GB894203A - Improvements in or relating to the recovery of benzole and naphthalene from the crude gas produced and/or treated in coke oven and/or gas works by-product recovery plants - Google Patents

Abstract

<PICT:0894203/III/1> Benzole and naphthalene are stripped from wash oils or oils that have been used for recovering such hydrocarbons from crude coal gas by reusing steam which has been used in one stage of the process for stripping naphthalene from the wash oil, in its naphthalene-bearing condition, for stripping benzole, or benzole and further naphthalene, from the wash oil. In a preferred embodiment crude coal gas from a coke oven 1 passes to a flushing tank 4 and to primary coolers 5 where tar and other liquors are removed via a line 6. The gas passes by means of a line 7 to a benzole scrubber 8 in which the gas is washed with oil primarily to remove benzole, the gas passing to a gas holder through a pipe 11. A branch pipe 12 leads to a naphthalene washer 14 where the gas from the benzole is further washed with oil to remove remaining naphthalene from the gas in order to bring its naphthalene content down to a low level such as to render the gas acceptable for use as town gas. Stills 16 and 17 are provided to strip the wash oil of benzole and naphthalene respectively. The benzole-stripped wash oil for use in the benzole scrubbers leaves the still 16 by a pipe 8 and the benzole bearing wash oil leaves the bottom of the scrubber through a pipe 19 and a heater 20 from whence it is recycled to the top of still 16. To strip naphthalene from naphthalene bearing wash oil the latter is blown with fresh open steam through pipe 24, the naphthalene bearing steam leaving the top of the still through pipes 26 and 27 to the bottom of still 16. The benzole-and naphthalene -bearing steam leaves via a pipe 30 and is separated and the benzole recovered.