Volatility residual fuel

Thermal Cracking. In addition to the gases obtained by distillation of cmde petroleum, further highly volatile products result from the subsequent processing of naphtha and middle distillate to produce gasoline, as well as from hydrodesulfurization processes involving treatment of naphthas, distillates, and residual fuels (5,61), and from the coking or similar thermal treatment of vacuum gas oils and residual fuel oils (5). 

Liquid fuels for ground-based gas turbines are best defined today by ASTM Specification D2880. Table 4 Hsts the detailed requirements for five grades which cover the volatility range from naphtha to residual fuel. The grades differ primarily in basic properties related to volatility eg, distillation, flash point, and density of No. 1 GT and No. 2 GT fuels correspond to similar properties of kerosene and diesel fuel respectively. These properties are not limited for No. 0 GT fuel, which allows naphthas and wide-cut distillates. For heavier fuels. No. 3 GT and No. 4 GT, the properties that must be limited are viscosity and trace metals. 

Finally, the weight of a fuel, light or heavy, refers to volatility. The most volatile fuels vaporize easily and eome out early in the distillation proeess. Heavy distillates will eome out later in the proeess. What remains after distillation is referred to as residual. The ash eontent of residual fuels is high. 

Testing residual fuel oil does not suffer from the issues that are associated with sample volatility but the test methods are often sensitive to the presence of gas bubbles in the fuel oil. An air release test is available for application to lubricating oil (ASTM D3427 IP 313) and may be applied, with modification, to residual fuel oil. However, with dark-colored samples, it may be difficult to determine... 

In an analysis of airborne coal fly ash, Natusch and co-workers (50) found that 12 elements, i.e., Pb, Tl, Sb, Cd, Se, Zn, As, Ni, Cr, S, Be, and Mn, were concentrated in the smallest diameter particles. Mercury, although not studied, was expected to follow suit because of its high volatility and probable deposition on small particles. Toca and Berry reported similar findings for lead and cadmium (5). Atmospheric vanadium (59, 60) as well as selenium, antimony, and zinc (61) arising principally from residual fuel combustion also showed a similar pattern. The health risk of this concentration phenomenon is enhanced because of the magnitude of fine particulate emissions and the ease with which these particles bypass particle collection devices, resist fallout, and readily disseminate (50). 

Coke.—The solid non-volatile residue or coke is used as fuel, especially in the iron and steel industry. Most of the coke so used is made in coke ovens in which the gas and liquid products were originally allowed to escape into the air and were wasted. In recent years much of the coal tar formerly wasted is now recovered. Thus with the development of our knowledge of the benzene series of compounds, which include valuable dyes, explosives, medicines, etc., this substance that was formerly thrown away has become a most important industrial product. So important are the compounds obtained, either directly or indirectly, from it that the name coal tar has become an adjective of common use and significance as shown by the terms, coal tar industry y coal tar productsy coal tar dyes. 

The nature of the process by which residual fuel oil is produced virtually dictates that all the metals in the original crude oil can occur in the residuum (Speight, 2001) and, thus, in the residual fuel. Metallic constituents that may actually volatilize under the distillation conditions and appear in the higher-boiling distillates are the exceptions and can appear in distillate fuel oil. 

Approximately 38% of the residual fuel oil produced annually is burned in power plants.The remainder is used for a variety of other industrial and private uses. In industrial facilities a substantial fraction of the metals found in residual fuel oil is collected in the bottom ash and in fly ash produced during its combustion. Some of the more volatile metals and metal oxides are lost to the environment as vapors together with some of the very fine particulates, which are difficult to collect. Again, however, no data presently available describe the ultimate fate of metals in residual fuel oils. 

Several analytical methods are available for the routine determination of trace elements in crude oil, some of which allow direct aspiration of the samples (diluted in a solvent) instead of the time-consuming sample preparation procedures such as wet ashing (acid decomposition) or flame or dry ashing (removal of volatile/combustible constituents). Among the techniques used for trace element determinations are flameless and flame atomic absorption (AA) spectrophotometry (ASTM Test Method D5863, Determination of Nickel, Vanadium, Iron, and Sodium in Crude Oils and Residual Fuels by Flame Atomic Absorption Spectrometry) and inductively-coupled argon plasma spectrophotometry [ASTM Test Method D5708, Determination of Nickel, Vanadium, and Iron in Crude Oils and Residual Fuels by Inductively-Coupled Plasma (ICP) Atomic Emission Spectrometry]. ICP has an... 

For most samples a volatile petroleum spirit or naphtha is suitable. For residual fuels, a prewash with an aromatic solvent such as toluene or xylene may be necessary to remove asphaltenic material. 

Vaporized fuel oil gas behaves very elosely to natural gas beeause it provides high performanee with a minimum reduetion of eomponent life. About 40% of the turbine power installed operates on liquid fuels. Liquid fuels ean vary from light volatile naphtha through kerosene to the heavy viseous residuals. The elasses of liquid fuels and their requirements are shown in Table 12-1. 

The carbon residue is a measure of the carbon compounds left in a fuel after the volatile components have vaporized. Two different carbon residue tests are used, one for light distillates, and one for heavier fuels. For the light fuels, 90% of the fuel is vaporized, and the carbon residue is found in the remaining 10%. For heavier fuels, since the carbon residue is large, 100% of the sample can be used. These tests give a rough approximation of the tendency to form carbon deposits in the combustion system. The metallic compounds present in the ash are related to the corrosion properties of the fuel. 

The majority of today s turbines arc fueled wth natural gas or No. 2 distillate oil. Recently there has been increased interest in the burning of nonstandard liquid fuel oils or applications where fuel treatment is desirable. Gas turbines have been engineered to accommodate a wide spectrum of fuels. Over the years, units have been equipped to burn liquid fuels, including naphtha various grades of distillate, crude oils, and residual oils and blended, coal-derived liquids. Many of these nonstandard fuels require special provisions. For example, light fuels like naphtha require modifications Co the fuel handling system to address high volatility and poor lubricity properties. 

Fixed carbon is the combustible residue left after the volatile matter is driven off. It is not all carbon. Its form and hardness are an indication of fuel coking properties and, therefore, serve as a guide in the selection of combustion equipment. Generally, fixed carbon represents that portion of fuel that must be burned in the solid state. 

Diesel-like products (jet fuel, diesel. No. 2 fuel oil, kerosene) are moderately volatile products that can evaporate with no residue. They have a low-to-moderate viscosity, spread rapidly into thin slicks, and form stable emulsions. They have a moderate-to-high (usually, high) toxicity to biota, and the specific toxicity is often related to type and concentration of aromatic compounds. They have the ability to penetrate substrate, but fresh (unoxidized) spills are nonadhesive. 

Coal Char Coal char is, generically, the nonagglomerated, non-fusible residue from the thermal treatment of coal however, it is more specifically the solid residue from low- or medium-temperature carbonization processes. Char is used as a fuel or a carbon source. Chars have compositions intermediate between those of coal and coke the volatile matter, sulfur content, and heating values of the chars are lower, and the ash content is higher, than those of the original coal. 

Charcoal is another organic fuel, and has been employed in high-energy mixtures for over a thousand years. It is prepared by heating wood in an air-free environment volatile products are driven off and a residue that is primarily carbon remains. Shimizu reports that a highly-carbonized sample of charcoal showed a 91 3 5 ratio of C, 11, and O atoms [2]. 

The vendor claims that the TDR process can be used to treat soil and sludge contaminated with polychlorinated biphenyls, polynuclear aromatic compounds, solvents, dioxins, furans, organic pesticides and herbicides, solvents, petroleum wastes, as well as nonhalogenated volatile and semivolatile compounds. The treated residuals from the process include recovered water, oil that can be used for recycling as an alternative fuel or for recycling or can be disposed, and clean soil that can be used as backfill. The volume of treated sludge is reduced by as much as 95% by this thermal process, depending on the initial level of contaminants. 

Fuel asphaltenes, resins, and other heavy compounds can build up as residues on engine components after evaporation and burning away of the more volatile fuel components. These residues can accumulate as deposits which may interfere with heat transfer, lubrication, and efficient fuel combustion. 

The carbon in coal can exist in two forms, volatile carbon and base carbon. Volatile carbon is released by pyrolysis while base carbon remains as a residual char or coke. Both forms of carbon in coal have been utilized in the development of synthetic fuel. 

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