What is the reason why sulfur is not removed after wet flue gas desulfurization?
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Our facility has been in operation for nearly two years, and sulfur has not been removed in the wet flue gas desulfurization unit; the gas after desulfurization meets the process requirements, with a sulfur content of less than 20 MG/L. Could the problem lie in the desulfurization solution itself, or is it due to poor regeneration of the solution? Please provide your analysis!
It might be that regeneration was poor, and no sulfur foam was formed. The desulfurization liquid is turbid; be careful as this can cause blockages in the tower over time
It is likely that the amount of air being regenerated was too large, and the hydrogen sulfide level before desulfurization was also low, resulting in side reactions that led to the formation of by-products.
Two years already? It hasn’t been dealt with yet, I really admire the patience of your company’s management! Apart from the risk of tower blockage, the issues of high consumption and high waste liquid discharge have also been sources of constant concern and trouble.
It shouldn’t be 20 mg per liter; it should be per m³. As for the absence of sulfur production, there are many possible reasons – for example, improper mixing of the chemicals, insufficient regeneration pressure, low volume of air used for regeneration, short residence time in the regeneration tank, and so on. To determine the cause, it’s necessary to consider other parameters such as absorption temperature, sulfur capacity, sulfate content, residence time, volume of air used for regeneration, foam layer height, injector pressure, and so on
My brief opinion: 1. The sulfur content in the raw gas is too low. 2. Too much desulfurization liquid is entrained with the gas; a separator should be added after the desulfurization tower.
Impact of side reaction products on desulfurization ● The accumulation of by-products increases the viscosity of the desulfurization solution, affecting mass transfer and the formation of sulfur foam. ●The accumulation of by-products will precipitate out of the solution, disrupting normal operating conditions and increasing the resistance in the desulfurization tower; in severe cases, it can even block the tower and pipelines entirely, bringing production to a standstill. ●Soda ash (ammonia) consumption increases, but the washing efficiency of the desulfurization solution drops sharply, resulting in a decrease in desulfurization and sulfur recovery rates. ●High concentrations of (NH4)2SO4 and other by-products, or their precipitation, can also cause corrosion of carbon steel equipment. I believe that, based on the selection of more mature desulfurization agents, the main factor affecting the stability of the desulfurization system is the continuous increase in side reactions and their resulting by-products. No matter how carefully such reactions are controlled, they are still inevitable; what is referred to as stability is only short-term stability. The true solution lies in completely eliminating the amount of by-products generated by these inevitable side reactions! The desulfurization solution can be subjected to crude salt (mixed salt) extraction, and the desalted desulfurization solution can be reused. This not only addresses the issue of increased by-products, keeping the content of by-products in the desulfurization solution stable, but also generates economic benefits. Low investment, small land footprint, easy operation – it completely solves the problems of environmental protection and low desulfurization efficiency. Other methods are neither thorough nor free of negative effects; they only provide temporary solutions rather than addressing the root cause. Speak up if you have something to say! My email address is: zhp1389@126.com
Hello! Firstly, the conditions you provided are inaccurate; based on my understanding, the possible reasons are: 1. The total sulfur content in the feed gas is low. 2. The filtration of suspended sulfur is poor. 3. Sulfur ointment applied to the tower.