Diesel composition

Methane forms azeotropes with many hydrocarbons. For example, methane and n-butane at 32°F and 2660 psig form an azeotrope with 92.9 mol% methane. Azeotropes are ideal for fuel blend applications because the composition remains essentially constant as the fuel is being used and the tank is being emptied. Little has been done to date to identify the optimal temperature and pressure conditions for the formation of azeotropes for the various hydrocarbons and for commercial gasoline and diesel compositions. 

Relations between Diesel Fuel Composition and Pollutant Emissions... 

The study of the relations between diesel fuel composition and pollution caused by the diesel engine is the focus of considerable attention, particularly in Europe where this line of thought has been rapidly developing in recent years. 

Glavincevski, B., O.L. Gulder and L. Gardner (1984), Cetane number estimation of diesel fuels from carbon type structural composition . SAE paper No. S4- 34, International fuels and lubricants meeting, Baltimore, MD. 

Montagne, X., D. Merrier and J.-C. Guibet (1987), "Fouling of automotive diesel injectors. Test procedure, influence of composition of diesel oil and additives". SAE paper No. 87-2118, International fuels and lubricants meeting, Toronto, Ontario. 

However, this conventional method presents a certain number of limitations. In the first place, the traditional end-use property itself can be difficult to determine. Consider the cetane number for example is it a good characterization of diesel fuel with respect to its behavior in commercial diesel engines In the second place, concern for protecting the environment imposes new specifications which are often specifications linked to the composition of products very low content of certain contaminants, reduced levels of certain families of compounds, or even a specific compound as already discussed. 

Methanol is more soluble in aromatic than paraffinic hydrocarbons. Thus varying gasoline compositions can affect fuel blends. At room temperature, the solubiUty of methanol in gasoline is very limited in the presence of water. Generally, cosolvents are added to methanol—gasoline blends to enhance water tolerance. Methanol is practically insoluble in diesel fuel. 

The cetane number of a fuel depends on its hydrocarbon composition. In general, normal paraffins have high cetane numbers, isoparaffins and aromatics have low cetane numbers, and olefins and cycloparaffins fall somewhere in between. Diesel fuels marketed in the United States have cetane numbers ranging between 35 and 65. Most manufacturers specify a minimum cetane number of 40—45. 

Ballard Power Systems, in conjunction with the province of British Columbia and the government of Canada, have converted a diesel bus for Vancouver, B.C. Transit (43). This 9.1-m vehicle is powered by a 105-kW fuel cell. Gaseous hydrogen, stored on board the bus in DOT-approved glass-wound composite cylinders operating at 20.7 MPa (3000 psi), provides the necessary fuel requited for the 150-km projected vehicle range. 

An important appHcation of MMCs in the automotive area is in diesel piston crowns (53). This appHcation involves incorporation of short fibers of alumina or alumina—siHca in the crown of the piston. The conventional diesel engine piston has an Al—Si casting alloy with a crown made of a nickel cast iron. The replacement of the nickel cast iron by aluminum matrix composite results in a lighter, more abrasion resistant, and cheaper product. Another appHcation in the automotive sector involves the use of carbon fiber and alumina particles in an aluminum matrix for use as cylinder liners in the Prelude model of Honda Motor Co. 

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. 

Babbitt (2%) (heavy duty bearing metal introduced by I. Babbitt in 1839). The two main compositions are 80-90% Sn, 0-5% Pb, 5% Cu and 75% Pb, 12% Sn, 13% Sb, 0-1% Cu. They have the characteristics of a hard compound embedded in a soft matrix and are used mainly in railway wagons, diesel locomotives, etc. 

The efficiency of filtration must be matched to the needs of the particular application, and, this is true both quantitatively (in relation the anticipated build-up of solids in the filters) and qualitatively (in relation to the composition of the contaminants and their size). Dirt build-up varies considerably, but it is probably at its maximum with civil engineering equipment. In this field, diesel engines in trucks will steadily accumulate something like 10 ounces of solids in the crankcase oil within a month. 

The passage of the Clean Air Act Amendment (CAAA) on November 15, 1990, started a process for regulating the composition and quality of gasoline and diesel fuels sold in the United States. The CAAA s intent was to improve the nation s air quality by reducing ozone and other air pollutants. Title II of the CAAA requires the manufacture and sale of cleaner fuels in order to reduce evaporative and combustible emission of ... 

However, under more realistic test conditions Hancock and Islam showed that in burner rig tests with contaminant flux rates greater than about 0-1 mgcm h" the corrosion rate of nickel- and cobalt-base superalloys was largely independent of alloy composition in the temperature range 7(X)-850 C. However, in burner rig tests at 6(X) C, simulating diesel engine combustion, Saunders et reported that Nimonic 80A (20% Cr) had superior resistance to Stellite 6 (Co-28%Cr) and EN 52 (Fe-8%Cr-3%Si). 

If the composite is left only partially densified, it can be used as a filter for high temperature filtering systems with high collection efficiency as required in direct coal-fired gas and steam turbines. Similar systems are considered for particulate filtering in diesel engines by a carbon foam or felt coated with silicon carbide by CVI. 

Aerosil. Aerosil as a solid additive in combination with diesel is active as a defoamer [962]. The aerosil is modified with bifunctional silicoorganic compounds. The composition is added to drilling solution in the form of a 3% to 5% suspension, in an amount of 0.02% to 0.5% by weight of aerosil per weight of drilling solution. 

M. I. Khoma. Composition of foam-extinguishing agent for drilling solutions—contains waste from production of hydrophilic and hydrophobic aerosil, modified with bifunctional silico-organic compound and diesel oil. Patent SU 1795977-A, 1993. 

Due to its particular composition, biodiesel is biodegradable and allows reduced emissions, in terms of particulates and polycyclic aromatic hydrocarbons. Instead, the results of the combustion of biodiesel are contentious in relation to so-called NOx emissions, where it has been observed that such emissions are more or less increased, with respect to conventional diesel, depending on the characteristics of the engine in which it is used ... 

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