July 8, 2014, Coal and Carbon-Recyling Wastes to Methane

United States Patent: 8771388

The University of California, in the persons of Professor Joseph Norbeck and his immediate colleagues, has established an immense and comprehensive body of technology for converting Coal, along with an extensive array of renewable and Carbon-recycling wastes, indirectly, through an initial process of gasification, into synthetic liquid hydrocarbon transportation fuels and into synthetic natural gas Methane.

 

Representative of such technologies developed by them is that seen in our report of:

California Hydrogasifies Coal & Carbon-Recycling Wastes | Research & Development | News; concerning: "US Patent 7,500,997 - Steam Pyrolysis ... to Enhance the Hydro-Gasification of Carbonaceous Materials; 2009; Inventors: Joseph Norbeck and Collin Hackett; Assignee: The Regents of the University of California; Abstract: A process and apparatus for producing a synthesis gas for use as a gaseous fuel or as feed into a Fischer-Tropsch reactor to produce a liquid fuel in a substantially self-sustaining process. In one embodiment, a slurry of carbonaceous material in water, and hydrogen from an internal source, are fed into a hydro-gasification reactor to generate methane rich producer gases which are fed into a steam pyrolytic reformer to generate synthesis gas comprising hydrogen and carbon monoxide. A portion of the hydrogen is used as the internal hydrogen source. The remaining synthesis gas is either used as fuel to produce electricity and/or process heat or is fed into a Fischer-Tropsch reactor to produce liquid fuel".

In nearly all of the Norbeck-University of California technologies for such "Hydro-Gasification" of Coal and other organic raw materials, like that seen as well in:

California Coal, Biomass and Waste Plastic to Hydrocarbons | Research & Development | News; concerning: "US Patent 7,897,649 - Steam Methane Reformer (utilizing) Gas from Steam Hydro-Gasification; 2011; Inventors: Joseph Norbeck and Chan Seung Park; Assignee: The Regents of the University of California; Abstract: An improved, economical alternative method to supply steam and methane to a steam methane reformer (SMR) is accomplished by a combination of procedures, wherein product gas from a steam hydro-gasification reactor (SHR) is used as the feedstock for the SMR by removing impurities from the product stream from the SHR with a gas cleanup unit that operates substantially at process pressures and at a temperature above the boiling point of water at the process pressure, is located between the SHR and the SMR. Claims: A process for converting carbonaceous material to synthesis gas, comprising: heating a slurry, comprising water and carbonaceous material, with hydrogen in a steam hydrogasifier reactor, at a sufficient temperature and pressure to generate a stream of methane, carbon monoxide, and steam rich product gas; wherein the steam in the hydrogasifier is generated as the result of superheating the slurry water; removing sulfur impurities from the producer gas stream; and subjecting the resultant product gas to steam methane reforming, conditions; whereby synthesis gas comprising hydrogen and carbon monoxide is generated at a ratio of between 2:1 and 6:1. The process ... wherein the carbonaceous material comprises municipal waste, biomass, wood, coal, or a natural or synthetic polymer. The process ... in which synthesis gas generated by the steam methane reforming is fed into a Fischer-Tropsch reactor under conditions whereby a liquid fuel is produced";

the end goal of gasifying carbonaceous material is to obtain a synthesis gas blend of Carbon Monoxide and Hydrogen suitable for the "Fischer-Tropsch" production of "liquid fuels". Thus, any Methane co-produced in the initial gasification of the Coal, and other Carbon-containing materials, is slated to be separated and then "reformed" with Steam, H2O, so as to form a second, Hydrogen-rich synthesis gas which can be, in essence, blended with the Carbon Monoxide and Hydrogen blend of syngas evolved in the initial gasification, so as to form a combined syngas better-suited compositionally for such Fischer-Tropsch conversion into liquid hydrocarbon fuels.

That fact is re-emphasized in another of the University of California's Coal conversion technologies about which we reported in:

California 2012 Coal and Carbon-Recycling Waste to Syngas | Research & Development | News; concerning: "United States Patent 8,143,319 - Steam Hydro-Gasification with Increased Conversion Times; 2012; Inventors: Chan Seung Park and Joseph Norbeck; Assignee: The Regents of the University of California; Abstract: A method and apparatus for converting carbonaceous material to a stream of carbon rich gas, comprising heating a slurry feed containing the carbonaceous material in a hydrogasification process using hydrogen and steam, at a temperature and pressure sufficient to generate a methane and carbon monoxide rich stream ... . In particular embodiments, the slurry feed containing the carbonaceous material is fed, along with hydrogen, to a kiln type reactor before being fed to the fluidized bed reactor. ... Optionally, a grinder can be provided in the kiln type reactor. The process ... wherein the carbonaceous material is solid. The process ... including the step of subjecting the stream of methane and carbon monoxide rich gas to steam methane reforming under conditions whereby synthesis gas comprising hydrogen and carbon monoxide is generated. The process ... in which synthesis gas generated by the steam methane reforming is fed into a Fischer-Tropsch-type reactor under conditions whereby a liquid fuel is produced. Background and Field: The field of the invention is the synthesis of transportation fuel from carbonaceous feed stocks".

All of the above, and other related, University of California gasification technologies, even though the end goal is liquid "transportation fuel", do at least suggest the potential of producing substitute natural gas Methane, instead, as the end product to be derived "from carbonaceous feed stocks".

And, that seems the intent of the innovation we report to you herein, embodied as a United States Patent which was awarded just yesterday, in which the product gases arising from an initial gasification are treated so that, instead of steam-gasifying the co-product Methane to maximize the production of synthesis gas, the other syngas components are treated so as to maximize the production of substitute natural gas Methane.

First, to emphasize one point, we note, that, due to current availabilities of various feedstock, and the needed economies of scale, this is a process that would have to be founded on Coal as the core, primary raw material. But, as seen in an advance excerpt, specifically Claim 11 of the full Disclosure:

"The process ... wherein the carbonaceous material comprises municipal waste, biomass, wood, coal, biosolids, or a natural or synthetic polymer";

as with the other UC-Norbeck technologies, any Carbon-containing raw material, in essence, can be tossed into the gasifier with the Coal, providing obvious advantages in terms of sustainability and Carbon emission offsets and management.

That figures into other aspects of the process of our subject, as we attempt to explain via comment inserted in excerpts from the initial link in this dispatch to:

"United States Patent 8,771,388 - Method to Produce Methane Rich Fuel Gas from Carbonaceous Feedstocks Using a Steam Hydrogasification Reactor and a Water Gas Shift Reactor

Method to produce methane rich fuel gas from carbonaceous feedstocks using a steam hydrogasification reactor and a water gas s

Date: July 8, 2014

Inventors: Joseph Norbeck, et. al., California

Assignee: The Regents of the University of California, Oakland

Abstract: A method for producing high levels of methane based on a combination of steam hydrogasification and a shift reactor is provided. Hydrogen produced by the shift reactor can be recycled back into the steam hydrogasifier.

(The "shift reactor", as we've previously reported, is a vessel for conducting the water gas shift reaction:

Water-gas shift reaction - Wikipedia, the free encyclopedia; wherein Carbon Monoxide reacts with Water, H2O, to form Carbon Dioxide and the additional Hydrogen needed for Methane synthesis. As we'll touch on briefly in additional comments, options exist to either supply the additional needed Hydrogen via other routes, or, to productively utilize the by-product Carbon Dioxide. Keep in mind that Carbon-recycling wastes can be included with the Coal raw material feed; so, even with some Carbon Dioxide being co-produced in the specified "shift reactor", this could still, over all, be a Carbon-neutral process in terms of total Carbon Dioxide emissions.)

Claims: A process for converting carbonaceous material into methane-rich fuel gas, comprising: simultaneously heating in a steam hydrogasification reactor the carbonaceous material in the presence of both hydrogen and steam, at a temperature and pressure sufficient to generate a stream of methane and carbon monoxide rich product gas; subjecting the methane and carbon monoxide rich produce gas in a shift reactor to a shift reaction to thereby form a shifted methane rich produce gas, wherein steam for the shift reaction is provided by the unreacted steam from the steam hydrogasification reactor; wherein the carbon monoxide in the product reacts in the shift reactor with steam to produce hydrogen, and wherein the steam used to react with the carbon monoxide in the shift reactor is obtained only from the steam hydrogasification reactor; and separating the hydrogen from the shifted methane rich product gas, and recycling at least part of the separated hydrogen to the steam hydrogasification reactor. 

The process ... wherein the carbonaceous material is provided in slurry form. 

(Concerning the above, see our report of:

California Blends Coal with Biomass for Gasification | Research & Development | News; concerning: "United States Patent 8,118,894 - Commingled Coal and Biomass Slurries; 2012; Inventors: Joseph Norbeck, et. al., CA; Assignee: The Regents of the University of California, Oakland; Abstract: An energy efficient process for converting biomass into a higher carbon content, high energy density slurry. ... In (one) embodiment, the biomass water slurry can be mixed with a coal water slurry to further optimize the carbon content and pumpability of the biomass slurry. A process for converting biomass into a higher carbon content, high energy density slurry, comprising: providing ground coal and a pretreated biomass slurry; and forming from the ground coal and the pretreated biomass slurry a coal-biomass slurry having a viscosity (as specified) and having a solid loading of at least 40 weight percent".)

The process ... whereby methane content of the methane and carbon monoxide rich product gas is between 30-40% on a dry mole basis. 

The process ... wherein all of the separated hydrogen is recycled back into the steam hydrogasification reactor. 

The process ... wherein the heating is performed without a catalyst (and) without the injection of oxygen. 

(Note that this is intended to be an oxygen-starved process; and, proceeds with the addition of supplemental heat, although that doesn't seem well-exposed in the full Disclosure. To conserve fuel, such supplemental heat could be supplied as it is in a conceptually-similar process, like that seen in our report of:

USDOE Hydrogasifies Coal with Solar Power | Research & Development | News; concerning: "United States Patent 4,415,339 - Solar Coal Gasification Reactor; 1983; Assignee: The USA, as represented by the Department of Energy; Abstract: Coal (or other carbonaceous matter, such as biomass) is converted into a duct gas that is substantially free from hydrocarbons. The coal is fed into a solar reactor, and solar energy is directed into the reactor onto coal char, creating a gasification front and a pyrolysis front. A gasification zone is produced well above the coal level within the reactor. A pyrolysis zone is produced immediately above the coal level. Steam, injected into the reactor adjacent to the gasification zone, reacts with char to generate product gases. Solar energy supplies the energy for the endothermic steam-char reaction. The hot product gases  flow from the gasification zone to the pyrolysis zone to generate hot char. Gases are withdrawn from the pyrolysis zone and reinjected into the region of the reactor adjacent the gasification zone. This eliminates hydrocarbons in the gas by steam reformation on the hot char. The product gas is withdrawn from a region of the reactor between the gasification zone and the pyrolysis zone. The product gas will be free of tar and other hydrocarbons, and thus be suitable for use in many processes. ... The present invention relates in general to hydrocarbon gasification, and more particularly to a hydrocarbon gasification system utilizing solar energy. The United States has a vast energy resource in the form of coal. The energy can be released from the coal through conventional power plant technology, wherein the coal is burned to produce steam and the steam is in turn used to produce electricity. It is also possible to produce a synthetic gas from coal that can be used in place of natural gas. It is, however, important to note that projected energy shortages for the United States over the near term appear to be for liquid fuels, particularly liquid fuels for powering automobiles and other forms of transportation. A system that would utilize hydrocarbons such as the vast coal deposits for the economical production of liquid fuels would be an important contribution to solutions to energy problems facing the United States. Preliminary research has demonstrated the potential for utilizing solar energy to gasify coal and/or other carbonaceous matter such as ... biomass. Conventional gasifiers burn part of the coal to provide the heat required to drive the gasification reactions. A solar gasifier uses focused sunlight to provide this heat, which incorporates a renewable energy source in the gasification process. ... Since solar energy is used rather than burning part of the coal to provide energy, less coal is required which conserves that resource".

Although such a Solar option might not be practicable in cloudy old Coal Country, there are other possibilities. And, would anyone in West Virginia really mind if we were loading more WV Coal into trains on tracks headed south to Florida? Maybe a few of us with the chills could go along to ride shotgun.)

The process ... further comprising a step of removing sulfurous contaminants from the product gas before the step of subjecting the methane and carbon monoxide rich product gas in a shift reactor to a shift reaction.

(Concerning the above "sulfurous contaminants", if we are, as in our immediately-previous comment, shipping our Coal to Florida for operation of this process, remember that they do, in Florida, as seen in our  report of:

Florida Hydrogen and Sulfur from H2S | Research & Development | News; concerning: "United States Patent 6,572,829 - Photocatalytic Process for Decomposing Hydrogen Sulfide; 2003; Inventors: Clovis Linkhouse and Nazim Muradov, FL; Assignee: University of Central Florida, Orlando; Abstract: System for separating hydrogen and sulfur from hydrogen sulfide (H2S) gas produced from oil and gas waste streams. Hydrogen sulfide (H2S) gas is passed into a scrubber and filtration unit where it encounters polysufide solution. Elemental sulfur is freed and filtered through a porous media and continues to a stripper where excess H2S is removed. The excess H2S returns to the scrubber and filtration unit, while the sulfide solution passes into a photoreactor. The sulfide solution inside the photoreactor is oxidatively converted to elemental sulfur and complexed with excess sulfide ion to make polysulfide ion, while water is reduced to hydrogen. Hydrogen percolates out of the photoreactor, while the polysulfide solution is fed back to the scrubber where the system starts over";

have even more solar-powered technology in hand which would allow conversion of those "sulfurous contaminants" into commercially-valuable Sulfur and even more Hydrogen for the Coal/Biomass hydrogasification process - which would at least reduce the need for the CO2-generating "shift reactor", wherein Hydrogen is produced via reaction between excess Carbon Monoxide and H2O.)

The process ... further comprising a step of controlling the composition of the product gas from the steam hydrogasification reaction by varying the steam to carbon and the H2 to carbon ratio of the feed. 

The process ... wherein the carbonaceous material comprises municipal waste, biomass, wood, coal, biosolids, or a natural or synthetic polymer. 

A process for converting a slurry of carbonaceous material in water into methane-rich fuel gas, comprising: simultaneously heating in a hydrogasification reactor the carbonaceous material in the presence of both hydrogen and steam, at a temperature and pressure sufficient to generate a stream of methane and carbon monoxide rich product gas, wherein all of the steam required for the hydrogasification is formed from the water in the slurry, and feeding the product gas to a shift reactor, wherein the carbon monoxide of the product gas reacts with unreacted steam from the steam hydrogasification reactor at a temperature of between 200 to 450 C to produce hydrogen, and wherein the methane is insert(ed) at the temperature in the shift reactor to thereby form a methane rich shifted product gas. 

A process for converting a slurry of carbonaceous material in water into methane-rich fuel gas, comprising: simultaneously heating in a steam hydrogasification reactor the carbonaceous material in the presence of both hydrogen and steam, at a temperature and pressure sufficient to generate a stream of methane and carbon monoxide rich product gas that further contains unreacted steam: wherein all of the steam required for the hydrogasification is formed from the water in the slurry; removing sulfurous contaminants from the product gas in the presence of the unreacted steam; subjecting the carbon monoxide in the produce gas in a shift reactor to a shift reaction at a temperature at which methane is inert to thereby form a shifted methane rich produce gas, wherein steam for the shift for shift reaction is provided by the unreacted steam; and separating hydrogen from the shifted methane rich product gas, and recycling at least part of the separated hydrogen to the steam hydrogasification reactor.

Summary: This invention provides a process for providing a high concentration methane, between 0.2 to 40% on a mole basis, where conventional problems associated with hydrogen supply and low carbon conversions are overcome. 

In one embodiment of the invention, a process for converting carbonaceous material into methane-rich fuel gas is provided involving simultaneously heating in a hydrogasification reactor the carbonaceous material in the presence of both hydrogen and steam, at a temperature and pressure sufficient to generate a stream of methane and carbon monoxide rich product gas, 

In more particular embodiments, the carbonaceous material is provided in slurry form. 

In another embodiment, the process further includes feeding the product gas to a shift reactor, wherein the CO rich gas product reacts with steam to produce H2. In a more particular embodiment, the hydrogen produced by the shift reactor is recycled back into the hydrogasification reactor. 

In yet other embodiments, catalysts, hot solid, or injection of oxygen into the hydrogasifier is not required. 

The composition of the product gas from steam hydrogasification reaction can be controlled by varying the steam to carbon and the H2 to carbon ratio of the feed. The carbonaceous material used in the invention can be municipal waste, biomass, wood, coal, biosolids, or a natural or synthetic polymer". 

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There are a number of things going on here that deserve much fuller exposition than space constraints will allow us to provide.

First of all, we feel obliged to again note, that, as seen in:

Texaco Makes Methane from Coal & "Stuff" | Research & Development | News; concerning, in part:

"United States Patent 3,888,043 - Production of Methane; 1975; Inventor: Edward Child, et. al., California; 
Assignee: Texaco Incorporated, New York; Abstract: Continuous process for the production of a gaseous stream comprising at least 90 mole % of methane (dry basis) from a sulfur containing hydrocarbonaceous fuel without polluting the environment ... . The product gas ... may be used as a substitute for natural gas or as a feedstock for organic chemical synthesis.The process ... wherein said hydrocarbonaceous fuel is a pump-able slurry of solid carbonaceous fuels selected from the group consisting of coal, particulate carbon, ... concentrated sewer sludge in a vaporizable carrier such as water";

technologies in many ways like our subject have been around for some time now. And, as seen in:

USDOE and Arizona Coal to Methane + Electricity | Research & Development | News; "United States Patent 8,236,072 - System and Method for Producing Substitute Natural Gas from Coal; 2012; Assignee: Arizona Public Service Company, Phoenix; Abstract: The present invention provides a system and method for producing substitute natural gas and electricity, while mitigating production of any greenhouse gasses. The system includes a hydrogasification reactor, to form a gas stream including natural gas and a char stream, and an oxygen burner to combust the char material to form carbon oxides. The system also includes an algae farm to convert the carbon oxides to hydrocarbon material and oxygen";

there are variations which allow the co-generation of electricity along with the substitute natural gas Methane, and, which allow for "algae farms" to capture and consume Carbon Dioxide originating from any part of the process.

Such CO2-capturing "algae", we suggest, could then comprise a part of the "biomass" with which the Coal is to be hydro-gasified in the process of our subject, "United States Patent 8,771,388 - Method to Produce Methane Rich Fuel Gas from Carbonaceous Feedstocks Using a Steam Hydrogasification Reactor and a Water Gas Shift Reactor". And, we remind you that, as seen for only one recent example in:

Ohio University Photo-Bio Reactor for CO2 Utilization | Research & Development | News; concerning: "United States Patent 8,470,584 - Apparatus and Method for Growing Biological Organisms for Fuel and Other Purposes; 2013; Inventors: David Bayless, et. al.; Assignee: Ohio University, Athens, OH";

"bio-reactors", for the growth of such CO2-consuming Algae, are becoming ever more sophisticated and effective.

On the other hand, even though Algae would grow well in Florida, where we speculated a Methane synthesis operation like that disclosed herein would be ideally situated, other options for using solar energy, like that seen in our report of:

USDOE and California Solar Hydrogen for CO2-to-Fuel Conversion | Research & Development | News; concerning: "United States Patent Application 20130092549 - Proton Exchange Membrane Electrolysis Using Water Vapor as a Feedstock; 2013; Assignee: California Institute of Technology, Pasadena; Abstract: A light-driven electrolytic cell that uses water vapor as the feedstock and that has no wires or connections whatsoever to an external electrical power source of any kind. In one embodiment, the electrolytic cell uses a proton exchange membrane (PEM) with an IrRuOx water oxidation catalyst and a Pt black water reduction catalyst to consume water vapor and generate molecular oxygen and a chemical fuel, molecular hydrogen. The operation of the electrolytic cell using water vapor supplied by a humidified carrier gas has been demonstrated under varying conditions of the gas flow rate, the relative humidity, and the presence or absence of oxygen. The performance of the system with water vapor was also compared to the performance when the device was immersed in liquid water. Government Interests: This invention was made with government support under DE-SC0004993/T-105066 awarded by the Department of Energy. The government has certain rights in the invention";

exist, which technologies could generate the additional Hydrogen needed by the Methane-producing "Hydrogasification Reactor" segment of our subject, and, thus, minimize the need for the "Water Gas Shift Reactor" which, although it does generate the needed Hydrogen from H2O and Carbon Monoxide extracted from the gasification product stream, also co-produces the by-product Carbon Dioxide.

All of that might be confusing, but, the sum of it all is this:

As officially confirmed just yesterday by our United States Government, Coal, in combination with renewable and carbon-recycling products and wastes, i.e., "municipal waste, biomass, wood, ... biosolids, or a natural or synthetic polymer", can be efficiently and directly converted into substitute natural gas Methane.

And, the process can be conducted in ways, especially with those renewable feedstocks, and in concert with the auxiliary technology discussed, that it can be, in essence, Carbon-neutral, or, conceivably, what might even be thought of as Carbon-negative.

Further, in addition to producing substitute natural gas Methane for use in it's conventional applications, the process of our subject and the Methane it produces from Coal and carbon-recycling Biomass and wastes, in concert with other University of California technologies, such as that disclosed in our above-cited report concerning:

"US Patent 7,897,649 - Steam Methane Reformer (utilizing) Gas from Steam Hydro-Gasification; 2011; Inventors: Joseph Norbeck and Chan Seung Park; Assignee: The Regents of the University of California; Abstract: An improved, economical alternative method to supply steam and methane to a steam methane reformer (SMR) is accomplished by a combination of procedures, wherein product gas from a steam hydro-gasification reactor (SHR) is used as the feedstock for the SMR by removing impurities from the product stream from the SHR with a gas cleanup unit that operates substantially at process pressures and at a temperature above the boiling point of water at the process pressure, is located between the SHR and the SMR. Claims: A process for converting carbonaceous material to synthesis gas, comprising: heating a slurry, comprising water and carbonaceous material, with hydrogen in a steam hydrogasifier reactor, at a sufficient temperature and pressure to generate a stream of methane, carbon monoxide, and steam rich product gas; wherein the steam in the hydrogasifier is generated as the result of superheating the slurry water; removing sulfur impurities from the producer gas stream; and subjecting the resultant product gas to steam methane reforming, conditions; whereby synthesis gas comprising hydrogen and carbon monoxide is generated at a ratio of between 2:1 and 6:1. The process ... wherein the carbonaceous material comprises municipal waste, biomass, wood, coal, or a natural or synthetic polymer. The process ... in which synthesis gas generated by the steam methane reforming is fed into a Fischer-Tropsch reactor under conditions whereby a liquid fuel is produced";

could, in fact, provide for our domestic supply of liquid hydrocarbon fuels, as well. And, in final sum, as our supplies of shale natural gas dwindle much quicker than it's proponents would prefer to have you know, and, as OPEC continues to turn the screws, we do have one, single, four-letter and offensive - to them - word answer to all of that:

Coal.