The Effects Of Operation Parameters On Separation Performance Of RO And Parameter Analysis Of Transfer-model

The effects of operation parameters on flux of permeate and Mg²⁺ rejection were tested in this work, and on boundary of inlet water characteristic, the coefficient analysis of the qualitative transfer-model was taken on the basis of non-balance thermodynamics model, in addition, a quantitative transfer-model was developed by using the method of linear regression.The factors influencing separation performance of the membrane were operating pressure, temperature of experiment, concentration of feed solution, and velocity of flow. The research was carried out with the orthogonal experiment of 16 different condition levels. The experimental results show that operating pressure and temperature of experiment are two very prominent factors influencing flux of permeate, the value of F respectively is 21.55 and 21.17. Velocity of flow also has influence on flux of permeate, the value of F is 5.09. The change of concentration of feed solution has little influence on flux of permeate, the value of F is only 1.28. The prominent factor influencing rejection is temperature of experiment, F=7.44. The effects of other factors are not so significant, for operating pressure, velocity of flow as well as concentration of feed solution, the value of F respectively is 4.33, 3.74 and 1.81.By analyzing and summarizing various transfer-models of RO, and in terms of non-balance thermodynamics model, a new parameter was advanced: the solution permeance coefficientψ, and a qualitative transfer-model was developed and proved by 16 groups of data of the orthogonal experiment. First, the model constants were determined from a group of data, and then, according to these constants and transfer equations of the model develope, the flux of permeate of the rest 15 experiments could be calculated. Comparing with the experimental flux of membrane, it is shown that the values calculated are accurate. The minimum relative error is of 0.42% and the mean-root-square error is of 7.98%.The inlet water characteristic was considered as a constant on condition of using tap water as resource in the RO experiment. Consequently, we get a quantitative transfer-model by using the method of linear regression to deal with the 25 groups of data of the RO experiment, and taking a series of significance testings. It is shown that the values of the flux of membrane calculated through the quantitative transfer-model are quite accurate as to forecasting the flux of membrane. The minimum relative error is of 0.107% and the mean-root-square error is only of 2.50%.