How to deal with high pressure difference in the desulfurization tower? ? ?

It can be flushed by increasing the amount of desulfurization liquid and adjusting the gas flow rate； To analyze the reasons for the increase in resistance, appropriate actions should be taken based on the specific circumstances

This post was last edited by 654262293 on 2010-9-11 at 12:51: 1. Enhance regeneration and strictly control the suspended sulfur content in the solution. 2. Take advantage of the parking time to clean the desulfurization tower packing with clean water. 3. If the blockage is severe and the lifting method is not effective, it is necessary to carry out the task of removing the filler. 4. The 888 desulfurization method is used; this method has the effect of removing sulfur, though it requires the replacement of the desulfurizing agent. You can contact Changchun Dongshi; they have extensive expertise in this area.

The main reason for the increased resistance in the desulfurization tower is poor regeneration, which leads to the formation of excessive by-products. The solutions adopted are to increase the amount of desulfurization liquid (not for too long), or to shut down the system and remove the packing for cleaning. In daily management, it is necessary to strengthen the operational control of desulfurization solution regeneration.

It’s difficult to determine where the problem lies based on the information provided by the poster. The poster can share details about how the system is operating as well as the composition of the solution, so that everyone can analyze it. It’s best to be in a situation where resistance is on the rise during this period.

Analysis of the reasons for high pressure difference in the desulfurization tower: (1) Blockage by mechanical impurities: soot and suspended particles. High downtime of the electrostatic precipitator is caused by instrument failures, process issues, and overly dirty corona electrodes. The circulating water in the semi-water gas system is dirty, as is the desulfurization solution, which results in more impurities in the gas; this can be seen from the 4M16 piston. (2) Sulfur blockage: Fine sulfur particles (suspended sulfur) and sticky sulfur; these are the main causes of blockage, accounting for 78% according to the analysis data. A. It is unreasonable to shake off a large amount of liquid when extracting by-products. When the concentration of the by-product from this plant is high, excessive dumping and replenishment methods are employed, which makes it difficult to float the sulfur foam; the suspended sulfur level can reach as high as 19 g/L, and this situation may last from one or two days to as long as nine days. When removing the blockage, it looks like tree rings, layer by layer. B. Effect of operating temperature. When the ambient temperature is 0°C, the temperature inside the desulfurization tower is around 15°C, while it is about 22°C in the oxidation tank. At high pH levels and low vanadium concentrations, the rate of sulfur oxidation decreases, and the formation of sulfur bubbles becomes unstable. Low temperatures, on the other hand, facilitate the dissolution of suspended sulfur in the solution as well as the formation of Sx; as a result, it is harder for sulfur bubbles to form, and blockages are more likely to occur. Additionally, at low temperatures, the viscosity of the solution increases, causing blockages to propagate from bottom to top. C. Improper replenishment of liquid after sulfur melting; when the ambient temperature is high, the amount of liquid added has little effect on the foam. When the climate is cold and the temperature of the liquid being added is too low, as well as when the amount of liquid added is large, the foam disappears quickly, and it becomes difficult to float sulfur in the solution. (3) Salt blockage: Based on the analysis data of blockages in the upper tower, salt blockage cannot be ignored either. A. Since the desulfurization reaction mechanism is relatively complex, it will be discussed from a macroscopic perspective. The accumulation of intermediate products, by-products, and other soluble salts in the solution makes it easy for NaHCO3 and NaCO3, which have lower solubility, as well as NaCNS, which is present in the highest concentration, to precipitate out. B. The solubility is lower at lower temperatures; therefore, substances such as Na2SO4, Na2S2O3, NaHCO3, NaCO3, and NaCNS tend to precipitate. C. Impact of equipment mismatch: The empty tower velocity of Tower No. 2 is too low; an empty tower velocity of 0.32 m/s is sufficient to meet the requirements for desulfurization efficiency, but this is only half of the standard value of 0.6–0.8 m/s. With low air velocity and poor liquid-phase turbulence, the diffusion and transfer of Sx are inadequate, resulting in poor regeneration efficiency in the tower. Furthermore, since the absorption of H2S is primarily controlled by the gas film, a low space velocity and a long gas-liquid contact time facilitate the reaction between CO2 in semi-water gas and the alkali solution to form NaHCO3. The literature suggests that the contact time should not exceed 30 seconds. Tests show that approximately 11%–12% of the CO2 is absorbed within the tower, and the longer residence time of the solution in Tower 2 results in a higher concentration of salts in that tower. D. Effects of improper alkalization methods: Practice has shown that when the total alkalinity in the solution cannot be increased, the solution is already at saturation. At this point, resorting to sudden addition of alkali to ensure desulfurization efficiency not only causes large fluctuations in pH levels, but also slows down the oxidation rate due to the high pH value, reduces the selectivity for the formation of elemental sulfur, and makes it difficult to recycle by-products. Additionally, high concentrations of alkaline solutions cause salts to precipitate directly on the surface of the packing material. During normal production, alkali should be added, but it is not advisable to complete the addition in about half an hour. (4) Salt-sulfur blockage: This mainly occurs in the middle part of the tower, especially at lower temperatures. Intermediate products, by-products, soluble salts, and semi-water gas can easily lead to salt-sulfur blockage when H2S is absorbed, due to the presence of oxygen; this happens particularly when the liquid-to-gas ratio is not adjusted properly. 3. Prevention and countermeasures for desulfurization tower blockage A. When the ambient temperature is low, steam is added to the semi-water gas entering the tower to maintain the temperature of the gas entering the tower at around 40°C. When the temperature of the solution does not reach 35°C, a temporary heater is used to keep the solution temperature between 35°C and 40°C, thereby increasing the solubility of the solution and reducing its viscosity. B. When the NaCNS concentration reaches 230 g/L, a small amount of the solution should be gradually removed, and then an appropriate amount of fresh alkaline solution should be added. The liquid from the sulfur melting tank should be added gradually to the oxidation tank; any excess should be stored in a storage tank. When the concentration of NaCNS exceeds 200 g/L, the liquid from the sulfur melting tank is fed into the reaction tank for the extraction of by-products using NaCNS. So that the sulfur foam can be floated out, reducing the suspended S in the solution. C. Control the alkalinity appropriately and improve the feeding method. The prepared raw materials should be added to the system in small amounts, at regular intervals, and in a balanced manner. When clogging occurs, it is not advisable to add alkali abruptly; instead, some of the solution containing high levels of by-products in the system should first be removed, and then alkali should be added as appropriate. D. Ensure even air distribution in the air ducts; the rotation speed must not be lower than 550 revolutions to prevent the foam from disappearing, thus ensuring stable overflow and maintaining the system’s regeneration efficiency. E. Ensure the spray density of the desulfurization tower packing. Pay attention to the degree of turbulence inside the tower and adjust the liquid-to-gas ratio properly. F. Operate the electrostatic precipitator properly to remove impurities from the circulating water in the gas generation system, ensuring the purity of semi-water gas. G. Control the components of the solution carefully, as ADA generates H2O2 using 8505 during the regeneration process, which accelerates the occurrence of side reactions, increases alkali consumption, causes by-products to accumulate in the solution, and shortens the lifespan of the solution. H. The clear liquid sedimentation tank after sulfur melting should be cleaned frequently to prevent excessive amounts of mature sulfur from entering the system.

Reply to 3# 654262293: Thank you all for your advice; we will take it into consideration

Reply to 1# lzw299: The most fundamental solution is: 1. On the hardware side, replace the packed absorption tower with a swirl plate absorption tower. 2. Control the regeneration of the solution, that is, maintain a low level of suspended sulfur. 3. Control the amount of by-products in the solution; if the level of by-products is high, the only solution is to replace part of the solution. In short, if, as mentioned above, your absorption tower is a packed tower, it is likely that the solution itself is causing blockages in the tower; therefore, it is recommended that you switch to a cyclone plate absorption tower.

Reply to 1# lzw299: The poster is from Luxi, right? It is recommended to analyze the composition of the liquid to determine whether it is a sulfur blockage or a salt blockage, before deciding on how to deal with it. SY7 should be a good catalyst; I’ve also used Changchun Sanyuan before and it worked well. One should be cautious about replacing the desulfurization agent – sometimes, if the reasons for the problem aren’t properly analyzed, replacing the catalyst not only fails to solve the issue but can also cause additional problems.

Reply to 9# Chemical gas purification: Thank you. We will consider it carefully and also go to other manufacturers to learn from them*.

In general, desulfurization units experience an increase in resistance after one and a half years of operation; it is crucial to determine the cause of this issue. Salt buildup is a possibility, but sulfur buildup is likely the main factor. If nothing else works, disassembling the unit will reveal that sulfur buildup is indeed the problem