Talk about the operation of the mixed acid mixer in the dry absorption process
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The mixed acid mixer used in the early stages of production at our factory: the water supply pipe is made of SS902 alloy along with a PTFE-based water distributor, while the casing is made of steel lined with PTFE； The water supply pipe and the PTFE-based water distributor are connected using alloy bolts; after some time, the water distributor came loose, which caused damage to the filter screen at the inlet of the first suction pump, blockage of the small pipes in the acid separation tank, loss of the fluorinated lining on the casing of the acid mixer, and corrosion of the steel pipes. The rear water inlet pipe is now made of pure PTFE material, with the surrounding area reinforced using stainless steel bolts coated with PTFE. The sleeve remains made of steel with a PTFE coating, but the thickness of this PTFE layer has been increased ； After about a year of use, part of the fluorine-coated layer on the outer sleeve has peeled off, and most of the inner steel tube has corroded ； The water inlet pipe is in slightly better condition; it has cracks at the bottom, and the PTFE-coated bolts that provide reinforcement around it have corroded, leaving only the outer PTFE layer intact. Note: In the first absorption cycle, the amount of water added is high and the acid temperature is high (above 90 degrees), resulting in severe damage to the acid mixer; in the second absorption cycle, less water is added, so the degree of damage is slightly lower. The suction and discharge cycles are connected by pipes; I would appreciate any advice or experience shared by experts.
The fluorine-lined pipe manufacturing process is also crucial; thickness alone isn’t sufficient – what matters is the quality of the adhesion between the lining layer and the steel pipe. It is recommended to use a process that resists negative pressure for lining pipes.
Just use a thick-walled PTFE tube!
The elbow connecting the acid return pipe to the circulating acid tank has been replaced with a special-shaped tee, into which a PTFE tube is inserted; water and acid are mixed together and then poured into the tank, which ensures uniform mixing. The tank lid is less prone to corrosion. The only drawback is that the cast-iron pipe inserted into the tank needs to be replaced frequently – every two or three months perhaps – but the advantages outweigh the disadvantages
Use a high-silicon alloy; it’s more convenient, though the price is slightly higher.