Question

what will happen if carbonisation happens with oxygen in it

Answer 1

In torrefaction, the biomass is slowly heated to 200–300°C without or little contact with oxygen. This process alters the chemical structure of biomass hydrocarbon to increase its carbon content while reducing its oxygen. Torrefaction also increases the energy density of the biomass and makes the biomass hygroscopic

Answer 2

Carbonisation is the term used when complex carbonaceous substances such as wood or agricultural residues are broken down by heating into elemental carbon and chemical compounds which may also contain some carbon in their chemical structure.