Method and equipment for preventing dioxin generation and achieving ultra-clean emission of flue gas

Abstract

The invention discloses a method and equipment for preventing dioxin generation and achieving ultra-clean emission of flue gas. The equipment comprises: a deacidification agent, a denitration agent, adeacidification agent bin, a metering feeder, a pneumatic powder injector, a gas-solid mixer, a dry type reaction tower, a flue channel, a ceramic fiber filtering pipe dust removing device, a flue gas outlet, a material return pipe 1, a high-temperature mill, a material return pipe 2, a denitration ammonia spraying system and an ash discharge valve. According to the method, flue gas produced by the combustion of an incinerator stays for more than 2 s at a high temperature of 850 DEG C, and then is gradually cooled to a temperature of 350-400 DEG C; the cooled flue gas enters the gas-solid mixer through a flue gas inlet, and is instantaneously mixed with the deacidification agent, and the denitration agent is sprayed by the denitration ammonia spraying system, such that the HCL, the Cl, the Cl2 and the SO2 in the soot are neutralized with the deacidification agent, and the chlorination reaction necessary in a dioxin synthesis reaction is terminated; and the obtained material enters thehigh-temperature ceramic fiber filtering pipe dust removing device, and contacts vanadium pentoxide so as to be subjected to a selective catalysis reaction, such that the NOx is decomposed into harmless N2 and H2O, and the dioxin is decomposed into CO2, H2O and HCl so as to achieve the ultra-clean emission.

Description

technical field [0001] The invention relates to a method and equipment for preventing the generation of dioxin and ultra-clean emission of flue gas, which belongs to the ultra-clean emission of domestic waste incineration, hazardous waste incineration, solid waste incineration and all incineration flue gas resynthesized with dioxin Methods and Apparatus. [0002] technical background [0003] my country produces more than 200 million tons of municipal solid waste every year, and the annual growth rate of waste has reached more than 10%. The growth rate obviously lags behind the growth rate of waste generation. Incineration and landfill are the two main domestic waste disposal methods in my country, and incineration inevitably produces a large amount of fly ash. [0004] The biggest feature of the fly ash in our country is the high chlorine content. The content of this volatile and interfering element can even be as high as 30%, which is rare in the world. In addition, waste i...

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Problems solved by technology

[0005] Dioxin is a strong carcinogenic by-product in fly ash produced by industry and waste incineration. In 2004, the total annual discharge of dioxin in my country was 10237g-TEQ. In the past ten years, my country has fully learned from developed countries. The successful experience of dioxin emission reduction, with the joint efforts of the competent authorities and all parties, has effectively controlled the growth trend of dioxin emissions, but my country is still at a stage where the total amount of dioxin emissions is quite high. Emission reduction still faces challenges and arduous tasks, and it is also the bottleneck that makes it difficult to achieve ultra-clean emission of flue gas

[0008] For example, in a method and equipment for producing fuel from domestic waste that curbs the generation of dioxins (publication number: CN103045273 A), when producing fuel from domestic waste, dioxins are not prevented from being generated, but are transferred to the place of existence along with the tar , causing secondary pollution

[0009] As a method for eliminating dioxins in flue gas (public number: CN 101249378 A), the removal efficiency of dioxins is only 50% to 90%, which cannot really prevent the generation of dioxins, and follow-up methods and equipment are still needed. Achieve ultra-clean emission of flue gas

[0010] For example, the medium-temperature dry circulating fluidized bed flue gas desulfurization method and device (publication number: CN 1214954 A), although the temperature range of 400 ° C to 800 ° C is adopted, but this patent is suitable for desulfurization and cannot meet the requirements of acid gas NO X , HCL and Cl 2 Ultra-clean emission requirements, the "steam activation" technology in this patent cannot be used for lime to absorb HCL and Cl 2 reaction product of

[0011] For example, a method for purifying high-temperature flue gas from a waste incinerator (public number: CN1179780C) and a method for purifying high-temperature flue gas from a waste incinerator (public number: CN1422689A), which add sodium-alkali modified Lime, although it can desulfurize and dechlorinate to curb the formation of dioxins, it is difficult to purify HCL and dioxins in accordance with the EU 2000 emission standards, and it is impossible to achieve simultaneous denitrification, dust removal, Decompose dioxin

[0012] None of the above methods to curb the discharge of dioxins can completely and effectively prevent the formation of dioxins and decompose residual dioxins, which cannot meet the ideal discharge standards

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