PATENTS

3214.  RUPP, W. H. (Standard Oil Development Co.) Gases Rich in Hydrogen.  United States Patent 2,514,340, July 4, 1950; appl. filed Dec. 22, 1948, Serial No. 66,613; 10 claims (Cl. 260-450).  Chem. Abs., vol. 44, 1950, p 8625.

Tail gases from hydrocarbon synthesis with CO and H₂, amounting to 5,000-10,000 cu. ft.  per bbl. of liquid products, after condensation of liquid hydrocarbons, are relatively low in H₂ and CO content and high in CO₃, N₂, and unsaturated hydrocarbons, so that this gas is unsuitable for recycling.  CO₂ and hydrocarbons of 3 or more C atoms are scrubbed from 1 part of this gas (10-30%) at a pressure of 100-500 p.s.i. and at 50°-150° F. with an absorbent oil (which may be a 150°-500° F. or narrower cut from petroleum or synthesis oil).  The quantity of oil used is 40-200 gal. per 1,000 cu. ft. of total tail gas scrubbed and all of it  is used in each stage.  The gas from this 1^st step has a H₂ content of about 50%, about 2 times that of the tail gas, and can be used for many hydrogenation purposes or as a makeup gas in the hydrocarbon synthesis.  The rich oil is then used to removed hydrocarbons from the larger part of the tail gas, preferably by using the same temperature and pressure conditions as in the 1^st stage.  The rich oil from the 2d stage is then stripped to remove CO₂ and hydrocarbons.  The gas from the 2d step may be used as a fuel or, in certain cases, used as a makeup gas after removing CO₂ by conventional means.