The impact of the pH value of circulating slurry on a wet flue-gas desulfuration process

In a limestone-gypsum wet desulfuration system the pH value of circulating slurry is an important parameter that affects the performance of the desulfuration system. By using a parallel-flow orderly falling-film type wet desulfuration device, an experimental study was performed of the impact of the pH value of the circulating slurry on a limestone-gypsum wet desulfuration process. The experimental results indicate that a higher pH value of the circulating slurry will contribute to a higher desulfuration rate. However, the content of limestone in the slurry will undergo an increase accordingly. When the pH value of the slurry in the circulating channel is greater than 6.0, the content of limestone in the slurry will rise drastically. If the above pH value is less than 4.8, however, the desulfuration rate will markedly drop. Summing up the effect of the pH value of the circulating slurry on desulfuration rate and limestone content, one can conclude that the rational pH value of the slurry in the circulating channel should range from 4.8 to 6.0.