There are many issues that need to be paid attention to during the bio charcoal production process. Bio charcoal production projects involve many key links, including raw material selection, production process control, product quality, safety and environmental protection.
Raw Material Selection and Pretreatment
Raw materials fundamentally determine the properties and uses of biochar.
Raw materials of biochar production can include agricultural waste (straw, rice husks, fruit shells), forestry waste (wood chips, branches), organic household waste, and sewage sludge. Different raw materials have varying ash, volatile matter, and fixed carbon contents, which directly affect charcoal yield and quality.
The moisture content of the raw materials is crucial. Excessive moisture consumes significant energy for evaporation, reducing pyrolysis efficiency. This increases production costs and may affect biochar quality.
Raw material pretreatment involves crushing and pulverizing the raw materials into uniformly sized particles. This ensures a uniform pyrolysis process, avoiding overburning or incomplete carbonization, and improving product quality consistency.
Bio Charcoal Production Process Control
This is the core of bio charcoal production and directly determines the properties of the product.
Pyrolysis Temperature
Pyrolysis temperature is the most critical process parameter. The temperature range is typically between 350°C and 700°C. Biochar produced at low temperatures (<500°C) typically has more functional groups and higher yields, but also has a smaller surface area. Biochar produced at high temperatures (>600°C) has a larger surface area, more developed pores, and stronger alkalinity, but also has a lower yield.
Application Guidelines: The temperature selection depends on the biochar application. For example, moderate temperatures may be preferred for soil improvement and carbon sequestration. High-temperature carbon may be required for pollutant adsorption or as a catalyst support.
Heating Rate and Residence Time
Slow pyrolysis involves a slow heating rate (typically <10°C/min) and a long residence time (on the order of hours). This is the mainstream method for bio charcoal production and maximizes solid biochar yield.
Fast pyrolysis involves extremely rapid heating rates (100-1000°C/s) and a short residence time (on the order of seconds). The primary goal is to produce bio-oil, with biochar as a byproduct.
Excessively long residence times or high temperatures can lead to "graphitization" of the biochar, reducing its reactivity and making it unsuitable for certain applications.
Oxygen Control
Biomass pyrolysis, the production of bio charcoal, must be carried out under oxygen-deficient or anaerobic conditions. If oxygen is present, combustion will occur, producing ash instead of biochar.
Safety and Environmental Issues
The bio charcoal production process must ensure operator safety and environmental protection.
The pyrolysis process produces a large amount of combustible synthesis gas (syngas), including carbon monoxide (CO), methane (CH4), and hydrogen (H2). This syngas must be properly handled.
Flue gas and pollutants must not be discharged directly. Flue gas should be treated through secondary combustion or a purification system to meet environmental requirements and prevent air pollution. Even oxygen-limited pyrolysis produces flue gas, which may contain harmful substances such as tar, dust, and small amounts of polycyclic aromatic hydrocarbons (PAHs).
The bio charcoal production site should be away from flammable materials and equipped with fire-fighting equipment. Operators must receive training and understand the equipment's operating procedures and safety risks (such as high temperatures, toxic gases, and fire).
Continuous Pyrolysis Plant for Biochar Production
Careful selection of appropriate biomass pyrolysis equipment is crucial during biochar production. The selection of biochar production equipment directly impacts production efficiency, product quality, and production costs.
Mingjie Biomass Carbonization Plant uses continuous pyrolysis technology to achieve continuous production of biochar, improving production efficiency. We also provide advanced tail gas treatment systems and heat recovery systems, which can effectively treat waste gas and recover energy.
