Boiler water wall air film protection device

Abstract

Provided is a boiler water wall air film protection device. A plurality of tuyeres are arranged obliquely in an upstream boiler wall of high-temperature flame and flue gas coal dust airflow in the boiler water wall area and each tuyere communicate with an air flue arranged on the outer side of a hearth. Air is jetted into the hearth through the tuyeres, airflow forms an air curtain between the downstream portion of the flame and high-temperature flue gas flow and a water wall along the flue gas and the air curtain is towards the water wall under pushing of the flame and the high-temperature flue gas to form an air isolation layer, on the one hand, the action of the air curtain can push the wall-eroding coal dust airflow or flame to the center of the cross section of the hearth, so that erosive wear and corrosion to the water wall from the wall-eroding coal dust airflow or flame are avoided, and on the other hand, the air curtain is turned to the downstream water wall area under the action of the upstream high-temperature flame and flue gas, a layer of oxidizing atmosphere protection film is formed on the downstream water wall area, and the problem of high-temperature corrosion of the water wall is solved fundamentally.

Description

technical field [0001] The invention belongs to the field of boilers, and in particular relates to an air film protection device for boiler water walls. Background technique [0002] In recent years, with the implementation of the "Coal Power Energy Conservation and Emission Reduction Upgrading and Transformation Action Plan" [2014] No. 2093, coal-fired power plants have carried out a series of ultra-low emission transformations. To ensure that NO in flue gas x The emissions meet the emission standards and ease the operating pressure of the denitrification system. Most power plants have carried out low-nitrogen burner transformation or deep low-nitrogen burner transformation. However, under the low-nitrogen combustion mode, the main combustion area of ​​the boiler is in a weakly reducing atmosphere, and some water-cooled walls have a strong reducing atmosphere at the wall, and the H in the flue gas 2 The high content of S causes high temperature corrosion of the water-cool...

AI Technical Summary

Problems solved by technology

However, the sticking air technology has the following problems: (1) If the area of ​​the sticking wind nozzle is set too large, although it can effectively improve the reducing atmosphere near the water wall, due to the large area of ​​the sticking wind blowing nozzle, it will affect the original boiler air. Due to the impact of the dynamic field, problems such as overheating of the tube wall on the high-temperature heating surface, high NOx at the denitrification inlet, and high CO concentration at the tail; Good, can not play a role in preventing high temperature corrosion of the water wall

(2) Most of the wall-attached tuyeres are equipped with deflectors on the fire side of the furnace. These deflectors will burn and fall off due to flame erosion, high-temperature radiation and other reasons during operation, causing the wall-attached wind to fail to reach accurately and easily The water-cooled wall area corroded by high temperature cannot play the role of wall-attached wind

(3) The air source of the wall-attached air is generally taken from the hot secondary air box. However, since the air pressure of the hot secondary air box is about 1kPa during the operation of the boiler, the rigidity of the wall-attached air may be affected when the load of the unit is low.

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