A process model based on the ASPEN PLUS process simulator has been developed for a novel Compartmented Fluidised Bed Coal Gasifier (CFBCG) process. A distinctive feature of the model is that a number of user-written models have been incorporated within the ASPEN Frame to describe processes of hydrodynamics, coal combustion and gasification, solid circulation, entrainment and elutriation, and particle size distribution in the CFBCG and energy loss to the environment from the reactor. In general, most of the predictions of the model is in a reasonable agreement with the experimental results. However, some unmeasurable operating parameters at hot state in the experiments lead to some difficulties to verify the model in these instances against real data. Uncertainty related to volatile combustion mechanisms in fluidised beds in the literature also influences the model accuracy. Nevertheless the ASPEN based model provides a convenient vehicle for the further development of this new process, by allowing the physical insights into mechanisms, which would be difficult and expensive to investigate experimentally. The simulations indicate that the CFBCG concept is sound and further development is needed to improve the operatibility of the process before practical implementation to produce high quality synthesis gas from the CFBCG might be considered.