GB1447974A - Process for the production of gases containing methane from hydro carbons - Google Patents

Abstract

1447974 Methane-containing gases BRITISH GAS CORP 9 Nov 1973 [13 Nov 1972] 52382/72 Heading C5E Methane-containing gases are produced by the reaction of a feedstock comprising light paraffin hydrocarbons, e.g. naphtha, or methanol with steam, by passing the feedstock in the vapour phase, and steam into a bed of a nickel catalyst at a temperature of at least 300‹ C., such that the bed is maintained at a temperature within the range 400-550‹ C., and recycling at least a portion of the hot methane steam containing gases by mixing the recycled portion with further feedstock vapour and steam and passing the resulting mixture through the bed of nickel catalyst to produce further methane, the recirculation of the reaction gases being achieved by means of a vapour driven jet pump. The drive vapour for the jet pump is the process steam which is added to the recycle gas, with the additional feedstock admixed with the recycle gas at a point intermediate the jet pump and the catalyst bed, or a mixture of feedstock vapour and steam which is added to the recycle gas prior to the further catalysed reaction. The process may take place in an apparatus comprising a source of high pressure steam 1, a source of vapourized feedstock, e.g. hydrodesulphurization vessel 5, a nickel catalystcontaining reactor 7, means for recycling at least a portion of the reaction gas derived from the reactor to a vapour driven jet pump 2, which pump when in use is capable of being driven by high pressure steam from the source thereof, means for conveying the steam and recycled gas together with the feedstock from the region of the jet pump to the reactor and means, e.g. superheater 6, for maintaining the temperature of the total feed to the nickel catalyst in the reactor at at least 300‹ C. The product gas may be recycled via waste heat boiler 8, feed water heaters 9, knock-out pot 10, and flow control valve 4, or directly from reactor 7 via a cooler. The jet pump comprises a cylindrical section of frusto-conical shape connected by its narrower end to a substantially cylindrical mixing throat, there being disposed centrally in the frustoconical section a jet for the provision of high pressure steam, which jet terminates just before the mixing throat, and there being provided means for introducing recycled gas into the frusto-conical section.