Biochar – Unfolding New Chapters of Sustainable Energy
Written by: Tuba Yasmin, Md. Mahadi Hasan
Biochar, a modern approach to carbon sequestration to enable negative carbon
emissions also produce oil and gas by-products that can be used as fuel. However, the co-production of biochar and bioenergy can help to mitigate global climate change by substituting fossil fuel consumption and sequestering carbon-instable soil carbon reservoirs. As a result, we can cut carbon emissions by utilizing this simple and effective technique.
Biochar is a charcoal-like substance also known as black carbon as it is a carbon-rich organic substance, and a byproduct generated from burning biomass or organic waste such as grass, rice husk, wood, rice straw, wheat straw, cow manure, crop residues, etc. by the pyrolysis process.
Pyrolysis is a process that involves the heating of biomass in the total or partial absence of
oxygen. Although Biochar might look like charcoal, it is produced using a thermal
decomposition procedure to retain carbon, making biochar unique from regular charcoal. That is why biochar is significantly more effective than other types of charcoal at converting carbon into a stable form.
During pyrolysis, organic materials such as wood chips, leaf litter, or dead plants are burnt in a container with extremely little oxygen. As the materials burn, they emit little to no polluting emissions. The organic material is converted into biochar, a stable form of carbon that cannot easily escape into the atmosphere, during the pyrolysis process. The energy or heat produced during pyrolysis may be collected and used as a clean and renewable energy source. Biochar technology eventually decreases carbon dioxide in the environment by heating the biomass and converting its carbon content into a stable structure that doesn’t react with oxygen. So, it can use used as a possible alternative to burning fossil fuels.
Along with retaining carbon on the surface, the carbon-enriched material (Biochar) also aids in reducing the leaching of soil nutrients into groundwater promotes the retention of nutrients like phosphorus and nitrogen in the soils, and helps protect the nutrients from erosion due to surface water flow and increase soil fertility thus improving crop productivity. The availability of nutrients for crop cultivation rises when nitrogen loss in the soil is controlled, decreasing the quantity of fertilizer needed for crop development. Biochar can be produced at a cheap cost using the pyrolysis process in an eco-friendly manner. It has the potential to produce renewable energy. While biochar may appear to be a simple substance, it has the potential to address several global issues concurrently. The material is capable of seizing a billion tons of carbon each year, that too for thousands of years. As it reduces carbon emissions and controls the release of methane and nitrogen dioxide into the atmosphere, it can help mitigate global warming and sustainable farming.
This biochar experiment takes place in Kanihati, located at the Hajipur union of Moulvibazar district, Sylhet, Bangladesh. It is part of a Farmer Driven Research Project on account of climate-smart regenerative agriculture collaborated with Dr. Abed Chaudhury. This initiative of making biochar was taken by Md. Mahadi Hasan and Tuba Yasmin. The training was given to the lead farmer of this project Md. Rasel Mia.
This experiment is conducted with double barrel retort with pyrolysis which is given to
the farmers at a reasonable price. The raw materials for biochar production are most likely available nearby. The making process takes around 4-5 hours. It is easy and convenient
for farmers to make at their homes.
Biochar was produced with simple equipment. All it takes is two barrels (the outer barrel is
bigger than the inner barrel) and organic biomass is needed to manufacture Biochar. Two holes were made in the lower part of the outer barrel to allow aeration. Then organic biomass such as rice straw, mustard biomass, dried leaves, twigs, wood chips, and crop residues was taken in the inner barrel. Then the inner barrel turned over and was placed in the outer barrel to prevent oxygen flow into the inner barrel. After that, a fire was set between the barrels to continue pyrolysis. It took around three hours to finish the process. After cooling down, the inner barrel was
flipped up to collect the biochar, and it was ground and stored for further use.