Flue gas desulfurization and denitration in coke ovens

The semi-dry method is fairly acceptable. However, if the sulfur dioxide level in the flue gas is too high, then the issue of denitrification using ammonium bisulfate needs to be taken into consideration. Additionally, both the location for desulfurization and the surrounding environment must be considered. With the fully dry method, waste heat can be recovered first, followed by dry desulfurization and dust removal, before proceeding to the denitrification system. The sulfur content is very low, which reduces the impact on catalysts. No water is required throughout this process; the temperature drops by 20–30 degrees from the point of desulfurization to completion of denitrification. The downside is that the cost of desulfurization is high, and the effectiveness of this method varies – it’s advisable to gather more information within the industry.

First carry out denitration, then recover waste heat; you’ll cry when production is restricted. If the temperature for denitration is not high enough, increasing the amount of ammonia used instinctively can poison the catalyst. Things are still manageable if production isn’t restricted, but several coking plants have encountered problems with their high-temperature denitration systems after production restrictions were imposed. The only solutions are to replace the catalysts or add exhaust gas heating systems. After these changes, the volume of exhaust gas increases and there isn’t enough suction, forcing the fans to operate at higher speeds. It is recommended to take into account all possible factors that could affect operation before starting the project, otherwise there won’t even be a place to cry.

Okay, thank you. What method do you use?

There are two sets of fully dry-process systems: one involves denitrification first, followed by waste heat recovery, then desulfurization and dust removal. After the production capacity was restricted, the denitrification effect became much worse, and modifications are currently being planned. Another approach involves the recovery of waste heat from the station for use in desulfurization, dust removal, and denitrification. This scheme entails adding auxiliary lines at the inlet and outlet of the waste heat boiler; during periods of reduced production, it is possible to adjust the temperature of the fluid entering the subsequent processes, thereby ensuring their proper operation. The inlet temperature for dry desulfurization is around 220 degrees, and the desulfurizing agent used is sodium bicarbonate, which is costly.

Please leave your contact information so we can communicate easily

Can we have a conversation and learn from each other?*

Our system uses the rotary spray drying method (SDA) for desulfurization, as well as integrated dust and nitrogen oxide removal through thermal decomposition; it is accompanied by a fan unit, with emissions going through the original chimney. Currently, it is in a phase of reduced production, but its performance is still very good. Moreover, the operation is relatively simple, but this is possible only if the desulfurization process operates properly.

I’m not sure how your catalysts perform. In the semi-dry desulfurization process, it is usually carried out after denitration; otherwise, moisture can affect the lifespan of the catalysts. You’re doing things correctly by carrying out desulfurization first – if problems arise during this stage, it’s best to stop denitration to avoid affecting the catalytic surface area. There isn’t much contact involved in the semi-dry method. Personally, I prefer to carry out waste heat recovery first, followed by dry desulfurization and then denitration. However, the composition of flue gases from coke ovens is relatively complex, and the operating costs are high. Currently, the most stable solution is SDA+SCR. Many sintering plants now require desulfurization and denitration services, and they also favor the semi-dry method. But I’m still concerned about catalysts, as their cost is quite high. With temperatures of 400 degrees and high humidity, their lifespan is likely to fall short of expectations.