United States Patent: 4415339

 

As now available via: NASA Hydrogasifies Coal with Solar Power | Research & Development | News; we recently made report of: United States Patent: 4290779 - "Solar Heated Fluidized Bed Gasification System; 1981; Assignee: NASA", wherein was revealed a technology that provides for a "solar-powered fluidized bed gasification system for gasifying carbonaceous material", i.e., Coal, with the end product being a reactive synthesis gas comprised primarily of Carbon Monoxide and suitable for further catalytic processing targeted on the manufacture of hydrocarbons.

As we indicated in that report, the United States Department of Energy seems to have followed up on those NASA developments, and subsequently, through scientists at their Lawrence Livermore National Laboratory, devised their own technology for gasifying Coal without the co-generation of Carbon Dioxide; and, like NASA, doing so by using solar heat to drive the process, so that any Coal combustion for the generation of thermal energy, with some concurrent CO2 generation, is unnecessary; and, with the end product being a reactive, industrially-useful and commercially-valuable, relatively CO2-free, Carbon Monoxide-based syngas.

Note, though, importantly: In the USDOE technology disclosed by the US Patent we submit herein, plain old Steam, i.e., H2O, is added to the hot, reactive Coal gases, so that a fully-hydrogenated, but hydrocarbon-free, hydrocarbon synthesis gas can be produced.

The DOE are exposing a technology wherein all of the original carboniferous and hydrocarbon content of Coal is broken down into justCarbon Monoxide and Hydrogen, which can then be catalytically recombined to synthesize desired hydrocarbons. There is no still-carbonaceous residue left by the original gasification, which, if you recall earlier of our reports, such as those, just as one example, concerning the Government's sponsorship of the COED project in New Jersey, was a factor in precedent Coal gasification technologies.

And, perhaps more importantly:

 

Carbon Dioxide can, as well, be added to those Coal gasses, along with the Steam, to increase the yield of Carbon Monoxide-Hydrogen synthesis gas.

Additionally, of further import is the fact, in confirmation of many of our earlier reports, that some types of Carbon-recycling biomass can be added to the primary Coal raw material, and converted thereby into that hydrocarbon synthesis gas.

Note, that, since the baseline CO2 emission from the USDOE's Coal-based process is, in theory, zero; then, the addition of either biomass, through the underlying photosynthesis that formed the biomass, or, of straight Carbon Dioxide combined with Steam, to such a Coal-based process, as specified herein by the USDOE to be feasible and practicable, could actually result in an indirect net reduction in atmospheric Carbon Dioxide, especially if some of the hydrocarbons produced thereby were directed further into the synthesis of plastics in addition to hydrocarbon fuels.

Some additional comment follows excerpts - but, as a foreword, we urge study and contemplation of the USDOE's full "Background" statement - from the initial link in this dispatch to:

"United States Patent 4,415,339 - Solar Coal Gasification Reactor

 

Date: November, 1983

 

Inventors: William Aiman and David Gregg, CA

 

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.

Claims: A method of producing a substantially hydrocarbon-free product gas with a solar reactor from a carbonaceous-material feed ... (and) wherein the feed is coal and includes water, thereby generating steam from said water (and) injecting at least one reactive gas selected from the group consisting of steam, CO2, H2 and CH4 into said solar reactor between said solar energy reactor entry and said gasification zone ... .

A solar carbonaceous-material gasification apparatus, comprising: a solar energy reactor; means for transmitting a feed into said reactor; means for directing solar energy into said reactor onto said feed ...; and, means for withdrawing product gases from said reactor.

The solar gasification apparatus ... including means for injecting steam into said reactor ... .

Background and Prior Art: 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 hydrocarbons or 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. In addition, a substantial fraction of the solar energy is converted into chemical energy in the process, and the converted energy is stored in the product. Since solar energy is used rather than burning part of the coal to provide energy, less coal is required which conserves that resource and reduces potential environmental problems associated with the use of coal proportionately. 

Solar coal gasification systems have been proposed, but all such systems would produce a combination of gases in the product stream. The combinations of gases typically include gases containing hydrocarbons, such as methane. Such hydrocarbon-containing product streams would be highly useful for pipeline quality gas, but would require expensive refining to produce liquid fuels suitable for powering motor vehicles. It is desirable to provide a system for gasifying coal, other hydrocarbons, and/or biomass, and produce a product stream that is free from hydrocarbons ... .

A hydrocarbon gasification system utilizing solar energy is described in U.S. Pat. No. 3,993,458 to Michael J. Antal, Jr., patented Nov. 23, 1976. Steam, CO2, or some mixture of these two gases is heated to a temperature of 600 C. or more in a chemical reactor located at the focus of a tower top solar furnace. This working fluid is used to fluidize a reactant bed of char and organic material. Solid wastes, shredded or unshredded, depending on the economics of the system, are introduced ... .

(Note: Organic wastes, as immediately above, can be included with the Coal feed, and thereby enhance the Carbon-conserving spirit of this Coal conversion system. We believe we long ago reported the above-noted Antal patent to the West Virginia Coal Association, but will reintroduce it in a future report.)

Summary: The present invention provides a solar coal gasification reactor with a pyrolysis gas recycle stream. The pyrolysis gas recycle stream substantially eliminates hydrocarbon in the product stream by steam reformation on hot char. The product is substantially free, if not entirely free, of tar and other hydrocarbons, and thus be suitable for direct use in many processes.

(Just one of those "many processes" for which such Coal based "product" gas would "be suitable" is, we submit, Fischer-Tropsch, or related, catalytic condensation into liquid hydrocarbons.)

It is an object of the present invention to provide a coal gasification reactor that will produce a product stream that is relatively free from hydrocarbons. It is a further object of the present invention to provide a solar coal gasification system that utilizes a pyrolysis gas recycle stream and injected steam ... and/or CO2 ... .

Product gases ... would be very suitable for many purposes, including conversion to methanol."

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So, from a process based on Coal and environmental energy, which could be made to entail, perhaps, a net consumption of added Carbon Dioxide, along with a total consumption of the Carbon content in Coal, we can make Methanol.

We are compelled to remind you:

 

Methanol can be converted, via, for one example, ExxonMobil's "MTG"(r) process, into Gasoline.

 

Methanol can be utilized as the basic raw material in the synthesis of a variety of valuable Plastics.

 

All from Coal, Water and Sunlight, in a process developed, three decades ago, by our tax dollars; and, thus, in theory, owned by us.


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