GB771557A - A process for the reduction of iron catalysts for the hydrogenation of carbon monoxide - Google Patents

Abstract

Iron catalysts prior to their use in the hydrogenation of carbon monoxide are reduced by passing carbon monoxide or a gas containing it over the catalyst at a space velocity greater than 300 and at a temperature within the range 180 DEG to 600 DEG C., the gas being passed over the catalyst at substantially constant velocity from the beginning of the process of reduction. The space velocity is preferably greater than a 1000 volumes per volume per hour and the gas and catalyst are preferably separately heated to the reduction temperature, desirably between 200 DEG and 400 DEG C. The reduced catalyst may subsequently be treated with hydrogen at 250 DEG to 400 DEG C. The reduction may be effected with impure carbon monoxide containing carbon dioxide, or with a synthesis gas which at the high space velocities employed is only slightly converted. The reduction may be carried out in thin layers having a thickness less than 1 m. According to an example, a carrier free iron catalyst containing 0.2 per cent by weight of copper, both the iron and copper being in the form of their carbonates obtained by coprecipitation from a solution of the nitrates, and 0.25 per cent of potassium carbonate was reduced in a synthesis reactor with water gas containing 6 per cent carbon dioxide, 38 per cent carbon monoxide, 47 per cent hydrogen and the rest nitrogen at a temperature of 290 DEG to 310 DEG C. at a space velocity of 3000 volumes per volume per hour. The so-reduced catalyst was used in synthesis with water gas at a gauge pressure of less than 10 atmospheres at 190 DEG to 215 DEG C.ALSO:Iron catalysts prior to their use in the hydrogenation of carbon monoxide are reduced by passing carbon monoxide or a gas containing it over the catalyst at a space velocity greater than 300 and at a temperature within the range 180 to 600 DEG C. the gas being passed over the catalyst at substantially constant velocity from the beginning of the process of reduction. The space velocity is preferably greater than a 1000 volumes per volume per hour and the gas and catalyst are preferably separately heated to the reduction temperature, desirably between 200 and 400 DEG C. The reduced catalyst may subsequently be treated with hydrogen at 250 to 400 DEG C. The reduction may be effected with impure carbon monoxide containing carbon dioxide, or with a synthesis gas which at the high space velocities employed is only slightly converted. The reduction may be carried out in thin layers having a thickness less than 1 m. According to an example a carrier free iron catalyst containing 0.2 per cent by weight of copper, both the iron and copper being in the form of their carbonates obtained by co-preciptation from a solution of the nitrates, and 0.25 per cent of potassium carbonate was reduced in a synthesis reactor with water gas containing 6 per cent carbon dioxide, 38 per cent carbon monoxide, 47 per cent hydrogen and the rest nitrogen at a temperature of 290 to 310 DEG C. at a space velocity of 3000 volumes per volume per hour. The so reduced catalyst was used in synthesis with water gas at a gauge pressure of less than 10 atmospheres at 190 to 215 DEG C.