United States Patent Application: 0070129450
We've documented for you several times that the well-known Eastman Chemical Company has, for many years now, been operating a Coal gasification factory in Kingsport, Tennessee, where they convert Coal into a hydrocarbon synthesis gas, consisting primarily of Carbon Monoxide and Hydrogen, and then use that syngas to produce the fuel alcohol Methanol and a range of other valuable, industrial chemicals.
Our reports on their Coal conversion operations have included, for example: West Virginia Coal Association | Tennessee Coal to Methanol & Dimethyl Ether | Research & Development; concerning the "US Senate Committee on Energy and Natural Resources; Hearing/Meeting: Oversight on Natural Gas; Full Committee Hearing; July 10, 2003; Witness: Brian Ferguson, Chairman and CEO, Eastman Chemical; Eastman is a pioneer in using coal gasification to produce chemicals. Coal gasification is among the major rational responses to present and foreseeable natural gas shortages and price increases. Coal is the most abundant and price-stable fossil energy resource in the United States. Chemical industry history strongly suggests that abundant and low cost feedstocks, market competition, and stable geopolitics are major factors in technological innovation and economic sustainability. Coal gasification is the coal technology that offers the best opportunity to support environmentally responsible and competitively sustainable basic manufacturing and electricity generation in the United States. ... German chemical industry, throughout the period of 1890 to 1945, focused on development of synthetic products from coal such as synthetic ammonia and gasoline. Coal is the most abundant and price-stable fossil energy resource in the United States. ... Coal gasification is the coal technology that offers the best opportunity to support environmentally responsible and competitively sustainable basic manufacturing and electricity generation in the United States".
More about Eastman's Coal gasification enterprise can be learned from our USDOE, via:
http://www.netl.doe.gov/
And, one aspect of their Coal conversion technology, which we'll be addressing in this report, and in other reports concerning similar developments by others, is represented by:
West Virginia Coal Association | Eastman Coal to Methanol and Electric Power | Research & Development; concerning: "US Patent Application 20060096298 - Method for Satisfying Variable Power Demand; 2006;
(Patent US20060096298 - Method for satisfying variable power demand - Google Patents
Method for satisfying variable power demand - Barnicki, Scott Donald)
Inventor: Scott Barnicki, et. al.; Assignee: Eastman Chemical Company, TN; Abstract: A process for satisfying variable power demand and a method for maximizing the monetary value of a synthesis gas stream are disclosed. One or more synthesis gas streams are produced by gasification of carbonaceous materials and passed to a power producing zone to produce electrical power during a period of peak power demand or to a chemical producing zone to produce chemicals such as, for example, methanol, during a period of off-peak power demand. The power-producing zone and the chemical-production zone which are operated cyclically and substantially out of phase in which one or more of the combustion turbines are shut down during a period of off-peak power demand and the syngas fuel diverted to the chemical producing zone. This out of phase cyclical operational mode allows for the power producing zone to maximize electricity output with the high thermodynamic efficiency and for the chemical producing zone to maximize chemical production with the high stoichiometric efficiency. The economic potential of the combined power and chemical producing zones is enhanced";
wherein the very real potentials for maximizing the value of Coal through the co-production, from Coal, of both electrical power and hydrocarbon chemical synthesis gas at the same industrial facility, in one contiguous and integrated operation, was outlined and defined.
In passing, we'll note, that, as can be learned via:
United States Patent Application: 0060149423: "United States Patent Application 20060149423 - Method for Satisfying Variable Power Demand;
Patent US20060149423 - Method for satisfying variable power demand - Google Patents
Method for satisfying variable power demand - Barnicki, Scott Donald
Date: July 6, 2006
Inventors: Scott Barnicki, et. al., TN
Correspondence (and presumed eventual Assignee of Rights): Eastman Chemical Company, TN
Abstract: A process for satisfying variable power demand and a method for maximizing the monetary value of a synthesis gas stream are disclosed. One or more synthesis gas streams are produced by gasification of carbonaceous materials and passed to a power producing zone to produce electrical power during a period of peak power demand or to a chemical producing zone to produce chemicals such as, for example, methanol, during a period of off-peak power demand. The power-producing zone and the chemical-production zone which are operated cyclically and substantially out of phase in which one or more of the combustion turbines are shut down during a period of off-peak power demand and the syngas fuel diverted to the chemical producing zone. This out of phase cyclical operational mode allows for the power producing zone to maximize electricity output with the high thermodynamic efficiency and for the chemical producing zone to maximize chemical production with the high stoichiometric efficiency. The economic potential of the combined power and chemical producing zones is enhanced";
Eastman has, in fact, been working to further refine and define such technology; and, we haven't made separate report on the above "United States Patent Application 20060149423", since we're not in any way qualified to comment on how it might be differentiated from the nearly-contemporaneous "US Patent Application 20060096298 - Method for Satisfying Variable Power Demand".
We have already reported on similar and related developments by others, and will be addressing them further in reports to follow.
Herein, though, we document how Eastman has refined the process of generating hydrocarbon synthesis gas, "syngas", from Coal, so that it can be made more suitable for use in processes like "US Patent Application 20060096298 - Method for Satisfying Variable Power Demand", for the co-production of both chemicals and, via both combustion and heat exchange, electricity; and, doing so in such a way that the composition of the syngas can be adjusted, on the fly so to speak, to accommodate fluctuations in power demand and to enable changes, as needed in the mix of final products.
As explained more fully in excerpts from the initial link in this dispatch to:
"US Patent Application 20070129450 - Process for Producing Variable Syngas Compositions
Patent US20070129450 - Process for producing variable syngas compositions - Google Patents
Process for producing variable syngas compositions - Barnicki, Scott Donald
Date: June 7, 2007
Inventors: Scott Barnicki, et. al., TN
Correspondence (and presumed eventual Assignee of Rights): Eastman Chemical Company, TN
Abstract: Disclosed is a process for the production of a variable syngas composition by gasification. Two or more raw syngas streams are produced in a gasification zone having at least 2 gasifiers and a portion the raw syngas is passed to a common water gas shift reaction zone to produce at least one shifted syngas stream having an enriched hydrogen content and at least one unshifted syngas stream. The shifted and the unshifted syngas streams are mixed downstream of the water gas shift zone in varying proportions (to) produce blended and unblended synthesis gas streams in a volume and/or composition that may vary over time in response to at least one downstream syngas requirement. The process is useful for supplying syngas from multiple gasifiers for the variable coproduction of electrical power and chemicals across periods of peak and off-peak power demand.
(We've previously reported on the above-mentioned "water gas shift reaction", which can be used in syngas production processes to adjust the ratios of components in the syngas. More can be learned via:
Water gas shift reaction - Wikipedia, the free encyclopedia; "The water gas shift reaction (WGS) is a chemical reaction in which carbon monoxide reacts with water vapor to form CO2 and hydrogen.”)
Claims: A process for producing variable syngas compositions, comprising:
(a) reacting an oxidant stream with a carbonaceous material in a gasification zone comprising at least 2 gasifiers to produce at least 2 raw syngas streams comprising carbon monoxide, hydrogen, carbon dioxide, and sulfur-containing compounds,
(b) passing a portion of at least one of said raw syngas streams from step (a) to a common water-gas shift reaction zone to produce at least one shifted syngas stream (i) having an enriched hydrogen content, and at least one unshifted syngas stream (ii), comprising a remaining portion of said raw syngas streams; and:
(c) blending said shifted syngas stream (i) with a portion of said unshifted syngas stream (ii) to produce at least one blended syngas stream (iii) and at least one unblended syngas stream (iv) comprising a remaining portion of unshifted syngas stream (ii) wherein said blended syngas stream is produced in a volume and/or composition that varies in response to at least one downstream syngas requirement.
The process ... further comprising generating steam in said water-gas shift reaction zone.
The process ... further comprising combining a portion of said steam from said water-gas shift reaction zone with said portion ... of one or more raw syngas streams to produce at least one wet syngas stream and passing said wet syngas stream to said water-gas shift reaction zone.
(A series of claims we're not reproducing concerns the ratios of carbon monoxide and water in the syngas and the recovery of heat from the process. It's also specified that purified Oxygen is to be used in the gasification process, which would result in a "cleaner" product gas mixture free of nitrogen oxides.)
The process ... wherein the carbonaceous material is coal ... .
The process ... further comprising passing each of said syngas streams ... through separate gas cooling zones (and) through separate acid gas removal zones.
The process ... wherein said acid gas removal zones comprise a sulfur removal zone in which at least 95 mole percent of the total of said sulfur containing compounds present in said syngas streams (i) and (ii) or (iii) and (iv) are removed.
(As can be learned in our report of:
West Virginia Coal Association | Georgia Tech By-Product Sulfur from Coal Syngas | Research & Development; concerning: "Title: Electrochemical Polishing of Hydrogen Sulfide from Coal Synthesis Gas; Advanced coal-fired power systems `95 review meeting, Morgantown, WV; June,1995; USDOE Contract: FG22-94PC94207; Research Organization: Georgia Tech Research Institute; Abstract: An advanced process has been developed for the separation of H2S from coal gasification product streams through an electrochemical membrane. H2S is removed from the syngas by reduction to the sulfide ion and Hydrogen at the cathode. The sulfide ion migrates to the anode through a molten salt electrolyte suspended in an inert ceramic matrix. Once at the anode it is oxidized to elemental sulfur and swept away for condensation in an inert gas stream. The syngas is enriched with the H2";
the technologies do exist to effect such Sulfur removal from synthesis gas derived from Coal; technologies which can both enrich the Hydrogen content of the syngas and produce elemental Sulfur as a commercial, cost-offsetting byproduct.)
The process ... wherein said downstream syngas requirement comprises a feedstock need of a least one chemical process, a fuel need of at least one power plant, or a combination thereof (and) further comprising passing said blended syngas stream to a chemical producing zone and said unblended syngas stream to a power producing zone.
The process ... wherein said chemical producing zone produces methanol, alkyl formates, dimethyl ether, oxo aldehydes, ammonia, methane, hydrogen, Fischer-Tropsch products, or a combination thereof (or) wherein said chemical producing zone is a methanol producing zone.
The process ... wherein said power producing zone comprises a combined cycle system (and) wherein said volume and/or composition of said blended syngas stream varies in response to peak and off-peak power demands.
The process ... wherein said blended syngas stream is produced in a volume and/or composition that varies in response to peak and off-peak power demands.
A process for producing variable amounts of power and methanol ... .
(The "methanol", we remind you, as seen for one example in our report of:
West Virginia Coal Association | ExxonMobil "Coal to Clean Gasoline" | Research & Development; concerning: "Coal to Clean Gasoline; ExxonMobil Research and Engineering Company, There are two commercially demonstrated routes for converting coal to transportation fuels through gasification. The widely known Fischer-Tropsch process was first discovered in the 1920s. It has been commercially practiced by Sasol in several different forms ... . Although it is less known, there is another commercially proven alternative for converting coal to gasoline, through methanol. ExxonMobil’s methanol-to-gasoline (MTG) process efficiently converts crude methanol to high quality clean gasoline. When coupled with commercially proven coal gasification and methanol synthesis technology, MTG offers an effective route to premium transportation fuel from coal";
can then be, if desired, converted through known and commercial processes into Gasoline.)
The process ... wherein said 2 or more gasifiers are sized to supply at least 90% of the maximum capacity fuel requirements of said power-producing zone.
Background and Field: This invention relates to a process for the production of two or more synthesis gas streams of variable compositions and volumes. More particularly, this invention relates to a process wherein at least a portion of two or more synthesis gas streams from a gasification zone is passed to a water gas shift zone to enhance its hydrogen content, and the shifted and unshifted streams are mixed downstream of the water gas shift zone to produce at least one blended syngas stream having a volume and/or composition which can vary over time.
The high price and diminishing supply of natural gas and petroleum has caused the chemical and power industry to seek alternative feedstocks for the production of chemicals and the generation of electrical power. Coal and other solid carbonaceous fuels such as, for example, ... biomass, paper pulping wastes, by contrast, are in great abundance and relatively inexpensive, and are logical materials for the art to investigate as alternative feedstock sources. Coal and other solid carbonaceous materials can be gasified, i.e., partially combusted with oxygen, to produce synthesis gas (also referred to hereinafter as "syngas"), which can be cleaned and used to produce a variety of chemicals or burned to generate power.
Different applications, however, require different H2/CO ratios to utilize the syngas raw material efficiently. For example, Fischer-Tropsch and methanol reaction stoichiometries require a 2/1 molar ratio of H2/CO, synthetic natural gas production requires 3/1, acetic acid synthesis requires 1/1, syngas for ammonia or hydrogen production require hydrogen only. This ratio can be adjusted by means known in the art, e.g., via the water gas shift reaction wherein carbon monoxide is reacted with water to produce hydrogen and carbon dioxide. This approach is not satisfactory, however, when there are multiple, different, downstream requirements for syngas. For example, when designing an integrated process to produce syngas with varying H2/CO ratio requirements such as found in chemical and power coproduction facility, one approach is to shift all syngas from a gasification zone to the highest required H2/CO ratio, i.e. overshifting some fraction of the gas. The overshifting approach, however, imparts an energy penalty to those processes not requiring syngas with a high hydrogen to carbon molar ratio. Because the water gas shift reaction is exothermic, a portion of the chemical energy in the syngas (equivalent to the enthalpy of reaction of the water-gas shift reaction) is converted to thermal energy during the shift reaction. Power production, therefore, is maximized by utilizing unshifted gas. For example, shifting to a 2/1H2/CO molar ratio can result in a loss of about 3 (to) 12% of the chemical energy compared to the unshifted gas. The extent of the loss is dependent on the initial H2/CO molar ratio of the syngas. Hence, mole for mole, shifted gas has a lower energy content than unshifted gas.
Summary: We have discovered that multiple syngas streams having a time variant composition and volume can be efficiently produced by using two or more gasifiers to supply raw syngas to a central water gas shift zone, shifting a portion of the raw syngas, and blending the shifted and unshifted gas steams downstream of the water gas shift zone in proper proportions to meet one or more downstream syngas requirements. Accordingly, the present invention provides a process for producing variable syngas compositions, comprising: (a) reacting an oxidant stream with a carbonaceous material in a gasification zone comprising at least 2 gasifiers to produce at least 2 raw syngas streams comprising carbon monoxide, hydrogen, carbon dioxide, and sulfur-containing compounds, (b) passing a portion of at least one of the raw syngas streams from step (a) to a common water-gas shift reaction zone to produce at least one shifted syngas stream (i) having an enriched hydrogen content, and at least one unshifted syngas stream (ii), comprising a remaining portion of the raw syngas streams; and (c) blending the shifted syngas stream (i) with a portion of the unshifted syngas stream (ii) to produce at least one blended syngas stream (iii) and at least one unblended syngas stream (iv) comprising a remaining portion of unshifted syngas stream (ii) wherein the blended syngas stream is produced in a volume and/or composition that varies in response to at least one downstream syngas requirement. The instant invention provides for at least 2 gasifiers connected to a common or shared water gas shift reaction zone in which a portion of the raw syngas from these gasifiers may be directed to produce at least one shifted syngas stream having an enriched hydrogen content and at least one unshifted gas stream comprising the remaining portion of the raw syngas stream. Another aspect of the instant invention is the blending of the shifted syngas stream with all or a portion of the unshifted syngas stream downstream of the gasification zone and water gas shift reaction zone to produce blended and unblended syngas streams. Redundant gas cooling and acid gas removal zones are provided for shifted and unshifted syngas streams of variable composition, consistent with maximum scalable train size, such that the zones can be fed via a syngas header system downstream of the gasification zone and water gas shift reaction zone. The composition of these syngas streams may be varied over time according to at least one downstream syngas requirement such as, for example, a feedstock need of a least one chemical process, a fuel need of at least one power plant, or a combination thereof.
In one embodiment of the invention, for example, the blended syngas stream may be passed to a methanol or dimethyl ether producing zone and the unblended syngas stream passed to a power producing zone to produce electrical power. Steam may be produced from the water gas shift reaction zone by the recovery of heat from the shifted syngas stream and a portion of that steam may be combined with the raw syngas to provide a wet syngas for the water gas shift reaction. Thus, the present invention also provides a process for producing variable syngas compositions, comprising:
(a) reacting an oxidant stream with coal or petroleum coke in a gasification zone comprising at least 2 gasifiers to produce at least 2 raw syngas streams comprising carbon monoxide, hydrogen, carbon dioxide, and sulfur-containing compounds;
(b) passing a portion of at least one of the raw syngas streams from step (a) to a common water-gas shift reaction zone to produce at least one shifted syngas stream (i) having a molar ratio of hydrogen to carbon monoxide of about 1:1 to about 20:1, and at least one unshifted syngas stream (ii), comprising a remaining portion of the raw syngas streams;
(c) generating steam in the water-gas shift reaction zone by recovery of heat from the shifted syngas stream;
(d) combining a portion of the steam from step (c) with the portion of one or more raw syngas streams before passing to the water-gas shift reaction zone;
(e) blending the shifted syngas stream (i) with a portion of the unshifted syngas stream (ii) to produce at least one blended syngas stream (iii) and at least one unblended syngas stream (iv) comprising a remaining portion of unshifted syngas stream (ii); and:
(f) passing blended gas stream (iii) to a methanol or dimethyl ether producing zone and unblended gas stream (iv) to a power producing zone."
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As you can see, the explanation of the process is rather involved; and, a diagram would make it clearer.
We don't want to extrapolate overmuch; but, keep in mind that another way in which the syngas ratio can be adjusted, in addition to the water gas shift reaction, is by directing rather more of the carbon monoxide generated in the two Coal syngas generators to the "power producing zone".
Eastman, by the way, as we understand it, currently separates and sequesters Carbon Dioxide produced in it's Kingsport, TN, syngas generators and water gas shift reactors; although, as you know if you have followed our reports thus far, there are, as seen for only one example in:
West Virginia Coal Association | California July 2012 Efficient CO2 to Methanol | Research & Development; concerning: "United States Patent 8,212,088 - Efficient and Selective Chemical Recycling of Carbon Dioxide to Methanol, Dimethyl Ether and Derived Products; July 3, 2012; Inventors: George Olah and G.K. Surya Prakash, CA; Assignee: University of Southern California, Los Angeles; Abstract: An efficient and environmentally beneficial method of recycling and producing methanol fromvaried sources of carbon dioxide including flue gases of fossil fuel burning powerplants, industrial exhaust gases or the atmosphere itself. Converting carbon dioxide by chemical or electrochemical reduction secondary treatment to produce essentially methanol, dimethyl ether and derived products";some better, more productive options for the utilization of any co-produced Carbon Dioxide, which could lead to an increased production of desired products, like the specified Methanol, and other chemicals, which would include other liquid fuels among the specified "Fischer-Tropsch products", and electrical power, from a Coal conversion and power generation facility like that disclosed by our subject herein, "US Patent Application 20070129450 - Process for Producing Variable Syngas Compositions".
As we indicated in our introductory comments, we will see in some reports to follow that such potentials for the co-production of both hydrocarbon chemicals and electrical power from Coal, in a single, integrated facility have been examined and even further developed by others.
And, it all serves to further enhance and to increase the value of our already by far most abundant, most valuable fossil resource: Coal.