GB1481695A - Gas extraction of coal - Google Patents

Abstract

1481695 Extraction of soluble components from coal COAL INDUSTRY (PATENTS) Ltd 13 Nov 1974 [17 Dec 1973 9 Aug 1974] 58350/73 and 35243/74 Heading C5E In a process for the gas extraction of soluble constituents of coal which comprises heating the coal in the presence of an extractant to a terminal temperature of 400-550‹ C. at which the extractant is in the gas phase, separating the extractant and extract from the residue and thereafter recovering the extract from the extractant, the heating of the coal in the presence of the extractant is carried out at an initial rate of at least 20‹ C. per minute up to an intermediate temperature of 370-390‹ C. and thereafter heating to the terminal temperature is carried out at less than 20‹ C. per minute. The extractant used can comprise components having critical temperatures of 150-550‹ C.; the solvent components listed are water, aromatic, alicyclic and acyclic hydrocarbons, oxygencontaining compounds such as phenols, nitrogen-containing compounds, chlorobenzene and alkylthiophenes. In examples, the solvents used are toluene, o-xylene, pyridine, n-dodecane, methyl ethyl ketone, and an alkyl aromatic mixture having 95% boiling between 165‹ and 167‹ C. Fig. 1 (not shown) illustrates a process in which a mixture of coal and extractant is heated to the intermediate temperature and then passed downwardly through a shaft extractor in countercurrent to an upwardly moving stream of extractant which has been heated to the terminal temperature. Fig. 2 illustrates a process in which a mixture 33 of coal and extractant is heated to the intermediate temperature in a fluidized bed 35 and then further heated and extracted in a series of fluidized beds 40 and 48 in which heat is supplied by the hot extractant from the heaters 43 and 47 which fluidizes the beds.