Cetane number ( cetane rating ) ( CN ) is an indicator of the combustion speed of diesel fuel and compression needed for ignition . It plays a similar role for diesel as octane rating does for gasoline . The CN is an important factor in determining the quality of diesel fuel, but not the only one; other measurements of diesel fuel's quality include (but are not limited to) energy content, density , lubricity, cold-flow properties and sulfur content.
41-411: The cetane number of a fuel is defined by finding a blend of cetane and isocetane with the same ignition delay. Cetane has a cetane number defined to be 100, while isocetane's measured cetane number is 15, replacing the former reference fuel alpha-methylnaphthalene , which was assigned a cetane number of 0. Once the blend is known, the cetane number is calculated as a volume-weighted average, rounded to
82-413: A biofuel . Most simple ethers, including liquid ones, such as diethyl ether can be used as diesel fuels, although the lubricity can be of concern. Cetane is the hydrocarbon with chemical formulas C 16 H 34 and specifically the structural formula CH 3 (CH 2 ) 14 CH 3 . Also named n-hexadecane, it is an unbranched saturated alkane . Cetane ignites with a short delay under compression, and
123-438: A cetane number of 70+. Alkyl nitrates (principally 2-ethylhexyl nitrate) and di- tert -butyl peroxide are used as additives to raise the cetane number. Biodiesel from vegetable oil sources have been recorded as having a cetane number range of 46 to 52, and animal-fat based biodiesels cetane numbers range from 56 to 60. Dimethyl ether is a potential diesel fuel as it has a high cetane rating (55-60) and can be produced as
164-414: A common thermoplastic material. Addition reactions apply to alkenes and alkynes. It is because they add reagents that they are called unsaturated. In this reaction a variety of reagents add "across" the pi-bond(s). Chlorine, hydrogen chloride, water , and hydrogen are illustrative reagents. Polymerization is a form of addition. Alkenes and some alkynes also undergo polymerization by opening of
205-426: A double bond between carbon atoms are sometimes referred to as 'olefins'. The predominant use of hydrocarbons is as a combustible fuel source. Methane is the predominant component of natural gas. C through C alkanes, alkenes, cycloalkanes, and aromatic hydrocarbons are the main components of gasoline , naphtha , jet fuel , and specialized industrial solvent mixtures. With the progressive addition of carbon units,
246-413: A manual-wheel to increase the compression ratio (and therefore the peak pressure within the cylinder) of the engine until the time between fuel injection and ignition is 2.407 ms. The resulting cetane number is then calculated by determining which mixture of cetane ( hexadecane ) and isocetane (2,2,4,4,6,8,8-heptamethylnonane) will result in the same ignition delay. Another reliable method of measuring
287-542: A minimum cetane number of 60 with the typical value being at 63. Neste MY Renewable Diesel sold in Finland has a minimum cetane number of 70. In North America, most states adopt ASTM D975 as their diesel fuel standard and the minimum cetane number is set at 40, with typical values in the 42-45 range. Premium diesel fuel may or may not have higher cetane number depending on the supplier. Premium diesel often use additives to improve CN and lubricity , detergents to clean
328-525: A minimum of 38 in 1994 and 40 in 2000. The standard for diesel sold in European Union , Iceland , Norway and Switzerland is defined by standard EN 590 . Since 1 January 2001 EN 590 demands a minimum cetane index of 46 and a minimum cetane number of 51. Premium diesel fuel can have a cetane number as high as 60. In Finland, premium diesel fuels sold by filling station chains St1 (Diesel Plus), Shell (containing GTL) and ABC (Smart Diesel) have
369-529: A single C–C bond it is alkane metathesis , for a double C–C bond it is alkene metathesis (olefin metathesis), and for a triple C–C bond it is alkyne metathesis . The vast majority of hydrocarbons found on Earth occur in crude oil , petroleum, coal , and natural gas. Since thousands of years they have been exploited and used for a vast range of purposes. Petroleum ( lit. ' rock oil ' ) and coal are generally thought to be products of decomposition of organic matter. Coal, in contrast to petroleum,
410-468: A two neutral radical atoms ( homolytic fission ). all the way to CCl 4 ( carbon tetrachloride ) all the way to C 2 Cl 6 ( hexachloroethane ) Aromatic compounds, almost uniquely for hydrocarbons, undergo substitution reactions. The chemical process practiced on the largest scale is the reaction of benzene and ethene to give ethylbenzene : The resulting ethylbenzene is dehydrogenated to styrene and then polymerized to manufacture polystyrene ,
451-696: Is also potential to harvest hydrocarbons from plants like Euphorbia lathyris and E. tirucalli as an alternative and renewable energy source for vehicles that use diesel. Furthermore, endophytic bacteria from plants that naturally produce hydrocarbons have been used in hydrocarbon degradation in attempts to deplete hydrocarbon concentration in polluted soils. Saturated hydrocarbons are notable for their inertness. Unsaturated hydrocarbons (alkanes, alkenes and aromatic compounds) react more readily, by means of substitution, addition, polymerization. At higher temperatures they undergo dehydrogenation, oxidation and combustion. The cracking of saturated hydrocarbons
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#1732783098469492-427: Is an alkane hydrocarbon with the chemical formula C 16 H 34 . Hexadecane consists of a chain of 16 carbon atoms , with three hydrogen atoms bonded to the two end carbon atoms, and two hydrogens bonded to each of the 14 other carbon atoms. Cetane is often used as a shorthand for cetane number , a measure of the combustion of diesel fuel . Cetane ignites very easily under compression; for this reason, it
533-563: Is an organic compound consisting entirely of hydrogen and carbon . Hydrocarbons are examples of group 14 hydrides . Hydrocarbons are generally colourless and hydrophobic ; their odor is usually faint, and may be similar to that of gasoline or lighter fluid . They occur in a diverse range of molecular structures and phases: they can be gases (such as methane and propane ), liquids (such as hexane and benzene ), low melting solids (such as paraffin wax and naphthalene ) or polymers (such as polyethylene and polystyrene ). In
574-538: Is assigned a cetane number of 100, and serves as a reference for other fuel mixtures. Hexadecyl is an alkyl radical of carbon and hydrogen derived from hexadecane, with formula C 16 H 33 and with mass 225.433, occurring especially in cetyl alcohol. It confers strong hydrophobicity on molecules containing it. Carboplatin modified with hexadecyl and polyethylene glycol has increased liposolubility and PEGylation , proposed to useful in chemotherapy , specifically non-small-cell lung cancer . Hexadecyl
615-444: Is assigned a cetane number of 100. Alpha-methylnaphthalene , which has a long delay period, was assigned a cetane number of 0, but has been replaced as a reference fuel by 2,3,4,5,6,7,8-heptamethylnonane , which is assigned a cetane number of 15. All other hydrocarbons in diesel fuel are indexed to cetane as to how rapidly they ignite under compression, i.e. diesel engine conditions. Since hundreds of components comprise diesel fuel,
656-400: Is called autoxidation , begins with the formation of hydroperoxides (ROOH). Combustion of hydrocarbons is currently the main source of the world's energy for electric power generation , heating (such as home heating), and transportation. Often this energy is used directly as heat such as in home heaters, which use either petroleum or natural gas . The hydrocarbon is burnt and the heat
697-537: Is defined as the ignition delay. This measured ignition delay is then used to calculate the DCN of the fuel. The fuel's DCN is then calculated using an empirical inverse relationship to ignition delay. Because of the reproducibility, material cost, and speed of the IQT, this has been the definitive source for DCN measurements of fuels since the late 2000s. Another reliable method of measuring the derived cetane number of diesel fuel
738-482: Is estimated at more than 58 million metric tons, which will increase to 60 million tons in 2022. Hydrocarbons are also prevalent in nature. Some eusocial arthropods, such as the Brazilian stingless bee, Schwarziana quadripunctata , use unique cuticular hydrocarbon "scents" in order to determine kin from non-kin. This hydrocarbon composition varies between age, sex, nest location, and hierarchal position. There
779-463: Is richer in carbon and poorer in hydrogen. Natural gas is the product of methanogenesis . A seemingly limitless variety of compounds comprise petroleum, hence the necessity of refineries. These hydrocarbons consist of saturated hydrocarbons, aromatic hydrocarbons, or combinations of the two. Missing in petroleum are alkenes and alkynes. Their production requires refineries. Petroleum-derived hydrocarbons are mainly consumed for fuel, but they are also
820-530: Is the Fuel Ignition Tester (FIT). This instrument applies a simpler, more robust approach to CN measurement than the CFR. Fuel is injected into a constant volume combustion chamber in which the ambient temperature is approximately 575 °C. The fuel combusts, and the high rate of pressure change within the chamber defines the start of combustion. The ignition delay of the fuel can then be calculated as
861-616: Is the main industrial route to alkenes and alkyne . These reactions require heterogeneous catalysts and temperatures >500 °C. Widely practice conversions of hydrocarbons involves their reaction with oxygen. In the presence of excess oxygen, hydrocarbons combust. With, however, careful conditions, which have been optimized for many years, partial oxidation results. Useful compounds can obtained in this way: maleic acid from butane , terephthalic acid from xylenes , acetone together with phenol from cumene (isopropylbenzene), and cyclohexanone from cyclohexane]]. The process, which
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#1732783098469902-398: Is the paucity of enzymes that act on them. Nonetheless, the area has received regular attention. Bacteria in the gabbroic layer of the ocean's crust can degrade hydrocarbons; but the extreme environment makes research difficult. Other bacteria such as Lutibacterium anuloederans can also degrade hydrocarbons. Mycoremediation or breaking down of hydrocarbon by mycelium and mushrooms
943-597: Is used to heat water, which is then circulated. A similar principle is used to create electrical energy in power plants . Both saturated and unsaturated hydrocarbons undergo this process. Common properties of hydrocarbons are the facts that they produce steam, carbon dioxide and heat during combustion and that oxygen is required for combustion to take place. The simplest hydrocarbon, methane , burns as follows: In inadequate supply of air, carbon black and water vapour are formed: And finally, for any linear alkane of n carbon atoms, Partial oxidation characterizes
984-541: The Solar System . Lakes of liquid methane and ethane have been found on Titan , Saturn 's largest moon, as confirmed by the Cassini–Huygens space probe. Hydrocarbons are also abundant in nebulae forming polycyclic aromatic hydrocarbon compounds. Burning hydrocarbons as fuel, which produces carbon dioxide and water , is a major contributor to anthropogenic global warming . Hydrocarbons are introduced into
1025-454: The fossil fuel industries, hydrocarbon refers to naturally occurring petroleum , natural gas and coal , or their hydrocarbon derivatives and purified forms. Combustion of hydrocarbons is the main source of the world's energy. Petroleum is the dominant raw-material source for organic commodity chemicals such as solvents and polymers. Most anthropogenic (human-generated) emissions of greenhouse gases are either carbon dioxide released by
1066-625: The fuel injectors and minimize carbon deposits, water dispersants, and other additives depending on geographical and seasonal needs.. California diesel fuel has a minimum cetane of 53. Under the Texas Low Emission Diesel (TxLED) program there are 110 counties where diesel fuel must have a cetane number of 48 or greater, or else must use an approved alternative formulation or comply with the designated alternative limits. Neste MY Renewable Diesel sold in North America has
1107-495: The burning of fossil fuels , or methane released from the handling of natural gas or from agriculture. As defined by the International Union of Pure and Applied Chemistry 's nomenclature of organic chemistry , hydrocarbons are classified as follows: The term 'aliphatic' refers to non-aromatic hydrocarbons. Saturated aliphatic hydrocarbons are sometimes referred to as 'paraffins'. Aliphatic hydrocarbons containing
1148-490: The derived cetane number (DCN) of diesel fuel is the Ignition Quality Tester (IQT). This instrument applies a simpler, more robust approach to CN measurement than the CFR. Fuel is injected into a constant volume combustion chamber at approximately 575 °C and 310 psi (21 bar). The time between the start of injection and the recovery of the combustion chamber pressure to 310 psi (21 bar)
1189-524: The environment through their extensive use as fuels and chemicals as well as through leaks or accidental spills during exploration, production, refining, or transport of fossil fuels. Anthropogenic hydrocarbon contamination of soil is a serious global issue due to contaminant persistence and the negative impact on human health. When soil is contaminated by hydrocarbons, it can have a significant impact on its microbiological, chemical, and physical properties. This can serve to prevent, slow down or even accelerate
1230-495: The growth of vegetation depending on the exact changes that occur. Crude oil and natural gas are the two largest sources of hydrocarbon contamination of soil. Bioremediation of hydrocarbon from soil or water contaminated is a formidable challenge because of the chemical inertness that characterize hydrocarbons (hence they survived millions of years in the source rock). Nonetheless, many strategies have been devised, bioremediation being prominent. The basic problem with bioremediation
1271-509: The multiple bonds to produce polyethylene , polybutylene , and polystyrene . The alkyne acetylene polymerizes to produce polyacetylene . Oligomers (chains of a few monomers) may be produced, for example in the Shell higher olefin process , where α-olefins are extended to make longer α-olefins by adding ethylene repeatedly. Some hydrocarbons undergo metathesis , in which substituents attached by C–C bonds are exchanged between molecules. For
Cetane number - Misplaced Pages Continue
1312-402: The nearest whole number, of cetane's 100 and isocetane's 15. Cetane number is an inverse function of a fuel's ignition delay, the time period between the start of ignition and the first identifiable pressure increase during combustion of the fuel. In a particular diesel engine, higher cetane fuels will have shorter ignition delay periods than lower cetane fuels. Cetane numbers are only used for
1353-520: The number of distillation points that are used. These days most oil companies use the '4-point method', ASTM D4737, based on density and 10% 50% and 90% recovery temperatures. The '2-point method' is defined in ASTM D976 and uses just density and the 50% recovery temperature. This 2-point method tends to overestimate the cetane index and is not recommended. Cetane index calculations cannot account for cetane improver additives and therefore do not measure
1394-406: The overall cetane number of that fuel is the average cetane quality of all the components. High-cetane components have a disproportionate influence, hence the use of high-cetane additives. Cetane numbers are rather difficult to measure accurately, as it requires a special diesel engine called a Cooperative Fuel Research (CFR) engine. Under standard test conditions, the operator of the CFR engine uses
1435-401: The reactions of alkenes and oxygen. This process is the basis of rancidification and paint drying . Benzene burns with sooty flame when heated in air: Saturated hydrocarbons react with chlorine and fluorine . In the case of chlorination, one of the chlorine atoms replaces a hydrogen atom. The reactions proceed via free-radical pathways , in which the halogen first dissociates into
1476-454: The relatively light distillate diesel oils. For heavy (residual) fuel oil two other scales are used, CCAI and CII . Generally, diesel engines operate well with a CN from 48 to 50. Fuels with lower cetane number have longer ignition delays, requiring more time for the fuel combustion process to be completed. Hence, higher speed diesel engines operate more effectively with higher cetane number fuels. In Europe, diesel cetane numbers were set at
1517-737: The simple non-ring structured hydrocarbons have higher viscosities , lubricating indices, boiling points, and solidification temperatures. At the opposite extreme from methane lie the heavy tars that remain as the lowest fraction in a crude oil refining retort. They are collected and widely utilized as roofing compounds, pavement material ( bitumen ), wood preservatives (the creosote series) and as extremely high viscosity shear-resisting liquids. Some large-scale non-fuel applications of hydrocarbons begin with ethane and propane, which are obtained from petroleum and natural gas. These two gases are converted either to syngas or to ethylene and propylene respectively. Global consumption of benzene in 2021
1558-517: The source of virtually all synthetic organic compounds, including plastics and pharmaceuticals. Natural gas is consumed almost exclusively as fuel. Coal is used as a fuel and as a reducing agent in metallurgy . A small fraction of hydrocarbon found on earth, and all currently known hydrocarbon found on other planets and moons, is thought to be abiological . Hydrocarbons such as ethylene, isoprene, and monoterpenes are emitted by living vegetation. Some hydrocarbons also are widespread and abundant in
1599-466: The time elapsed between the start of fuel injection and the start of combustion. The fuel's derived cetane number can then be calculated using an empirical inverse relationship to ignition delay. Another statistic used by fuel-users to control quality is the cetane index (CI), which is a calculated number based on the density and a distillation range of the fuel. There are various versions of this, depending on whether metric or Imperial units are used, and
1640-455: The total cetane number for additized diesel fuels. Diesel engine operation is primarily related to the actual cetane number, and the cetane index is merely an estimation of the base (unadditized) cetane number. The industry standards for measuring cetane number are ASTM D613 (ISO 5165) for the CFR engine, D6890 for the IQT, and D7170 for the FIT. Cetane Hexadecane (also called cetane )
1681-401: Was used from 1982 for radiolabelling , and this continues to be useful, for example for radiolabelling exosomes and hydrogels , and for positron emission tomography . Hexadecyl platelet-activating factor has profound effects on the lung, and hexadecyl glyceryl ether participates in the biosynthesis of plasmalogens . Hydrocarbon In organic chemistry , a hydrocarbon