ENERGY BALANCES FOR THREE-PHASE REACTORS

we will consider reactors operating in a concurrent mode. Provided that the gas, the liquid, and the solid catalysts have the same temperature, the energy balance for a volume element, AVr, that includes the catalyst mass, Arwcat, can be written as 

The term R(—AHr)AnicM defines the amount of heat released or consumed in an exothermic or endothermic reaction, respectively. This energy effect induces changes in the temperatures of the gas and Kquid flows. The change in temperature is described by the terms Cpiihi AT and CpLtWG AT. The heat transfer from or to the surroundings is given by AQ. 

Equation 6.48 is valid for a system with a single reaction. The definition for the catalyst bulk density pb. Equation 6.7, implies that 

Heat transfer from or to the surroundings is typically described by 

If the ratio heat transfer area-to-volume of the reactor is constant (AS/AVr = S/Vr) and AVr 0 in Equation 6.51, the energy balance is transformed to 

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