Waste pyrolysis and gasification technology is called the third generation of waste treatment technology. The first two generations of technology are waste sanitary landfill and waste incineration. Waste pyrolysis and gasification is the process of heating and decomposing organic combustibles in the absence of oxygen or lack of oxygen. This process is a complex chemical reaction process, including the scission of macromolecular chains and the polymerization of small molecules. In this process, steam, free oxygen and carbon in the fuel undergo a thermochemical reaction to produce combustible gas.
Waste gasification technologies have been commercialized for decades in developed countries such as Europe, America, Japan and South Korea. Especially in Japan, most waste treatment plants use a combination of waste pyrolysis gasification and plasma melting. my country has also explored and practiced waste gasification technologies for more than ten years, and has been successfully commercialized. The waste pyrolysis gasification technology can effectively solve the problem of tail gas pollution and fly ash pollution caused by waste incineration while realizing the harmlessness, reduction and recycling of waste, so it is called the third generation technology of waste treatment.
With the development of this technology, several different types of pyrolysis and gasification technologies have also been developed in the market, which can be divided into: fixed bed waste pyrolysis and gasification technology, fluidized bed waste pyrolysis and gasification technology technology, mainstream cracking gasification technology.
Fixed bed pyrolysis gasifier is also called fixed grate pyrolysis gasifier. As the name implies, this type of furnace body has a fixed position grate. The garbage is piled up and burned on a fixed road sign and reacts in an oxygen-deficient environment. Produce combustible gas while disposing of waste. This type of equipment has strong adaptability to fuel, the garbage is simply crushed, and it can be processed by preliminary screening. According to the different gas outlet positions, fixed bed pyrolysis gasifiers can be divided into upper suction, horizontal suction and downward suction fixed bed pyrolysis gasifiers. At present, the above suction fixed bed pyrolysis gasifier is the mainstream technology on the market.
The fluidized bed waste pyrolysis gasifier gasifies the waste while the waste is flowing, that is, the waste enters the main furnace of the gasifier and is blown up by the bottom wind, and is fluidized and gasified in the furnace. This type of gasifier has a small furnace body, a fast reaction speed and a large processing capacity, but the requirements for garbage are relatively high, and the garbage needs to be finely sorted and crushed. Not suitable for regions and countries with low waste disposal subsidies.
The waste retorting pyrolysis gasifier is aerobic oxidation, that is, there is no oxygen involved in the reaction. It uses an externally heated closed drum. When the temperature reaches above 400 °C, the waste in the furnace will be carbonized, and the hydrocarbons in the macromolecular chain will be cracked. The gas evolved into small molecular chains. These gases are mainly methane and ethane, which can be used as energy. This type of equipment is mainly used on relatively pure industrial waste, such as rubber (waste tires, etc.), plastics, chemical fibers, etc. The gas generated by such equipment can be cooled and filtered to produce considerable heavy oil, such as waste tires, which can be produced by dry distillation and cracking. 40-45% of tire crude oil, about 15% of steel wire, about 40% of carbon black, the economic benefits are considerable.
The existence of each technology is meaningful. If there is no demand, there will be no corresponding technology. Therefore, the above types of waste pyrolysis and gasification technologies play different roles in different solid waste disposal. In general, fixed bed pyrolysis gasification technology is generally suitable for wastes with complex types and high water content, such as domestic waste; fluidized bed waste pyrolysis gasification furnace is suitable for small particle waste with uniform particle size, and the water content cannot be If it is too high, the subsidy fee for garbage disposal will be high; the dry distillation pyrolysis gasifier is suitable for the disposal of rubber, plastic and other garbage with high oil content, which can produce considerable economic benefits. At present, there are not many R&D and manufacturers in China that can have these types of equipment at the same time. Haiqi Environmental Protection Technology Co., Ltd. is one of them. The company not only has in-depth research on these technologies, but also has landing projects in practice run.