Purification system and purification method for flue gas from industrial incinerator

Abstract

The invention relates to a purification system and purification method for flue gas from an industrial incinerator, belonging to the technical field of industrial incineration flue gas treatment. Thepurification system comprises a waste heat boiler, a first-stage dry treatment unit, a quenching treatment unit and a second-stage dry treatment unit. According to the invention, high-temperature fluegas of the incinerator is cooled through the waste heat boiler, and heat is recycled; the flue gas is primarily purified by the first-stage dry treatment unit; then, the flue gas is rapidly cooled toa temperature within 200 DEG C through the quenching treatment unit, and therefore, the optimal dioxin synthesis temperature range of 500-300 DEG C is crossed, secondary synthesis of dioxin is avoided and saturated steam is by-produced to recover the heat of the flue gas; finally, the flue gas is thoroughly purified through the second-stage dry treatment unit; heat is continuously recycled through an economizer, and high-altitude emission is completed under the action of an induced draft fan and a chimney; and therefore, various problems caused by water spraying quenching are effectively avoided, the catalytic denitration efficiency of flue gas is improved, extra energy is not consumed, and meanwhile, heat generated in the flue gas purification process is recycled to the maximum extent.

Description

technical field [0001] The invention relates to the technical field of industrial incineration flue gas treatment, in particular to an industrial incinerator flue gas purification system and a purification method thereof. Background technique [0002] Dioxin is a highly toxic polychlorinated biphenyl compound, which has strong carcinogenic and teratogenic effects, and can cause serious secondary pollution to air, soil and water. Dioxins mainly come from industrial smelting and industrial waste incineration. In industrial smelting, such as scrap copper smelting, if the cooling method is not selected properly, dioxins will be accompanied by the high-temperature flue gas (850°C) cooling process, and dioxins produced by waste incineration are It can be summarized as follows: [0003] (1) High temperature gas phase synthesis. Due to the adverse effects of low calorific value of waste, unstable feed, and high content of chlorine source waste (such as PVC, medical waste) mixed in...

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Problems solved by technology

[0015] However, the arrangement of the two-section shell and one bundle of tubes in the quenching heat exchanger does not consider the volume shrinkage caused by the rapid cooling of the pyrolysis gas. The necessary flow velocity is achieved in the tube bundle of the second-stage shell, so it is difficult to ensure the heat transfer coefficient and the necessary quenching efficiency of the gas side in the second-stage shell

[0016] Therefore, the above improved method does not actually solve the problem of rapid and rapid cooling of the flue gas to jump over the sensitive generation temperature zone of dioxins, while taking into account the high heat transfer coefficient on the flue gas side and the necessary heat transfer area to achieve waste heat recovery. conflict between

[0017] In addition, there are still two problems in the flue gas purification of conventional industrial incinerators: the low-temperature SCR is installed after the bag filter, and additional gas heating or steam heating is required to raise the temperature of the flue gas to the temperature required for the SCR catalytic reaction; the second is First-stage dry deacidification (semi-dry tower) + lye wet deacidification produces a large amount of effluent wastewater, which may dissolve and adsorb fine powder of dioxins and heavy metal chlorides. Compared with only adsorbing dioxins and Small amounts of fine powders of heavy metal chlorides, which are more difficult to handle

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