Biochar is a stable form of charcoal and is used to enhance soils, and filtration. Due to the molecular structure biochar is chemically and biologically more stable than the original carbon it comes from.
Biochar is produced by torrefaction of biomass usually through the process of direct or indirect heating. Biochar is also considered a means of sequestering carbon to offset negative carbon dioxide emissions. As an example and thousands of years ago Amazon Indians put charcoal into the soil to enhance its fertility.
Archaeological finds show that a lot of this charcoal still remains fixed in the soil to this day. Evidence also suggests that ancient people piled and covered wood in earthen pits, then burned it slowly with limited air. This method, still used today in developing countries, creates considerable smoke and releases half the carbon dioxide in the original biomass along with other greenhouse gasses. That’s not healthy for people or the atmosphere and all that heat (energy) is wasted.
Biochar is known to increase soil fertility and agricultural productivity whilst providing protection against some soil-borne diseases. Studies have shown that biochar can help: retain nutrients in the soil; decrease soil acidity; decrease the uptake of toxins; improve soil structure; assist in water retention; and decrease the release of CH4 and N2O greenhouse gases. However caution needs to be exercised in terms of how and what is turned into biochar. Here you will find information and plans to build gasifiers to make biochar at a range of scales.
Biochar Gasification Plans
1G Toucan TLUD for Biochar Production, January 2010, Hugh McLaughlin, Alterna Biocarbon Inc. (The lowly 1G Toucan is intended for introducing the user to TLUDs and generating small
quantities of biochar for home use.)
Barrel-size Micro-gasification for Combined Heat and Power, 2012 Paul Anderson, ETHOS conference 2012.
Building SeaChar.org’s Estufa Finca 5 Gallon BioChar Farm Stove, 2012, Donnelly, A., SeaChar.org.
Fabricating a 200L biomass gasifier for making enhanced water filter Biochar, Aqueous Solutions, Advancing Science of Self-reliance.
Fatboy Up Draft Top Lit Gasifier, basic plans
Making Biochar in a15oz TLUD, School Lesson Plan, NASA, US Biochar Initiative
Simple Biochar Production Generated From Cattle Dung and Coconut Shell, 2011 Journal of Basic and Applied Scientific Research, by Sukartono, Utomo, Nugroho and Kusuma.
Also see the Biochar Information page for research papers and further detail