A method for pressurizing a liquid exiting a phase separator includes opening an inlet control valve, thereby providing a two-phase fluid stream to a phase separator and producing a vapor stream and a liquid stream. Wherein a first liquid control valve prevents the liquid stream from leaving the phase separator. Then closing the inlet control valve and opening the first liquid control valve, thereby withdrawing the liquid stream from the phase separator and introducing the liquid stream into a lock hopper. Wherein, a second liquid control valve prevents the liquid stream from leaving the lock hopper. Then closing the first liquid control valve and then opening a pressurized vapor control valve, thereby providing a pressurized vapor stream to the lock hopper, thereby pressurizing the lock hopper. Then closing the pressurized vapor control valve, and opening the second liquid control valve, thereby withdrawing a pressurized liquid stream from the lock hopper.

A method for removing entrained liquid droplets from a gas is provided. The method includes introducing a gas with entrained liquid droplets into a cyclone separator, thereby producing a gaseous portion and a liquid portion. Wherein the gaseous portion exits the cyclone separator, and wherein the liquid portion is restricted by a liquid control valve and collected in a reservoir volume in the cyclone separator. The method also includes opening the liquid control valve upon receiving a signal from a liquid level sensor located in the reservoir volume, the liquid portion thereby exiting the cyclone separator.

A plant and a process for separating hydrogen from natural gas. The plant includes a hydrogen separation module, a heat exchanger, a decompressor, downstream of the heat exchanger and in fluid connection with the heat exchanger through a first outlet duct of the heat exchanger, and a flash separator, downstream of the decompressor and in fluid communication with the decompressor through an outlet duct of the decompressor. The flash separator separates a flow of natural gas with a hydrogen content higher than a predetermined threshold, entering the hydrogen separation module through an inlet duct of the heat exchanger, into a first flow of natural gas containing the excess hydrogen and a second flow of natural gas with a hydrogen content below the predetermined threshold. The flash separator includes an upper outlet and a lower outlet, from which an outlet or recirculation duct extends.

In a process in which ammonia is cracked to form a hydrogen gas product and an offgas comprising nitrogen gas, residual hydrogen gas and residual ammonia gas, residual ammonia is recovered from the offgas from the hydrogen recovery process by partial condensation and phase separation, and hydrogen is recovered from the resultant ammonia-lean offgas by partial condensation and phase separation. The recovered ammonia may be recycled the cracking process and the recovered hydrogen may be recycled to the hydrogen recovery process to improve hydrogen recovery from the cracked gas. Overall hydrogen recovery from the ammonia may thereby be increased to over 99%.

Processes and systems are provided for treating the tail gas stream of a sulfur recovery plant. The process comprising the steps of treating the compressed tail gas stream in a pre-treatment unit to remove the impurities; separating the dry stream in a first stage membrane unit, the first stage membrane unit comprises a membrane selective to carbon dioxide and hydrogen; reducing a temperature of the cryogenic feed in a cryogenic cooler to produce a cryogenic stream; separating the cryogenic feed in a knock-drum to produce a liquid carbon dioxide and membrane feed; separating the membrane feed in a second stage membrane unit to produce a rubbery membrane permeate and a rubbery membrane retentate, where the second stage membrane unit comprises a membrane selective to carbon dioxide over hydrogen; and treating the rubbery membrane retentate in a hydrogen recovery process to produce a hydrogen product stream and a carbon dioxide lean stream.

A method for separating hydrogen and nitrogen from a gas mixture, including a) thereby partially condensing a hydrogen and nitrogen gas mixture and producing a two-phase stream, b) phase separating the two-phase stream, producing a nitrogen-enriched liquid fraction and a hydrogen-enriched gaseous fraction, c) expanding the nitrogen-enriched liquid fraction, producing a lower-pressure nitrogen-enriched liquid or two-phase stream, d) adding heat to the lower-pressure nitrogen-enriched liquid stream, producing a warm nitrogen enriched gaseous stream, and e) adding heat to the hydrogen-enriched gaseous fraction, producing a hydrogen-rich product stream. Wherein, at least a portion of the heat added in step d) is removed in step a), at least a portion of the heat added in step e) is removed in step a), or at least a portion of the heat added in step d) and at least a portion of the heat added in step e) is removed in step a).