Flue gas desulfurization and denitrification system

Abstract

The invention discloses a flue gas desulfurization and denitrification system. The system comprises a coal-fired boiler, an SCR (selective catalytic reduction) reactor, a dust remover, an absorption tower and a chimney which are sequentially connected through a flue gas pipeline, wherein a combustion chamber of the coal-fired boiler is connected with a denitrification reducing agent jet module, and a denitrification catalyst layer is arranged in the SCR reactor; an alkali liquor inlet and an alkali liquor outlet are arranged at the lower part of the bottom of the absorption tower, the alkali liquor outlet is communicated with a feeding port of a lime water reactor and a spray system at the top of the feeding port respectively, a discharging port of the lime water reactor is connected with the alkali liquor inlet, the system further comprises a slaked lime charging mechanism connected with the feeding port of the lime water reactor and a caustic soda supply device connected with the alkali liquor inlet, the upper part of the lime water reactor is cylindrical, the diameter of the lower part decreases gradually, a stirring paddle is arranged in the upper part of the lime water reactor, and a filter net is detachably arranged at the lower part. The equipment is low in one-time investment and energy consumption, and the desulfurization and denitrification efficiency is higher than 95%.

Description

technical field [0001] The invention belongs to the field of environmental protection, in particular to a flue gas desulfurization and denitrification system. Background technique [0002] At present, the flue gas of existing industrial boilers will produce sulfur and nitrogen oxides, which are the main substances of air pollution, seriously destroying the ecological environment and endangering human health. [0003] The existing flue gas denitrification methods mainly include: flue gas denitrification selective catalytic reduction method (abbreviated as SCR), selective non-catalytic reduction method (abbreviated as SNCR), low-nitrogen combustion, etc., among which SNCR and low-nitrogen combustion denitration efficiency High, it is impossible to achieve deep removal of nitrogen oxides. Although SCR has the advantages of mature and reliable process and high denitrification efficiency, it can stably control nitrogen oxides at 70mg / Nm3 in the early stage of catalyst operation u...

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Problems solved by technology

[0002] At present, the flue gas of existing industrial boilers will produce sulfur and nitrogen oxides, which are the main substances of air pollution, seriously destroying the ecological environment and endangering human health.

[0003] The existing flue gas denitrification methods mainly include: flue gas denitrification selective catalytic reduction method (abbreviated as SCR), selective non-catalytic reduction method (abbreviated as SNCR), low-nitrogen combustion, etc., among which SNCR and low-nitrogen combustion denitration efficiency High, it is impossible to achieve deep removal of nitrogen oxides. Although SCR has the advantages of mature and reliable process and high denitrification efficiency, it can stably control nitrogen oxides at 70mg/Nm3 in the early stage of catalyst operation under the condition that ammonia escape does not exceed the standard. , even close to 60mg/Nm3

However, to achieve the goal of less than 50mg/Nm3, it is necessary to increase the amount of catalyst and reducing agent used, and the increase in the amount of catalyst used will increase the concentration of SO3 at the flue gas outlet, and the increase in the amount of reducing agent injected will cause ammonia gas to escape. Both will lead to clogging of the air preheater; on the other hand, it will also increase the cost and energy consumption of denitrification

[0004] The main methods of flue gas denitrification are: acid method, alkali method, limest

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