Research On Seawater Desalination New Process Taking Blast Furnace Slag Water Waste Heat As Heat Source

With the fast development of economy, the increase in population, and the overexploitation of underground water resources, fresh water shortage has become a critical constraint for sustainable development in china. Desalination is one effective option to solve problems of water shortage. On the one hand, desalination consumes large energy, resulting in high cost, which restricted promotion, another hand, large amounts of waste heat can not be used in coastal enterprises, especially iron and steel enterprises. If combing the two, we can not only effectively reduce desalination cost, but also use the waste heat, to ease the access of water and improve the efficiency overall.In this thesis, three major desalinations and energy consumption are compaed, and obtained that LT-MED has the minimum energy, and the requirements about temperature and pressure of heat source is lowest. Currently, high temperature and medium temperature waste heat is utilizated batter in iron and steel enterprises, but low temperature water is not good. Proposing a new technology using slag water as heat source, with two set of12500t/d desalination devices in Shougang Jingtang.The main content of new process is how to use low temperature waste heat of slag water, Introducted the design process of the entire system, including two heat eschangers and power for operation, draw the main parameters of the system. In addition using the exergy method analysis the individual equipments, identified the key of improving system heat transfer efficiency is optimizing and designing heat exchangers and selecting energy dfficient pump.Finally, calculated the cost of low-temperature and low-pressure steam from heat exchanger system with cost analysis and the final cost of fresh water from desalination system in Shougang Jingtang with the new heat exchanger system. Obtained the new technology is feasible.