Features and application considerations of structured packing
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This post was last edited by in the blink of an eye on 2024-5-11 at 14:58. Structured packing can handle low liquid-to-gas ratios, typically with high operating gas velocities, provided that its dew point density is high. The standard acid-point density for sulfuric acid dry absorption towers is 43 points/m2, but the requirement for structured packing is much higher than this. Therefore, for the structured packing channels with a acid drop rate of 43 points/m2, the amount of acid sprayed is too high, which can easily lead to flooding and a significant increase in mist entrainment; S-shaped packing performs better under such conditions. For areas with a coverage of 43 points/m2, the lack of acid spraying can easily lead to a deterioration in the mass transfer performance of the dry absorber. This is equivalent to uneven conditions of drought and flooding: on one hand, the amount of acid mist generated inside the tower increases sharply, while on the other hand, the mass transfer parameters of the tower deteriorate, such as excessive moisture levels and a decrease in the SO3 absorption rate. It is noted that replacing the packing in a dry absorption tower with regular packing usually poses no major problems; the main issue lies in the relatively large packing height of dry absorption towers designed traditionally. For new dry absorption towers with a limited height of the main packing, it is recommended to add a randomly piled packing transition layer, which essentially increases the density of acid separation points.
The characteristic of structured packing is its ability to maintain good gas-liquid distribution and high mass transfer efficiency even at high operating gas velocities. However, structured packing requires a higher droplet density of the base fluid, meaning there are more liquid droplets in contact with the gas per unit area. Precautions for application include: when using structured packing, it is necessary to ensure an adequate density of acid drop points in order to avoid local flooding and the formation of foam ； For traditional dry absorption towers with a large packing height in the design, replacing the regular packing is relatively easy ； For new dry absorption towers with a limited height of the main packing, it is recommended to add a randomly piled packing transition layer in order to increase the density of acid separation points and improve the gas-liquid contact conditions. .
For the distributed packing in the two absorption towers and the tubular acid separator, if regular packing is replaced, is it best to replace the acid separator at the same time?
Could someone who has good knowledge of the use of regular sulfuric acid packing please offer some guidance?:D
The new device design uses structured packing; great care must be taken regarding the height of this packing. Since the droplet density in the existing acid separator is insufficient, using loose packing to achieve secondary distribution of the liquid can yield good results. In the absence of such a loose packing layer, structured packing still has the ability to distribute the liquid on its own, by sacrificing some layers of packing in order to ensure comprehensive coverage of liquid distribution. As a result, the height of the structured packing used for actual absorption becomes insufficient. This causes the absorption conditions in the three towers to deteriorate.
After 2/3 of the structured packing is placed inside the tower, random-packed packing is added as a transition layer to increase the density of acid separation points and improve the gas-liquid contact conditions.
The original tubular acid separator can be retained, but the height of the transitional bulk packing must be sufficient, and a small portion should also be reserved for acid mist capture in order to reduce the load on downstream systems. Since we know it’s because the droplet density of the acid distributor is insufficient, buy another one. Request from the manufacturer that 80 points be provided, or ask them how many points they can create; go for the maximum number possible