Kesler

The critical compressibility factor is estimated using the Lee and Kesler equation (1975) ... 

For heavy fractions whose boiling temperatures exceed 600 K, it is better to use the method published by Lee and Kesler in 1975 ... 

Riazi s method applies to fractions whose specific gravities are less than 0.97 and whose boiling points are less than 840 K. The Lee and Kesler method is applicable for fractions having molecular weights between 60 and 650. 

We will use the method established by Lee and Kesler in 1975 because it is related to the calculation of thermal properties method we have selected and will discuss later. 

These should form a uniform group. Among several that have been proposed, we will use only those of Lee and Kesler (1975). 

If the vapor pressure is of interest, the acentric factor is calculated by the Lee and Kesler formula or by the Soave method, which are given in article 4.5.2. 

To calculate the heat of vaporization, the Lee and Kesler method in article 4.3.1.3 is used. 

To avoid confusion, the only acentric factor that we will use is that employed to find the boiling point by the Lee and Kesler method. 

For reduced temperatures higher than 0.98, a second type of method must be used that is based on an equation of state such as that of Lee and Kesler. 

The isobaric specific heat for a petroleum fraction is estimated by a correlation attributed to Watson and Nelson in 1933, which was used again by. Johnson and Grayson in 1961 as well as by Lee and Kesler in 1975. This relation is valid at low pressures i... 

When the reduced temperature is iess than 0.85, d(T depends very little on pressure. Table 4.8 gives values for and for enthalpy correction factorsi calculated by the Lee and Kesler method. 

The reduced correction for enthalpy employed in the preceding equation is obtained by the Lee Kesler model ... 

Hydrocarbon mixtures are most often modeled by the equations of state of Soave, Peng Robinson, or Lee and Kesler. 

The average accuracy of the Lee and Kesler model is much better than that of all cubic equations for pressures higher than 40 bar, as well as those around the critical point. 

The Lee and Kesler method for calculating densities is given in article 4.3.1.1 its average accuracy is about 1%, when the pressure is less than 100 bar. 

The Cpg of real gas is calculated using the equation derived from the Lee and Kesler model ... 

M = molecular weight dCp = reduced Cp correction calculated fromthe Lee and Kesler model From a practical point of view, as for liquids, it is possible to calculate dC... 

When the critical constants for a pure substance or the pseudocritical constants for a petroleum fraction are known, the vapor pressure for hydrocarbons and petroleum fractions can be calculated using the Lee and Kesler equations ... 

This method is based on the expression proposed by Lee and Kesler in 1975. It applies mainly to light hydrocarbons. The average error is around 2% when the calculated vapor pressure is greater than 0.1 bar. 

Soave m coefficient Solubility parameter at 25°C Temperature 3 °c Interfacial tension at 73 mN/m Lee Kesler acentric factor... 

There are a number of reliable estimating techniques for obtaining pure-component hq uid heat capacity as a function of tem )erature, including Ruzicka and Dolmalsld, Tarakad and Danner, " and Lee and Kesler. These methods are somewhat compheated. The relatively single atomic group contribution approach of Chueh and Swanson for liquid heat capacity at 29.3.15 K is presented here ... 

Note that use of the Lee-Kesler fit [Eq. (2-78)] would give a slightly more accurate answer than the graphical method, and this fit is used for any computer applications. 

Lee and Kesler fit the entire Pitzer method to equations, rewriting the basic Eq. (2-75) with respect to a heavy reference fluid (n-octane) as shown by Eq. (2-78). 

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