Biochar production involves various reactor configurations, each with its own advantages and limitations. The choice of reactor depends on several factors, including the desired product qualities and production efficiency.
Which Reactor Configuration is Preferred in Biochar Production? (4 Key Factors to Consider)
1. Fixed Bed Pyrolysis Reactors
For simple biochar production, fixed bed pyrolysis reactors are commonly used. These include pit kilns, mound kilns, brick kilns, transportable metal kilns, Missouri-type charcoal kilns, and continual multiple hearth kilns.
These reactors operate without air supply, which reduces CO₂ emissions and energy loss from the feedstock. This results in energy-rich products like biochar and bio-gas.
The energy needed to maintain temperatures in these reactors can be provided by burning the gaseous reaction products.
Approximately 25-35% of the yields from these reactors are biochar.
2. Slow Pyrolysis for High-Quality Biochars
To produce high-quality biochars suitable for agricultural use, slow pyrolysis is often the best option. This process involves heating biomass in an oxygen-limited or oxygen-free environment at atmospheric pressure.
Typical heating rates range from 1 to 30 °C per minute. The process heat is usually supplied from an external source, such as the combustion of produced gases or partial combustion of the biomass feedstock.
Biochar yields from slow pyrolysis are usually up to 30% on a dry feedstock weight basis. The yield and properties of the biochar depend on factors like the biomass feedstock, heating rate, pyrolysis temperature, and vapor residence time.
The highest treatment temperature (HTT) in the pyrolysis reactor has the greatest influence on the final product characteristics.
3. Batchwise Treatment of Biomass Feedstock
Another method involves batchwise treatment of the biomass feedstock, where the heat required for pyrolysis is generated by burning part of the biomass with air admission. This method is commonly used in charcoal kilns and provides slow pyrolysis.
It is mainly useful for charcoal production, although tar can also be obtained as a by-product.
4. Industrial Production Using Inert Combustion Gases
For industrial-scale production, the feedstock is heated by inert combustion gases in the complete absence of oxygen. This method allows for continuous processes with high capacities, achieving efficiencies of over 30% by weight.
Pyrolysis is initiated by burning fuel oil, but once combustible gases are released from the biomass, they are burned instead of the oil. This continuous process enables careful control of emissions.
5. Fluidized Bed Combustor (FBC) Using Inert Solid Material
The third method uses inert solid material, such as sand in a Fluidized Bed Combustor (FBC), as an energy carrier to heat the biomass during pyrolysis. This method is suitable for fast heating of the biomass, particularly when the yields of gas or liquid products are the main focus.
Continue exploring, consult our experts
Are you in need of a reliable and efficient fixed bed pyrolysis reactor for biochar production? Look no further than KINTEK! Our reactors, including pit kilns, mound kilns, brick kilns, and more, are designed to operate without air supply, resulting in minimal CO₂ and energy release. With slow pyrolysis at atmospheric pressure, we can help you produce high-quality biochar for agricultural use. Trust KINTEK for all your biochar production needs. Contact us today to learn more!
