Problems of salt formation and blockage due to sulfuric acid concentration
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The sulfuric acid resulting from the nitration reaction needs to be evaporated and concentrated, from 72% to 93%, before it can be reused. However, sulfuric acid in the system corrodes the equipment pipes; metal ions are introduced into the sulfuric acid, and during the concentration process these metal ions precipitate as sulfates, thereby blocking the boilers and heat exchangers. The salts are mainly ferric sulfate; the iron ion content in sulfuric acid is about 100 ppm, while the content of other metals such as calcium and magnesium ions is less than 50 ppm. Do any of you have any good ways to solve the problem of salt buildup and blockages?
Well, more specifically? What method should be used for separation?
At present, 72% of the sulfate is in a dissolved state at 182°C before concentration, and 93% is dissolved at 40°C after concentration. It is only during the process of concentration and cooling that the solubility decreases, leading to precipitation. If filtration is to be used for separation, filters need to be installed during the concentration stage. But are there any effective filtering methods for sulfuric acid at high temperatures and high concentrations?
This post was last edited by pzhmotor on 2020-2-19 at 17:00. The problems faced in your manufacturing process are very similar to those we encounter when concentrating titanium dioxide waste acid; they are quite tricky and represent a significant challenge for us in this industry. (The poster can perform an internal search using the keywords ‘waste acid concentration’ and ‘scaling’) We use double-effect graphite heat exchangers for low-temperature concentration; currently, we are forced to lower the temperature by increasing negative pressure, as well as to carry out regular cleaning to maintain production. I have considered using ultrasonic online descaling to delay the scaling cycle, but this is difficult in tubular graphite heat exchangers (for metal heat exchangers, I would be willing to give it another try)…… As far as I know, the only method that has been tested on a pilot scale or put into practical use is filtering at the upstream stage, rather than filtering the intermediate products. Both membrane filtration and resin filtration are in use, but stability and cost present some issues at present.
A filtration tank is installed between the separator and the circulation pump. The sulfuric acid circulation fluid flows in from below and out from above; the slurry containing salts accumulated at the bottom is discharged to a filter press for filtration, and the filtrate is returned to the concentration system. You can give it a try.
There’s no good solution; just wash it. Who is the supplier of this device you have at home? Could you let me know?
The scaling of heat exchangers in the waste acid concentration process of titanium dioxide manufacturers results in low efficiency in waste acid concentration, thereby directly shortening the commissioning time of the plants. This is a major common challenge in the industry, one that has yet to see effective solutions. Our company’s new technology: strong acid scale inhibition dosing technology, which can effectively prevent scaling and solve this problem. For various types of scaling, such as carbonate, phosphate, sulfate, oxalate, silicate, and metal oxide scales, the problem of heat exchanger scaling in the waste acid concentration process is no longer a challenge! Interested in adding on WeChat: wm801128
The scaling of heat exchangers in the waste acid concentration process of titanium dioxide manufacturers results in low efficiency in waste acid concentration, thereby directly shortening the commissioning time of the plants. This is a major common challenge in the industry, one that has yet to see effective solutions. Our company’s new technology: strong acid scale inhibition dosing technology, which can effectively prevent scaling and solve this problem. For various types of scaling, such as carbonate, phosphate, sulfate, oxalate, silicate, and metal oxide scales, the problem of heat exchanger scaling in the waste acid concentration process is no longer a challenge! Interested in adding on WeChat: wm801128
Our company’s new technology: the strong acid scale inhibition dosing technology, which can effectively prevent scaling and solve this problem. For various types of scaling, such as carbonate, phosphate, sulfate, oxalate, silicate, and metal oxide scales, the problem of heat exchanger scaling in the waste acid concentration process is no longer a challenge! If you are interested, add me on WeChat: wm801128, phone: 13606362712