Summary
Biochar is elemental carbon residue derived from biomass by pyrolysis or torrefaction.
History
Stub topic - March 2023
(making of charcoal as a better form of cooking fuel than wood - hotter, impervious to rot, light weight, uniform combusion, etc.)
(Amazonian terra preta - indigenous people created fertile soil with charcoal and ceramic debris(?) where infertile rainforest soils otherwise prevailed. This soil has proven to be a durable sequestration and fertile)
Forms and Variations
(primitive: batch charcoal-making - stack biomass, usually wood, and ignite it in an earthen pit. Once the fire is hot, cover it with soil to block further oxygenation and the residual heat drives the decomposition pyrolysis of the wood to charcoal.)
(more sophisticated: burn biomass in an engineered furnace with features that allow oxygen to be blocked by the operator after a degree of combustion has occurred)
(more sophisticated: heat biomass in the absence of oxygen using an external heat source. The decomposition gases are captured and either are burned to supplement the external heat source or collected as products for some other process or use. Heating may be by direct contact with gas or the walls of a channel or pipe, or by contact with molten salt)
{other CDR approaches related to biochar}
Biochar as a concrete additive
Notable Projects
{detailed description of exemplar project(s): TLUD stoves and ROCC kilns - top-fired burning; about 70% of fuel energy of wood can be harnessed without combustion of the charcoal. The combustion heat from burning the non-charcoal biomass is essential for driving the pyrolysis in these units. }
OpenAir Missions:
Unfracking - injecting biochar into old fossil fuel wells to cap them and sequester the carbon
Nakivale - making biochar for agriculture
{policy issues and initiatives related to biochar}
Further Learning
This Is CDR E03 - Introduction to Biochar
This Is CDR E20 - Mote: Carbon-negative H2 from wood
This Is CDR E28 - Future Forest Co forestry management and sequestration with biochar and ERW
This Is CDR E32 - Takachar mobile thermal biomass treatment
{universities and companies engaged in biochar projects}
{literature and conferences related to biochar}
Carbon180 biochar factsheet
Lifecycle assessment of biochar
{foundations, trusts, and agencies funding biochar-related projects}
Effects of biochar addition to soils for plant growth