Process for increasing the hydrogen purity and recovery in dehydrogenation

A process for recovering hydrogen from a dehydrogenated effluent stream comprising:

• separating the dehydrogenated effluent stream, in a separator, to produce a separator overhead stream comprising hydrogen and a separator bottom stream comprising dehydrogenated product;
• compressing the separator overhead stream in a hydrogen compressor section to produce a compressed stream;
• cooling the compressed stream in a vapor economizer by heat exchange with a discharge drum overhead stream to produce a cooled compressed stream;
• chilling the cooled compressed stream in a chiller to produce a chilled stream;
• and
• separating the chilled stream in a discharge drum to produce the discharge drum overhead stream comprising a hydrogen product stream.

A process for recovering hydrogen comprising:

• compressing a net gas stream together with a tail gas recycle stream in a hydrogen compressor section to produce a compressed stream;
• recovering hydrogen from the compressed stream in a pressure swing adsorption (PSA) unit to produce a hydrogen product stream and the tail gas recycle stream;
• and
• completely recycling the tail gas recycle stream to the hydrogen compressor section.