Hydrogen purification for make-up gas in hydroprocessing processes

摘要

The recycle gas stream containing hydrogen that is part of the feedstream to a hydroprocessing reactor is mixed with the low purity make-up hydrogen and the sour flash gases upstream of the recycle gas compressor and compressed by the recycle gas compressor. The compressed gases pass through a methane and higher (C1+) absorber to produce a sweet hydrogen recycle gas stream that is delivered to the hydroprocessing reactor at 96-98 mol % hydrogen. The process can be used to advantage in existing process facilities to increase the hydrogen partial pressure in the feedstream to the hydroprocessor where the existing recycle gas compressor is not designed for compressing the high purity hydrogen.

主权项

1. A process for hydrogenating a feedstream in a hydroprocessing reactor, the feedstream comprising a heavy hydrocarbon liquid component, the reactor also receiving a hydrogen gas input component, the reactor producing a reactor effluent, the process comprising:
a. separating the reactor effluent with a high pressure separator into an effluent liquid stream and an effluent gas stream, the effluent gas stream comprising unreacted hydrogen, methane and heavier hydrocarbons; b. compressing the effluent gas stream from the high pressure separator and a make-up hydrogen gas stream in a recycle gas compressor to produce a compressed recycle gas stream containing unreacted hydrogen, methane and heavier hydrocarbons from the effluent gas stream, and make-up hydrogen from the make-up hydrogen gas stream; c. cooling the compressed recycle gas stream to a temperature in the range of +30° F. (−1.1° C.) to −40° F. (−40° C.); d. contacting the cooled compressed recycle gas stream with a lean liquid solvent stream comprising C4 to C5 hydrocarbon components in an absorption zone to absorb the methane and heavier hydrocarbons from the compressed recycle gas stream to produce a hydrogen-rich gas stream containing 90 to 99 mol% hydrogen and a rich liquid solvent stream; e. recovering the hydrogen-rich gas stream from the absorption zone; f. adding the hydrogen-rich gas stream to the hydroprocessing reactor feedstream as the hydrogen gas input component; and g. flashing the rich liquid solvent stream in at least one flashing stage to produce the lean liquid solvent stream comprising C4 to C5 hydrocarbon components for contacting the cooled compressed recycle gas stream in step (d), and to produce a methane and heavier hydrocarbons gas product stream.