Wet-method low-temperature denitration system

Abstract

The invention discloses a wet-method low-temperature denitration system, which belongs to the technical field of flue gas treatment. The wet-method low-temperature denitration system comprises a condenser, a pulse bag-type dust collector, a 1 # fan, a wet-method desulfurization purification tower, a wet-method low-temperature denitration purification tower and a chimney which are sequentially connected through pipelines; wherein the condenser is used for cooling flue gas, the pulse bag-type dust collector is used for purifying and dedusting the flue gas, and the purified and dedusted flue gasis introduced into the wet-method desulphurization purification tower under the transmission of the 1 # fan; wherein a gas outlet of the wet-method desulphurization purification tower is connected with a gas inlet of the wet-method low-temperature denitration purification tower, a gas outlet of the wet-method low-temperature denitration purification tower is connected with the chimney, and the chimney is used for discharging flue gas purified through denitration treatment. The wet-method low-temperature denitration system has the advantages of high desorption efficiency, small occupied area, low operation cost and the like.

Description

technical field [0001] The invention relates to the technical field of flue gas treatment, more specifically, it relates to a wet low-temperature denitrification system. Background technique [0002] At present, the mainstream flue gas denitrification technologies in the market are mainly two denitrification methods: SNCR (in-furnace denitrification) and SCR (outside furnace denitrification); the denitrification agents are mainly urea and ammonia water. [0003] For SNCR (furnace denitrification), the desorption temperature is limited between 850°C and 1200°C. The denitrification agents are mainly urea and ammonia water. The desorption efficiency of urea is generally about 60%. The urea solution is cracked at a high temperature above 600°C to form In the process of denitrification by oxidation-reduction reaction of ammonia gas, the highest desorption efficiency will not exceed 75%; the desorption efficiency of ammonia water is relatively high, and the direct reduction desorp...

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Problems solved by technology

[0003] For SNCR (furnace denitrification), the desorption temperature is limited between 850°C and 1200°C. The denitrification agents are mainly urea and ammonia water. The desorption efficiency of urea is generally about 60%. The urea solution is cracked at a high temperature above 600°C to form In the process of denitrification by oxidation-reduction reaction of ammonia gas, the highest desorption efficiency will not exceed 75%; the desorption efficiency of ammonia water is relatively high, and the direct reduction desorption at a temperature above 850°C is generally above 75%, and the highest is not more than 85% %; If the temperature in the furnace is too low, denitrification cannot be performed as low as 850°C, the amount of denitrification agent is too high, and ammonia escape exceeds the standard, which will also cause environmental pollution and other environmental problems

At present, there is a denitrification method in the market—activated polymer ammonia denitrification method, the desorption temperature is between 600°C-850°C, and the desorption efficiency is between 85%-95%, which fully meets the needs of environmental protection, but it is still limited by the temperature in the furnace. ; Especially industrial boilers and industrial kilns, there are many types, and the production process requirements are special. Some industrial kilns do not allow wet spray denitrification at all. Wet denitrification will directly affect the quality of production process products. An intelligent control denitrification process of dry spraying urea + catalyst in the furnace, but the desorption efficiency can only be between 50% and 65%. Compared with the current environmental protection requirements and the unique characteristics of the industrial boiler production process, it is difficult to meet the environmental protection requirements. need

[0004] SCR (outside furnace denitrification), the desorption temperature is 320°C-380°C, the desorption efficiency is between 85%-95%, the desorption characteristics are limited by the temperature, and the powder concentration in the flue gas is strictly required. Therefore, the pre-stage must Denitrification can only be done after dust removal and purification. Since the desorption temperature cannot be too low, the dust collector can only be used for heat preservation and dust removal by electric dust collectors. It is still denitrification with catalyst outside the furnace. The operating site, operating cost, and input cost are very large. Compared with most enterprises, the economic burden is heavy and even unbearable.

SNCR+SCR combined process denitrification, the denitrification efficiency is relatively improved, although it meets the requirements of environmental protection standard improvement and compliance, but there are still the above-mentioned economic bearing problems

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