| 摘要 |
1,187,676. Benzene; town gas. UNIVERSAL OIL PRODUCTS CO. 18 Aug., 1967 [19 Aug., 1966], No. 38051/67. Heading C5E. Town gas and a benzene concentrate are formed by a process in which: (1) a hydrocarbon is cracked with steam and the cracking fraction is separated into a hydrogen-rich stream and a carbon dioxide-rich stream; (2) a hydrocarbon containing naphthenic and paraffinic hydrocarbons is reformed in the presence of at least a portion of the hydrogenrich stream produced in (1 to provide a product containing alkyl aromatic hydrocarbons; (3) these alkyl aromatic hydrocarbons are dealkylated to provide (a) a liquid product stream containing benzene and (b) a low purity gas stream containing 40-70% by volume of hydrogen; (4) the low purity gas stream produced in (3) is separated, e.g. cryogenically, into a relatively high purity hydrogen stream, e.g. comprising at least 80% hydrogen, and a stream comprising light paraflinic hydrocarbons; (5) at least a portion of the relatively high purity hydrogen stream produced in (4) is supplied to the reforming step (2); and (6) the stream comprising light paraffinic hydrocarbons separated in (4) is mixed with a proportion of the carbon dioxide rich stream produced in (1) to provide a town gas. In step (1) a naphtha is cracked at 316-982‹ C. using a nickel catalyst and a mole ratio of steam to carbon of 1-5 ; :1 to 5.0 1 and the carbon monoxide produced is oxidized with an iron-oxide catalyst to carbon dioxide which is removed by absorption in triethanolamine. In step (2) a naphtha boiling at 38-232‹ C. is reformed at 260-566‹ C. using a catalyst of 0.05 to 5 wt. per cent of platinum on alumina and a hydrogen to hydrocarbon mole ratio of 0-5 : 1 to 15 : 1. In step (3) the dealkylation is carried out at 538-980‹ C. using a hydrogen/ hydrocarbon mole ratio of 3 :1 to 25 :1 and may be either thermal or catalytic using as a catalyst 10-15 wt. per cent of chromium oxide on alumina.
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