Analysis of the operating procedures for the dry absorption unit in acid waste regeneration systems

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I. Job Tasks 1: The purified furnace gas, after dust removal and temperature reduction, has its moisture removed in a drying tower before it proceeds to the conversion stage. 2. The converted SO3 gas is absorbed by 98% acid in the absorption tower to produce the product. The exhaust gases are passed through an exhaust gas absorption tower, where the remaining SO2 and SO3 are absorbed using a 10% sodium hydroxide solution, before being released into the atmosphere. II. The process flow is shown in the process flow diagram of the dry absorption section with control points. The purified furnace gas is sprayed with 93% acid in a drying tower to reduce the moisture content to below 0.1 grams per standard cubic meter; thereafter, acid foam and mist are removed using a fiber mist eliminator, and the gas is then sent to the conversion section via a blower. The heat generated in the drying tower and the absorption tower is carried away by their respective circulating acids, and the heat is removed using cooling water in their respective concentrated acid heat exchangers. To maintain balance in the acid concentration within each tower’s circulation system, 93% of the acid produced in the drying tower is fed to the absorption tower, while 98% of the acid from the absorption tower is returned to the drying tower, thereby ensuring balance between acid concentration and water levels in the drying tower’s circulation system. The absorption tower produces acid with a purity of 98%, which is sent to an underground tank; from there, acid pumps transfer it to the tank for finished acid. The gas exiting the absorption tower enters the exhaust gas absorption tower, where 10% sodium hydroxide solution is used to absorb the SO2 and SO3 contained in it. The exhaust gas after absorption is then released through a chimney. III. Operating Parameters 1. Temperature: (1) Inlet temperature of the drying tower: ~40°C; inlet acid temperature: ≤50°C. (2) Inlet temperature of the absorption tower: ~160°C; inlet acid temperature: ≤55°C. (3) Inlet gas temperature of the exhaust gas absorption tower: ~65°C. 2. Concentrations: Acid concentration in the drying tower is 92.5–93.5%, while the acid concentration in the absorption tower is 98.3–98.6%; sodium hydroxide concentration in the exhaust gas absorption tower is ~10%. 3. Spraying density: It is ≤25 m3/m2·h in both the dry absorption tower and the similar units. 4. The desiccant absorption index indicates the moisture content of the gas in the drying tower