Method for removing sulfur trioxide from coal-fired flue gas

A technology for sulfur trioxide and coal-fired flue gas, which is applied in chemical instruments and methods, separation methods, and dispersed particle separation, etc., can solve problems such as clogging and corrosion of air preheaters, reduce reactions, reduce Good dispersion effect

Active Publication Date: 2016-04-13
BEIJING SPC ENVIRONMENT PROTECTION TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Moreover, the smaller the particle size, the larger the relative specific surface area, and the higher the degree of contact with sulfur trioxide, so the reaction effect is better. Therefore, seeking a WSI process with high efficiency and small dosage is to solve the problem of sulfur trioxide and SCR denitrification. An effective method for the reaction of ammonia escaped from the reactor to form ammonium bisulfate and cause the plugging and corrosion of the air preheater

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] Choose a mixture of powdered sodium carbonate and sodium bicarbonate as the main absorbent, a mixture of powdered calcium carbonate and magnesium carbonate as an additive, the ratio of sodium carbonate and sodium bicarbonate is 1:0.03, and the ratio of calcium carbonate and magnesium carbonate is 1 :0.12.

[0023] First, to prepare a liquid absorbent, dissolve the mixture of powdered sodium carbonate and sodium bicarbonate and prepare a 10% concentration of the main absorbent solution with diluted water. The ratio of the main absorbent to the additive is 1:0.001. The additives are added to the prepared main absorbent solution to form a liquid absorbent; the smoke exhaust channel of the power plant is equipped with a selective catalytic reduction (SCR) denitrification device and an air preheater in sequence from top to bottom. The concentration of sulfur trioxide in the flue gas between the outlet of the denitrification reactor and the inlet of the air preheater is 56.5m...

Embodiment 2

[0025] Choose powdered sodium carbonate as the main absorbent and powdered calcium carbonate as the additive.

[0026] First, prepare the liquid absorbent, dissolve the powdered sodium carbonate and prepare a 15% main absorbent solution with dilution water, add the additive to the prepared main absorbent according to the ratio of the main absorbent to the additive at a ratio of 1:0.05 Absorbent solution to form a liquid absorbent; a selective catalytic reduction (SCR) denitrification device and an air preheater are arranged in sequence from top to bottom in the flue gas exhaust channel of the power plant, and the flue gas passing through the outlet of the denitrification reactor and the air The concentration of sulfur trioxide in the flue gas between the inlets of the preheater is 56.5mg / Nm 3 When using compressed air to atomize the liquid absorbent, the pressure is 0.05MPa, and then spray the atomized liquid absorbent into the flue gas channel between the outlet end of the de...

Embodiment 3

[0028] Powdered sodium bicarbonate is selected as the main absorbent, and a mixture of powdered calcium carbonate, magnesium carbonate and magnesium hydroxide is used as an additive, and the ratio of calcium carbonate, magnesium carbonate and magnesium hydroxide is 1:0.02:0.02.

[0029] First, prepare the liquid absorbent, dissolve the powdered sodium bicarbonate and prepare a 20% main absorbent solution with dilution water, and add the additive to the prepared absorbent according to the ratio of the main absorbent to the additive at a ratio of 1:0.2 The main absorbent solution forms a liquid absorbent; the exhaust channel of the power plant is sequentially equipped with a selective catalytic reduction (SCR) denitrification device and an air preheater, and it is monitored that the flue gas passes through the outlet of the denitrification reactor and The concentration of sulfur trioxide in the flue gas between the inlets of the air preheater is 56.5mg / Nm 3When using compressed ...

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PUM

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Abstract

The invention provides a method for removing sulfur trioxide from coal-fired flue gas. According to the concentration of sulfur trioxide in outlet flue gas of a selective catalytic reduction (SCR) denitration device, a prepared liquid absorbent is sprayed to flue gas in a flue gas passage between the outlet end of the SCR denitration device and an air preheater, and the spraying amount of the liquid absorbent per unit volume of the flue gas is 1-20 times of the mole number of sulfur trioxide required to be removed from the per unit volume of the flue gas. Through the gas-liquid reaction between the liquid absorbent and the sulfur trioxide in the flue gas, sulfur trioxide in the flue gas is removed. The liquid absorbent enters the flue duct in a spraying manner and is atomized into small droplets; the small droplets are evaporated in high-temperature flue gas to form tiny absorbent particles. The particles are large in relatively specific surface area and better in dispersion in the flue gas passage, and can be in contact with sulfur trioxide more fully to enable the reaction to be more fully, so that the concentration of sulfur trioxide in flue gas is greatly reduced, the generation of ammonium bisulfate is reduced, and corrosion and blockage of the air preheater are avoided.

Description

technical field [0001] The invention belongs to the technical field of air pollutant control, in particular to a method for removing sulfur trioxide in coal-fired flue gas. Background technique [0002] The combustion of sulfur-containing coal will produce a certain amount of sulfur dioxide and sulfur trioxide gas. After the coal-fired power plant is equipped with a selective catalytic reduction (SCR) denitrification device, the denitrification catalyst not only converts nitrogen monoxide and nitrogen dioxide in the flue gas into nitrogen, but also promotes the conversion of sulfur dioxide into sulfur trioxide. Therefore, the content of sulfur trioxide in the flue gas has nearly doubled compared with that without the installation of the SCR denitrification device. [0003] Sulfur trioxide reacts with ammonia slipping from the SCR reactor to form ammonium bisulfate (ABS). The melting point of ammonium bisulfate is 147°C, and ammonium bisulfate exists in liquid form in the f...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D53/78B01D53/50
CPCB01D53/502B01D2251/304B01D2251/606
Inventor 张开元周欣程俊峰张甜甜王红蕾
Owner BEIJING SPC ENVIRONMENT PROTECTION TECH
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