The easiest way to predict the desalination rate of the system is to perform actual calculations through the calculation software of the membrane element manufacturer. After understanding the relationship between the standard desalination rate of membrane elements, the actual desalination rate and the system desalination rate, when designing reverse osmosis devices, providing users with system performance guarantees, checking and accepting reverse osmosis devices, or evaluating membrane element performance, it must be based on the actual system. The salt rejection rate can not be carried out at the standard salt rejection rate of the membrane element.
The standard desalination rate of reverse osmosis membrane elements is the desalination rate measured by the membrane element manufacturer under standard conditions. Taking Hydenergy’s low-pressure products as an example, the minimum desalination rate of CPA2 under standard conditions is 99.2% (average desalination rate) It is 99.5%), the lowest salt rejection rate of CPA3 under standard conditions is 99.6% (average salt rejection rate is 99.7%).
The actual desalination rate of the membrane element is the desalination rate of the membrane element in actual use. The actual desalination rate is sometimes higher than the standard desalination rate, but in most cases it is lower than the standard desalination rate. This is due to the standard test conditions and actual The conditions of use are completely different. Under standard test conditions, the standard test solution is sodium chloride solution, and the standard salt rejection rate of the membrane element is the removal rate of sodium chloride. In actual use conditions, due to the different ion components in the water, the temperature, the average water flux selection value, and the system recovery rate are different from the standard test conditions, and these factors will affect the salt rejection rate of the membrane element.
The desalination rate of the system is the desalination rate shown by the complete set of reverse osmosis devices. Also due to the different use conditions and standard conditions, the desalination rate of the system is different from the standard desalination rate. At the same time, because the reverse osmosis device generally has multiple membrane elements in series, and the device The actual use conditions of each membrane element are different, so the system desalination rate is also different from the actual desalination rate of the membrane element. For a device with only one membrane element, the system desalination rate is equal to the actual desalination rate of the membrane element.