The characteristic of reverse osmosis to obtain pure water is that the actual water production of the reverse osmosis membrane is greatly affected by the temperature. The water production of most laboratory ultrapure water machines or reverse osmosis pure water equipment is marked by the standard water production of the reverse osmosis membrane at a feed water temperature of 25 °C . As the temperature becomes lower, the viscosity of water increases, the diffusibility of water decreases, and the amount of water produced decreases as the temperature decreases. Under the same pressure, the temperature drops by one degree Celsius, and the water production can be reduced by 3~4%. The following equation is the relationship between water production flux and temperature: TCF=exp[K×(1÷(273+t)-1÷298] Where TCF is the temperature correction factor, K is the membrane material constant, and t is the influent Celsius temperature. The equation uses 25 ° C as the reference, TCF = 1 Reverse osmosis membrane temperature correction coefficient TCF Calculation method: corrected flow rate = measured flow rate × correction coefficient corresponding to feed water temperature Method for preserving reverse osmosis membrane element In order to prevent the growth of membrane surface organisms during storage and the performance degradation in subsequent operations, the membrane elements must be stored in a tailored solution. 1. New membrane element (1) The membrane element must remain wet after it has passed through the water. Even if it needs to be temporarily opened in order to confirm the quantity of the same package, it must be carried out without damaging the plastic bag. This state should be saved until use. (2) The membrane element is preferably stored at a low temperature of 5 to 10 °C. When storing in an environment where the temperature exceeds 10 °C, choose a well-ventilated place, and avoid direct sunlight, the storage temperature should not exceed 35 °C; (3) If the membrane element is frozen, physical damage will occur, so take insulation measures and do not freeze it; (4) When stacking membrane components, do not exceed 5 layers and ensure that the carton remains dry. 2. Used membrane components (1) The membrane element must be kept in a dark place at all times, the storage temperature should not exceed 35 °C, and direct sunlight should be avoided; (2) There is a risk of freezing when the temperature is below 0 °C, so anti-freezing measures should be taken; (3) To prevent growth of the film is in the short-term standby element storage, transportation and microbial systems need to use pure water or reverse osmosis water prepared at a concentration 500 ~ 1,000ppm, sodium bisulfite pH3 ~ 6 (food grade) was protected Soak the components. (4) After immersing the membrane element in the preservation solution for about 1 hour, the membrane element is taken out of the solution and packaged in an oxygen barrier bag, and the bag is sealed and labeled to indicate the date of packaging; (5) After the membrane element to be preserved is repackaged, the storage conditions are the same as those of the new membrane element; (6) The concentration and pH of the preservation solution should be kept within the above range, and should be checked regularly. If it is possible to deviate from the above range, the preservation solution should be prepared again; (7) The film should not be allowed to dry under any circumstances. (8) Alternatively, a concentration (mass concentration) of 0.2 to 0.3% formaldehyde solution may be used as the preservation solution. Formaldehyde is a stronger microbial killer of Bismuth sulphate and contains no oxygen in the composition. Reverse osmosis system shutdown maintenance 1. Things to consider when saving are as follows (1) After shutdown, flush the system with treated reverse osmosis feed water, demineralized water or product water; (2) In order to maintain the performance of the system, the membrane element must remain wet at all times; (3) In order to prevent the growth of bacteria in the pressure vessel, disinfection is required; (4) If the membrane element is contaminated, system failure may occur, so chemical cleaning should be performed before storage to remove dirt from the membrane element and limit the growth of bacteria to a small possibility; (5) The allowable temperature and pH range for storage in a pressure vessel are as follows: temperature range: 0 to 35 ° C, pH range: 3-7 (6) The preservation solution is made of acidic sodium bisulfite (SBS) solution. The water in which the preservation solution is formulated must be free of residual free chlorine or other oxidizing agents. 2. Short-term storage (less than 48 hours) If the reverse osmosis system has a downtime longer than one day but less than two days, take the following steps to save the system: (1) Flush the system with RO water and remove the air from the system; (2) When the pressure vessel is filled with water, close the inlet and concentrate valves. Repeat the above steps every twelve hours . 3. Long-term preservation (more than 48 hours) If the reverse osmosis equipment has a downtime of more than 48 hours, the following procedures can be used to save the system: (1) Prior to all storage, the system needs to be cleaned to remove all contaminants and dirt deposited on the membrane surface prior to the long-term system shutdown, using the recommended standard cleaning procedures. After successful cleaning and disinfection, the storage should be carried out as quickly as possible, with a relatively close cleaning/disinfection time interval of 12 hours. (2) Storage is accomplished by cycling through a 500-1,000 ppm sodium bisulfite solution using a cleaning system. In this way, the membrane element will be thoroughly wetted in the preservation solution. In this way, the solution is circulated throughout the system, and after the completion of the secondary cycle (about 1 hour), the amount of remaining air can be reduced to a small extent. Make sure that the system does not contain air for sealing during storage and that it is air tight. (3) Close all valves on the supply and brine terminals. Any contact of the sodium bisulfite solution with outside air (oxygen) will cause sodium bisulfite to be oxidized to sulfate and the pH will continue to decrease. After all the bisulfite is consumed, the remaining oxygen will not be absorbed, and the state of the organism becomes unstable. (4) The pH of the stored reverse osmosis system needs to be adjusted periodically (at least once a month) to ensure that the pH of the solution does not fall below 3. If the pH of the preservation solution is found to be below 3, the preservation solution must be replaced. The preservation solution must be changed every month. (5) During shutdown, the storage temperature should not exceed 35 °C, but not below 0 °C to prevent freezing. (6) A formaldehyde solution having a mass percentage concentration of 0.2-0.3% may be used instead of sodium hydrogen sulfite as a preservation solution. Formaldehyde is a stronger microbial killer of Bisodium sulphate and contains no oxygen in its composition. Note: Since formaldehyde has certain toxicity, it is necessary to pay attention to the safety regulations for the use of formaldehyde when using formaldehyde. The membrane element must be used under normal conditions for at least 24 hours before being stored with formaldehyde solution, otherwise it may cause a large flow of water. reduce. Frozen Mussels,Frozen Cooked Clean Mussel Meat,Cooked Mussel Meat,Seafood Mussel Meat Shengsi Xiangyuan Aquatic Products Co.,Ltd., , https://www.mytilus-edulis.com