Industrial solid waste pyrolysis furnace

The technical measure of heating solid waste under anaerobic or hypoxic conditions to decompose it and convert it into storable and easily transportable energy sources such as gas fuel and fuel oil, or to recover resource-based products (such as pyrolysis liquid products as chemical raw materials). Due to the fact that pyrolysis is carried out under anaerobic or hypoxic conditions, its exhaust volume is smaller than incineration. Mainly used for the treatment and utilization of urban household waste, sludge, waste plastics, waste rubber and other waste.

Household waste belongs to biomass waste, and the volatile matter in household waste is particularly high, accounting for about 70% of the calorific value, while coal is relatively low, with anthracite accounting for less than 10%. Volatile matter is mainly composed of high calorific value hydrogen, oxygen, methane, and hydrocarbons. Coal mainly generates heat during combustion, while household waste releases a large amount of volatile matter at 225-500 ℃ during combustion. It is difficult to completely burn it with a single gas supply, so household waste is not suitable for direct combustion. The way to burn household waste is to use medium temperature and oxygen deficient pyrolysis to extract the volatile components from the waste and convert them into biomass combustible gas, which can be burned like natural gas. That is to say, household waste is a good raw material for producing combustible gases.

Compared with traditional pyrolysis of household waste, thermal cracking with low temperature and oxygen in household waste can produce combustible gases, but there is a qualitative difference.

In traditional waste incineration, the direct combustion method is prone to produce dioxins, which require four basic conditions for their formation: chlorine, oxygen, lower temperature, and catalyst; There are two conditions for the formation of dioxins: low-temperature production inside the furnace and synthesis of flue gas outside the furnace. Chlorine elements such as plastics in garbage are more likely to produce dioxins at temperatures of 250-350 ℃ and increase with the increase of oxygen concentration. Organic or inorganic chlorine gas in flue gas fly ash and catalysts (copper, iron and other oxides) catalyze the synthesis of dioxins. Therefore, the standard GB 18485-2014 for pollution control of municipal solid waste incineration requires the furnace temperature to be ≥ 850 ℃, and requires a sharp decrease in flue gas temperature and a reduction in copper, iron and other oxides in the waste.

Traditional waste incineration is a direct oxygen enriched incineration method, which involves burning waste in a furnace at around 1000 ℃ without any hierarchical oxygen enriched flames. Although dioxins are cracked at high temperatures, they are also regenerated into dioxins during the flue gas emission process under the catalytic action of HCL and CuCL2 elements. Moreover, smoke and dust are directly emitted into the environment, polluting the environment and often causing mass incidents.

The low-temperature and oxygen deficient pyrolysis device for municipal solid waste in urban communities and residential areas is the opposite of direct incineration. It uses anaerobic or extremely low oxygen pyrolysis without open flame combustion. Under low-temperature and oxygen deficient conditions, dioxins cannot be synthesized (eliminating the synthesis conditions of dioxins), and copper, aluminum, iron metals, etc. in the waste are not easily oxidized under low-temperature and oxygen deficient conditions, making it difficult to produce dioxins as catalysts.

Thermal decomposition of municipal solid waste in urban communities and residential areas is the process of producing combustible gases and charcoal from the waste under thermal conditions that isolate oxygen or have little oxygen, without emitting dust or harmful gases.