REMOVAL OF ACID GASES FROM HOT GAS MIXTURES

摘要

A process for removing acid gases such as CO2 and H2S from gas streams using an aqueous alkaline scrubbing solution which is circulated between an absorption and regeneration stage wherein the stripping steam for regeneration is derived at least partly from the hot feed gas to be purified. The thermal efficiency of the process is substantially improved by first heatexchanging the hot feed gas with the scrubbing solution to raise stripping steam and then heat-exchanging the hot feed gas with water (which is preferably condensate water produced in the scrubbing process) in a second heat exchanger operating under reduced pressure, thus recovering additional lowlevel heat from the feed gas and producing low-pressure steam which is compressed and then utilized as additional stripping steam. In a preferred embodiment, additional low-pressure steam is generated by also flashing off low-pressure steam from the regenerated scrubbing solution and compressing this steam together with the steam produced in the second heat exchanger for use as stripping steam.