Sub-bituminous

In absolute terms, the quantities of reactor solids found in various processes do vary considerably. The rate of accumulation is related to several factors, such as coal characteristics, recycle solvent quality and reactor design. However, it can be stated in general terms that liquefaction of low rank coals (sub-bituminous C and lignites) does result in higher rates of accumulation of solids than do similar operations with bituminous coals. For example, during normal operations of the SRC-I pilot plant at Wilsonville, Ala., it has been found that the amount of solids retained varies from about 0.2-0.5 wt.% (moisture-free) for bituminous coals to 1.0-1.9 wt.% (moisture free) for a subbituminous C coal (Wyodak) (72). Exxon also reports much larger accumulations for lignites and subbituminous coals than those found for bituminous coals (73). 

An implication of Cudmore s data (10) for the sub-bituminous and high volatile bituminous coals is that the semi-fusinite as such appears to contribute little to the conversion products, otherwise the apparent dependence of yield on the vitrinite (+ exinite) content would not be so linear. 

Black coal. Black coal ranges from Cretaceous age (65 to 105 million years ago) to mid-Permian age (up to 260 million years ago). They are all black some are sooty and still quite high in moisture (sub-bituminous coal). A common name for this coal in many parts of the world is "black lignite. Coals that get more deeply buried by other rocks lose more moisture and start to lose their oxygen and hydrogen they are harder and shinier (e.g., bituminous coal). Typical energy contents are around 24 to 28 MJ/kg. These coals generally have less than 3% moisture, but some power stations burn coal at up to 30% ash. 

As volatile matter in the coal increases to as much as 40% of the coal (dry and ash-free basis), increasing amounts of oils and tars are released. However, for coals of higher volatile content, the quantity of oils and tars decreases and is relatively low in the sub-bituminous coals and in lignite. 

Transport Reactor Gasifier Coal (sub-bituminous), KY and IL No. 6, coke breeze LHV IGCC 26.8-64... 

H-Coal, A Future Energy Source, "H-Coal Special Issue, 1 Energy Countdown Eccles and DeVaux, "Current Status of H-Coal Commercialization " "H-Coal Plant Sets February Restart Using Western Sub-Bituminous Coal," Energy Insider, February 1982, 5, p 1,... 

The main purpose of magnesia addition to a limestone wet scrubbing system is to facilitate high S02 removal. For a wet scrubber that cleans flue gas from a utility coal-fired boiler, the scrubber inlet gas S02 concentration is typically about 700 ppm by volume per one weight percent sulfur in the fired coal. For sub-bituminous coal having only 0.7 weight percent sulfur content, the inlet S02 concentration is about 500 ppm, and, for example, the outlet S02 has to be less than 50 ppm to achieve 90 percent removal. In order to avoid serious inhibition of mass transfer because of S02 back-pressure, the equilibrium S02 partial pressure should be about four or more times lower than the actual S02 partial pressure in the gas. Thus, Figure 3 indicates that for this low-sulfur coal system, the scrubber inlet pH should be at least 5.5, and the outlet pH at least... 

Figure 1. M2x pyrograms of a brown coal (R30) (A), its extracted residue (B), and samples of Collie (C) and Amberley (D) sub-bituminous coals. Analytical data in Table I.

The fuel burned in the present experiments was a Utah sub-bituminous coal containing 10.16 percent ash. Its properties are summarized in Table I. 

Lignite (Brown Coal). A brownish-black coal in which the alteration of vegetable matter has proceeded further than in peat, but not as far as in sub-bituminous coal. There is no sharp distinction between these three materials, but in general, lignite is denser, darker in color, and contains more C than peat. Lignite consists of w 9—12, vol comb matter 31—38, fixed C 27—43, and ash 5-20% (Ref 3)... 

Leachability of trace elements from CCP is a function of their type and hydration behaviour. The leachability of metals from lignite and sub-bituminous CCP is lower than from bituminous CCP due to the formation of hydrated minerals. Leachability of Se and B from Fort Union and PRB CCP is probably controlled by metal substitution within the ettringite crystal structure (Hassett Hassett 1988 Hassett et al. 1989 Kumatharasan et al. 1990 Solem-Tishmack... 

Praharaj, T., Powell, M. A., Hart, B. R. Tripath y, S. 2002. Leachability of elements from sub-bituminous coal fly ash from India. Environment International, 27, 609-615. 

Bituminous Coat. Coal that ranks between sub-bituminous coal and semibituminous coal and that contains 15-20% volatile matter. It is dark brown-to-black in color and bums with a smoky flame. Bituminous coal is the most abundant rank of coal and is commonly Carboniferous in age. The most common synonym is soft coal. 

Sub-bituminous Coal. A black coal intermediate in rank between lignite and bituminous coals, or in some classifications, the equivalent of black lignite. It is distinguished from lignite by higher carbon content and lower moisture content... 

The sub-bituminous coals are further classified in terms of their calorific value ... 

Sub-bituminous A Coal—A type of sub-bituminous coal having 10,500 or more, but less than 13.000 Btu per pound (5838-7228 Calories/kg). 

Lignite Coal. A brownish-black coal that is intermediate in coalihcalion between peat and sub-bituminous coal consolidated coal with a calorific value less than 8,300 Btu per pound (4615 Calories/kg), on a moist, mincial-matter-free basis. Synonyms include brown lignite and brown coat. Further classifications of lignite are made on the basis of calorific value ... 

During the Cretaceous period which dates back approximately 100 million years. Deposits include the predominately bituminous and sub-bituminous coal beds in the Rocky Mountain Province, extending in large, separated regions from central Montana into northeastern Arizona and northwestern New Mexico. 

During the Tertiary period which dates back approximately 65 million years. Deposits include the sub-bituminous coal and lignite beds in the Great Plains Province, which includes northeastern Wyoming, eastern Montana, western North Dakota, and northwestern North Dakota. 

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