Desulphurization and denitration apparatus for flue gas of coal-fired boiler

Abstract

The invention provides a desulphurization and denitration apparatus for flue gas of a coal-fired boiler. The desulphurization and denitration apparatus comprises the coal-fired boiler, a flue-gas on-line monitoring and controlling device, an electric air inlet valve, a reaction tower, a bag-type dust collector, a fan, a desulfurization tower, a dehumidifying and purifying tower and a chimney. The apparatus is characterized in that the coal-fired boiler is successively connected with the flue-gas on-line monitoring and controlling device, the electric air inlet valve, the reaction tower, the bag-type dust collector, the fan, the desulfurization tower, the dehumidifying and purifying tower and the chimney; a bypass pipeline is arranged between and connected with the coal-fired boiler and the electric air inlet valve; the bypass pipeline is connected with the inlet of the chimney; a by-passing valve is arranged on the bypass pipeline; the outlet of electric air inlet valve is connected with the air inlet of the reaction tower; the lower part of the air inlet of the reaction tower is connected with a taper ash collecting groove; the taper ash collecting groove is connected with an electric cindervalve; and the upper part of the air inlet of the reaction tower is connected with a throat pipe. The desulphurization and denitration apparatus can remove pollutants like SO2 gas and nitrogen oxides in the flue gas of the coal-fired boiler, enables flue gas to be discharged after reaching the standard and avoids pollution to environment.

Description

technical field [0001] The invention relates to a coal-fired boiler flue gas desulfurization and denitrification device, specifically for purifying the flue gas produced by the coal-fired boiler, and belongs to the technical field of environmental protection. Background technique [0002] At present, the pulverized coal used in coal-fired boilers contains sulfur. During the high-temperature firing process at 1200°C to 1500°C, the sulfur in the raw materials reacts chemically to form SO 2 Into flue gas, SO emitted from coal-fired boilers 2 accounted for domestic SO 2 A large part of the total emissions, according to the analysis of the flue gas of coal-fired boilers, has the following characteristics: [0003] (1) The concentration of SO2 in the flue gas of coal-fired boilers changes very quickly and the concentration fluctuates greatly; [0004] (2) The temperature of flue gas emitted by coal-fired boilers usually fluctuates between 120°C and 160°C; [0005] (3) The dust...

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Problems solved by technology

[0008] To sum up, the temperature of flue gas emitted by coal-fired boilers is mostly between 120 and 160 °C, and the flue gas environment conditions are relatively harsh, such as high dust concentration, high oxygen content of flue gas, and low moisture content. high concentration of heavy metals, etc., in the case of using high-sulfur coal, the flue gas SO 2 The emission concentration reaches 5000~6000mg / Nm 3 , only the first-stage cycle dry desulfurization method can not achieve SO 2 Emission concentration 3 In addition, the NOx emission concentration reaches 600-800g / Nm 3 , causing serious pollution to the environment

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