Definition of desalination
Desalination is the use of seawater to produce fresh water. It is an open source incremental technology to realize the utilization of water resources, which can increase the total amount of fresh water, reverse osmosis method and is not affected by time, space and climate, with good water quality and reasonable price, which can guarantee the stable water supply of coastal residents’ drinking water and industrial boilers. Currently, the seawater desalination methods used include seawater freezing method, electrodialysis method and distillation method. Currently, reverse osmosis, which USES reverse osmosis membrane, quickly occupies the market due to its advantages of simple equipment, easy maintenance and modular equipment, and gradually replaces distillation method to become a widely used method.
Marine desalination equipment
Fully consider the requirements of customers for design and production, according to the particularity of the application of ships and carried out a special design, its small size, light weight, land saving, easy installation, strong adaptability, can be installed in the narrow crowded cabin, deck, crew cabin, aisle and other space. The equipment is easy to operate and maintain, as long as there is seawater and electricity, fresh water can be provided immediately after starting. High desalination rate, stable performance, safe and reliable, innovative and ingenious design, avoid frequent cleaning, no environmental pollution. Its frame is made of stainless steel, rust and corrosion resistant. Wide range of power supply (220-380415v /50HZ/60HZ/ three-phase), can adapt to most of the domestic production of ships. Desalination water quality meets the national standards for drinking water quality.
In reverse osmosis desalination, only water molecules and a small number of ions can pass through the reverse osmosis membrane, and other ions and impurities will be trapped and concentrated as the water decreases. This method is very energy efficient because there is no phase transition. The pore diameter of reverse osmosis membrane is < 10×10-10 m, which can filter various bacteria, viruses, heat sources and other pollutants to obtain high-quality pure water. Low production cost with low salt and other impurities.
Seawater desalination pump of analysis of the characteristics
Currently, there are three kinds of seawater desalination high-pressure pumps used in reverse osmosis seawater desalination treatment system: reciprocating positive displacement pump, multi-stage centrifugal high-pressure pump and high-speed centrifugal pump. These products in foreign technology has been relatively mature, products have been serialized.
Reciprocating positive displacement pump is mainly used for the rated flow of lower occasions, usually flow <80mh, it is characterized by: high efficiency, generally more than 85%, and high efficiency range, corresponding to a certain flow, can reach different head, basically can ensure the high efficiency point. This characteristic is suitable for reverse osmosis seawater desalination. However, due to its complex structure and large volume, reciprocating positive displacement pump loses its superiority when the flow rate is over 180m3h.
There are the following types of multistage centrifugal high-pressure pumps: horizontal open multistage centrifugal high-pressure pump segmental multistage centrifugal high-pressure pump and stainless steel stamping pump. Horizontal open multi-stage centrifugal pump is suitable for occasions where the flow rate is larger than 220m3h, the larger the flow rate, the higher the efficiency of the pump, the efficiency up to 75%~85%, characterized by small axial thrust, convenient maintenance, but high manufacturing cost section multi-stage centrifugal high-pressure pump for medium flow,80~220m3h. The efficiency is 65%80%, characterized by simple structure, small size, light weight and relatively cheap price. Stainless steel stamping pump is only used for small and medium flow occasions, usually flow <95m3h, its characteristics are: low efficiency, generally less than 70%, but small size, light weight, easy to operate and maintain
High speed centrifugal pump is suitable for small flow,10~70m3h3, pump efficiency of 50%~75% is characterized by small volume, low efficiency and high noise.