Properties of fuels

The use of gross calorific values or net calorific values (which assume that the water of combustion is present as vapour) plus the assumed value of coal leads to different coal to oil ratios being quoted in the literature, e.g. 1.5 1 to 1.7 1 by different authorities . The composition of natural gas varies widely in different parts of the world leading to different calorific values. North Sea gas contains about 90% methane and has a typical calorific value of 52 GJ per tonne. 

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The increase in fuel viscosity with temperature decrease is shown for several fuels in Figure 9. The departure from linearity as temperatures approach the pour point illustrates the non-Newtonian behavior created by wax matrices. The freezing point appears before the curves depart from linearity. It is apparent that the low temperature properties of fuel are closely related to its distillation range as well as to hydrocarbon composition. Wide-cut fuels have lower viscosities and freezing points than kerosenes, whereas heavier fuels used in ground turbines exhibit much higher viscosities and freezing points. 

Properties of Fuel Oxygenates and Other Fuel Constituents... 

FIGURE 24.2 Physical properties of fuel oxygenates relative to benzene. (Adapted from U.S. EPA, Technologies for Treating MTBE and Other Fuel Oxygenates, EPA 542-R-04-009, United States Environmental Protection Agency, Washington, DC, May 2004.)... 

The optimization of the formulation of fuels. ANNs can be used to develop relationships between the chemical composition of fuels and their performance, thus allowing the prediction of the properties of fuels that have yet to be formulated in the laboratory or tested in the field. 

Source Adapted from Alternative Fuels Data Center, Properties of Fuel, DOE Report, August 2005, available at www.afdc.doe.gov/fuel comp.html, April 2007. 

DOE 2003. Alternative fuel data center, Properties of Fuels, available at www.afdc.doe.gov/ pdfs/fueltable.pdf, 2007. 

Several methods have been investigated to find correlations between physical properties of fuel gas mixtures and the excess air ratio to optimize the combustion procedure. In spite of the varying composition of natural gas it is said to be possible to control a heater system by measurements of the dynamic viscosity of the gas [7]. One explanation could be the correlation between Wobbe number and viscosity With increasing Wobbe numbers the viscosity decreases, and if the Wobbe number of a gas is known, the excess air ratio can be adjusted, resulting in an open loop control. 

Due to the important relationship between particle size of starting powders and resulting electrode microstructure and corresponding performance, much work has been performed to modify the particle size and morphology of the starting powders used in SOFC processing. Additional methods have been investigated to better control the microstructure and properties of fuel cell components, which are discussed in more detail in Section 6.2. 

As shown above, CN and ON are important properties of diesel and gasoline fuels, respectively. Although a set of large databases are available, cetane and octane values of many individual compounds are still missing. Therefore, the prediction tools we have developed are very useful in correlating the molecular structures with properties of fuels. In this section, the predicted CN and ON values are implemented to construct the most effective catalytic strategies to optimize CN for diesel and ON for gasoline. 

In this profile, fuel oils are discussed together because of the similarities in their chemical and physical properties. More information on the chemical and physical properties of fuel oils is provided in Chapter 3. More information on the production and use of fuel oils is found in Chapter 4. 

Information regarding the physical and chemical properties of fuel oils is located in Table 3-3. 

TABLE 3-3. Physical and Chemical Properties of Fuel Oils°... 

As a general rule, low-molecular-weight aromatic compounds help to improve the low-temperature flow properties of fuels and oils. 

Corrosion-inhibiting properties of fuel stabilizers can be a secondary effect of the dispersing action of a fuel stabilizer. By functioning as a dispersant, sludge and water are held in suspension and prevented from initiating metal surface corrosion. Also, some stabilizer dispersants can form a thin film on the metal surfaces of fuel system components. This film-forming property enables the stabilizer-dispersant to function in corrosion control. A typical oil-soluble dispersant compound is shown in FIGURE 6-3. 

C. COMMON TEST METHODS USED TO DETERMINE THE FERROUS METAL CORROSION PROPERTIES OF FUEL... 

Can adversely affect water separation properties of fuel... 

Arco Chemical. 1994. (Factual report) Topical properties of fuel oxygenates in gasoline. Potomac, Maryland Hart/IRI Fuels Information Services. 

Chemical Composition and Properties of Fuels for Jet Propulsion , Pergamon Press, NY(1962) 7) ASTM Standards for Ash from Petroleum Pro-... 

Characteristic properties of fuels with nitric acid according to Bellinger, Friedman, Bauer, Eastes and Bull [22]... 

Some of the desired properties of fuels, depending upon particular applications, include heal content, that is. Blus or calories released upon combustion per unit weight or volume of the fuel. Energy density is particularly important where a fuel is used in some form of vehicle where the fuel must he carried and thus part of the fuel is expended simply 10 transport itself. Cleanliness of burning is of major concern, not only in terms of pollutants that may be produced as the result of combustion, but... 

Table 15.1 Some physical properties of fuels with impact on combustion [3],...

Table 9.6 The composition and main properties of fuel-like products...

Table 15.2 Properties of fuel produced by pyrolysis of various plastic feedstocks. (Reproduced by permission of Masataka Tsukada)...

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