DuPont UF Membrane Ultrafiltration SFP2880 Performance Standard
Adopted by the International Association for the Nature of Water and Water Vapor (IAPWS, www.).iapws.org/relguide/liquidwater.htm) is the latest formula for calculating the viscosity of liquid water, resulting in a viscosity-temperature correction factor.
The formula for calculating the Temperature Correction Factor (TCF) is described in Equation 7-1
Wherein: TCF: temperature correction factor, dimensionless.
tk: Kelvin temperature (i.e.: +273.)15℃）。
The numerator of equation 7-1 is the dynamic viscosity of water at 25 in pa·s, and the denominator is the viscosity of water at the actual operating temperature. The formula calculates that the TCF at 25 is equal to 1.
Table 7-4 lists the different TCF values for every 5 increase in the range of 0 40 calculated according to Equation 7-1 above
Table 7-4Correspondence between temperature and TCF.
Figure 7-10 shows the correspondence between the TCF value and the temperature
Correspondence between TCF and temperature ( ).
Figure 7-10Correspondence between TCF and temperature ( ).
Equations 7-2 and 7-3 list the formulas used to calculate the standardized transmembrane differential pressure (TMP) and standardized permeability:
Normalized TMP (Bar) = Actual TMP x TCF (Equation 7-2).
Normalized permeability (LMH bar) = actual permeability tcf (Equation 7-3).
The permeability is the membrane flux (l m2·h) divided by the transmembrane pressure difference (bar) in l m2 h·bar, also expressed as lmh bar).
To illustrate the importance of data standardization, two case data from the ultrafiltration plant were analyzed: