Dynamic simulation of plate and frame heat exchanger undergoing food fouling: Coconut milk fouling case study

The mathematical modelling and-simulation of plate heat exchangers with rapid fouling effects are presented. Crank-Nicolson's method and the ghost-node technique were used to solve the thermal model. Effects of fouling were added to the model through the overall heat-transfer coefficient correlation. A fourth order Runge-Kutta scheme was used to obtain the integral value of the fouling model. An experimental study of coconut-milk pasteurization section developed previously was used as a case study. The flow configuration adopted was 1 pass 2 channels of hot water countercurrents with 1 pass 1 channel of coconut milk. The variation of the coconut milk outlet temperature and the overall heat-transfer coefficient with time from the simulation agreed well with those obtained from the experiments. The algorithm presented in this research work can be used to provide a result of step change of selected input variable(s), i.e. fluid-flow rate and temperature. The feature allowed the control strategy to be specified in order to bring back an outlet temperature of one process stream when the process was undergoing fouling. Ultimately, the algorithm was also used to simulate the case of 1 pass 25 channels of hot water countercurrent with 1 pass 25 channels of coconut milk. The results of this case study indicated that adjustment of inlet temperature of hot water was appropriate from the energy consumption point of view.