DISTILLATION CHARACTERISTICS AND COMPOSITIONAL ANALYSIS OF ARABIAN LIGHT STRAIGHT RUN NAPHTHA

ABSTRACT

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.     

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.     

Comparison Study for the Distribution of Organo-Sulfur Containing Compounds of Two Kuwaiti Crude Oil Distillates

Abstract

This paper deals with the comparison, analysis, and characterization of two Kuwaiti crude oil samples received from different origins. (Burgan and Al-Wafra oil fields). Systematic analysis was conducted for API gravity, sulfur content, metal content, and viscosity. The representative samples of the two Kuwaiti crude oils were fractionated into naphtha (IBP–170^○C), kerosene (170–265^○C), medium gas oil (265–355^○C), and heavy gas oil (355–550^○C) using an 80 L capacity autodistillation unit “AUTODEST-800” according to ASTM D2892 and ASTM D5236. Particular attention was paid to study the distribution of various types of sulfur compounds in each of these wide cuts, which was qualitatively and quantitatively estimated by capillary gas chromatography equipped with a sulfur chemiluminescence detector, which is suitable for a wide range of sulfur systems. The fingerprinting obtained from the analysis of GC-SCD showed different families of organo-sulfur compounds in crudes, including mercaptans, sulfides, thiophenes, benzothiophenes, dibenzothiophene, benzonaphtothiophene, and their alkyl derivatives. From the analyses the behavior and distribution of the refractory and unrefractory sulfur compounds in the two Kuwaiti crude oils can now be easily followed.     

采用全二维气相色谱-飞行时间质谱表征渣油接触裂化液体产物中含硫化合物

采用全二维气相色谱-飞行时间质谱(GC×GC-TOFMS)方法对渣油接触裂化液体产物中的含硫化合物进行分子水平表征,鉴定出苯硫醚、苯硫酚、噻吩类、苯并噻吩类、二氢苯并噻吩类、二苯并噻吩类、萘噻吩类、四氢二苯并噻吩类、苯并萘噻吩类、菲噻吩类、苯并二噻吩类及噻喃类等含硫分子。通过GC×GC-TOFMS的族分离和瓦片效应重点研究了渣油接触裂化液体产物中的噻吩类、苯并噻吩类及二苯并噻吩类化合物的碳数分布,并对油品加工过程中较关注的C_2烷基取代二苯并噻吩类化合物进行了单体分子识别。结合渣油接触裂化工艺考察了接触剂活性对渣油接触裂化液体产物中的含硫化合物的分子类型分布及碳数分布的影响,结果表明,同种渣油在不同接触剂作用下接触裂化的液体产物中含硫化合物的分子类型分布基本相似,但含量分布存在明显差异。对于碳数分布,以苯并噻吩类为例,采用强微反活性的接触剂时,液体产物中的低碳数烷基(C_1~C_3)取代苯并噻吩的分布占优势,而采用弱活性接触剂时,产物中较高碳数烷基(C_4~+)取代苯并噻吩的分布占优势。     

Desulfurization of FCC Gas Oil by Solvent Extraction, Photooxidation, and Oxidizing Agents

A deep desulfurization process for FCC gas oil by a combination of liquid-liquid extraction, photochemical reaction, and treating with oxidation agents has been investigated. The process often represented by the model heterocyclic compounds, benzothiophenes (BTs) and dibenzothiophenes (DBTs). The process is comprised of three stages. Extraction of the sulfur-containing compounds from a catalytic cracked gas oil by acetonitrile, photooxidation, and photodecomposition of the sulphur compounds in the acetonitrile phase by ultraviolet irradiation from a high pressure mercury lamp, and recovery of the sulphur from the irradiated oil and treatment with oxidizing agent. The process was carried under conditions of room temperature and atmospheric pressure. Acetonitrile/water azeotropic mixture has been recycled successfully through distillation column. The sulfur in this gas oil has been decreased from 1800 ppm to 550 ppm after photo-desulfurization, and 508 ppm after treatment with the oxidizing agents. The total yield of the oil was 90-95%.     

FCC原料加氢预处理对催化柴油中硫、氮化合物分布的影响

分别采用气相色谱-脉冲火焰光度检测器（GC-PFPD）及气相色谱-氮化学发光检测器（GC-NCD）对催化裂化柴油中的硫化物和氮化物类型进行了分析,考察了加氢预处理的反应温度对FCC柴油中的硫化物、氮化物的转化规律的影响。结果表明：FCC柴油中的硫化物主要为BTs和DBTs,氮化物主要以非碱性的含氮化合物为主,吲哚类和咔唑类约占总氮含量的98%;加氢预处理后的FCC柴油中的硫化物以BTs为主,4- MDBT 和4, 6- DMDBT含量很少;随着加氢预处理温度的提高,FCC柴油氮化物中的咔唑类逐渐减少,主要以吲哚类为主。     

COMPARISON BETWEEN THE PERFORMANCE OF CONVENTIONAL AND HIGH-METAL Co-Mo AND Ni-Mo CATALYSTS IN DEEP DESULFURIZATION OF KUWAIT ATMOSPHERIC GAS OIL

ABSTRACT

Due to environmental constraints, sulfur content of diesel fuel has been restricted to very low levels (500 ppm maximum) in many countries. As a result, a greater emphasis has been placed in recent years on the development of catalysts and processes for deep desulfurization of diesel blending streams to produce low sulfur diesel fuel. In the present work we have compared the performance of a conventional Co-Mo catalyst with that of high metal loading Co-Mo and Ni-Mo catalysts in deep desulfurization of Kuwait atmospheric gas oil. The tests were carried out in a fixed bed reactor unit using 75 ml of catalyst under the conditions: P=32 bar; LHSV = 4h^?1; H₂/oil ratio = 100 ml/ml; temperature range = 330 ? 390°C. HDS activity of the high molybdenum Co-Mo catalyst was superior to that of the conventional Co-Mo hydrotreating catalyst. High metal loading Co-Mo/Al₂O₃ catalyst also showed a substantially higher HDS activity than the Ni-Mo/Al₂O₃ catalyst containing a similar high metal loading. The unreacted sulfur compounds remaining in the product after high severity hydrotreating were identified as dibenzothiophenes with alkyl substituents next to the sulfur atom. The desulfiirization of such low reactive alkyl dibenzothiophenes was found to occur at a substantially lower temperature over the high metal loading Co-Mo catalyst compared with the conventional Co-Mo catalyst. The results have been explained on the basis of the stacking and dispersion of MoS₂ slabs as well as in terms of the nature of the sulfur vacancies in the MoS₂ layers in these catalyst systems.     

塔里木原油含硫化合物的地球化学意义

塔里木盆地30余个代表性原油芳烃组分的色质和色谱－原子发射光谱分析资料表明,不同成因原油的含硫化合物含量和分布明显不同。与陆相原油相比,海相原油以高二苯并噻吩系列(>20%)、高DBT/P(>0.35)为特征,其中,塔中局限性海湾相原油以这两参数值更高而与塔北台地相原油形成区别；在二苯并噻吩系列内分布上,它们的DBT少而DMDBT丰富,反映出成油母质沉积环境性质的差别。来源于不同岩性源岩的原油中苯并噻吩系列相对于二苯并噻吩系列的含量不同,在碳酸盐岩原油中较高。      

Dearomatization of Diesel by Solvent Extraction: Influence of the Solvent Ratio and Temperature on Diesel Raffinate Properties

To comply with the stringent environmental regulations concerning the quality of fuels the production of ultra low sulfur fuels is obligatory. Consequently, the removal of aromatics from fuels has turned to be a serious issue. This is due to the fact that the presence of aromatics in fuel deters the ultra-low sulfur fuel production. Therefore the researcher’s interest has involved the dearomatization of fuels. As a result of the dearomatization, the quality of fuels improves tremendously. Here, solvent extraction was performed to dearomatize a feedstock sample with 20.1% aromatic and 166 ppm sulfur using acetonitrile. The extraction was performed at low temperature and ambient atmospheric pressure. The aromatic contents were determined via HPLC, while the ASTM methods were employed in other parameters determination. The results showed 72% minimum yield, 8.6% aromatic content, 58–64 cetane index, 73.2 ppm sulfur content, 5.4 viscosity, RI 1.4535, aniline point 82.15, specific gravity 0.824–0.812 with API 40.32–42.88 and flash point 70–78°C. The boiling range of the produced diesel fraction raffinate (172–373°C) that corresponds to C₈–C₂₄ cuts render it a potential candidate for other petrochemical applications.     

Fluid Catalytic Cracking Feed Hydrotreatment and its Impact on Distribution of Sulfur and Nitrogen Compounds in FCC Diesel

The sulfides and nitrogen compounds in FCC diesel were analyzed by gas chromatography equipped with a pulsed flame photometric detector(GC-PFPD) and gas chromatography coupled with nitrogen chemiluminescence detection(GC-NCD). And the variation of sulfides and nitrogen compounds in FCC diesel produced from gas oil feed hydrotreated at different temperatures was investigated. The test results showed that two main types of sulfur compounds, i.e. benzothiophenes(BTs) and dibenzothiophenes(DBTs) were found in diesel. Nitrogen compounds are mainly composed of non-basic nitrogen compounds, and indoles and carbazoles account for about 98% of the total nitrogen contents. The sulfides in FCC diesel obtained from hydrotreated feed are mainly BTs with a small amount of 4-MDBT and 4,6-DMDBT. With the increase in FCC feed hydrotreating temperature, indoles content in FCC diesel increases, while carbazoles content decreases.     

Influence of technological parameters and hydrogen-containing gas consumption on the efficiency of middle distillates hydrodesulphurization process

This paper presents the results of a study of the influence of process parameters (contact time, temperature and pressure) and hydrogen-containing gas consumption on the efficiency of catalytic hydrotreating of middle distillate fractions, performed using a mathematical model of the process. It was found that with the increase in the contact time of the raw material with the catalyst, the concentration of sulfides decreases more rapidly than the concentrations of benzothiophenes and dibenzothiophenes. The degree of conversion of sulfides, benzothiophenes and dibenzothiophenes increases with the process temperature in the range from 350 to 425?°C by 39.9; 37.5 and 19.4%, respectively. The greatest degree of desulfurization is achieved by simultaneous increase in pressure and temperature. Thus, at a temperature of 430?°C, an increase in pressure from 2.0 to 4.0?MPa leads to a decrease in the residual sulfur content from 230 to 13.5?ppm. With an increase in the consumption of hydrogen-containing gas from 42,000 to 50,000 m³/h, the efficiency of the hydrotreating process of the middle distillate fractions increases (the residual content of total sulfur in the hydrotreating product decreases from 55.9 to 24.8?ppm).     

CHARACTERIZATION OF KUWAITI CRUDE TBF-FRACTIONS WITH EMPHASIS ON KINEMATIC VISCOSITY - TEMPERATURE BEHAVIOR

ABSTRACT

Characterization of Kuwaiti crude oil, has been carried out in terms o API gravity, debutanized gravity, total sulfur content, Reid Vapor pressure ash content, heating value, salt content, viscosity SUS, vanadium content a: V2 O5, pour point and analysis of various metals. The true boiling poinl (TBP) fractions of this crude (IBP - 95^° C, 95 - 205^°C, 205 - 260^° C, 260 - 345^° C and 455^° C⁺;) were also characterized in terms of API gravity, total sulfui content, H₂S content, mercaptans content, molecular weight and elementa analyses for total carbon, hydrogen and nitrogen. The kinematic viscosity temperature data have been obtained for 95^°C⁺; TBP fractions for a wide range of temperatures.     

Oxidative desulfurization of catalytically cracked gasoline with hydrogen peroxide

Hydrogen peroxide desulfurization at 50°C of a catalytically cracked gasoline fraction containing methyl- and dimethylthiophenes and traces of benzothiophene and dibenzothiophene and boiling in the range of IBP-70°C in the presence of transition metal compounds Na₂MoO₄, Na₂WO₄, VOSO₄, and [Cu(NH₃)₄]CO₃ followed by adsorption on alumina has been studied. The successive oxidation of the hydrocarbon fraction in the presence of the copper and molybdenum compounds under phase transfer conditions ensures the removal of up to 96% of total sulfur.     

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.     

Origin of the unusually high dibenzothiophene concentrations in Lower Ordovician oils from the Tazhong Uplift, Tarim Basin, China

The origin of the unusually high dibenzothiophene (DBT) concentrations in Lower Ordovician oils from the Tazhong Uplift,Tarim Basin was studied by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS).The most abundant sulfur compounds in the oils are S 1 species with doublebond equivalent (DBE) values of 1-19 and 11-48 carbon atoms.The range of the number of carbon atoms in the sulfur compounds detected by the FT-ICR MS (S 1 species with DBE=9) is about ten times larger than that for sulfur compounds detected by GC/MS (DBTs).This suggests that FT-ICR MS is a much better approach than GC/MS for characterization of DBTs in crude oils.The abundance of S 1 species with DBE=1-8 decreased with increasing thermal maturity,while the abundance of S 1 species with DBE=9 (primarily DBTs) increased.Therefore,thermal maturity is an important factor in the formation of oils with high DBT concentrations.Unusually high abundances of S 1 species with low DBE values (1-8),which include sulfide,thiophene and benzothiophene,were observed in several oils,especially the TZ83 (O 1) oil with high or very high thermal maturity.Thermochemical sulfate reduction (TSR) was thought to be the reason for the high abundance of these low DBE compounds in deep reservoirs,and thermochemical sulfate reduction could affect the distribution and composition of DBTs in the oils.According to the results of FT-ICR MS analysis,there are no signs that TSR is occurring or has occurred recently for most of the Lower Ordovician oils.     

焦化柴油中二苯并噻吩类含硫化合物的加氢脱硫反应动力学

采用20 mL高压连续反应装置,在压力5.0 MPa、体积空速0.7～3.0 h^-1、氢/油体积比400、温度330℃的条件下,考察了焦化柴油中难脱除的二苯并噻吩类含硫化合物（DBTs）在工业化负载型NiMo/γ-Al₂O₃催化剂上的加氢脱硫（HDS）反应活性。采用气相色谱 脉冲火焰光度检测器（GC-PFPD）对加氢前后焦化柴油中含硫化合物进行了定量分析,研究了它们在深度HDS过程中的脱除规律,建立了难脱除DBTs的HDS反应一级动力学模型。焦化柴油的深度HDS过程中,DBTs尤其是4位和6位取代的DBTs是最难脱除的含硫化合物,各含硫化合物的HDS反应速率常数大小顺序为DBT、 4-MDBT、4-EDBT、3,6-DMDBT、4-E,6-MDBT、2,4,6-TMDBT、4,6-DMDBT。     

Gas chromatographic-mass spectrometric identification of heteroatomic compounds in a commercial blend of West Siberian oils

The amount of heteroatomic (NSO) compounds in the commercial blend of West Siberian oils that arrives at the Kirishi refinery has been determined by gas chromatography-mass spectrometry. Ten representative samples of oils differing in the total sulfur content were examined. To isolate NSO compounds from oil, the alkali extraction and solid-phase extraction procedures were used. The NSO concentration in the alkali extracts was semiquantitatively determined with the use of propanethiol as an internal standard. The alkali and solid-phase extracts obtained from the oil fractions with bp below 350°C were found to contain 48 identifiable NSO compounds. Of these, aliphatic C₆–C₈ alcohols (mainly secondary and tertiary) and ketones have been isolated. The concentrations of 28 mercaptans and phenols in the oil were estimated.     

DETERMINATION OF ORGANIC SULFUR COMPOUND TYPES IN VACUUM GAS OILS USING GC-FID-SCD METHOD

ABSTRACT

The analyses of individual organic sulfur compounds in petroleum distillates are the key to understanding the kinetics of the chemistry involved in hydrodesulfurization, HDS. A sample of vacuum gas oil (VGO) produced commercially by distillation of treated atmospheric residue was analyzed by GC-FID-SCD method for individual organic sulfur compounds characterization and quantification. Dibenzothiophene and benzonaphthothiophene and their alkyl derivatives were found to constitute almost the entire organic sulfur compound range present in the VGO. Using a relationship between the total sulfur determined by “X-ray” and “Coulomax” methods and the composition of individual sulfur compounds determined by SCD, the quantity of those organic sulfur compounds present in VGO was estimated. Despite the limit in temperature raise (325°C) in the capillary column and that the range studied (346-555°C) is higher than those limits, optimum conditions were chosen to overcome those obstacles. From the analyses the behavior of refractory and unrefractory sulfur compounds in the VGO region can now be followed easily.     

Moderate-Temperature Isomerizate — A High-Octane Component of Automotive Gasoline

The proposed theoretical solutions for revamping the unit for refining pyrocondensate into a unit for isomerization of the IBP-70°C naphtha cut provide for a significant decrease in the aromatic hydrocarbon content, which makes it necessary to add large amounts of branched C₅–C₆ paraffins to the gasolines. These compounds can be obtained by isomerization of the corresponding linear paraffins in the IBP-70°C cut. __________ Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 5, pp. 23 – 26, September – October, 2005.     

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.