Process and apparatus for thermal conversion of hydrocarbons to aliphatic hydrocarbons which are more unsaturated than the starting products, combining a steam cracking step and a pyrolysis step

摘要

A continuous pyrolysis and decoking process and apparatus is described for the production of acetylenic compounds, in which hydrocarbons and steam are circulated in at least one tube (31) of a steam cracking reactor (30) and steam is circulated in at least one tube (32) of that reactor. The hydrocarbon effluent and steam then circulate in at least one row (1) of a pyrolysis reactor (40) and the decoking effluent comprising steam circulate in at least one other row (2) of that reactor (4) to effect decoking. A set of valves V1, V2, V11, V12 is used to alternate the pyrolysis step path and the decoking step path. The temperature in the steam cracking furnaces is lower than that in the pyrolysis reactor.