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A kind of SNCR and SCR combined denitrification system and denitrification method of alumina roasting flue gas

A technology of alumina and aluminum hydroxide, applied in the field of SNCR and SCR combined denitration system, can solve the problems of weak alkalinity of aluminum materials, no desulfurization facilities, general SNCR effect, etc., and achieve the effect of compact system structure and cost saving.

Active Publication Date: 2020-09-04
INST OF PROCESS ENG CHINESE ACAD OF SCI
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the combined denitrification system and method of the alumina roasting flue gas also have the following disadvantages: the SNCR effect of alcoholic organic matter is general, the aluminum material itself in the system is relatively weak in alkalinity, and has a low 2 Absorption is also limited
However, the direct application of the SNCR device and SCR device to the treatment of alumina roasting flue gas has the following problems: the SCR denitrification of the system is low-temperature SCR denitrification, and desulfurization must be carried out before the low-temperature SCR denitrification, while alumina roasting flue gas sulfur dioxide The concentration is low, usually there is no desulfurization facility, and the temperature interval layout is not suitable for low-temperature SCR

Method used

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  • A kind of SNCR and SCR combined denitrification system and denitrification method of alumina roasting flue gas

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Effect test

Embodiment 1

[0043] A combined SNCR and SCR denitrification system for alumina roasting flue gas, such as figure 1 As shown, it includes a roasting furnace, a three-stage cyclone separator, a second-stage cyclone separator, a first-stage cyclone separator and a dust collector connected in sequence; the roasting furnace is provided with an alumina material inlet, and the three-stage cyclone separator and A dry aluminum hydroxide inlet is set between the secondary cyclone separator, a wet aluminum hydroxide inlet is set between the secondary cyclone separator and the primary cyclone separator, and an oxidation A primary SNCR device and a secondary SNCR device are arranged sequentially in the flow direction of the aluminum roasting flue gas, the primary SNCR device is connected to the organic amine compound supply device; the secondary SNCR device is connected to the ammonia supply device; the secondary cyclone An SCR device is installed between the separator and the wet aluminum hydroxide in...

Embodiment 2

[0052] A combined SNCR and SCR denitrification system for alumina roasting flue gas, comprising a roasting furnace, a three-stage cyclone separator, a secondary cyclone separator, a primary cyclone separator and a dust collector connected in sequence; the roasting furnace is provided with an oxidation Aluminum material inlet, a dry aluminum hydroxide inlet is set between the third-stage cyclone separator and the second-stage cyclone separator, and a wet aluminum hydroxide inlet is arranged between the second-stage cyclone separator and the first-stage cyclone separator. Between the roasting furnace and the three-stage cyclone separator, a primary SNCR device and a secondary SNCR device are sequentially arranged along the flow direction of the alumina roasting flue gas, and the primary SNCR device is connected to the organic amine compound supply device; the secondary SNCR device The device is connected to the first ammonia supply device; an SCR device is arranged between the se...

Embodiment 3

[0063] Using the SNCR and SCR combined denitrification system and denitrification method described in Example 1, the 500,000 tons / year alumina roaster was denitrated. In flue gas, the concentration of NOx is 500mg / m 3 , spray methylamine at the outlet of the roaster, the initial molar ratio of methylamine to flue gas NOx is 0.05:1, spray ammonia water at the entrance of the three-stage cyclone separator, and the initial molar ratio of ammonia to flue gas after gasification is 0.7 : 1, the reaction temperature of primary SNCR and secondary SNCR is 990°C, the reaction temperature of SCR is 350°C, and the NOx concentration at the flue gas outlet of alumina roasting is lower than 50mg / m 3 , The escape ammonia concentration in the tail gas is lower than 1ppm.

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Abstract

The present invention provides a SNCR and SCR combined denitration system for alumina roasting flue gas, and a denitration method thereof. According to the SNCR and SCR combined denitration system, a first-stage SNCR device and a second-stage SNCR device are sequentially arranged between the roasting furnace and the third-stage cyclone separator of an original alumina roasting system along the flowing direction of alumina roasting flue gas, the first-stage SNCR device is connected to a gas organic amine compound supply device, the second-stage SNCR device is connected to an ammonia supply device, and a SCR device is arranged between a second-stage cyclone separator and a wet aluminum hydroxide inlet. According to the present invention, the denitration system and the denitration method have advantages of high denitration efficiency and low ammonia escape, and can meet the increasingly stringent alumina roasting flue gas NOx emission standard.

Description

technical field [0001] The invention belongs to the technical field of pollutant control, and relates to an SNCR and SCR combined denitration system and a denitration method for alumina roasting flue gas. Background technique [0002] Nitrogen oxides (NOx) are one of the main sources of air pollution. It can form acid rain, and can also react photochemically with volatile organic compounds under light conditions to generate ozone and PM2.5. In recent years, with the gradual increase in energy consumption and the increasingly stringent environmental emission standards, the demand for NOx pollution control in various industries is urgent. [0003] The aluminum smelting industry has an extremely important position and role in my country's national economy and social development. However, in the aluminum smelting process, especially the alumina roasting process, the NOx emission intensity is relatively large. my country's alumina production generally adopts circulating fluidiz...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01D53/75B01D53/86B01D53/78B01D53/56B01D53/90B01D45/16
CPCB01D45/16B01D53/56B01D53/75B01D53/78B01D53/8628B01D53/90B01D2251/206B01D2251/2062B01D2251/2067B01D2255/20707B01D2255/20723B01D2255/20776B01D2258/0283
Inventor 朱廷钰刘霄龙王雪陈立施文博
Owner INST OF PROCESS ENG CHINESE ACAD OF SCI