Seeking advice on HPF desulfurization of coke oven gas

After being treated with HPF (high-efficiency bag desulfurization), coke oven gas can usually have its hydrogen sulfide content reduced to low levels. Whether it can be reduced to below 50 ppm depends on the design of the desulfurization system, its operating conditions, and the concentration of hydrogen sulfide in the raw gas. Generally speaking, if the system is properly designed and well-maintained, it is possible to achieve stable control of hydrogen sulfide levels below 50 ppm. It is recommended to regularly check the system’s performance and make necessary adjustments and optimizations to ensure that the desulfurization effect meets the desired standards. .

Should we increase the circulation rate of the desulfurization liquid? We have already increased the circulation rate in our current system to its maximum level, but the effect is still not significant. Are there any other factors to consider?

This depends on factors such as capacity, hydrogen sulfide inlet volume, equipment compatibility, volatile ammonia levels, components of the desulfurization liquid, and the pump’s circulation rate

Our current gas flow rate is approximately 35,000–36,000 m³/h; the hydrogen sulfide concentration in the feed stream is about 7 g/m³. The ammonia vapor content in the desulfurization liquid is around 20 mg/m³, while the catalyst concentration is about 40 ppm. The content of by-products is around 300 mg/m³, and the suspended sulfur level is 1.0. The circulation rate of the desulfurization liquid is 850 m³/h, whereas the amount of air used for regeneration is 1,400 m³/h. There is another phenomenon: there is a temperature difference of 2–5°C between the gas inlet and outlet, with the inlet temperature being 24–26°C and the outlet temperature 28–30°C. However, the temperature of the desulfurization liquid in my reaction tank remains unchanged before and after the reaction, staying at around 30°C. Desulfurization is an exothermic process; the temperature of my desulfurization solution doesn’t increase. Have you encountered this phenomenon?

Currently, new enterprises are equipped with two desulfurization towers in operation and one as a backup, without any backup regeneration tower; they are designed for hydrogen sulfide levels of less than 20 mg/m3, which is fully achievable.

Considering the influencing factors at the source and during the reaction process, if the hydrogen sulfide content in the gas remains stable, for example around 4000 mg, the key lies in the reaction itself. One factor is the circulation volume – the circulation volume of the desulfurization liquid must be sufficient; in the case of a single stage setup, at least 3000 m3 is required per tower； The second is the alkalinity of the desulfurization solution, the suspended sulfur content, and the presence of by-products; in other words, it relates to the quality of the ammonia source used for ammonia evaporation and the effectiveness of desulfurization solution regeneration ； Third is the influence of reaction temperature, namely the gas temperature and the desulfurization liquid temperature

I saw in the documentation that both the gas temperature and the desulfurization liquid temperature should be between 2-5°C. Is this temperature difference appropriate?