Interpretation of Garbage Pyrolysis Furnace Technology

With the rapid development of urban construction and new rural construction in China, the output of domestic waste is increasing daily. This is particularly evident in the centralized treatment of rural and township waste within the urban solid waste management system, which consumes extensive transfer equipment and transportation costs and often leads to secondary pollution during operation. Therefore, decentralized on-site treatment of township and rural waste has emerged as a viable solution.

Currently, some township waste is treated through simple on-site landfill and incineration methods, which are neither environmentally friendly nor efficient in land resource utilization. The use of a garbage pyrolysis furnace to process waste aligns more closely with the principles of energy recycling, focusing on reduction, harmlessness, and resource utilization. This technology employs a high-temperature pyrolysis gasification furnace combined with a secondary combustion chamber and an energy utilization system, which has received positive feedback in various projects nationwide. The patented furnace structure and secondary combustion chamber technologies enhance equipment efficiency and control pollution at its source. In the secondary combustion chamber, pyrolysis gas can be completely and stably burned at temperatures exceeding 1300℃, effectively cracking pollutants at high temperatures. This method of pyrolysis and secondary combustion does not require any additional fuel or energy, achieving environmentally friendly and stable energy utilization.

Principles of Pyrolysis and Gasification

Garbage pyrolysis and gasification refer to the process where the macromolecules of organic components in waste break down under oxygen-free or low-oxygen conditions, generating small molecular gases, tars, and residues. This technology not only achieves harmlessness, reduction, and resource utilization of waste but also effectively addresses the dioxin pollution problems associated with waste incineration.

Stages of Pyrolysis and Gasification

The process can be divided into two main stages:

• Primary Reaction Stage: Under heating conditions, combustible solid waste undergoes a cracking process, resulting in the release of volatile matter, tars, methane, and other gaseous products. This stage primarily accounts for the initial weight loss.
• Secondary Reaction Stage: As temperatures rise, macromolecular substances are further cracked to produce complex gases, including methane and other gases. This stage consists of small molecular secondary reactions and macromolecular secondary reactions leading to the formation of small molecular substances such as methane, benzene, and carbon.

The ash produced from this pyrolysis gasification equipment can be disposed of via landfill with low energy consumption and without the need for additional fuel. The flue gas and wastewater emissions comply with national standards.

Garbage Stratification in Pyrolysis Plants

Within a pyrolysis plant, the garbage is stratified into four layers from top to bottom:

• Drying Layer: Located at the top of the furnace, flue gas is extracted to enhance the material drying process.
• Pyrolysis Gasification Layer: Dried garbage absorbs heat from the red charcoal layer, producing hydrocarbon combustible gases like H2, CO, CH4, and C2H6.
• Red Charcoal Layer: Maintaining a stable environment, this layer ensures sufficient heat for the layers above while keeping the temperature around 600℃.
• Ash Layer: After full combustion in the red charcoal layer, ash is formed, which may be used as roadbed filler or disposed of through fixed-point landfill following harmless treatment.

Advantages of Pyrolysis Gasification Technology

Compared to direct incineration, pyrolysis gasification technology offers several advantages:

• It converts organic waste components into various usable energy forms, including combustible gas and tar, making it more economical.
• The low air coefficient during gasification significantly reduces smoke exhaust volume, enhances energy utilization, and minimizes nitrogen oxide emissions, thereby reducing both investment and operating costs for flue gas treatment.
• In a reducing atmosphere, metals remain unoxidized, facilitating efficient recycling while minimizing catalysts that promote dioxin formation.
• The flue gas generated through pyrolysis gasification has fewer pollutants, including heavy metals and dioxins, thereby reducing secondary pollution and simplifying environmental control measures.