Coal liquefaction commercial operations

Status of Indirect Liquefaction Technology The only commercial indirect coal liquefaction plants for the production of transportation fuels are operated by SASOL in South Africa. Construction of the original plant was begun in 1950, and operations began in 1955. This plant employs both fixed-bed (Arge) and entrained-bed (Synthol) reactors. Two additional plants were later constructed with start-ups in 1980 and 1983. These latter plants employ dry-ash Lurgi Mark IV coal gasifiers and entrained-bed (Synthol) reactors for synthesis gas conversion. These plants currently produce 45 percent of South Africa s transportation fuel requirements, and, in addition, they produce more than 120 other products from coal. 

Hydrogen sulfide is a by-product of many industrial operations, eg, coking and the hydrodesulfurization of crude oil and of coal. Hydrodesulfurization is increasing in importance as the use of high sulfur crude oil becomes increasingly necessary (see Petroleum, refinery processes). A large future source of hydrogen sulfide may result if coal liquefaction attains commercial importance (see Coal CONVERSION processes). 

ER E discussions with Texaco and with Shell on bottoms processing are summarized herein. Texaco has indicated that its partial oxidation process could be applied to coal liquefaction bottoms on a commercial scale and that operation of their 12 T/D pilot plant with coal liquefaction bottoms representative of a projected commercial feedstock would be adequate to set the design basis for a commercial facility. Texaco indicated that three to four years after successful operation of the 12 T/D unit a commercial facility could be ready for startup. In initial discussions, Shell has indicated that development of the Shell/ Koppers partial oxidation process for coal liquefaction bottoms would involve operations of both their 6 T/D pilot plant and their 150 T/D demonstration unit. It was estimated that the 150 T/D facility might become available in the late 1980/early 1981 time frame for possible operation on vacuum bottoms. 

In conclusion, increased understanding of the requirements for successful development of coal liquefaction for a wide variety of coals has been achieved. Operations of the large liquefaction and FLEXICOKING pilot plants, scheduled to begin in 1980 and 1981, should provide the data base needed for scale up to commercial size. 

The work reported here was carried out in two phases. The first phase was conducted in a laboratory test boiler to determine the relative PNA emissions from a variety of EDS and petroleum fuels. The second phase of testing was conducted in a commercial boiler to determine the effect of unit size on PNA emissions. This testing was made possible by the start-up and operation of the Exxon Coal Liquefaction Pilot Plant (ECLP) which has a throughput of 250 tons per day and can produce approximately... 

Britain and Germany had the most successful synthetic fuel programs. The others were either smaller-scale operations, such as France s three demonstration plants (two coal liquefaction and one F-T), Canada s bitumen liquefaction pilot plants, and Italy s two crude petroleum hydrogenating (refining) plants, or technological failures as were Japan s five commercial-size plants (two coal liquefaction and three F-T) that produced only about 360,000 barrels of liquid fuel during the World War II years [2]. 

The absorption in alkanolamine solutions (MEA, DEA, ADIP, DGA, etc.) is the commercially most important process for the removal of CO2 from synthesis gas for ammonia and methanol production, for the production of hydrogen, in natural gas purification, coal liquefaction, and the like. In the present example a gas containing 13.55 mole-% of CO2 is to be purified by absorption into an aqueous solution of 13.6 wt-% MEA. The column, filled with 0.05 m steel Pall rings, has a diameter of 1.05 m and is operating at a temperature of 315 K and a pressure of 14.3 bars. The inlet flow rates of gas and liquid are 497 kmol/h and 76.9 mVh, respectively. Determine the packed column height necessary to reduce the mole fraction of CO2 to 5 x 10 at the top of the column. 

In addition to scale-up difficulties, there are a number of problems related to the stable operation of a bubble column associated with hydrodynamics. For example, consider the important commercial application of bubble columns in hydroprocessing of petroleum resids, heavy oils and synthetic crudes. Hydrodynamic cold flow and hot flow studies on the Exxon Donor Solvent coal liquefaction process (Tarmy et al., 1984) showed that much of the literature correlations for the hydrodynamic parameters (holdup, interfacial area and dispersion coefficients) obtained with cold flow units, at ambient conditions, are not applicable for commercial units operating at relatively higher pressures. In addition, the flow pattern in commercial units was considerably different. In the hydroprocessing of petroleum residues by the H-Oil and LC-Fining processes, refinery operations have experienced problems with nonuniform distribution of gas and liquid reactants across the distributor, maintaining stable fluidization and preventing temperature excursions (Beaton et al., 1986, Fan, 1989 and Embaby, 1990). Catalyst addition, withdrawal and elutriation have also been identified as problems in these hydrotreaters. 

Liquefaction. Liquefaction of coal to oil was first accompHshed in 1914. Hydrogen was placed with a paste of coal, heavy oil, and a small amount of iron oxide catalyst at 450° and 20 MPa (200 atm) in stirred autoclaves. This process was developed by the I. G. Earbenindustrie AG to give commercial quaUty gasoline as the principal product. Twelve hydrogenation plants were operated during World War II to make Hquid fuels (see CoAL... 

Energy demand, the implementation of sulfur oxide pollution controls, and the future commercialization of coal gasification and liquefaction have increased the potential for the development of considerable supplies of sulfur and sulfuric acid as a result of abatement, desulfurization and conversion processes. Lesser potential sources include shale oil, domestic tar sands and heavy oil, and unconventional sources of natural gas. Current supply sources of saleable sulfur values include refineries, sour natural gas processing and smelting operations. To this, Frasch sulfur production must be added. 

Some consideration ought to be given to designing a first commercial or demonstration plant to maximize operability rather than profitability. This can perhaps be done by seeking out the areas of high process severity and backing off to milder operating conditions. For example, in each of the liquefaction processes that are considered to be relatively advanced, H-Coal,... 

The direct liquefaction technologies, which include Solvent Refined Coal, Exxon Donor Solvent and H-Coal processes have never been operated at a commercial scale. As discussed yesterday, these processes are not at advanced stages of development. The products from direct liquefaction processes are basically boiler fuels or synthetic crudes that could potentially be upgraded to... 

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. 

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