Kind folks who can help, please solve a problem in actual production. Thank you so much
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We are a benzoic acid slicing device. In the diagram, the gas-phase washing tower of the slicer is shown; a sodium hydroxide alkaline solution is used, with the pH level maintained around 11, in order to wash away the benzoic acid powder and acidic gases present in the drum-type slicer. The gas flow is driven by a fan. This shows the structure at the bottom of the tower; it consists of a large tank similar to a horizontal container, with large blind covers sealing both ends. The melting point of benzoic acid is 122 degrees Celsius, and the benzoic acid that is drawn in gradually forms a scale layer in the middle of this tank – only an opening the size of a fist remains for air to pass through. The washing liquid flows downward and is discharged through the outlet, without coming into contact with this scaled layer, which can lead to blockages in the gas phase of the slicer. Powder accumulates inside the drum, and as more powder builds up, it can cause blockages in the discharge valves and other components. There is also a strong unpleasant odor. The workshop has proposed a solution, as shown in the diagram below, and opinions from everyone are being sought. This represents the gas-phase pipelines; the pipeline in the middle is for low-pressure steam. This opening also gets blocked over time, and the steam cannot remove the blocking substances. This is the solution provided by the management, and now I would like to seek the opinions of experts to see where improvements are needed or if there are any better ways to address this issue. My idea is: 1. Add internal coiled tube heating inside, and wrap insulation around the outside, or add external heating to help dissolve the scaling substances; 2. Install a distributor after the liquid flows down from the bottom of the tower, so that the entire interior can be washed by the liquid; 3. Set up a separate washing line to flush that wall from the side. Just like p-1003 in the figure, I’m asking for help from experts. Thank you so much!
I didn’t quite understand the manufacturing process; this is just my personal opinion for reference: There are deposits at the bottom of the alkali washing tower, which cause scaling and blockages. What’s needed is an effective waste discharge system to reduce the saturation level of the waste salts. (There is likely no regeneration device; the effectiveness of removing acidic gases cannot be assessed solely based on pH. It is necessary to reduce the amount of waste salts in the solution, drain it promptly, and replenish the alkali solution in a timely manner.) ) Usually, the bottom of the tower is a cylinder, and this horizontal structure inherently has dead zones; even in the absence of dust, salt will precipitate and cause scaling once its concentration reaches saturation. In the renovation plan, it’s likely that only the “level output” feature will be useful. Adding heat tracing could backfire, as the scale becomes harder after concentration. Without making major changes, I might try to make a few holes at the bottom of the tub to allow for drainage, thereby reducing dead zones; I could also use larger pipes connected to quick-release valves for regular drainage. To prevent air leakage, a liquid seal is attached to the outlet. The safest approach is to change the horizontal cylinder to a structure with vertical side walls, make the bottom drain pipe thicker, and carry out regular drainage in addition to overflow drainage. (The scrubber towers in gas stations and boiler rooms, as well as those in desulfurization and dust removal systems, all have this structure.) The twin vertical pipes at the gas station, with the bottom part also shaped conically)
Thank you for your reply. It’s due to the dead corners that the cleaning solution cannot reach those areas; over time, a scale layer forms and blocks the gas phase. Draining the liquid and replenishing the alkali solution are standard procedures. Now we are considering adding a liquid seal at the bottom as well as using purge steam. Thanks for your response
Melting point: 122.13 °C, boiling point: 249.2 °C, relative density (15/4 °C): 1.2659. It appears as white needle-like or scale-like crystals. It sublimes at temperatures above 100 ℃. Slightly soluble in cold water and hexane; soluble in hot water, ethanol, ether, chloroform, benzene, carbon disulfide, and turpentine. The content description is a bit confusing to read. It is speculated that the blockage is caused by a blockage in the gas line between the process equipment and the spray tower. The process medium, benzoic acid, is a solid, and blockages occur due to sedimentation and adhesive sticking. The principle for resolution lies in the flow channel: use a single device to collect particles as much as possible without creating resistance. The collected materials can be cleaned relatively easily