Structural optimization of baffle internals for fast particle pyrolysis in a downer reactor using the discrete element method

Abstract

Abstract The structural optimization of baffle internals for fast pyrolysis of coal with particulate mixing and heat transfer in a downer reactor using the discrete element method (DEM) has been investigated in this research. The pyrolysis terminal temperature at the exit of the downer reactor is not only decided by the volume-feeding-rate ratio of the coal to the sand, but also is affected by the inner structural design of the baffle internals in the downer reactor. As presented in the previous publication of the author, the inhibition from the baffle internals in a downer reactor can improve the particulate-mixing degree and heat carrier, and increase the mean residence time of the coal and heat-carrier particles in the downer reactor. The structure of the baffle internals in the downer reactor mentioned in this research can be optimized by the independently developed 3D soft-sphere model of the DEM programme of a 40-mm baffle length, a 30° baffle-slope angle and at least four baffles designed in the downer reactor, which is beneficial for the process design of coal pyrolysis with a heat carrier in the downer reactor.