Hydrogen sulfide (H2S), carbon dioxide (CO2), COS and RSH removal from natural gas or syngas by physical absorption. Bulk-acid gas removal with simple flash regeneration. Removes impurities to pipeline specification with additional thermal regeneration step. Highly selective H2S removal, even at high CO2 partial-pressures. Simultaneous dehydration and BTEX removal.
For bulk acid gas removal the Morphysorb process simply requires solvent flash regeneration as the acid gas compounds are physically dissolved. Applications vary from product gas specifications of several percent for the acidic components down to about 2% for CO2 alone. Additional thermal regeneration is required for H2S removal down to pipeline specification (4 ppmv H2S, 2% CO2) or removal of CO2 to liquefied natural gas (LNG) specification (50 ppmv CO2, 4 ppmv H2S).
The process flow diagram shows a bulk-acid gas removal unit as an example. The feed gas enters the absorber bottom, flows upward through a packed bed, where it is treated with the regenerated solvent, and leaves the absorber at the top.
The enriched solvent exits the absorber bottom and is flashed consecutively into the recycle flash drums. The offgas from these drums is recycled to the absorber feed by a two-stage compressor minimizing methane losses. The solvent is further flashed into the acid gas flash drums for regeneration. The acid gas is produced at two pressure levels for high-pressure downhole reinjection or for further processing in a sulfur recovery unit. The regenerated Morphysorb solvent is pumped back to the absorber.
Due to the solvent’s specific nature (low co-absorption of C1 to C3 hydrocarbons, high acid gas capacity, non-corrosive, low-vapor pressure and non-toxic) the process exhibits the following features: low recycle gas flow and higher hydrocarbon product yield, low solvent circulation rate, extensive carbon steel usage as construction material and low solvent losses in the product and acid gas.
Operating conditions: Typical feed conditions range from 400 psi to 1,300 psi with a 5% to 70% acid gas content (CO2 and H2S). Depending on the process application, product specifications vary from a few ppmv to several percent for bulk removal.
Licensor: Uhde GmbH, Dortmund, Germany