True Boiling Point Extended Curve of Vacuum Residue Through Molecular Distillation

Molecular distillation is a separation process that explores high vacuum, operation at reduced temperatures, and low exposition of the material at the operating temperature. The term vacuum residue (heavy petroleum fractions) refers to the bottom of the vacuum distillation, which has an atmospheric equivalent temperature (AET) above 540°C. For the assay of the properties of petroleum and petroleum products, the use of the true boiling point (TBP) distillation analysis is accepted as a common practice; however, for heavy petroleum fractions, some difficulties appear for determination of TBP of these petroleum fractions. The objective of this work is to develop a new and a more appropriated method to extend the TBP curve to use it for characterizing vacuum residue of heavy petroleum. The falling film molecular distillator was used. The results showed that it is possible to extend the TBP curve through molecular distillation process with very good precision.     

Recovery and Characterization of Petroleum Residues Through the Molecular Distillation Process

Molecular distillation process is an efficient way to separate complex residues to obtain improvement and a more complete characterization of crude oils. It presents advantages such as to generate distillation products that can be experimentally characterized, and the operation conditions of this process generate distillate cuts with an atmospheric equivalent boiling point (AEBP) above 650°C without risks of thermal degradation. The aim of this work is to carry out the separation of two vacuum residues (VR) within the process temperature range from 550 to 670°C, using the Brazilian Molecular Distillation equipment. As a result, five distillate cuts and five residues from molecular distillation processing were generated. The molecular distillation (MD) technique provided a gain in distillate yield of about 10% over the conventional methods. The efficiency of the technique was verified through the vapor pressure osmometry experiments and the extension of true boiling point (TBP) curves of petroleum. The extended TBP curves by the molecular distillation process demonstrated that this alternative method is appropriate to extend the TBP curves to temperatures above those of the conventional methods.     

Kinetic Studies on Cocracking of Petroleum Vacuum Residue with Thermoplastics and Biomass (Petrocrop)

Cracking of petroleum vacuum residue (XVR) and its cocracking with plastics (PP or PS), Calotropis procera (CL) as a binary, ternary, and quaternary mixture of these individual plastics, and CL with XVR was carried out in a Perkin-Elmer thermogravimetric analyzer (TGA) for the purpose of comparing the process of the mixture with those of the individual components. Experiments were conducted at a heating rate of 40 K/min, in the temperature range of 30-900°C. Based on the results obtained, three temperature regimes were selected for studying the nonisothermal kinetics of TGA of individual XVR, plastics, and biomass as well as of the cocracking of these with XVR, i.e., below 400°C, between 400-500°C, and above 500°C. The kinetic studies were performed using the Coats and Redfern kinetic modeling equation. The overall activation energies obtained were 25 kJ/mole for petroleum vacuum residue, 99 kJ/mole for polypropylene, 21 kJ/mole for coal, and 35 kJ/mole for the mixture of all these materials. Thus, it has been found that there exists an overall synergy when three materials were coprocessed together. The overall orders and activation energies change during coprocessing of two or three different macromolecules, including mixed vacuum residue as presently observed. The detailed results that were obtained will be reported.     

延迟焦化原料的高温模拟蒸馏和热重-质谱分析研究

延迟焦化原料一般为减压渣油,延迟焦化工艺的操作参数应随渣油性质而变,研究渣油的馏程和热解反应规律是优化渣油焦化工艺的基础。采用色谱高温模拟蒸馏研究了中海油惠州炼化分公司(惠州炼化)减压渣油的馏程和碳分布,采用热重-质谱(TG-MS)联用仪研究了渣油的热裂解行为以及热解气相产物的在线逸出特性。结果表明：惠州炼化减压渣油的初馏点为319 ℃,终馏点为733 ℃,碳数分布为C18～C120;TG-MS系统在获得热失重信息的同时,可以监测气相挥发分的逸出行为;渣油的热解主要分为3个阶段,最大失重率温度为455 ℃,固体残余量为14%,逸出产物主要为H2,CH4,C2H4,C3H6,C3H4,CO2,H2O,H2S,SO2和轻质烃。     

常减压装置极低负荷下的减压渣油循环技改及优化运行

某石化公司通过增大急冷减压渣油循环量和增加减压渣油循环的工艺技改及其优化实践,实现了300万t/a常减压蒸馏装置在加工负荷降低至设计额50%以下的连续生产。结果表明:在减压渣油循环技改及优化实施之后,该装置不仅实现了在50%低加工负荷下的安稳连续生产,而且当减压渣油循环比为35.05%时,其在减压塔的停留时间为12.55 min,满足了不大于原工艺设计的最大停留时间极限（12.8 min）许可要求;当减压渣油循环比从0提高到31.50%~50.00%时,减压渣油的收率下降了0.43~1.07个百分点,其减压渣油的500 ℃馏分体积分数下降了1.00~1.25个百分点,减三线油及减四线油的运动黏度（100 ℃）增幅分别为2.52%,3.76%,从而提高了该装置在极低加工负荷下的原料利用率。     

AN EVALUATION OF ASPHALT RIDGE (UTHA) TAR SAND BITUMEN AS A FEEDSTOCK FOR THE PRODUCTION OF ASPHALT AND TURBINE FUELS

The purpose of this study was two-fold. The first was to produce vacuum distillation residues and determine if their properties met ASTM asphalt specifications. The second was to determine if the distillates could serve as potential feedstocks for the production of aviation turbine fuels. The bitumen used for this study was the oil produced during an in situ steamflood project at the Northwest Asphalt Ridge (Utah) tar sand deposit.

Two distillation residues were produced, one at +316 °C (+600°C)and one at +399°C (+750°F). However, only the lower boiling residue met ASTM specifications, in this case, as an AC-30 asphalt. The original oil sample met specifications as an AC-5 asphalt. These residue samples exhibited some unique properties with respect to aging. It is suggested that the low aging indexes and high flow properties of the samples may be beneficial for pavements that require good low-temperature performance.

Two distillate samples were produced, one at IBP-316°C (IBP-600°F) and one at IBP-399°C (IBP-750°F). The chemical and physical properties of these samples were determined, and it was concluded that both samples appear to be potential feedstocks for the production of conventional and high-density aviation turbine fuels.     

常减压蒸馏装置减压深拔技术改造及工艺优化

针对中国石油化工股份有限公司广州分公司加工能力为8Mt／a的Ⅲ套常减压蒸馏装置存在的常压塔操作压力高、减压塔塔底渣油泵容易抽空等影响常、减压深拔的现状,采取了降低常压塔塔顶系统压力降、增加减压急冷油系统等措施。结果表明：减压渣油500℃馏出率从改造前的3．20％降低至2．67％,常压塔塔底油350℃馏出率从改造前的9．0％降低至4．3％,高价值蜡油收率提高了2．95个百分点。     

CHARACTERIZATION OF SLUDGE WAXES FROM CRUDE OIL STORAGE TANKS HANDLING OFFSHORE CRUDE

The 300°C+ and 500°C+ vacuum residues of the sludge obtained from offshore crude oil storage tanks located at our onshore facilities have been subjected to dewaxing using MBK solvent. The yield of the refined waxes were 45.38% and 43.13% (sludge basis) and melting points 92-93°C and 95-96°C respectively The waxes were mainly n-parafTins. Their simulated boiling point distribution analysis reveals a distinct himodal distribution of n-paraffins, the even carbon number homologucs between C₅₀, to C₆₀ being present at preferentially higher ratio(l.4:1) than the odd ones. The present finding are expected to improve the understanding of waxes present in offshore crude. It is also expected to help in devising process to refine waxes of lank bottom sludge.     

EVALUATION OF FEEDSTOCKS FOR DEVELOPMENT OF HYDROCRACKING CATALYSTS FOR HEAVY OIL

A number of feedstocks namely Arab Light atmospheric residue (ALAR), Arab Heavy atmospheric residue (AHAR), vacuum gas oil (VGO) and hydrotreated vacuum gas oil (HT-VGO), were evaluated for their physical and chemical characteristics. The characterization results of the feedstocks show the complex nature and composition of both residues and gas oils. The distillation results showed that about 50 weight percent of Arab Light crude consists of atmospheric residue. The elemental analysis of the ALAR showed that high amount of carbon, sulfur and nitrogen is present along with heavy metals such as nickel and vanadium. In case of Arab Heavy crude oil, the atmospheric residue is even higher, that is 57 percent and contains higher amount of metals along with more carbon, sulfur and nitrogen contents. The determination of hydrocarbon types by HPLC exhibited that ALAR contains higher amount of saturates compared to AHAR but less amount of aromatics, polars and asphaltenes. ALAR was found to have 55% saturates, 27% aromatics, 12% polars and 6% asphaltenes while AHAR has 30% saturates, 42% aromatics, 18% polars and 10% asphaltenes. Molecular weight determination indicated that the molecular weight of ALAR was determined to be 511 compared to 595 for AHAR. ALAR being lighter, showed 54% distillation at 547°C while AHAR exhibited 45% distillation at 543°C. VGO was found to have 13% saturates, 68% aromatics and 19% polars while HT-VGO had 29% saturates, 63% aromatics and 8% polars. VGO was found to have high IBP and FBP compared to HT-VGO. On the basis of the characterization data, VGO was selected to be use with catalysts containing high pore size supports such as alumina, silica alumina and clay while HT-VGO was selected as feedstock for performance evaluation of zeolite based catalysts. ALAR and AHAR will be utilized in the later stages of the catalysts development work.     

降低常减压装置重蜡油残炭的可行性探讨

针对常减压装置重蜡油(减四线)残炭、Ni,V等含量居高不下、难以作催化原料的问题,确认常压塔塔内雾沫夹带严重,使柴油拔出能力降低、操作稳定性变差,是造成减压拔出率降低的主要原因;优化常压塔拔出率、实现减压深拔是解决问题的关键。根据模拟计算,可将常压重油中低于350℃馏分油质量分数操作值由目前的12.5%降低到6%,减一线馏分的柴油量可比原操作值降低90%。调整常压拔出率,使减压塔分离效果大幅改善,雾沫夹带和减顶缩径段压力降降低,减四线残炭及金属含量可大幅度减少。     

石蜡基减压渣油生产润滑油基础油的研究

针对石蜡基减压渣油蜡含量高的特点,将其经溶剂脱沥青得到脱沥青油,再通过加氢处理-异构脱蜡-补充精制工艺得到加氢生成油,并将加氢生成油经减压蒸馏切割后得到高附加值润滑油基础油系列产品。研究结果表明：通过控制三段高压加氢深度及调整蒸馏切割温度,可生产出90BS,HVIH14,HVIH8,HVIH4,HVIH2 共5个牌号的润滑油基础油产品,以脱沥青油进料为基准时润滑油基础油总收率可达75%左右,以减压渣油为基准时润滑油基础油总收率约为34%,可实现减压渣油的差异化利用。     

原油减压深拔新工艺研究

为了最大限度地提高原油蒸馏过程中轻油的收率,提出了一种新的原油减压蒸馏工艺方法。从装置能耗、轻油收率和设备投资等方面阐述了新工艺的技术特点;利用流程模拟软件Hysys,在相同的操作条件下,用相同处理量的同种原油对新流程和常规流程进行了原油减压蒸馏模拟计算,从装置能耗、轻油收率和设备投资方面进行了对比分析。结果表明:新工艺采用减压闪蒸塔代替减压转油线,降低减压渣油收率2%～4%,使减压蜡油切割点提高到588.7℃以上,有利于原油常减压蒸馏装置的减压深拔操作;同时降低了装置能耗。对原油常减压蒸馏装置深拔设计和扩能改造具有一定的指导意义。     

减压深拔技术集成与调控Ⅱ.减压深拔原料和工艺关联与调控

进行合理减压深拔生产满足再加工原料质量要求的合格馏分油,才能实现减压深拔效益最大化。将常减压装置和再加工装置作为大系统,针对馏分油的用途,根据原料性质和质量要求,合理确定减压深拔的切割温度;对常压塔塔底汽提、减压炉流速和出口温度、洗涤段集油箱液位、减压塔各侧线馏分分割、减压塔塔底微湿式汽提等合理确定操作条件,降低减压深拔能耗;利用催化油浆强化减压蒸馏,大系统优化实现减压深拔,实现了常减压深拔工艺方面优化和调控,最大量生产合格的馏分油,从而实现整个炼油厂效益的最大化。     

Data Reconciliation Among PIONA, GC-FIMS, and SimDis Measurements for Petroleum Fractions

PIONA (paraffin, isoparaffin, olefin, naphthene, aromatic) is a widely used characterization method for petroleum fractions boiling below 200°C, while a gas chromatography-field ionization mass spectrometry (GC-FIMS)characterization method developed at the National Centre for Upgrading Technology (NCUT) provides a reliable hydrocarbon type distribution by carbon number (#C) for middle distillates boiling between 200°C-360°C. This article proposes an integrated approach to combine the results from both PIONA and GC-FIMS measurements, resulting in detailed hydrocarbon-type distribution between the initial and end boiling points of the middle distillate. Furthermore, summing up the mass in each boiling point (BP)interval (e.g., 10°C) generates an equivalent simulated distillation (SimDis) curve that needs to be reconciled with the SimDis measured by the ASTM D2887 method. This article also discusses a simple data reconciliation approach that allowed us to use the three separate pieces of information (PIONA, GC-FIMS, and SimDis) as an internally consistent basis for the derivation of molecular representation of materials characterized in such a way.     

STUDIES ON SLUDGE FROM STORAGE TANK OF WAXY CRUDE OIL PART - I : STRUCTURE AND COMPOSITION OF DISTILLATE FRACTIONS

Tank bottom sludge from storage tanks of Bombay High crude oil deposited during ten years have been studied. The yield of the sludge is approximately 0.1% wt. of the crude oil through-put. The residue boiling above 500°C amounts to over 50%. The distillate fractions collected at 50°C intervals have been analysed extensively and compared to fractions from whole crude of same boiling range. The sludge distillate are distinctly more paraffinic in nature.     

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

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.     

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.     

委内瑞拉常压渣油悬浮床加氢裂化尾油循环反应实验研究

以委内瑞拉常压渣油为原料,分别采用3种加氢裂化反应产物（＞500℃馏分、＞400℃馏分、＞350℃馏分）作为循环尾油,在高压釜中进行了425℃、14 MPa下的悬浮床加氢裂化尾油循环反应研究,考察了循环尾油馏程以及尾油外甩比对循环反应体系生焦量、沥青质含量和液体产物分布的影响,并采用SEM、1H NMR测定了焦炭形貌 和沥青质结构参数,以探索重油悬浮床加氢裂化尾油循环工艺的可行性。结果表明,相对于一次通过反应,尾油循环反应能有效提高原料转化率;采用＞500℃馏分作为循环尾油时,体系生焦量随循环反应次数的增加而持续增加,而采用＞400℃馏分或＞350℃馏分作为循环尾油时,循环反应4次后,体系生焦量、焦炭形貌、液体产物分布、沥青质含量和结构均基本保持不变。说明当选择合适馏分作为悬浮床加氢裂化循环尾油时,重油悬浮床加氢裂化尾油循环工艺可行。此外,当反应温度和压力一定时,降低循环尾油的初馏点或减小外甩尾油比可提高原料的转化率,同时会使新鲜原料空速降低。因此,为保证较高的新鲜原料空速和转化率,必须采用合适的循环尾油馏程和尾油外甩比。     

Catalytic distillation of an atmospheric petroleum resid using HZSM-5 and HY zeolites

This work presents a study of the reactive distillation of atmospheric petroleum residue (ATR) containing 10% in mass of HY or HZSM-5 zeolites. The process aims the upgrade of ATR in order to obtain valuable products. The fundamental characteristic of the process is the immediate separation under thermal conditions and subsequent reaction of the products generated by the zeolite catalysts, favoring the displacement of the equilibrium towards the desired reactions. Such reactions occurred in the heterogeneous form, adding the HY or HZSM-5 zeolites to the ATR charge, and heating the mixtures at temperatures in the range of 50 to 500°C. The heating promotes intense heat exchange, solid-liquid reactions, obtaining the desired products. In the reactive distillation process, in presence of the acid sites of the zeolites, the short contact time of the hydrocarbons thermally cracked at low pressures favored secondary cracking reactions, increasing the selectivity to lower weigh molecular hydrocarbons, in the range of liquid gases, naphta, gasoline, jet fuel, diesel and lubricants. The obtained results proved that catalytic or reactive distillation is a promising technology for waste recovery that is surplus to the atmospheric and vacuum distillation processes for the refineries.     

A Comprehensive Evaluation of High Viscous Crude Oil from Shuguang No. 1 Zone of Liaohe Oil Field

The high viscous crude oil from Shuguang No. 1 zone of Liaohe oil field has the characteristics of high density (ρ₂₀ = 0.9977 g cm^-3), great viscosity (ν₁₀₀ = 1223.9 mm² s^-1) and high pour point (48°C), which are similar to those of the residue distillation of general crude oils. It contains no gasoline distillation and the diesel oil fraction yield is just 7.19%. It is often used as fuels after emulsification. But this oil is so vicious that it cannot be atomized uniformly and burned fully. In order to make full use of it, this kind of high viscous crude oil has been evaluated comprehensively and the properties of its various distillations are analyzed respectively. The results indicate that this crude oil contains less wax, but more resins and asphaltene, which belongs to low-sulfur naphthene-base crude oils and it is the suitable material to produce high-quality paving asphalt. Based on its characteristics, the optimum processing scheme is put forward and the high-quality paving asphalt is produced by using the distillation higher than 350°C.