Impact of the heating rate on the thermosensitive aggregation: Experimental results and mathematical model

Abstract

In this paper a comprehensive study on the influence of heating rate on thermosensitive flocculation is presented. Experimental investigation was performed using a laboratory setup consisting of thermostated mixing tank with four baffles agitated by a mechanical propeller. PSD and the resulting mean aggregate size of a model suspension system consisting of calcium carbonate and a p(NIPAM-co-DADMAC) copolymer in RO water was measured with a modified laser particle sizer. It is found that in the studied range of heating rate (from 0.29K/min–3.73K/min) the final state of the system is almost identical regardless the heating rate. A semiempirical floc growth kinetics model was proposed and verified. In order to respect the effect of heating regime a parameter named the heating regime efficiency KHR was introduced. The dependence of the model parameters on dimensionless flocculant dosage DF*, heating rate HR and heating regime efficiency KHR was described by a power-law dependence. The experimental data and model predictions were found to be in a very good agreement.