It is possible to use the main fractionator overhead accumulator as the degassing drum. You are correct in saying any dissolved gasses in the sour water will evolve at the lower pressure and become a recycle through the wet gas compressor and the primary absorber in the gas plant. This flashed gas flow rate is much smaller than the total wet gas flow, so I think the impact on amine degradation and corrosion will be small. As you know, a change like this should go through a Management of Change process that includes a process hazards review. The capability to route sour water from the overhead accumulator to the Sulfur Plant needs to be adequate for this increased water rate to prevent refluxing water back to the main fractionator.
