Based on the balance equations of mass, partial mass,
momentum and thermal energy, the pyrolysis process
of non-coking coals using a counter-rotating twin screw
reactor (TSR) is modelled by means of commercial CFD
code PhoenicsTM. In favour of good convergence of the
mathematical solution, a structured, cylindrical-polar grid
is chosen. Variable filling and intermeshing degrees are
taken into account by blocking numerical cells in gas
domain and intermeshing domain instead of performing
two-phase calculations in a body-fitted co-ordinate system.
Viscous behaviour of the granular coals is expressed by
means of a generalised Newtonian fluid and chemical
decomposition is implemented with aid of distributed
activation energies.