High resistance in the drying tower
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In a 100,000-ton pyrite-based acid production plant, there is an abnormal resistance in the drying tower. The pressure at the outlet of the electrostatic demister is -5 kPa, while the pressure at the inlet of the fan is -11 kPa. The total resistance across the entire drying tower amounts to 6–7 kPa. It is suspected that the wire mesh demister may be clogged; however, replacing it with a new one did not resolve the issue. It is a floor-mounted drying tower, with acid stored at its bottom. Ceramic corrugated structured packing was installed in July 2017, and the tower is supported by spherical arches, so it shouldn’t clog so quickly. The flow rate of acid through the drying tower is around 230 m³/h, and a tubular acid distributor is used. Please help figure out what could be the problem
This post was last edited by springflower on 2018-1-26 23:10. A higher pressure drop means greater resistance to gas flow. So it can be divided into several aspects: the circulating area decreases. Is there broken filler filling the gaps in the newly filled material? What is the porosity of the new filler? What is the voltage drop when first starting the vehicle? Another issue is an excessive amount of circulating acid; check whether absorption requirements are met and adjust the amount of circulating acid accordingly.
Choose a filler with good clogging resistance, such as a grid.
I thought about it, and it’s possible that when the packing was replaced, there was a problem with the leveling layer of the spherical arch; perhaps the size of that leveling layer was too small, which blocked the gaps in the spherical arch.
Was the pressure drop across the drying tower measured after replacing the packing before restarting the operation? And were any measures taken to prevent broken filler during replacement? Based on what you’ve described, it is preliminarily judged that the broken packing has blocked the gaps in the regular packing.
What is the dust value in the purification indicators? Is the spherical arch leveled using small fillers?
The purified gas does have a somewhat high level of mineral dust, and the dome was also leveled using 76mm rectangular saddle rings. . .
This post was last edited by in the blink of an eye on 2018-1-27 at 19:39. The porosity of the spherical arch is already low; by using small fillers to level it, the porosity between the spherical arch and the filler layer becomes even lower.
If everything else has been ruled out, stop the machine and check whether the flue pipe from the electric demister to the dryer tower is blocked. The porosity of neatly packed packing is higher than that of loosely piled packing, resulting in lower tower resistance. Is there a problem with the pressure gauge? What are the effects of high system resistance on the device’s production capacity and conversion temperature?
We are also facing a relatively high pressure drop in the drying tower right now. As beginners, we would appreciate it if experts could analyze the reasons behind this, so that it can be useful in our work. Thank you.
It is recommended to use a water column to measure the resistance of the main packing and the mesh in the drying tower separately. It is not recommended to rely on the data from on-site pressure gauges (due to large errors).