Reverse osmosis equipment how to extend the service life of the equipment?

The quality of pretreatment is the key to the stable operation of reverse osmosis equipment. When the reverse osmosis equipment feed water using groundwater, the use of quartz sand and activated carbon pretreatment is no problem, when using surface water is different.

    1, reverse osmosis equipment pretreatment chemicals
    With the agents used in the treatment, including coagulants, flocculants, oxidizing agents, reducing agents, scale inhibitors, etc., especially coagulants and scale inhibitors, the selection of these agents, the dosage and even the method of pharmaceutical dispensing will have a great impact on the operation of reverse osmosis.

    Usually, we will pay attention to detect the iron content of feed water, in fact, high aluminum content in feed water will also cause reverse osmosis membrane pollution. Aluminum contamination of the membrane is caused by aluminum hydroxide precipitation, aluminum hydroxide precipitate usually exists in the form of colloid, is a kind of amphoteric hydroxide, in the pH range of 6.5-6.7 has a very small solubility, if the aluminum coagulation process is carried out in too high or too low pH, aluminum ions will be into the reverse osmosis device to cause pollution of reverse osmosis membranes, therefore, for the use of aluminum salts as a coagulant of pre-treatment Therefore, for the pretreatment system using aluminum salt as coagulant, the pH value should be controlled at 6.5-6.7, so that the solubility of aluminum can reach the minimum, pay attention to adjust the dosage according to the water quality in time, and test the aluminum content of the pretreated water regularly if possible and control it at 0.05mg/L or less.

    In order to prevent scaling on the thick water side, we usually add scale inhibitor, the current scale inhibitor to some organic acids, organic phosphates compounded to achieve the purpose of scale inhibition, dispersion. If the choice or control is not appropriate, these organic substances will be contaminated with reverse osmosis membrane elements, but also it will become a breeding ground for bacterial microorganisms, and the operation of reverse osmosis to bring more harm.

    2、Temperature
    Maybe we all know that the temperature of the reverse osmosis membrane element has a great influence on the flux, so in the calculation of water production when the temperature is calibrated in order to compare with each other. So in the winter water temperature is low in the place of reverse osmosis pretreatment system will be designed heating equipment, which can effectively ensure that the winter reverse osmosis equipment can also reach the design output.

    In fact, SiO₂ precipitation in the membrane element, also with the reverse osmosis device of the water temperature has a close relationship, the concentration of silica in the concentrated water, 25 ℃ can not exceed 100mg / l, 5 ℃ can not exceed 25mg / l. Therefore, when there is no heating equipment in the pretreatment system in the winter to pay close attention to silica precipitation on the membrane element of the contamination of the issue of strict control of the concentration of silica in the water, its value can not exceed in the temperature of the silicon dioxide content, and its value can not exceed the concentration of silica in the concentrated water. Its value can not exceed the solubility at that temperature.

Reverse osmosis equipment operator training

 

The level of competence of the operating personnel, depending on the ability of the operating personnel to detect and correctly deal with the defects and hidden dangers of the system in a timely manner is an important factor affecting the operation of the reverse osmosis equipment. Misoperation of the operator is more harmful to the system, and the damage to the membrane element is often unrecoverable. Reverse osmosis equipment restart before and after the operation of the flushing work must be done to prevent the equipment has residual gas in the high-pressure operation, the formation of gas hammer will damage the membrane, as well as the concentration of inorganic salts on the concentrated side of the membrane is higher than the original water, easy to scale and contaminate the membrane.

 

Reverse osmosis equipment operation management

1、Regular inspection of reverse osmosis equipment

Regular inspection and timely replacement of the security filter cartridge to prevent leakage of the cartridge due to installation or quality problems caused by the reverse osmosis membrane particle contamination. When the security filter inlet differential pressure is greater than 0.15MPa, the filter element should be replaced. Generally should be checked once a month, the filter element should not be used for more than 6 months, the operation of the security filter should also be checked often enough to have gas, can not let the air brought in.

2, reverse osmosis membrane element inspection

(1) General every six months (if necessary, can be shortened), to each set of reverse osmosis of a section, two sections of the membrane element to check.

(2) Open the end cover of the pressure vessel (using special tools and operated by skilled technicians).

(3) Check the water inlet section for mechanical impurities, metal oxide deposits, bacterial microbial growth, membrane element color changes, check the membrane for scaling.

(4) If necessary, you can also draw out the reverse osmosis membrane elements for detailed inspection, and then pump the water end of the membrane element, must not be directly pumped, to put the direction of the water flow it from the pressure vessel, the same installation.

(5) Each time after the inspection to make a detailed record, in order to compare.

(3) Each meter is regularly calibrated to ensure that the meter is accurate and reliable.

4、Regularly analyze the operating data of reverse osmosis equipment and statistics.

 

Operating pressure, recovery rate (or concentrated water discharge), feed water SDI (pollution index), pH, residual chlorine and temperature are the main operating control parameters of reverse osmosis device; desalination rate, water production and differential pressure are three main monitoring performance parameters. In the operation and management must be strictly observed, never change the operating conditions at will. In particular, it is necessary to prevent the increase of recovery rate to increase the amount of water production, resulting in reverse osmosis membrane surface fouling; to prevent the SDI value exceeds the standard to continue to run, resulting in reverse osmosis membrane clogging; to prevent the maximum permissible differential pressure to continue to work above the destructive damage caused by the membrane element.