SCR temperature regulating system of boiler and method for regulating smoke temperature of SCR inlet of boiler

Abstract

The invention discloses an SCR temperature regulating system of a boiler and a method for regulating a smoke temperature of a SCR inlet of the boiler. The SCR temperature regulating system of the boiler comprises an economizer, wherein the economizer comprises an economizer outlet collection box which is communicated with the boiler and an economizer inlet collection box which is communicated with the boiler, the economizer inlet collection box is connected with a boiler feed pipe, and the boiler feed pipe or the economizer inlet collection box is communicated with a temperature regulating device which regulates the heat absorption working medium flow of the boiler feed pipe. The SCR temperature regulating system of the boiler and the method for regulating the smoke temperature of the SCR inlet of the boiler can control the smoke temperature to be within a normal working temperature range and guarantee activity of catalysts. In addition, only the temperature regulating device needs to be additionally arranged on the outer portion of the economizer, internal parts in existing equipment in a boiler system do not need to be refitted, and the SCR temperature regulating system of the boiler and the method for regulating the smoke temperature of the SCR inlet of the boiler are beneficial to reduction of refitting difficulties and reduction of refitting cost.

Description

technical field [0001] The invention relates to the field of thermal power generation, in particular to a boiler SCR temperature regulation system and a method for regulating the boiler SCR inlet smoke temperature. Background technique [0002] Generally, during the operation of the boiler, the temperature change of the working fluid on the heating surface of the boiler and the flue gas temperature on each heating surface can meet the design requirements under the full load condition of the boiler. The air temperature cannot match the design temperature. According to the summary of many years of on-site commissioning and operation experience, the flue gas temperature at the outlet of the boiler economizer under the low-load condition of the general boiler is much lower than that under the full-load condition. The temperature is generally 350-400 degrees, and the flue gas temperature at the outlet of the economizer is less than 300 degrees under the boiler with 30% load cond...

AI Technical Summary

Problems solved by technology

[0004] At present, most of the denitrification catalysts in the domestic market are high-temperature catalysts, and the reasonable temperature is 350-400 degrees. SO in air 3 It is easy to chemically react with ammonia in the flue gas to form ammonium bisulfate. Ammonium bisulfate is in the form of a mucous membrane at around 250 degrees and easily adheres to the surface of the catalyst, resulting in reduced activity or even failure of the catalyst.

For this reason, it is very important to maintain a reasonable smoke temperature for high-temperature catalysts. For domestic coal-fired units that often operate at low loads, the SCR inlet smoke temperature cannot meet the catalyst operation requirements. Retrofit, by reducing the area of ​​the economizer heating surface before the SCR inlet, and adding part of the economizer heating surface behind the SCR, the main purpose is to prevent the flue gas temperature at the economizer outlet before the SCR inlet from being too low when the boiler is operating at low load Cause catalyst activity to decrease or fail, but for high-load boiler conditions, too high smoke temperature before the economizer outlet SCR inlet will also have a certain impact on catalyst activity, and the investment cost for heating surface transformation is relatively large

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