Investigation on Formation Characteristics of Aerosol Particles during Wet Ammonia Desulfurization Process

An experimental research was carried out on formation characteristics of aerosol particles during the Wet Flue Gas Desulfurization (WFGD) process with different ammonia-based desulfurizers. Three desulfurizers of aqueous ammonia, ammonium sulfate, and ammonium sulfite were compared and influences of desulfurization operating conditions were investigated. The results revealed that numerous aerosol particles were produced during the desulfurization process for all three desulfurizers. In terms of the quantity of aerosol particles produced, the aqueous ammonia and ammonium sulfite took the first and second place, respectively. Ammonium sulfate produced the least aerosol particles, with submicron sizes for most cases. For all three desulfurizers, the production rate of aerosol particles increased with increasing liquid-to-gas ratio, pH value as well as the desulfurization liquid temperature; a higher concentration of SO2 in the flue gas resulted in more aerosol particles being generated at a lower pH value of the desulfurization liquid, while an opposite effect was realized for the situation with a higher pH value; a small amount of SO3 in the flue gas intensified the formation of aerosol particles, and with its increase the number concentration of aerosols increased continuously. Optimum operating conditions for WFGD process were finally achieved, which are 50 degrees C of the desulfurization liquid temperature, 10% of the mass concentration of the desulfurizing agent, 10-15 L/Nm(3) of the liquid-to-gas ratio, 11, 7.0, and 8.0 of pH value for aqueous ammonia, ammonium sulfate, and ammonium sulfite, respectively.