United States Patent: 8801919

We have, of course, presented many reports here concerning South Africa's Coal conversion industry, wherein South Africa Synthetic Oil Limited, "SASOL", has been converting Coal at multiple factories into synthetic petroleum fuels for well more than half a century.

Sasol utilizes a modern version of the nearly-ancient Fischer-Tropsch process for converting Coal into liquid hydrocarbons, a technique known generically as "indirect" Coal conversion, since Coal is first partially combusted to form a "synthesis gas", or "syngas" blend of Carbon Monoxide and Hydrogen. The syngas is then catalytically, chemically condensed into hydrocarbons.

 

And, as seen for only one example in:

South Africa 2012 Coal to Hydrocarbon Syngas | Research & Development | News; concerning: "United States Patent 8,158,029 - Method for the Production of Synthesis Gas and of Operating a Fixed Bed Dry Bottom Gasifier; 2012; Assignee: Sasol Technology Ltd., Johannesburg; Abstract: A method for the production of synthesis gas includes humidifying an oxygen-containing stream by contacting the oxygen-containing stream with a hot aqueous liquid to produce a humidified oxygen-containing stream, and feeding the humidified oxygen-containing stream into a gasifier in which a carbonaceous material is being gasified, thereby to produce synthesis gas. ... A method for the production of synthesis gas (with) the gasifier forming part of a complex for Fischer-Tropsch hydrocarbon synthesis ... . There are various gasification technologies available to gasify a carbonaceous material, such as coal, to produce synthesis gas. With suitable coal used for fixed bed dry bottom gasification technology, less oxygen and coal are required for the production of a particular effective amount of synthesis gas ... . The hydrocarbon synthesis may be Fischer-Tropsch synthesis (and, liquid) hydrocarbon product is produced in the Fischer-Tropsch hydrocarbon synthesis stage ... . The ... invention, as illustrated, results in improved efficiency in the manufacturing of synthesis gas (from) coal";

Sasol continue to make improvements in their Coal-conversion processes. And, which processes, as seen in our report of:

South Africa Co-produces Power and Hydrocarbons from Coal | Research & Development | News; concerning: "United States Patent 8,247,462 - Co-production of Power and Hydrocarbons; 2012; Assignee: Sasol Technology Limited, South Africa; Abstract: A process for co-producing power and hydrocarbons includes in a wet gasification stage, gasifying coal to produce a combustion gas at elevated pressure comprising at least H2 and CO; enriching a first portion of the combustion gas with H2 to produce an H2-enriched gas; and generating power from a second portion of the combustion gas";

can allow for the synergistic co-production of a certain amount of electrical power, along with liquid hydrocarbon fuels, in one integrated process and facility, from Coal. 

Keep in mind that various departments of our United States Government have studied South Africa's Coal conversion industry, and, as seen in:

US EPA Recommends Coal Liquefaction as a Clean Alternative | Research & Development | News; concerning: "Clean Alternative Fuels: Fischer-Tropsch; United States Environmental Protection Agency; Transportation and Air Quality Transportation and Regional Programs Division; EPA420-F-00-036; March 2002; A Success Story (!) For the past 50 years, Fischer-Tropsch fuels have powered all of South Africa’s vehicles, from buses to trucks to taxicabs.The fuel is primarily supplied by Sasol, a world leader in Fischer-Tropsch technologies.Sasol’s South African facility produces more than 150,000 barrels of high quality fuel from domestic low-grade coal daily";

even the United States Environmental Protection Agency has confirmed that hydrocarbon fuels can be made efficiently and cleanly from Coal.

Sasol produces all forms of liquid hydrocarbon fuels from Coal, including, as reported separately in:

Sasol's synthetic jet fuel to gain worldwide approval by August; concerning: "'Sasol's synthetic jet fuel to gain worldwide approval by August'; The world will soon be flying on coal. This is because groundbreaking work done by petrochemical giant Sasol on the production of synthetic jet fuel from coal, is expected to gain worldwide approval from aviation authorities for the fuel by August, Engineering News can today exclusively report. This paves the way for Sasol to supply aviation fuel produced fully from coal";

a fully synthetic jet fuel, that, as seen in:

Sasol 100% CTL Synthetic Jet Fuel Approved for Use Internationally in Commercial Aviation; wherein it's reported, that: Sasol’s synthetic jet fuel, produced by its proprietary Coal to Liquids (CTL) process, has received approval for full, unblended use in international commercial aviation. Sasol’s fully synthetic jet fuel (FSJF) is the first such fuel to be approved. For the past nine years, Sasol has supplied a semi-synthetic jet fuel - a mixture of CTL components with petroleum-derived kerosene - to international airlines operating from OR Tambo International Airport in Johannesburg. Based on the success of the alternative fuel blend and following a several-year period of testing and evaluation, international aviation fuel authorities including the UK Ministry of Defence (UK MoD), governing the Defence Standard DEFSTAN 91-91, approved Sasol’s fully synthetic jet fuel as Jet A-1 fuel for commercial use in all types of turbine aircraft";

did receive international approval for use in "all types" of jet planes. As noted, international airliners have for years been fueled with an aviation fuel blend containing, in part, Coal-derived liquid hydrocarbons at South Africa's Johannesburg International Airport. And, as seen in our report of:

B-52 Bombers Fly on Coal | Research & Development | News; concerning:  "8/8/2007 - EDWARDS AIR FORCE BASE, Calif. (AFPN) -- Secretary of the Air Force Michael W. Wynne announced the completion of the Air Force's certification of the Fischer-Tropsch fuel blend in the B-52H Stratofortress ... . The signing ceremony certified that the blended FT and JP-8 fuel is safe for operational use in all B-52H aircraft and marked the formal conclusion of testing";

our United States Air Force has, as well, tested such and similar Coal-derived hydrocarbon and standard jet fuel blends and found them to be perfectly "operational" in their own strategic jet aircraft.

As noted above, Sasol has developed a 100% Coal-derived jet fuel that has received approval for use from international aviation authorities. And, what we presume to be their process for making that 100% Coal jet fuel was disclosed in our report of:

South Africa seeks US Coal-to-Jet Fuel Patent | Research & Development | News; concerning: "United States Patent Application 20100264061A1 - Synthetic Aviation Fuel; 2010; Inventor: Carl Louis Viljoen, et. al., South Africa; Assignee: Sasol Technology Ltd., Johannesburg; Abstract: The invention relates to a Fischer-Tropsch derived aviation fuel, which fuel is used either as a fuel on its own or as a component in an aviation fuel blend ... . This invention relates to an improved Fischer-Tropsch derived aviation fuel ... . Distillate fuel derived from the Fischer-Tropsch (FT) process is highly paraffinic and has excellent burning properties and very low sulfur. This makes Fischer-Tropsch products ideally suited for fuel use where environmental concerns are important. Clean distillates with low emission characteristics that contain low sulfur, nitrogen or aromatics such as distillates from the Fischer-Tropsch process will in the future be in great demand as aviation fuel or in blending aviation fuel. The FT process is used industrially to convert synthesis gas, which may be derived from coal ... into hydrocarbons ranging from methane to species with molecular masses above 1400".

And, herein we learn that technical experts in the employ of our United States Government, just a little more than one month ago, confirmed the validity of the process disclosed in the above "United States Patent Application 20100264061A1 - Synthetic Aviation Fuel", whereby such acceptable jet fuel can be manufactured entirely from Coal.  

As seen in excerpts from the initial link in this dispatch to:

"United States Patent 8,801,919 - Fully Synthetic Jet Fuel

Patent US8801919 - Fully synthetic jet fuel - Google Patents

Fully synthetic jet fuel - Sasol Technology (Pty) Ltd

August 12, 2014

Inventors: Carl Louis Viljoen and Miriam Ajam, South Africa

Assignee: Sasol Technology Ltd, Johannesburg

Abstract: The invention provides a fully synthetic aviation fuel or aviation fuel component having: a total naphthenic content (as specified). The invention further provides for the preparation of a fully synthetic coal-derived aviation fuel or aviation fuel component ... . The invention extends to a method of producing a coal-derived, fully synthetic aviation fuel or aviation fuel component from coal gasifier tar and an LTLF derived fraction.

Claims: A fully synthetic aviation fuel or aviation fuel component (as specified).

The fully synthetic aviation fuel or aviation fuel component ... derived from a single non-petroleum source and comprising a blend of at least two blend components, wherein at least one of the blend components is produced from a low temperature Fischer-Tropsch process

A method of preparing the fully synthetic aviation fuel or aviation fuel component ... comprising: blending at least: a first low temperature Fischer-Tropsch-derived blend component (as described) and a second tar-derived blend component (as described) whereby a fully synthetic aviation fuel or aviation fuel component comprising from 20 volume % to 60 volume % of the first low temperature Fischer-Tropsch-derived blend component is obtained (and) wherein the second tar-derived blend component is generated through a recovery of a tar-derived kerosene fraction generated during gasification of a coal feedstock for syngas production.

A method of preparing the fully synthetic aviation fuel or aviation fuel component ... comprising: gasifying a coal under medium to low temperature conditions in a fixed bed gasifier such that a tar fraction and syngas are recovered; generating a low temperature Fischer-Tropsch syncrude from the syngas in a low temperature Fischer-Tropsch reactor; subjecting the tar fraction to hydroprocessing under hydroprocessing conditions to obtain a tar-derived kerosene fraction (as described); subjecting the low temperature Fischer-Tropsch syncrude to hydroprocessing under hydroprocessing conditions to provide a low temperature Fischer-Tropsch-derived kerosene (as described) and blending the tar-derived kerosene fraction and the low temperature Fischer-Tropsch-derived kerosene to obtain a fully synthetic aviation fuel ... .

The method ...  wherein the tar-derived kerosene fraction is produced by a medium temperature coal gasification process operating at a temperature of from 700 to 900 C, wherein both naphthenics and aromatic hydrocarbons are produced during the medium temperature coal gasification process.

Background and Field: The present invention relates generally to aviation fuel and a blending stock for aviation fuel. More particularly, it relates to an aviation fuel or fuel component which is derived from a non-petroleum feedstock. 

Distillate fuels produced from non-petroleum sources and derived largely from the Fischer Tropsch (FT) process are typically highly paraffinic and have excellent burning properties and very low sulphur content. This makes them highly suitable as a fuel source where environmental concerns are important; and in circumstances where the security of supply and availability of petroleum supplies may cause concern. 

However, although many physical properties for conventional distillate fuels can be matched and even outperformed, the fuels derived from FT processes and the like can not provide conventional jet fuel "drop-in compatibility" (i.e. be amenable to direct substitution within the conventional petroleum-derived jet fuel infrastructure), as they lack some of the major hydrocarbon constituents of typical petroleum-derived kerosene fuel. For example, due to their low aromatic content, FT jet fuels tend not to comply with certain industry jet fuel specified characteristics such as minimum density, seal swell propensity and lubricity.

Summary: Accordingly, there remains a strong need for a fully-synthetic (i.e. non-petroleum sourced) aviation fuel and an economical means of producing it. 

The fully synthetic aviation fuel or fuel component is typically produced from a single non-petroleum source and comprises at least two blend components, where at least one component is produced from an LTFT process.

The single source may be coal. 

According to (one) aspect of the invention, there is provided a fully synthetic coal-derived aviation fuel or aviation fuel component (as specified) including a first LTFT(Low Temperature Fischer-Tropsch)-derived blend component (as specified) and a second tar-derived blend component (as specified). 

The second tar-derived blend component is typically generated through the deliberate recovery of a tar fraction generated during gasification of a coal feedstock for syngas production.

According to (another) aspect of the invention, there is provided a method of producing a coal-sourced, fully synthetic aviation fuel or aviation fuel component; including the steps of: gasifying the coal under medium temperature conditions in a fixed bed gasifier such that a tar fraction can be recovered during the coal gasification step; and syngas for an LTFT reactor is produced; recovering from (that) reactor an LTFT syncrude; subjecting the tar fraction to hydroprocessing under hydroprocessing conditions to provide a tar-derived kerosene fraction ... and blending the resultant tar-derived kerosene fraction and LTFT-derived kerosene fraction to obtain a fully synthetic aviation fuel or aviation fuel component. 

The tar-derived kerosene fraction may be produced by a medium temperature coal gasification process (i.e. between 700 and 900 C), for example by a Fixed Bed Dry Bottom (FBDB) (trade name) or fluidised bed coal gasification process. By employing a medium temperature process, a tar-derived kerosene component that contains both naphthenics and aromatics may be produced during the coal gasification step. 

According to the present invention, it has been found that it is possible to achieve a fully synthetic aviation fuel or fuel component that meets specific current conventional jet fuel requirements, (specifically density and aromatic content), through the suitable processing of a single synthetic fuel source. 

This fuel can be produced using two parallel feedstock streams - one is generated via a conventional LTFT synthesis process; and the other is generated through the deliberate recovery of a tar fraction generated during medium temperature gasification of the coal feedstock for syngas production.

(The) Low Temperature Fischer-Tropsch (LTFT) process ...  is a well known process in which carbon monoxide and hydrogen are reacted over an iron, cobalt, nickel or ruthenium containing catalyst to produce a mixture of straight and branched chain hydrocarbon products ranging from methane to waxes and smaller amounts of oxygenates. The LTFT process is therefore used industrially to convert synthesis gas, which may be derived from coal ... into hydrocarbons ranging from methane to species with molecular masses above 1400".

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We presume among readers some familiarity with the "Fischer-Tropsch" technology, wherein Coal is first gasified, as indicated in the introductory citations, to form a blend of, primarily, Carbon Monoxide and Hydrogen, and, which "syngas" is passed over any of a number of known catalysts and is thereby chemically condensed into a range of hydrocarbons of greater and lesser molecular weights, with the type of catalyst used determining to a large degree the type of hydrocarbons synthesized, as per our introductory comments.

For more information concerning the "F-T" technology, we suggest a review of the supporting information and links in our prior report of:

USDOE Pays Kentucky to Improve Fischer-Tropsch Coal Conversion | Research & Development | News; which centers on: "United States Patent Application 20110294906 - Incorporation of Catalytic Dehydrogenation into Fischer-Tropsch Synthesis to Lower Carbon Dioxide Emissions; 2011; Inventor: Gerald P. Huffman; (Presumed Assignee of Rights: University of Kentucky)".

The full Disclosure of our subject, "United States Patent 8,801,919 - Fully Synthetic Jet Fuel", is rather immensely complex, and concerns to a large degree the specifics of fuel formulation. We have edited our excerpts in the extreme to present what we see as the key facts concerning the utility of Coal in processes which synthesize what is, according to the presentation and other references, a jet fuel that is superior in many respects to the same type of fuel made conventionally from natural petroleum.

And, the potentials for manufacturing superior aviation liquid fuels from Coal is far from unknown; we have documented those potentials, and the fact that those potentials are widely known, previously a number of times. See, for one example, our prior report of:

Penn State Makes Jet Fuel from Coal for USDOE | Research & Development | News; concerning: "Advanced Thermally Stable Jet Fuels; Author: H.H. Schobert; 1999;OSTI ID: 775227; Report Number: DE--FG22-92PC92104-08; DOE Contract: FG22-92PC92104; Research Organization: Federal Energy Technology Center, Morgantown, WV; (and) Federal Energy Technology Center, Pittsburgh, PA; Sponsoring Organization: US Department of Energy;Abstract: The Pennsylvania State University program in advanced thermally stable coal-based jet fuels".

In any case, the takeaway might be this: No matter what type of liquid hydrocarbon fuel we might require, for whatever application, and especially "where environmental concerns are important; and in circumstances where the security of supply and availability of petroleum supplies may cause concern", we can make them all from, as officially certified to be true, as herein, by our United States Government, "a single non-petroleum source ... coal".


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