| The problem of lack of freshwater is already becoming an indisputable fact and it is also one of the facts which restrict the development of social economy. Seawater desalination technology is an effective means of solving the lack of fresh water and is given more attention by people. At present, seawater desalination technologies which have been industrialized mainly include MSF ((Multi-stage Flash) , MEE(much effect evaporation) and RO (reverse osmosis), etc . With the development of society and the technological progress, seawater desalination technology has been matured and widely used. But the high cost of the desalination is becoming the bottleneck of further being promoted. Therefore, the the research and development of new technology is a great meaning of contribution to improve the efficiency of energy utilization and seek the method of cut the energy consumption.The steady-state mathematical model of MSF with rejection is given, firstly basing of simulation and analysis of MSF seawater desalination system, and the objective is to minimize the water cost, which is presented as a non-linear programming (NLP) and solved by GAMS program. The result shows that the value calculated with the design method in the test is superior to that of the literature. The values of water coast and PR respectively reduce 18% and 17.2% than those in the literature, which proves the model and the optimization method are more feasible and effective. On this base, the sensitivity of parameters is analyzed, and the influence rules of the stage number and TBT in the MSF is discussed. PR increase with the TBT increasing, and the brine recycle flow, steam flow and total heat exchange area are all decreasing with the TBT increasing; PR and total heat exchange area both increasing ,while steam flow and total heat exchange area decreasing with the stage number increasing.The Seawater desalination technology is presented based on the three different strctures MMSF,OTMSF and CMSF combined with the power generation systems, and the mathematical and economic model are introduced , whose objective is to maximize total economic benefits. The results show that: (1) the economic benefits of the three strctures all appear first increases, then decreases in the same production of the fresh water; (2)when the production of fresh water increase, the benefits of OTMSF and CMSF both increase and higher than that of MMSF; but the economic benefits of MMSF rises and falls with the production of fresh water increasing, its economic benefits achieve to maximum at Md=60kg/s .Compared the optimal result, find that OTMSF is the best of the three, CMSF is superior to MMSF; (3) the total ecnomic benefits of the three appear to decline with the TBT increasing, and the total economic benefits of OTMSF and CMSF are significantly greater than that of MMSF. So the advantage of the CMSF and OTMSF is obviously better for the integration with water and power, while the OTMSF which is simple has more advantage than CMSF in the future.Thermal membrane coupling seawater desalination technology is studied in this paper, the mathematical and economic model are presented based on the system combined with MSF and RO, which are coupled with power plant, and the model is presented as a non-linear programming (NLP). One parameter rr is introduced which is the ratio of production of fresh water between RO and MSF, and the objective is to maximize total economic benefits, it is solved by GAMS program.The result shows that for a given condition, production of fresh water, the stage number of MSF, when the total production of fresh water is 76.52(kg/s), PR reaches to 10.6, the value of rr is 0.77, the total economic benefits reaches to highest. The influence factor of rr is studied , the total economic benefits is diminishing in drab and the water cost goes up with the rr increasing. So for the integration system it is good for increasing the total benefits as increasing the production of freshwater of MSF to some degree. |
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