A combined denitrification device and method for a layer-fired boiler

Abstract

The invention belongs to the field of coal layer combustion boiler pollutant discharge control and discloses a layer combustion boiler combination denitration device and method. The invention aims to enable NOx discharged by layer combustion boilers to reach the standard. A vaporizing chamber is arranged below the front arch in a hearth, and the partition of the hearth is provided with a gas outlet. A vaporization air chamber, a first air chamber, a second air chamber, a third air chamber, a fourth air chamber and a fifth air chamber are sequentially formed below a fire grate from front to back. A secondary air port is formed in the part, above the front arch, of the front wall of the hearth. The outlet of the hearth is communicated with the inlet of a horizontal type cyclone separator with an acceleration section, and the bottom of the horizontal type cyclone separator with the acceleration section is communicated with a main combustion zone of the lower part of the hearth through a return valve. The horizontal type cyclone separator with the acceleration section is sequentially communicated with a convection calandria, an economizer and an air pre-heating device, the air pre-heating device is communicated with a dust remover, the dust remover is communicated with a recycling fan and a draught fan, and the recycling fan is communicated with a smoke channel. An air supply fan is communicated with the vaporization air chamber, the first air chamber, the second air chamber, the third air chamber, the fourth air chamber, the fifth air chamber and the secondary air port. The layer combustion boiler combination denitration device and method are used for layer combustion boiler combination denitration.

Description

technical field [0001] The invention relates to the control of NO by layer combustion furnace x The device and method for discharging belong to the field of pollutant emission control of coal-fired seam-fired boilers. Background technique [0002] Layer-burning furnaces are often used in concentrated urban residential areas, and most of them emit low-altitude emissions, which makes industrial boilers particularly pollute the surrounding environment, especially urban environments, while NO x Occupies a large share of pollutants, so it is economically effective to reduce the NO of the layer combustion furnace x Emissions play a very important role in reducing air pollution. [0003] At present, the NOx emission concentration of floor-fired boilers cannot meet the emission standards of GB13271-2014, and the simple SNCR is also difficult to meet the standards. Although the use of SCR at the tail can meet the standards, the investment and operation costs are high, and users are...

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Problems solved by technology

This method uses natural gas as the reburning gas. The price of natural gas is very high, which greatly increases the operating cost and is difficult to implement in practical applications.

(2) In-furnace SNCR denitrification technology, that is, spraying urea in the furnace to react with the generated NOx to form N 2 , to reduce NOx emissions, but due to the large section of the furnace, it is difficult for the urea sprayed into the furnace to mix evenly with the flue gas on the entire section of the furnace, resulting in poor denitration effect, and the denitration rate is generally only about 40%.

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