Annealing furnace flue gas SCR denitrification solution

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Annealing process is a very important part of the continuous hot-dip galvanising production line. The quality of annealing and redox of the steel strip can directly affect the mechanical properties such as strength, toughness and elongation of the product as well as the effective temperature to be achieved for galvanising, so the combustion control of the annealing furnace is particularly important. At the same time, the high temperature exhaust gas from hot-dip galvanising furnaces contains a large amount of NOx fumes, which can cause pollution and harm to the atmosphere, so it is also necessary to implement denitrification projects for the exhaust gas generated during hot-dip galvanising production.

The SCR denitrification process is a process in which ammonia, liquid ammonia or urea solution is used as a reducing agent under the action of a catalyst to "selectively" react with NOx in the exhaust gas and produce non-toxic and non-polluting NOX and H2O, and is widely used. Hebei Hanlan SCR denitrification system is a mature and reliable technology with many successful applications in seven regions of China. According to the actual condition of the annealing furnace flue gas, the technical staff carried out many on-site visits, testing and technical communication with professional flue gas analysis instruments, and developed and designed the Wanchun annealing furnace flue gas denitrification system solution. After the denitrification of the annealing furnace, the solution is able to meet the more stringent emission requirements, i.e. the NOx emission concentration of the hot plating production line is reduced from 200-300 mg/m3 to below 50 mg/m3.

For the annealing furnace flue gas denitrification system system, Hebei Hanlan adopts SCR selective reduction denitrification technology to purify the NOX in the annealing furnace flue gas. As the summary flue gas temperature is 220°C, a low temperature denitrification catalyst suitable for this flue gas temperature condition is selected. The denitrification catalyst is characterised by high air velocity, high activity, high mesh count, wide temperature window and reduced equipment footprint. At the same time, due to the targeted design, the influence of relevant factors in the flue gas is fully considered, so that the catalyst can adapt to fluctuations in the equipment operation under various working conditions and can achieve good results, clearing the last barrier on the environmental protection pathway for the customer.