High-pressure-head low-flow non-isolated online cleaning device for rotary air preheater

Abstract

The invention provides a high-pressure-head low-flow non-isolated online cleaning device for a rotary air preheater.The device comprises a steam heating device, an electric heating device, a water tank, an agentia adding device, a high-pressure water pump and a soot blower, wherein the water tank, the agentia adding device, the high-pressure water pump and the soot blower are sequentially connected, and the steam heating device and the electric heating device are both arranged in the water tank.The device is simple in structure, convenient to implement, small in influence on unit operation, and capable of efficiently cleaning a heat exchanging element of the rotary air preheater under the online non-isolated condition.

Description

technical field [0001] The invention belongs to the technical field of power station boiler auxiliary equipment, and in particular relates to a high-pressure head low-flow non-isolated on-line cleaning device for a rotary air preheater. Background technique [0002] Rotary air preheater (referred to as "air preheater") is widely used in large-capacity coal-fired power generation units in my country. Due to the narrow circulation space, this type of air preheater is prone to dust deposition. [0003] In recent years, with the continuous improvement of national environmental protection requirements, the large-scale coal-fired power generation units in service have basically completed the SCR denitrification transformation. After installing the SCR denitrification device, the unreacted and escaped NH in the denitrification system 3 with SO in flue gas 3 Easily reacts to form gaseous NH 4 HSO 4 , under certain conditions, deposit and condense on the surface of the air prehea...

AI Technical Summary

Problems solved by technology

[0009] (1) Affect the service life of the air preheater components and the exhaust gas temperature of the unit under low load operation

[0010] The heating element of the air preheater is quenched by high-pressure water, resulting in irregular expansion and contraction, which increases the risk of dynamic and static wear. The enamel material plated on the surface of the heat exchange element is prone to internal stress due to the alternation of cold and heat, causing it to fall off, shortening its service life; The online flushing of the preheater may affect the low-load applicability of the unit, affect the flue gas temperature, and further affect the primary and secondary air temperatures. In severe cases, the flushing work may be suspended

[0011] (2) The washing efficiency of stubborn hard dirt is low and the washing time is too long

Due to the high viscosity of ammonium bisulfate, the surface of the air preheater heat exchange element of the denitrification unit is thick and hard, and it takes a long time to wash it off

At present, the high-load operation time of domestic units is difficult to last for a long time, and many units do not have the conditions for high-pressure water cleaning. Therefore, how to efficiently remove dirt in a short period of time has become a problem that high-pressure water cleaning technology needs to solve

[0013] (3) The water injection volume is unevenly distributed in the radial direction of the air preheater

When the rotor rotates, each heat transfer element obtains the same angular velocity ω, and the distance between the heat transfer element and the center of the rotating shaft is set as r, then the linear velocity v=ωr obtained by each heat transfer element, the traditional water flushing scheme is The spray flow rate in the radial direction of the rotor rotor is Q 0 , then the amount of water sprayed by the unit rotor in the radial direction is q 0 =Q 0 / v=Q 0 / ωr,Q 0 and ω are constants, it can be seen that the amount of water sprayed by the unit rotor is q 0 It is inversely proportional to the distance r between the heat transfer element and the center of the rotating shaft, that is, the farther the heat exchanging element is from the rotating shaft, the less water spraying is obtained, which causes the heat exchanging element to obtain different water spraying impact force along the radial direction of the rotor. The ash removal capacity decreases linearly and cannot effectively remove ash in the entire rotor section

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