United States Patent: 7883682
Our headline on this dispatch, "Conoco Captures Coal Syngas CO2 for Hydrocarbon Synthesis", is one which the representatives of the ConocoPhillips Company, should they see it, might dispute.
It is, we confess, an extrapolation. It is not, we insist, an exaggeration.
First, we remind you of a previous report, as accessible via:
West Virginia Coal Association | Big Oil Prepares to Harvest Carbon Dioxide | Research & Development; concerning: "United States Patent Application 20110186441 - Electrolytic Recovery of Retained Carbon Dioxide; 2011; Assignee: ConocoPhillips Company; Abstract: Methods and apparatus relate to capturing carbon dioxide. A solution formed from metal ions combined with an amine reagent absorbs carbon dioxide from gas introduced into the solution. Subsequent electrolysis of the solution results in dissociation of complexes formed upon the carbon dioxide being absorbed. The electrolysis thus liberates the carbon dioxide for capture and regenerates the solution for reuse";
which, as a close read of the full Disclosure will reveal, describes a regenerative chemical system that can extract, and then produce into a concentrated stream, Carbon Dioxide as it might be present in other gas mixtures at percentage concentrations as low as three percent.
We might have mischaracterized that a bit in our report, since that's not quite good enough to extract CO2 from the atmosphere in a practical way.
As can be learned via: Composition of Air; Carbon Dioxide, maybe surprisingly, comprises, by volume, only about 0.033% of the atmosphere, although other estimates we've seen vary, by less than 0.008%, higher; and, all estimates we've seen, as we understand it, confess that the human contribution would be less than that almost miniscule 0.008% variance in estimates.
Maybe we're reading it all wrong. With our varied disabilities and insufficiencies that's certainly a possibility.
But, if not, someone really should do a statistical analysis of the various estimates that are available, calculate the standard deviation, and see if it's all, the human component, really meaningful in any case.
However, as we have previously documented, and as we will further document, regardless of the amount of CO2 in the atmosphere, we can extract it from the air on a practical basis, if we intend to do something constructive with it once we have it.
Herein, though, we see that ConocoPhillips posits extracting Carbon Dioxide from a perhaps more intriguing source, i.e.:
Hydrocarbon synthesis gas that has been generated from Coal, prior to the catalytic chemical condensation of that synthesis gas into hydrocarbons.
And, this is, primarily, the disclosure of one component of a process, developed by ConocoPhillips, one component of a complete system for, first, capturing Carbon Dioxide, and, then, regenerating that CO2 as a concentrated and purified product, in the course of converting Coal into hydrocarbon synthesis gas.
And, we remind you, via reference to one of our previous reports, just why they might want to capture a little purified product Carbon Dioxide. As seen in:
West Virginia Coal Association | 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; Abstract: A catalyst and process for converting carbon dioxide into oxygenates. The catalyst comprises ... copper; zinc; aluminum; gallium; and a solid acid (wherein) said solid acid (comprises) a zeolite (specified as) ZSM-5. A catalyst composition for converting carbon dioxide to methanol and dimethyl ether";
ConocoPhillips know how to convert Carbon Dioxide into not only the Alcohol, Methanol, which can, as in:
Mobil Oil Coal to Methanol to Gasoline | Research & Development; concerning: "United States Patent 4,447,310 - Production of Distillates through Methanol to Gasoline; 1984; Mobil Oil Corporation; A process for producing a wide slate of fuel products from coal is provided by integrating a methanol-to-gasoline conversion process with coal liquefaction and coal gasification. The coal liquefaction comprises contacting the coal with a solvent under supercritical conditions whereby a dense-gas phase solvent extracts from the coal a hydrogen-rich extract which can be upgraded to produce a distillate stream. The remaining coal is gasified under oxidation conditions to produce a synthesis gas which is converted to methanol. The methanol is converted to gasoline by contact with a zeolite catalyst";
be further "converted to gasoline"; but, as well, the versatile substitute Diesel fuel, Dimethyl Ether.
The full Disclosure of our subject ends with the statement:
"The preferred forms of the invention described above are to be used as illustration only, and should not be used in a limiting sense to interpret the scope of the present invention. Obvious modifications to the exemplary embodiments, set forth above, could be readily made by those skilled in the art without departing from the spirit of the present invention. The inventors hereby state their intent to rely on the Doctrine of Equivalents to determine and assess the reasonably fair scope of the present invention as pertains to any apparatus not materially departing from but outside the literal scope of the invention as set forth in the following claims."
So, references to those and similar technologies might lie in "the following claims", an addendum not included in the web-accessible record of this patent, claims perhaps indicating the uses to which Carbon Dioxide can be put, Carbon Dioxide captured and concentrated by a process and technology as disclosed by the ConocoPhillips Company in excerpts, with comment inserted and appended, from the initial link in this dispatch to:
"United States Patent 7,883,682 - Carbon Dioxide Rich Off-Gas from a Two-Stage Gasification Process
(Carbon dioxide rich off-gas from a two stage gasification process - ConocoPhillips Company)
Date: February, 2011
Inventors: Roland Schmidt and Robert Morton, OK
Assignee: ConocoPhillips Company, TX
Abstract: A process for gasification is provided for a non-catalytic, two-stage gasification process for gasification of a carbonaceous material. The reactor system generally comprises combustion in a first reaction zone and combustion in a second reaction zone.
(We remind you Conoco have established their own "two-stage gasification" processes for Coal, and other things, as seen, for one perhaps intriguing example, in our report of:
West Virginia Coal Association | Conoco 2011 Coal + CO2 + H2O + O2 = Syngas | Research & Development; concerning: "United States Patent 7,959,829 - Gasification System and Process; 2011; Assignee: ConocoPhillips Company; Abstract: A system and process for gasifying carbonaceous feedstock with staged slurry addition ... . Dry solid carbonaceous material is partially combusted, then pyrolyzed along with a first slurry stream comprising carbonaceous material in two separate reactor sections, thereby producing mixture products comprising synthesis gas. The second slurry stream comprising particulate carbonaceous material is fed to a drying unit downstream of a heat recovery zone along with the mixture product exiting the heat recovery zone. A process for gasification of a carbonaceous material ... wherein said carrier liquid is selected from group consisting of water, liquid Carbon Dioxide, (or) mixtures thereof (and) wherein said particulate carbonaceous material is ... coal, lignite, ... and mixtures thereof. The process is applicable to any particulate carbonaceous material. Preferably, however, the particulate carbonaceous material is coal which, without limitation, includes lignite, bituminous coal, sub-bituminous coal, or any combination thereof. Additional carbonaceous materials are coke from coal, coal char, coal liquefaction residues, particulate carbon, ... biomass, concentrated sewer sludge, bits of garbage, rubber and mixtures thereof.")
Claims: A non-catalytic two-stage process for gasification of a carbonaceous material, which process comprises the steps of:
(a) combusting in a first reaction zone a stream comprising an oxygen-containing gas and a first feedstock comprising of a slurry of particulate carbonaceous material in a liquid carrier at a temperature of between 2400F and 300F and at a pressure of from 50 psig ... to 600 psig, thereby evolving heat and forming a first reaction product comprising liquid, molten slag and a gaseous products stream and entrained byproduct sticky, molten slag particles;
(b) separating out and removing said liquid and molten slag;
(c) combusting, in a second reaction zone a stream comprising an oxygen-containing gas, and a second feedstock comprising that portion of said first reaction product which comprises said gaseous products stream and said entrained byproduct sticky, molten slag particles and a second increment of a slurry of particulate carbonaceous material in a liquid carrier, at (the specified temperatures and pressures) thereby evolving heat and forming a second reaction product comprising liquid, molten slag and a gaseous products stream and entrained byproduct sticky, molten slag particles, and a stream of predominately carbon dioxide;
(d) recovering a second portion of the heat from said gaseous products stream of the second reaction product in a high temperature heat recovery system, including a fire-tube boiler, whereby the gaseous products are cooled to a temperature of about 450F to about 550F; and:
(e) recovering said stream of predominately carbon dioxide.
The process ... wherein the carrier liquid is water.
The process ... wherein said slurry of said steps (a) and (c) have a solids concentration from 30 to 70 percent by weight.
The process ... wherein the oxygen-containing gas selected from the group consisting of oxygen, oxygen-enriched air, and mixtures thereof.
The process ... wherein said carbonaceous material is coal or lignite.
The process ... wherein said second reaction zone is connected to the top of said first reaction zone.
The process ... wherein said stream of predominately carbon dioxide is cooled and recycled into the first reaction zone.
(The above claim could be as in our above citation of "United States Patent 7,959,829 - Gasification System and Process", wherein a blend of Coal and Carbon Dioxide can be fed into the gasifier. Another example of Carbon Dioxide use in an initial Coal gasification can be seen in our report of:
Shell Oil Coal + CO2 + H2O = Hydrocarbon Syngas | Research & Development; concerning: "United States Patent 7,829,601 - Partial Oxidation Process of a Solid Carbonaceous Feed; 2010; Assignee: Shell Oil Company, Texas; Abstract: The invention is directed to a process for preparing a mixture comprising CO and H2 by operating a partial oxidation process of a solid carbonaceous feed, which process comprises the steps of: (Supplying) the solid carbonaceous feed and an oxygen-containing stream to a burner, wherein a CO2 containing transport gas is used to transport the solid carbonaceous feed to the burner".)
The process ... wherein said stream said stream of predominately carbon dioxide is sequestered.
(In the immediately-above claim, keep in mind that "sequestered" doesn't mean just pumped down a geologic sequestration rat hole to help subsidize Big Oil's secondary scrounging of residual petroleum in natural reservoirs. Carbon Dioxide can also be "sequestered" by encapsulating it in other things, or by chemically incorporating and consuming it in the synthesis and production of other substances. We'll get to that again in our closing comments, after the complete excerpts. - JtM)
Background and Field: This invention relates to the gasification of carbonaceous materials. More particularly, the invention relates to the conversion of a solid carbonaceous fuel into gaseous products having increased fuel value and ease of capture of carbon dioxide by-products.
(Please note that someone, at long last, has begun to mimic our practice of referring to "carbon dioxide" as a "by-product", not a waste or a pollutant.)
Gasification has been used since the early 1800's to produce town gas from coal. Town gas was the most important gaseous fuel during the early industrial revolution and was used mainly for lighting, heating, and cooking. Starting around 1900, gasification was used to produce fuel with equal parts of hydrogen and carbon monoxide. Now, gasification processes can convert coal or coke into syngas, which can be ... a starting point in many chemical processes.
Gasification reactors can convert generally solid feedstocks into gaseous products. For example, gasification reactors can gasify carbonaceous feedstocks, such as coal ... to produce desirable gaseous products such as hydrogen. Gasification reactors must be constructed to withstand the significant pressures and temperatures required to gasify solid feedstocks.
Generally, carbon in the coal ... can be converted into gas by partial combustion with oxygen, according to the following equations. C + O2 = CO2 and C + 1/2O2 =.CO.
Carbon also can react with water in an endothermic water gas reaction. C + H2O = CO + H2.
The shift reaction can convert all or part of the carbon monoxide into hydrogen to reach equilibrium:
CO + H2O = CO2 + H2,
The final mixture which comprises hydrogen and carbon monoxide is called syngas.
The second reaction zone can promote additional combustion which does not occur in the first reactor. The second feedstock can be injected into the second reaction zone by any means known in the art to provide a good reaction. Thus, both the fired reaction zone one and the fired reaction zone two reactor are primarily combustion reactors.
Detailed Description: The present invention provides a two-stage, oxy-fired, non-catalytic gasification process for gasification of carbonaceous materials. The reactor system generally comprises oxy-firing in a first reaction zone and oxy-firing in a second reaction zone. As used herein, the term "oxy-firing" denotes combustion in the presence of greater than about 80 volume percent oxygen, as O2, preferably greater than about 90 volume percent oxygen, and most preferably greater than 95 volume percent oxygen. Even though such a two-stage, oxy-fired, non-catalytic gasification process for gasification of carbonaceous materials can require additional oxygen feed, it is believed that the equipment necessary to produce any needed additional oxygen will be far more cost effective and more easily operated and maintained that any type of amine separation unit.
The first feedstock for and into the first reaction zone can comprise coal and/or water and other fluids to generate a coal ... slurry for more ready flow and combustion.
When the first feedstock comprises coal ... the first reaction product can comprise steam, char, and gaseous combustion products such as hydrogen, carbon monoxide, and carbon dioxide. The first reaction product also can comprise slag, as discussed in more detail below.
The first reaction product can be separated into an overhead portion and underflow portion. For example, where the first reaction product comprises steam, char, and gaseous combustion products, the overhead portion of the first reaction product can comprise steam and the gaseous combustion products while the underflow portion of the first reaction product can comprise slag. "Slag," as used herein, refers to mineral matter from the first feedstock along with any added residual fluxing agent, if any, that can remain after gasification reactions that occur within the first reaction zone and/or second reaction zone. The overhead portion of the first reaction product can be introduced into the second reaction zone.
The second feedstock for and introduced into the second reaction zone can comprise the overhead portion of the first reaction product. The second feedstock can further comprise additional coal ..., water and other fluids to generate a ... slurry for more ready flow and combustion.
The second feedstock also can further comprise carbon dioxide which has been recovered and recycled after exiting the second stage reaction zone. Optionally, the recovered and recycled carbon dioxide can be cooled to assist in temperature control of the second reaction zone.
(Again, CO2, in reaction with hot Carbon, will form more of the desired Carbon Monoxide.)
The second reaction product can similarly comprise steam, char, and gaseous combustion products such as hydrogen, carbon monoxide, and carbon dioxide when the first feedstock comprises coal ... . The second reaction product also can comprise slag.
The gaseous off-gases of the second reaction product can comprise CO2 and steam, which can easily be separated, if desired. If separated, the steam can be condensed and recycled back into reaction zone one, reaction zone two, or both reaction zones one and two. The fairly pure CO2 stream can be sequestered, using any type of carbon capture sequestration (CCS) method known in the art, without the necessity of further purification. Thus, the need for one or more amine separator units to provide amine scrubbing of any off-gasses is no longer necessary with the use of oxy-firing.
The reaction of the first or second feedstocks in the corresponding reaction zone also can produce char. "Char," as used herein, refers to unburned carbon and ash particles that can remain entrained within the first reaction zone and/or second reaction zone after production of the various reaction products. The char produced by reaction of the first feedstock can be removed and recycled either back into the first reaction zone or directly into the second reaction zone to increase carbon conversion."
----------------------------
And, that's pretty much it. A large portion of any by-product Carbon Dioxide is recycled through the dual gasification chambers, where it can react with the Coal and be converted into more of the desired Carbon Monoxide component of hydrocarbon synthesis gas, which, as in the above-cited "United States Patent 4,447,310 - Production of Distillates through Methanol to Gasoline; 1984; Mobil Oil Corporation", be converted into such seemingly-desirable things as "methanol" and "gasoline".
We note again that the initial gasification could be operating a process like that disclosed in the above-cited "United States Patent 7,959,829 - Gasification System and Process; 2011; Assignee: ConocoPhillips Company; Abstract: A process for gasification of a carbonaceous material ... wherein said carrier liquid is selected from group consisting of water, liquid Carbon Dioxide, (or) mixtures thereof (and) wherein said particulate carbonaceous material is ... coal, lignite, ... and ... biomass, concentrated sewer sludge, bits of garbage, rubber and mixtures thereof";
where the CO2-recycling nature of the Coal gasification process would be indirectly enhanced.
And, any excess Carbon Dioxide which couldn't be utilized in that initial gasification, since there would necessarily be some, to avoid material imbalances, could be, since it is recovered as a "fairly pure CO2 stream", be directed to a process like that of the above-cited ConocoPhillips process of "United States Patent 6,664,207 - Catalyst for Converting Carbon Dioxide to Oxygenates", and be converted therein "to methanol and dimethyl ether"; or, to another, closely-related and perhaps more advanced process, as in:
West Virginia Coal Association | ConocoPhillips Recycles Even More CO2 | Research & Development; concerning: United States Patent 7,273,893 - Process for Converting Carbon Dioxide to Oxygenates; 2007; Assignee: ConocoPhillips Company; Abstract: A catalyst and process for converting carbon dioxide into oxygenates.This is a continuation of ... U.S. Pat. No. 6,664,207 ... . A process for converting a carbon dioxide-containing feed into oxygenates, said process comprising the steps of: (a) contacting said carbon dioxide-containing feed with a catalyst composition comprising a solid acid in a reaction zone under reaction conditions sufficient to convert at least a portion of said feed stream into oxygenates, said carbon dioxide-containing feed comprising at least 90 volume percent carbon dioxide and hydrogen, said solid acid comprising a zeolite; and (b) recovering at least a portion of said oxygenates from said reaction zone. The present invention relates generally to the conversion of carbon dioxide ... into methanol and dimethyl ether";
and, again, be converted into the valuable Methanol and Dimethyl Ether.
In essence, as ConocoPhillips themselves put it, the Carbon Dioxide "by-product" of a process like that of our subject, "United States Patent 7,883,682 - Carbon Dioxide Rich Off-Gas from a Two-Stage Gasification Process", which process is designed to produce an essentially CO2-free blend of Carbon Monoxide and Hydrogen synthesis gas, suitable for the catalytic synthesis of liquid hydrocarbons, can to a large degree be recycled and consumed with the process; and, any excess "by-product" Carbon Dioxide can be efficiently recovered as a "fairly pure CO2 stream", which can then be, separately, consumed in the synthesis of even more, other, valuable liquid fuels.
