Herein, from that great greaser of sub-tropic American seas, and US coastlines and beaches, we submit an interesting refinement on the art of indirect Coal liquefaction; one that takes advantage of the fact that processes for the initial gasification of Coal most often co-generate a certain amount of Carbon Dioxide, along with the more-desired Carbon Monoxide and Hydrogen components of hydrocarbon synthesis gas.
Please note that our headline is not entirely accurate, since the technology we make report of is one which generates both alcohols and hydrocarbons from syngas which contains Carbon Dioxide.
We remind you, too, that, as we've several times documented, as for one instance in our report of:
Texaco 1953 CO2-Free Coal Syngas | Research & Development; concerning, primarily: "United States Patent 2,655,443 - Synthesis Gas Generation; 1953; The Texas Company (Texaco); This invention relates to a process and apparatus for the generation of ... a mixture of carbon monoxide and hydrogen, suitable as a feed for the synthesis of hydrocarbons, from powdered coal. In the gasification of carbonaceous material with oxygen, particularly solid fuels, the reaction between the oxygen and the fuel results in the production of carbon dioxide according to the equation: C + O2 = CO2. The oxidation reaction, being highly exothermic, releases large quantities of heat. The carbon dioxide, so produced, in contact with hot carbon, in turn reacts with the carbon to produce carbon monoxide: CO2 + C = 2CO. Steam also reacts with heated carbon to produce carbon monoxide and hydrogen: H2O + C = CO + H2";
it is perfectly feasible to structure a Coal gasification reaction so that any Carbon Dioxide, which might be or is co-produced with the desired Hydrogen and Carbon Monoxide, can be made to, as an integral part of the process and reaction sequence, react with the heated Carbon in the Coal to form more Carbon Monoxide.
So effective is that C + CO2 = 2CO Carbon Dioxide chemical reduction reaction, in fact, that, we think dramatically, condensed liquid Carbon Dioxide, recovered from whatever source, can, as we documented in:
Conoco 2011 Coal + CO2 + H2O + O2 = Syngas | Research & Development; concerning: "United States Patent 7,959,829 - Gasification System and Process; 2011; ConocoPhillips Company; Abstract: A system and process for gasifying carbonaceous feedstock with staged slurry addition in order to prevent the formation of tar that causes deposition problems. Dry solid carbonaceous material is partially combusted, then pyrolyzed along with a first slurry stream comprising carbonaceous material (and) wherein (the) carrier liquid (for the Coal) is selected from group consisting of water (and) liquid Carbon Dioxide";
actually be used to carry and convey ground-up Coal into the gasification reaction.
However, there is, according to British Petroleum, another way to utilize any Carbon Dioxide that might be co-generated in more "conventional" sorts of Coal gasification processes that produce a feed gas for the synthesis of hydrocarbons and which contain some Carbon Dioxide, and, a way of dealing with any Carbon Dioxide that might be co-produced when the Carbon Monoxide and Hydrogen synthesis gas blend is catalytically condensed into hydrocarbons; a way which is actually simpler in concept and results in the production of a broader array of valuable materials.
First, keep in mind that, as we've documented, for example, in:
Pittsburgh 1931 CO2 to Methanol | Research & Development; concerning: "US Patent 1,831,179 - Producing Reduction Products of Carbon Dioxide; 1931; Assignee: The Selden Company, Pittsburgh; The invention relates to the process of preparing reduction products of carbon dioxide. More particularly, this invention relates to the catalytic reduction of carbon dioxide in the presence of hydrogen or hydrogen containing gases and catalysts"; and, in:
Conoco Converts CO2 to Methanol and Dimethyl Ether | Research & Development; concerning: "United States Patent 6,664,207 - Catalyst for Converting Carbon Dioxide to Oxygenates; 2003; Assignee: ConocoPhillips Company, Houston; A catalyst and process for converting carbon dioxide into ... methanol and dimethyl ether";
we've known for quite awhile how to catalytically react Carbon Dioxide with Hydrogen to synthesize alcohols, and, we're continuing to improve the efficiency of those processes.
That's of moderate importance since, even though, as in the above-cited Texaco process of "United States Patent 2,655,443 - Synthesis Gas Generation", we can generate a hydrocarbon synthesis gas from Coal that is itself essentially free of Carbon Dioxide, we note again that some, relatively minor, amount of CO2 is generated as a by-product in the catalytic reactions, such as the venerable Fischer-Tropsch process, which condense blends of Carbon Monoxide and Hydrogen synthesis gas into liquid and gaseous hydrocarbons.
British Petroleum tales advantage of all those facts in their invention for synthesizing both hydrocarbons and alcohols, in a coupled and integrated sequence of processes, from what we might describe as a "typical", or conventional, syngas derived from Coal.
As seen, with comment inserted and appended, in our excerpts from the initial link in this dispatch to:
"United States Patent 6,903,140 - Fischer-Tropsch Process
Date: June, 2005
Inventors: Josephus Font-Freide, et. al., Great Britain
Assignee: BP Exploration Operating Company, et. al., London
Abstract: Process for the conversion of synthesis gas to a product comprising liquid hydrocarbons and oxygenates. The process includes contacting synthesis gas at an elevated temperature and pressure with a mixed particulate catalyst comprising a mixture of a particulate Fischer-Tropsch catalyst and a particulate oxygenate synthesis catalyst.
(Keep in mind that, by "oxygenates", they mean "oxygenated hydrocarbons", i.e., alcohols.)
Claims: A process for the conversion of synthesis gas to a product comprising liquid hydrocarbons and methanol, wherein said process comprises contacting synthesis gas at an elevated temperature and pressure with a suspension of mixed particulate catalyst comprising a mixture of a particulate Fischer-Tropsch catalyst and a particulate methanol synthesis catalyst suspended in a liquid medium in a reactor system comprising at least one high shear mixing zone and a reactor vessel, the process comprising:
a) passing the suspension through a said high shear mixing zone(s) where the synthesis gas is mixed with the suspension;
b) discharging a mixture comprising the synthesis gas and the suspension from the high shear mixing zone into the reactor vessel; and:
c) converting the synthesis gas to liquid hydrocarbons and methanol in the reactor vessel to form a product suspension comprising the mixed particulate catalyst ... , liquid hydrocarbons and methanol; wherein the product suspension is, at least in part, recycled to the high shear mixing zone(s).
A process ... wherein the Fischer-Tropsch reaction is preferably carried out at a temperature of 180-280C and at a pressure of 5-50 bar.
(The reaction conditions are not that extreme, or "severe". They are well within the established realms of practical chemical and industrial engineering.)
A process ... wherein the ratio of hydrogen to carbon monoxide in the synthesis gas is in the range of 20:1 to 0.1:1 by volume.
(In other words, we don't have to be too careful or precise in the way we make the syngas; and, it could thus be generated from a variety of sources, including all grades of Coal and otherwise waste, Carbon-recycling organic material. A suitable process for preparing the synthesis gas utilized herein by British Petroleum could be one such as that disclosed in our report of:
Exxon Co-Gasifies Coal and Carbon-Recycling Biomass | Research & Development; concerning: "US Patent Application 20100083575 - Co-gasification Process for Hydrocarbon Solids and Biomass; 2010; Assignee: ExxonMobil Research and Engineering Company;A process for the co-gasification of carbonaceous solids (coal) and biomass".)
A process ... wherein the synthesis gas comprises 5 to 40% by volume of carbon dioxide.
(We must emphasize the above claim. A "synthesis gas" suitable for producing "liquid hydrocarbons and methanol", in this British Petroleum process, can consist of up "to 40% by volume of carbon dioxide". That seems at least modestly significant to us.)
A process ... wherein the ratio of Fischer-Tropsch catalyst to methanol synthesis catalyst is usually in the range of 20:1 to 1:10 by weight (and) wherein the Fischer-Tropsch catalyst is cobalt supported on zinc oxide (and) wherein the methanol synthesis catalyst is copper supported on zinc oxide.
(Note: There is absolutely nothing exotic or hugely expensive in the catalyst compositions; and, the variances allowed in the ratios of the Fischer-Tropsch catalyst to Methanol catalyst suggests that we don't have to spend a lot of money on the precise formulation and manufacturing of them.)
Background and Description: The present invention relates to a process for the conversion of carbon monoxide and hydrogen (synthesis gas) to liquid hydrocarbon products and methanol in the presence of a particulate catalyst.
In the Fischer-Tropsch reaction synthesis gas is reacted in the presence of a heterogeneous catalyst to give a hydrocarbon mixture having a relatively broad molecular weight distribution. This product comprises predominantly straight chain saturated hydrocarbons which typically have a chain length of more than 5 carbon atoms. Similarly synthesis gas may be reacted in the presence of a heterogeneous catalyst to give oxygenates e.g. methanol or dimethyl ether.
(The above "dimethyl ether", or "DME", as we've noted in several previous reports, can serve as an acceptable substitute even for Diesel fuel. It can also serve, as can Methanol, as a raw material for further conversion processes, such as documented in:
ExxonMobil Coal to Methanol to Gasoline | Research & Development; wherein is reported, among others:
"United States Patent 4,035,430 - Conversion of Methanol to Gasoline; 1977; Assignee: Mobil Oil Corporation; Abstract: The conversion of methanol to gasoline";
and, we'll make a point of documenting the Gasoline conversion potentials of DME specifically in a separate report soon to follow in coming days.)
Summary: It has now been found that the oxygenate synthesis reaction and the Fischer-Tropsch synthesis reaction can be combined and the combined process provides a significant increase in synthesis gas conversion compared with a conventional Fischer-Tropsch process.
The combined process also consumes at least a part of the carbon dioxide which may be present in the synthesis gas or which may be a by-product of the Fischer-Tropsch process.
Accordingly the present invention provides a process for the conversion of synthesis gas to a product comprising liquid hydrocarbons and oxygenates wherein said process comprises contacting synthesis gas at an elevated temperature and pressure with a mixed particulate catalyst comprising a mixture of a particulate Fischer-Tropsch catalyst and a particulate oxygenate synthesis catalyst.
The synthesis gas may be prepared using any of the processes known in the art ... .
(We again suggest, as one of the more exemplary syngas preparation "processes known in the art", our above-cited ExxonMobil process of "US Patent Application 20100083575 - Co-gasification Process for Hydrocarbon Solids and Biomass".)
An advantage of the process of the present invention is that carbon dioxide is consumed in the process ...
(Quite a significant "advantage", we would think.)
(Another) advantage of the process of the present invention is that the oxygenates generated in the process may react with the carbon dioxide present in the synthesis gas as well as the carbon monoxide and hydrogen to form liquid hydrocarbon products.
(And) the mixed particulate catalyst produces both methanol and liquid hydrocarbons."
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Note that the Methanol produced by the process, from, in part, Carbon Dioxide, can be made to react with even more Carbon Dioxide, and more Carbon Monoxide and Hydrogen, to form more hydrocarbons.
We believe such a process is called "homologation", and, we had at least intended, more than a year ago, to make some reports about it's potentials. A computer meltdown at that time might have prevented our doing so; and, we will attempt to readdress such technologies for further utilizing Carbon Dioxide in the future.
But, perhaps of crucial importance herein, is the fact that all, or very nearly all, of the Carbon Dioxide which might be generated by this process is utilized in the process for the synthesis of hydrocarbons and alcohols.
Further, if a process for the generation of the initial synthesis gas is one such as the above-cited:
"United States Patent Application 20100083575 - Co-gasification Process for Hydrocarbon Solids and Biomass; 2010; ExxonMobil Research and Engineering Company; A process for the co-gasification of carbonaceous solids (coal) and biomass";
then, the liquid fuels synthesized by the CO2 emission-free British Petroleum process herein, of "United States Patent 6,903,140", formed as they would be from synthesis gas generated from both Coal and Carbon Dioxide-recycling "biomass", should have no problem, whatsoever, in meeting the specious and obstructionist requirements of Section 526 of the Energy Independence and Security Act of 2007.
For more on that issue, we refer you to our recent report of:
Florida Congressman Seeks Repeal of Anti-Coal Liquefaction Law | Research & Development.
And, since our own United States Department of Energy confessed, as seen in:
USDOE Says Coal Liquefaction Economically Viable Now | Research & Development; where: "Richard Bajura, director of the National Research Center for Coal and Energy at West Virginia University", a presumably knowledgeable and credentialed source, is recorded as having said "liquid coal could be produced for $60 to $70 a barrel";
That: liquid hydrocarbon fuels made from Coal are, right now, economically more than competitive with those made from natural petroleum, even aside from the extraordinary indirect costs incurred by the military and other tax-funded government agencies involved in keeping the OPEC and Big Oil spigots of natural petroleum flowing;
Then: there is then no conceivable argument, based on economy or environment, absolutely none, that should prevent us from immediately starting to pursue a path to domestic prosperity and liquid fuel independence based on the conversion of our abundant Coal, and our sustainable, Carbon-recycling wastes, into liquid hydrocarbon fuels.