Dynamic Simulation of Plate and Frame Heat Exchanger Undergoing Rapid Fouling

Mathematical model and dynamic simulation technique of plate heat exchangers (PHEs) with rapid fouling effects were presented. Crank Nicolson’s method and the ghost node technique were used to solve the thermal model. Effects of fouling were added to model through the overall heat transfer coefficient correlation. Rung Kutta 4 was used to receive the integral value of the fouling model. An experimental study of coconut milk pasteurization section by Pichitvitayakarn (2006) was used as a case study. The flow configuration was 1 pass 2 channels of hot water countercurrent with 1 pass 1 channel of coconut milk. Evolution 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 allows control strategy to be specified in order to bring back an outlet temperature of one process stream when the process is undergoing fouling. 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 in term of energy consumption.