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This post was last edited by Steven_p0kTk on 2023-8-14 09:00. Wet desulfurization is a chemical absorption desulfurization method widely used in China’s gas purification industry; it typically involves using ammonia water or soda ash as absorbents, along with catalysts, to absorb hydrogen sulfide from gases. In the regeneration system, the catalyst is restored to its active state through regeneration; at the same time, the absorbed divalent sulfur, or the sulfur that has been converted into elemental sulfur, is accelerated in its oxidation process under the action of oxygen and the catalyst. The sulfur then agglomerates and grows, precipitating out, and under the influence of a large amount of air it floats to the surface, thereby allowing the catalyst to be restored to its active state while the sulfur is discharged as foam. The sulfur foam is then processed using a filter press or a sulfur melting tank to further separate sulfur from the desulfurization liquid, thereby obtaining sulfur of relatively high quality and recovering the desulfurization liquid. In actual production, there are issues with regeneration and sulfur foam treatment, which cause sulfur to adhere to the fillers, increase the resistance in the desulfurization tower, and even lead to blockages in the tower, severely affecting the normal operation of the enterprise. Hazards of tower blockage in wet flue gas desulfurization: 1. Tower blockage increases the system resistance, leading to higher energy consumption in the chemical production ventilation system. At the same time, operating at high resistance poses significant safety risks. 2. Tower blockage inevitably leads to uneven distribution of the desulfurization liquid, affecting the gas-liquid contact surface and reducing the system’s desulfurization efficiency, which results in an increased hydrogen sulfide level downstream of the tower or even levels that exceed the specified limits. 3. Tower blockage inevitably leads to an increase in the gas velocity; as a result, the desulfurization liquid can easily be carried out of the system, resulting in greater losses of catalysts, ammonia water, alkalis, and other auxiliary materials. 4. It increases the workload on workers; clearing the tower takes at least ten days, and the process involves high safety risks. Reasons for increased tower resistance during wet flue gas desulfurization operation and preventive measures: 1. Insufficient purity of the gas – improper control of process parameters in earlier stages leads to an increase in the content of coal dust, tar, naphthalene, and other substances in the gas. These substances cannot be completely removed through sulfur foam flotation; if this situation persists, such impurities accumulate within the desulfurization system, causing tower blockages. Furthermore, since sulfur is an oil-soluble substance, the accumulation of large amounts of tar in the desulfurization system causes the tar and sulfur to mix and agglomerate, which affects the normal flotation of sulfur, leads to an increase in suspended sulfur, and results in its attachment to the packing, thereby exacerbating tower blockage. 2. The amount of by-products in the desulfurization system increases, and when this accumulation reaches a high level, a sudden drop in system temperature can lead to the excessive precipitation of these by-products, causing salt crystallizations to block the towers in the desulfurization system. 3. Due to poor control of the desulfurization regeneration system, the regeneration effect of the desulfurization solution was unsatisfactory. A significant amount of sulfur in the solution failed to be floated out; instead, it was carried into the desulfurization tower along with the solution and deposited in the packing, gradually leading to blockage of the tower. 4. The spraying density of the desulfurization liquid is insufficient; since some sulfur is also precipitated within the desulfurization tower while hydrogen sulfide is being absorbed, a low spraying density can cause dry areas to form on the filler in the tower, leading to uneven flow and ultimately tower blockage. Especially for towers with a larger diameter, it is essential to ensure an adequate amount of circulating fluid, in strict accordance with the design requirements. 5. The solution distribution nozzles at the top of the desulfurization tower are clogged, resulting in uneven distribution of the solution; this is similar to a situation where the spraying density is insufficient, and dry areas tend to form on the packing. 6. There are problems with the design of the desulfurization tower or regeneration tower, or with the equipment structure itself; for example, improper selection of packing, unreasonable structure or installation of the liquid distributors and redispersers in the tower, or clogged nozzles ； The tray structure of the regeneration tower, the type of level controller, and other such factors can easily lead to misdistribution of the solution or the accumulation of sulfur in the distribution troughs, thereby causing blockages in the tower. It is necessary to promptly analyze the causes of tower blockage and take targeted measures. It is preferable to address the issue before the tower pressure increases and blockage occurs, so as to avoid situations where the tower has to be shut down for maintenance, which is labor- and time-consuming.