Residual fuels consumption

In the United States, the largest concentration of atmospheric vanadium occurs over Eastern seaboard cities where residual fuels of high vanadium content from Venezuela are burned ia utility boilers. Coal ash ia the atmosphere also coataias vanadium (36). Ambient air samples from New York and Boston contain as much as 600—1300 ng V/m, whereas air samples from Los Angeles and Honolulu contained 1—12 ng V/m. Adverse pubHc health effects attributable to vanadium ia the ambieat air have aot beea deteroiiaed. lacreased emphasis by iadustry oa controlling all plant emissions may have resulted ia more internal reclamation and recycle of vanadium catalysts. An apparent drop ia consumption of vanadium chemicals ia the United States since 1974 may be attributed, in part, to such reclamation activities. 

All of the world s major economies, as well as scores of smaller, low-income nations, rely mainly on hydrocarbons. Crude oil now supplies two-fifths of the world s primary energy (Table 1). There are distinct consumption patterns in the shares of light and hea vy oil products the United States burns more than 40 percent of all its liquid fuels as gasoline, Japan just a fifth and the residual fuel oil accounts for nearly a third of Japanese use, but for less than 3 percent of the U.S. total. Small countries of the Persian Gulf have the highest per capita oil consumption (more than 5 t a year in the United Arab Emirates and in Qatar) the U.S. rate is more than 2.5 t a year European means arc around 1 t China s mean is about 120 kg, and sub-Saharan Africa is well below 100 kg per capita. 

U.S. consumption of distillate fuels used for heating decreased gradually between 1979 and 1983 (lARC 1989). The annual domestic demand for distillate fuel oils was approximately 1,214,355,000 barrels in 1979, decreasing to 981,850,000 barrels in 1983. The U.S. demand for distillate fuels subsequently rose from 1984 to 1989, reaching an annual maximum of 1,248,700,000 barrels in 1989 (API 1991). The annual domestic demand for residual fuel oils also decreased between 1979 (1,034,800,000 barrels) and 1985 (475,600,000 barrels). After 1985, the demand varied from an annual average of 561,000,000 barrels in 1986 to 486,180,000 barrels in 1990 (API 1991). Finally, the average annual domestic demand for kerosene decreased from 68,990,000 barrels in 1979 to 16,790,000 barrels in 1990 (API 1991). 

Another source of metallic contamination in the studied region comes from the residual oil combustion used for electric utilities and fluvial and terrestrial transportation. Using the selected emission factors (quantity of trace element released by quantity of material consumed) given by Nriagu and Pacyna (1988) and Nriagu (1989), the electric-power production installed in the Amazonian states and the fuel consumption used for transportation (Ministerio de Minas... 

Populations in areas with high levels of residual fuel oil consumption may also be exposed to above background levels of vanadium, both from increased particulate deposition upon food crops and soil in the vicinity of power plants and higher ambient air levels (Zoller et al. 1973). Cities in the northeastern United States frequently fall into this category, where ambient air levels often range from 150 to 1,400 ng/m (Zoller et al. 1973). 

The advantages of this system are lower fuel consumption and lower cost in comparison with the closed-cycle layout, which must be gastight. It is used, for example, in the pharmaceutical industry for drying of fermentation residues. 

The increase in demand for good quality white products and the reduced consumption of fuel-oil related to pollution controls are going to be important factors in residue processing and heavy oil conversion in the years to come. 

The growth of petroleum consumption has been quite substantial as a result of increasing demand for its distillation products. As examples, mention may be made of use of gasoline as a motor fuel, of light oil for diesel engines, of distillate and residual oils for industrial and domestic heating. 

For a given energy consumption, fuel change is the only way to reduce C02 and SO emissions at source. Fuel switch from, say, coal to natural gas reduces the C02 emissions for the same heat release because of the lower carbon content of natural gas. Fuel change can also be useful for reducing NO, emissions. Once emissions have been minimized at source, then treatment can be considered to solve any residual problems. 

Both in the USA and the EU, the introduction of renewable fuels standards is likely to increase considerably the consumption of bioethanol. Lignocelluloses from agricultural and forest industry residues and/or the carbohydrate fraction of municipal solid waste (MSW) will be the future source of biomass, but starch-rich sources such as corn grain (the major raw material for ethanol in USA) and sugar cane (in Brazil) are currently used. Although land devoted to fuel could reduce land available for food production, this is at present not a serious problem, but could become progressively more important with increasing use of bioethanol. For this reason, it is important to utilize other crops that could be cultivated in unused land (an important social factor to preserve rural populations) and, especially, start to use cellulose-based feedstocks and waste materials as raw material. 

Based on currently proven energy plantation area In Ontario of about 500,000 hectares and poplar yields of about 9 oven-dry tonnes per hectare per year (about 4 oven-dry tons per acre per year) plus about one million tonnes per year of wood residues. These feedstock quantities would produce about 2-3% of the total petroleum consumption. Some additional production is possible by expansion of the energy plantation area. (An additional one and one-half million hectares would increase the percentage liquid fuel production to about 8-10%.)... 

When one considers the early 2000 s, it can be expected that about one half of the thermal energy will be supplied by natural gas, and the rest by petroleum fuels (fuel oil and residual oil) and coal. Coal is assumed to be the main energy source for electricity generation, gasoline for surface transportation, and jet fuel for air transportation. This is of course a simplified version of the fossil fuel energy system, but it is close enough to the present patterns of energy consumption, and can be used as the basis for comparisons. 

Direct liquefaction processes under development are typically carried out at temperatures from about 450 to 475°C and at high pressures from 10 to 20 MPa and up to 30 MPa. Despite the slow rate at which liquefaction proceeds, the process itself is thermally rather efficient, since it is only slightly exothermic. However, hydrogen must be supplied and its manufacture accounts for an important fraction of the process energy consumption and cost of producing the liquid fuel. The hydrogen itself may be produced, for example, by the gasification of coal, char, and residual oil. 

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