Paraffin, olefin, naphthene, and aromatic

When simple Hquids like naphtha are cracked, it may be possible to determine the feed components by gas chromatography combined with mass spectrometry (gc/ms) (30). However, when gas oil is cracked, complete analysis of the feed may not be possible. Therefore, some simple definitions are used to characterize the feed. When available, paraffins, olefins, naphthenes, and aromatics (PONA) content serves as a key property. When PONA is not available, the Bureau of Mines Correlation Index (BMCI) is used. Other properties like specific gravity, ASTM distillation, viscosity, refractive index. Conradson Carbon, and Bromine Number are also used to characterize the feed. In recent years even nuclear magnetic resonance spectroscopy has been... 

Hydrocarbons are segmented into a variety of categories. Each category possesses a distinct molecular profile and, in turn, set of chemical and physical properties. Each class of hydrocarbons therefore has historically served different markets. Crude petroleum is composed of four major hydrocarbon groups paraffins, olefins, naphthenes, and aromatics. 

The hydrocarbon types in the FCC feed are broadly classified as paraffins, olefins, naphthenes, and aromatics (PONA). 

In summary, the terminology used for the identification of the various methods might differ. However, in general terms, group-type analysis of petroleum is often identified by the acronyms for the names PONA (paraffins, olefins, naphthenes, and aromatics), FIONA (paraffins, isoparaffins, olefins, naphthenes, and aromatics), PNA (paraffins, naphthenes, and aromatics), PINA (paraffins. 

This is the breakdown of the percentage of paraffins, olefins, naphthenes and aromatics in gasoline. Fuel olefin content is closely monitored. High-olefin-content gasoline is unstable and can lead to various fuel problems such as deposit formation and color degradation. 

For this reason, fuels refined from paraffinic crude oils will have naturally higher cetane numbers than fuels refined from naphthenic or more aromatic crude oil. Some typical cetane number values for selected n-paraffins, olefins, naphthenes, and aromatics are shown in TABLE 5-5. 

Identifying the paraffin, olefin, naphthene, and aromatic content of fuel good for gasoline not as accurate for jet, diesel, and other mid-distillates... 

To specify charge stock characteristics, one of several options can be used specify a detailed gas chromatographic composition call the naphtha library estimate composition from general charge stock properties, such as PON A (% paraffins, olefins, naphthenes, and aromatics) and gravity or blend up to seven naphthas by utilizing the naphtha library. 

P. C. Hayes-Jr and S. D. Anderson, Paraffins, olefins, naphthenes and aromatics analysis of selected hydrocarbon distillates using on-line column switching high-performance... 

Selectivity results at constant 50% conversion are reported in Tables VI and VII for calcined and steamed zeolites, respectively. Product selectivities are divided into light gas (C1-C4), gasoline (C5-C12) and coke. The gasoline fraction is further divided into paraffin, olefin, naphthene and aromatic (PONA) components. 

Maxwell and Bonner [Ind. Eng. Chem., 49, 1187 (1957)], which is given in great detail in the API Technical Data Book—Petroleum Refining (op. cit.) and in the ASTM D 2892 test method. It includes a correction for the nature of the sample (paraffin, olefin, naphthene, and aromatic content) in terms of the UOP characterization factor, UOP-K, as given by... 

Figure 3.10 Fractions of paraffins, olefins, naphthene and aromatic products from the catalytic degradation of plastics over spent FCC catalyst in a semi-batch reactor (400°C, P/C= 10, A/= 200 rpm) (a) HDPE (b) LDPE [70]. (Reproduced with permission from Elsevier)...

The paraffins, olefins, naphthenes and aromatics (PONA) distribution of liquid product with time on stream for thermal and catalytic degradation of waste HDPE at 430°C is shown in Figure 5.11. In the case of thermal degradation, paraffin and olefin components are the main products and aromatic componnds hardly appear, without change by increase... 

Figure 5.11 Fractions of paraffin, olefin, naphthene and aromatic products for thermal (a) and catalytic (b) degradation of waste HDPE at 430°C...

A common method of classification for petroleum is the PONA system (PONA is an acronym for paraffins, olefins, naphthenes, and aromatics). Paraffins are straight-chain or branched hydrocarbons in which there are no double or triple bonds between carbon atoms. Olefins are similar to paraffins, but they contain at least one multiple bond in their chemical structure. Naphthenes are saturated hydrocarbons, just like paraffins, but they incorporate a ring of carbon atoms into their chemical structure. Aromatics contain a benzene ring in their structure. 

Paraffins, naphthenes, and aromatic hydrocarbons in gasoline and other distillates boiling up to 200°C (392 F) are determined by multidimensional gas chromatography (ASTM D-5443). Olefins that are present are converted to saturates and are included in the paraffin and naphthene distribution. However, the scope of this test does not allow it to be applicable to hydrocarbons containing oxygenates. An extended version of the method can be used to determine the amounts of paraffins, olefins, naphthenes, and aromatics (PONA) in gasoline-range hydrocarbon fractions (ASTM D-6293). 

Additionally, classes (or types) of hydrocarbons were, and still are, determined based on the capability to isolate them by separation techniques. The four fractional types into which petroleum is subdivided are paraffins, olefins, naphthenes, and aromatics (PONA). Paraffinic hydrocarbons include both normal and branched alkanes, whereas olefins refer to normal and branched alkenes that contain one or more double or triple carbon-carbon bonds. Naphthene (not to be confused with naphthalene) is a term specific to the petroleum industry that refers to the saturated cyclic hydrocarbons (cycloalkanes). Finally, the term aromatics includes all hydrocarbons containing one or more rings of the benzenoid structure. 

The fact that the relative presence of alkane and cyc/o-alkane hydrocarbons in naphtha fractions is so similar suggests that the most of the oil has undergone the same sequence of reactions or diagenesis. The difference in the naphtha volume fraction inside the oil as well as the larger difference in the aromatic components, however, may indicate the extent to which the diagenesis has proceeded. This is why it is important to define the PONA index, i.e. the relative amount of paraffins, olefins, naphthenes and aromatics, so that the relative sizes... 

The individual product components were separated from Ci to C12 by a capillary column and detected by FID. The products were divided into five groups, viz. gas oil (b.p. >221 °C), gasoline (C5-22I °C), LPG (C3-C4), dry gas (C1-C2) and coke. The gasoline fraction was further divided into paraffins, olefins, naphthenes and aromatics. The conversion was defined as the weight fraction of all products boiling below 221 °C plus coke. 

Eight cracking reactions were included in the model second-order gas oil cracking to gasoline fraction paraffins, olefins, naphthenes and aromatics and to LPG, first-order gas oil cracking to dry gas and to coke and first-order cracking of gasoline olefins to LPG. 

Compositional information from gas chromatographic analysis is more definitive than distillation data. A naphtha composition is given in Table 1. The composition is given after the naphtha has been hydrotreated to lower concentrations of olefins and contaminants. Some of the paraffin isomers are lumped together in this particular analysis. The compositional information is often categorized into the classes of paraffins, olefins, naphthenes, and aromatics, and is called a PONA. The ease of reforming feedstocks has been correlated to the sum... 

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