Gasification reactor data, kinetics

Hla, S.S., Harris, D.J., and Roberts, D. (2006) CFD modelling for an entrained flow gasification reactor using measured intrinsic kinetic data. Proceedings of the Fifth International Conference in CFD in the Process Industries. 

Gasification. The only study on gasification kinetics of Texas lignite has been performed by Bass (23). Using a differential reactor, he obtained rate data at 700°C and for pressures ranging from 61.6 to 225.9 kPa. Rate equations as a function of steam partial pressure and carbon conversion were developed. 

Many researchers have tried to correlate the kinetic rates of carbon gasification to the many physical and chemical properties of the different materials used. Despite of this a universal rate expression does not exist. Furthermore it is difficult to find data operational for reactor simulations in the relevant temperature and partial pressure ranges. In particular the variation of the reactivity with conversion due to structural variations is not dealt with, i.e. the structural profile is seldom explicitly given. 

Heterogeneous kinetics of straw pyrolysis and straw gasification are essentia data for reactor design. Pyrolysis is a relatively fast process. In view of the poor heat conduction of straw and straw char, the pyrolysis time is the time which is required to heat the center of the particle to the decomposition temperature. This is a rather simplified model, but allows a reasonable time estimate in view of the order of magnitude. 

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