Cryogenic separation process of streams containing hydrogen methane, C3, C4, or C3/C4 hydrocarbons

摘要

Low temperature separation of a stream of hydrogen (H2), methane (CH4) and hydrocarbons with 3 and/or 4 carbon (C) atoms, previously subjected to dehydrogenation, involves cooling the dehydrogenation stream rich in 3-4 C hydrocarbon to low temperature by mixing it with (part of) the H2 separated and discharging a stream rich in 3-4 C hydrocarbon from the separation process. The novel features are as follows. Cooling and partial condensation of the stream of H2, CH4 and 3-4 C hydrocarbons and warming and vaporisation of the dehydrogenation stream rich in 3-4 C hydrocarbons, mixed with (part of) the H2, is carried out in a single heat exchanger with only one other (process) stream concerned in the heat exchange between these 2 streams. The other (process) stream is a liquid side stream rich in 3-4 C hydrocarbons obtained from low temperature separation.