Why are wire mesh foam catchers not used in the absorption towers of large and medium-sized acid production plants these days?

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This post was last edited by mkp369 on 2018-5-27 06:19. I remember that when I started working in 1995, a sulfuric acid plant with an annual production capacity of 30,000 tons was considered to be of medium size. It is now **explicitly stipulated that acid production plants with an annual capacity of less than 300,000 tons are not allowed to be put into operation. In earlier designs, wire mesh or F46 mesh foam catchers were commonly used in the first and second suction towers. Currently, in China’s sulfuric acid industry, fiber-bed cylindrical mist eliminators are used for both the first and second absorption towers in large and medium-sized acid production plants. Why are fiber mist eliminators required for the first absorption tower and the second absorption tower these days? This is because before the 1990s, China’s sulfuric acid plants were imported from the former Soviet Union. The empty tower gas velocity in the sulfuric acid dry scrubber was low, the packing height was high, and the flue gas concentration was not high. At that time, fiber bed mist eliminators were not yet the standard solution; metal wire meshes or F46 wire meshes could barely suffice for use in such systems. With the rapid advancement in the trend toward larger-scale acid production facilities in China’s sulfuric acid industry, the largest single-unit acid production facility currently in use is the 4800 MTPD acid production plant that utilizes copper smelting flue gas at the Zhongyuan Gold Smelting Plant. In large and medium-sized acid production plants, the gas velocity in the dry absorption tower can reach 2 m/s, while the height of the packing is only about 3 meters. As a result, the amount of mist generated within the dry absorption tower is much higher compared to traditional designs. In addition to using a distributor with 43 points per m2, a fiber-bed cylindrical demister is also necessary to control the amount of acid mist at the outlet of the dry absorption tower. Since the drying tower mainly contains acid foam, a wire mesh foam catcher is still sufficient to meet the requirements. There are fewer and fewer absorption towers equipped with wire mesh foam catchers. Not long ago, I visited a smelting and acid production plant; the original design called for wire mesh foam catchers to be used in the absorption towers. Since there was a lot of acid carried downstream, these have now been replaced with fiber bed cylindrical mist eliminators.