Indirect Liquefaction Processes

So if you don t consider it a broad application for everybody, but instead a single demonstration of a type, be it direct liquefaction or indirect liquefaction process, I think this is a very likely thing and something that we intend to pursue. 

The indirect liquefaction processes include Fischer-Tropsch and coal to methanol. Both processes have operated on a commercial scale. For the past 25 years, a Fischer-Tropsch facility has operated in South Africa. Presently the South Africans are constructing an advanced and larger facility. Coal-to-methanol plants existed in the United States, but were replaced by natural gas-to-methanol facilities because it was more economical to do so. 

Why is it, if indirect liquefaction processes are technically proven, the demand exists and is getting stronger for petroleum substitutes and there is so much coal available to us that people aren t standing in line to build coal liquefaction facilities in the United States today The answer is fairly simple. There are so many uncertainties associated with commercialization — not only technological, but also institutional, legal and regulatory— that the large capital investments required seem too risky to make. Coal liquefaction facilities are capital-intensive with cost in excess of 1 billion. 

Indirect liquefaction processes were developed in Germany around the same time as direct liquefaction processes. In the early 1920s, Franz Fischer and Hans Tropsch patented a process to produce a mixture of alcohols, aldehydes, fatty acids, and... 

Biomass Gasification-Indirect Liquefaction Process Development Units (PDUs)... 

Today, Sasol produces the equivalent of 150,000 barrels per day of fuels and petrochemicals from coal via its indirect liquefaction process. 

The production of liquid fuels—gasoline and diesel—from coal is not a new process. The first patent was registered in 1913, with the more common Fischer-Tropsch indirect liquefaction process patented in 1925. 

INDIRECT LIQUEFACTION PROCESSES 19.5.1 Fischer-Tropsch Process... 

Indirect Liquefaction Process for converting coal into oil or synfuel by first gasifying it also know as the Fischer-Tropsch method. 

The economics of a coal pyrolysis process to cream-off the liquids, utilizing mild conditions (less sophisticated and thus less expensive systems than direct or indirect liquefaction processes) before char is combusted or gasified, can be quite attractive. A number of process streams can be considered for efficient use of all generated solid, liquid, and gaseous products. For example, chars can be sold to offset the production costs of pyrolysis liquids. The gases produced can be combusted to supply the heat generated for the pyrolysis process. 

In liquefaction systems wood and wood wastes are the most common fuelstocks. They are reacted with steam or hydrogen and carbon monoxide to produce liquids and chemicals. The chemical reactions that take place are similar to gasification but lower temperatures and higher pressure are used. Liquefaction processes can be direct or indirect. The product from liquefaction is pyrolytic oil which has a high oxygen content. It can be converted to diesel fuel, gasoline or methanol. 

We will examine three synthetic fuel scenarios and compare their implications regarding sulfur availability with the current and projected market for sulfur to the year 2000. The analysis will consider three production levels of synthetic fuels from coal and oil shale. A low sulfur Western coal will be utilized as a feedstock for indirect liquefaction producing both synthetic natural gas and refined liquid fuels. A high sulfur Eastern coal will be converted to naphtha and syncrude via the H-Coal direct liquefaction process. Standard retorting of a Colorado shale, followed by refining of the crude shale oil, will round out the analysis. Insights will be developed from the displacement of imported oil by synthetic liquid fuels from coal and shale. 

The plant processes 26,840 TPSD of low sulfur North Dakota lignite. The sulfur is 1.3 wt%/DAF coal. The coal analysis is shown in Table II. Output from the plant is 268,700 MM Btu/day of SNG, equivalent to 45,000 BOE/day. Total production of by-product elemental sulfur is 161 tons/day. This represents 78 wt% of total sulfur input from the coal feedstock. Since goal gasification and indirect liquefaction facilities are most likely to use Western low sulfur lignite or subbituminous coals, this represents the low sulfur case for coal conversion. 

The three principal routes by which liquid fuels can be produced from coal have been noted to be pyrolysis, direct liquefaction, and indirect liquefaction. A clean fuel that is a solid at room temperature can also be produced by direct liquefaction processes. 

An indirect liquefaction procedure of relatively recent origin is the Mobil M process for the conversion of methanol to gasoline following the reaction... 

We have our work divided into process engineering, process chemistry, catalysis, and support technology. As an example, one of the indirect liquefaction projects, tube wall reactor, deals with the design and operation of high thermal efficiency catalytic reactors for syn-gas conversion. Other activities are coal liquefaction properties of coal minerals, the role of catalysts, coal liquid product stability, and environmental impact—to name a few. 

In the field of coal liquefaction, many processes exist to convert coal to liquid and gaseous products. These processes can be categorized as direct and indirect liquefaction. 

Because of the advanced stage of development of indirect liquefaction resource applications in DOE are aggressively pursuing the commercialization of the indirect processes. 

Background Indirect coal liquefaction differs fundamentally from direct coal liquefaction in that the coal is first converted to a synthesis gas (a mixture of H2 and CO) which is then converted over a catalyst to the final product. Figure 27-9 presents a simplified process flow diagram for a typical indirect coal liquefaction process. The synthesis gas is produced in a gasifier (see a description of coal gasifiers earlier in this section), where the coal is partially combusted at high temperature and moderate pressure with a mixture of oxygen and steam. In addition to H2 and CO, the raw synthesis gas contains other constituents (such as CO2, H2S, NH3, N2, and CH4), as well as particulates. 

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