首页>
外国专利>
Improvements relating to the treatment of gas works effluent
Improvements relating to the treatment of gas works effluent
展开▼
机译：煤气厂污水处理方面的改进
展开▼
页面导航
摘要
著录项
相似文献
摘要
PICT:0636704/III/1 Ammonium chloride and other constituents are recovered from gas works effluent by washing the raw ammoniacal liquor with benzole to remove monohydric phenols, distilling off free ammonia, concentrating the spent liquor by evaporation, removing higher phenols by solvent extraction, crystallizing ammonium chloride from the resulting liquor and separating the phenols from the solvents. As shown, raw liquor from tank a is washed with benzole from c in a tower b. The benzole is recovered in still d and returned to storage at f while the phenols pass to receiver g by way of a finishing still wherein further benzole is recovered and returned to f. The washed liquor from b is concentrated in a plant comprising a heat exchanger h, reflux heat exchanger i, dissociator j in which free CO2 and H2S are separated from the liquor by spraying the latter at 90 DEG C. on to coke, and still k from which steam, introduced at the bottom, leaves with ammonia at the top and passes through exchangers i and h and a condenser to a tank m, from which any benzole that has been carried over is returned to f. A portion of the spent liquor from k is withdrawn, cooled at o and returned to an ammonia washing plant, while the remainder is concentrated in evaporator n, cooled at p and washed at q with butyl acetate from r, the solvent being recovered in still s and returned to storage at u, higher phenols being passed to tank t. The spent liquor from q then passes through heat exchangers 10 and 11 to a solvent recovery still v, the solvent condensed at 12 and separated at 13 being returned to tank u, while water separated at 13 is returned to the outlet from evaporator n. The spent liquor from v is evaporated in a vacuum crystallizer w from which ammonium chloride passed to centrifuge z, mother liquor being collected in z1. Condensates from w and n are pumped either to an ammonia washing plant or through an active carbon filter y to water drains. The mother liquors gradually build up in thiocyanate and thiosulphate and may be drawn off and concentrated.ALSO:In recovering ammonium chloride (see Group III) and other constituents from gas works effluent, the raw ammoniacal liquor is washed with benzole to remove monohydric phenols, the spent liquor is then distilled to remove free ammonia, concentrated by evaporation and higher phenols are then removed by extraction with butyl acetate. The phenols are separated from the solvents.
展开▼
