energy Balance
Unlike combustion reactions, most gasification reactions are endothermic.
Thus, heat must be supplied to the gasifier for these reactions to take place at
the designed temperature. In laboratory units, this is not an issue because the
heat is generally supplied externally. In commercial units, it is a major issue,
and it must be calculated and provided for. The amount of external heat supplied to the gasifier depends on the heat requirement of the endothermic reactions as well as on the gasification temperature. The latter is a design choice,
and it is discussed next.