SNCR denitration method for urea solutions of double concentrations

Abstract

The invention discloses an SNCR denitration method for urea solutions of double concentrations. A urea solution storage and preparation device (1), a urea preparation control module (3), an online attenuation module (3), a metering and distributing module (4), a reducing agent spraying module (5) and a urea solution spraying control device (6) are involved in the method, wherein the information input end of the urea solution storage and preparation device (1) is connected with the information input end of the urea preparation control module (2), and the control end of the urea preparation control module (2) is connected with the urea solution storage and preparation device (1). The urea solutions in two urea liquid storage tanks can be conveniently regulated to be of two different concentrations, and the concentration values are determined according to design calculation and site parameters; in this way, the regulation range is narrowed, accuracy is increased, and a denitration system conducts rapid reaction for the working condition changes of a boiler; particularly, under the low temperature of the downstream part of a window, the pure urea supply amount is rapidly increased, and the denitration efficiency is ensured.

Description

technical field [0001] The invention relates to the field of urea processing and production devices, in particular to an SNCR denitrification method for a double-concentration urea solution. Background technique [0002] The SNCR urea solution preparation and storage system should generally include: dry urea storage, urea solution preparation and storage system, online dilution system, back pressure control, and injection metering and distribution devices. Its function is to send urea solution to the injection system in a certain amount according to the NOx concentration at the boiler outlet. [0003] The system is equipped with a urea solution batching tank and two urea solution storage tanks. The batching tank is used to configure a certain concentration of urea solution, and the urea solution storage tank is used to store the urea solution prepared by the batching tank. The transfer pump is realized. The solution in the storage tank is pressurized by the pump and dilute...

AI Technical Summary

Problems solved by technology

[0005] Since the load change of small and medium-sized thermal power plant boilers, especially industrial boilers that only supply heat, is much larger than that of large-scale power plant boilers in actual operation, the temperature window of SNCR is an extremely narrow range, and SNCR technology is extremely sensitive to temperature conditions, NOx In the absence of catalysis, when the reaction temperature is lower than 750 degrees, the reduction reaction will become dull, and the denitrification efficiency will drop sharply or even be zero, and the online dilution device can only be adjusted within a certain range. If the range is too wide, it will affect the adjustment. Effect

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