GB335522A - Improvements in the conversion of hydrocarbons of high boiling point range into valuable products, especially those boiling at low temperatures - Google Patents

Abstract

335,522. I. G. Farbenindustrie Akt.- Ges. April 23, 1929. Addition to 296,700. Hydrocarbons, cracking; hydrogenation, destructive.-The process of the parent Specification is modified by subjecting the carbonaceous material to a mild cracking process whereby a far-reaching formation of benzine is avoided, the product remaining after any benzine formed has been separated off being subjected to destructive hydrogenation; residue from the last process may be again cracked and destructively hydrogenated. The initial cracking may be carried out with or without hydrogen, or gases supplying hydrogen or other gases such as nitrogen, water vapour, ethane, methane, ammonia, oxides of carbon &c. The temperatures employed depend on the rate throughout, the pressure and the nature of the extraneousgases employed. Temperatures between 450‹ and 650‹ are employed with a throughput of one cubic metre of treated material per cubic metre of cracking space per hour. Atmospheric pressure may be used, but when no hydrogen is present the pressure may be 50 atmospheres, Somewhat reduced pressure may be necessary where the materials operated on contain a high proportion of low boiling constituents. When hydrogen is used in the extraneous gas, the pressure does not exceed 10 atmospheres so that no destructive hydrogenation of the initial material takes place during the first stages. During this stage, part of the contents may be led out from and back into the heating chamber to effect stirring and minimize the deposition of coke. Catalysts may be employed in all stages, those for the initial stage having a splitting action, such as bauxite, silica gel, active charcoal or alumina, &c. For the destructive hydrogenation, those set forth in Specifications 247,583, 247,584, 247,585, 247,586, 247,587, 249,501, 251,264, 258,272, and- 331,558 may be used. The destructive hydrogenation may be carried out in stages having different conditions of pressure and temperature. In an example, mid-continent gas oil was cracked at 50 atmospheres and 460‹ C. and the whole of the product without reduction of pressure passed into a rectifying column where 25 to 30 per cent of benzine was separated from the higher boiling products; these were subjected to the action of hydrogen at 200 atmospheres and 450‹ C. in molybdenum and zinc oxides. 50 to 60 per cent of the products consisted of benzine, the remainder being a light gas oil which was again cracked to yield benzine.