GB1420317A - Method of performing a steam reforming reaction - Google Patents

Abstract

1420317 Catalytic reformation BRITISH GASCORP 31 Jan 1973 [10 Feb 1972] 6309/72 Heading C5E Vaporizable hydrocarbon feedstock and steam are reacted to produce methane, hydrogen and carbon oxides employing a reforming catalyst of the type which, in use, suffers from inactivation as a result of the formation thereon of submicroscopic layers of material from constituents of the feedstock, by (1) passing the reactants through a first bed of catalyst to effect the steam reforming reaction until the activity of the bed has substantially deteriorated, (2) then switching the stream of reactants to a second bed of catalyst to effect the steam reforming reaction in the second bed until the activity of the second bed has substantially deteriorated, the product gas from the second bed being passed through the first bed to regenerate catalytic activity in the first bed, and (3) then switching the stream of reactants to the regenerated first catalyst bed and continuing the steam reforming reaction in the regenerated bed. The beds of catalyst provide an initial reserve of catalyst downstream of the end of the reaction zone as at first established and the stage (1) reaction may be carried out until a major proportion of the initial reserve has become deactivated. During stage (2) the second bed and first bed are used in series and as the activity of the second bed deteriorates, the incompletely reacted reactants and the product gas may be passed from the second bed to the regenerated first bed when the steam reforming reaction is completed. When the activity of the second bed has substantially deteriorated, the bed may be withdrawn from operation and the stream of reactants passed directly to the regenerated first bed, and either the vessel containing the second bed recharged with fresh catalyst or the second bed regenerated in situ by passing therethrough product gas from the regenerated first bed, and the operating cycle repeated. The catalyst of the first and/or second bed may be a coprecipitated nickel-alumina catalyst containing an addition of 0À75 to 8À6% by wt. of an oxide, hydroxide or carbonate of an alkali metal or alkaline earth metal calculated as metal based on the combined weight of nickel and alumina, e.g. 70 to 75% nickel, 0À8% potassium, the balance being alumina; or a coprecipitated nickel-alumina catalyst containing at least 40% nickel and 0À10 to 0À75% alkali metal oxide, hydroxide or carbonate, the percentages being by weight of metal based on the combined weight of nickel and alumina, e.g. 70 to 75% nickel, 0À2% potassium, the balance being alumina. The beds may be maintained at 400 to 600‹ C. and up to 70 atmospheres during the steam reforming reaction and the steam : hydrocarbon feedstock ratio may be 1À6 to 5À0 1b./1b., e.g. the reactants may be passed to the first bed at a preheat temperature of 400 to 450‹ C. and a steam : hydrocarbon feedstock ratio of 1À6 to 2À0 1b./1b. The reactants from stage (1) may be passed to the second bed at a preheat temperature of about 450‹ C. During stage (2) the second bed product gases are cooled to about 400‹ C. before being used to regenerate the first bed.