System and process for treating incineration fly ash through synergism of thermal desorption and carbon neutralization

Abstract

The invention discloses a system and a process for treating incineration fly ash through synergism of thermal desorption and carbon neutralization. The system comprises a dioxin thermal desorption device, a water washing dechlorination device, a multi-stage carbon neutralization device, a solid-liquid separation device, a heavy metal solidification device, an evaporative crystallization salt separation device and a heat exchange device; a CO2-containing medium circulating in the multi-stage carbon neutralization device can react with calcium and magnesium in washed slurry to generate carbonate, so that an agentia can be replaced to implement hardness regulation, the usage amount of the agentia is reduced, and meanwhile, the aim of carbon emission reduction is fulfilled; and a process route of dioxin anaerobic thermal removal, water washing dechlorination, CO2 decalcification and magnesium removal, heavy metal solidification and evaporative crystallization salt separation is adopted, so that a large number of reagents do not need to be added to remove calcium and magnesium ions when the washed slurry is treated, but the pH value of the washed slurry is neutralized through the CO2-containing medium, thereby greatly reducing the adding amount of a hardness adjusting agentia, reducing the operation cost, effectively reducing the difficulty of evaporative crystallization salt separation and improving the quality of recovered industrial salt.

Description

technical field [0001] The invention relates to the technical field of processing incineration fly ash, in particular to a system and process for processing incineration fly ash with thermal desorption and carbon neutralization. Background technique [0002] Domestic waste incineration treatment technology has become one of the most important and effective technologies for waste treatment in various countries due to its advantages of harmlessness, resource utilization, and volume reduction. However, as an inevitable product of waste incineration, incineration fly ash has been included in the hazardous waste list for management due to the dual pollution emission characteristics of dioxin and heavy metal leaching. [0003] Anaerobic heat treatment technology is a common method for reducing dioxins in fly ash. Dioxin molecules are desorbed or decomposed under anaerobic heating conditions. After treatment, fly ash can be combined with water elution and chlorine removal process t...

AI Technical Summary

Problems solved by technology

This method needs to consume a large amount of chemical reagents, and the operating cost is high. The addition of a large amount of chemical reagents will also introduce other impurities, which will bring difficulties to the subsequent salt separation process.

[0004] To sum up, the current fly ash harmless and resourceful treatment technology for fly ash washing liquid is still not reasonable enough, the amount of chemicals added is large, and the cost is high. There is an influence on the purity of

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