Distribution of heating surface areas in sugar juice evaporation process for maximum energy efficiency

Abstract

AbstractThe conversion of diluted sugar juice into raw sugar and molasses requires thermal energy for evaporating the water content in sugar juice. The supply of thermal energy is saturated steam at around 200 kPa. The efficiency of energy use by the process is determined from the amount of saturated steam to process a given amount of sugar juice. It depends on heating surfaces of the juice heater and the evaporator. This article investigates the improvement in energy efficiency of the sugar juice evaporation process that has five evaporator effects by distributing fixed heating surface areas of the evaporator and the juice heater optimally. It is shown that there exists the optimum distribution of heating surfaces that results in the maximum energy efficiency for a specified sugar juice flow rate.Practical applicationsA mathematical model of quintuple‐effect evaporator in sugar juice evaporation process is presented in this paper. The proposed model should be useful for the design and analysis of the process. The article also presents an example of the application of the proposed model in determining the optimum distribution of fixed total heating surface areas that results in the maximum energy efficiency. The method presented in this article can be used by a process designer to determine the optimum distributions of evaporator and juice heater surface areas when total heating surface areas and sugar juice flow rate are given.