GB1107483A - Process for production from petroleum distillates of rich gases interchangeable with natural gases - Google Patents

Abstract

In a cyclic catalytic process for making a gas interchangeable with natural gas by reacting steam with atomized and/or vaporized liquid hydrocarbons which contain up to 0.3% by weight sulphur, the catalyst is such as to (1) promote cracking reactions and direct them preferentially to the formation of methane and ethylene, (2) promote the reaction of cracked hydrocarbons with steam to produce carbon monoxide and hydrogen, and (3) retain almost all the sulphur contained in the feed in the form of sulphides, which are oxidized to sulphur dioxide during the subsequent heating stage and removed with the combustion gases. A suitable catalyst comprises a refractory oxide and/or silicate support (e.g. Al2O3, MgO, ZrO2) and two active metals, one (a) (e.g. Cr, Mn, W) for promoting cracking, and the other (b) (e.g. Ni, Co, Fe, Cu) for promoting steam reforming and retaining inorganic sulphur. Optimum proportions of (a) to (b) are 1.5 to 1 to 3 to 1, and (a) plus (b) should equal from 1 to 10% by weight of the catalyst. Preferred reaction conditions are:-Steam-hydrocarbon ratio 0.5:1 to 1.5:1 by weight; catalyst temperature 600 DEG to 1100 DEG C.; space velocity of 0.5 to 1.5 kg. of feed per litre of catalyst per hour. The product gas should comprise: 20 to 30% H2, not more than 28% olefins, not less than 25% methane (percentages by volume). This gas may be subjected to autohydrogenation at 70 DEG to 200 DEG C. over a suitable catalyst, e.g. one comprising an active metal (e.g. Cu, Ni, Co, Pt, Mo) on an active carbon or silica gel or diatomaceous earth support, to produce a gas consisting essentially of methane and saturated hydrocarbons. A comparative specific example is described.ALSO:A catalyst intended for use in gasifying liquid hydrocarbons, by a cyclic process, see Division C5, comprises a refractory oxide and/or silicate support, e.g. Al2O3, MgO, ZrO2, and two active metals, one, e.g. Cr, Mn, W, for promoting cracking, and the other, e.g. Ni, Co, Fe, Cu, for promoting steam reforming reactions, and for retaining inorganic sulphur (which is oxidised during the heating stages). The metals should amount to 1% to 10% by weight of the catalyst, and the quantity of the cracking metal should be 1.5 to 3 times that of the reforming metal. A specific catalyst comprises (% ages by weight):- 85.2 MgO, 5.6 Fe2O3, 3.2 SiO2, 4.5 Cr2O3, 1.5 Al2O3. The product gas may be subjected to an autohydrogenation step, in which a catalyst comprising an active metal, e.g. Cu, Ni, Co, Pt, Mo, on a support such as active carbon, silica gel or diatomaceous earth is employed.