Experimental and theoretical investigation of the reactive granulation of sodium carbonate with dodecyl-benzenesulfonic acid

Sodium dodecyl-benzenesulfonate is an industrially important anionic surfactant, used in detergent powders and other cleaning products. It is produced by the neutralisation of dodecyl-benzenesulfonic acid with a liquid or a solid base. In the latter case, called dry neutralisation, the acid simultaneously acts as a granulation binder and the reaction kinetics determine not only the overall conversion but also the properties of the formed granules. In this work, the measurement of the kinetics of dry neutralisation using a laboratory-scale mechanically agitated granulator is described. The volume of evolved CO2, which is a by-product of the reaction, has been recorded as a function of time for several temperatures and agitation rates. A mathematical model of the process has been formulated and used in conjunction with experimental data to calculate the reaction rate as a function of operating parameters.

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► Methodology for the measurement of reaction kinetics during reactive granulation has been developed.
► Mathematical model of dry neutralisation in an agitated powder bed was formulated and validated using experimental data.
► Dependence of reaction conversion and granule size distribution on temperature and agitation rate was measured.