Seawater electric desalting apparatus and method

Abstract

The invention provides a low-energy consumption seawater electric desalter and a method capable of realizing energy recovery. The electric desalter comprises an electric collection cathode, an active carbon cathode, a permeable separation medium, an active carbon anode and an electric collection anode. The invention is characterized in that the absorption of double electric layers of active carbon electrodes is used to form the structural property of super capacitance. In charging and desalting processes, ions or granules with charges can be absorbed and concentrated on the active carbon electrodes in the electric desalter, and the inner chamber of the device can recover purified water or fresh water; in discharging and electrode regenerating processes, the ions or the granules with charges absorbed on the active carbon electrodes are desorbed and return to a solution system, and the achieved thick saltwater can be used for recovering the salt in brackish water or seawater. The electric desalter can be used for desalting seawater or brackish water or the purification and the metal recovery of the waste water containing ions. The invention can desalt the seawater or the brackish water to the fresh water with the Cl concentration being less than or equal to 30 ppm, and the running cost for processing the water is less than or equal to 1 yuan per ton.

Description

technical field [0001] The invention provides a new type of low-energy seawater electric desalination device capable of realizing energy recovery and a seawater desalination method using the device. The electric desalination device can be used for desalination of seawater or brackish water, or purification of ion-containing wastewater and metal recovery . technical background [0002] At present, the commonly used desalination methods at home and abroad mainly use distillation, electrodialysis, ion exchange, multi-layer flash evaporation, reverse osmosis and so on. The latter two methods are mostly used for seawater or brackish water desalination. Among the above methods, the advantage of electrodialysis is that it is easy to operate and is suitable for treating water with high salt content. It is a coarse desalination equipment. Mixed bed is a traditional process. The advantage is that the equipment investment is low, and the disadvantage is that the operation cost is hig...

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Problems solved by technology

Among the above methods, the advantage of electrodialysis is that it is easy to operate and is suitable for treating water with high salt content. It is a coarse desalination equipment. Mixed bed is a traditional process. The advantage is that the equipment investment is low, and the disadvantage is that the operation cost is high. It needs chemical regeneration to cause secondary pollution or secondary purification. It requires slightly higher requirements for operators. It generally treats wastewater with low salt concentration; Reverse osmosis (RO??? membrane method) has only been in the Chinese market for about ten years. For example, the newly published patent application No. 200710017966.6 uses reverse osmosis membranes and devices for desalination treatment process, passing seawater through self-cleaning filters, Pretreatment in the ultrafiltration device, pressurized filtration to remove tiny particles that may exist in the feed water of the reverse osmosis system, and then increase the feed water pressure of the reverse osmosis device to perform desalination treatment; 4.02 yuan / ton, the removal rate is higher than that of electrodialysis, and the operation is convenient; the disadvantage is that the investment is relatively large. Although the operating cost is lower than that of electrodialysis, it is still as high as 4-5 degrees of electricity / ton of water, and the requirements for influent water are higher. Remove all particles larger than 1 micron; at the same time, the water yield is low, and 1 to 2 tons of fresh water can be produced for every 2 to 3 tons of raw water

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