Pyrolysis and oxidative pyrolysis of chloromethane in steam

Abstract

The chlorine-catalyzed oxidative pyrolysis (CCOP) process was recently developed as a method to convert methane, the major component in natural gas, into more valuable products such as ethylene, acetylene, and vinyl chloride. The CCOP process involves the initial chlorination of methane into CH[sub 3]Cl, followed by the oxidative pyrolysis of CH[sub 3]Cl into higher molecular products. Pyrolysis and oxidative pyrolysis of CH[sub 3]Cl into high molecular weight products such as C[sub 2]H[sub 2] and C[sub 2]H[sub 4] has been studied in a flow reactor in the presence of steam as diluent. The effects of feed composition, in particular the CH[sub 4] and O[sub 2] levels, residence time, and temperature on CH[sub 3]Cl conversion and C[sub 2] selectivities have been investigated. The presence of small amounts of oxygen in the feed inhibited the formation of carbonaceous deposit such as soot, tar, and coke without decreasing C[sub 2] selectivities. It was possible to generate product streams with C[sub 2] concentrations in excess of 45 mol % (C[sub 2]H[sub 2] + C[sub 2]H[sub 4] + C[sub 2]H[sub 3]Cl) following the removal of steam, HCl, and unreacted CH[sub 3]Cl, at C[sub 2] product yields in the range 25-30%.