Diesel fuel cetane index

The calculated cetane index methods were developed to help predict the fuel cetane number without extensive engine testing. Since the calculated cetane index is determined from physical property values such as the specific gravity and the 10%, 50%, and 90% distillation points, it is readily measurable from laboratory data. The ASTM methods D-976 and D-4737 are used to determine the diesel fuel cetane index. 

D. DIESEL FUEL CETANE NUMBER AND CETANE INDEX DETERMINATIONS... 

Lubricants, Fuels, and Petroleum. The adipate and azelate diesters of through alcohols, as weU as those of tridecyl alcohol, are used as synthetic lubricants, hydrauHc fluids, and brake fluids. Phosphate esters are utilized as industrial and aviation functional fluids and to a smaH extent as additives in other lubricants. A number of alcohols, particularly the Cg materials, are employed to produce zinc dialkyldithiophosphates as lubricant antiwear additives. A smaH amount is used to make viscosity index improvers for lubricating oils. 2-Ethylhexyl nitrate [24247-96-7] serves as a cetane improver for diesel fuels and hexanol is used as an additive to fuel oil or other fuels (57). Various enhanced oil recovery processes utilize formulations containing hexanol or heptanol to displace oil from underground reservoirs (58) the alcohols and derivatives are also used as defoamers in oil production. 

Diesel Fuel. Eederal diesel specifications were changed to specify a maximum of 0.05% sulfur and a minimum cetane index of 40 or a maximum aromatics content of 35 vol % for on-road diesel. Eor off-road diesel, higher sulfur is allowed. CARB specifications require 0.05% sulfur on or off road and 10% aromatics maximum or passage of a qualification test. Process technologies chosen to meet these specifications include hydrotreating, hydrocracking, and aromatics saturation. 

Other methods are also available for the estimation of diesel fuel quaUty. For example, the diesel index (DI) is defined by the relation DI = (A° F X ° API)/100, where A °F is the aniline point in degrees Fahrenheit and °API is the American Petroleum Institute gravity. A high aniline point corresponds to a high proportion of paraffins in the diesel fuel such a fuel has a high diesel index and, therefore, a high cetane number. 

It is not possible to accurately determine the cetane index for many 1 diesel and kerosene type fuel. This is because the cetane index scale cannot be utilized accurately for fuels with end points <500°F (260°C). 

The cetane index of distillate fuel can be related to the aromatic content of the blend. As fuel aromatic content increases, the cetane index will typically decrease. A general relationship exists which relates a cetane index of 40 with a diesel fuel aromatic content of about 35%. 

The catalytic Diesel fuel has a lower cetane number than the corresponding component of the virgin charge because of the changes in chemical composition effected in the cracking operation. However, in mild cracking conditions, the drop may amount to only a few numbers in Diesel index. 

The sulfur percentages of 0.02 weight-percent or less in the shale oil diesel fuels would permit these fuels to be classed as low-sulfur diesel fuels. Nitrogen percentages were low, ranging from 141 to 202 parts per million (ppm). Cetane indexes, calculated by ASTM method D-976 (7j, were excellent, ranging from 48 to 56. 

The properties of the fuel oil blend met the requirements for ASTM No. 4 fuel oil (usually considered a distillate fuel) except that its viscosity was low, falling between the specified requirements for No. 2 and No. 4 fuel oils (7 ), and its pour point of 30° F was higher than the ASTM-recommended maximum of 20° F. The fuel could be used as a low-sulfur, high-cetane-index grade 4-D diesel fuel in warm weather or where preheating facilities were available. 

Diesel index an approximation of the cetane number (q.v.) of diesel fuel (q.v.) calculated from the density. v.) and aniline point (< .v.). 

The catalytic cracking of polypropylene waste in a flnidized-bed reactor was reported by Ji [12]. It gave a yield of liquid product of 50%, the research octane number of the gasoline prodnced from plastic waste was 86, and the cetane index of the diesel fuel produced from the plastic waste was 43. 

Results show that rosin acid produces fuels with low cetane indexes, between 28 and 42 for catalyst A and between 34 and 43 for catalyst B. According to ASTM D975 (Standard Specifications for Diesel Fuel Oils), diesel fuels must have a minimum cetane number of 40 (diesel no. 2). Therefore, some of our products seem to fall into specification for diesel fuels. However, it must be taken into account that cetane index is just an estimation of cetane number, and this estimation may be inaccurate. According to ASTM D4737 standard method, this equation possesses some limitations ... 

A study about different diesel fuels for example, showed that cetane index underestimates cetane number when it is lower than 43, sometimes more than 5 units (C.N.=40, C.I. = 35.1). Therefore, the actual cetane numbers for our products can be higher than the measured ones. In the future, producing higher amounts of product to measure actual cetane numbers appears to be necessary to confirm their suitability as diesel fuel. 

The Calculated Cetane Index (CCI), though not an accurate predictor of Cetane Number for biodiesel, since it is based on a calculation using specific gravity and the distillation curve, was used to estimate the Cetane Number of the biodiesel and two diesel fuels. From the results it can be seen that biodiesel has a CCI value higher (55) than that of diesel No.2 (49). This accords the biodiesel with better cold-start properties, minimizes the formation of white smoke (emissions), and leads to less engine noise and hence improved engine durability and reduced fuel consumption. ... 

Cetane number is one of the most widely known quality characteristics of diesel fuel. It is important to not confuse cetane number with cetane index. 

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