MIXING EFFECTS IN CHEMICAL REACTORS .I. REACTANT MIXING IN BATCH AND FLOW SYSTEMS

Fractional conversion is calculated as a function of reaction time for sth-order reactions (s ≥ 0) with space-dependent specific rate constants. The mass and energy balance equations are taken to be decoupled, and mixing in the direction of any local reaction rate nonuniformity is assumed to be either absent or infinitely rapid. For continuous tubular and batch reactors, necessary and sufficient conditions are derived for the existence of a difference between the conversion histories for the two mixing extremes. It is found that when radial mixing in a tubular reactor has an effect, it is to enhance the fractional conversion, regardless of the nature of the residence time and local reaction rate distributions. Similarly, it is found that mixing in a batch reactor either increases or does not affect the overall conversion at a given time. The relationship of this work to existing studies of mixing effects in continuous-stirred-tank reactors is discussed. © 1969.