Correlation of mass transfer coefficient in the extraction of plant oil in a fixed bed for supercritical CO2

The estimation of mass transfer coefficients in supercritical fluid extractions for fixed bed systems has been investigated. Two types of correlations are discussed: Sh′ = m(Re1/2Sc1/3)n and Sh′=m(Ren1Scn2)Sh′=m(Ren1Scn2). Two statistical methods, the weighted least squares method and the error-in-variable-model (EVM), were used to estimate the model parameters based on published data, respectively. The linear least squares method is not suitable theoretically as the estimated error for Re1/2Sc1/3 is larger than the error of Sh′. The estimation result based on the data of Puiggene et al. was revised as Sh′ = 0.422(Re0.580Sc0.3074) when 10 < Re < 100. It shows consistent kinetic behavior in this region according to their data and it is also validated by the other literature data. The estimation also shows that it is acceptable to account the exponent of Sc as 1/3.