.0 0.0 1.9 0.0 8.3 0.1
Sum 81.3 79.6 217.0 69.3 201.0 186.8 10.6 11.5 32.4 23.3 26.9 27.8
02 Yld(%) 535 229 73 75 107 138
IPQY(%) 0.06 0.07 0.19 0.13 0.15 0.16
[0085] Table 4. Product Distribution by Carbon Number (Cn), Total Pressure and Partial Pressure Ratio of Water to C02.
<img class="EMIRef" id="316689023-imgf000025_0001" />
<img class="EMIRef" id="316689023-imgf000025_0002" />
[0086] In this second study, product carbon number (Cn) distribution and incident photon quantum yields (IPQYs) show a strong dependence on the reaction pressure, temperature, irradiation levels, and the PH2o / Pco2 ratio (Pw/C), suggesting that the photochemical steps are not rate determining here. For example, at 200 C, an increase in pressure from 1 atm to 6.1 atm increased the average productivity increased from 80 to 200 μg/gh (units: μg fuel/gcataiysth), respectively, an overall increase of 250 % and shifts the product distribution to higher molecular weight products. The products and mass yields obtained in this latter run (200C, 6.1 atm, Pw/c 0.6) are H2 (6.5%), CO (25.5%), CH4 (0.7 %), CH3OH (0.1%), C2H4 (1.3%), C2H6 (1.2%), H3C202H (34.2%), C3H8 (0.9%), C3H7OH (0.2%), C4H8 (3.7%), C4HioO (21.9%), C8Hi0 (0.4%), and C9Hi2 (3.3, of which 64% are liquid products.
[0087] 02 was also isolated in a 2 to 5-fold stoichiometric excess compared to the reduced product obtained at 1 atm. At higher pressures, the 02 yield was either near stoichiometric (~75 % for the runs at 2.6 atm) or only present in modest excess (107-138% for the runs at 6.1 atm). As the products should be present stoichiometrically, these data suggest we have not accounted for all the reduction products in certain runs. For runs at 1 atm, these are likely to be high boiling point oxygenates adsorbed onto the catalyst or surface of the reactor, especially near the exit zone at which the temperature drops considerably. At 6.1 atm, the missing product could be either oxygenates like above or heavy hydrocarbons which condense in the exit zone or transport tubes. Lastly, dioxygen plus both components of syngas, CO and H2, are observed as co-products in the studied reactor, so it seems reasonable that a water splitting reaction and a reverse water gas shift reaction are functional, but it may be that most of the H2 and CO are not released from the cobalt surface.
[0088] The presence of an excess or near stoichiometric amount of 02 suggests that the back reaction, 02 oxidation of H2 or hydrocarbon products, is somewhat inhibited, most likely due to the low 02 concentration, estimated to be between 4% and 0.4% v/v in any given run. One explanation for the large excess of 02 seen at 1 atm, but not at 2.6 or 6.1 atm, is that the space velocity is faster at lower pressures, meaning the 02 is swept from the reaction chamber more quickly and has less time to participate in the back reaction. As such, mass flow rates and space velocity can be adjusted to remove 02 more quickly from the reactor so it can be separated from the flow.
[0089] As mentioned, CO and H2 are both observed as products, yet both are reactants for the Fischer-Tropsch reaction. Also mentioned, the data suggests that not all of the CO or H2 equivalents (i.e. surface cobalt hydrides) are released in the gas phase but instead are generated on the surface of the cobalt islands and consumed immediately in subsequent chain-forming reactions. The reasoning here is similar to the poor 02 back reaction rates, even with 100 % release into the gas phase, the resulting low partial pressures of CO and H2 would make it very unlikely that a chain-forming reaction mechanism could be sustained. In some embodiments, these flow with these products and can be recycled into the reactor chamber to further favor C02 reduction and Fischer-Tropsch type reactions.
[0090] The presence of alyklbenzene products reveals that one of the chain-forming reactions is likely proceeding via the formation of alkyl alkynes and subsequent alkyne trimerization. While higher hydrogen yields may be anticipated with more water, the better selectivity towards higher Cn products at Pw/C of 0.6 is, in part, a reflection of an unusual synthetic pathway that appears to be operational at this lower water partial pressure. All of the products with Cn>6 are all identified as variously substituted alkylbenzenes or oxygenates thereof, which is atypical of traditional FTS product distributions.
[0091] Currently, the highest IPQY obtained is 0.19% on a per electron stored basis
(or 0.105% on a H2 equivalent basis), but this is a reflection of the early stage of this work rather than any practical limitation. There is a significant (2 to 3 -fold) jump in ICPY upon increasing the pressure from 1 atm to 2.6 atm, but little further change upon increasing the pressure to 6.1 atm. In theory, quantum yields of 30-50%) at 200 C are possible and if the Ti02 could be replaced by a semiconductor absorber that covered more of the visible spectrum (i.e. <700 nm), then overall solar to fuel (STF) conversion efficiencies of 5-15% are reasonable goals. However, the process in the study is not optimized and these initial studies indicate that higher yields and/or higher order hydrocarbons are accessible at higher pressures, higher temperatures, and other Pw/c ratios.
[0092] The above specification and examples provide a complete description of the structure and use of an exemplary embodiment. Although certain embodiments have been described above with a certain degree of particularity, or with reference to one or more individual embodiments, those skilled in the art could make numerous alterations to the disclosed embodiments without departing from the scope of this invention. As such, the illustrative embodiments of the present photothermocatalytic compositions, reactors, systems, and process are not intended to be limited to the particular forms disclosed. Rather, they include all modifications and alternatives falling within the scope of the claims, and embodiments other than the one shown may include some or all of the features of the depicted embodiment. For example, components may be combined as a unitary structure and/or connections may be substituted. Further, where appropriate, aspects of any of the examples described above may be combined with aspects of any of the other examples described to form further examples having comparable or different properties and addressing the same or different problems. Similarly, it will be understood that the benefits and advantages described above may relate to one embodiment or may relate to several embodiments.

US2016040072
 PROCESSES FOR LIQUEFYING CARBONACEOUS FEEDSTOCKS AND RELATED COMPOSITIONS

Inventor(s):     MACDONNELL FREDERICK / DENNIS BRIAN / BILLO RICHARD / PRIEST JOHN
Applicant(s):     UNIV TEXAS
 
Also published as: WO2014149156 / CA2907122 / U2014238435
Methods for the conversion of lignites, subbituminous coals and other carbonaceous feedstocks into synthetic oils, including oils with properties similar to light weight sweet crude oil using a solvent derived from hydrogenating oil produced by pyrolyzing lignite are set forth herein. Such methods may be conducted, for example, under mild operating conditions with a low cost stoichiometric co-reagent and/or a disposable conversion agent.
BACKGROUND OF THE INVENTION
[0003] The present disclosure relates generally to the field of hydrocarbon synthesis. More particularly, but not exclusively, it relates to processes for the liquefaction of carbonaceous feedstocks, including lignite and coal.
[0004] Coal liquefaction is the process of producing synthetic liquid fuels from coal and other carbonaceous feedstocks. Such processes have been generally known for nearly 90 years. See, for example, Coliquefaction Studies of Waste Polymers and Lignite Influenced by Acidic and Oil-Soluble Catalysts (Gimouhopoulos et al., 2000); Influence of Heterogeneous Catalysts on the Coprocessing of Bergueda Lignite with a Vacuum Residue (Bengoa et al., 1997); Coprocessing of Bergueda Lignite with Vacuum Residue under Increasing Hydrogen Pressure. Comparison with Hydrotreating (Bengoa et al., 1995); Influence of Fe and FeMo High Loading Supported Catalysts on the Coprocessing of two Spanish Lignites with a Vacuum Residue (Font et al., 1994); Study of Iron-Based Complex Catalysts For Coal Liquefaction (Sun et al, 1989); Evaluation of the Hydroliquefaction Potential of Chinese Coals: Three Case Studies (Gao et al., 1989); Catalytic Conversions of Kansk-Achinsk Lignite to Synthetic Fuels and Chemicals (Kuznetsov et al., 1988); Hydrogenation of Lignite by Synthesis Gas (Kuznetsov et al., 1988); Function of Metal Oxide and Complex Oxide Catalysts for Hydrocracking of Coal (Tanabe et al., 1986); Catalytic Functions of Iron Catalysts for Hydrocracking of Carbon-Carbon and Carbon-Oxygen Bonds (Hattori et al., 1985); U.S. Pat. No. 5,509,945; U.S. Pat. No. 5,200,063; U.S. Pat. No. 5,071,540; U.S. Pat. No. 5,026,475; U.S. Pat. No. 4,853,111; U.S. Pat. No. 4,842,719; U.S. Pat. No. 4,839,030; U.S. Pat. No. 4,816,141; U.S. Pat. No. 4,728,418; U.S. Pat. No. 4,459,138; U.S. Pat. No. 4,385,042; U.S. Pat. No. 4,383,094; U.S. Pat. No. 4,356,079; U.S. Pat. No. 4,334,977; U.S. Pat. No. 4,332,666; U.S. Pat. No. 4,325,801; U.S. Pat. No. 4,311,578; U.S. Pat. No. 4,303,494; U.S. Pat. No. 4,300,996; US 20080011643; US 20060032788; and US 20020179493. Processes using hydrogenated coal tar distallate as the solvent have been demonstrated. See, for example, Neavel et al. (1981) and Mitchell et al. (1979).
SUMMARY OF THE INVENTION
[0005] This disclosure includes methods for the manufacture of synthetic oil (synoil), including processes for the liquefaction of lignite, coal and other carbonaceous feedstocks. In one aspect, methods for the preparation of synoil are disclosed that comprise mixing carbonaceous feedstocks with slurry oils to generate slurries; contacting the slurries with iron-containing conversion agents to generate a slurry-agent mixtures; reacting the slurry-agent mixtures at a hydrogen pressure of from 700 psi to 1,200 psi and a temperature of from 280° C. to 450° C. to generate reaction-product mixtures, whereby some or all of the carbonaceous feedstocks are converted into synoils; and separating solids from the reaction-product mixtures to form a synoil.
[0006] This disclosure includes processes for the manufacture of a solvent from a carbonaceous feedstock, which in turn may be used for the preparation of a slurry in the liquefaction process.
[0007] This disclosure includes methods for the preparation of a solvent, comprising: pyrolyzing a carbonaceous feedstock whereby some or all of the carbonaceous feedstock is converted to a pyrolysis oil; contacting the pyrolysis oil with an iron-containing conversion agent to form a pyrolysis oil-agent mixture; and reacting the pyrolysis oil-agent mixture at a hydrogen pressure from 300 psi to 1,000 psi and a temperature from 300° C. to 400° C. to generate a solvent.
[0008] This disclosure also includes carbonaceous compositions comprising a material formed from the pyrolysis of a carbonaceous feedstock, wherein the material has a boiling range between 80° C. to 600° C. as determined using the ASTM 2887 protocol.
BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The following drawings illustrate by way of example and not limitation, aspects of the present disclosure. For the sake of brevity and clarity, every feature of a given structure is not always labeled in every figure in which that structure appears. Identical reference numbers do not necessarily indicate an identical structure. Rather, the same reference number may be used to indicate a similar feature or a feature with similar functionality, as non-identical reference numbers.
[0010] FIG. 1 depicts a schematic diagram for one of the present processes;
[0011] FIG. 2 depicts a schematic diagram for one of the present processes;
[0012] FIG. 3 depicts a schematic diagram for one of the present processes;
[0013] FIG. 4 depicts a chromatogram for pyrolysis oil produced by one of the present processes;
[0014] FIG. 5 depicts a chromatogram for hydrogenated pyrolysis oil produced by one of the present processes;
[0015] FIG. 6 depicts a chromatogram for synthetic crude oil produced by one of the present processes; and
[0016] FIG. 7 depicts an exemplary <1>H NMR of a synoil produced by one of the present processes.


DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0017] The disclosure provides processes for the conversion of lignites, subbituminous coals and other carbonaceous feedstocks into synthetic oils, including oils with properties similar to light weight sweet crude oil. The disclosure further provides methods for the preparation of solvents that may be used in processes for the conversion of lignites, subbituminous coals and other carbonaceous feedstocks into synthetic oils. In certain embodiments, such processes may be carried out under mild operating conditions with a low cost stoichiometric co-reagent and/or a disposable catalyst.
Definitions
[0018] The term “carbonaceous feedstock” refers to compositions comprising lignite, subbituminous coal, low-ranked coal, and/or heavy petroleum. In certain embodiments, the carbonaceous feedstocks comprise 10% to 100% volatile carbon material, such as low rank coals. The term “volatile material” as set forth herein, refers to compounds, other than water, that are released from the feedstock when it's heated in an inert gas, like nitrogen. In certain embodiments, the volatile material comprises a mixture of short and long chain hydrocarbons and aromatic hydrocarbons.
[0019] The term “lignite” refers to a yellow to dark brown or, in some embodiments, a black coal that is an intermediate between peat and subbituminous coal according to the coal classification used in the United States and Canada. In certain embodiments, lignite comprises between 15% to 70% of moisture, an equal mix of volatile and fixed carbon, and some inorganic compounds, such as metal oxides and sulfur. Furthermore, certain forms of lignite have high levels of oxygen in its polymeric structure, up to 20% of its dry weight. As coals get higher in rank, the fixed carbon increases, volatiles decrease, and oxygen decreases.
[0020] The term “substantially” and its variations (e.g., “approximately” and “about”) are defined as being largely but not necessarily wholly what is specified (and include wholly what is specified) as understood by one of ordinary skill in the art. In any disclosed embodiment, the terms “substantially,” “approximately,” and “about” may be substituted with “within [a percentage] of what is specified, where the percentage includes 0.1, 1, 5, and 10 percent.
[0021] The terms “a” and “an” are defined as one or more unless this disclosure explicitly requires otherwise.
[0022] The terms “comprise” (and any form of comprise, such as “comprises” and “comprising”), “have” (and any form of have, such as “has” and “having”), “include” (and any form of include, such as “includes” and “including”) and “contain” (and any form of contain, such as “contains” and “containing”) are open-ended linking verbs. As a result, a method or composition that “comprises,” “has,” “includes” or “contains” one or more steps or elements possesses those one or more steps or elements, but is not limited to possessing only those one or more elements. Likewise, a step of a method or an element or component of a composition that “comprises,” “has,” “includes” or “contains” one or more features possesses those one or more features, but is not limited to possessing only those one or more features. Additionally, terms such as “first” and “second” are used only to differentiate steps, structures, features, or the like, and not to limit the different structures or features to a particular order.
[0023] Additionally, terms such as “first” and “second” are used only to differentiate structures, features, or steps, and not necessarily to limit the different structures, features, or steps to a particular order.
[0024] The above definitions supersede any conflicting definition in any of the reference that is incorporated by reference herein. The fact that certain terms are defined, however, should not be considered as indicative that any term that is undefined is indefinite.
Liquefaction Methods for Carbonaceous Feedstock
[0025] Some embodiments of the present methods for the preparation of synthetic oil (synoil) comprise mixing carbonaceous feedstock with oils to generate slurries; contacting the slurries with iron-containing conversion agents to generate a slurry-agent mixtures; reacting the slurry-agent mixtures at a hydrogen pressure of from 700 psi to 1,200 psi and a temperature of from 280° C. to 450° C. to generate reaction-product mixtures, whereby some or all of the carbonaceous feedstocks are converted into synthetic oils (synoils); and separating solids from the reaction-product mixtures. In some embodiments, the oil comprises light to intermediate crude oils and/or hydrogenated pyrolysis oils.
[0026] Some embodiments of the methods provided herein may be used, for example, for the conversion of lignites, subbituminous coals and other carbonaceous feedstocks into synoils, including oils with properties similar to medium to light weight sweet crude oil. Such methods may be conducted, for example, under mild operating conditions with stoichiometric co-reagents and/or disposable catalysts. In some embodiments, the methods disclosed herein may serve as low cost processes for producing a synthetic crude oil feedstock from, for example, lignite or subbituminous coal supplies. Synoil may serve as an acceptable substitute or alternative to petroleum based crude oils as a feedstock for oil refineries.
[0027] In some embodiments, synoil produced from the processes disclosed herein is lower in cost than such crude-oil alternatives. Moreover, in some embodiments, it is low in sulfur. In some embodiments, the method may produce less greenhouse gases than crude oil alternatives. In some embodiments, it is equivalent to, or of higher quality than petroleum crudes. Synoil produced using the methods provided herein may also serve as substitute for crude oil for the plastics industry.
[0028] In some embodiments, the processes disclosed herein may emit less greenhouse gases and/or other pollutants than conventional crude extraction and refining, the Fischer-Tropsch process, and/or direct combustion of the coal.
[0029] FIG. 1 depicts a simplified process-flow diagram illustrating general, exemplary embodiments of the apparatuses and methods of the present disclosure. This diagram is offered for illustrative purposes only, and thus it merely depicts specific embodiments and is not intended to limit the scope of the claims in any way. In the embodiment shown in FIG. 1, lignite/subbituminous coal and/or other carbonaceous feedstock is mixed in a first step (step 1 in FIG. 1) with a solvent (slurry oil) to produce a slurry. In certain embodiments, the solvent or slurry oil is light crude oil, pyrolysis oil, hydrogenated pyrolysis oil, intermediate crude oil, used motor oil, diesel, xylenes, tetralin, aliphatic hydrocarbons or aromatic hydrocarbons or mixtures thereof.
[0030] In certain embodiments, the feedstock is dried to less than 20% moisture prior to mixing with a solvent. The slurry is heated under hydrogen pressure in a suitable reactor at a temperature above 200° C. while being mixed. In some embodiments, the reactor may be a continuously stirred, or backflow mixed, batch, or continuous plug flow type. An iron containing conversion agent or catalyst may be introduced, for example, as fine particles into the slurry or as a fixed bed in the reactor. During this step, a significant portion of the coal is transformed into liquid and/or gas. The gases can be used as fuel gas to provide heat for the overall process. In other embodiments, the mixture of the carbonaceous feedstock and solvent is allowed to sit for a period of time prior to the introduction of the conversion agent.
[0031] The heated slurry is delivered to a separator in a second step, in some embodiments, where the solids are removed from the liquid carrier phase. This could be accomplished, for example, with a large scale centrifuge. Keeping the slurry temperature above 200° C. reduces the viscosity of the oil. The solid material removed in this step is expected to be mostly inorganic (minerals, metal oxides, etc.) with some small amount of fixed carbon. The liquid volume exiting this step is expected to be larger than the liquid volume entering the first step. The net difference represents the synthetic crude product or synoil, which can be processed by oil refineries.
[0032] In certain embodiments, a portion of the synoil is recycled for use in the preparation of the slurry of the carbonaceous feedstock. When the synoil is generated, a portion of it is mixed with the slurry oil or solvent that is added to the carbonaceous feedstock to form a slurry. This “recycling” of the generated synoil is illustrated in FIG. 1 where a portion of the synoil designated as “solvent” is added to the reactor containing the slurry prepared from carbonaceous feedstock.
[0033] In other embodiments, the portion of the synoil that is recycled is hydrogenated prior to recycling. This step is illustrated in FIG. 2 where a portion of the synoil designated as “solvent” is hydrogenated prior to being added to the reactor containing the slurry prepared from carbonaceous feedstock. The hydrogenation step is carried out in accordance with known methods. See for example, U.S. Pat. No. 6,139,723, U.S. Pat. No. 4,379,744, U.S. Pat. No. 4,251,346, U.S. Pat. No. 5,064,527, U.S. Pat. No. 5,783,065, all of which are incorporated herein by reference. In certain embodiments, the hydrogenation of the recycled liquid volume is carried out at a temperature of 300-400° C. In other embodiments, the hydrogenation step is carried out for a period of 10 minutes to an hour at a pressure of 100 to 1000 psi. Following the hydrogenation step, the recycled liquid synoil is added to the reactor as a solvent.
[0034] FIG. 3 depicts one embodiment of the present processes for the preparation of a solvent that is useful for mixing the carbonaceous feedstock during the preparation of the slurry discussed previously. In a first step of this process, a carbonaceous feedstock is pyrolyzed in a reactor under vacuum conditions (1 atmosphere absolute pressure or less). The pyrolysis reaction is either a fast pyrolysis reaction or a slow pyrolysis reaction. The pyrolysis reaction generates water, char (carbon rich solid fuel), gas and pyrolysis oil as product. The pyrolysis oil generated in this process has a specific gravity between 0.9 and 1.0.
[0035] In a second step of the process set forth in FIG. 3, the pyrolysis oil generated in the first step is heated under hydrogen pressure in a suitable reactor at a temperature above 200° C. for a period of up to 2 hours. In certain embodiments, the pyrolysis oil is heated in the presence of an iron-containing catalyst at a temperature of 300-400° C. An oil product that results from the second step may be used as a solvent (oil product solvent) for the carbonaceous feedstock in a process for the liquefaction of the feedstock.
[0036] In certain embodiments, the steps of the process for the preparation of synoil are repeated (FIG. 1 and FIG. 2). In some of these embodiments, some or all of the slurry oil used in a repeated mixing step comprises synoil from a previous reacting step.
[0037] In certain embodiments, prior to use, the oil product solvent is mixed and diluted with pyrolysis or hydrogenated pyrolysis oils derived from the same carbonaceous feedstock from which the oil product solvent is derived. In other embodiments, the oil product solvent is mixed and diluted with pyrolysis or hydrogenated pyrolysis oils derived from a carbonaceous feedstock that is different from the feedstock that produced the oil product solvent.
[0038] In an embodiment, a portion of the synoil obtained from the liquefaction process is removed and reused in the preparation of a slurry of the carbonaceous feedstock. When the synoil is reused, additional solvent may be optionally added to the synoil. In certain embodiments of the invention, the quantity of the synoil that is reused in the liquefaction process ranges from 15% to 85% by volume.
[0039] In certain embodiments, the synoil obtained in the liquefaction process is subjected to a separation method. In an embodiment, the synoil is subjected to fractional distillation and the components of the synoil are separated out. One or more of the separated synoil components may be mixed together to provide solvents for use in the preparation of slurries of carbonaceous feedstock.
[0040] FIGS. 4-6 depict chromatograms for pyrolysis oil, hydrogenated pyrolysis oil, and synthetic crude oil respectively, produced by some embodiments of the processes disclosed herein. The pyrolysis oils contain a significant amount of oxygenated species that are removed in the hydrogenation process. All three oils have a strong aliphatic hydrocarbon distribution, although the synthetic crude has the highest concentration. The distribution of boiling fractions is comparable to petroleum crude oil. Further details are provided in the Working Examples below.
Carbonaceous Feedstocks

[0041] A wide variety of carbonaceous materials may be used as feedstocks for the methods disclosed herein, including, but not limited to, lignite, sub-bituminous coal, low-ranked coal, and heavy petroleum. In the case of lignites, the ash content may vary. For example, in some embodiments, it may be less than 37%, preferably, less than 15% on a dry basis. In some embodiments, it is advantageous to remove moisture from the carbonaceous feedstock prior to the mixing step. In some embodiments, the ratio of carbonaceous feedstock to the slurry oils (discussed in greater detail below) is about 1:1 to 1:3 by weight. In some of these embodiments, the iron-containing conversion agent (also discussed in greater detail below) is mixed with a loading factor of from 10% to 30% by weight with the carbonaceous feedstock.
[0042] In some embodiments, in the case of lignites, source and composition have an effect on product yield, as discussed further in Example 7. In some embodiments, the lignite would be fresh and have high volatile carbon content and low ash content. In some embodiments, such lignite may need to be cleaned to remove clay and ash, which may be done by methods such as froth flotations, float/sink separation, reverse froth flotation, centrifugation, acid or caustic washes, with or without surfactants, and dry fluidized bed separation.
[0043] In certain embodiments, the carbonaceous feedstock material used in the processes is crushed to a particle size of 10-mesh or less, which are particles that can pass through a 10-mesh sieve.
Hydrogenated Pyrolysis Oil and Other Slurry Oils
[0044] The carbonaceous feedstock may be mixed with a variety of solvents or slurry oils, including for example, light crude oil, pyrolysis oil, hydrogenated pyrolysis oil, intermediate crude oil, used motor oil, diesel, xylenes, tetralin, aliphatic hydrocarbons or aromatic hydrocarbons or mixtures thereof. In some of the embodiments disclosed herein, hydrogenated pyrolysis oil is an oil that is derived from the pyrolysis of a carbonaceous feedstock followed by a hydrogenation step. Pyrolysis is a thermochemical decomposition of organic material at elevated temperatures in the absence of oxygen, typically occurring under low pressure and at operating temperatures above 430° C. (800° F.). The oil derived from a carbonaceous feedstock that is subjected to pyrolysis is referred to as “pyrolysis oil.”
[0045] In certain embodiments, the pyrolysis oil is derived from lignite. In other embodiments, the pyrolysis oil derived from lignite is subjected to a hydrogenation step to form a hydrogenated lignite pyrolysis oil.
[0046] The initial pyrolysis oil, e.g., the pyrolysis oil used for the first one or more process cycles, may be made by rapidly heating lignite or other carbonaceous material in the absence of oxygen. In this embodiment, 80 mL of oil can be produced from 1.0 kg of lignite. Such an oil may be further hydrogenated using conventional techniques to produce an effective lignite/subbituminous solvent, which is also referred to as hydrogenated pyrolysis oil herein. In some embodiments, hydrogenated pyrolysis oils are obtained from processes comprising heating the carbonaceous feedstock in the absence of oxygen to produce a pyrolyzed lignite oil, and hydrogenating some or all of the pyrolyzed lignite oil with hydrogen in the presence a conversion agent to produce the hydrogenated pyrolysis oil. Suitable reducing conditions include heating at temperatures from 250° C. to 350° C., H2 pressures from 400 psi to 700 psi and reaction times from 30 to 360 minutes. Catalysts that may be used for the hydrogenation/reduction include, for example, the iron-containing conversion agents described below. In some embodiments, the catalyst comprises 5-40% by mass metallic iron on alumina support.
[0047] Suitable hydrogenated pyrolysis oils that may be used with the methods disclosed may be characterized by some or all of the following properties, including a boiling range between 80 to 600° C. as determined using the ASTM 2887 protocol, which is incorporated herein by reference, and/or an elemental composition comprising 80 to 85% carbon by mass and 8 to 12% hydrogen by mass.
[0048] In subsequent cycles of the method, the hydrogenated pyrolysis oils may comprise synoil resulting from the methods provided herein. For example, some or all of the slurry oil used in a repeated mixing step may comprise synoil from a previous reacting step.
Iron-Containing Conversion Agent
[0049] A broad range of iron containing conversion agents are compatible with the liquefaction methods disclosed herein, including, for example, substances derived from bauxite, red mud, iron oxide(s), and/or various iron-containing salts deposited on alumina. Suitable iron containing conversion agents will have iron contents from 5% to 40% by weight in some embodiments and/or have an average particle size of 60 to 300 mesh.
[0050] In the case of bauxite, the substance may be prepared by a process comprising crushing bauxite ore. Bauxite is a general term for a rock composed of hydrated aluminum oxides and is usually found containing up to 30% iron oxides. Typically, bauxite is mostly comprised of the minerals gibbsite Al(OH)3, boehmite γ-AlO(OH), and diaspore α-AlO(OH), in a mixture with two iron oxides, goethite and hematite, the clay mineral kaolinite, and small amounts of anatase TiO2. Typical mesh sizes for the crushed bauxite particles will range from 60 to 300 mesh. Once they are crushed, the bauxite particles may be calcined in some embodiments, for example, at 300 to 600° C. in the presence of oxygen to produce calcined bauxite particles. Reduction of crushed bauxite or calcined bauxite particles with H2 produces iron-containing conversion agents. In some embodiments, the reducing further comprises heating the bauxite particles to about 250° C. to 400° C. and an H2 pressure is from 0.5 psi to 1,000 psi. Under such conditions, calcined bauxite particles will typically be reduced in about 30 to 180 minutes.
[0051] Iron-containing conversion agents may also be prepared by wetting Al2O3 particles with aqueous solutions of iron salts to generate iron-alumina compositions. Examples of suitable iron salts include: iron(III) nitrate, iron (III) chloride, iron (III) citrate, iron (II) chloride, iron (II) sulfate, iron (II) ammonium sulfate, and combinations and/or hydrates thereof. Calcining the iron-alumina composition at, for example, at from 300° C. to 600° C. in the presence of oxygen may then be used to produce a calcined iron-alumina composition, which can then be reduced with H2 to produce the desired iron-containing conversion agents. Suitable reducing conditions include temperatures from 250° C. to 400° C., H2 pressure from 0.5 psi to 1000 psi and reaction times from 30 to 180 minutes.
[0052] Substances derived from red mud may also serve as suitable iron containing conversion agents. Red mud is composed of a mixture of solid and metallic oxide-bearing impurities, and is typically a disposal problem for the aluminum industry. The red color is attributed to oxidized iron (rust), which can account for up to 60% of the mass of the red mud. In addition to iron oxide, e.g., Fe2O3, red mud typically comprises silica (SiO2), residual aluminum, alumina (Al2O3) and titanium oxide. In some embodiments, the iron oxide content of the red mud is 30% to 60% by mass. In some embodiments, the Al2O3 content of the red mud is 10% to 20% by mass. In some embodiments, the SiO2 content of the red mud is 3% to 50% by mass.
[0053] Further preparation steps include, for example, calcining the red mud particles at 300 to 600° C. in the presence of oxygen to produce calcined red mud particles, and then reducing the calcined red mud particles with H2 to produce the iron-containing conversion agent. Suitable reducing conditions include temperatures from 250° C. to 400° C., H2 pressure from 0.5 psi to 1,000 psi and reaction times from 30 to 180 minutes.
[0054] Other suitable types of iron-containing conversion agents may also be derived from the solids separated from the reaction-product mixture. In some embodiments, the iron-containing conversion agents comprise metallic iron finely dispersed on a substrate of aluminum oxide having an average particle size of 60-300 mesh.
[0055] In some embodiments, the iron-containing conversion agent is made by crushing bauxite ore having an iron content between 5 and 40% by mass, to particles with a mesh size of 60-300 mesh. These crushed particles are then washed with water, dried in air, calcined at 300° C. for approximately 30 min Afterwards the iron content in the particles is reduced to metallic iron at 300° C. by addition of H2 gas (0.5 psi to 1000 psi).
[0056] In some embodiments, the iron-containing conversion agent is disposable. In other embodiments, it may be isolated from the solid by-products and regenerated by back addition of iron salts, calcining, and hydrotreatment. In this aspect, it may be used in a catalytic fashion. In still further embodiments, the solid by products may be isolated and sold as a bauxite-type ore.
[0057] Iron-containing conversion agent comprising both aluminum oxide and metallic iron may be used in some embodiments to improve liquefaction yields. For example, a liquefaction run using 3 g iron-containing conversion agent and 25 g lignite coal gave synoil yields of up to 50% of the theoretical value that may be expected from the carbon content of the lignite feedstock (MAF yield). This is compared to a yield of up to 20% MAF yield when the same process is repeated in the absence of this iron-containing agent.
Hydroconversion Reactions
[0058] In some embodiments, the methods disclosed herein combine the hydrogenation and liquefaction of the carbonaceous material in a single step. By combining these two steps, it is possible to avoid the need for a separate hydrogenation step to recharge the solvent, which in turn reduces equipment and operating costs. Also, the H2 pressures utilized in some of the embodiments are significantly less than the pressures used in current commercial coal-to-liquids processes.
[0059] An example of a suitable process for the liquefaction of a carbonaceous feedstock can be summarized as comprising the following: (a) mixing and dispersion of the feedstock in a slurry oil in a 1:2 mass ratio, (b) addition of an iron-containing conversion agent with a loading factor of 10-30% by mass with respect to the feedstock mass, (c) placing the resulting slurry under a hydrogen atmosphere in a pressure vessel and rapidly heating to 280-450° C. and adjusting the partial pressure of hydrogen to 700 to 1,200 psi hydrogen at maximum temperature, (d) agitating mechanically with a residence time of 10-30 min at maximum temperature, and (e) separating the solids and water from the resulting liquid, which will be present in greater amounts than that of the initial slurry oil by 110% to 140% by weight. The liquid (synoil) will be comparable to a medium sweet crude oil.
[0060] Suitable reactors for the hydroconversion reactions include continuous flow or batch hydrogenation reactor technology. Scaling up the processes disclosed herein should enable the production of, for example, 1,000 to 20,000 barrels of synoil per day. In some embodiments, the hydroconversion reactions may be used to convert 35 to 75% of the carbon content in the original solid feedstock to a liquid product. For coal this corresponds to synoil yields of 40% to 80% by mass based on moisture, ash-free (MAF) coal. This MAF yield is comparable to current processes, as shown in Table 1, and it may be more economical.
TABLE 1
MAF Yield of Current Coal Extraction Processes
  Process  MAF % yield  Typical feedstock
  Invention  51  Lignite
  Solvent Refined Coal  54  Subituminous
  (SRCI&II) (USA)*   
  H-coal Process (USA)*  65  Bituminous
  Exxon EDS (USA)*  35  Bituminous
  Kohloel (Germany)*  75  Bituminous
  BCL-NEDOL (Japan)*  52  Subituminous
  Shenhua (China)*  57  Subituminous
Kabe, T., Ed., 2004. Studies in Surface Science and Catalysis: Coal and Coal-Related Compounds, Elsevier, Amsterdam.
[0061] In some embodiments, only mild pressure and temperature are needed (around 320° C. and 1000 psi of H2). In some embodiments, a digestion time of 20 to 30 minutes is optimal. In some embodiments, lignite quality is important (specifically lignite should be fresh and have a low ash and high volatility content). In some embodiments, the removal of moisture from the lignite is optional. In some embodiments, a catalyst is preferred; for example, Fe/alumina may be used.
Synthetic Oil (Synoil)
[0062] Oils produced though pyrolysis of lignite, without isolating specific boiling fractions, are effective solvents for the liquefaction of lignite/subbituminous coal. In addition, the liquids obtained through pyrolysis can be hydrogenated with mild process conditions (<1,000 psi) compared to processes used to hydrogenate coal tar distillates derived from bituminous and subbituminous coals, which typically require H2 pressures >2,500 psi.
[0063] The methods disclosed herein provide a process that may be used to produce higher proportions of mid-weight hydrocarbons (boiling range 200° C. to 500° C.) and lower proportions of the less desirable light (gases, naphthas) and high molecular weight hydrocarbons (waxes, asphaltenes) than the other reported processes. In an embodiment, a profile for a synoil generated by the process comprises approximately 2% naphtha, approximately 20% kerosene, approximately 30% diesel and approximately 40% lubrication oils and asphaltenes.
[0064] Compared to crude petroleum, the synoil may have lower amounts of trace elements that can make refining more difficult, as detailed further in Example 8. The concentrations of these trace elements and carbon, nitrogen, and hydrogen can be traced from the lignite and the hydrogenated pyrolysis oil to the synoil and the inertinite (solid waste). The composition of synoil produced by an embodiment of the processes enclosed herein resembles that of common fuels, such as diesel and Jet-A. Synoil having such properties are typically more desirable to a refinery, since the refinery can in turn produce more high value diesel and jet fuel products from the same amount of starting material.
[0065] FIG. 7 depicts an exemplary <1>H NMR of a synoil produced by one embodiment.
[0066] Table 2 shows estimated refinery products of the synoil made by an embodiment of the methods disclosed herein. This is comparable to the yield of crude petroleum alternatives.
TABLE 2
Simulated Refinery Yields for Synoil
Maximum Jet Production
  CTL SynOil    CTL SynOil 
  Raw Yield    Hydrocracked Yield 
  Product  Max Jet    Max Jet 
  Cut  (BPD)  Vol %  (BPD)  Vol %
  Gas  0  0.0%  34  3.1%
  Gasoline  7  0.7%  174  16.0%
  Jet  209  20.9%  526  48.3%
  Diesel  269  26.9%  269  24.7%
  Gas Oil  429  42.9%  0  0.0%
  Resid/HFO  86  8.6%  86  7.9%
  Total  1000  100.0%  1089  100.0%
[0067] The environmental cost of making Jet-A (JP-8) fuel using an embodiment of the process disclosed herein can be calculated, in some embodiments, by comparing air pollutants produced, water pollutants produced, and environmentally beneficial waste products produced compared to alternatives.
[0068] The synoil yields of the current process range from 40 to 80% by mass of the available carbon and hydrocarbons in the lignite or subbituminous coal feedstock being converted into synoil (MAF yield) which is comparable with most of the existing CTL processes reported in the literature; however, the process conditions disclosed herein are significantly milder and therefore more economical. Typical temperature and pressure process conditions for the processes disclosed herein range from 280-450° C. and 700-1200 psi, whereas typical pressures for other reported processes are in excess of 2000 psi and temperatures are usually between 380-500° C.
[0069] In some embodiments, it may be desirable or even necessary to removing water from the reaction-product mixture in order to generate a substantially water-free synoil.
[0070] Synoil may be characterized in some embodiments by one or more of the following parameters: a specific gravity of 0.84 to 1.00 g/mL and an API gravity between 37 and 10, a sulfur content of less than 1.0% sulfur by mass, and kinematic viscosity of less than 15.0 cSt at 38° C.
[0071] Moreover, in some embodiments, the synoil may be characterized by its boiling range. For example, the methods provided herein may be used to produce synoil wherein 90% of the synoil boils below 538° C. as determined using the ASTM 5307 protocol, which is incorporated herein by reference.
[0072] Synoil may also be characterized by its elemental composition. For example, the methods of the present disclosure may be used to synthesize synoil having an elemental composition comprising 82% to 86% carbon by mass and 10% to 14% hydrogen by mass.
[0073] Solubility in other solvents may also be used to characterize synoil. In some embodiments, the synoil is readily soluble in toluene and heptane.
[0074] Table 3 sets forth a summary analysis of the properties and characteristics of the synoil generated from lignites.
TABLE 3
Summary Analysis of Synoil from Lignites
  Acid number (TAN)  3.46  KOH/g
  Elemental   
  Carbon  81.7  WT %
  Hydrogen  9.88  WT %
  Nitrogen  0.44  WT %
  Oxygen  5.78  WT %
  Sulfur  0.645  WT %
  Metals   
  Nickel  <49  ppm
  Vanadium  25.4  ppm
  Mercury  <2  ppm
  SARA   
  Asphaltenes  18  WT %
  Saturates  17.5  WT %
  Aromatics  61.2  WT %
  Resins  3.3  WT %
  Simulated   
  Distillation   
  IBP  251  ° F.
   5% off  399  ° F.
  10% off  440  ° F.
  15% off  475  ° F.
  20% off  503  ° F.
  25% off  529  ° F.
  30% off  558  ° F.
  35% off  584  ° F.
  40% off  620  ° F.
  45% off  655  ° F.
  50% off  693  ° F.
  55% off  731  ° F.
  60% off  766  ° F.
  65% off  799  ° F.
  70% off  830  ° F.
  75% off  864  ° F.
  80% off  914  ° F.
  85% off  987  ° F.
  90% off  1070  ° F.
  95% off  —  ° F.
  % Recovered  85.8  @1000° F.
  % Residue  14.2  @1000° F.
Oil Product Solvent
[0075] In certain embodiments, a solvent is derived from the pyrolysis of a carbonaceous feedstock coupled with the treatment of the resulting pyrolysis oil with an iron-containing conversion agent. This solvent may be used to prepare a slurry of a carbonaceous feedstock. A further embodiment is directed to a carbonaceous composition comprising a material formed from the pyrolysis of a carbonaceous feedstock.
[0076] In a first step of the process for preparing an oil product solvent, a carbonaceous feedstock is pyrolyzed in a reactor under low pressure conditions (1 atmosphere absolute pressure or less). The pyrolysis reaction is either a fast pyrolysis reaction or a slow pyrolysis reaction. The pyrolysis reaction generates water, char (carbon rich solid fuel), gas and pyrolysis oil as product. The pyrolysis oil generated in this process has a specific gravity between 0.9 and 1.0.
[0077] In a second step of the process, the pyrolysis oil generated in the first step is heated under hydrogen pressure in a suitable reactor at a temperature above 200° C. for a period of up to 2 hours. In certain embodiments, the pyrolysis is heated in the presence of an iron-containing catalyst at a temperature of 300-400° C. An oil product that results from the second step may be used as a solvent for the carbonaceous feedstock in a process for the liquefaction of the feedstock.
[0078] In certain embodiments, prior to use, the oil product solvent is mixed and diluted with pyrolysis or hydrogenated pyrolysis oils derived from the same carbonaceous feedstock from which the oil product solvent is derived. In other embodiments, the oil product solvent is mixed and diluted with pyrolysis or hydrogenated pyrolysis oils derived from a carbonaceous feedstock that is different from the feedstock that produced the oil product solvent.
[0079] In an embodiment, the oil product solvent derived from a particular feedstock has a chemical profile that is similar to the synoil derived from the same feedstock.
[0080] An embodiment is directed to a solvent comprising between 40-60% of aromatic compounds. In certain embodiments, the solvent comprises between 40-60% of saturated compounds.
[0081] Suitable solvents that may be used with the methods disclosed may be characterized by some or all of the following properties, including a boiling range between 80 to 600° C. as determined using the ASTM 2887 protocol, which is incorporated herein by reference and/or an elemental composition comprising 80 to 85% carbon by mass and 8 to 12% hydrogen by mass.
[0082] Any embodiment of any of the present systems and/or methods can consist of or consist essentially of—rather than comprise/include/contain/have—any of the described steps, elements, and/or features. Thus, in any of the claims, the term “consisting of’ or “consisting essentially of’ can be substituted for any of the open-ended linking verbs recited above, in order to change the scope of a given claim from what it would otherwise be using the open-ended linking verb.
[0083] Other objects, features and advantages of the present disclosure will become apparent from the following working examples. It should be understood, however, that the detailed description and the specific examples, while indicating specific embodiments, are given by way of illustration only, since various changes and modifications within the spirit and scope of the present processes and compositions will become apparent to those skilled in the art from this detailed description.
WORKING EXAMPLES
[0084] The following examples are included to demonstrate preferred embodiments. It should be appreciated by those of skill in the art that the techniques disclosed in the examples that follow represent suitable techniques for practicing embodiments of the present processes. However, those of skill in the art should, in light of the present disclosure, appreciate that many changes can be made in the specific embodiments which are disclosed and still obtain a like or similar result.
Example 1
Hydroconversion of Lignite
[0085] Lignite (23% moisture; 9% ash; 28% volatiles; 40% fixed carbon) from Jewett, Tex. (25 g) was placed in a 450 mL Parr reactor with 50 mL hydrogenated pyrolysis oil. Moisture was removed from the mixture by heating above 100° C. under flowing hydrogen. The vessel was sealed and the reactants were heated and stirred. The mixture was heated to 375° C. for 30 min. and then cooled. The slurry was diluted with THF and filtered to remove the solids. Approximately, 1.8 g synoil (11% MAF yield) was obtained.
Example 2
Hydroconversion of Texas Lignite at 1,000 psi H2
[0086] About 25 g of lignite (23% moisture; 9% ash; 28% volatiles; 40% fixed carbon) placed in 49 g of hydrogenated pyrolysis oil with 3 g of 25% iron on alumina co-reagent called BXF1. The mixture was placed in a 450 mL Parr pressure reactor and charged with 400 psi of hydrogen gas at room temperature. The reactor was sealed and heated to 350° C. while stirring for 3 hours. The pressure reached 1000 psi. Here the moisture was not removed from the lignite before placing it in the reactor. The slurry was then cooled and filtered. About 55 g of oil was collected with 3 g of solid residue remaining (excluding co-reagent weight). This represents a 35% synoil yield based on moisture, ash-free (MAF) coal.
[0087] The experiment was repeated. In this case, 50 g of hydrogenated pyrolysis oil was used, other amounts were the same as previous run. The mixture was brought to 320° C. for 2 hours while stirring. About 56.5 g of oil was recovered (38% MAF yield).
Example 3
Hydroconversion of Lignite from Luminant
[0088] Lignite from Luminant (30% moisture, 8% ash, 29% volatiles, 33% fixed carbon) was crushed and sieved to 16 mesh. Twenty-five grams of this lignite was added to 40 g of hydrogenated pyrolysis oil and 3 g of 25% iron on alumina co-reagent. The vessel was sealed and charged with 300 psi H2 at room temperature, the mixture was brought to and held at 320° C. for 30 min while stirring. During this time the pressure reached a maximum value of 900 psi. After cooling and work-up, 47 g of oil was recovered (48% MAF yield). The carbon, hydrogen and nitrogen content of the hydrogenated pyrolysis oil was 85.2%, 10.2%, and 4.7% by mass, respectively. The carbon, hydrogen and nitrogen content of the oil recovered at the end of the experiment was 85.7%, 9.0%, and 6.5% by mass, respectively.
[0089] Lignite from Luminant (30% moisture, 8% ash, 29% volatiles, 33% fixed carbon) was crushed and sieved to 16 mesh. Twenty-five grams of this lignite was added to 50 g of hydrogenated pyrolysis oil and 3 g of 25% iron on silica co-reagent. The mixture was brought to and held at 320° C. for 30 min while stirring. After cooling and work-up, 53 g of oil was recovered (20% MAF yield). The carbon, hydrogen and nitrogen content of the hydrogenated pyrolysis oil was 85.2%, 10.2%, and 4.7% by mass, respectively. The carbon, hydrogen and nitrogen content of the oil recovered at the end of the experiment was 68.3%, 8.1%, and 3.0% by mass, respectively.
Example 4
Hydroconversion with Bauxite from Arkansas

[0090] Bauxite from Arkansas was crushed into fine powder ( ̃200 mesh) and reduced at 300° C. under 17 psi H2. The resulting solid was called BXF9. About 25 g of lignite coal from Luminant (30% moisture, 8% ash, 29% volatiles, 33% fixed carbon; 16 mesh) was mixed with the BXF9 co-reagent (3 g) and 50 g of hydrogenated pyrolysis oil in a 450 mL Parr vessel. The reactor was sealed, charged with 300 psig of H2 and heated to 320° C. The temperature was held for 30 minutes while stirring at 150 rpm, during which time the pressure reached 1000 psi. After cooling and work-up, 59 g of oil remained (59% MAF yield). The carbon, hydrogen and nitrogen content of the hydrogenated pyrolysis oil was 85.2%, 10.2%, and 4.7% by mass, respectively. The carbon, hydrogen and nitrogen content of the oil recovered at the end of the experiment was 84.3%, 9.0%, and 5.9% by mass, respectively.
[0091] Lignite from Luminant was crushed and sieved to 16 mesh and dried in a vacuum oven at 60° C. to 2% moisture or less. Eighteen grams of this lignite was added to 50 g of hydrogenated pyrolysis oil and 3 g of 25% iron on alumina co-reagent. The reactor was sealed, charged with 300 psi of H2 and heated to 320° C. The mixture was held at 320° C. for 30 min while stirring during which the pressure rose to a maximum of 900 psi. After cooling and workup, 58 g of oil was recovered (52% MAF yield).
Example 5
Scale Up
[0092] A larger scale reaction of 400 g lignite (20% moisture, 1% ash, 40+ mesh from NRG) was slurried with 812 g hydrogenated pyrolysis oil and 48 g of 25% iron on alumina co-reagent in a 2 gallon pressure reactor. The head space was charged with 234 psi H2 gas. The mixture was heated at 15° C./min to a final temperature of 320° C. at which it was held for 30 min while stirring continuously at 150 rpm. Once the temperature reached 320° C., additional H2 was introduced to make the reactor pressure 1000 psi. After cooling and work-up, 923 g of oil was recovered (49% MAF yield). The carbon, hydrogen and nitrogen content of the hydrogenated pyrolysis oil was 85.6%, 9.8%, and 3.9% by mass, respectively. The carbon, hydrogen and nitrogen content of the oil recovered at the end of the experiment was 82.5%, 9.0%, and 4.7% by mass, respectively.
[0093] A second larger reaction was performed with identical amounts with a higher yield of 51.8%) (933 g of oil recovered). The carbon, hydrogen and nitrogen content of the hydrogenated pyrolysis oil was 83.83%, 9.72%, and 2.72% by mass, respectively. The carbon, hydrogen and nitrogen content of the oil recovered at the end of the experiment was 81.22%, 9.28%, and 2.43% by mass, respectively.
[0094] A reaction identical to the first large reaction was carried out at the smaller scale (25 g lignite, 50 g hydrogenated pyrolysis oil, and 3 g co-reagent Fe on alumina) using the same reagents. This small scale reaction gave 53 g oil recovered or a 20% MAF yield. This result suggests that there may be increases in yield upon scale-up.
Example 6
Slurry Oil Hydrogenation
[0095] Factors such as time, pressure, and catalyst composition were examined to determine slurry oil varieties made by hydrogenation of synoil or pyrolysis oil. Pyrolysis oil or synoil of the composition shown in Table 4 was reacted with the given catalyst and support at the given temperature and pressure for the given time. The resulting slurry oil with catalyst, recovered at the yield and composition shown, could be mixed with a carbonaceous feedstock and then reacted to form synoil. In some embodiments, alumina was found to be a more effective support than carbon, but certain other variables resulted in similar yields, allowing for optimization based on costs.
TABLE 4
Hydrogenation of Pyrolysis Oil or Synoil into Slurry Oil

Starting Solvent:  T  P    Time    C % H %
Run  C %, H %  (C)  (psi)  Catalyst/support  (h)  Yield  After
1  Pyrolysis oil  300  400  10% Pd/C  12  44  83.2; 9.0
  64.6; 9.5
2  Pyrolysis oil  300  1000  10% Pd/alumina  8  63  83.0; 8.9
  74.8; 9.1
3  Synoil  300  400  10% Pd/alumina  8  Not  83.6; 9.6
  80.7; 8.3          determined
4  Pyrolysis oil  300  500  10% Pd/alumina  8  70   84.4; 10.4
  72.0; 10.0
5  Pyrolysis oil  300  700  25% Ni/alumina  8  71  84.9; 9.9
  72.5; 9.3
6  Pyrolysis oil  300  400  10% Pd/alumina  8  80   83.5; 10.2
  73.2; 9.6
7  Pyrolysis oil  300  700  25% Fe/alumina  8  80   84.0; 10.1
  77.9; 10.8
Example 7
Lignite Digestion
[0096] Once a hydrogenated pyrolysis oil or synoil is made, lignite is slurried in this oil under a hydrogen atmosphere at various temperatures and pressures in the presence or absence of a catalyst, yielding synoil after work-up. Many variables were considered including lignite source, composition, and inherent moisture; type of catalyst; type of catalyst support; temperature; pressure; hydrogen partial pressure; steam partial pressure; rate of heating and cooling; stirring rate; lignite particle size, solvent to lignite ratio; and catalyst to lignite ratio. Select results are shown in Table 5.
TABLE 5
Lignite Digestion Varieties
      Oil  Max  Oil  Slurry oil  Synoil 
  Lignite  Solvent  Recv'd  Yield  Yield  C % H %  CH %
Run  (g)  (g)  (g)  (g)  g (%)  Before  After  Notes
 3<#>  25.0 LAL  ~40  42  17.0    2 g  83.0; 8.9;   80.7; 8.3  Moisture removed in
          (12%)      solvent, no added
                conversion agents.
                Heat to 320° C. for
                30 min
 8<#>  25.0 LAL  49.0  55.0  17.0  6.0 g  83.2; 10.8  81.0; 9.9  3.0 g BXF1 w/H2O
          (35%)      w/300 psi H2 at 25°
                C. Heat to 320° C.
                for 30 min
#21  25 LAL  50  51.5  17    1.5  86.5; 10.2  85.1; 9.9  3.0 g ironsulfide
           (8%)      (FeS) 100 mesh 300
                psi H2, at 25° C.
                Pressure reached at
                1350 psi at 340° C.
                Heated for 30 min
#22  25 LAL  50  42.9  17  −8   86.5; 10.2   84.4; 10.2  No added conversion
                agent. Max pressure
                was 1000 psi with H2
                at 320° C. for 30 min.
#23  25 NRG  50  57.5  16.2    7.5  86.5; 10.2  85.1; 9.8  3.0 g BXF1, 320° C.
          (46%)      for 30 min.
                Max pressure was
                800 psi H2
#24  25 LAL  50  54.2  17    4.2  84.6; 9.8   84.2; 9.9  3.0 g metallic Fe(l-3
          (25%)      micron), 320° C. for
                30 min.
                800 psi H2 at 320° C.
                Heat for 30 min.
#25  25 LAL  50  54.5  17    4.5  84.6; 9.8    85.3; 10.8  3.0 g metallic Fe (325
          (26%)      mesh), 700 psi Hz
                at 320° C. for 30 min
#36  25 NRG  50  60  16.2  10   84.8, 8.7    85.2, 10.8  3.0 g BXF1, 300 psi
          (61.7%)        w/H2 at 25° C. Heat to
                320° C., regular rpm
                (150), fast heating
                (30-40 min)
#37  25 NRG  50  57  16.2  7  84.8, 8.7    85.1, 10.2  3.0 g BXF1, 300 psi
          (43.2%)        w/H2 at 25° C. Heat
                to 320° C. for 30 min.,
                regular rpm (150),
                BXF1 added after
                removing H20
#45  NRG 16  50  56.8  16.2    6.8   85.2, 10.25  81.17, 9.01  3.0 g BXF1, 300 psi mesh (42%) w/H2 at 25° C. Heat 320° C. for 30 min., regular rpm, regular heating and cooling
#49  Luminant  50  59  15.4  9   85.2, 10.25   84.3, 8.95  3.0 g BXF9, 300 psi 216 mesh (58%) w/H2 at 25° C. Heat at 320° C. for 30 min regular rpm, fast heating and cooling
#50  NRG 16  50  53  16.2  3   85.2, 10.25   83.9; 10.5  2 g BXF1, 300 psi mesh (18%) w/H2, Heated to 320°C. for 30 min, regular rpm, fast heating and  slow cooling
#51  LAL  50  50  17  0  84.6; 10.5  < >84.1; 10.2;  3 g BXF1,
(0%)      pressurized to 300 psi w/syngas (1 CO: 2 H2) and heated to 320° C. for 30 min.
 Max pressure was 1000 psi.
#52  Luminant  50  53  15.4  3   85.2, 10.25  68.28, 8.10  3.0 g 25% metallic Fe
2 (20%) on deposited on SiO2, 16 mesh 300 psi w/H2 at 25° C., then heated to320° C. for 30 min,  regular rpm, fast heating and cooling
[0097] A typical run consisted of loading 25 g of lignite (with known ash and moisture content, shown in Table 4) into a 450 mL Parr pressure reactor with 50 g of slurry oil and various amounts of BXF1 or other conversion agent. The reactor was sealed and charged with different partial pressures of hydrogen. The reactor was then heated to the desired temperature for 30 min with stirring at 100 rpm. After cooling and work-up, the product is analyzed. Best yields were typically found with mild temperature and pressure, 20-30 minute digestion time, and Fe/alumina conversion agent.
[0098] Yields also depended on the type of coal, as shown in Table 5. Removal of moisture in the lignite was optional, but the freshness, ash content (lower the better) and volatility (higher the better) were significant. The results in Table 6 can thus be explained by the compositional analysis in Table 7.
TABLE 6
Synoil Yields and Lignite Source
Coal  Oil Yield %
Luminant 2 (TX)  51%
NRG (TX)  49%
Jewett (TX) LAL  38%
Benton (AR)  33%
Malvern (AR)  9%
TABLE 7
Proximate Analysis of Lignite Coals
% fixed  
Lignite Source  % moisture  % volatiles  carbon  % ash
Jewett  31  31  23  15
LAL (from Jewett)  23  28  40  9
Benton  34  39  20  7
Malvern (old)  32  25  18  26
NRG  24  31  34  11
Luminant 1 (LI)  29  21.8  31.5  17.7
Luminant 2 (L2)  30  29  32.5  8.5
Example 8
Characterization of Synoil
[0099] Lignite is slurried with hydrogenated pyrolysis oil under a hydrogen atmosphere in the presence of a conversion agent under varied temperature and pressure, resulting in synoil. This synoil is then tested and determined to have an elemental composition of between 80 and 85% carbon, 7 to 10% hydrogen, and 0.5 to 5% nitrogen by mass. This is close to the ideal oil values of 86% carbon and 14% hydrogen. Sulfur content was typically 0.5% or less which classifies this as a low sulfur or “sweet” crude substitute. By difference, the oxygen content ranged from 2-8%, most typically around 5%.
[0100] Trace metal content is important as high levels of certain metals are known to make refining the synoil into finished products more difficult, and thus can cause the synoil product to lose some value. Table 8 shows trace metal as well as sulfur contents in the synoil produced compared to crude oil alternatives. The synoil made by this embodiment is of low viscosity (13 cSt @ 38 C), is soluble in tetrahydrofuran, and has a specific gravity of 0.82-1.0. By boiling fractions and viscosity it can classified as a medium sweet crude oil.
TABLE 8
Trace Metal & Sulfur Concentrations in Intermediate Oils, Synoils & Crude Oils
Fe  
Sample  Hg (ppm)  Ni (ppm)  V (ppm)  (ppm)  S (%)
Pyrolysis oil  <2  0.21  <1  —  1.28
Hydrogenated  <2  1.5  <1  103  0.39
pyrolysis oil          
Synoil 1  <2  1.25  <0.9  125  0.30
Synoil 2  1.41  0.57  7.52  —  —
Synoil 3  0.68  0.81  37.1  —  —
Boscan crude oil<1>  —  90  920  —  —
Maya crude oil<1>  —  39  242  —  —
Cerro Negro crude<1>  —  120  307  —  —
<1>Petroleum Chemistry and Refining by James G. Speight, J. G. Speight (1997)
Example 9
Catalytic Lignite Digestion

[0101] Low-ash lignite (25 g) was slurried with 50 mL hydrogenated pyrolysis oil with no conversion agent. The reaction was kept at 100° C. for 1 hour and 45 minutes with minimum H2 flow monitored through bubbler. The reactor was sealed and heated to 375° C. for 30 minutes, with maximum temperature 388° C. and maximum pressure 350 psi. This uncatalyzed reaction yielded 2-3 g of oil.
[0102] Another 25 g of low-ash lignite was slurried with 50 mL hydrogenated pyrolysis oil with the addition of 3 g of 25% Fe on alumina. The reactor was charged with 300 psi of H2 and fast heated to 320° C., allowing it to react at 1000 psi for 3 hours. This catalyzed reaction yielded 8-9 g of oil, proving the importance of the reaction conditions.
Example 10
Refining Synoil

[0103] Synoil (80 g, 85% carbon and 10% hydrogen) made by one of the methods disclosed herein was separated by fractional distillation. Table 9 provides the mass of each fraction and its correspondence.
TABLE 9
Fractional Distillation of Synoil

Boiling Range (C.)  Mass (g) and yield (%)  Notes
25-190  1.5 g (1.9%)  Naphtha
190-250  18.5 g (23%)    Kerosene (JP-8)
250-350  25 g (31%)  Diesel
350+ (bottoms)  35 g (44%)  Lubrication oils and asphaltenes
[0104] Simulated distillation was performed on synoil from Luminant coal. The yield of each type of fuel from a refinery can be estimated in Table 10.
TABLE 10
Estimated Refinery Yields
Maximum Jet Production
CTL SynOil    CTL SynOil  
Raw Yield    Hydrocracked Yield 
Product  Max Jet    Max Jet  
Cut  (BPD),  Vol %  (BPD)  Vol %
Gas  0  0.0%  34  3.1%
Gasoline  7  0.7%  174  16.0%
Jet  209  20.9%  526  48.3%
Diesel  269  26.9%  269  24.7%
Gas Oil  429  42.9%  0  0.0%
Resid/HFO  SB  8.6%  86  7.9%
Total  1000  100.0%  1089  100.0%