United States Patent: 7959829

As now accessible on the West Virginia Coal Association's web site via the link:

Texaco 1951 Coal + CO2 + H2O + O2 = Syngas | Research & Development; concerning: "United States Patent 2,558,746 - Carbon Monoxide and Other Gases from Carbonaceous Materials; 1951; The Texas Company, NYC; Abstract: This invention relates to a process and apparatus for the generation of gases comprising carbon monoxide from carbonaceous materials. In one of its more specific aspects it 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. An object of this invention is to provide a process for the generation of carbon monoxide and hydrogen (and) to provide a process particularly suited to the generation of a feed gas for the synthesis of hydrocarbons from coal (in which) carbon dioxide ... reacts with the carbon to produce carbon monoxide (and, wherein steam) also reacts with heated carbon to produce carbon monoxide and hydrogen";

we quite recently documented that Coal gasification reactions, intended to generate a synthesis gas blend of Carbon Monoxide and Hydrogen suitable for catalytic condensation into liquid hydrocarbons, could be designed so that both Steam and Carbon Dioxide can be utilized as agents for such Coal gasification.

Carbon Dioxide would thus be consumed in a process that enables the production of synthesis gas which could be "tailored", as it were, in composition, by adjusting the blends of initial reactants, and thus be made suitable for catalytic condensation into specific and desired ranges of hydrocarbons.

Those essential facts established by Texaco, and officially confirmed by our United States Government, well more than half a century ago, have just very recently been re-established and re-confirmed by, yet again our United States Government, and, yet another major component of the petroleum industry.

And, these more recent developments overcome some of the inefficiencies inherent in earlier Coal gasification processes, such as that disclosed in "United States Patent 2,558,746".

As we attempt to explain, in comment following excerpts from the initial link in this dispatch to the much more contemporary:

"United States Patent 7,959,829 - Gasification System and Process

Date: June, 2011

Inventors: David Breton, et. al., Texas and Oklahoma

Assignee: ConocoPhillips Company, Houston

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 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. The resulting final temperature of the second stage mixture products and dried particulate carbonaceous material is between 450 and 550 F, a temperature range that is typically not conducive to the emission of heavy molecular-weight tar species.

Claims: A process for gasification of a carbonaceous material, comprising the steps of:

a. introducing a dry feedstock comprising recycled char and a solid stream comprising particulate carbonaceous material into a reactor lower section and partially combusting therein with a gas stream comprising an oxygen supply selected from a group consisting of oxygen-containing gas, steam, and mixtures thereof, thereby evolving heat and forming products comprising synthesis gas and molten slag;

b. passing said synthesis gas from said reactor lower section upward into a reactor upper section and pyrolysing therein with a first slurry stream comprising a slurry of particulate carbonaceous material in a liquid carrier, thereby forming mixture products comprising a gaseous product stream comprising synthesis gas and char;

c. passing said mixture products in step (b) through a heat recovery zone;

d. introducing a second slurry stream comprising particulate carbonaceous material in a liquid carrier and said mixture products exiting from said heat recovery zone into a drying unit wherein the water in said second slurry stream is vaporized and said solid stream comprising particulate carbonaceous material is formed;

e. passing said mixture products and said solid stream in step (d) through a separating device, whereby said char and said solid stream are separated from said gaseous product stream;

f. passing said gaseous product stream in step (e) through a particulate filtering device whereby residual solid fines and particulates are separated from said gaseous product stream; and:

g. recycling said dry stock comprising said char and said dried particulate carbonaceous material from step (e) and residual solid fines and particulates from step (f) back to said reactor lower section, whereby said heat evolved in said step (a) is recovered by converting said first slurry stream comprising particulate carbonaceous material in said carrier liquid in step (b) into said gaseous product stream in step (b).

(We'll get to the tasty raw material bits shortly; but, note, in the above, as in other, related Coal conversion technologies we've documented for you, including, for instance:

ExxonMobil Self-Powered Coal Conversion | Research & Development; which includes information about: "United States Patent 3,254,023 - Heat Balancing in Organic Reactions; 1966; Socony Mobil Oil Company;

Abstract: This invention relates to a method of carrying out an exothermic chemical reaction and an endothermic reaction in a single reaction zone wherein the heat evolved in the exothermic reaction is utilized to effect the endothermic reaction"; and:.

1963 Self-Powered Coal Conversion | Research & Development; concerning: "United States Patent 3,107,985 - Coal (and it's) Autogenous Hydrogenation; 1963; Huntington Chemical Company; Abstract: This invention relates to the continuous drying, destructive distillation, gasification and carbonization of coal and other solid carbonaceous material ... (including) ... internal combustion of char to furnish heat for the system, and selective total gasification of the balance of the char";

it has been known for a long time that "a heat recovery zone", as Conoco specifies, can be included in a Coal gasification process, thus enabling the transfer of heat energy from naturally exothermic reactions taking place within the total system, to other reactions that are endothermic and need a supply of energy to be driven forward. The entire system, thus, can be made "energy neutral", relative to the external environment, with no supply of energy needed and with, thus, the attendant economies that implies.)

The process ... wherein said carrier liquid is selected from group consisting of water, liquid Carbon Dioxide, (or) mixtures thereof.

(We must emphasize, that, as immediately above: CO2, in liquid form, recovered from whatever source, can be utilized as a carrier of, and co-reactant with, Coal, in this gasification process technology.)

The process ... wherein said particulate carbonaceous material is ... coal, lignite, ... and mixtures thereof.

Background and Summary: The present invention relates generally to a gasification system and process for converting generally solid feedstock such as carbonaceous material into desirable gaseous products such as synthesis gas.

Three basic types of system and processes have been developed for the gasification of carbonaceous materials. They are: (1) fixed-bed gasification, (2) fluidized-bed gasification, and (3) suspension or entrainment gasification. The present invention relates to the third type of system and process--suspension or entrainment gasification. More particularly, the present invention relates to a two stage entrained gasification system and process for gasifying carbonaceous materials. 

The flexibility of the two stage design can be exploited by maximizing the slurry feed rate to the lower temperature second stage gasifier, thereby utilizing the heat generated from the first stage gasifier to evaporate the water from the slurry. The char and unconverted carbon exiting the second stage gasifier are then separated and recycled back to the first stage gasifier, in a dry form, thus minimizing the amount of oxygen required in the higher temperature first stage and maximizing the conversion efficiency of the gasifier. One problem with feeding to the lower temperature second stage is that the tar produced during the pyrolysis of the coal ... would not be adequately destroyed. The undestroyed tar would condense when the syngas is cooled, thereby fouling the heat exchange surfaces or plugging up the filters downstream.

(Note: Such "tar" is directly comparable and related to the long-known tars and pitches generated in Coke Ovens, and were, as well, generated by earlier Coal gasification processes. The earliest of those Coal gasification operations, and many commercial Coke Ovens, sometimes, sadly, just "dumped" the tars as wastes, although their value in such things as wood preservatives, and as the raw materials from which valuable chemicals, such as aspirin, could be made were recognized early on. Further, it was recognized as well, nearly half a century ago, that, as, for just one instance, in:

 

Consol 1967 Coal Tar to Gasoline | Research & Development; concerning our local Consolidation Coals: "United States Patent 3,355,376 - Hydrocracking of Polynuclear Hydrocarbons; 1967; Consolidation Coal Company; Abstract: Polynuclear aromatic hydrocarbons such as coal extract are hydrogenated in the presence of molten zinc halide catalyst. This invention relates to (a) process for converting polynuclear aromatic hydrocarbonaceous feedstock to gasoline";

such "coal extract"s could be converted into fairly standard types of liquid hydrocarbons; a fact that continued, as in:

USDOE and California Hydrogenate Coal Tars | Research & Development; wherein is reported: "United States Patent 4,101,416 - Process for Hydrogenation of Hydrocarbon Tars; 1978; Occidental Petroleum Corporation; Abstract: Hydrocarbon tars of high asphaltene content such as tars obtained from pyrolysis of coal are dissolved in a solvent formed from the hydrogenation of the coal tars, and the resultant mixture hydrogenated in the presence of a catalyst ... to form a light hydrocarbon as a solvent for the tars. Hydrogen content is at least three times the amount of hydrogen consumed. The government has rights in or in respect of this invention pursuant to Contract N. E(49-18)-2244 awarded by the United States Energy Research and Development Administration. A process for hydrogenation of hydrocarbon tars ... resulting from the coal pyrolysis";

to be reaffirmed all across the nation in following decades. In the case of our subject, "United States Patent 7,959,829 - Gasification System and Process", however, the Coal tars aren't being segregated and separately hydrogenated, but are, instead, being collected and recycled back into the gasification process.

Note that the same is true, as well, of any residual un-gasified carbonaceous "char", which, just as in:

Exxon Gasifies Coal, and Steam-Gasifies the Char | Research & Development; concerning: "United States Patent 5,055,181 - Hydropyrolysis-Gasification of Carbonaceous Material; 1991; Exxon Research and Engineering Company; Abstract: Disclosed is a process for obtaining liquids and gases from carbonaceous material, such as coal. The carbonaceous material is first treated with a gasification catalyst, and optionally a hydrogenation catalyst, and hydropyrolyzed for an effective residence time, below the critical temperature at which methane begins to rapidly form, to make liquid products. The resulting char is gasified in the presence of steam at a temperature from about 500C to about 900C";

can be further treated in an additional gasification process to convert any remaining Carbon into the desired hydrocarbon synthesis gas. In the process of our subject ConocoPhillips technology, of "United States Patent 7,959,829", the further gasification of reclaimed Char is conducted in a gasification chamber somewhat separate from, but still contiguous with, the primary Coal gasification vessel, thus enabling better use of the heat evolved from that primary Coal gasification.)

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."

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And, we'll end our excerpts there, since, in addition to Coal, the "particulate carbonaceous material" which is to be entrained in a "carrier liquid (such as) liquid Carbon Dioxide" for partial combustion in a mixture of an "oxygen-containing gas" and "steam", to form "desirable gaseous products such as" hydrocarbon "synthesis gas", can, again in addition to "lignite, bituminous coal, sub-bituminous coal, or any combination thereof", include "coal liquefaction residues", an admission with what should be obvious implications, and "particulate carbon, ... biomass, concentrated sewer sludge, bits of garbage (and) rubber"; which "biomass", we presume, would include, as it does in the quite similar:

Exxon Co-Gasifies Coal and Carbon-Recycling Biomass | Research & Development; concerning: "United States Patent Application 20100083575 - Co-gasification Process for Hydrocarbon Solids and Biomass; 2010; ExxonMobil Research and Engineering Company; Abstract: A process for the co-gasification of carbonaceous solids (coal) and biomass in which the biomass material ... comprises biological matter selected from wood, plant matter, municipal waste, green waste, byproducts of farming or food processing waste, sewage sludge, black liquor from wood pulp, and algae";

"algae", which, as in ExxonMobil's process immediately above, can, as explained in:

USDOE Algae Recycle CO2 into Liquid Fuels | Research & Development; concerning: " Liquid Fuels from Microalgae; 1987; USDOE; Abstract: The goal of the DOE/SERI Aquatic Species Program is to develop the technology to produce gasoline and diesel fuels from microalgae";

be cultivated and nourished with effluent Carbon Dioxide, then be "harvested", their "lipids"extracted and converted rather directly into "diesel fuels and ... gasoline", and, then, their "cell residue after lipid extraction" directed to another process for further conversion and use, as in both the above-cited process of ExxonMobil's ""United States Patent Application 20100083575", and, that of our subject herein, ConocoPhillips' process of "United States Patent 7,959,829".

And, coincidentally, as those algae were in the process of converting industrial effluent Carbon Dioxide into, essentially, "gasoline and diesel", and, a "cell residue" useful as a co-fed raw material with Coal in our subject Conoco process, they would also, as in:

USDOE Algae Make Hydrogen for Coal and CO2 Hydrogenation | Research & Development; concerning: "Photosynthetic Hydrogen and Oxygen Production by Green Algae; Oak Ridge National Laboratory; 1999;  Abstract: Photosynthesis research at Oak Ridge National Laboratory is focused on hydrogen and oxygen production by green algae";

be producing at least some of the Oxygen required, as in the specified "oxygen-containing gas", by Conoco; and, as well, be co-producing Hydrogen, which could be utilized by adding directly to, and thereby broadening the hydrocarbon product potentials of, the "synthesis gas", made herein by Conoco, out of all sorts of Coal, including "lignite, bituminous coal, sub-bituminous coal, or any combination thereof" and all sorts of renewable and sustainable, Carbon-recycling "biomass, concentrated sewer sludge" and "garbage".


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