Research on SCR flue gas denitrification and ammonia injection technology suitable for coal-fired boilers
In order to improve the denitrification efficiency of the SCR flue gas denitrification system for coal-fired boilers and reduce the denitrification cost,the acid washing method was used to regenerate the waste SCR catalyst from a coal-fired boiler denitrification system.The activity of the regenerated SCR catalyst was evaluated,and the ammonia injection rate of the SCR flue gas denitrification system for coal-fired boilers was optimized.The results show that when the sulfuric acid concentration is 0.6mol·L-1 and the pickling time is 30 minutes,the activity of the regenerated SCR catalyst is the best,and the denitrification efficiency can reach 88.6%,with a small difference compared to the denitrification efficiency of the fresh SCR catalyst.As the unit load gradually increases,the oxygen volume fraction at the outlet of the coal-fired boiler SCR denitrification system first decreases and then increases,and the reaction temperature gradually increases.However,the ammonia escape rate and ammonia injection amount both increase first,then decrease,and then increase again.When the unit load is 560MW,the operating efficiency of the target coal-fired boiler SCR flue gas denitrification system is relatively high,with an outlet oxygen volume fraction of 3.54%and an ammonia escape rate of 1.16×10-6,reaction temperature is 380℃,and ammonia injection amount is 96.46kg·h-1.The research results can provide a certain reference for improving the operational efficiency of the SCR flue gas denitrification system in coal-fired boilers.
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