EPAoverreach-2014b

Exxon Co-Gasifies Coal and Carbon-Recycling Biomass

United States Patent Application: 0100083575

Buried deep in the "Background" section of the United States Patent Application we enclose herein, for a process developed by that lovable oily giant, ExxonMobil, is a statement which reveals the true intent and purpose of the invention, as follows:

"One established route to the production of hydrocarbon liquids is the gasification of carbonaceous materials followed by the conversion of the produced synthesis gas to form liquids by processes such as Fischer-Tropsch and its variants.

 

 

In this way, solid fuels such as coal ...may be converted to liquids.

Gasification can proceed from just about any organic material, including biomass, paper, plastic and rubber waste (and) may be one of the best ways to produce clean liquid fuels ... from coal.

Biomass gasification is expected to play a significant role in a renewable energy economy, because biomass production removes CO2 from the atmosphere and the net effect of processing the biomass has a net lower CO2 generation as compared to fossil fuels. (And) gasification runs on a wider variety of input materials, can be used to produce a wider variety of output fuels, and is an extremely efficient method of extracting energy from biomass. Biomass gasification is therefore one of the most technically and economically viable energy possibilities for a carbon emission constrained economy."

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We'll repeat some of that in our more extended excerpts; but, Exxon is quite clearly making some points herein, which we have earlier documented and illustrated, such as:

Coal, through long-known gasification technologies, can be efficiently converted into the raw materials from which we can catalytically condense liquid hydrocarbon fuels and chemicals, i.e., anything we now derive from increasingly-scarce natural petroleum.

Moreover, based on their chemical similarities, remembering that Coal is just fossilized Biomass, we can so efficiently convert Coal and all sorts of botanically-derived, and other, organic materials, which can either be wastes from other processes or purpose-grown, together, in the same facility, into, as ExxonMobil specifies, "hydrocarbon liquids".

Comment, with a few additional links, follows more complete excerpts from:

"US Patent Application 20100083575 - Co-gasification Process for Hydrocarbon Solids and Biomass

Date: April, 2010

Inventors: Ramesh Varadaraj, et. al., NJ

Assignee: ExxonMobil Research and Engineering Company, NJ

Abstract: A process for the co-gasification of carbonaceous solids (coal) and biomass in which the biomass material is pyrolyzed to provide a biomass pyrolysis oil and biomass char or coke which are then mixed with the carbonaceous solid to form a slurry. This slurry is then heated if necessary to achieve a viscosity which can be processed conveniently in the gasifier. The heat required for pyrolyzing the biomass can conveniently be obtained from the heat exchanger used to cool the hot synthesis gas product emerging from the gasifier.

Claims: A process for forming a slurry feed for the gasification to synthesis gas of solid carbonaceous particles and solid biomass, which comprises pyrolyzing the biomass to form biomass pyrolysis oil and biomass char; and mixing the biomass pyrolysis oil and biomass char with the solid carbonaceous particles to form the slurry feed. 

The process ... wherein the solid carbonaceous particles comprise coal.

The process ... wherein in the solid carbonaceous particles are comprised of a coke derived from coal ... .

The process ... wherein the biomass 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.

(Any Carbon-recycling garbage, really, can be utilized; but, we call your attention to the specific mention of "algae", concerning which we submit, further on, specific comment and an additional reference link.)

A process ... wherein steam is co-fed into the gasifier reactor with the ... slurry.

(The "steam" is added to provide supplemental Hydrogen for the conversion of the Carbon in the basic feed into hydrocarbon synthesis gas. However, since the Biomass has some of it's own Hydrogen, built into the carbohydrates, etc., of which it is composed, the need for such Hydrogen-supplementing Steam, with it's attendant costs, would, we are compelled to believe, be significantly reduced.)

In a specific embodiment, the present invention comprehends a process for the co-gasification of solid carbonaceous particles (such as coal) and biomass which comprises the steps of: a) pyrolyzing a biomass to provide a biomass pyrolysis oil and biomass char; b) mixing the biomass pyrolysis oil, biomass char and solid carbonaceous particles to form a complex plastic slurry of pumpable viscosity, ... ; c) pumping the slurry into the mixing zone of a gasifier where it is mixed with an oxygen containing gas; d) passing the mixture of the slurry ... through a feed injector into a gasifier reactor; and e) gasifying the mixture. 

In a preferred embodiment, the heat required for pyrolyzing the biomass can conveniently be obtained from the heat exchanger used to cool the hot synthesis gas product emerging from the gasifier.

(In other words, heat energy generated by one exothermic function of the total system can be recycled back into the system, for use in a function which requires the addition of heat.)

Background and Field: The use of liquid hydrocarbon fuels on an enormous scale for transportation has led to the depletion of readily accessible petroleum reserves in politically stable regions and this, in turn, has focused attention, economically, technically and politically on the development of alternative sources of liquid fuels. 

One established route to the production of hydrocarbon liquids is the gasification of carbonaceous materials followed by the conversion of the produced synthesis gas to form liquids by processes such as Fischer-Tropsch and its variants. In this way, solid fuels such as coal and coke may be converted to liquids.

Coal gasification is well-established, being used in many electric power plants. Gasification can proceed from just about any organic material, including biomass, paper, plastic and rubber waste. Most importantly, in a time of unpredictable variations in the prices of electricity and fuels, gasification systems can provide a capability to operate on low-cost, widely-available coal reserves. Gasification may be one of the best ways to produce clean liquid fuels and chemical intermediates from coal as well as clean-burning hydrogen which also can be used to fuel power-generating turbines or used in the manufacture of a wide range of commercial products. 

Four basic types of gasifiers are currently available for commercial use: counter-current bed, co-current bed, fluidized bed and entrained flow. In the counter-current fixed bed ("up draft") gasifier the gasification agent (steam, oxygen and/or air) flows in counter-current configuration through a descending bed of the carbon-containing fuel with the ash removed dry or as a slag. The co-current bed gasifier is similar to the counter-current type, but the gasification agent gas flows downwards in the same direction as the fuel. In the fluidized bed reactor, the fuel is fluidized in the gasification agent. In the entrained flow gasifier a dry pulverized solid, an atomized liquid fuel or a fuel slurry is gasified with oxygen or air in co-current flow and the gasification reactions take place in a dense cloud of very fine particles. Most coals are suitable for this type of gasifier because of the high operating temperatures and because the good contact achieved between the coal particles and the gasifying agent. Entrained flow gasifiers have been demonstrated as highly effective units for the gasification of coal and other carbonaceous fuels such as coke (coal derived) ... .

Summary: We have now developed a process for the co-gasification of carbonaceous solids (such as coal and coke) and biomass which enables the biomass to be fed into the gasifier using existing types of feed transfer and feed injection equipment ... .

According to the present invention, the biomass material is pyrolyzed to provide a biomass pyrolysis oil and biomass char which are then mixed with the hydrocarbon solid to form a slurry.

In a specific embodiment, the present invention comprehends a process for the co-gasification of solid carbonaceous particles (such as coal and coke) and biomass which comprises the steps of: a) pyrolyzing a biomass to provide a biomass pyrolysis oil and biomass char; b) mixing the biomass pyrolysis oil, biomass char and solid carbonaceous particles to form a complex plastic slurry of pumpable viscosity ...; c) pumping the slurry into the mixing zone of a gasifier where it is mixed with an oxygen containing gas; d) passing the mixture ...  through a feed injector into a gasifier reactor; and e) gasifying the mixture. 

In a preferred embodiment, the heat required for pyrolyzing the biomass can conveniently be obtained from the heat exchanger used to cool the hot synthesis gas product emerging from the gasifier.

Gasification may be carried out in the conventional manner with steam co-feed according to the feed composition to generate the desired synthesis gas."

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Once again: Such "desired synthesis gas", so economically derived from a blend of our abundant Coal and Carbon-recycling waste, or purpose-grown, organic materials, is intended for use in a process that will "form liquids ... such as Fischer-Tropsch and its variants".

And, we must mention that ExxonMobil specifies not just Coal, but, "coke derived from coal".

We submit that, if "coal-derived" Coke can also be used, we then have opportunity to first process our Coal in Coke Ovens, before sending the Coke to ExxonMobil's process; and, as seen, for just one example, in our earlier report:

Coke Oven Gas to Synfuel | Research & Development; wherein is disclosed information concerning "a methanol project based on coke oven gas", that:

Coke Oven gas can itself be collected, as it is being driven off the raw Coal, and then be catalytically condensed directly into a variety of liquid fuels, such as, as in the Chinese project described in the above citation, the quite valuable Methanol; which, among many other uses, can, via, for one instance, ExxonMobil's own "MTG"(r) process, be directly converted into Gasoline.

The residual Coke could then be passed on to ExxonMobil's process herein, of United States Patent Application 20100083575, for further conversion, into their "desired" liquid hydrocarbon "synthesis gas".

We further note that, as above, "algae" is specified to be one of the preferred substances, from a wide collection of named "biological matter", which can, herein, be so converted, along with Coal, into that "desired" liquid hydrocarbon "synthesis gas".

And, we remind you of: Honeywell Recycles CO2 with Algae | Research & Development; wherein we reported the article: "Honeywell's UOP Awarded Funding for Carbon Dioxide Reuse Through Algae Biofuel Production; 2010; UOP, a Honeywell company, announced today ... a project to demonstrate technology to capture carbon dioxide and produce algae for use in biofuel and energy production. Algal oil can ... be extracted from the algae for conversion to biofuels, and the algae residual can be converted to pyrolysis oil."

We further suggest you consider, that, such "algae residual" - - remaining, according to Honeywell, after the liquid algal "oil", for use in "biofuels", had been extracted, from Algae nourished by industrial off-gas Carbon Dioxide - - can then be converted into "pyrolysis oil", again according to Honeywell, which is exactly what ExxonMobil herein specifies, as in: "pyrolyzing a biomass to provide a biomass pyrolysis oil" to provide the liquid in which "carbonaceous particles", i.e., Coal particles, are to be mixed "to form a complex plastic slurry of pumpable viscosity (and which is then pumped) into the ... gasifier where it is" converted into hydrocarbon "synthesis gas".

We could, in sum, grow Algae in bio-reactors attached to our Coal-fired power plants; nourish that Algae with CO2 and waste heat generated by those power plants, extract "oil", i.e., bio-diesel, from that Algae, and, then, thermally treat the semi-solid CO2-recycling Algal wastes from that bio-diesel extraction, to form a "pyrolysis oil", and, as per ExxonMobil's process herein, suspend Coal particles - - and, particles, as ExxonMobil specfies, "of any organic" surplus or waste Carbon-recycling "material, including biomass, paper, plastic and rubber" - - in that pyrolysis oil, along with the "char" resulting from the pyrolysis of the Algae oil extraction residues, and, then, with added "steam", as in ExxonMobil's specifications, convert them all into a "synthesis gas", which, through the "Fischer-Tropsch" process, "and its variants", we can condense into "clean liquid fuels and chemical intermediates".