Dosing-free online cleaning method and device of reverse osmosis system

Abstract

The invention discloses a dosing-free online cleaning method and device of a reverse osmosis system. According to the method and device, by means of the osmosis principle, reverse osmosis system produced water is used as a cleaning medium for conducting online cleaning on a membrane part; the method specifically comprises the steps that under the situation that a reverse osmosis system high-pressure pump does not halt, a cleaning pump re-injects the produced water into the membrane part, and by controlling the cleaning pump flow and the differential pressure between the water producing side and the water inlet side of the membrane part, the produced water osmoses to the outer side of the membrane part from a membrane part central pipe (the water producing side) under the action of osmoticpressure and is discharged from the concentrated water side along with inlet water of the membrane system raw water side; the device specifically comprises a cleaning tank, the cleaning pump and cleaning valves installed on a water producing pipeline. The grouping cleaning method and device are provided for the large system; the method is simple to implement, the safety of membranes can be ensured, the construction cost is low, and the method and device are suitable for a new system or transformation and upgrading and can be used in the field of reverse osmosis membrane and nanofiltration membrane application of industrial wastewater, sea water desalination, brackish water desalination and the like.

Description

technical field [0001] The invention belongs to the field of membrane technology, and in particular relates to a drug-free online cleaning method and device for a reverse osmosis system. Background technique [0002] Principle of osmosis: A membrane that is selective to the permeable substance is called a semi-permeable membrane. When the same volume of dilute solution (such as fresh water) and concentrated solution (such as salt water) are placed on both sides of the semi-permeable membrane, the dilute solution The solvent in the medium will naturally flow through the semipermeable membrane to the side of the concentrated solution, a phenomenon called osmosis. When the osmosis reaches equilibrium, the liquid level on the concentrated solution side will be higher than the liquid level of the dilute solution by a certain height, which forms a pressure difference, which is the osmotic pressure. [0003] The principle of reverse osmosis: If a pressure greater than the osmotic ...

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Problems solved by technology

Therefore, the patent has no utility;

[0010] 2. High manufacturing cost

[0012] 1) Flushing with concentrated water produced by reverse osmosis will cause secondary pollution to the membrane elements

Concentrated water is a by-product after reverse osmosis. Compared with raw water, the content of ions, organic matter, and microorganisms is increased. Using concentrated water as a flushing medium will cause secondary pollution to the membrane surface, which will not only fail to achieve the flushing effect, but will also aggravate membrane fouling. ;

[0013] 2) The "back suction" flow rate of the produced water is small, and the cleaning effect is not obvious

According to the specification of the patent, the patent needs to rely on adding sodium chloride electrolyte to the concentrated brine tank to increase the "suction" during the implementation process, and the process of adding electrolyte requires manual operation;

[0014] 3) Control parameters are easily affected by parameters such as water temperature and recovery rate. The calculation of parameters is troublesome, which is not conducive to automation, and the cleaning effect is easily affected.

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