Ultralow-pressure membrane separation device for desalinating bitter and salty water

Abstract

The invention discloses an ultralow-pressure membrane separation device for desalinating bitter and salty water. The ultralow-pressure membrane separation device comprises a precise filter, an ultrafiltration membrane system, an ultrafiltration membrane dialysis tank, a nanofiltration (or low-removal-rate reverse osmosis) membrane system, a nanofiltration (or low-removal-rate reverse osmosis) membrane dialysis tank, a reverse osmosis membrane system, a pump and pipelines for connecting various parts; after raw water (the bitter and salty water) is filtered through the precise filter and then introduced to an ultrafiltration membrane for filtration, after the filtration of the ultrafiltration of the ultrafiltration, ultrafiltration dialyzate is introduced into a first-stage nanofiltration (or low-removal-rate reverse osmosis) membrane for treatment, a first-stage concentrated solution is discharged outwards or is used for a backwashing ultrafiltration membrane, or is processed by an energy recycling device so as to increase the pressure for the ultrafiltration dialyzate to undergo first-stage nanofiltration (or reverse osmosis), and water produced from the first-stage nanofiltration membrane is then introduced into a second-stage reverse osmosis membrane system; and second-stage dialyzate is qualified fresh water, and a second-stage concentrated solution is applied to the backwashing ultrafiltration membrane or is discharged outwards or recycled. The ultralow-pressure membrane separation device has the advantages of extremely low equipment operation pressure, good effect on desalinating the bitter and salty water, low equipment operation cost and the like.

Description

technical field [0001] The invention discloses an ultra-low pressure brackish water desalination membrane separation device, which belongs to the technical field of brackish water desalination membrane equipment manufacturing according to the International Patent Classification (IPC), and in particular relates to an ultra-low pressure membrane for brackish water desalination separate system. Background technique [0002] The acquisition of fresh water resources is a major environmental and survival issue that people face, and countries attach great importance to technology research and development and investment in this area. The desalination technology of brackish water is an important way to obtain fresh water resources, especially in my country where fresh water resources are scarce, but brackish water resources are widely distributed, so brackish water desalination technology has become a very realistic and meaningful way to obtain water resources in my country . At pre...

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Problems solved by technology

[0003] The current membrane separation equipment must operate under high pressure to overcome the high osmotic pressure of the brackish water because of the high salt content of the brackish water. At the same time, the components that contact the brackish water must have strong corrosion resistance, which means Higher requirements are put forward for the materials of the equipment, especially the pipelines and pumps in contact with brackish water need to be resistant to corrosion and high pressure, resulting in high requirements for raw materials and materials for equipment manufacturing, high equipment manufacturing requirements, and high manufacturing costs

In addition, the existing membrane separation method for desalination of brackish water is too long and complicated, and requires the consumption of various chemicals. The core process of desalination uses only one reverse osmosis or nanofiltration membrane, which cannot cope with changing water quality, and the quality of produced water fluctuates greatly. , special membrane elements with stable performance must be used

[0004] Chinese document CN 201284253 discloses a nanofiltration membrane brackish water desalination system device, the working process is as follows: brackish water→water tank→water pump→security filter→ultrafiltration component→water tank→water pump→first-stage nanofiltration membrane desalination device→water tank → water pump secondary nanofiltration membrane desalter → water tank → fresh water, however, the above device repeatedly applies nanofiltration membrane filtration, and the molecular weight cut-off of nanofiltration membrane is relatively large, so it can only partially remove inorganic ions that are toxic and harmful to human body in brackish water ( Such as fluorine, arsenic, etc.) and low molecular weight organic matter, the quality of the product water is not easy to pass, and the high recovery rate claimed in this invention is impossible to achieve

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