Diesel fuel carbon residue

High-carbon-residue values for marine diesel fuel, marine gas oil, and heavy marine bunker fuel can contribute significantly to exhaust system deposit problems. Deposit formation on exhaust ports and exhaust turbines have been linked directly to high carbon residue in fuel. 

Other properties of interest are carbon residue, sediment, and acidity or neutralization number. These measure respectively the tendency of a fuel to foul combustors with soot deposits, to foul filters with dirt and rust, and to corrode metal equipment. Cetane number measures the ability of a fuel to ignite spontaneously under high temperature and pressure, and it only applies to fuel used in Diesel engines. Typical properties ol fuels in the kerosene boiling range are given in Table 1. 

Carbon residue, in diesel fuel, 22 424 Carbon selenides, 22 87 Carbon sources, for fermentation, 22 25 Carbon steels, 23 291-297 cold working, 23 295-296 heat treatment of, 23 296 hot working, 23 294-295 microstructure and grain size of, 23 293-294 properties of, 23 292—293 residual elements in, 23 296-297 wrought, 23 296... 

A high carbon value for gasoline, jet fuel or 2 fuel oil is a good indication that the fuel has been contaminated with residual fuel oil. Heavy streams such as VGO, coker gas oil, and 6 fuel oil can contaminate gasoline, jet fuel and diesel fuel. These streams tend to form carbon residue when pyrolyzed and can be identified as fuel contaminants through carbon residue testing. 

Diesel fuel containing cetane improver generates higher levels of residual carbon than untreated fuel. This is probably due to the fact that the cetane improver decomposes to catalyze fuel polymerization and gum formation during fuel pyrolysis. 

The total yield of diesel fuels was 51.6 volume-percent of the in situ crude. The properties of these fuels fell within the limits (Table V) of those of corresponding petroleum diesel fuels currently marketed in the United States (8) except for the carbon residue of the S-M shale-oil diesel fuel this residue was slightly higher than those of the petroleum diesel fuels but was probably acceptable. The value of 0.36 weight-percent for the carbon residue on the 10-percent bottoms of the S-M fuel was only a... 

Carbon residue may be present in the diesel fuel in suspended form. The carbon residue can be removed by ultracentrifuging. In the Smuda process some of the light layered clays can be carried out of the pyrolysis vessel with the hot pyrolytic gases and can be entrained in the condensed fuel. 

The carbon residue of a petroleum product serves as an indication of the propensity of the sample to form carbonaceous deposits (thermal coke) under the influence of heat. In the current context, carbon residue test results are widely quoted in diesel fuel specifications. However, distillate diesel fuels that are satisfactory in other respects do not have high Con-radson carbon residue values, and the test is chiefly used on residual fuels. 

Tests for Conradson carbon residue (ASTM D-189, IP 13) (Fig. 8.1), the Ramsbottom carbon residue (ASTM D-524, IP 14), and the microcarbon carbon residue (ASTM D-4530, IP 398) are often included in specification data for diesel fuel. The data give an indication of the amount of coke that will be formed during thermal processes as well as an indication of the amount of high-boiling constituents in petroleum. 

Alkalinity additives. Those that neutralize combustion acid residue from fuels are made primarily for diesel engines. The main compounds of this class of additives are phenols and salicylates (which are natural alkaline), and sulfonates. In the case of sulfonates, their neutralizing property can be reinforced by adding basic salts such as carbonates or hydroxides. 

The main difference between gasoline and diesel fuel, as far as ETAAS are concerned, is the sample volatility. Gasoline sample can be injected directly in the electrothermal atomizer and vaporized without formation of any residue, while diesel fuel undergoes partial pyrolysis during the thermal treatment before the atomization occurs. The pyrolysis can lead to the formation of a carbonaceous residue. The carbonaceous buildup affects the atomization of carbide forming elements such as Ni and V [3]. In this work, diesel fuel samples were diluted with a suitable solvent to reduce the formation of carbon residues. 

The carbon residue value of burner fuel serves as a rough aiqMOximation of the tendency of the fuel to form deposits in vtqwrizing pot-type and sleeve-type burners. Similarly, provided alkyl nitrates are absent (or if present, provided the test is performed on the base fuel without additive) the carbon residue of diesel fuel correlates approximately with combustion chamber deposits. 

Also in diesel fuel the presence of alkyl nitrates, such as amyl nitrate, hexyl nitrate or octyl nitrate, causes a higher carbon residue value than observed in untreated fuel, which may lead to erroneous conclusions as to the coke-forming propensity of the fuel. The presence of alkyl nitrate in the fuel may be detected by Test Method D 4046. 

Daimler-Benz has accumulated data on NECAR III emissions with a dynamometer programmed for a mix of urban and suburban driving. The results were promising since there were zero emissions for nitrogen oxide and carbon monoxide, and extremely low hydrocarbon emissions of only. 0005 per gram per mile. NECAR III did produce significant quantities of carbon dioxide similar to the emissions of a direct-injection diesel engine where the fuel is injected directly into the combustion chamber. Direct-injection produces less combustion residue and unburned fuel. 

In combustion of solids such as coal, wood, and charcoal the reaction of O2 occurs with solid carbon, sometimes leaving a solid ash residue. Fuel oil drops react with O2 in a similar process in boilers and in diesel engines. Since the exothermicity of these processes creates very large temperature differences, we will describe them in the next chapter. 

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