Petroleum vanadium contents

Data from Ohtsuka (1977) on the demetallation of a Khafji feedstock are shown in Fig. 33. The vanadium content is reduced simultaneously with an increase in desulfurization, but the nickel is not removed until 60% desulfurization. This behavior is observed for the full crude as well as for two atmospheric residua cuts (180 and 310°C) indicating consistently higher vanadium reactivity throughout the molecular weight distribution of metal-bearing compounds in the petroleum. 

Distillation concentrates the metallic constituents in the residua (Table 3-5) some can appear in the higher-boiling distillates but the latter may, in part, be due to entrainment. Nevertheless, there is evidence that a portion of the metallic constituents may occur in the distillates by volatilization of the organometallic compounds present in the petroleum. In fact, as the percentage overhead obtained by vacuum distillation of reduced crude is increased, the amount of metallic constituents in the overhead oil is also increased. The majority of the vanadium, nickel, iron, and copper in residual stocks may be precipitated along with the asphaltenes by low-boiling alkane hydrocarbon solvents. Thus, removal of the asphaltenes with n-pentane reduces the vanadium content of the oil by up to 95% with substantial reductions in the amounts of iron and nickel. 

Vanadium is also found in crude petroleum oils levels range from 1 to 400 g/metric ton (Byerrum et al. 1974). Content in domestic oils range from 0.1 ppm in New Mexico to 78 ppm in Montana. Venezuelan crude oils are thought to have the highest vanadium content, ranging from 0.6 ppm in San Joaquin to 1,400 ppm in Boscan (Byerrum et al. 1974). 

The total amount of vanadium in residual fuel oil is probably greater than in any other product of petroleum refining. About 668 million barrels of fuel oil were consumed in the United States in 1968, and this material is estimated to have contained nearly 19,000 tons of vanadium. At the current price, this amount of vanadium is worth about 100 million. Desulfurization of fuel Oil can reduce the vanadium content about proportionate to the reduction of sulfur.If fuel oil is desulfurized to reduce atmospheric pollution, can a significant amount of vanadium be recovered profitably from the catalysts used in the desulfurizing process or at some other stage in this process ... 

Example 19 J. We wish to determine the element vanadium in a 1.00 g sample of petroleum. We anticipate the vanadium content to be about 100 ppm by weight. A Cf neutron source with a useful flux density of 2 x 10 n/(cm -sec) is available, along with a detector system with a total FEP efficiency of 10.0% for the 1.43-MeV gamma ray. The 1.43-MeV gamma rays are emitted in 100% of the disintegrations. Calculate the number of counts that would be obtained for V if the sample is irradiated to saturation and cooled for 2.00 min prior to counting for a period of... 

As a practical matter, the concentration of vanadium, nickel, and other inorganic matter in petroleum coke is largely a function of the source of the crude oil as is shown in Table 2.8. Sweet (low sulfur) crude oils not only contain less ash, but can ccmtain lower concentrations of vanadium, nickel, and other deleterious metals (see data from [4]). The vanadium content in the Venezuelan crude oil shown in Table 2.8 is particularly high, while the vanadium content in the Canadian crude oil is... 

Asphaltenes have high concentrations of heteroelements sulfur, nitrogen, nickel and vanadium. Their content varies widely in petroleum oils (Table 1.5). They cause a number of problems throughout the petroleum industry. 

The high-chromium casting alloys (50% nickel, 50% chromium and 40% nickel, 60% chromium) are designated for use at temperatures up to 900 C in furnaces and boilers Ared by fuels containing vanadium, sulfur and sodium compounds (e.g., residual petroleum products). Alloys with lower chromium contents cannot be used with residual fuel oils at temperature above 6S0 C because the nickel reacts with the vanadium, sulfur and sodium -impurities to form compounds that are molten above 650 C [27]. 

Although various carbonaceous sources can be used, petroleum cokes were preferred because of their low ash contents and generally higher yields of active carbon. The cokes were obtained from various sources and with widely varying properties. Sulfur contents ranged from 2.0 to 6.0 wt.% metals, primarily nickel and vanadium, from 500 ppm to 5,000 ppm volatile matter, from 11% to 20%. The coke quality within these ranges did not appear to affect active carbon properties. However, somewhat lower active carbon yields were noted with the higher volatile matter cokes (58-62 wt% vs. 

Using the Compton line of the tube as an internal standard reference sometimes enables a thorough correction of the matrix effects. This is illustrated by the analysis of trace elements Ni and V in petroleum products where the sulphur content is variable. Whilst, in the absence of sulphur, the matrix is extremely light and thus not particularly absorbent, an increase in sulphur content leads to a noticeable absorption of the Ni and V signals. The first curve in Figure 4.11 is plotted from net intensity levels measured on vanadium, whereas, in the lower curve the net V K. intensity levels have been replaced by the intensity ratios ... 

One of the properties of fossil fuels of interest to refiners is metal content. Vanadium in particular is troublesome in refinery operations (2). In some crude oils it occurs in concentrations up to 1000 ppm (3). Of the other metals in petroleum, only nickel is known to be present in concentrations approaching that of vanadium. These two metals are com-plexed with porphyrins and other ligands, the exact nature of which is unknown (4), Crude oils that are high in sulfur are usually high in vanadium (5), and it is interesting to determine whether or not this criterion also applies to tar sands. 

Combustion of the mixed oils may generate less pollutant compounds such as NO, PAH and SO, . The hot corrosion caused by the vanadium contained in the usual gas turbine fuel might also be inhibited by the presence of some metals contained in the biofuels [17]. The sulphur content of the mixed oils is expected to be lower than that of conventional petroleum friels. 

The first two of these compounds occur at sufficiently high concentrations in some crudes to enable production of them from petroleum. Benzonitrile has also been detected [6]. Much of the trace metal content of petroleums, in particular vanadium and nickel, is present in association with petroporphy-rins, which are polycyclic pyrroles closely related in structure to the hemes and chlorophylls. These materials are examples of the more complex nitrogen heterocycles to be found in petroleum. These particular heterocycles with their complexed metal atoms contribute much to our present knowledge of the original biogenesis of the petroleum hydrocarbons [6]. 

Petroleum coke is used principally as a fuel or, after calcining, for carbon electrodes. The feedstock from which the coke is produced controls the coke properties, especially sulfur, nitrogen, and metal content. A concentration effect tends to deposit the majority of the sulfur, nitrogen, and metals in the coke. Cokes exceeding about 2.5% sulfur content and 200 ppm vanadium are mainly used, environmental regulations permitting, for fuel or fuel additives. The properties of coke for non-fuel use include a low sulfur, metal, and ash content as well as a definable physical structure. 

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