Melting method and system based on co-processing of fly ash and leachate in waste incineration plant

Abstract

The invention discloses a method for co-processing and melting fly ash and percolate in a waste incineration plant. The method comprises the following steps: 1) mixing fly ash and slag generated by the incineration plant or a slag former with the percolate or a concentrated solution of the percolate, and granulating; 2) carrying out hot air cyclone drying on the mixed granulation material; (3) carrying out plasma melting treatment on the granulated material subjected to cyclone drying; (4) the hot flue gas obtained after cyclone drying and the flue gas of the plasma melting furnace are merged into a secondary combustion chamber of an incineration plant for secondary combustion; (5) flue gas waste heat is utilized for heating air circulation cyclone drying; fly ash generated by an incineration plant and a leachate concentrated solution are mixed and granulated, plasma melting treatment is performed after cyclone drying, generated flue gas enters a secondary combustion chamber of the incineration plant for collaborative incineration treatment, and slag is subjected to water quenching to obtain a glassy product for resource utilization. The removal of dioxin and organic matters in the fly ash and the leachate and the effective fixation of heavy metals are realized, the treatment system is simple, and the dual effects of harmless recycling of the fly ash and the leachate concentrated solution are realized.

Description

technical field [0001] The invention belongs to the field of environmental protection technology and equipment, and in particular relates to a melting method and system based on the co-processing of fly ash and leachate of waste incineration plants. Background technique [0002] Fly ash is a powder material with light bulk density and small particle size collected in flue gas pipes, flue gas purification, separators and dust collectors during the waste incineration process. Fly ash has complex components and high toxicity. It not only contains a large amount of heavy metal inorganic harmful substances such as Cd, Cr, Cu, Ni, Pb, Zn and Hg, but also enriches the most toxic organic carcinogens such as dioxin. Designated hazardous waste (code HW18). In recent years, the waste incineration industry has grown explosively. For the currently commonly used grate furnaces, about 3%-5% of fly ash is produced per ton of waste incinerated, and the chloride ion content in fly ash is abo...

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Problems solved by technology

[0003] At the same time, collecting and storing garbage (garbage stacking) in the garbage incineration plant will produce a large amount of landfill leachate. The leachate of the incineration plant has the characteristics of high ammonia nitrogen content, high concentration of organic pollutants, high salt content, and complex components. The applicant has A number of patented technologies for landfill leachate, but the treatment of leachate will still produce a 13% to 30% concentrate, and the high pollutant concentration and low biodegradability of the leachate concentrate make it a highly environmentally friendly potential source of contamination

In recent years, many newly built waste incineration plants have required leachate reuse and "zero discharge" requirements, which put forward higher requirements for the design of leachate treatment systems. The concentration treatment methods mainly include membrane-based technology and evaporation. Technology reduction method; harmless treatment mainly covers coagulation / electrocoagulation, adsorption and advanced oxidation technologies, the overall investment is large, the operating cost is high, and the service life of the equipment will be shortened

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