Now?Refuse incineratorThere are three main criteria for equal distribution: ① the type of grate; ② The way and intensity of grate movement; ③ The inclination angle of the grate and the direction of garbage movement on the grate surface, etc; Only by passing these three major scoring criteria can we better ensure the timely ignition, full combustion, and burnout of garbage. The grate should be divided into three areas: drying and ignition zone, main incineration zone, and ash burnout zone;
The technology of garbage incineration has gone through nearly 130 years of development, and the technology and equipment of garbage incinerators have become increasingly perfect and widely used. The commonly used waste incineration systems in developed Western countries mainly include the following categories:
(1) Garbage layer incineration system, such as using rolling grate, horizontal reciprocating feeding grate, and inclined reciprocating grate (including forward and reverse thrust inclined reciprocating grate), etc. The main feature of layer burning incineration method is that the waste does not require strict pretreatment. Rolling grate and reciprocating grate have strong ignition function and are more suitable for the incineration of low calorific value and high ash urban waste;
(2) The fluidized bed incineration system is characterized by suspended combustion of garbage, full contact between air and garbage, and good combustion effect. However, fluidized bed combustion requires fuel with relatively uniform particle size and uniform fuel feeding, making it generally difficult to incinerate large pieces of waste. Therefore, fluidized bed incineration systems have strict requirements for waste pretreatment, which limits their development in the fields of industrial waste and urban waste incineration;
(3) The rotary cylinder incinerator is characterized by feeding garbage into a continuous and slowly rotating cylinder for incineration until it is completely burned, thus achieving good contact between garbage and air and uniform and sufficient combustion. Western countries often use this type of incinerator for the treatment of toxic and hazardous industrial waste.
In today's highly industrialized era, urban waste incineration technology is facing many new situations and problems:
In economically developed countries, urban waste has a low density, high calorific value, and low ash and moisture content;
2. The emission standards for garbage incineration are becoming increasingly strict, especially requiring effective control of harmful substances in flue gas emissions. In addition to smoke and dust, the main harmful substances in waste incineration flue gas include CO, SOx, NOx, organic carbon, as well as dioxins and furans. By improving combustion technology and adjusting the incineration process, the production and emissions of these substances can be controlled to a certain extent. Compared to before the 1950s, there were only restrictions on the smoke emissions and incineration temperature of garbage incinerators. The purpose of setting the incineration temperature (such as 800 ℃) is to fully incinerate harmful substances that produce irritating odors in the furnace;
From the perspective of investment and operational economy of the incinerator, its incineration capacity should be between 3t/h and 20-25t/h. Therefore, modern waste incineration systems should meet the following requirements:
(1) Strong ignition function to ensure even and complete combustion of garbage on the entire grate surface and prevent slagging. The main factors affecting the ignition function of the grate are: ① the type of grate; ② The way and intensity of grate movement; ③ The inclination angle of the grate and the direction of garbage movement on the grate surface, etc; In order to ensure timely ignition, full combustion, and burnout of garbage, the grate should be divided into three areas: drying and ignition zone, main incineration zone, and ash burnout zone;
(3) Combustion equipment should have the ability to adapt to sudden fluctuations in waste components (moisture or calorific value) that occur frequently. When the composition of the garbage fluctuates, the amount of garbage fed to the incinerator, as well as the distribution and temperature of the primary air flow, should be adjusted promptly and accurately;
(4) Preheat the combustion air (primary and secondary air);
(5) The possibility of introducing certain additives to reduce the emissions of harmful substances such as NOx and SOx;
(6) The entire combustion process is divided into a waste incineration stage and a combustion stage of combustible and harmful substances in the flue gas, with sufficient air required for the combustion of the flue gas in the latter stage. During the waste incineration stage, it is necessary to limit the amount of combustion air to avoid strong fluctuations in furnace temperature and excessive generation of fly ash
(7) Ensure low carbon content (1-3%) in ash and fly ash, and good burnout.
The technology of garbage incineration has gone through nearly 130 years of development, and the technology and equipment of garbage incinerators have become increasingly perfect and widely used. The commonly used waste incineration systems in developed Western countries mainly include the following categories:
(1) Garbage layer incineration system, such as using rolling grate, horizontal reciprocating feeding grate, and inclined reciprocating grate (including forward and reverse thrust inclined reciprocating grate), etc. The main feature of layer burning incineration method is that the waste does not require strict pretreatment. Rolling grate and reciprocating grate have strong ignition function and are more suitable for the incineration of low calorific value and high ash urban waste;
(2) The fluidized bed incineration system is characterized by suspended combustion of garbage, full contact between air and garbage, and good combustion effect. However, fluidized bed combustion requires fuel with relatively uniform particle size and uniform fuel feeding, making it generally difficult to incinerate large pieces of waste. Therefore, fluidized bed incineration systems have strict requirements for waste pretreatment, which limits their development in the fields of industrial waste and urban waste incineration;
(3) The rotary cylinder incinerator is characterized by feeding garbage into a continuous and slowly rotating cylinder for incineration until it is completely burned, thus achieving good contact between garbage and air and uniform and sufficient combustion. Western countries often use this type of incinerator for the treatment of toxic and hazardous industrial waste.
In today's highly industrialized era, urban waste incineration technology is facing many new situations and problems:
In economically developed countries, urban waste has a low density, high calorific value, and low ash and moisture content;
2. The emission standards for garbage incineration are becoming increasingly strict, especially requiring effective control of harmful substances in flue gas emissions. In addition to smoke and dust, the main harmful substances in waste incineration flue gas include CO, SOx, NOx, organic carbon, as well as dioxins and furans. By improving combustion technology and adjusting the incineration process, the production and emissions of these substances can be controlled to a certain extent. Compared to before the 1950s, there were only restrictions on the smoke emissions and incineration temperature of garbage incinerators. The purpose of setting the incineration temperature (such as 800 ℃) is to fully incinerate harmful substances that produce irritating odors in the furnace;
From the perspective of investment and operational economy of the incinerator, its incineration capacity should be between 3t/h and 20-25t/h. Therefore, modern waste incineration systems should meet the following requirements:
(1) Strong ignition function to ensure even and complete combustion of garbage on the entire grate surface and prevent slagging. The main factors affecting the ignition function of the grate are: ① the type of grate; ② The way and intensity of grate movement; ③ The inclination angle of the grate and the direction of garbage movement on the grate surface, etc; In order to ensure timely ignition, full combustion, and burnout of garbage, the grate should be divided into three areas: drying and ignition zone, main incineration zone, and ash burnout zone;
(3) Combustion equipment should have the ability to adapt to sudden fluctuations in waste components (moisture or calorific value) that occur frequently. When the composition of the garbage fluctuates, the amount of garbage fed to the incinerator, as well as the distribution and temperature of the primary air flow, should be adjusted promptly and accurately;
(4) Preheat the combustion air (primary and secondary air);
(5) The possibility of introducing certain additives to reduce the emissions of harmful substances such as NOx and SOx;
(6) The entire combustion process is divided into a waste incineration stage and a combustion stage of combustible and harmful substances in the flue gas, with sufficient air required for the combustion of the flue gas in the latter stage. During the waste incineration stage, it is necessary to limit the amount of combustion air to avoid strong fluctuations in furnace temperature and excessive generation of fly ash
(7) Ensure low carbon content (1-3%) in ash and fly ash, and good burnout.
