Composition and method for removing nitrogen oxides in desulfurizing tower

Abstract

The invention relates to a composite denitrfying agent and a method for removing nitrogen oxides from purified flue gas, and in particular relates to a method for forming a mixture with limestone slurry in a desulfurizing tower, desulfurizing the limestone slurry and removing the nitrogen oxides in the composition. The composition is formed by desulfurizing and denitrifying 0.5 to 5 weight parts of denitrfying agent and 100 weight parts of aqueous solution of limestone slurry in the desulfurizing tower, wherein the denitrfying agent consists of a catalyst which accounts for 1.7 to 2.3 weight percent of the denitrfying agent, 10 to 20 percent of oxidant and 78.3 to 87.7 percent of ion solvent; and the denitrfying agent has the pH value of 6 to 8. The composition is injected into the desulfurizing tower through a circulating water injection port or a process water injection port and is in countercurrent contact with the flue gas in the desulfurizing tower for removing the nitrogen oxides. The method can be used for thermal power plants and various combustion boilers which take petroleum and oil as fuel and comprise the desulfurizing tower device, and is used for removing the nitrogen oxides in the flue gas, and 90 percent of emission pollution is reduced. The method has obvious substantive effects.

Description

[technical field] [0001] The invention relates to a composition and a method for purifying nitrogen oxides in flue gas, in particular to a composition and a method for removing nitrogen oxides in a desulfurization tower. [Background technique] [0002] The nitrogen oxides in the tail gas emissions after the combustion of fossil raw materials undergo photosynthesis in the atmosphere to form phosgene pollution, the main component of phosgene is nitrogen oxides. Environmental protection is becoming more and more important and urgent. The nitrogen oxides emitted by boiler combustion account for 70% of the total emissions. Reducing the emission of nitrogen oxides is an important means to improve the environment and the greatest benefit for human beings to improve living conditions. [0003] The currently used denitrification method is solid ammonia selective catalytic reduction (SCR). This technical requirement is to design a denitrification system at the outlet of the boiler fl...

AI Technical Summary

Problems solved by technology

To achieve the purpose of removing nitrogen oxides, the technical disadvantages are that the solid catalyst is easy to deactivate, the flue gas flow will seriously erode the catalyst, ammonia leakage will cause secondary pollution, and it will corrode the equipment at the rear of the flue.

The catalyst of this method is easy to deactivate, and when the temperature is low, it will form a cohesive liquid - ammonium bisulfate (NH 4 HSO 4 ), the catalyst is severely eroded, and the reaction decreases linearly.

[0006] (2) Selective non-catalytic reduction method (SNCR): This method does not use a catalyst, but consumes a lot of ammonia and urea

And the requirements for reaction temperature and residence time are very high, it is difficult to master

[0007] From the above denitrification technology methods, whether the technology of method 1 is suitable for China's national conditions is because the coal used in developed countries is clean coal, while my country uses raw coal (non-clean coal), and it is obvious that the catalyst is easy to deactivate and consumes a lot of catalyst. , Recycling technology is still under study and cannot meet the requirements of emission standards

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