We'll be bouncing around a bit in this dispatch, and are including a number of links and excerpts. And, we'll hopefully have it organized in such a way that it won't be too confusing.
First, we've reported and documented many times that Coal can be gasified with Steam, i.e., H2O, and, be made thereby to yield a blend of Carbon Monoxide and elemental, molecular Hydrogen, H2; a combination of gases commonly known as "synthesis gas", or "syngas", which can be subsequently reacted together, through the action of a catalyst, and be made thereby to form a variety of gaseous and liquid hydrocarbons.
One of our expositions of such technology is accessible via:
Exxon Coal + CO2 + H2O Combo Gasification & Conversion | Research & Development; which discusses: "United States Patent 4,318,712 - Catalytic Coal Gasification Process; 1982; Exxon Research and Engineering; A process for the catalytic steam gasification of coal .... (which entails) the reaction of steam, hydrogen, carbon dioxide, or a similar gasification agent with (carbon)";
and, we urge you to note that Carbon Dioxide, reclaimed from whatever source, can be recycled into such reactions to supplement the supply of Carbon provided by Coal.
Note, too, that, in the process of "US Patent 4,318,712", some molecular Hydrogen is specified to be added to the mix of reactants, to supplement the Hydrogen provided by Steam, even though Hydrogen is also one of the products of the reaction. That Hydrogen is needed as well to help forestall the full oxidation of Carbon, into Carbon Dioxide; and, it is so effective in doing so that, as noted, CO2 from an external source can be added to the process, and be chemically reduced into more of the desired Carbon Monoxide.
That Exxon invention is conceptually similar to many others, including some much earlier, such as disclosed for one example in:
Standard Oil 1952 Coal + Steam = Hydrocarbons | Research & Development; concerning: "United States Patent 2,582,710 - Conversion of Carbonaceous Solids into Volatile Products; 1952; Standard Oil Development Company; The present invention relates to the conversion of carbonaceous solids into volatile products (by their) gasification ... with steam (and) the invention is concerned with ... all types of coal (and) cellulose materials";
wherein it was seen that some organic compounds of botanical origin could be gasified along with Coal, to provide both some of the needed Hydrogen and to introduce a note of Carbon recycling and sustainability.
One of the issues most often left unacknowledged by expositions of such intriguing indirect Coal conversion processes is that the "partial oxidation" of the Coal, and other organic material, which reaction can include Steam and Carbon Dioxide to influence the composition of the product synthesis gas, must somehow be supplied with added elemental, molecular Oxygen, in order to support the gasification of the other reactants with exothermic heat energy from the O2-driven Carbon oxidation reactions.
The issue is usually left unmentioned, we believe, since all of the early Coal gasification technologies were simply based on the assumption that plain old air, perhaps compressed to some extent, and injected under force into the gasification chamber, would supply the needed Oxygen to support those oxidation reactions.
The problem with the use of air, which is sometimes specified to be "enriched" with Oxygen, is that it carries a large amount of Nitrogen into the process, with the end result being both a loss of energy efficiency and the co-production of pollutant Nitrogen oxides.
As we touched on briefly in:
Flue Gas to Fertilizer | Research & Development; and, as we intend to better document in the future, China, as a part of her extensive Coal conversion industry development, intends to further process the Nitrogen oxides, through Ammonia, into fertilizer.
Furthermore, it is explained in:
ScienceDirect - Fuel : Solvent extraction of nitrogen compounds from coal liquids; from Japan's "National Research Institute for Pollution and Resources", that "Nitrogen compounds (can be) separated efficiently from coal liquids by solvent extraction with methanol and water" after the hydrocarbon liquids are synthesized, and, that those "Nitrogen compounds" can include substances of some commercial value, "such as quinoline and indole".
It is likely, however, that the overall indirect Coal conversion process could be made more efficient, and more productive of the more desired hydrocarbons, if Nitrogen could be excluded from the initial step of Steam gasification, with or without, as in the above-noted Exxon process of United States Patent 4,318,712, the inclusion of added Carbon Dioxide.
And, that is the essential feature of the technology disclosed by the United States Patent accessed via the initial link in this dispatch. Pure Oxygen, as opposed to Air, is utilized to support and effect a more efficient partial oxidation of Coal and Steam, into a more pure blend of Hydrogen-Carbon Monoxide synthesis gas, in a process which can be controlled so as to, in addition to eliminating oxides of Nitrogen, also, if wanted, reduce to a large extent any co-production of Carbon Dioxide.
Comment and additional references follow excerpts from that initial link to:
"United States Patent 6,997,965 - Method for the Gasification of Coal
Date: February, 2006
Inventor: Yukuo Katayama, Japan
Assignee: Toyo Engineering Corporation
Abstract: A method of the gasification of coal using oxygen and steam is provided wherein the coal is gasified at a temperature of from 1000 to 2500C ... using oxygen generated by electrolyzing water and steam having a temperature of from 300 to 600C attained by heat exchange heat with a high temperature gas generated by the coal gasification. In the method, a remarkably higher efficiency and low carbon dioxide emission is attained.
(First of all, we must interject here that "electrolyzing water", as above, would not only produce the Oxygen they want, but, would, as demonstrated in:
Germany Makes Economical Hydrogen from H2O | Research & Development; concerning: "United States Patent Application 20090026089 - System and Method for Splitting Water; 2009; Hermsdorfer Institut, Germany; The present invention relates to a system and a method for cleaving water ... into hydrogen and oxygen";
as well produce Hydrogen, as could be used in the above-noted Exxon process of US Patent 4,318,712, to help in the hydro-gasification of Coal, and to enable, in that Exxon process, the consumption and use of added Carbon Dioxide.)
Claims: A method for gasification of coal using steam, wherein the coal is gasified at a temperature of from 1000 to 2500C ... using steam (and) wherein oxygen is introduced in (a specified) amount ... .
(And) wherein hydrogen is introduced in (a specified) amount ... .
(And) wherein the electrolysis of water is carried out using electric power generated by wind power, water power, or solar energy.
(Or, we submit, that, as seen in:
Another Energy Bonanza for Coal Country | Research & Development; concerning: "West Virginia Geothermal; A Large Green Energy Source Beneath Northeastern West Virginia; New research ... suggests that the temperature of the Earth beneath the state of West Virginia is significantly higher than previously estimated and capable of supporting commercial baseload geothermal energy production (to generate) heat and electricity";
the electrolysis of water, to produce both the Oxygen required herein, and additional Hydrogen, could be accomplished by electricity generated by a Coal Country energy resource almost no one knows about, but which we do have available to us.)
(And) wherein at least a sufficient amount of oxygen or at least sufficient amounts of oxygen and hydrogen for (the) 24 hour operation of coal gasification is produced in the electrolysis of water.
Background and Field: The present invention relates to a method for the gasification of coal, more specifically to a method for the gasification of coal wherein electric power generated by wind power, waterpower or solar energy can be effectively utilized.
Summary: The present invention provides a method for the gasification of coal wherein a remarkably higher efficiency is attained and very clean gas is produced with extremely low carbon dioxide emission.
The present inventor has directed attention to the facts that, in the conventional partial oxidation gasification, the oxygen is produced by air separation using electric power or steam generated by burning a part of feed coal, which results in a low efficiency of producing clean gas and an increased amount of carbon dioxide emission. After an intensive study, the present inventor has found that a remarkably higher efficiency and higher heating value of a gas obtained by gasification can be achieved with very low carbon dioxide emission by producing oxygen by water electrolysis ... and, in a first aspect of the invention, by mixing hydrogen produced by the water electrolysis with a gas produced by gasification.
Also it has been found in a second aspect of the invention that clean gas having a higher heating value can be produced with a remarkably higher efficiency as well as a very low carbon dioxide by utilizing water electrolysis to produce oxygen and hydrogen and producing high-temperature steam from the oxygen and the hydrogen produced by the water electrolysis. Particularly, utilizing renewable energy for the water electrolysis, such as wind power, waterpower, and the solar energy, can significantly increase economical efficiency.
(An inefficiency we perceive herein is that they propose to reconvert some of the O2 and H2 they derive by water electrolysis back into Steam for use in the initial gasification. If Steam is needed, we think there better ways to go about getting it; and, if there is so much H2 floating around that we can afford to do without some of it in the process of our current invention, then, we suggest it could be better utilized by being directed into a separate process such as that described in:
WVU Hydrogenates Coal Tar | Research & Development; concerning: "Hydrogenation of Naphthalene and Coal Tar Distillate; West Virginia University; 2009; Abstract: The hydrogenation of naphthalene and coal-tar distillates has been carried out in a Trickle Bed Reactor, in which the liquid is allowed to flow through the catalyst bed in the presence of hydrogen (to form) the hydrogenated product, tetralin (which enables) the conversion of coal to refinable crude hydrocarbons, from which liquid fuels such as gasoline, diesel, kerosene, etc., can be produced".)
According to the present invention, clean energy is produced from coal which emits about 1.3 times as much CO2 as petroleum does, by using the solar energy, wind power, or waterpower (or geothermal energy, as suggested above) to electrolyze water, and gasifying coal using oxygen and hydrogen produced by the electrolysis of water.
The produced energy is accompanied with CO2 emission ... almost the same as that of petroleum, and a heat value ... 121% of that of the feed coal. This means that about 4600 Kcal of renewable energy per kg of coal is taken in the product gas and, therefore, the present method of the coal gasification is more harmless to the global environment than conventional gasification,
The product gas of the present gasification contains so much as 55% of hydrogen or more. This product gas can be used for producing methanol."
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Which Methanol, we remind you, can then, as seen in:
Mobil Oil Coal to Methanol to Gasoline | Research & Development; concerning "USP 4,447,310 - Production of Distillates through Methanol to Gasoline; 1984; Mobil Oil Corporation;
be further converted into Gasoline.
And, since purified Oxygen, O2, instead of air, is required herein by Japan's process of United States Patent 6,997,965, to make a Nitrogen Oxide-free Methanol synthesis gas from Steam and Coal, here's an intriguing way we can obtain that Oxygen, aside from the electrolysis of Water:
"Process of producing oxygen - United States Patent 2,490,986
Date: December 13, 1949
Inventor: Fred Symonds, Indiana
Assignee: Standard Oil Company, Chicago
This invention relates to an apparatus for conducting chemical reactions in the gas phase in the presence of finely divided, fluidized solids. The solids may act as catalysts to accelerate a chemical reaction involving one or more gases or vapors, or the solids may take part in the reaction ... .
The process is especially applicable to making oxygen, particularly to the manufacture of industrial oxygen.
The use of my fluid flow furnace offers a method for making industrial oxygen more cheaply than has been possible heretofore.
(The) oxygen produced will contain from 5 to 25% of CO2 (but) may be employed without removal of the CO2, ... in the Fischer process for preparing synthesis gas. In (that) reaction, the oxygen is used to maintain the temperature of the gas maker (and) any CO2 contained in the oxygen is converted to CO (carbon monoxide) by the fuel employed, be it coke ... or other suitable carbonaceous material.
The process of making oxygen from air which comprises contacting in an absorption zone at an elevated temperature a (specified) fluidized oxygen absorbent material comprised of a dissociable (metal oxide), continuously transferring a stream of absorbent material charged with oxygen and substantially free of nitrogen to an oxygen liberation zone maintained at an oxygen liberation temperature substantially higher than the temperature of said absorbing zone ... .
Where the gas is desired for methanol synthesis ... the gas preparation converter may be operated (so as) to allow carbon dioxide to remain unreduced in the product gases and the carbon dioxide can be converted to methanol in the methanol synthesis step".
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Essentially, they are just cycling one of a number of specified metal oxides, capable of different levels of oxidation, through two connected zones, where those metal oxides sequentially first absorb Oxygen from the atmosphere, and, then, discharge it into the Coal hydro-gasification process.
And, we are confident, that, as in "carbon dioxide can be converted to methanol in the methanol synthesis step", the same amount of Carbon Dioxide would be acceptable in our initial subject "United States Patent 6,997,965 - Method for the Gasification of Coal", wherein a "method of the gasification of coal using oxygen and steam is provided" and, which method generates a "product gas" which, too, "can be used for producing methanol".
In sum, and so we don't lose track of the point:
If we are going to make a synthesis gas suitable for the efficient production of liquid hydrocarbons by reacting Coal with Carbon Dioxide and Steam; and, according to "United States Patent 6,997,965 - Method for the Gasification of Coal", as herein, we can certainly do so, then we'll need a little Oxygen to help keep that gasification reaction going.
According to "United States Patent 2,490,986 - Process of Producing Oxygen", again as herein, we can rather directly obtain that needed Oxygen, "cheaply", in a continuous process based on passing an Oxygen carrier through zones of varying temperatures, which could take advantage of the exothermic heat generated by the initial Coal gasification process of "United States Patent 6,997,965".