Naphtha specifications

Table 1.6 Typical naphtha specifications and testing methods [18]...

The terminology used in oil refining is found at numerous websites, [16, 17], As an example, naphtha specifications (Table 1.6) typically involve ... 

A shell and tube cooler in an aromatics complex cools 26,200 Ib/h of naphtha (specific gravity 0.78, viscosity 0.007 cP). The cooler has 347 tubes, 16 ft long, 3/4 inch diameter. If the naphtha is on the tube side, estimate the tube side pressure drop. 

They are classified apart in this text because their use differs from that of petroleum solvents they are used as raw materials for petrochemicals, particularly as feeds to steam crackers. Naphthas are thus industrial intermediates and not consumer products. Consequently, naphthas are not subject to governmental specifications, but only to commercial specifications that are re-negotiated for each contract. Nevertheless, naphthas are in a relatively homogeneous class and represent a large enough tonnage so that the best known properties to be highlighted here. 

Two types of specifications are written into supply contracts for naphthas they concern the composition and the level of contaminants. 

Table 7.9 Specifications and test methods for naphthas. These products are industrial intermediates and are not subject to ...

We cite isomerization of Cs-Ce paraffinic cuts, aliphatic alkylation making isoparaffinic gasoline from C3-C5 olefins and isobutane, and etherification of C4-C5 olefins with the C1-C2 alcohols. This type of refinery can need more hydrogen than is available from naphtha reforming. Flexibility is greatly improved over the simple conventional refinery. Nonetheless some products are not eliminated, for example, the heavy fuel of marginal quality, and the conversion product qualities may not be adequate, even after severe treatment, to meet certain specifications such as the gasoline octane number, diesel cetane number, and allowable levels of certain components. 

Properties. The properties of the Hquid fuel oil produced by the SRC-II process are iafluenced by the particular processiag coafiguratioa. However, ia geaeral, it is an oil boiling between 177 and 487°C, having a specific gravity of 0.99—1.00, and a viscosity at 38°C of 40 SUs (123). Pipeline gas, propane and butane (LPG), and naphtha are also recovered from an SRC-II complex. 

The principal class of reactions in the FCC process converts high boiling, low octane normal paraffins to lower boiling, higher octane olefins, naphthenes (cycloparaffins), and aromatics. FCC naphtha is almost always fractionated into two or three streams. Typical properties are shown in Table 5. Properties of specific streams depend on the catalyst, design and operating conditions of the unit, and the cmde properties. 

Naphtha at one time was a more popular feed, and alkah-promoted catalysts were developed specifically for use with it. As of 1994 the price of naphtha in most Western countries is too high for a reformer feed, and natural gas represents the best economical feedstock. However, where natural gas is not available, propane, butane, or naphtha is preferentially selected over fuel oil or coal. 

A number of other words that have traditionally been used in the petroleum industry are difficult to define precisely. These refer pardy to specific hoiling ranges, but also to certain intended uses. Thus, gasoline boils lower than naphtha, and kerosenes generally higher, but these terms are applied to products that ate intended as fuels, rather than as solvents. 

Gasoline. The naphtha fraction from cmde oil distillation is ultimately used to make gasoline. The two streams are isolated early in the refining scheme so that each can be refined separately for optimum blending in order to achieve the required specifications (see Gasoline and other motor fuels). 

Creosote. In coal-tar refining, the recovery of tar chemicals leaves residual oils, including heavy naphtha, dephenolated carboHc oil, naphthalene drained oil, wash oil, strained anthracene oil, and heavy oil. These are blended to give creosotes conforming to particular specifications. 

Liquid fuels for ground-based gas turbines are best defined today by ASTM Specification D2880. Table 4 Hsts the detailed requirements for five grades which cover the volatility range from naphtha to residual fuel. The grades differ primarily in basic properties related to volatility eg, distillation, flash point, and density of No. 1 GT and No. 2 GT fuels correspond to similar properties of kerosene and diesel fuel respectively. These properties are not limited for No. 0 GT fuel, which allows naphthas and wide-cut distillates. For heavier fuels. No. 3 GT and No. 4 GT, the properties that must be limited are viscosity and trace metals. 

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... 

A variety of formulations exist for cleaning organics from burners and other fireside areas. Soot, oil, and grease removers are widely available the formulations are often very specific and can be produced in both aqueous and nonaqueous solvent bases. Nonaqueous solvents commonly include petroleum spirit, naphtha, or odorless kerosene. 

A tank containing 1500 m3 of naphtha is to be blended with two other hydrocarbon streams to meet the specifications for gasoline. The final product must have a minimum research octane number (RON) of 95, a maximum Reid Vapor Pressure (RVP) of 0.6 bar, a maximum benzene content of 2% vol and maximum total aromatics of 25% vol. The properties and costs of the three streams are given in the Table 3.5. 

The purpose of this experiment was to investigate the extent and the structural specificity of hydrogen exchange during the extraction of bituminous coal with naphthalene. Table I includes the data of an extraction experiment (E20) conducted with naphtha-lene-d8 using nitrogen as the cover gas. In the experiment, the reactants were heated at 380°C for 1 hour at 2200 psi the same apparatus was applied as in E19. After the run, the spent solvent was separated from the coal by distillation, and the coal and solvent were examined for deuterium and protium incorporation. 

Organic solvents are used to make the rubber dough. Natural rubbers are soluble in rubber solvent (a specific petroleum fraction) or naphtha. Nitrile and polychloroprene compounds require aromatic or chlorinated hydrocarbons as solvents. Often mixtures of solvents are used. 

A naphtha is desulfurized by reducing its thiophene content with hydrogen at 660 K and 30 atm.The reaction is apparently first order with k = 0.3 cc thiophene/(g catalyst)(sec). The catalyst particle diameter is 0.35 cm, true density 2.65 g/cc, specific surface 180 m2/g, porosity 40%. In an... 

The petroleum ether solvents are a specific-boiling-range naphtha, as is ligroin. Thus, the term petroleum solvent describes a special liquid hydrocarbon fraction obtained from naphtha and used in industrial processes and formulations (Weissermel and Arpe, 1978). These fractions are also referred to as industrial naphtha. Other solvents include white spirit, which is subdivided into industrial spirit [distilling between 30 and 200°C (86 to 392°F)] and white spirit [light oil with a distillation range of 135 to 200°C (275 to 392°F)]. The special value of naphtha as a solvent lies in its stability and purity. 

The data from the density (specific gravity) test method (ASTM D1298 IP 160) provides a means of identification of a grade of naphtha but is not a guarantee of composition and can only be used to indicate evaluate product composition or quality when used in conjunction with the data from other test methods. Density data are used primarily to convert naphtha volume to a weight basis, a requirement in many of the industries concerned. For the necessary temperature corrections and also for volume corrections, the appropriate sections of the petroleum measurement tables (ASTM D1250 IP 200) are used. 

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