| Seawater desalination technology with wind energy as power source has attracted an increasing interest and found a rapid development all over the world in the last years.However,the power supply of non-grid-connected wind power is not stable,how to make it match with the performance of energy use processes is a key technology in engineering.Dafeng Port Seawater Desalination Engineering is a demonstration project located in Dafeng City,Jiangsu Province.The first-stage of the project has been granted to be energy-suppled by non-grid-connected wind power.With seawater as the source,the first-stage project should meet the demand of 6000 t/d industrial water,5000 t/d domestic drinking water and 720 t/d pure water at the same time.Based on the quality of the required fresh water and the power supply characteristics of the local wind energy,a non-grid-connected wind power seawater desalination process was developed in the present research work.The technological design,equipment selection and setting up,and regulation and operation of the engineering were further conducted step by step.The results showed that the seawater desalination engineering was low in construction investment and could be performed steadily.In the present research work,a technical route for the seawater desalination and advanced treatment was put forward firstly,based on the quality of the seawater source and the required quality of the fresh water after desalination,as well as the power supply characteristics of the local wind energy.The technical route was “pretreatment ? seawater desalination ? advanced treatment of desalinated water”.Then,comparing with the processes of multieffect distillation and multi-stage flash distillation,reverse osmosis membrane method was identified as the feasible process for the seawater desalination project,which should adapt to the performance of the local wind energy production.The developed process was “coagulation sedimentation tank ? V-type filter ? self-cleaning filter ? ultrafiltration ? seawater desalination system ? first advanced treatment ? second advanced treatment”.Finally,the Dafeng Port Seawater Desalination Engineering was constructed after engineering design of the process,and selection and setting up of the equipment.Regulation and operation of the demonstration project was conducted for more than 2 months in the present research work.The results showed that the subsystems such as seawater pretreatment,desalination and advanced treatment of the desalinated water were all in working order.In order to adapt to the supply fluctuation of the local non-grid-connected wind power,a strategy was developed to ensure the normal operation of the seawater desalination and advanced treatment processes.As a result,self-correction of water processing load was realized by the introduced automatic control system.The practical operation of the demonstration project showed that the an effluent turbidity less than 900,10,1 and 0.15 NTU was obtained in the pretreatment unit,coagulation sedimentation tank,V-type filter and ultrafiltration unit,respectively.The ratio of desalinization averaged 99.5% with a conductivity of 31000~34000 and 140~250 ?S/cm in the influent seawater and the final effluent,respectively.The water quality after the first and the second advanced treatment met well the requirement of Sanitary Standard for Drinking Water(GB5749-2006)and Bottled Drinking Pure Water(GB71323-1998),respectively.So far,the first-stage of Dafeng Port Seawater Desalination Engineering is still in performence safely and steadily,with a daily output quantity of 5000 t drinking water and 100,000 bottles of fresh water,producing a good economic benefit.Construction and successful operation of the demonstration project has presented a good example for the application of non-grid-connected wind power seawater desalination process. |
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