Naphtha INDEX

In a single stage, without liquid recycle, the conversion can be optimized between 60 and 90%. The very paraffinic residue is used to make lubricant oil bases of high viscosity index in the range of 150 N to 350 N the residue can also be used as feedstock to steam cracking plants providing ethylene and propylene yields equal to those from paraffinic naphthas, or as additional feedstock to catalytic cracking units. 

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... 

The selection of steam cracker feedstock is mainly driven by market demand as different feedstock qualities produce different olefins yields. One of the commonly used feed quality assessment methods in practice is the Bureau of Mines Correlation Index (BMCI) (Gonzalo et al., 2004). This index is a function of average boiling point and specific gravity of a particular feedstock. The steam cracker feed quality improves with a decrease in the BMCI value. For instance, vacuum gas oil (VGO) has a high value of BMCI and, therefore, is not an attractive steam cracker feed. The commonly used feedstocks in industry are naphtha and gas oil. 

Consumers can also negotiate with feedstock suppliers on upfront payments or payment terms under which they pay a higher price than the lowest market price at the trough, but pay lower prices when product prices spike. An interesting application of this is the potential for an ethane cracker operator to convert the economics of its cracker to those of a virtual naphtha cracker, by paying an integrated gas producer-processor a price for ethane indexed to naphtha-based ethylene production costs. 

The KSF severity index is defined as a logarithmic function of the conversion A/ of a reference hydrocarbon present in the feed. Zdonik selected M-pentaoe. a compound that is always present in naphthas, and which offers the advantage that it cannot be formed in the pyrolysis of the other components by a side reaction. 

In the case gas oils, the seventy of the treatment can always be defined by the ethylene or Cs- yidd However, due to their complex composition, whidi varies widely accending to the source of tiie crude oils Grom whidi they were produced, and due to their pronounced tendency to favor the formation of coke, it is very tfiGhcuH to establish correlations designed to predict the relative ftfoduedon of the other different hydro-carbons, and consequently to define, as for tte naphthas, a value or an index that is sufficiently general smd representative. 

The distribution of compounds produced by this operation is quite different from that obtained from naphtha. The main reason for this is the pronounced aromaticity" of gas oils, which affects the maximum ethylene yield. Moreover, this parameter may substantially from one gas oil to another, and in comparable ojserating conditions this partly explains the wide differences observed in the distribution of the hydrocarbons formed. The Stone and Webster Company established a correlation between the BMCI (Bureau of Mines Correlation Index) for gas oils and the maximum ethylene yield. The BMCL created in 1940, represents an aromaticity index" deOned by the foDowing equation ... 

Over all of the products, the production cost is 7.19/GJ. This produces ethane at 373/t. However, if the natural gasoline is sold according to the prevailing crude oil price (assumed to be 70/bbl) then this will generate by-product credit of 556 million this is based on valuing the gasoline as naphtha with oil at 70/barrel. The basis of this oil price as a reference (index) price is discussed in the Appendix. This approach reduces the production costs and hence the unit ethane and LPG costs. The ethane production cost is 341/t. 

The fraction of diesel-oil-like hydrocarbons had also a triple sequence and the main aliphatic componnds may be characterized with carbon numbers 12, 15, 18, 21, 24, 27. In contrast with the experimental results of naphtha diesel oil had considerably lower concentration of aromatics. In the case of each MPW sample its concentration was not more than 1%, because aromatics with lower boiling point stayed in the naphtha-like fraction. Similarly, as mentioned above, the diesel-oil-like fraction also had favourable properties for further fuel-like application. The olefin content was a bit smaller than in case of naphtha-like fractions, because cracking reaction resulting olefins (e.g. P-scission) produced hydrocarbons with a shorter length of carbon chain. Both cetane numbers and diesel indexes of products were high enough, while the CFPP was rather low. 

Consistent with literature (12,16,27,30), we observed that the decomposition rate constant of naphthas decreases with the increasing conversion. The overall effect of inhibition is taken into account by allowing the rate constant to vary with cracking severity index, CSI. 

Analysis of the feedstocks, shown in Table 2, indicates that the density, refractive index and carbon content of the blend naphtha are higher than those of SRN. This was due to higher aromatics and naphthenes, lower alkanes and higher final boiling point. To study the effect of catalyst type on sulfitr compounds selectivity, the feedstock and products were characterized... 

Properties Colorless liquid pungent, fruity odor. D 0.783 (18/4C), bp 20.2C, mp -123.5C, vap press 740.0 mm (20C), flash p -40F (-40C) (OC), specific heat 0.650, refr index 1.3316 (20C), wt 6.50 lb/gal (20C). Miscible with water, alcohol, ether, benzene, gasoline, solvent naphtha, toluene, xylene, turpentine, and acetone. 

Properties Water-white liquid. D 1.120-1.125 (25/ 4C), refr index 1.429 (25C), flash p 230F (110C) (COC). Soluble in alcohol, acetone, and toluene insoluble in water and petroleum naphtha. Combustible. 

Properties Colorless liquid sweetish, distinctive odor. Vapor 5.3 times heavier than air, d 1.585 (25/ 4C), bp76.74C, fp-23.0C, refr index 1.4607 (20C), vap press 91.3 mm Hg (20C), wt/gal 13.22 lb (25C), flash p none. Miscible with alcohol, ether, chloroform, benzene, solvent naphtha, and most of the fixed and volatile oils insoluble in water. Noncombustible. 

Properties White, crystalline solid. Fp 70C, bp 265C, d 1.048 (20/4C), viscosity 3.47 centistokes (0C), 1.54 centistokes (120C), refr index 1.4859 (75C), flash p 275F (135C) (COC). Soluble in methanol, ethanol, isopropanol, Cellosolve (12C), naphtha, benzene, methyl ethyl ketone, and linseed oil insoluble in water and 10% sodium hydroxide. Combustible. 

Properties Colorless liquid. D 0.950 (25/4C), bp 189C, 74.5C (lOmmHg), fp-80C, viscosity 3.5 cP (25C), refr index 1.419 (25C), flash p 185F (85C) (OC). Completely miscible with water, VM P naphtha, acetone, ethanol, benzene, carbon tetrachloride, ether, methanol, monochlorobenzene, and petroleum ether. Combustible. 

Properties Colorless, volatile, mobile liquid. Hygroscopic, aromatic odor, burning and sweet taste. Bp 34.5C, fp -116.2C, d 0.7147 (20/20C), surface tension 17.0 dynes/cm (20C), refr index 1.3526 (20C), viscosity 0.00233 cP (20C), vap press 442 mm Hg (20C), specific heat 0.5476 cal/g (30C), flash p -49F (-45C), autoign temp 356F (180C), latent heat of evaporation 83.96 cal/g at bp, electric conductivity 4 X 10 3mho/cm (25C), bulk d 6 lb/gal (20C). Soluble in alcohol, chloroform, benzene, solvent naphtha, and oils slightly soluble in water. 

Properties Yellowish-brown or reddish-brown, drying oil characteristic odor. D 0.927-0.933, saponification value 191-196, iodine value 139-180, refr index 1.480. Soluble in ether, benzene, naphtha, and carbon disulfide. Combustible. 

For some liquid feedstocks such as naphthas, the componential composition is often obtained by gas chromatography (GC) and/or mass spectrometry (MS). For gas oils or heavier feedstocks, it is impossible to obtain the desired analysis. Paraffins, olefins, naphthenes, aromatics (PONA) grouping is sometimes used as a means of feed characterization. For gas oils. Bureau of Mines Correlation Index (BMCI) has been used as a parameter for feed characterization. Since the 1980s, nuclear magnetic resonance (NMR) spectroscopy has been used to characterize heavy feedstocks. 

An indication of naphtha composition may also be obtained from the determination of aniline point (ASTM D-1012, IP 2), freezing point (ASTM D-852, ASTM D-1015, ASTM D-1493) (Fig. 4.2), cloud point (ASTM D-2500) (Fig. 4.3), and solidification point (ASTM D-1493). And, although refinery treatment should ensure no alkalinity and acidity (ASTM D-847, ASTM D-1093, ASTM D-1613, ASTM D-2896, IP 1) and no olefins present, the relevant tests using bromine number (ASTM D-875, ASTM D-1159, IP 130), bromine index (ASTM D-2710), and flame ionization absorption (ASTM D-1319, IP 156) are necessary to ensure low levels (at the maximum) of hydrogen sulfide (ASTM D-853) as well as the sulfur compounds in general (ASTM D-130, ASTM D-849, ASTM D-1266, ASTM D-2324, ASTM D-3120, ASTM D-4045, ASTM D-6212, IP 107, IP 154) and especially corrosive sulfur compounds such as are determined by the Doctor test method (ASTM D-4952, IP 30). 

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... 

Naphtha feed is often characterized using PINA analysis that simply is the weight % of K-paraffin, Ao-paraffin, naphthene and aromatic compounds. If the typical commercial indexes (specific gravity, PINA analysis and TBP curves or ASTM D86) are used properly, it is possible to empirically derive detailed naphtha composition by referring to the four different hydrocarbon classes and only to a limited number of reference components within each class. In fact, the PINA information indicates the relative abundance of the four different classes directly. The specific gravity and boiling curve allow the specification of the initial and final cuts of the hydrocarbon mixture as well as the relative presence and distribution of the reference pseudo components inside each fraction. 

In addition, a method of petroleum classification has been developed that is based on other properties as well as the density of selected fractions. The method consists of a preliminary examination of the aromatic content of the fraction boiling up to 145°C as well as that of the asphaltene content, followed by more detailed examination of the chemical composition of the naphtha (b.p. <200°C). For this examination, a graph (a composite of curves expressing the relation between percentage distillate from the naphtha, the aniline point, refractive index, specific gravity, and the boiling point) is used. The aniline point after acid extraction is included in order to estimate the paraffin-naphthene ratio. 

The time series shows a. stationary pattern until a homogeneously oscillating flow rate around a constant level. However, an additive outlier occurs at time index 128. To analyse the time dependency pattern of the Naphtha time series, the effect of the outlier has to be removed. Therefore, the outlier s effect (i.e. the raise beyond the mean level) is estimated by modelling a simple linear regression model and the corresponding value of the time series is corrected by this estimate. For the corrected Naphtha time series, ACF and PACF are calculated (Figure 2.13a and Figure 2.13b). 

The ACF shows a decaying cyclic pattern whereas the PACF clearly indicates a significant partial auto-correlation at lag 1. Therefore, an AR(1) model is chosen as the initial model. To incorporate the outlier at index 128, an ARX(l) model is fitted to the original Naphtha time series where a dummy variable xt accounts for the effect of the outlieP ... 

Behind the idle time the index of the chemical scheduled at position i is provided separated by a slash. Indices of chemicals are Naphtha...1 Pygas...2 Benzene...3. 

Chem. Descrip. Mixt. of high boiling aromatics, ketones and esters Uses Surf, additive to counteract surface defects, leveling agent for solv.-based coatings, chlorinated rubber systems, silk screen inks Properties Water-wh. liq. aromatic odor sp.gr. 0.86 dens. 7.16 vapor pressure 3 mm Hg flash pt. 43 C ref. index 1.470 <1.0%. in naphtha/ 2,6 dimethyl-4-hepanone/dipentene (14/5/1)... 

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