METHOD OF THERMAL CRACKING FOR PRODUCTION OF PETROCHEMICALS FROM HYDROCARBON

PURPOSE:To decrease the yield of methane and, at the same time, to improve the yields of ethylene and propylene, by producing petrochemicals through thermal cracking of hydrocarbon in the presence of a high-temp. methane-contg. gas produced by making use of oxygen. CONSTITUTION:A starting hydrocarbon 1 is fed into a cracker 2. At the same time, a high-temp. methane-contg. gas 4 heated at 850 deg.C or above with oxygen 5 is fed into the cracker 2, where it is mixed with the starting hydrocarbon 1. After the completion of the thermal cracking, a reaction fluid 6 is fed into a quenching device 7 to quench it. The cooled reaction fluid 8 is fed into a separation-purification system 9, where it is separated into a cracked oil 10, an org. hydrocarbon 12, an olefin product 13, a fuel gas 14, a methane-contg. gas 15, etc. A part of the methane-contg. gas 15 is circulated into the cracker 2. This brings about an increase in the methyl radical concn., and the coupling effect thereof contributes to an improvement in the yield of ethylene.