METHOD FOR CONCENTRATING H2S FROM GAS CONTAINING H2S AND CO2 AT HIGH CONCENTRATION

摘要

PURPOSE:To obtain a gas contg. CO2 at a low ratio and contg. H2S at a high concn. by passing the gas contg. H2S and CO2 at high concns. through an absorption column contg. an aq. soln. of sodium carbonate or potassium carbonate as a liquid absorbent. CONSTITUTION:The gas contg. H2S and CO2 at high concns is passed through the absorption column contg. the aq. soln. of 3-8wt.% sodium carbonate or potassium carbonate adjusted to 10-50 deg.C as the liquid absorbent for 2-12sec gas-air contact time, by which H2S is selectively absorbed in the above- mentioned liquid absorbent. The absorptivity of H2S does not increase so much and the increase ratio of the absorption capacity of CO2 increases when the concn. of the sodium carbonate or potassium carbonate exceeds 8wt.%. Such concn. is, therefore, undesirable. The absorption capacity of H2S decreases and a large volume of the liquid absorbent is required if the concn. is below 3wt.%. Such concn. is, therefore, undesirable. The absorptivity of CO2 increases sharply and the selective absorbency of H2S is poor if the liquid temp. exceeds 50 deg.C. The absorption of H2S is insufficient if the liquid temp. is below 10 deg.C. Such temp. are, therefore, undesirable.