Natural gas purificn. before chlorination to chloromethane cpds. - by simultaneous desulphurisation, methanisation and cracking over two catalysts in single-zone reactor

摘要

In the prodn. of chloromethanes (I), esp. highly pure MeCl and CH2Cl2, from natural gas (II) by thermal chlorination of CH4, (II) contg. max. 3% N2 is purified in a sinzle-zone reactor contg. a hydrogenation catalyst (III) for residual desulphurisation and a cracking/hydrogenation catalyst (IV) for simultaneously converting CO2 to CH4 and craking the 2+ C hydrocarbons. (III) and (IV) are sepd. only by a layer of expanded metal. Gas mixt. of H2 and (II) in 1:(10-20) vol. ratio is passed through (III) and (IV), heated to the operating temp. Purified gas is subjected to thermal chlorination conventionally, then washed with water, dried, compressed and cooled to ca.- 20 deg. C. Uncondensed prods. are recycled or removed and (I) are distilled. Active components of (III) are pref. hydrogenated and bound CuO, MoO3 and ZnO; and of (IV) NiO and Pd and/or Al2O3 and/or Ni and/or Cr2O3. Desulphurisation, hydrogenative cracking and methanisation of CO2 are carried out at 200-1000 kPa, 3202-430 deg. C and a throughput of 500-3000 v/vh. ADVANTAGE - (II) is purified by a simple, economical process, so the overall process is more economical.