In order to maintain isothermal bed conditions, the temperature of the bed was maintained
below 750 °C; under these temperature conditions the gasifier was operated at ERs from 0.1
to 0.27. Equilibrium modelling showed that the gasifier was operating at suboptimal ERs:
the maximum calculated theoretical CGE of 73% was obtained at an ER of 0.35.
The maximum LHV of the producer gas was approximately 3.6 MJ m-3 and was obtained at
an ER of 0.165, well below the modelled ER to obtain maximum CGE. It was observed that,
despite fluctuations, a producer gas with an LHV of approximately 3 MJm-3
at STP could be
obtained across the range of ERs. Considering the LHV obtained, and taking fluctuations in
LHV into account as well as the reported tar content for fluidised bed gasifiers, it is
suggested that the optimal use for the producer gas is in heat applications