Thermodynamic Functions of the Solid-Liquid Transition of Hydrocarbon Mixtures

Abstract

The dependences of the melting temperature and the enthalpy of fusion on the composition are the essential factors for modelling precipitation and solubility of solid hydrocarbons in crude oils and crude oil products, Long-chain iso-alkanes and cyclic alkanes must be considered besides of n-alkanes. Therefore a degree of isomerization and cyclization was defined using the refractive index and the carbon number, The melting temperatures and the enthalpies of fusion of different n-alkanes and fractions of crude oil were determined by differential scanning calorimetry, Both parameters can be correlated with the degree of isomerization and cyclization by a quadratic fuction,

Influences on the Needle Penetration of Petroleum Wax

“…(1) with the crystallinity and the crystallization gradient in the range between 25 and 40 C did not show definite relations (Laux et al, 1999). (1) with the crystallinity and the crystallization gradient in the range between 25 and 40 C did not show definite relations (Laux et al, 1999).…”

“…The influence of crystallinity on the needle penetration of waxes had already been investigated in a previous paper (Laux et al, 1999). Starting point was the dependence of the needle penetration on temperature t according to Eq.…”

“…In order to consider the increasing crystallinity below 40 C, an additional crystallization gradient was introduced (Laux et al, 1999).…”

An investigation of the dependence of penetration on the temperature and composition of paraffin waxes

“…The coefficients a 0 and a 1 are product-specific parameters. The average melting temperature of the n-alkanes of the mixture (t m ) is calculated according to equation (2) [15] from the average carbon-number n c determined by GC (predicted value of the n-alkanes distribution).…”

“…The calculation of the melting enthalpy of the n-alkane mixture is according to Laux et al [15] to be carried out according to equation (4):…”