| Description |
Fe, Ni, and V are considered trace impurities in heavy crude oils and tar sand bitumens. These metals are important in the petroleum industry, particularly because they are deleterious to petroleum upgrading catalysts and present potential biomarkers and diagenesis indicators. In order to understand the importance of these metals, we have examined several properties: 1) bulk metals levels, 2) distribution in separated fractions, 3) size behavior in feeds and during processing, 4) speciation as a function of size, and 5) correlations with rheological properties. Some of the results of these studies show: 1) V and Ni have roughly bimodal size distributions, 2) groupings were seen based on location, size distribution, and Ni/V ratio of the sample, 3) Fe profiles are distinctively different, having a unimodal distribution with a maximum at relatively large molecular size, 4) Fe concentrations in the tar sand bitumens suggest possible fines solubilization in some cases, 5) SARA separated fractions show possible correlations of metals with asphaltene properties suggesting secondary and tertiary structure interactions, and 6) ICP-MS examination for soluble ultra-trace metal impurities show the possibility of unexpected elements such as U, Th, Mo, and others at concentrations in the ppb to ppm range. |
