A new parallel competing reaction system for assessing micromixing efficiency—Experimental approach

Abstract Several kinds of methods can be used in order to study the state of mixing at molecular scale in stirred reactors. Conductometric and optical methods have not enough resolution. The aim of this work is therefore to propose a chemical reaction which acts as a molecular probe for assessing micromixing efficiency. A literature review shows that the number of available test reactions is limited. We propose a new system of parallel competing reactions A + B → R and C + νB → S whereby the state of micromixing in industrial reactors can be studied. The first reaction is a neutralization, the second one is the Dushman reaction between the iodide and iodate. We show that the formation of iodine (S) under the influence of an acid (B) in an alkaline medium (A) is a measure of segregation. This system makes it possible to study the influence of feed time, feed location and reactant concentrations on segregation. The method is validated by a study of mixing in standard stirred tanks of one and twenty litres. Scale-up rules are proposed.