GB342359A - Improvements in the treatment of hydrocarbons - Google Patents

Abstract

Unsaturated hydrocarbons; aromatic hydrocarbons.-Homologues of methane e.g. ethane, propane, and butane, are treated in the gaseous phase to produce (a) olefines and diolefines, e.g. butadiene and acetylene (b) aromatics such as oils containing benzene. The materials treated may consist of pure hydrocarbons, mixtures thereof with one another, or mixtures containing diluents, for example, methane. The hydrocarbons are passed through a heated space at 1000-1200 DEG C. or more, and at a space velocity of 50 to 100 or 200, or even several thousand reciprocal minutes. Packing of the reaction chamber should not be used, and catalysts are usually unnecessary, although the walls may exert a catalytic influence. Suitable gases for treatment are natural gases, or gases from the destructive hydrogenation of coal, gases from oil-cracking plants and other hydrocarbons with at least two carbon atoms in the molecule. The reaction vessel may be a carborundum vessel one inch wide, or the plant material may be bonded graphite or heat-resisting alloys such as alloy steels e.g. nickel chromium or chromium steels. The reaction chambers should be very narrow in relation to their length or width. An increased yield of naphthalene is obtained by using reaction vessels whose walls are constructed of or lined with an alumino-silicate refractory such as the mineral sillimanite. In some cases other hydrocarbons such as anthracene are formed. The reaction vessel can be externally heated, or internally by means of radiation from an electrically heated member, or by an inner tube through which heating gases flow. In the example, pure propane is treated at 1150 DEG C., the space velocity being 300 reciprocal minutes. The yield of oil, which is largely benzene or its homologues, is 0,65 gallons per 1000 cubic feet of gas. The exit gas contains hydrogen, unsaturated hydrocarbons and hydrocarbons mainly lighter than propane. At a space velocity of 350 reciprocal minutes, the yield of benzene falls to 0,50 gallons per 1000 cubic feet, while the yield of unsaturated hydrocarbons increases. Ethylene so produced may be treated for the production of ethyl alcohol. Specifications 264,827, 309,455, 309,488, 324,939, and 342,319, [all in Class 2 (iii), Dyes &c.], are referred to. In the first Provisional Specification the space velocity most suitable for a maximum yield of ethylene and minimum carbon deposition is stated to be about double that necessary for maximum carbon deposition and about 1 1/2 times that for maximum yield of benzene, the initial material in each case being a methaneethane mixture. A multistage process is also described. The production of ethylene, acetylene, propylene, butylene, butadiene, and benzene is mentioned. The second Provisional Specification includes the treatment of unsaturated hydrocarbons e.g. ethylene and acetylene. This also refers to a multistage process.