An experimental study for H₂S and CO₂ removal via caustic scrubbing system

In this study, removal of hydrogen sulfide (H₂S) and carbon dioxide (CO₂) from simulated syngas has been studied on one column scrubbing system. Gas flow rate as a measure of gas residence time and superficial gas velocity, gas composition, inlet H₂S load, flow modes (countercurrent and cocurrent) and packing geometry were the parameters in the design and/or operation of an acid gas scrubber system. Better H₂S scrubbing efficiencies have been obtained in countercurrent flow mode than that of cocurrent flow mode. When accordingly designed, static mixer with its superior performance on H₂S removal overweighed to structured packings. The coexistence of CO₂and H₂S has been shown to increase the sodium hydroxide (NaOH) consumption along the scrubber column thereby decreasing the H₂S removal efficiency at higher H₂S loads. The gas residence time as changing with the gas velocity was found to be more dominant on acid gas removal efficiency than the effect of superficial gas velocity within the experimented range. A gas residence times of equal or above 3 s were seemed to be closer to the optimum point.