Thermodynamic design and parametric study of MED-TVC

The present work summarizes parametric optimization technique of multi effect desalination with thermal vapor compression (MED-TVC) process to increase gain output ratio (GOR) value. In order to increase GOR value, a simulation model of MED-TVC system is presented. This simulation can provide engineers a cost-effective tool for thermodynamic design, development and optimization of the thermal desalination plants. Also, a mathematical model has been developed which can predict the effect of all parameters on total capacity, performance ratio of the system, temperature difference between effects and pressure on each effect under design and operating conditions. The transient nature of temperature during the seasons is modeled by ordinary differential equations based on mass and energy balance. An actual system is used to compare GOR values of theoretical and experimental results. In this paper, it is shown that by means of parametric study, the computer simulation tool developed will help designers to achieve the best setting for desalination process to increase GOR value and minimize the energy consumption. The comparison between the simulation results, with experimental data well proves the validity of parametric study.

• Simulation model is an effective tool to design MED-TVC process with any desire capacity. • The method of parametric study is an appropriate tool to estimate the optimum effective values in order to increase GOR value. • Attention to process optimization, at the beginning of process design, would highly affected on decreasing required heat transfer areas in the system or increasing total capacity and GOR value. • It is necessary to keep process data on design condition. Acknowledgments Authors would like to express their appreciation to the Fan-Niroo Company (Tehran, Iran), for their valuable cooperation and also thanks to Bonian-Daneshpajouhan Institute (Tehran, Iran) and our co-workers particularly Mrs. Mohebbinia, Mrs. Saadatmand and Mrs Alishiri. Nomenclature B CP D0 D Dr R F L Mc GOR Brine blow down mass flow rate, ton/h Capacity coefficient, kJ/kg°C Steam entering first effect mass flow rate, ton/h Distillate product mass flow rate, ton/h Entrained steam mass flow rate, ton/h Rejected water mass flow rate, ton/h Seawater feed to effects mass flow rate, ton/h Latent heat, kJ/kg Seawater mass flow rate, ton/h Gain output ratio T S X m P Temperature of effect, °C Motive steam mass flow rate, ton/h Salt concentration, ppm Mass flow rate Steam pressure Subscripts i B F f n p s sw T Index Brine Feed Condenser product Number of effects Primary steam Motive steam Seawater Total