The Effect of Thermo-physical Properties of Catalyst on the Hot Spots Region in the Multi-Tube FBCR

In this paper, the effect of catalyst thermo-physical properties on the hot spots region is investigated in the multi-tube FBCRs. The hot spots region can cause damage to both catalyst (via sintering) and reactor vessel (via thermal stresses). Process selectivity may also deteriorate through the initiation of undesired side chemical reactions. For this purpose a heterogeneous model is used essentially. Hot spots region is determined by two dimensional heat and mass conservation PDEs. Galerkin finite element method is used for solving coupled PDEs. The effects of external surface area and thermal conductivity of catalyst are investigated and their impacts on the development of hot spots in reactor are analyzed. Under typical process conditions the modeling results show the hot spot region is close to downstream of reactor inlet. The hot spots location alteration were depicted in graphs. Also the difference between the maximum gas phase temperatures and catalyst temperature is very high at the low surface areas. The hot spots cool down with increasing the thermal conductivity of the catalyst.