DISTILLATION CHARACTERISTICS AND COMPOSITIONAL ANALYSIS OF ARABIAN LIGHT STRAIGHT RUN NAPHTHA

Straight run naphtha is a basic constituent of refined petroteum products. It consists mainly of aliphatic hydrocarbons along with small amounts of naphthenic and aromatic hydrocarbons. It has a wide boiling range between 95°F and 410°F. Currently, its main utilization is as gasoline blend, however, naphtha is a potential feedstock for the production of various petrochemicals. Continuous catalytic reforming of naphtha can produce aromatic compounds in amounts up to 70% of the reformat. Nevertheless, the catalytic reforming process is usually associated with various limitations that may be related to the wide-ranging composition of naphtha. In this study straight run naphtha derived from Arabian Light crude oil was fractionated, and the hydrocarbon composition of its different distillation cuts was determined. The results indicate that, straight run naphtha can be split into two main fractions. A light fraction boiling between ambient temperature and 225°F, consists mainly of C₇^(-) and a medium heavy fraction boiling between 225°F and 335°F, consists mainly of C₇⁽⁺⁾. Detailed distillation characteristics, along with compositional analysis of SRN seems to be useful for diversifying its processing technologies, and upgrading currently applied processing practices to yield various high-value products and petrochemicals feed stocks.     

Process for producing high octane gasoline having lower benzene content and distillation end point with its environmental effect of engine exhaust emissions

In this research, a process is discussed for upgrading reformate and power former in Iraq’s Al-Doura refinery, by reducing the amount of benzene in the gasoline product with simultaneous reduction in the gasoline’s ASTM distillation end point. The process consists of fractionation of the reformate and power former to recover that fraction (90–180°C) of hydrocarbons. This was directly used as gasoline without further conversion. The heavy bottom fraction (180°C—EBP) consisting of the aromatic and non-aromatic hydrocarbons was recovered and used as antiknock additives to gasoline. The other fraction with (IBP—90°C) was used as feedstock to producing benzene by solvent extraction. The reformate and power former fractions (90–180°C) are blended with light straight run naphtha at ratio (75: 25) to producing gasoline as well as Al Doura gasoline. It was found that the amount of benzene was reduced from 1.41 wt % in the original pool to 1.37 and 1.31 in the alternative products. Engine emissions were also reduced when using the alternative products compared with original pool product.     

An Appraisal of Hydrocarbons Conversion Reactions During Naphtha Reforming Process

Abstract

A pilot plant study was performed to understand the reforming reactions network using a blend of straight run and hydrocracked naphtha. Three major classes of reactions that occurred during reforming were naphthenes dehydrogenation, n-paraffins cracking, and dehydrocyclization. The increase in aromatics was attributed to paraffin dehydrocyclization, the selectivity of which increases with carbon number. Aromatic contents were increased, while other hydrocarbons were decreased and converted to aromatics. Naphthenes were converted to aromatics of the same carbon number. The results indicated a drop in aromatic content as the catalyst deactivated with an increase in time on stream.     

Specifics of the group and homological compositions of aromatic hydrocarbons in some Azerbaijani crude oils

The distribution character and the composition of hydrocarbons in Azerbaijani oils of different types were studied. Concentrates of aromatic hydrocarbons were isolated from the 50° fractions of crude oils and oil residues boiling above 450°C. The structural-group composition of the isolated aromatic hydrocarbons was studied by spectral methods (mass spectrometry and ¹H NMR spectroscopy).     

APPLICATION OF MULTICOLUMN VALVE SWITCHING GAS CHROMATOGRAPHY FOR THE ANALYSIS OF NAPHTHA AND KEROSENE FRACTIONS OF SAUDI ARABIAN LIGHT CRUDE OIL

Abstract

The straight run naphtha and kerosene fractions of Saudi Arabian Light crude oil were analyzed for paraffins, olefins, naphthenes and aromatics (PONA) using a gas chromatographic technique. This method is based upon group type separation according to carbon numbers using a programmed multiple valve switching sequence and employing multicolumn approach. The chromatographic operating conditions and carrier gas flow rates were selected to determine PONA contents of naphtha and kerosene fractions. These straight run fractions were produced by an automatic true boiling point (TBP) apparatus. Boiling range distributions of these fractions were determined using a standard ASTM method of simulated distillation. PONA results were compared with the literature. Total paraffins, naphthenes and aromatics agreed with each other.     

An Appraisal of Hydrocarbons Conversion Reactions During Naphtha Reforming Process

A pilot plant study was performed to understand the reforming reactions network using a blend of straight run and hydrocracked naphtha. Three major classes of reactions that occurred during reforming were naphthenes dehydrogenation, n-paraffins cracking, and dehydrocyclization. The increase in aromatics was attributed to paraffin dehydrocyclization, the selectivity of which increases with carbon number. Aromatic contents were increased, while other hydrocarbons were decreased and converted to aromatics. Naphthenes were converted to aromatics of the same carbon number. The results indicated a drop in aromatic content as the catalyst deactivated with an increase in time on stream.     

Hydrocracking of Vacuum Gas Oil: Conversion,Product Yields,and Product Quality over an Industrial Hydrocracking Catalyst System

Pilot plant experiments were conducted over an industrial hydrotreating/hydrocracking catalyst system using vacuum gas oil fraction obtained from a refinery crude distillation unit. Extensive pilot plant data were generated on the performance of industrial hydrocracking catalyst system with respect to conversion, product yields, and product quality at various operating conditions. The pilot plant experiments were carried out in a dual-reactor hydrotreating pilot plant system with downflow mode of operation. The temperature varied from 360 to 400°C and liquid hourly space velocity varied from 0.8 to 2.4 hr^?1, keeping a constant pressure of 170 kg/cm² and H₂/HC feed ratio of 845 L/L. The hydrocracked total liquid product was distilled in a true boiling point distillation unit to obtain yields and qualities of different fractions such as naphtha, kerosene, diesel, and unconverted oil. The effect of operating conditions on the performance of the hydrocracking catalyst system was discussed in detail. The kinetics of hydrocracking reaction was studied using a simple first-order reaction and a complex four-lump reaction system and the kinetic parameters were reported.     

SULFUR COMPOUND TYPE DISTRIBUTION IN NAPHTHA AND GAS OIL FRACTIONS OF KUWAITI CRUDE

ABSTRACT

The need for detailed information on the types of sulfur compounds present in various petroleum cuts has been well recognized by refiners and environmentalists worldwide. This need is growing in recent years in view of the current environmental regulations that limit the sulfur content of transportation fuels to very low levels. In the present work we have studied the distribution of different kinds of sulfur compounds present in light and middle distillates of Kuwait crude oil. A representative sample of Kuwait crude oil was fractionated into naphtha (15-160°C) and 10-15°C cuts in the gas oil boiling range (210-340°C) using an 80L capacity autodistillation unit “AUTODEST-800” according to ASTM 2892. The distribution of various types of sulfur compounds in each of these cuts was quantitatively estimated by capillary gas chromatography equipped with a sulfur chemiluminescence detector. Thiophene and its alkyl derivatives constituted about 60% of the total sulfur compounds in the naphtha fraction. The remaining 40% was composed of mercaptanes and alkyl sulfides. In the gas oil boiling range (210-340) two groups of sulfur compounds, namely, alkyl benzothiophenes and alkyl dibenzothiophenes were present. A major portion of the alkyl benzothiophenes was found in the fraction boiling in the narrow range 235-257°C. Among the alkyl dibenzothiophenes, the concentration of C, and C₂ DBTs decreased while that of higher alkyl DBTs (< C₃-DBTs) increased with increasing temperature. The C₁ and C₂ alkyl DBTs were highly concentrated in a fraction boiling between 280-325°C and these sulfur compounds were absent in the fraction boiling above 330°C. The industrial implications of these results are discussed.     

Effect of Solvents for the Production of Cyclopentane by Extractive Distillation

Abstract

In view of the rapid phasing out of fluorocarbons due to their adverse ozone-depleting potential, alternative environment-friendly chemicals are being explored for blowing polyurethane, the key insulation material in refrigeration industries. Cyclopentane with required physical and thermal conductivity properties has emerged as the most appropriate alternative as it can be acquired from light petroleum hydrocarbons, which are abundant. Light naphtha is a mixture of several closely boiling hydrocarbons and hence even a narrow fractional distillation may not enrich cyclopentane for required purity and instead it results only in an azeotropic mixture. This article describes the work carried out in obtaining commercially pure cyclopentane from light naphtha through an extraction-distillation combined operation which is commonly termed as “extractive distillation.” The solvent type and key operating parameters, namely, feed naphtha cut range (heart cut), solvent/feed ratio were studied and the results obtained were further correlated with simulated model prediction.     

神华煤液化轻质油的分离、分析及优化利用

采用常减压精馏工艺将神华煤液化轻质油切割为富含环烷烃的馏分A和富含芳烃的馏分B,并用气相色谱-质谱联用仪分析其组成。分析结果表明,环烷烃在馏分A中富集,芳烃在馏分B中富集;馏分A的芳烃潜含量(质量分数)高达75.73%,比煤液化轻质油提高了29%左右,约为直馏石脑油的2.5倍,是优质的催化重整原料;馏分B中芳烃的质量分数高达73.73%,主要为四氢萘及其C_1和C_2的烷基取代物、甲乙苯、萘、β-甲基萘,其中四氢萘及其C_1和C_2的烷基取代物较多,质量分数为38.08%,甲乙苯质量分数为13.90%,萘、β-甲基萘、茚满和C_1与C_2的烷基取代茚满的质量分数分别为3.86%,4.80%,4.31%,3.16%,具有较高的经济附加值。     

APPLICATION OF MULTICOLUMN VALVE SWITCHING GAS CHROMATOGRAPHY FOR THE ANALYSIS OF NAPHTHA AND KEROSENE FRACTIONS OF SAUDI ARABIAN LIGHT CRUDE OIL

The straight run naphtha and kerosene fractions of Saudi Arabian Light crude oil were analyzed for paraffins, olefins, naphthenes and aromatics (PONA) using a gas chromatographic technique. This method is based upon group type separation according to carbon numbers using a programmed multiple valve switching sequence and employing multicolumn approach. The chromatographic operating conditions and carrier gas flow rates were selected to determine PONA contents of naphtha and kerosene fractions. These straight run fractions were produced by an automatic true boiling point (TBP) apparatus. Boiling range distributions of these fractions were determined using a standard ASTM method of simulated distillation. PONA results were compared with the literature. Total paraffins, naphthenes and aromatics agreed with each other.     

Isolation of adamantane hydrocarbons from Cenomanian oil of the Russkoe oilfield

Adamantane hydrocarbons have been isolated from Cenomanian heavy naphthenic oil of the Russkoe field using the thiocarbamide adduction method. Steam distillation of the oil has given a fraction (boiling range 105–150°C) containing 0.36 wt % adamantane, from which a concentrate containing 18.2 wt % C₁₀–C₁₄ adamantane derivatives has been obtained. Adamantane and its derivatives in the crude oil, oil fractions, and concentrate have been identified, and adamantane has been quantified using the gas chromatography—mass spectrometry technique.     

Influence of ZnO and P2O5 Content on Modified HZSM-5 on Aromatization of FCC Gasoline

Abstract

Catalytic properties of different content of ZnO and P₂O₅ supported on HZSM-5 zeolites were studied in the conversion of FCC gasoline (75°C–120°C) into aromatic hydrocarbons with a temperature of 430°C, a liquid hourly space velocity of 1.0 hr^?1, and a pressure of 0.1 MPa. In the reaction, when the contents of ZnO and P₂O₅ are 2% and 4%, respectively, Zn-P/HZSM-5 showed the highest selectivity and activity to aromatic hydrocarbons and conversion of olefins. The content of aromatics in the liquid product and the yield of aromatics reached as high as 94.53%, 68.87%, and 51.74%, respectively.     

加氢焦化汽油作重整原料的工业试验

为寻求焦化汽油出路和缓解催化重整装置原料不足的矛盾,安庆石化总厂对焦化汽油深度加氢精制后以不同比例调入直馏油作重整原料进行工业试验。结果表明,焦化汽油加氢精制后可作重整原料,且掺炼比可达３５％。     

The Evaluation of Oil Sand Bitumen Produced From Inner Mongolia

On the basis of an analysis, the bitumen produced from Inner Mongolia oil sand belongs to a kind of sour naphthenic based oil with the properties of high density (ρ₂₀ = 0. 9996 g·cm^?3), high viscosity (υ₁₀₀ = 1553/(mm²·sec^?1)), rich resin, and asphalt. After a series of fractions is cut by true boiling distillation (TBP) SBD-β instrument and analyzed by corresponding instruments, the processing scheme of tar sand bitumen is proposed. The initial boiling point is 281°C, and the yield of diesel, lube oil, and residual oil is 4.54%, 16.73%, and 38.06%, respectively.     

HYDRODESULFURIZATION OF QAIYARAH 80-205°C NAPHTHA FRACTION OF ALUMINA SUPPORTED Co-Mo-OXIDES ( PART 2) USING STOPPED FLOW GAS CHROMATOGRAPHY

Abstract

Effective desulfurization of Qaiyarah 80-205°C, naphtha fraction resulted on alumina supported Co-Mo oxides, assembled in a GC column using H₂ as a carrier gas and the stopped-flow technique. Over 90% of 3ulfur vas removed from this partially cracked naphtha and a similar result (Ca 90%) was obtained when hydrodesulfurizing an acid-base treated naphtha.

1_H nmr studies on the chromatographically separated hydrodesulfurized fractions revealed interesting structural parameters leading to suggestions related to the occurrence of a reforming reaction and the liberation of fresh H₂ gases which further promotes hydrodesulfurization.     

Sulfur compounds in the fuel range fractions from different crude oils

A gas chromatograph coupled with sulfur chemiluminscence detector (GC-SCD) has been used for the speciation of individual sulfur compounds in fractions of different crude oils. The crude oil fractions characterized were light naphtha (C5-90°C), heavy naphtha (90–140°C), kerosene (140–240°C), and gas oil (240–370°C) fractions obtained from true boiling point distillation process. Low boiling fractions (up to 140°C) were analyzed by existing ASTM D5623 (American Society for Testing and Materials, 2009a) method for sulfur compound speciation. As there is no standard method for the distribution of sulfur compounds in high boiling samples (up to 370°C), therefore, a methodology has been developed for the diesel range samples. The identification of individual sulfur compounds were carried out by using reference sulfur compounds. The results show that type of sulfur compounds depends upon the boiling range of the fraction and source of crude oil. The major changes in the sulfur compounds profiles of different fractions are discussed. The results of this study can be used to predict the suitability of crude oil for the production of Euro-IV and V gasoline and diesel fuels.     

汽油+芳烃型重整装置原料组分的优化

在石脑油原料过剩的情况下,针对汽油+芳烃型重整装置开展了原料组分优化的研究。通过对预加氢精制油和加氢裂化石脑油各个馏分段的族组成进行分析,模拟测算各馏分段在重整反应过程中的变化,提出应将在重整反应过程中对辛烷值增加贡献最大的石脑油组分作为重整原料。装置试验结果表明,将加氢裂化石脑油120~140℃的馏分由调合汽油改为作重整原料,预加氢精制油初馏点提高至80℃,终馏点降低至169℃,可在装置加工负荷不变的情况下,每月增加效益320万元。     

AROMATIC HYDROCARBONS OBTAINED BY THERMAL CONVERSION OF GREEN RIVER OIL SHALE KEROGEN USING CO AND H2O AT ELEVATED PRESSURE

ABSTRACT

Aromatic hydrocarbons produced from the reaction of Green River oil shale with carbon monoxide and water at elevated pressure and at temperatures from 300 to 450°C were investigated. The isolation of these aromatic hydrocarbons involved ion exchange, complexation, silica gel, and alumina chromatographic techniques. Compound types present in these aromatic hydrocarbons were studied by high resolution mass spectrometry and combined gas chromatography-mass spectrometry. Compound types were mostly phenylcyclohexylal- kanes, dinaphthenobenzenes, trinaphthenobenzenes, naphthenonaphthalenes, and carotenoid types at 300°C; but at 450°C compound types were mostly alkyl-benzenes, alkylbiphenyls, and alkylnaphthalenes. The composition of aromatic hydrocarbons from the benzene-extracted bitumen of Green River oil shale was found to be similar to that in the 300°C product from the CO-H₂O reaction.     

Effect of Solvents for the Production of Cyclopentane by Extractive Distillation

In view of the rapid phasing out of fluorocarbons due to their adverse ozone-depleting potential, alternative environment-friendly chemicals are being explored for blowing polyurethane, the key insulation material in refrigeration industries. Cyclopentane with required physical and thermal conductivity properties has emerged as the most appropriate alternative as it can be acquired from light petroleum hydrocarbons, which are abundant. Light naphtha is a mixture of several closely boiling hydrocarbons and hence even a narrow fractional distillation may not enrich cyclopentane for required purity and instead it results only in an azeotropic mixture. This article describes the work carried out in obtaining commercially pure cyclopentane from light naphtha through an extraction-distillation combined operation which is commonly termed as “extractive distillation.” The solvent type and key operating parameters, namely, feed naphtha cut range (heart cut), solvent/feed ratio were studied and the results obtained were further correlated with simulated model prediction.