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1. Background and significance of technology development Since the twentieth century, solid waste emissions have increased dramatically, causing increasingly serious problems such as air pollution, groundwater pollution, soil contamination, land occupation, and damage to natural landscapes. Solid waste is divided into two types: industrial waste and municipal waste. The output of municipal waste is staggering. According to statistics, China's total urban waste output in 1990 was 69 million tons, and Beijing's annual urban waste output exceeded 2 million tons. How to effectively deal with these urban wastes and make them resourceful, reduced and harmless (i.e. "three modernizations") has become a topic of great concern to countries all over the world. Commonly used treatment methods for municipal waste include landfill, composting, biogas production, reclamation, incineration and fluidized bed gas production. Among them, incineration and fluidized bed gas production are the best treatment methods, which meet the requirements of the "three modernizations". Due to the large investment and complex process equipment, the fluidized bed gas production method is still in the initial stage of research. Municipal waste incineration technology is developed in the United States, Japan, France, Germany, etc. * * It has been initially applied and has produced good environmental protection and economic benefits. The method of burning garbage and recycling energy is a major development direction for the treatment of urban garbage in my country. 2. Overview of foreign waste incineration power generation 1. Foreign waste-to-energy generation was the first country to conduct research and development on waste incineration technology in Germany. Subsequently, the United Kingdom, France, the United States, Japan and other countries also actively carried out research in this area. Germany currently has more than 50 devices for extracting energy from garbage and more than a dozen waste-to-energy plants, which are used for combined heat and power generation to effectively heat cities or provide industrial steam. In 1965, there were only 7 waste incinerators in the Federal Republic of Germany, processing 718,000 tons of waste annually, which could provide electricity for 4.1% of the total population. By 1985, the number of incinerators had increased to 46, processing more than 8 million tons of garbage annually, accounting for 30% of the total garbage, and providing electricity for 34% of the total population. In large cities such as Berlin, Hamburg, and Munich, 10.7% of civilian electricity comes from garbage incineration. In 1995, there were 67 waste incinerators in Germany, and the proportion of the population benefiting from them increased from 34% to 50%. There are about 300 garbage incinerators in France, which can process more than 40% of municipal waste. Paris has 4 garbage incineration plants with an annual processing capacity of 1.7 million tons, accounting for 90% of the city's total garbage. The energy collected is equivalent to 200,000 tons of oil, and the steam supply accounts for one-third of the total amount of Paris heating companies. Since the 1980s, the United States has * * Invest US$7 billion to build 90 incineration plants with a total annual processing capacity of 30 million tons. At present, the largest waste-to-energy power plant has been built in Detroit, with a daily waste processing capacity of 4,000 tons and a power generation capacity of 65MWe. Sweden, Denmark and other countries also have similar incineration power plants. 2． Foreign waste incineration equipment, waste boilers, are the main equipment of waste thermal power stations and are also the key to the development of waste thermal power stations. Since garbage fuel is garbage with certain corrosiveness, high water content, and unstable calorific value, the design of garbage boilers and their combustion equipment has certain special features. Since garbage has a low calorific value and a high moisture content, combustion equipment with excellent performance is the key to a garbage boiler. The combustion methods of garbage boilers that have been put into operation abroad mainly include the following:: : (1) Multi-stage ladder chain grate garbage flows step by step from high to low on the grate, and burns step by step until it is burned out. (2) The inclined reciprocating grate is a counter-inclined reciprocating grate with intermittent action, which is different from the forward-inclined reciprocating grate with intermittent action in my country. The advantages of this grate are: ①The tinder mixes well with the main garbage, dries easily and catches fire quickly. ②Stir the garbage fully between layers and utilize complete combustion: ③A series of processes such as drying, ignition, combustion and burnout are all carried out on the grate, so the processing efficiency is extremely high. ④ The garbage layer is uniform, the combustion is stable, and the furnace temperature and boiler evaporation change little. (3) Fluidized bed combustion method Fluidized bed combustion has good adaptability to fuels and can completely burn all types of municipal waste or organic industrial waste. (4) Rotary combustion Rotary combustion is a new industrial process successfully tested by KWU/SIEMNS in Uim-Wibligen. This process is an oxygen-free carbonization of garbage at 450°C in a slowly rotating cylinder to produce biogas and solid residues. Non-combustible materials (such as metals, stones, glass, etc.) are removed mechanically from the solid residue, and the remaining part is carbide, with a calorific value similar to that of lignite. This part of carbide is burned together with the generated gas at 1300°C. (5) Plasma arc combustion method This method is to set up a channel in the garbage pile, and input the plasma arc, coolant and gas into the garbage through the channel. At this time, the fire will melt and evaporate the garbage, turning it into harmless glassy slag. The combustion flame temperature can be as high as 8000°C, and the released gas is introduced into the fuel cell to generate electricity. At present, the capacity of foreign waste incineration boilers is generally 10t/h~100t/h, the steam pressure is 1.4Mpa~4.7Mpa, and the steam temperature is mostly saturated and hot, usually at 400. Around C.