HEAT SAVING IN EVAPORATIVE CRYSTALLIZATION BY INTRODUCING A HEAT PUMP

Abstract

In this work theoretical calculations had been made for suggested methods of heating mother liquor in a crystallizer for both kinds of evaporative crystallization process. These suggested designs aim to reduce and save the consumption of heat which leads to reducing operational costs for the two kinds of crystallization. It was found that in direct evaporative crystallization: when a heat pump was added to heat the medium (hot air), it had saved energy consumption range between 81 % to 93 % at different values of coefficient of performance (COP). In the second type - indirect evaporation, when a heat pump was added on line containing the mixture of vapor from crystallizer and steam from jacket outlet, this mixture becomes a heat source to the heat pump in order to preheat the inlet steam to the jacket. Calculations of this suggested design showed that the saved energy consumption was 8 % to 26 % at different COP.