Reverse osmosis system operation failure, so analyze and solve away!

Reverse osmosis system operation failure, so analyze and solve away!

Reverse osmosis, also known as reverse osmosis, is a membrane separation operation that uses a pressure difference as the driving force to separate a solvent from a solution. It is called reverse osmosis because it goes in the opposite direction from natural osmosis. Reverse osmosis is a membrane separation technology that mainly utilizes the osmotic principle of a semi-permeable membrane by applying a pressure to it in a certain way to overcome the natural osmotic pressure so that water in a concentrated solution permeates into a dilute solution, called reverse osmosis. The device composed of reverse osmosis elements is a reverse osmosis device.

Widely used in water desalination desalination, purified water, high-purity water preparation, can be used as a separation of bacteria, heat, colloids, and organic matter for the purpose of an advanced process equipment.

Failure caused by the deterioration of feed water quality
In the initial design due to the feed water quality is better, the system operation is more stable, but with the subsequent deterioration of the feed water quality, in the system can not be optimized to improve the pretreatment, reverse osmosis device produces a more serious operational failures.
Specifically manifested in the faster decline in water production, operating pressure and differential pressure rise faster.

Pre-treatment performance degradation caused by the failure
The water production decreases faster, and the operating pressure and differential pressure increase faster.
Specifically manifested in: CMF or UF membrane filament fracture; buffer tank bacteria, microbial reproduction is serious; multi-media filter media or bias flow; activated carbon filter filter media pulverization or microbial reproduction is serious.

Failure caused by the use of poor quality filter element in security filter
When the output of the security filter increases, the filter element is easy to be deformed or the filtration precision fails to meet the requirements, so that the pollutants directly enter the reverse osmosis device.
Specifically manifested in: security filter cartridge diameter is small; cartridge quality is poor, filtration precision can not meet the requirements; cartridge pressure is not tight, and easily deformed.

Failure caused by improper selection and dosing of scale inhibitor
Scale inhibitor as the reverse osmosis safe and stable operation of the “God of protection”, because of its excellent effect, low operating costs and become the mainstream of the current form of scale inhibition, but in the scale inhibitor selection, dosing and mixing has produced many problems.
Specifically manifested in: scale inhibitor performance and water quality mismatch; scale inhibitor metering pump performance is not reliable; scale inhibitor over-dilution; scale inhibitor metering box serious pollution.

​​​​​​​Failure caused by improper dosage of other chemicals
For different water quality need to add a certain number and type of chemicals to increase the treatment effect on the raw water, but due to the existence of a variety of reasons, the non-correct use of these chemicals and adding, some will produce serious consequences.
Specifically manifested in: unsuitable flocculants bring serious membrane contamination; oxidant overdose caused by membrane oxidation; reducing agent overdose caused by serious membrane fouling.

​​​​​​​Failure caused by instrumentation failure
At present, the general reverse osmosis device are used on the imported digital display instrumentation, some instruments in the correct installation of the premise, the flow rate display is very accurate as well as stable readings; but other types of digital display instrumentation in the operation of the numerical fluctuations in the amplitude of the relatively large, especially some of the instrumentation has the function of parameter setting, the display of the amount of water produced by the human factor control, so that act as the eyes of the reverse osmosis instrument will affect the technicians on the Reverse osmosis judgment.
Specifically manifested in:
Concentrated water flow rate display bias (actually smaller) caused by reverse osmosis recovery rate is too high to produce scaling; concentrated water flow rate display bias (actually larger) caused by reverse osmosis recovery rate is too low to produce differential pressure; flowmeter readings fluctuations, can not be correctly in accordance with the ratio of 10 to 15% judgment.

Failure due to defective design and improper operation and maintenance of the device
Reverse osmosis devices appear a variety of problems are more, some systems in the design of the defects, but also in the daily operation and maintenance of the process of some of the deviations, causing more serious operational hazards.
Specifically manifested in:
In the initial design of high-pressure pump head selection is low, in the temperature or water quality changes caused by the water production can not meet the design requirements;
Membrane element oxidation caused by the increase in water flux and water quality decline;
Inverted or broken brine seals cause the actual recovery rate is too high, resulting in scaling and water quality decline;
O-ring damage caused by the decline in water quality;
The mixed use of new and old membrane elements and different types of membrane elements causes system performance degradation;
Pressure vessel thick water thrust ring and thick water outlet overlap or partially overlap caused by high recovery rate and scaling phenomenon;
Pressure vessel length is too large to cause concentrated water leakage to the produced water side so that the quality of produced water is degraded;
No inter-segment pressure gauge can not reliably analyze and judge the reverse osmosis operation;
Large pressure difference causes damage to the membrane element due to telescope effect;
The increase of back pressure of produced water causes the decrease of water production;
Reverse osmosis arrangement unreasonable cause local membrane element water flux increase, pollution speed up;
Reverse osmosis recovery rate design is unreasonable, the number of membrane elements is small;
Particulate contamination of the membrane element to produce more serious mechanical fouling, a section of the differential pressure is large, water production and water quality deterioration;
Pollutant deposition and bacterial and microbial contamination caused by system shutdown.
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