Fuel oils distillation range

The iQxm fuel oil is applied not only to distillate products (distillate fuel oil. Chapter 9) but also to residual material, which is distinguished from distillate type fuel oil by boiling range and, hence, is referred to as residual fuel oil (ASTM D-396). 

The properties of straight run diesel fuels depend on both nature of the crude oil and selected distillation range. Thus the paraffinic crudes give cuts of satisfactory cetane number but poorer cold characteristics the opposite will be observed with naphthenic or aromatic crudes. The increasing demand for diesel fuel could lead the refiner to increase the distillation end point, but that will result in a deterioration of the cloud point. It is generally accepted that a weight gain in yield of 0.5% could increase the cloud point by 1°C. The compromise between quantity and quality is particularly difficult to reconcile. 

Naphthenic acids occur ia a wide boiling range of cmde oil fractions, with acid content increa sing with boiling point to a maximum ia the gas oil fraction (ca 325°C). Jet fuel, kerosene, and diesel fractions are the source of most commercial naphthenic acid. The acid number of the naphthenic acids decreases as heavier petroleum fractions are isolated, ranging from 255 mg KOH/g for acids recovered from kerosene and 170 from diesel, to 108 from heavy fuel oil (19). The amount of unsaturation as indicated by iodine number also increases in the high molecular weight acids recovered from heavier distillation cuts. 

Domestic fuel oils are those used primarily in the home and include kerosene, stove oil, and furnace fuel oil. Diesel fuel oils are also distillate fuel oils, but residual oils have been successhjlly used to power marine diesel engines, and mixtures of distillates and residuals have been used on locomotive diesels. Heavy fuel oils include a variety of oils, ranging from distillates to residual oils, that must be heated to 260°C or higher before they can be used. In general, heavy fuel oil consists of residual oil blended with distillate to suit specific needs. Heavy fuel oil includes various industrial oils and, when used to fuel ships, is called bunker oil. 

Bunker-fuel specifications for merchant vessels are described by ASTM D 2069, Standard Specification for Marine Fuels. Deep draft vessels carry residual (e.g., No. 6 fuel oil) or distillate-residual blend for main propulsion, plus distillate for start-up, shutdown, maneuvering, deck engines, and diesel generators. Main-propulsion fuel is identified principally by its viscosity in centistokes at 373 K. Obsolete designations include those based on Redwood No. 1 seconds at 100°F (311 K) (e.g., "MD 1500 ) and the designations "Bunker A for No. 5 fuel oil and "Bunker B and "Bunker C for No. 6 fuel oil in the lower-and upper-viscosity ranges, respectively. 

The residuum from vacuum distillation became, and still is, the basic component of residual fuel oil. It contains the heaviest fraction of the crude, including all the ash and asphaltenes. It is extremely high in viscosity and must be diluted with light distillate flux (a low viscosity distillate or residual fraction which is blended with a high viscosity residual fraction to yield a fuel in the desired viscosity range) to reach residual fuel viscosity. The lowest value distillates, usually cracked stocks, are used as flux. In some cases the vacuum residuum is visbroken to reduce its viscosity so that it requires less distillate flux. 

Table 15.4 shows typical applications for the range of oil fuels for use with major prime movers. Medium/high-speed diesel engines generally use distillate fuel oils while medium/low-speed units generally bum residual fuels. The gas turbine, which normally operates on liquid distillate fuels, is capable of running on residual fuels, although examples of these are normally associated with crude production facilities. 

Kerosene or sometimes referred to as Fuel Oil 1 is a refined petroleum distillate. Kerosenes usually have flash points within the range of 37.8 °C to 54.4 °C (100 °F to 130 °F). Therefore unless heated, kerosene will usually not produce ignitable mixtures over its surface. In atmospheric burning smoke production normally occurs. It is commonly used as a fuel and a solvent. In some applications it is treated with sulfuric acid to reduce the content of aromatics, which bum with a smoky flame. 

Over the years, the refinery has produced a range of petroleum products including liquid petroleum gas, gasoline, chemicals, solvents, distillate fuels, gas oils, lubricating oils, greases, asphalt products, and bunker fuels. The primary products of the refinery are currendy gasoline, jet fuel, and diesel. Minor products include coke, sulfur, naphtha, and fuel oil. The refinery processes approximately 200,000 barrels... 

The term white distillate is applied to all the refinery streams with a distillation range between approximately 80 and 360°C (175 to 680°F) at atmospheric pressure and with properties similar to the corresponding straight-run distillate from atmospheric crude distillation. Light distillate products (i.e., naphtha, kerosene, jet fuel, diesel fuel, and heating oil) are all manufactured by appropriate blending of white distillate streams. 

The impact of the release of liquid products on the environment can, in part, be predicted from knowledge of the properties of the released liquid. Each part of an ocular liquid product from petroleum has its own set of unique analytical characteristics (Speight, 1999, 2002). Since these are well documented, there is no need for repetition here. The decision is to include the properties of the lowest-boiling liquid product (naphtha) and a high-boiling liquid product (fuel oil). For the properties of each product (as determined by analysis) a reasonable estimate can be made of other liquid products, but the relationship may not be linear and is subject to the type of crude oil and the distillation range of the product. 

Source Schauer et al. (1999) reported naphthalene in diesel fuel at a concentration of 600 pg/g and in a diesel-powered medium-duty truck exhaust at an emission rate of 617 pg/km. Detected in distilled water-soluble fractions of 87 octane gasoline (0.24 mg/L), 94 octane gasoline (0.21 mg/L), Gasohol (0.29 mg/L), No. 2 fuel oil (0.60 mg/L), jet fuel A (0.34 mg/L), diesel fuel (0.25 mg/L), military jet fuel JP-4 (0.18 mg/L) (Potter, 1996), and used motor oil (116 to 117 pg/L) (Chen et al, 1994). Lee et al. (1992) investigated the partitioning of aromatic hydrocarbons into water. They reported concentration ranges from 350 to 1,500 mg/L and 80 to 300 pg/L in diesel fuel and the corresponding aqueous phase (distilled water), respectively. Diesel fuel obtained from a service station in Schlieren, Switzerland contained 708 mg/L naphthalene (Schluep et al, 2001). 

Exports of fuel oil no. 1 between 1972 and 1975 ranged from 14,000 tons in 1972 to 98,000 tons in 1975 (HSDB 1991). Exports of distillate fuel oils (which include fuel oil no. 1, fuel oil no. 2, diesel fuel, and fuel oil no. 4) increased almost 100-fold between 1975 and 1990 (API 1991). In 1975, a yearly average of... 

Cycle Oil. Heavier, distillate range compounds formed during FCC processing can accumulate within the FCC fractionator. The primary fraction is called light cycle oil (LCO) and contains high percentages of monoaromatic and diaromatic compounds plus olefins and heavier branched paraffins. Unhydrotreated LCO is often quite unstable and has a very low cetane number. For this reason, it is blended into diesel fuel in controlled amounts. Heavy cycle oil and heavy naphtha are additional side cuts that can be produced. These streams can be pumped around to remove heat from the fractionator, used to supply heat to other refinery units, or used as low-quality blendstock component. 

A variety of non-hydrocarbon species is found in crude oil. These compounds are found in all molecular weight ranges of crude oil components, but seem to concentrate in the heavier distillate and residual oil fractions. The effect of these materials on processing equipment, refining catalysts, and finished product quality can be dramatic. Corrosion, catalyst poisoning, and fuel stability problems can all be due to the effect of these nonhydrocarbon species. 

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