GB659616A - Process for the oxidative cracking of non-aromatic hydrocarbons - Google Patents

Abstract

659,616. Cracking gaseous mixtures. UNIVERSAL OIL PRODUCTS CO. Jan 24, 1949, No. 1857. Convention date, March 30, 1948. Drawings to Specification. [Class 55(ii)] ] To produce a gas suitable for distribution in city mains from propane, butane, and similar liquified petroleum gases containing at least two carbon atoms per molecule, separate streams of the gas and air or other gas containing over 20 per cent of oxygen by volume are heated to between 540‹ and 870 ‹C and intimately mixed in the proportion by weight of 10-35 of oxygen to 100 parts hydrocarbon, then discharged into a reaction zone in which partial combustion of part of the fuel provides heat for cracking a greater part to form hydrogen, methane, ethylene &c. the product gases being cooled by heat exchange with the incoming gas streams. The heat exchanger may be of alloy steel tubular construction, the mixing chamber of metal or refractory material and the insulated reaction zone of iron-free refractory with or without baffles or packing but maintaining a high degree of turbulence. Other heat transfer means such as checker work traversed alternately by the reaction products and the feed streams, moving beds of pebbles &c. or fluids such as steam may replace the tubular exchanger if adequate to yield a combustion efficiency, i.e. the ratio of heat absorbed by the cracking reactions to that generated by combustion, of at least 50 per cent. With a preheat temperature of 650‹-760‹C the reaction zone temperature reaches 870‹-1040‹C about “-1/3 of the length of the reaction zone from the mixer and rapidly falls to 700‹-820‹C at the entrance of the heat exchanger. The mixer may be less than 3 per cent of the reaction zone volume: pressures up to about 3.5 atmospheres may be employed and the residence time in the reaction zone of the order of .05 seconds. A mixture obtained in one example by a 97.8 per cent conversion of propane comprises H2 12.3, CH, 15.4, C2 H4 14.3 CO 9.0, CO, 2.4, N, 42.2 per cent. A graph and table correlating experimental data relating to a range of mixtures obtained from propane enable product gas density and calorific value to be ascertained corresponding to various ratios of oxygen in the feed stream and to combustion efficiencies. Specification 637,108 is referred to.