Engineering system for removing NOx from flue gas in low temperature at rear end of desulfurizing tower

Abstract

The invention relates to a system for removing NOx from kiln flue gas under the environment of high humidity (approximate to saturated humidity) and state approximate to normal temperature (40-60 DEG C) state. The system is used for efficiently removing NOx from flue gas with high temperature lower than 60 DEG C after calcium desulfurization, dual-alkali desulfurization and the like, so that SO2 and NOx in the flue gas can be fundamentally separated and absorbed to generate corresponding sulfates and nitrates, and most parts of particulate substances and Hg can be removed. The invention relates to a system for purifying flue gas by means of oxidizing NO in the flue gas through compressed air along the axial flow direction of a flue at the rear end of the existing flue gas desulfurizing tower to generate NO2 and NOx which are absorbed by an absorbent (water, ammonia water, alkali liquor and the like) under the special catalyst condition (low temperature and high humidity). The system provided by the invention can be widely applied to denitrating transformation of the existing desulfurization system.

Description

technical field [0001] The invention relates to the field of environmental protection, in particular to a technical system for purifying flue gas. Background technique [0002] Most of the large and medium-sized kilns in China have completed desulfurization transformation since the Eleventh Five-Year Plan period. If the SCR method is used to remove NO x It is necessary to renovate the boiler and install it before the desulfurization tower, which will easily cause a large amount of reconstruction and damage to the desulfurization tower. However, if it is used after the desulfurization tower, the flue gas will have a large amount of moisture in a high-humidity environment after spraying and desulfurization, and the flue gas temperature will be about 50 ~60°C is lower. Contents of the invention [0003] In order to overcome the existing defects and constraints, use cheap compressed air to oxidize under low-temperature catalyst conditions, and at the same time use the absorpt...

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Problems solved by technology

[0002] Most of the large and medium-sized kilns in China have completed desulfurization transformation since the Eleventh Five-Year Plan period. If the SCR method is used to remove NO x It is necessary to renovate the boiler and install it before the desulfurization tower, which will easily cause a large amount of reconstruction and damage to the desulfurization tower. However, if it is used after the desulfurization tower, the flue gas will have a large amount of moisture in a high-humidity environment after spraying and desulfurization, and the flue gas temperature will be about 50 ~60℃ lower

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