Naphthenic gas oils

Charge Stock. . Paraffinic gas oil Naphthenic gas oil 1st stage, gas oil 2nd stage, naphtha... 

Cyelopcntsne Kern River (CaUf.) Greta or Placedo (Tex.) Thermal gas oil from naph thene feeds Naphthenic gas oil and lubes... 

Naphthenic acids occur ia a wide boiling range of cmde oil fractions, with acid content increa sing with boiling point to a maximum ia the gas oil fraction (ca 325°C). Jet fuel, kerosene, and diesel fractions are the source of most commercial naphthenic acid. The acid number of the naphthenic acids decreases as heavier petroleum fractions are isolated, ranging from 255 mg KOH/g for acids recovered from kerosene and 170 from diesel, to 108 from heavy fuel oil (19). The amount of unsaturation as indicated by iodine number also increases in the high molecular weight acids recovered from heavier distillation cuts. 

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... 

Extracts (petroleum), heavy naphthenic distillate solvent Extracts (petroleum), heavy paraffinic distillate solvent Extracts (petroleum), light naphthenic distillate solvent Extracts (petroleum), light paraffinic distillate solvent Extracts (petroleum), light vacuum gas oil solvent Euel oil no. 6... 

Naphthenic-aromatic compounds are formed by the condensation of an aromatic ring with a cycloparaffin. Examples of naphthenic-aromatics include indane and tetralin and their derivatives. These compounds are common constituents of distillate fuel and light gas oil fractions. 

Bicyclic aromatics and naphthenes are important components of cracking feed stocks. The former, after cracking in the side chains to gasoline and gas, will remain as smaller bicyclic aromatics in the cracked gas oil. The latter will be converted to naphthenes and aromatics distributed in both the gasoline and gas oil, together with aliphatic gas and gasoline components. 

Crude oils are classified chemically according to the structures of tire larger molecules in the mixture. Classification methods use combinations of the words paraffinic, naphthenic, aromatic, and asphaltic. For instance, crude oil which contains a predominance of paraffinic molecules will yield very fine lubricating oils from the gas-oil fraction and paraffin wax from the residuum. Oh the other hand, if the larger molecules are aromatic and asphaltic, the heavier fractions of the crude oil are useful for pitch, roofing compounds, paving asphalts, and other such applications. 

Almost any naphthenic or parallflnic hydrocarbon heavier then methane can he steam-cracked to yield elhylene. The preferred feedstock in the United Slates has been ethane and/or propane recovered from natural gas. or from the volatile fractions of petroleum. However, because of longterm uncertainties pertaining to natural gas, many producers have been turning to heavier petroleum fractions, such as gas oils, as feedstock. The consumption of ethylene throughout the free world is estimated to be about 40 x 10 pounds per year,... 

Saturated constituents contribute less to the vacuum gas oil than the aromatics but more than the polar constituents that are now present at percentage rather than trace levels. The vacuum gas oil itself is occasionally used as heating oil but most commonly it is processed by catalytic cracking to produce naphtha or by extraction to yield lubricating oil. Within the vacuum gas oil saturates, the distribution of paraffins, /iso-paraffins and naphthenes is highly dependent upon the petroleum source. The bulk of the vacuum gas oil saturated constituents consist of /Iso-paraffins and naphthenes. The naphthenes contain from one to more than six fused rings and have alkyl substituents. For mono- and di-aromatics, the alkyl substitution typically involves one long side chain and several short methyl and ethyl substituents. 

The aromatics in vacuum gas oil may contain one to six fused aromatic rings that may bear additional naphthene rings and alkyl substituents in keeping with their boiling range. Mono- and di-aromatics account for about 50% of the aromatics in vacuum gas oil samples. 

The Illinois H-Coal syncrude contains the greatest amount of iron. This iron could be from corrosion during processing or storage, rather than from the coal itself. We have observed high iron contents in California gas oils which contain acidic and corrosive oxygen. In California gas oils, the iron is soluble in the oil as iron naphthenates (iron salts of organic acids) ... 

Catalytic Cracking Test. A standard microactivity test (MAT) was used to evaluate the conversion and selectivity of catalyst samples. The tests were done at the University of Pittsburgh s Applied Research Center (former Gulf Research Laboratory), a qualified laboratory for MAT evaluations. A standard method, developed by Gulf, was used without modification. A Cincinnati gas oil was cracked under the following conditions cat/oil=3, 16 h 1 WHSV, and 516°C. Prior to charging the reactor, all samples underwent a standard thermal pretreatment. Solids were first heat shocked for 1 h at 593°C. Next, selected materials were impregnated with 3000 ppm Ni and 6000 ppm V, as naphthenates. Then all samples were calcined for 10 h at 538°C. Finally, each material was steamed at 732°C for 14 h in a fluidized bed to produce a catalyst in a simulated equilibrium state. 

The higher ethylene yields observed in the DCC type processes has led developments towards the catalytic cracking of heavy oils to ethylene. A typical yield from cracking a gas oil (b.p. 229-340°C) with 45% paraffins, 35.7% naphthenes and aromatics 18.2% is illustrated in Table 10.5". 

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