GB676635A - Improvements in or relating to hydrocarbon synthesis - Google Patents

Abstract

A process of synthesizing hydrocarbons, oxygenated hydrocarbons and mixtures thereof from CO and H2 in the presence of a fluidized iron catalyst, wherein a stream of reactant gas containing a substantial proportion of H2 and CO is passed in contact with said catalyst under predetermined conditions of reaction, including an elevated temperature effective to form such products, a substantial portion of the CO is converted, and the products are withdrawn from contact with the catalyst, is characterized by regulating the time of contact between the reactant gas and the catalyst so that the withdrawn stream of products contains between about 1 and 3 per cent by volume of CO, and recovering the products from the withdrawn stream. Within the stated range it is preferred that the product stream contains not less than about 2 mol. per cent of CO. Advantageously the total mol. per cent of CO in the feed is not substantially greater than about 15 per cent of the total gas feed and is preferably not less than about 5 mol. per cent greater than that in the effiuent. The water content should be as low as possible and not greater than 3 mol. per cent. Preferably the feed contains an H2 : CO ratio of substantially above 2.5 : 1, preferably above 3 : 1, e.g. 4 or 5 : 1. Preferably upwards of about 15 per cent of CO2 should be present. Inert gas diluents may be used and gaseous reaction products recycled. Temperatures, pressures and catalysts usual in the art are employed. Aliphatic alcohols, organic acids, ketones and aldehydes are mentioned as oxygen-containing compounds produced. In an example the catalyst is iron powder with K2O and Al2O3 promoters and is conditioned prior to reaction, the feed is about 30.6 per cent CO, about 64.3 per cent H2, the remainder being CO2, CH4 and N2, reaction is at 650 DEG F. and 250 p.s.i. with a linear gas velocity of 1.2 feet per second, and the effluent gases contain about 2.3 per cent of CO, the contact time being approximately 25 seconds and the products liquid hydrocarbons. In a comparative illustration reaction is effected to give effluent gases containing about 0.7 per cent CO and in a further example, a portion of the effluent, after product separation, is recycled to the fresh feed in a ratio of 1 : 1 and the combined feeds treated as in the first example.