Method for preventing blockage of heat storage element of rotary air preheater of coal-fired power plant boiler

Abstract

The invention discloses a method for preventing blockage of a heat storage element of a rotary air preheater of a coal-fired power plant boiler. When the resistance of the air preheater is increased by 15%-20% than a design value, the rotational speed of the air preheater is adjusted according to the unit load and the exhaust gas temperature of an outlet of the air preheater to increase the temperature of the cold end of the air preheater; the air preheater runs continuously at a low speed, and when the resistance decreases to the required level, the normal operation of the air preheater is resumed; by reducing the rotational speed of the air preheater, the exhaust gas temperature is increased; and when the rotational speed of the air preheater is reduced, the heat storage capacity of theheat storage element is increased, the exhaust gas temperature can be greatly increased, the cold end integrated temperature of the air preheater is increased, and the flue gas temperature in the middle portion of the heat storage element reaches 250 DEG C, so that ammonium hydrogen sulfate is sublimated. The method has the advantages that the purposes of removing ammonium hydrogen sulfate originally attached to the surface of the heat storage element and reducing the resistance of the air preheater are achieved, the boiler efficiency is improved, the power consumption rate of a plant is lowered, and hidden dangers of lowering output or even halt of a power station are eliminated.

Description

technical field [0001] The invention relates to a method for preventing heat storage elements from being blocked, in particular to a method for preventing heat storage elements from being blocked in a rotary air preheater of a coal-fired power station boiler, and belongs to the field of methods for preventing heat storage elements from being blocked. Background technique [0002] The air preheater of the coal-fired boiler (hereinafter referred to as the air preheater) is a heat exchange device that preheats the air before entering the boiler to a certain temperature through the heat of the flue gas at the tail of the boiler through the internal heat storage element. The air preheater rotates slowly when it is working, the flue gas enters the flue gas side of the air preheater and then is discharged, and the heat carried in the flue gas is absorbed by the heat storage element in the air preheater, and then with the The boiler rotates slowly, the heat storage element moves to ...

AI Technical Summary

Problems solved by technology

The temperature gradient of the air preheater is 320°C-120°C, and ammonium bisulfate is easily bonded and deposited in the middle of the heat storage element. In recent years, with the development of clean energy, the state requires coal-fired power stations to deepen peak regulation. The temperature of the air preheater The gradient even reaches 280°C-100°C, and the accumulation of ammonium bisulfate increases, resulting in the blockage of the heat storage element channel and the increase in the resistance of the air preheater. This problem is a universal problem that needs to be solved urgently for SCR process denitrification power plant boilers.

[0005] At present, the traditional way is to reduce the accumulation of ammonium bisulfate by increasing the frequency of steam soot blowing, increasing the pressure of soot blowing, on-line water flushing, using sound wave purging, shock wave purging, etc., but the effect is poor

Improving the comprehensive cold end temperature of the air preheater is the most effective way to reduce the accumulation of ammonium bisulfate at present, but the range of increasing the comprehensive temperature of the cold end by using heaters and hot air recirculation is limited, and it has not achieved the goal of greatly reducing the accumulation of ammonium bisulfate Effect