Katalytisches Kohlenwasserstoffkrackverfahren

A hydrocarbon feedstock is cracked in reactor 2. Used catalyst is sent to a regenerator 4 in which coke deposits on the catalysed are oxidised in the presence of the gas mixture comprising oxygen and inert gas (e.g. CO2). Regenerated catalyst is returned to the reactor 2. A cracked hydrocarbon product stream flows to a fractionating column 6. An overhead stream from the fractionating column 6 is cooled so as to form a liquid-vapour mixture. Downstream of phase separation in an accumulator 10, a stream of the vapour phase ("wet gas") has methane and hydrogen separated therefrom by pressure swing adsorption in plant 8. Higher hydrocarbons than methane are adsorbed in the plant 8 and on regeneration of the adsorbent form a desorbed gas fraction which is sent to an upstream wet gas compressor 12 and from there to a downstream wet gas compressor 16. A compressed wet gas stream is sent from the downstream wet gas compressor 16 to further hydrocarbon processing units (not shown). The feed to the PSA plant 8 may be taken from upstream of the compressor 12 or from intermediate the compressors 12 and 16, or from both locations. Throughput of hydrocarbon feedstock through the cracking plant is able to increased.