A model of laminar micromixing with application to parallel chemical reactions

The effect of laminar micromixing on parallel reactions was studied experimentally and interpreted theoretically using a new model of laminar micromixing, developed by applying an integral transformation to material balance equations in the Lagrangian frame of reference. A solution of sodium hydroxide was contacted with a premixture of hydrochloric acid and ethyl chloroacetate solutions in two reactors: a semibatch tank reactor and a twin-screw extruder. The viscosities of the mixed solutions were increased to 0.3 Pa s with polyethylenepolypropylene glycol to obtain a laminar flow regime in both reactors. The selectivity of the parallel reactions was then dependent on the mode of operation, intensity of mixing, initial stoichiometric ratio and volume ratio of the mixed solutions. The model was used to determine an energetic efficiency of mixing based on the results of the parallel reaction experiments; the procedure proposed enables a direct and strict comparison to be made of systems with different geometries and/or mode of operation. (C) 1998 Elsevier Science S.A.