Our plant uses two-stage absorption for sulfuric acid exhaust gases, but the effect is not very good
Thread Content
Our plant uses two-stage absorption for sulfuric acid exhaust gas, but the results are not very good. How is it with other companies in this industry? How many stages of absorption are there, what is the ammonia ratio, and do alkalinity and density need to be monitored in real time?
Our factory originally used a one-turn one-suction system, with the exhaust gas being absorbed in one stage using lime slurry, achieving an absorption rate of over 70%. But the scaling is severe. Later, a two-turn two-suction configuration was adopted, resulting in an average exhaust gas concentration of 200–300 ppm. If conditions permit, it is recommended to use a two-turn two-suction process. Converting it to sulfuric acid is a bit more economical.
At both extremes, it’s possible that your conversion rate isn’t up to standard, or that the catalyst’s performance is poor
Our company uses the amino acid method to absorb sulfuric acid exhaust gases to produce liquid sulfur dioxide. It turns out that similar problems existed as well; mainly, the absorption efficiency of the primary foam tower declined. Last year, modifications were carried out, and a new foam tower was designed and manufactured, using modified PP material which is easy to work with. After the modification, with the alkalinity of the first-stage concentrated recycle mother liquor controlled at 0.6–0.9 mol/L and its specific gravity controlled at 1.240–1.260, and the alkalinity of the second-stage dilute recycle mother liquor controlled at 0.4–0.5 mol/L and its specific gravity controlled at 1.05–1.10, the absorption efficiency of the entire absorption system can be maintained at over 92%, while the emission concentration of sulfur dioxide can be kept below 1000 mg/m3. In terms of testing, specific gravity is measured online, while alkalinity is analyzed by taking samples every hour.
Can 4# hnzcz further reduce the sulfur dioxide emission concentration by increasing the alkalinity of the circulating liquid mentioned above? What is the method for analyzing the alkalinity of the concentrated circulating mother liquor?