Biomass fuel molding equipment

Due to the high mixing and heterogeneity of household waste and other solid waste, using a forklift to grab materials aims to mix household waste evenly, facilitate the removal of large items inside, and facilitate the storage of materials and the precipitation of moisture.

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.

Traditional household waste pyrolysis

Traditional household waste pyrolysis is high-temperature pyrolysis, which produces combustible gases and ash from waste under thermal conditions of partial carbon combustion and partial carbon reduction.

The traditional pyrolysis of household waste produces combustible gases mainly through the oxidation-reduction and cracking reactions of the waste raw materials. Oxidation reaction: It is a combustion reaction between a portion of carbon in garbage and air, generating a large amount of carbon dioxide and releasing heat at a temperature of up to 1000-1300 ℃. This heat provides a heat source for reduction and cracking reactions.

Reduction reaction: Carbon dioxide and residual carbon generated in the oxide layer undergo a reduction reaction with water vapor, producing carbon monoxide and hydrogen gas.

Cracking reaction: At a temperature of 225-500 ℃, combustible gases, carbon, tar, and water vapor are released.

The combustible gases produced by traditional household waste pyrolysis are carbon monoxide (15-20%), nitrogen (about 50%), and volatile gases (only 30-35%), so their calorific value is relatively low. The calorific value of combustible gas per cubic meter of waste is about 1000 kcal, and about 3 cubic meters of gas can be generated per kilogram of waste; Due to the complete consumption of charcoal, only residual ash remains (some municipal solid waste pyrolysis furnaces advertise that they also produce charcoal, but this is also because the slag discharge is too fast, and the charcoal is not completely burned out. If there is charcoal, it is not good charcoal). At present, the thermal decomposition performance of small traditional household waste in China is extremely unstable and cannot be widely applied, while the thermal decomposition of large traditional household waste has extremely unsafe factors and is trapped by ash, floating ash, and tar.

Principle of Thermal Cracking of Low Temperature and Oxygen in Household Waste

Thermal cracking of household waste with low or no oxygen content is the process of producing combustible gases, charcoal, wood vinegar, and tar from the waste under thermal conditions that isolate oxygen.

The process of producing combustible gases during the thermal cracking of municipal solid waste is only a part of the cracking reaction in the thermal cracking furnace. The carbon in the waste does not participate in the reaction, as long as it can provide a cracking reaction temperature of 225-600 ℃. The reaction mechanism is as follows: hemicellulose mainly precipitates volatile components at 225-350 ℃; Cellulose mainly releases volatile components at 325-375 ℃; Lignin releases volatile components at 250-570 ℃,

The combustible gas produced by the thermal cracking of household waste with low temperature and oxygen content is mainly volatile gas, so its calorific value is relatively high. The calorific value of combustible gas per cubic meter of garbage is about 2000 kcal, and about 1.5 cubic meters of combustible gas can be produced per kilogram of garbage; The ash content of charcoal is very low, and its calorific value is generally around 8000 kcal/kg. It has a wide range of uses and a high price; The quality of wood vinegar and tar is also good. A reasonable garbage pyrolysis furnace has stable performance and good safety.