Patent ID: 6841779

Claim:
A method of determining wax precipitation temperature (WPT) for a liquid hydrocarbon sample, the method comprising: Measuring infra-red light absorbance of the sample, The measuring made at a plurality of temperatures at a same wave number to obtain a plurality of data points of total absorbance (A TOTAL ) vs. temperature (T), the wave number corresponding to a wavelength at which the infrared light is absorbed by long chain methylene on a molecule, calculating by a linear regression a slope (S S ) of A TOTAL vs. T from the data points in which a solid phase is apparent and are data points below the WPT, calculating by a linear regression a slope (S L ) of A TOTAL vs. T from the data points in which the sample is essentially free of a solid phase and are data points above the WPT, calculating the temperature which is at the intersection of lines A TOTAL =T*S S and A TOTAL =T*S L , which temperature is the determined wax precipitation temperature.