GB918775A - Process and apparatus for separating tar, naphthalene, ammonia, hydrogen sulphide, hydrogen cyanide and pyridine from coke oven gases - Google Patents

Abstract

918,775. Separating constituents of oven gas. DEUTSCHE GERATEBAU G.m.b.H. May 22, 1959 [May 23, 1958; Jan. 15, 1959], No. 17556/59. Class 55 (2). In a process for separating tar, naphthalene, ammonia, hydrogen sulphide, hydrogen cyanide and pyridine from coke oven gas, in which the hot gases leaving the oven are first pre-cooled by spraying with water and the spray water is separated from the gases, freed from tar condensates, precipitated by the pre-cooling and recirculated to the sprayer, and the pre-cooled gases are then cooled indirectly by one-way plunge cooling to temperatures below 25‹ C. and finally washed with water in an ammonia washer, the aqueous ammonia leaving the washer being conducted to a still, the downwardly flowing gases in the cooler in which oneway plunge cooling is effected are washed in uniflow, after they have cooled to a temperature below 25‹ C. and preferably without further cooling by the downwardly-trickling condensate in the lower portion of the cooler and the condensate leaving the cooler is supplied, in part at least, to the still. As shown in Figs. 2a and 2b, cooler 11 has a lower section 30 operating as a uniflow washer. Lower cooling stage 14 may be operated only when atmospheric temperature requires it e.g. during summer time, cooling stages 12, 13 normally proving sufficient to lower the gas temperature to less than 25‹ C. Condensate flowing from cooler 11 may be caused to enter still 25 via a pipe 31, tar separator 32 and pipe 33. A sufficient quantity of water may be returned from the cooler condensate to the spray water circuit to maintain constant the amount of water in said circuit.