888 Wet Flue Gas Desulfurization Temperature Control

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During operation, the temperature of the desulfurization liquid should not be too high. Generally, the temperature should be maintained between 38-42°C; if it exceeds 45°C, the bubbles tend to break easily, and the flotation of elemental sulfur is not effective. If the temperature of the gas entering the tower is too high (above 50°C), it will inevitably reduce the solubility of H2S and O2 in the alkaline solution, thereby lowering the purity of the gas. At the same time, this affects the oxygen absorption and activation of the catalyst, resulting in an increased requirement for catalyst usage. On the other hand, if the temperature of the gas entering the tower is too high, the temperature of the desulfurization liquid rises as well, which facilitates the formation of by-products salts and hinders the flotation of elemental sulfur. In general, the total amount of the three minor salts (Na2S2O3, Na2SO4, and NaCNS) should be less than 250 g/L; in particular, the concentration of Na2SO4 in the solution is preferably not exceeding 40 g/L. When the amount of by-products increases, measures should be taken promptly (by discharging or removing some of the desulfurization liquid to lower its temperature and induce crystal formation). Otherwise, the excessive amount of by-products in the desulfurization solution tends to crystallize within the tower and adhere to the packing; over time, this leads to salt blockages.