Green and efficient incineration method for hazardous waste in rotary kiln based on oxygen enriched air supply in secondary combustion chamber

Abstract

The invention discloses a green and efficient incineration method for hazardous waste in a rotary kiln based on oxygen enriched air supply in a secondary combustion chamber. The method comprises the steps of (1) adding solid waste, liquid waste and a first combustion-supporting gas to the rotary kiln for performing treatment; (2) feeding the waste and the liquid waste which are treated by means ofthe rotary kiln and a second combustion-supporting gas into a secondary combustion chamber for performing combusting treatment; and (3) exhausting the gas which is obtained after the combustion in the secondary combustion chamber, wherein the second combustion-supporting gas is formed by mixing air and an oxygen enriched gas; the incineration temperature in the secondary combustion chamber is risen to 1,100 to 1,200 DEG C; the oxygen concentration of the second combustion-supporting gas is 23 to 28 percent; the oxygen content of a combustion environment in the secondary combustion chamber isimproved, and a technical means of the preheating is effectively utilized, which are beneficial to removing nitrogen oxides from flue gas in a waste heat utilization system under the condition of ensuring complete decomposition of the harmful substances, such as dioxin; the production and emission of secondary environment pollution substances in an incineration processing process are avoided or remarkably reduced; and efficient and green treatment of maximum reduction of the hazardous waste is realized.

Description

technical field [0001] The invention relates to a green and high-efficiency hazardous waste rotary kiln incineration treatment method based on oxygen-enriched air supply from a secondary combustion chamber, which is used for incineration treatment of hazardous waste. Background technique [0002] The rapid economic development and the rapid advancement of industrialization have led to an increase in the output of hazardous waste. The environmental pollution caused by hazardous waste poses a serious threat to human survival and has become a major environmental problem faced by countries all over the world today. As the most difficult pollutants in the "three wastes" (waste water, waste gas and solid waste produced by industrial pollution sources), hazardous waste refers to the hazardous waste listed in the national hazardous waste list or determined according to the national hazardous waste identification standards and methods. For wastes with hazardous characteristics, the h...

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Problems solved by technology

[0008] Dioxin will decompose quickly above 850°C, but it can be easily synthesized at a temperature of 250°C to 350°C under reducing conditions containing copper, iron and other metal compounds as catalysts and high CO concentration

(2) The processing capacity of the flue gas purification system and the comprehensive utilization of heat energy: In order to reduce the content of CO to inhibit the synthesis of dioxins and achieve the temperature required for the full oxidation and decomposition of dioxins at high temperature, a large amount of carbon dioxide is required during the incineration process of the rotary kiln Excess air and additional combustion-supporting fuel (the disposal of hazardous waste with high humidity and low flammability requires a large amount of fuel to make the cost high), resulting in a large amount of tail gas to be treated

In actual treatment, it is generally selected to spray into the corresponding temperature section in the middle of the waste heat boiler (the method of spraying water or spraying cold air on the flue gas outlet pipe of the second combustion chamber to reduce the flue gas temperature is used to achieve the best denitrification temperature, but this will inevitably lead to loss of a certain amount of heat energy), but not only the denitrification reaction temperature is difficult to accurately control, but also shortens the denitrification process and requires the addition of more reducing agents (urea or ammonia water), which undoubtedly increases operating costs

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