| 摘要 |
1,252,469. Water gas shift reaction. ESSO RESEARCH & ENG. CO. 24 March, 1969 [8 April, 1968], No. 15234/69. Heading C1A. Hydrogen is prepared by passing a gaseous mixture comprising carbon monoxide, steam and a small amount of sulphur impurities over a catalyst comprising an alkali metal salt derived from an acid having an ionization constant of less than 1 x 10<SP>-3</SP>, the carbon dioxide concentration in the gas mixture being maintained at at least 5 mol per cent. The CO 2 concentration is maintained at at least 5% by recycling CO 2 , by the addition of extraneous CO 2 , or by carrying the reaction out in two stages, the first at 700- 900‹ F. to effect partial conversion of CO to CO 2 and the second at 500-650‹ F. to complete the reaction. In this embodiment, the feed is partially converted to CO 2 in a high temperature stage using a suitable catalyst such as Fe 2 O 3 promoted with Cr 2 O 3 . When the partial conversion in this first stage results in the CO 2 concentration which is required for the second stage, this mixture is fed into a low temperature reactor preferably at 400-700‹ F. and passed over a catalyst consisting of an alkali metal salt. Salts specified are the carbonate, biphosphate, aluminate, hydroxide, acetate etc. of sodium, potassium, lithium, rubidium and caesium. Caesium and potassium carbonates are particularly preferred. |
