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Washing method for preventing reverse osmosis membrane or nano-filtration membrane from being polluted

A reverse osmosis membrane, reverse osmosis technology, applied in osmosis/dialysis water/sewage treatment, semi-permeable membrane separation, chemical instruments and methods, etc., can solve the problem that microbubbles cannot achieve sufficient turbulence of gas-liquid two-phase flow and scrub membranes face, inability to provide sufficient shear force, and difficulty in restoring flux, etc., to avoid environmental pollution of concentrated water, reduce scale, and avoid mass use.

Active Publication Date: 2013-09-18
OCEAN UNIV OF CHINA
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Problems solved by technology

Next, the generated gas-liquid mixed cleaning liquid is input into the reverse osmosis membrane device by another high-pressure pump to clean the organic pollutants on the membrane, and then the cleaning liquid is circulated back to the original water tank, but the microbubbles cannot reach the sufficient turbulence of the gas-liquid two-phase flow. The effect of moving and scrubbing the membrane surface; Japanese patent JP2009202063 (A) discloses a method for cleaning the reverse osmosis membrane module, the cleaning pipeline is connected with the reverse osmosis water inlet pipe, and the cleaning water pump delivers the liquid or gas-liquid mixture to the membrane surface of the element , so that the cleaning solution flows through the membrane surface at low pressure, effectively removing the pollutants stuck on the surface of the reverse osmosis membrane
The technical solutions disclosed in these patents all use air washing or a combination of air washing, water washing, and drug washing to remove the pollutants on the membrane surface when the surface of the reverse osmosis or nanofiltration membrane has been seriously polluted. It is a passive cleaning process. When the membrane fouling is quite serious, it is difficult to restore the flux by air washing and water washing, which cannot prevent it. Moreover, air washing alone cannot provide sufficient shearing force and takes a long time.

Method used

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  • Washing method for preventing reverse osmosis membrane or nano-filtration membrane from being polluted

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Embodiment 1

[0016] The reverse osmosis device involved in this embodiment adopts a one-stage reverse osmosis process and uses an energy recovery device. The reverse osmosis device is composed of a set of reverse osmosis modules. The set of modules has two reverse osmosis pressure vessels. The main structure of the reverse osmosis device includes Low pressure pump 1, security filter 2, high pressure pump 3, reverse osmosis module 4, booster pump 5, energy recovery device 6, reverse osmosis flushing water tank 7, flushing water pump 8, security filter 9, static mixer 10, inlet water Valves A1, A2, flushing water inlet valves B1, B2, concentrated water discharge valves C1, C2, flushing water discharge valves D1, D2, compressed air intake valve E, flushing water valve F, concentrated water flow regulating valve G, concentrated water Water flow regulating valve H, replacement valve J and dosing valve K; when the reverse osmosis module is working, it is divided into operating state and cleaning s...

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Abstract

The invention belongs to the technical field of seawater desalting and water treatment and relates to a washing method for preventing a reverse osmosis membrane or a nano-filtration membrane from being polluted. The washing method comprises the following steps of: firstly carrying out gas-water two-phase flow washing or simultaneous chemical washing; then extracting reverse osmosis concentrated water to wash the surface of the reverse osmosis membrane; discharging the reverse osmosis concentrated water through a concentrated water discharging valve; then, conveying pretreated water to a reverse osmosis module and displacing and discharging washing concentrated water on a reverse osmosis concentrated water side until the conductivity is recovered to 98% of the conductivity of the pretreated water; finally, closing a washing water discharging valve and opening the concentrated water discharging valve to recover normal operation of the reverse osmosis module; and sequentially washing other sets of reverse osmosis modules. The washing method disclosed by the invention is reliable in process, simple and convenient to operate, lower in energy consumption, good in economic benefits and social benefits, and environment-friendly.

Description

Technical field: [0001] The present invention belongs to the technical field of seawater desalination and water treatment, and relates to a reverse osmosis membrane or nanofiltration membrane for seawater, brackish water desalination / softening, surface water treatment and industrial wastewater and urban sewage treatment processes to prevent reverse osmosis membranes or nanofiltration membranes. The process of membrane pollution, especially a cleaning method to prevent and control reverse osmosis membrane or nanofiltration membrane pollution in seawater desalination or water treatment technology. Background technique: [0002] Reverse osmosis membranes or nanofiltration membrane systems are widely used in seawater desalination / softening or surface water treatment or industrial wastewater and urban sewage treatment and reuse. Generally, traditional pretreatment methods such as sand filtration or ultrafiltration membranes are used as pretreatment , The water after these pretreatment...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D65/06C02F1/44
CPCY02A20/131
Inventor 苏保卫吴桐高学理丛鑫
Owner OCEAN UNIV OF CHINA
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