BaX分子筛吸附C8芳烃作用机理

采用正则系综蒙特卡洛方法模拟等量4种C₈芳烃分子分别在SiFAU和BaX分子筛上的吸附行为,并结合量子化学计算和波函数分析,基于分子筛组成和结构、C₈芳烃分子结构和电子分布特征进行吸附机理研究。蒙特卡洛模拟结果表明：4种C₈芳烃分子的密度分布主要在分子筛超笼内,吸附能分布近似为正态分布,吸附状态多样化;SiFAU上吸附位随机且范围广,但对二甲苯无选择性;BaX上吸附位集中在超笼内的Ba附近,平均吸附热由高到低的顺序为对二甲苯、乙苯、邻二甲苯、间二甲苯,与BaX分子筛对C₈芳烃吸附选择性的实验结果顺序一致。波函数分析结果表明,4种C₈芳烃分子静电势分布相似,芳环区域静电势为负,静电势极小值点偏离于取代基方向。考虑乙苯侧链柔顺性,将C₈芳烃分子的负静电势面积与其在BaX分子筛上的平均吸附能进行关联,阐明电子分布特征对吸附性能的影响。     

焦化蜡油加工利用技术研究现状

介绍了焦化蜡油加工利用技术的研究现状,包括催化裂化（FCC）吸附转化加工焦化蜡油（DNCC）工艺、焦化蜡油FCC分区反应工艺、络合脱氮-FCC组合工艺、溶剂精制-FCC组合工艺、溶剂精制-加氢裂化组合工艺等的技术路线及其特点,指出了溶剂精制副产物芳烃组分的利用途径。     

焦化蜡油预处理及综合利用的技术措施

焦化蜡油是延迟焦化工艺过程中产生的一种产品,由于其碱性氮化物、稠环芳烃、胶质含量高,使其加工利用受到限制,需要进行预处理。介绍了焦化蜡油的性质,综述了焦化蜡油预处理及综合利用的技术措施,包括加氢精制、溶剂精制、络合脱氮、氧化处理等预处理方法,经过预处理可作为催化裂化或加氢裂化原料,经溶剂抽提可回收芳烃等,对焦化蜡油的综合利用前景进行了展望。     

焦化柴油氮化物组成分布及其在加氢转化过程中的分子选择性

采用气相色谱和电喷雾高分辨质谱深入分析焦化柴油及其窄馏分中氮化物分子组成,研究不同加氢脱氮条件下反应规律,揭示氮化物分布及加氢过程分子选择性,讨论脱氮反应机理。焦化柴油氮化物以吲哚类、咔唑类中性氮化物为主,其次为苯胺类、吡啶类、喹啉类碱性氮化物。随着馏分变重,总氮和碱性氮含量增加。在选定的基准加氢反应条件下,总氮、中性氮、碱性氮和总硫的脱除率均达到99%以上。通过升温、增压、降低体积空速等优化操作,可以达到更高的加氢脱氮和脱硫率。在加氢过程中,长烷基取代氮化物转化为短烷基取代氮化物,部分中性氮加氢转化为碱性氮。加氢产物中残余的氮化物主要为C₂～C₅烷基取代咔唑类;在加氢产物中检测到环烷胺类碱性氮化物中间体,证实了柴油加氢脱氮反应路径。     

全二维气相色谱-飞行时间质谱法分析表征重馏分油中多环芳烃化合物

建立全二维气相色谱-飞行时间质谱分析方法,利用该方法对重馏分油中多环芳烃进行详细表征,通过标准化合物的保留时间、质谱图和NIST谱库定性和半定量分析重馏分油中的多环芳烃和烷基取代多环芳烃,并研究结构和烷基取代基对多环芳烃加氢转化的影响。结果表明,不同结构、不同烷基取代位置和不同烷基取代数量的多环芳烃的加氢转化率有很大区别。全二维气相色谱-飞行时间质谱具有高分辨能力和高灵敏度,是分析表征复杂样品中目标化合物的强有力工具,将在石油的分子水平表征领域发挥重要的作用     

渣油加氢处理后沥青质组成和结构的变化

采用IR、NMR、XPS等分析手段及钌离子催化氧化(RICO)法,考察了不同加氢反应温度下渣油沥青质组成和结构的变化。结果表明,随着加氢反应温度的升高,沥青质结构中硫质量分数降低,而氮质量分数增加,芳碳率提高;沥青质结构中出现较大的芳香核,芳香环上的取代侧链和芳环间的桥链均变短,分别由C₂₉降至C₁₇、C₂₁降至C₇;沥青质RICO产物中的苯多酸由苯甲酸、苯二甲酸为主逐渐变化为以苯四甲酸至苯六甲酸为主,说明沥青质中的群岛型结构有向大陆型结构转化的趋势。加氢温度升至450℃后,沥青质的组成和结构已基本稳定,说明渣油加氢适宜温度为450℃。     

胜利减压渣油强化热转化过程的研究

在实验室小型评价装置上考察了复合型增液剂L对胜利减压渣油热转化反应的影响。研究结果表明,增液剂L使热转化液体产物收率增加、焦炭和干气产率降低。增加的液体产物主要是蜡油馏分,其组成主要是3环以上的多环芳烃,说明增液剂可促进残渣油和重质生成油分子多环芳烃结构的烷基侧链和多环芳烃结构之间桥链的断裂,使3~4环的多环芳烃能够及时从反应器逸出而成为液体产品。气体产物中C3、C4烃收率增加、C1、C2烃收率减少,表明增液剂L改变了原料烃的热裂化方式。     

东濮凹陷西斜坡地区原油成熟度研究

采用GC-MS分析技术分析了东濮凹陷西斜坡胡状集和庆祖集油田原油芳烃化合物的成熟度参数,包括烷基二苯并噻吩(MDBT)系列、脱羟基维生素E和三芳甾烷(TAS)系列化合物.分析结果表明,芳烃化合物分布特征、脱羟基维生素E的β/γ异构体比值、4-/1-MDBT值、4,6-/1,4-DMDBT值、C₂₀/(C₂₀+C₂₆)TAS值以及三芳甾烷的相对含量,均反映东濮凹陷西斜坡二台阶构造带内的原油为烃源岩低熟阶段的产物,而长垣断层断裂带和长垣断层下降盘的原油属于烃源岩成熟阶段的产物.     

催化裂化柴油及其加氢产物中芳烃类型 与分子结构的表征

基于气相色谱-质谱(GC-MS)测定催化裂化柴油(LCO)及其加氢产物中芳烃的组成。根据色谱保留时间和质谱断裂特征,分析了LCO及其加氢产物中芳烃的类型与结构,并对C₉~C₁₁的C_nH_2n-8类及C_nH_2n-12类芳烃进行了分子结构鉴别。结果表明：C_nH_2n-8类芳烃在LCO中为具有五元环结构的茚满类,在加氢产物中既有四氢萘类,也有茚满类,后者可由前者发生异构化反应生成;C_nH_2n-10类芳烃在LCO中是以含有双键的环烷芳烃为主,如茚类、二氢萘类,在加氢产物中则是以含有饱和环结构的芳烃,如二环烷基苯类为主;LCO及其加氢产物中的C_nH_2n-16类芳烃均为芴类;萘类侧链的碳数、个数与位置均会影响其加氢转化率。此研究可为芳烃的选择性加氢以及后续加工提供信息。     

不同基属FCC油浆中芳烃结构组成分析

为实现催化裂化(FCC)油浆的高附加值利用,研究了不同油浆窄馏分中芳烃的结构和组成变化。以中间基属和石蜡基属FCC油浆的抽出油为原料,采用实沸点减压蒸馏切割得到7个窄馏分,以改进的Brown-Ladner(B-L)法和全二维气相色谱/飞行时间质谱为表征手段,考察了2种油浆各窄馏分中芳烃的结构组成变化。结果表明：中间基属的青岛炼化催化裂化油浆(QD-FCC油浆)以3~5环芳烃为主,而石蜡基属的兰州炼化催化裂化油浆(LZ-FCC油浆)以2~4环芳烃为主,石蜡基属LZ-FCC油浆的总饱和碳及环烷碳分率大于中间基属QD-FCC油浆。2种油浆中三环芳烃主要是渺位缩合的菲类和氢化苯并蒽类化合物;四环芳烃以渺位缩合的苯并蒽类化合物为主,且含有部分迫位缩合的芘类化合物;五环芳烃以迫位缩合的苯并芘类化合物为主,石蜡基属LZ-FCC油浆中的五环芳烃含量远远小于中间基属QD-FCC油浆。     

催化裂化轻循环油生产高辛烷值汽油或轻质芳烃(LTAG)技术关键及实践

基于对催化裂化轻循环油(LCO)烃类组成分子水平表征、LCO中稠环芳烃加氢反应规律和加氢LCO中四氢萘类单环芳烃的催化裂化与氢转移反应规律的认识,开发了将LCO高效转化为高辛烷值汽油或轻质芳烃的LTAG技术。LTAG技术是LCO加氢与催化裂化的集成技术,其技术关键是将LCO中稠环芳烃通过选择性加氢饱和反应生成四氢萘类单环芳烃,再通过强化加氢LCO中四氢萘类单环芳烃的催化裂化反应和抑制氢转移反应,实现LCO的高值化利用。加氢单元可采用LCO单独加氢或LCO与蜡油或渣油混合加氢模式;催化裂化单元可采用以下两种模式:①加氢LCO单独催化裂化生产高辛烷值汽油馏分或轻质芳烃;②加氢LCO与重油原料分层顺序进料催化裂化生产高辛烷值汽油馏分。LTAG技术对于炼油企业降低柴汽比、调整产品结构和提升产品质量提供了有力的支撑。该技术既解决了劣质LCO的出路问题,又弥补了市场短缺的高辛烷值汽油馏分或轻质芳烃的不足,具有显著的经济效益,在炼油企业得到广泛的应用。     

大庆、辽河油浆窄馏分的环状结构、组成的比较

选择大庆和辽河油浆为研究对象，采用超临界流体萃取分馏技术将其切割成窄馏分，运用常规分析方法结合质谱和核磁共振氢谱分析，得到大庆，辽河油浆窄馏分的饱和分中链烷烃和环烷烃的组成及芳香分中的环系组成，并得到了油浆窄馏分及其芳香分的平均结构，结果表明，大庆及辽河油浆窄馏分中芳香分中的各类环状结构随收率呈规律性变化，均以四环芳烃含量最多，辽河油浆窄馏分的芳香性高于对应的大庆油浆馏分。     

Additional Feedstock for Fluid Catalytic Cracking Unit

Fuel refineries are configured with Fluid Catalytic Cracking Unit (FCCU) to convert Vacuum Gas Oils (VGO) into higher value gasoline and middle distillates. But such refineries also generate 8-12% of heavy oils known either as decant oil or clarified oil (CLO), which has to be downgraded as furnace oil. The recycling of the decant oil into FCCU along with VGO feed is restricted to maintain the coke formation within design limits so that there is no decrease either in conversion or yield of liquid products from FCC operations. The condensed aromatic ring compounds present in CLO makes it undesirable feedstock for cracking, as it promotes heavy coke formation on the catalyst. Hence, CLO is disposed by absorbing in the residual fuel oils.

Of late, FCC units are being operated with higher severity to maximize gasoline, and this has resulted in much higher concentration of condensed aromatics in CLO. Hence, better utilization of CLO depends on separating its saturated hydrocarbon components as a good feedstock for recycling into FCCU with the simultaneous production of extract with enriched poly condensed aromatics as a value added product, namely Carbon Black Feed Stock (CBFS). This article describes several extraction studies carried out on CLO to obtain raffinate for which cracking studies were carried out in automated Micro Activity Test (MAT) unit. The quality of extract phase from each of the above studies was evaluated for its suitability as feedstock for carbon black.     

Kinetics of Hydrocracking and Hydrotreating of Coker and Oilsands Gas Oils

Two-stage hydrocracking of gas oils involves a complex set of hydrogenation, heteroatom removal, and cracking reactions. Feeds from coking processes and oilsands bitumen are richer in aromatics and heteroatoms, which increases the importance of the reactions of these components. The hydrocracking and hydrotreating kinetics of a series of conventional, coker and oilsands gas oils were measured using a laboratory microreactor. The kinetics were then correlated with the composition of the feed oils. The conversion of gas oil to middle distillate during hydrotreating was correlated with sulfur content and polyaromatic hydrocarbon content. Hydrocracking of the gas oil in the second stage of reaction followed a Langmuir-Hinshelwood rate expression based on the inlet concentration of total nitrogen. The resulting composite rate expression gave good prediction of gas oil conversion kinetics for the full range of gas oils. The inhibition of hydrocracking by nitrogen was more important for cracking than the differences in the homologous series in the gas oils of different origins.     

Additional Feedstock for Fluid Catalytic Cracking Unit

Abstract

Fuel refineries are configured with Fluid Catalytic Cracking Unit (FCCU) to convert Vacuum Gas Oils (VGO) into higher value gasoline and middle distillates. But such refineries also generate 8–12% of heavy oils known either as decant oil or clarified oil (CLO), which has to be downgraded as furnace oil. The recycling of the decant oil into FCCU along with VGO feed is restricted to maintain the coke formation within design limits so that there is no decrease either in conversion or yield of liquid products from FCC operations. The condensed aromatic ring compounds present in CLO makes it undesirable feedstock for cracking, as it promotes heavy coke formation on the catalyst. Hence, CLO is disposed by absorbing in the residual fuel oils.

Of late, FCC units are being operated with higher severity to maximize gasoline, and this has resulted in much higher concentration of condensed aromatics in CLO. Hence, better utilization of CLO depends on separating its saturated hydrocarbon components as a good feedstock for recycling into FCCU with the simultaneous production of extract with enriched poly condensed aromatics as a value added product, namely Carbon Black Feed Stock (CBFS). This article describes several extraction studies carried out on CLO to obtain raffinate for which cracking studies were carried out in automated Micro Activity Test (MAT) unit. The quality of extract phase from each of the above studies was evaluated for its suitability as feedstock for carbon black.     

变压器油结构组成对其氧化安定性与析气性的影响

以中海油环烷基常二线馏分油为原料,LH-23和RJW-2为加氢催化剂,采用不同加氢工艺制备变压器油基础油,分析了基础油结构组成对其氧化安定性与析气性的影响。结果表明:随着变压器油加氢反应温度升高,精制程度加深,基础油中饱和烃(总链烷烃和总环烷烃)的质量分数由64.2%增至80.6%,芳烃的质量分数由35.8%降至19.4%,氧化后的酸值逐渐降低,基础油的氧化安定性变好,但同时析气值逐渐增大,析气性变差;同时,基础油中多环芳烃质量分数由1.7%降至0,双环芳烃质量分数由12.0%降至2.6%,单环芳烃质量分数由22.1%降至16.8%,多环芳烃较单、双环芳烃对基础油氧化安定性的影响更大;在芳烃总碳原子质量分数(C_A值)为8.5%的基础油中加入萘的质量分数仅为1%时,油品的析气值由5.3 mm~3/min降至-3.5 mm~3/min,双环芳烃更适合改善基础油的析气性;为使变压器油基础油兼具良好的氧化安定性与析气性,基础油的C_A值应保持在9%～13%。     

Catalyst Deactivation, Kinetics, and Product Quality of Mild Hydrocracking of Bitumen-Derived Heavy Gas Oils

To assess mild hydrocracking as an option to improve the quality of the heavy gas oil (HGO) fraction of Syncrude's synthetic crude oil (known as Syncrude Sweet Blend or SSB), severe hydrotreating tests were performed by using Athabasca oilsands bitumen-derived coker HGO, heavy vacuum gas oil, and a blend of the two in a pilot-scale down-flow reactor over a typical commercial NiMo/Al₂O₃ hydrotreating catalyst. Kinetics of sulfur and nitrogen removal, 343°C+ conversion, and aromatics hydrogenation were investigated by incorporating the effect of catalyst deactivation. The total liquid products (TLPs) from the pilot tests were distilled into naphtha, light gas oil (LGO), and HGO fractions, and the TLPs and distilled products were characterized. Cetane number (CN) was determined by engine test for selected LGOs and by ignition quality tester for all LGOs. The quality of product HGOs as fluid catalytic cracking (FCC) unit feedstock was evaluated by using correlations (developed based on feed properties including GC-MS data) to predict FCC product yields. The CN of the LGOs and the predicted gasoline yields from HGO products were much better than that produced from the corresponding fractions of current SSB. The CN and FCC gasoline yield were related to the level of 343°C+ conversion (i.e., the higher the conversion, the higher the CN and FCC gasoline yield).     

Kinetics of Hydrocracking and Hydrotreating of Coker and Oilsands Gas Oils

Abstract

Two-stage hydrocracking of gas oils involves a complex set of hydrogenation, heteroatom removal, and cracking reactions. Feeds from coking processes and oilsands bitumen are richer in aromatics and heteroatoms, which increases the importance of the reactions of these components. The hydrocracking and hydrotreating kinetics of a series of conventional, coker and oilsands gas oils were measured using a laboratory microreactor. The kinetics were then correlated with the composition of the feed oils. The conversion of gas oil to middle distillate during hydrotreating was correlated with sulfur content and polyaromatic hydrocarbon content. Hydrocracking of the gas oil in the second stage of reaction followed a Langmuir-Hinshelwood rate expression based on the inlet concentration of total nitrogen. The resulting composite rate expression gave good prediction of gas oil conversion kinetics for the full range of gas oils. The inhibition of hydrocracking by nitrogen was more important for cracking than the differences in the homologous series in the gas oils of different origins.     

Evaluation of hydrocarbon contaminants in olives and virgin olive oils from Tunisia

The present paper investigated on the presence of some hydrocarbon contaminants, namely polycyclic aromatic hydrocarbons (PAHs), mineral oil hydrocarbons (MOH) comprising saturated (MOSH) and aromatic (MOAH) compounds, and polyolefin oligomeric saturated hydrocarbons (POSH) in olives and extra virgin olive oils from Tunisia. Olive fruits were collected in sites exposed to different environmental contamination, and the oil extracted both by physical mean (using an Abencor extractor) and with solvent (using microwave assisted extraction, MAE). Analytical determination was performed by SPE cleanup on silica cartridge followed by spectrofluorometric detection, for PAH, and on-line HPLC-GC-FID for MOH and POSH. Oils extracted from olives by physical mean, as well as extra virgin olive oils from the market, had PAH levels never exceeding the EU legal limits. All olive samples showed similar MOSH profiles, but not clear correlation between the variable contamination levels and considered sources of contamination, was evidenced. The average MOSH content in oil extracted from olives by solvent (11.1 mg/kg) was about four time higher than in oil extracted by physical mean (2.6 mg/kg). MOSH in extra virgin oil from the market ranged from 10.3 to 38.0 mg/kg, while MOAH were not detected. The higher MOSH levels found in oils from the market evidenced an important contribution due to oil processing and/or packaging. Two of the samples were clearly contaminated with polyolefin oligomeric hydrocarbons (POSH) migrated from the plastic cap.     

催化裂化轻循环油生产轻质芳烃的分子水平研究

从分子水平研究了催化裂化轻循环油（LCO）经加氢处理后进行催化裂化生成苯、甲苯、二甲苯和乙苯等轻质芳烃（BTXE）的反应规律。认为加氢LCO中重质单环芳烃（包括烷基苯和环烃基苯）的含量及催化裂化反应条件是影响轻质芳烃产率的关键,适宜的加氢处理深度(加氢LCO氢质量分数为11.00%)、催化裂化较高的反应温度（大于550 ℃）和较大的剂油比（大于8）有利于生产轻质芳烃。在实验条件范围内,LCO中环烃基苯的表观裂化反应比例大于73.4%,表观缩合反应比例小于14.7%,表观未转化比例小于15.0%,且高温有利于LCO中环烃基苯的裂化反应。加氢LCO经催化裂化反应生成轻质芳烃的单程产率可达14.3%,约占催化裂化产物中单环芳烃总量的1/3。