High-yield and one-time desalted water preparing process device and method

Abstract

The invention provides a high-yield and one-time desalted water preparing process device and method. The process device comprises a front ultrafiltration water tank, a pretreatment system, a middle water tank, a reverse osmosis system, an electrically driven ionic membrane device and an online SDI value control system. The process method includes the steps that 1, the reverse osmosis treatment scale of the device and the treatment scale of the electrically driven ionic membrane device are set; 2, raw water is fed into the pretreatment system; 3, reverse osmosis is conducted on the pretreated water; 4, reverse-osmosis concentrated water enters the electrically driven ionic membrane device for desalting treatment; 5, the produced water of an electrically driven ionic membrane is detected by the online SDI value control system, when SDI is smaller than or equal to 3, the produced water of the electrically driven ionic membrane returns to the middle water tank at the front end of the reverse osmosis system, and when the SDI is greater than 3, the produced water of the electrically driven ionic membrane returns to the front ultrafiltration water tank at the front end of the pretreatment system. The process can improve the one-time desalted water reverse-osmosis yield and has the advantages of being high in system yield, capable of saving energy, low in operation cost and making the system safely and stably operating for a long period of time.

Description

technical field [0001] The invention relates to the field of water treatment, more specifically to a process device and method for one-time desalinated water with high yield. Background technique [0002] The reverse osmosis process has the advantages of simple operation and stable water quality, and has currently occupied a dominant position in the primary desalinated water preparation market. However, due to the phenomenon of concentration polarization, the risk of membrane fouling is high, resulting in a low water production rate, which generally can only reach 50% to 70%, resulting in a lot of waste of water resources. Today, when water resources are scarce and the pressure of water-saving and emission-reduction policies is increasing, increasing the yield of the primary desalinated water reverse osmosis system is of great significance for saving water resources and improving economic benefits. [0003] At present, the method of increasing the reverse osmosis yield of t...

AI Technical Summary

Problems solved by technology

[0004] First, as the number of stages increases, the concentration of reverse osmosis feed water continues to increase, and the risk of membrane fouling due to the phenomenon of concentration polarization increases rapidly. The higher the number of stages, the greater the risk of membrane fouling;

[0005] Second, due to the limitation of the risk of membrane fouling, the space for increasing the yield by increasing the number of stages is extremely limited, and the limit value of the total yield of the system can only be about 75%.

[0006] Third, in order to avoid membrane fouling, it is necessary to greatly increase the use of reverse osmosis scale inhibitors, fungicides and other agents, which not only increases the cost of water production, but also causes secondary pollution of concentrated water to intensify

[0007] In order to improve the membrane fouling and increase the water yield, there is also a high-pressure disc tube reverse osmosis (DTRO) process, which can increase the water yield to 80%-90%, but the operating pressure of this process is extremely high, and the investment in equipment is too large , high cost of water production, no promotion value

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