abstracts - Институт катализа им. Г.К. Борескова

OP-III-36trickle bed reactor can result in a heating and drying of a part of a porous structure of acatalyst bed, an acceleration of a catalytic reaction because of its transition from a liquidphase to a gaseous phase, hot sport formation and even reactor runaway [4]. To establish thesafety conditions of an operation of such catalytic reactors it is highly desirable to investigateexperimentally the critical phenomena on an individual catalyst pellet as well as in a catalystbed under conditions of occurrence of exothermic reactions and reagent evaporation, inparticularly, the distribution of a liquid phase inside a catalyst pellet/bed under differentconditions of a reactor operation.The visualization of the distribution of a liquid phase inside a catalyst pellet in the courseof AMS hydrogenation has revealed oscillations of the front of a liquid phase propagation intothe pellet and oscillations of a liquid phase content inside the pellet accompanied byoscillations of a pellet temperature [5]. An oscillatory behavior of the catalyst pellet is causedby a heat generation in the course of an exothermic reaction accompanied by the phasetransition. The results obtained indicate that the differences in the rates of heat and masstransfer processes and phase transitions are responsible for the observed oscillatory behaviorof the catalyst pellet and directly demonstrate the existence of a coupling of mass and heattransport and phase transitions with a chemical reaction.The character of the distribution of a liquid phase in the catalyst bed in the course of ahydrogenation reaction under different conditions of a supply of reagents in the trickle bedreactor has been also studied. Ithas been shown that theoccurrence of an exothermicreaction accompanied by thephase transition “liquid-gas”influences essentially thecharacter of the impregnation ofthe porous structure of the bedwith a liquid phase. It has beenrevealed that supply of a liquidFig. 1. Distribution of a liquid phase in the catalyst bed consisting ofreagent to the catalyst bed can the pellets of 4.2 mm in diameter in the course of AMS hydrogenation.a) upper part of the bed; b) lower part of the bed. 1 – the bed was filledlead to the significant gradients with AMS, the liquid AMS supply was 2.65⋅10 -1 g/s, no hydrogen;2-4 – the temperature of a hydrogen flow was 85 С, the rate of Нof the liquid phase content in2 flowwas 20 cm 3 /s, the liquid AMS supply was 2.65⋅10 -1 g/s; 2 – the liquidthe bed because of the AMS supply was turned on to the initially wetted catalyst bed;3, 4 – the liquid AMS supply was turned on to the dry bed.403