الفهرس 
CHAPTER (1) INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
The need for high quality water significantly increases over the years due to the increasing population and fresh water shortage. Desalination is the most effective solution to this problem. The Multi-Effect Desalination (MED) is one of the successful desalination technologies as it requires lower pumping power, lower heat source temperature (lower than 70oC) and lower number of effects compared with multi stage flash desalination for the same gain ratio (GR). Adding the Thermal Vapor Compression technology (TVC) to MED dramatically increases the GR. For these reasons, mathematical modeling for parallel and forward feed configurations of both MED and MED-TVC systems is established based on the first and second laws of Thermodynamics. A computer program has been developed using MATLAB program to simulate this system. A comparison between the program results and the actual plants data proves the program validity. The main design parameters that greatly influence the performance of MED-TVC plant are number of effects (NE) , heating steam temperature (entering first effect), last effect temperature, top brine temperature (TBT) or the first effect’s temperature, salt concentration ratio between the rejected brine and feed seawater, and the pressure of motive steam entering the ejector. A parametric study has been carried out to investigate the effect of the previously mentioned parameters on the GR, specific heat transfer area (SHTA) and specific total exergy destruction (STED). Also, the effects of using different values of temperature difference between effects and different effects feed flow rates for MED-TVC system are investigated. The obtained results indicate that the GR increases with increasing each of number of effects, last effect’s temperature, salt concentration ratio up to 2, and motive steam pressure. The SHTA increases with decreasing both TBT and motive steam pressure, while the SHTA decreases with increasing each of NE, Thermodynamic Analysis of Multi-Effect Seawater Desalination last effect’s temperature, and salt concentration ratio. Moreover, the study showed that STED increases with decreasing NE, decreasing TBT and increasing motive steam pressure. The total and subsystems exergy losses of MED-TVC desalination system have been evaluated. The results show that the higher percentage of exergy destruction occurs within the ejector, which represents about 60% of the total exergy destruction. While, the exergy destruction inside effects itself represents about 33% of the total exergy destruction in MED-TVC system. The results also show that, using different values of feed water rates for effects causes to decrease GR or increasing the salt concentration over the allowable limits. While, the use of different temperature differences between effects greatly increases the SHTA. Some operating parameters for the parallel feed MED-TVC system have been optimized using Greedy Search Optimization. The optimization results indicate that the optimum value of the first effect’s temperature ranges from 55.8oC to 67.6oC, the optimum ejector’s compression ratio ranges from 1.9 to 3.9 and the last effect’s temperature ranges from 42.8oC to 46.5 oC.