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Biochar, a charcoal produced from biomass, can sequester carbon in soil for hundreds to thousands of years. Pre-Columbian Amazonian Indians used it to enhance soil productivity, and it is still found in large concentrations in Amazon soils abandoned thousands of years ago. Its modern equivalent is produced by pyrolysis, the direct thermal decomposition of biomass in the absence of oxygen to an array of solid (biochar), liquid (bio-oil) and gas (syngas) products. The specific yield from pyrolysis depends on process conditions, and can be optimized to produce either energy or biochar. Being an exothermic process, biochar production produces 3-9 times more energy than is invested, and is carbon-negative (withdraws CO2 from the atmosphere). In addition, modest additions of biochar to soil have been found to reduce NOx emissions by up to 80% and to completely suppress methane emissions, thus directly reducing agricultural greenhouse gas emissions. While some fresh organic matter is needed by agricultural soil to maintain its productivity, much agricultural waste (and other kinds of waste streams) can be turned directly into biochar, bio-oil, and syngas.
In addition to its potential for carbon sequestration and decreased greenhouse gas emissions from agriculture, biochar is reported to have numerous benefits as a soil amendment: increased plant growth yield, improved water quality, reduced leaching of nutrients, reduced soil acidity, increased water retention, and reduced irrigation and fertilizer requirements. The quality of biochar as a soil ameliorant depends on the character of the biochar and on regional conditions including soil type and condition (depleted or healthy), temperature, and humidity.
Estimates for biochar residence time in soil range from 100 to 10,000 years, with 5,000 years being a common estimate. Whilst the means by which biochar mineralizes are not completely known, it is apparent that mineralization rates depend on the feedstock material, the extent of charring, the surface:volume ratio of the particles, and the soil environment. Lab experiments confirm a decrease in carbon mineralization with increasing pyrolysis temperature, so careful control over the charring process can increase the soil residence time of the biochar C.
Bio-oil created in the pyrolysis process can be used as a replacement for numerous applications where fuel oil is used, as well as a feedstock for chemical production. Syngas and bio-oil can also be “upgraded” to transportation fuels like biodiesel and gasoline substitutes. If biochar is used for the production of energy rather than as a soil amendment, it can be directly substituted for any application that uses coal. Syngas can be burned directly, used as a fuel for gas engines and gas turbines, or used in the production of methanol and hydrogen.

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Biochar for 21 st century challenges: Carbon sink, energy source and soil conditioner
Biochar for 21 st century challenges: Carbon sink, energy source and soil conditioner

Biochar, a charcoal produced from biomass, can sequester carbon in soil for hundreds to thousands of years. Pre-Columbian Amazonian Indians used it to enhance soil productivity, and it is still found in large concentrations in Amazon soils abandoned thousands of years ago. Its modern equivalent is produced by pyrolysis, the direct thermal decomposition of biomass in the absence of oxygen to an array of solid (biochar), liquid (bio-oil) and gas (syngas) products. The specific yield from pyrolysis depends on process conditions, and can be optimized to produce either energy or biochar. Being an exothermic process, biochar production produces 3-9 times more energy than is invested, and is carbon-negative (withdraws CO2 from the atmosphere). In addition, modest additions of biochar to soil have been found to reduce NOx emissions by up to 80% and to completely suppress methane emissions, thus directly reducing agricultural greenhouse gas emissions. While some fresh organic matter is needed by agricultural soil to maintain its productivity, much agricultural waste (and other kinds of waste streams) can be turned directly into biochar, bio-oil, and syngas.
In addition to its potential for carbon sequestration and decreased greenhouse gas emissions from agriculture, biochar is reported to have numerous benefits as a soil amendment: increased plant growth yield, improved water quality, reduced leaching of nutrients, reduced soil acidity, increased water retention, and reduced irrigation and fertilizer requirements. The quality of biochar as a soil ameliorant depends on the character of the biochar and on regional conditions including soil type and condition (depleted or healthy), temperature, and humidity.
Estimates for biochar residence time in soil range from 100 to 10,000 years, with 5,000 years being a common estimate. Whilst the means by which biochar mineralizes are not completely known, it is apparent that mineralization rates depend on the feedstock material, the extent of charring, the surface:volume ratio of the particles, and the soil environment. Lab experiments confirm a decrease in carbon mineralization with increasing pyrolysis temperature, so careful control over the charring process can increase the soil residence time of the biochar C.
Bio-oil created in the pyrolysis process can be used as a replacement for numerous applications where fuel oil is used, as well as a feedstock for chemical production. Syngas and bio-oil can also be “upgraded” to transportation fuels like biodiesel and gasoline substitutes. If biochar is used for the production of energy rather than as a soil amendment, it can be directly substituted for any application that uses coal. Syngas can be burned directly, used as a fuel for gas engines and gas turbines, or used in the production of methanol and hydrogen.

Scientific Publication