Hayduk

For estimating the diffusivity of the dilute solute (10 mole percent) in water, the method of Hayduk and Laudie, Eq. (2-159), applies. 

Hayduk-Laudie They presented a simple correlation for the infinite dilution diffusion coefficients of nonelectrolytes in water. It has about the same accuracy as the Wilke-Chang equation (about 5.9 percent). There is no explicit temperature dependence, but the 1.14 exponent on I compensates for the absence of T in the numerator. That exponent was misprinted (as 1.4) in the original article and has been reproduced elsewhere erroneously. 

Siddiqi-Lucas These authors examined 658 aqueous liqiiid mixtures in an empirical study. They found an average absolute deviation of 19.7 percent. In contrast, the Wilke-Chang equation gave 35.0 percent and the Hayduk-Laudie correlation gave 30.4 percent. 

Dilute Binary Hydrocarbon Mixtures Hayduk-Minhas presented an accurate correlation for normal paraffin mixtures that was developed from 58 data points consisting or solutes from C5 to C32 and solvents from C5 to Cig. The average error was 3.4 percent for the 58 mixtures. 

Hayduk, W., ed. (1996). Propane, Butane and 2-Methylpropane. New York Pergainon Press. 

The molecular diffusion coefficients in hquid phase can be estimated from the correlations of WiUce and Chang [47] for organic solutions and Hayduk and Minhas [48] for aqueous solutions, respectively. An extensive comparison of the available correlations is provided by Wild and Charpentier [49]. 

A number of approaches have been suggested for the determination of the molecular diffusion coefficient, D, of a component in water (Othmer and Thakar, 1953 Scheibel, 1954 Wilke and Chang, 1955 Hayduk andLaudie, 1974 Thibodeaux, 1996). Based on these five references, the diffusion coefficient ratio />/Jl2s / Dlq2 was found to vary within the interval 0.78-0.86 with an arithmetic mean value equal to 0.84. This value can be inserted in Equation (4.22) as a first estimate to determine Km. Equation (4.22) and the empirical expressions for KLC>2 outlined in Table 4.7 are the basis for the determination of the mass transfer coefficient for H2S, KL i S, and thereby, the emission of H2S from the wastewater into the sewer atmosphere. Further details relevant in this respect are dealt with in Section 4.4. 

Diffusion coefficients may be estimated using the Wilke-Chang equation (Danckwerts, 1970), the Sutherland-Einstein equation (Gobas et al., 1986), or the Hayduk-Laudie equation (Tucker and Nelken, 1982), which state that Dw values decrease with the molar volume (Vm) to the power 0.3 to 0.6. Alternatively, the semi-empirical Worch relation may be used (Worch, 1993), which predicts diffusion coefficients to decrease with increasing molar mass to the power of 0.53. These four equations yield very similar D estimates (factor of 1.2 difference). Using the estimates from the most commonly used Hayduk-Laudie equation... 

Very few experimentally determined diffusivities of organic substances in water are available in the documented literature. If experimentally determined diffusivity values are not available, Hayduk and Laudie (1974) recommend the following equation for estimating this parameter ... 

Hayduk, W. and Laudie, H. Prediction of diffusion coefficients for nonelectrolytes in dilute aqueous solution, Am. Inst. Chem. Eng., 20(3) 611-615, 1974. 

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