Temperature of circulating acid in the drying tower and absorption tower.

In the new system, the parent acid used for production is purchased as a ready-made 98% acid, which is then filled into the circulation tank. After cooling, the temperature of the circulating acid is generally kept below 50 degrees. As for the temperature of the finished acid, it depends on where acid production takes place within the system: if it occurs in the lower sections of the circulation pipeline, the acid temperature will be higher; if it occurs in the upper sections of those pipelines, the temperature will be lower. Generally, no special efforts are made to control the temperature of the finished acid

Before starting operation, the acid temperature in the drying tower must be raised to 60°C through heating; the acid temperature in the circulation tank of the absorption tower is 65°C. 93% and 98% acid can be used directly. Once production becomes stable, the acid temperatures after absorption and drying reach 70°C and 75°C respectively. The acid circulating in the absorption tower reaches 80°C after cooling. The acid temperature of the finished product coming out of the drying tower’s circulation tank must be kept below 50°C after passing through the acid cooler. Additionally, the acid temperature at the outlet of the finished product cooler, as well as in the carbon steel storage tanks, should be kept below 50°C, while it should be below 60°C in stainless steel tanks.

After passing through the acid cooler in the drying process, the acid temperature should generally not exceed 65; it should not exceed 80 for the first and second absorption stages, and it should not exceed 40 for the finished product. In the drying tower, the acid temperature is best kept below 60, as higher temperatures can easily lead to excessive moisture content

According to the design requirements for our dry acid absorbers, the temperature of the acid entering these devices should not exceed 60 degrees; therefore, the temperature of the acid entering our tower is kept below 50 degrees. The design requirements for single-stage acid absorbers state that the temperature of the acid in such devices should not exceed 95 degrees, so the temperature of the acid entering the tower in this case is kept below 75 degrees.

This post was last edited by pengshujie on 2010-9-28 at 23:25. Our plant uses a 2-turn 2-suction process for sulfur-based acid production; we are providing some parameters below in the hope it will be helpful. The temperature of the acid entering the drying tower is 75–80 °C, and the acid concentration is 98.5%； The temperature of the acid exiting the drying tower increases by slightly 2–4°C, and the acid concentration drops to 98.3. The acid temperature in the absorption tower is 75–80 °C, and the acid concentration is 98.5% ； The temperature of the acid exiting the absorption tower rises to around 100°C due to the heat of absorption and dilution; the acid concentration is adjusted to 98.5% by adding water at the bottom of the tower. The acid temperature entering the secondary absorption tower is 75–80 °C, with an acid concentration of 98.5% ； The temperature of the acid exiting the second absorption tower rises to around 90°C due to the heat of absorption and dilution; the acid concentration is adjusted to 98.5% by adding water at the bottom of the tower. The acid from the first absorption tower and the second absorption tower is cooled to 75–80 °C by a cooler.

Reply to 6# pengshujie: The guy on the 6th floor must have typed by mistake. The dry acid temperature can’t be that high; if it were, the purification equipment would have stopped working long ago. The dry adsorption balance couldn’t possibly hold up either, right? :P

Reply to 6# pengshujie: Why is the concentration of the acid used for drying and absorption in your factory the same? Also, what is the reason for such a high temperature of the acid in the drying tower? If a higher temperature in the absorption section is understandable, then I don’t understand why this happens during drying. Please provide an explanation!

Reply to 8# yusmile: Thank you for the extra points. In our plant, the circulating acid used in the drying tower and the first absorption tower follows an 8-shaped circulation pattern. 98.5% of the acid at the bottom of the first absorption tower is sent to the drying tower after cooling; 98.3% of the acid at the bottom of the drying tower is pumped – part of it going back to the first absorption tower and the rest being exported as finished acid. It should also be noted that there are several methods for circulating acid in the dry cleaning section, with slight differences among them. As for the temperature issue you mentioned, the acid at the bottom of the absorption tower is around 100°C, and at 80°C, the water vapor pressure of 98.3% sulfuric acid in the gas phase is 0.00016 KPa. The requirements for air drying are