GB488812A - Improvements in and relating to the purification of combustible gases by washing with oils - Google Patents

Abstract

In the recovery of volatile constituents, e.g. benzol from combustion gases by scrubbing them with wash oil (unsaturated in respect to naphthalene) in the proportions of about 30 gallons of wash oil per 1000 cubic feet of gas, the whole of the absorbed substances are removed from the wash oil in one distillate, which is condensed, fractionally distilled into light and heavy fractions, the heavy fraction being then returned to the stripped wash oil prior to its re-use. Oil from a gas washer is fed by pump 1 through heat exchanger 3 to a spray 5 in the upper end 6 of a column where the oil is preheated by vapours and steam rising through a pipe 8 from the lower part 7 of the column. Water is drawn off through a separator 10 from the condensate formed and the oil is fed from an overflow 11 through spray 12 into the lower section 7 where it is evaporated by direct steam with additional indirect heating if required, the stripped oil being withdrawn through pipe 22 and cooling banks 23, 24. The vapours evolved from the sections 6, 7 pass through pipes 13, 16, 15 and a cooling bank 25 to a pipe 29 for separation of water and redistillation, e.g. by introduction through a spray 30, Fig. 2, into the upper portion of a column 32 surmounting a still 33 heated by a steam coil 34. Fractions of low and high boiling point are withdrawn through lines 35, 37 respectively <PICT:0488812/III/1> <PICT:0488812/III/2> and condensed in cooling coils 36, 38, the heavy fraction being then returned to the stripped oil. Specification 430,989 is referred to.