Document Type


Date of Award


Degree Name

Master of Science in Chemical Engineering - (M.S.)


Chemical Engineering and Chemistry

First Advisor

Donald G. Lambert

Second Advisor

Robert G. Poetz

Third Advisor

Avner Shilman


Forty-eight inference equations are presented to approximate the hydrocarbon composition of middle distillate fuels and of the solids separating from these fuels at temperatures below their cloud points by consideration of fuel physical inspections. The physical inspections consist of API gravity, aniline point, cloud point, and distillation curves for ten fuels from major United States and European refineries. To determine the percentage of solids separating from cooled fuels, each fuel is filtered over a temperature range from the cloud point to -40 F in 10 F increments. Aromatic, naphthenic, and paraffinic hydrocarbon contents and the r-paraffin carbon number distributions of the fuels and separated solids are determined using gas chromatography and mass spectroscopy. Hydrocarbon composition variables are correlated with physical inspection variables by stepwise, linear multiple regression analyses using the method of least squares.

Aromatic, naphthenic, and paraffinic hydrocarbon contents average 33, 32, and 38 wt.%, respectively, and are approximated successively from aniline point and volumetric average boiling point date. The n-paraffin contents average 19 wt.%, separate at approximately 0.2 wt.%/ F and constitute an average 81 wt.% of the solids separated from fuels cooled to -20 F; the median and semi-interouartile range of the carbon number distributions at this temperature average 18 and 1.2, respectively, versus values of 15 and 2.3, respectively, for the total n-paraffins in the fuels. Then-paraffin separation characteristics are approximated from cloud point and distillation data.

The relative concentrations of aromatic, naphthenic, and paraffinic hydrocarbons indicate combustion quality and subsequent smoke emission. The n-paraffins separating from cooled fuels can form immobilizing matrices. Thus, the forty-eight inference equations provide a systematic approach to the problems of smoke emission and low temperature operation.



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