New restrictions on vaporization loss os petroleum products give added emphasis to the measurement of vapor pressure for petroleum fractions and their blends. The common method for measuring vapor pressure is the Reid vapor pressure (Rvp) test. Now an algorithm is available to calculate Rvp without performing the actual test. The algorithm, based on air-and-water free model, uses the Gas Processors Association Soave-Redlich-Kwong equation of state and assumes liquid and gas volumes are additive. Since the calculations are iterative, they are incorporated into a general purpose process simulator to compare predicted values with experimental data. Good agreement is found between predicted and experimental values. Furthermore, the algorithm is fast and can be used to predict Rvp of any hydrocarbon mixture of known composition.

Seven unweathered heavy residual oils, analyzed and compared for source identification purposes, demonstrate that the comparison of heavy residual oils must be performed with great care using a variety of analytical techniques and comparison methods. Furthermore, these methods are best applied to known common-source pairs and to known non-common-source pairs in addition to the unknown pairs. Physical and chemical tests showed that, for the most part, these properties for the seven oils were within the error range of the test. Visual comparison of the chromatograms also showed that they were very similar. Normalized normal paraffin and isoprenoid peak height profiles, when subjected to measurement-error and statistical comparisons, provided quantitative evaluations of the relative likelihood that the members of the various oil pairs were from a common source.

Precipitation of solids is one of the major problems associated with the shipping and handling of heavy residual oils especially No. 6 heating oil. ASTM specifications which currently include viscosity, flash point and pouring point are not adequate to predict the handling problems. The residual oils are becoming more complex in composition due to modern refinery techniques for cracking the heavier residues into distillable fractions. In this study, several heating oil samples, including a sample which partially solidified during transport, were analyzed using various techniques including separation by gel permeation chromatography (GPC), vacuum distillation, separation of petroleum asphaltenes by ASTM method, elemental analysis and proton and 13C NMR spectroscopy. The distillable species in the fraction separated by GPC were characterized by high resolution gas chromatography-mass spectroscopy (GC-MS). The study showed that the GPC can be used as a reliable technique for the analysis of heavy residual oils. The GPC separation of No. 6 heating oil gave three fractions enriched with chemically distinct asphaltenes. The second fraction was mostly straight chain paraffins. The third fraction was composed of low molecular weight aromatics. Although occasional verification of GPC data by GC-MS and by NMR spectroscopy is desirable, the GPC alone is an efficient analytical tool for evaluating the composition as well as predicting the handling problems associated with shipping and storage of various residual oils.

A severe case of incompatibility occurred when three residual fuel oils were shipped as a blend. The oils were blended as they were being loaded. During transport, a tar-like precipitant formed, settled to the bottom and partially solidified. These fuel oils were analyzed in an attempt to predict future potential incompatibility problems and to investigate the known case of incompatibility.