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ISSN Online: 2379-1748

ISBN Flash Drive: 978-1-56700-472-4

ISBN Online: 978-1-56700-471-7

3rd Thermal and Fluids Engineering Conference (TFEC)
March, 4–7, 2018, Fort Lauderdale, FL, USA

EFFECT OF CHANGES IN INPUT PARAMETERS ON THE OPERATION OF A MED-TVC PLANT

Get access (open in a dialog) pages 709-723
DOI: 10.1615/TFEC2018.ewf.021614

Abstract

Multi-Effect-Desalination (MED) process is an attractive approach for desalination because of the combination of low economic costs and low energy consumption, especially when it is combined with electricity cogeneration using solar or waste heat. However MED may be exposed to fluctuations in input parameters during operation. Therefore, there is a requirement to analyze the transient behavior of such MED systems. In this work, a dynamic model is developed by solving the time-dependent conservation equations of mass, energy and salt using available data from a MED with thermal vapor compression unit (MED-TVC) plant installed in western UAE. The model is validated with experimental data available in the literature. The model is then used to examine the effect of the fluctuations of the main operational parameters on the plant behavior and performance. The results show an increase in the total production of fresh water when the cooling seawater flow rate decreases which leads to a higher Gained Output Ratio (GOR). On the contrary, a reduction in cooling sea water temperature leads to a lower fresh water production and GOR. It is also noted that a change in motive steam flow rate has only a slight effect on the GOR. For the current MED-TVC configuration and dimensions, it is recommended to limit the reduction in the seawater cooling flow rate to under 12% of the steady state value to avoid evaporators dry out. Also, a reduction in the motive steam flow rate and cooling seawater temperature of more than 20% and 35% of the steady state values may lead to evaporators flooding.