Based on the theories of lubrication approximations and Nusselt liquid film flowing,a model describing close contact melting of phase change solid around a hot sphere is developed by applying a more stringent energy balance relation at the two phase interface.

Based on characteristics of heavy oil contact cracking(HCC) process, analytical compositions of structural groups,as well as cracking performance of different feedstocks,a sixteen lumped kinetic reaction network and its corr e spondent mathematical model were established for HCC process.