Catalytic effects runaway reactions

Agnew and Potter [6] did the same as Barkelew for heterogeneous catalytic reactors and presented design diagrams to prevent runaway, including also the parameter of the ratio of the tube to the catalyst particle diameters dt/dp. Burghardt and Warmuzinski [7] considered multiple reactions and also took the heat effect of the secondary reaction into account however, they did not study the selectivities achieved in the reactor. 

As the catalytic reaction taking place inside the pellets is usually accompanied by heat effects, the particle-liquid heat transfer coefficient becomes a fundamental ingredient to be estimated for the assessment of the efficacy of the heat withdrawal from the particle level away to the reactor wall leveL In particular, when highly exothermic reactions are in play, impediment of liquid replenishment over the dried spots on the catalyst surface may favor inception of hot spots that are responsible for reactor runaway. As a result, evacuation of heat across the liquid-covered pellet spots becomes a critical issue. Not many studies in literature deal with particle-liquid heat transfer rates in three-phase fixed-bed reactors. The main reason is probably the difficulty to find an accurate experimental method. The following current trends emanate from the analysis of the particle-liquid heat transfer two-phase downflow fixed-bed literature (i) the transition from trickle to pulsing flow is accompanied by a... 

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