Model development of UCG and calorific value maintenance via sliding mode control

The design of underground coal gasification (UCG) process is a difficult task, especially if its performance needs to be compared with surface gasification, because in UCG there is a lack of direct control to many important parameters. In this work a nonlinear time domain model of UCG is formulated by incorporating some assumptions in already existing models of [1] and [2]. The input of the model is molar flow rate of inlet gas (mixture of Air and steam), and output is the calorific value of exit gas. In order to keep the calorific value at a desired value in the presence of external disturbance, the model is used in a closed loop configuration with a sliding mode controller (SMC).