SO3 removal rate and emission test of the limestone-gypsum wet desulfurization system for coal-fired power plants

Abstract

This paper studies the SO3 removal ability of dual tower wet desulfurization (in series) and adopts a combination of on-site flue gas sampling and laboratory condensation control. A dual tower (series) supported boiler is used. The SO3 content in the original and clean flue gas of the dual cycle wet desulfurization device was measured, and the removal rate of SO3 of the device was measured. Desulfurization is calculated on the basis of the influence of unit electrical load, coal sulfur content, and desulfurization (raw material flue gas) inlet particle concentration on removal rate. This paper discusses and analyzes the SO3 and SO3 emission concentrations for SO3 removal rules in desulfurization systems. The results indicate that the total sulfur content of coal is relatively high, and the concentration of SO3 is relatively high. The traditional flue gas and net flue gas content in the dual tower wet desulfurization system (series) is relatively high. When burning sulfur-containing coal, there may be “blue smoke” in the flue gas. When the unit load changes between 182 MW and 350 MW, the SO3 removal rate of dual tower wet desulfurization (in series) is between 46.7% and 65.3%, with a net flue gas SO3 concentration of 16.0 mg/m3∼20.5 mg/m3. Due to equipment layout and other reasons, the SO3 removal rate of the primary tower is lower than that of the secondary tower. The removal rate of SO3 is also affected by the concentration of original smoke particles. Due to the condensation of SO3 on the particles and the dust removal of the adsorption tower, the higher the concentration of raw flue gas particles is, the higher the removal rate is. SO3 will be higher. The study also suggests the SO3 removal ability of double tower (series) and double ring wet desulfurization, which is better adapted to changes in load and coal. The next step is to explore the SO3 removal capacity of the dual tower system by optimizing its operating parameters. In addition, due to the arrangement of a desulfurization system after dust removal, it is impossible to control the SO3 source. Subsequent research can control the production of existing SO3 through coal distribution and combustion control.