1271.    GROSS, H. W.  [Production of Detoxified City Gas by Pressure Gasification and Synthesis With Iron Catalysts.]  Erdöl u. Kohle, vol. 3, No. 1, 1950, p. 11; No. 5, 1950, pp. 218-222; Chem. Abs., vol. 40, 1950, p. 7513.

       Abstract of paper presented at the 1949 meeting of the Deutsche Gesellschaft Mineraloelwissenschaft u. Kohlechemie.  Previous processes for the detoxification of city gas, such as the conversion of CO with steam to H₂ and CO₂ or the washing out of CO with Cu salts, have only occasionally been used since they, in general, raise the cost of the gas too greatly.  Since 1938 the Lurgi Ges. für Wärmetechnik m. b. H. has been working on a process that changes the poisonous CO with a small amount of the H₂ in the gas into a more valuable Fischer-Tropsch product.  In most cases the detoxified gas is cheaper, since the net excess for the production of hydrocarbons, in general, exceeds the cost of the used gas.  This method, therefore, is of great interest, since it places gas detoxification on an economical basis.  Especially favorable is the relation in the working up of city gas from the Lurgi pressure gasification plants since this gas possesses a relatively high CO content of 15-20% and a favorable pressure of 20 atm. for the catalytic conversion to hydrocarbons.  Special Fe catalysts are used which need for the reaction, beside CO, only a little H₂.  Because of the equalizing effect in the gas contraction associated with the reaction the H₂ content in the detoxified gas remains virtually the same, and the end gas still corresponds to a normal city gas.  In 1942 the process was experimentally tested at Bohlen near Leipzig on a large scale processing 1,600 N m.³ of gas per hr.  Several months operation showed that, depending on the catalyst composition and the operating conditions, mainly paraffin or low-boiling hydrocarbons could be obtained.  Since CH₄ formation in the synthesis is favorable to the city gas, the yield per N m.³ of gas used, is far above 200 gm.