GB863812A - An apparatus for purifying crude benzene - Google Patents

Abstract

<PICT:0863812/IV (b)/1> In the refining of crude benzene with hydrogen-containing gas in the presence of a catalyst which is a metal of Group 5, 6 or 8 or oxide thereof wherein unconsumed hydrogen is recycled the removal of nitric oxide and carbon monoxide if present from the make-up hydrogen-containing gas is effected in a conduit-like chamber arranged axially with and inside the reactor and filled with a further quantity of said catalyst and constructed in such a manner that the working pressure in the chamber may be different from that in the reactor, and the fresh gas is passed through the chamber, preferably at 10-16 atmospheres, and then brought to hydrofining pressure before being combined with recycle gas. Fresh hydrogen-containing gas enters by line 11, is partially compressed in the multistage compressor 12, heated and mixed with steam if carbon monoxide is present in the device 14, passed through the catalyst chamber 7 disposed within the reactor 1 and therefore heated by heat exchange with the reactants therein which are introduced at 310-320 DEG C. and are further heated in the reactor to 350-360 DEG C. The effluent may be cooled in the cooler 16 and is further compressed to 40-50 atmospheres before being mixed with recycle gas and vapourised impure benzene entering by line 4 at 310-320 DEG C. By performing the prior purification of the gas at a lower pressure than the hydrofining, the formation of polymerisation products by nitric oxide present (which is also removed by the purification) is prevented. Specification 844,380 is referred to.