Vanadium fossil fuel

A high-nickel alloy is used for increased strength at elevated temperature, and a chromium content in excess of 20% is desired for corrosion resistance. An optimum composition to satisfy the interaction of stress, temperature, and corrosion has not been developed. The rate of corrosion is directly related to alloy composition, stress level, and environment. The corrosive atmosphere contains chloride salts, vanadium, sulfides, and particulate matter. Other combustion products, such as NO, CO, CO2, also contribute to the corrosion mechanism. The atmosphere changes with the type of fuel used. Fuels, such as natural gas, diesel 2, naphtha, butane, propane, methane, and fossil fuels, will produce different combustion products that affect the corrosion mechanism in different ways. 

Vanadium leaches soil from a large number of diverse sources, including waste effluents from the iron and steel industries and chemical industries. Phosphate industries are also a major source of vanadium pollution because vanadium becomes soluble along with phosphoric acids when rock phosphates are leached with sulfuric acid. Vanadium is present in all subsequent phosphoric acid preparations, including ammonium phosphate fertilisers, and is released into the environment along with them. Other sources of vanadium pollution are fossil fuels, such as crude petroleum, coal and lignite. Burning these fuels releases vanadium into the air, which then settles in the soils. 

Humans have been exposed more and more to metallic contaminants in the environment, mostly from the products of industry. There are three main sources of metals in the environment. The most obvious are the processes of extraction and purification mining, smelting, and refining. Another is the release of metals from fossil fuels (e.g., coal, oil), when these are burned. Cadmium, lead, mercury, nickel, vanadium, chromium, and copper are all present in these fuels, and considerable amounts enter the air or are deposited in ash. The third and most diverse source is the production and use of industrial products containing metals, which is increasing as new applications are found. The modem chemical industry, for example, uses many metals or metal compounds as catalysts metal compounds are used as stabilizers in the production of many plastics, and metals are added to lubricants, which then find their way into the environment.21... 

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. 

Vanadium was discovered in 1830. It is present at 0.01% in earth s crust. Vanadium is released naturally into the air through the formation of continental dust, marine aerosols, and volcanic emissions. The natural release of vanadium into water and soils occurs primarily as a result of weathering of rocks and soil erosion. Anthropogenic sources include the combustion of fossil fuels, particularly residual fuel oils, which constitute the single largest overall release of vanadium to the atmosphere. Deposition of atmospheric vanadium is also an important source... 

Elemental vanadium does not occur in nature however, vanadium compounds exist in over 50 different mineral ores and in association with fossil fuels. It has six oxidation states (1- 0, 2+, 3+,... 

Vanadium is a white to gray metal with compounds widely distributed at low concentrations in the earth s crust. The average concentration of vanadium compounds in the earth s crust is 150 mg/kg. Elemental vanadium does not occur in nature, but its compounds exist in over 50 different mineral ores and in association with fossil fuels. It has six oxidation states (1-, 0, 2+, 3+, 4+, and 5+) of which 3+, 4+, and 5+ are the most common. The ion is generally bound to oxygen. 

Fossil fuels frequently contain vanadium. Vanadium is found in almost all coals used in the United States, with levels ranging from extremely low to 10 g/kg (Byerrum et al. 1974 WHO 1988). Eastern U.S. coal has an average content of 30 ppm, western coal has an average content of 15 ppm, and coal from the interior contains an average of 34 ppm (Byerrum et al. 1974). The average vanadium content of bituminous and anthracite coal is 30 ppm and 125 ppm, respectively (Byerrum et al. 

Another source of vanadium, of interest in biological and environmental contexts, are fossil fuels such as peat, coal, bitumen, oil-shales, asphalts and crude oil. The vanadium content of hard coal can vary from 0.007 to 0.34%. Crude oil from Albania (0.034%), the Volga-Ural region (0.061%) and Venezuela (0.12%) (upper limit in all three cases) is particularly rich in vanadium.I l A high vanadium content is often associated with high sulfur contents. The reasons for the notable enrichment of vanadium in fossils compared with bio-mass precursors such as bacteria, protozoans, algae, plants and animals are still under debate. Possible mechanisms for a secondary input of vanadium in decaying... 

Vanadium was discovered in 1802/1803. The current annual world production of V2O5 is 35 000 tons, the majority of which is used in steel production. Small amounts of the element also occur in fossil fuels (Bauer et al. 2002, Tissot and Welte 1984). 

Small amounts of vanadium also occur in fossil fuels from Venezuela, California, Iran, Iraq, and Kuwait (10mgL in the Middle East to 1000 mg L in Central America), Indonesian, Libyan and West African oils contain but negligible amounts of vanadium (Tissot and Welte 1984). The vanadium is concentrated in the ash when these fuels are burned, between a few percent and 40%. The total amounts greatly exceed current consumption. 

Bertine and Goldberg (27) have shown that the rate of mans mobilization of vanadium (considering only fossil-fuel combustion) is far smaller than that of natural processes as measured by the outflow rate... 

The detrimental effects of particulate matter on the atmosphere have been of some concern for several decades. In fact, the total output of particulate matter into the atmosphere has increased in Europe since medieval times (Brimblecombe, 1976), and, although the sources are various, there is special concern because of the issue of particulate matter from fossil fuel use (Cawse, 1982). Species such as mercury, selenium, and vanadium, which can be ejected into the atmosphere from fossil fuel combustion (Kothny, 1973 Lakin, 1973 Zoller et al., 1973), are particularly harmful to the flora and fauna mercury. Thus, there is the need to remove such materials from gas streams that are generated during fossil fuel processing. 

Environmental studies [17] of urban airsheds in several areas of the country have shown that high levels of atmospheric vanadium oxide are associated with industrialized areas, especially those areas where fossil fuels are burned or where vanadate steel is being produced. In addition, vanadium has been shown to exhibit increased tissue levels in fish and other marine animals associated with oil rigs in the Santa Barbara basin of the United States [18]. Blotcky et al. [19] determined the vanadium content in shrimp, crab, and oyster from four ocean sites off and near Galveston Island, Texas. They found that the vanadium content was greater in marine biological samples taken in waters near industrialized areas as compared to samples taken in waters near the nonindustrialized sections. Speciation of the vanadium is very important since the two oxidation states, i.e., IV or V, have different nutritional and toxic properties [14]. Orvini et al. [20] applied a preirradiation speciation method to freshwaters from the Italian Ticino and Po rivers and found out that vanadium was present in various tetravalent cationic and pentavalent anionic as well as in natural complexed forms. 

Service testing to simulate ash/salt deposit corrosion is of importance to a number of industries. The fossil-fired power generation industry must deal with what is called "fuel ash corrosion fixrm sulfur- and vanadium-containing fuels and alkali, chlorine, and sulfur in coal. The gas turbine industry must deal with "hot corrosion" problems arising fixjm sulfur in fuel and sodium salts from ingested air. Waste incineration environments can become even more complex with refuse containing sulfur, chlorine, phosphorus, and numerous metallic elements. 

The combustion of fossil fuels, particularly coal, generates large quantities of solid by-product, fly ash, blown out of furnaces with combustion gas. The best way to deal with fly ash is to not make it, but that is not possible for most commonly used combustion processes with fuels other than ashfree natural gas. Petroleum fuels produce much less fly ash than coal, but the petroleum fractions that are burned are the heavier ones containing ash-generating mineral matter. One special case is that of vanadium-rich Venezuelan crude oils that release an ash rich in vanadium oxide. 

The importance of toxic elements in environmental chemistry is rarely questioned, but a relatively small number of elements (mercury, lead, and cadmium) have received a large share of researchers attention. The environmental chemistry of the transition metals, e.g., chromium, nickel, manganese, cobalt, copper, etc., has also been investigated principally because of their roles in metabolism, especially enzymatic processes. However, two non-metals, arsenic and selenium, and two metals, beryllium and vanadium, are elements which will become more significant in the future from environmental and toxicological points of view. Arsenic and selenium have been investigated, but much more work is needed because of the importance of these two elements in the environment. The author considers beryllium and vanadium to be problem metals of the future . The primary exposure route for both beryllium and vanadium is via the atmosphere and as lower environmental standards are imposed, more uses are found for each element, and more fossil fuels (source of V) are burned, the amounts added to the atmosphere will have more significance. 

The testing demonstrated that cofiring petroleum coke with coal at Paradise Fossil Plant reduced the concentrations of mercury, chromium, lead, zinc, and cadmium in the fuel fed to the boiler [28]. The only metals exhibiting a significant increase in concentration in the fuel blend were vanadium and nickel. Because of the increase in concentration of vanadiiun and nickel, attention was given to the consequent partitioning and speciation of these metals found in abundance in the petroleum coke. Vanadium and nickel concentrations... 

---