Pyrolysis can lead to less carbon emissions

Burning one ton of wood pellets emits 357 kilograms less carbon than burning coal with the same energy content. But turning those wood pellets into char would save 372 kilograms of carbon emissions. That is because 300 kilograms of carbon could be buried as char, and the burning of byproducts would produce 72 kilograms less carbon emissions than burning an equivalent amount of coal. This is a calculation presented in a paper by Malcolm Fowles of the Open University, United Kingdom. Such an approach could carry an extra benefit. Burying char, known as black carbon sequestration, enhances soils helping future crops and trees grow even faster, thus absorbing more carbon dioxide in the future. Researchers believe that the char, an inert and highly porous material, plays a key role in helping soil retain water and nutrients, and in sustaining microorganisms that maintain soil fertility and has significant and long-lasting positive effects on soil fertility. Pyrolysis process initiates on materials like wood and other biomass at around 230C and during pyrolysis thermally unstable components such as lignine in biomass are broken down and evaporate with other volatile components. The resulting pyrolysis gas consist mainly of tar, polycyclic aromatic hydrocarbons (PAH), methane (CH4), steam and CO2. The solid residual is carbon structures (coke) and ashes. Pyrolysis can play to offset greenhouse-gas emissions. Bioenergy through pyrolysis which gives bio oil in combination with biochar sequestration is a technology to obtain energy and improve the environment in multiple ways at the same time.