活性氧化铝吸附脱除模拟油中吡啶的研究

分别采用碱性、酸性、中性氧化铝吸附脱除氮质量分数为1 732μg/g的模拟油(吡啶的正十二烷溶液)中的吡啶,确定最佳吸附剂,并探究各因素对其吸附脱氮效果的影响。结果表明：在处理15 mL模拟油时,使用1.2 g碱性氧化铝在303 K下吸附30 min的吸附脱氮效果最佳,氮去除率为61.24%;碱性氧化铝对模拟油中吡啶的吸附行为符合Langmuir-Freundlich混合模型,该吸附过程可自发进行,属于放热物理吸附,吸附过程符合准一级动力学模型;经过高温焙烧和乙醇洗涤的碱性氧化铝吸附剂,再生率分别为72.04%和71.48%,说明碱性氧化铝具有良好的再生性能。     

Adsorption of nitrogen compounds from diesel fuels over alumina-based adsorbent towards ULSD production

The aim of this work is to estimate some nitrogen (N)-adsorption properties and the N-adsorption capacity (q) required for commercial application in the ultra-low sulfur diesel production. Hydroxyl (OH) groups and interactions among the commercial adsorbent Selexsorb® CDX (CDX) and pyridine and indole were studied by means of Fourier transform infrared spectroscopy. The adsorption of N-compounds from three diesel fuels over CDX was estimated at CDX/fuel ratio: 0.01–0.09 g/g, Contact time: 1–60 m, 303 K, and 0.078 MPa in a batch setup. It was concluded that an appropriate N-adsorbent should have high densities of suface OH groups and Lewis and Brønsted strong-acid sites and a q ≥ 0.70 mmol/g.     

杂原子介孔分子筛Ba-MCM-41的制备及其吸附脱氮性能

采用水热合成法制备了介孔MCM-41和Ba-MCM-41分子筛,并利用X射线衍射、N2吸附-脱附、傅里叶变换红外光谱对介孔MCM-41和Ba-MCM-41分子筛进行了表征.将Ba-MCM-41分子筛用于对模拟油的静态吸附脱氮试验,结果表明,当模拟油用量为15 mL时,较适宜的吸附脱氮条件为分子筛用量0.3 g、吸附温度...     

Nitrogen Compound Distribution of Refined Middle Distillate Fuels

Abstract

Three middle distillate fuels originating from New Zealand, Venezuela, and Texas were studied to determine the nitrogen compound distribution in each fuel. Organo-nitrogen compounds in the fuels were isolated by mild acid extraction followed by silica gel adsorption. The extraction scheme yielded three extracts for each fuel—a basic nitrogen extract in methylene chloride, a non-basic nitrogen extract in methyl alcohol, and a non-basic nitrogen extract in methylene chloride. The major constituents of each extract were identified by gas chromatography/mass spectrometry (GC/MS).     

Absorptive Denitrogenation of Diesel Oil Using a Modified NaY Molecular Sieve

Y molecular sieve, modified by NH₄⁺, Zn²⁺, Cu²⁺, or Cr³⁺, were characterized by X-ray diffraction, infrared spectrum, and nitrogen adsorption, and used to adsorb denitrogenation from model fuel containing quinoline and diesel oil. The molecular size of quinoline, calculated by using density functional theory, was 7.116×5.002 Å, implying that it does not access easily to 7.4 Å microporous pores of Y molecular sieve. The adsorption denitrogenation of CrY was the best due to some mesoporous pores, followed by CuY, ZnY, and NH₄Y, implying that the absorption denitrogenation related to valence state metal ion, the better adsorption denitrogenation performance, the higher valence of metal ions. The basic nitrogen removal of diesel oil on CrY, CuY, ZnY, or NaY is 56.58%, 60.16%, 37.41%, and 23.72%, respectively.     

Nitrogen Compound Distribution in Refined Middle Distillate Fuels

Abstract

Three diverse middle distillate fuels from Mobile, Alabama, Jacksonville, Florida, and Kirachi, Pakistan were analyzed to quantify the organic nitrogen compound distribution in each. Organo-nitrogen compounds were isolated by a mild acid extraction followed by a silica-gel adsorption procedure. The extraction process yielded three extracts for each fuel: a basic nitrogen extract in methylene chloride, a nonbasic nitrogen extract in methylene chloride, and a nonbasic nitrogen extract in methanol. The major compounds in each extract were identified by gas chromatography/mass spectrometry (GC/MS).     

变色硅胶对模拟柴油中喹啉或吡啶的吸附行为研究

采用XRD、FT-IR、低温N2吸附-脱附和NH3-TPD等方法对硅胶和变色硅胶进行了较详细的表征。XRD和FT-IR表征结果表明硅胶和变色硅胶都具有非晶态结构。硅胶和变色硅胶的平均孔径分别为18.46 nm和1.80 nm,BET比表面积分别为437.86 m2/g和623.39 m2/g,孔体积分别为0.972 4 cm3/g和0.344 2 cm3/g。NH3-TPD的表征结果表明变色硅胶的酸性远大于硅胶的酸性。研究了氧化铝、硅藻土、硅胶及变色硅胶对模拟柴油中的喹啉的吸附脱除效果,结果表明,变色硅胶吸附脱除喹啉的效果远远好于其它吸附剂,较强的酸性大大增强了变色硅胶吸附脱除碱性氮化物喹啉的能力。进一步研究了变色硅胶吸附脱除模拟柴油中的喹啉或吡啶的动力学,结果表明：喹啉和吡啶在变色硅胶上的吸附等温线均属于S型;采用Freundlich（F型）和Langmuir（L型）方程对喹啉吸附数据拟合所得到的R值几乎相同,说明变色硅胶吸附喹啉的动力学符合L型和F型混合模型;对吡啶数据拟合所得Freundlich方程的R值远大于Langmuir 方程的R值,说明变色硅胶吸附吡啶更接近于F型模型。     

吸附剂表面性质对柴油碱性氮化物吸附脱除的影响

对硅胶、改性硅胶、活性白土和γ-Al2O3四种吸附剂进行柴油吸附脱除碱性氮化物试验以及BET分析和吡啶吸附红外分析。结果表明,室温下硅胶在拐点前的碱性氮化物吸附等温式为： ;改性硅胶吸附碱性氮化物的吸附等温式为： ;γ-Al2O3的碱性氮化物吸附等温式为： ;活性白土的碱性氮化物吸附等温式为： 。研究发现,吸附剂比表面积不是吸附脱除柴油碱性氮化物的主要影响因素,孔径小于3.5nm时会阻碍碱性氮化物在吸附剂表面的扩散,降低吸附剂吸附容量。碱性氮化物在吸附剂表面的吸附作用以化学吸附为主, 随着吸附剂表面酸中心增加,吸附剂对碱性氮化物的吸附容量增加。     

Performance Evaluation of (Ethylene-co-Vinyl Acetate) Copolymers as Pour Point Reducing Agents for Petroleum Middle Distillates

Abstract

Petroleum, as well as its middle distillate fractions (boiling between 150–400°C), shows a tendency to crystalize paraffin molecules whenever temperature is lowered below the cloud point. Paraffin deposition may occur in storage tanks, pipelines, or conduits, this leading to the impairing of fluid pumping, even with filter plugging of diesel engines. Such drawback may be overtaken by the addition of chemical compounds aiming at inhibiting paraffin deposition. Such inhibitors are not universally effective, since they are operational for a certain molecular weight interval only. This work relates the performance evaluation of commercial poly(ethylene-co-vinyl acetate) samples of varied molecular weights resulting from mechanical shear experiments. Samples included one kind of diesel oil and three kinds of base lube oils: light neutral, medium neutral, and heavy neutral or bright stock oils. Results indicated that mechanical shear was effective only for samples containing 10% w/w of vinyl acetate. Additive performance as lube oil pour point reducing agents is a function of the copolymer composition only for samples the molecular weight of which is compatible with the molecular weight of the oil paraffins.     

THE SYNTHESIS OF A REACTIVE PYRIDINE INTERMEDIATE FOR FUEL INSTABILITY STUDIES

ABSTRACT

Pyridine compounds have been found in significant concentration in middle distillate fuels. These compounds have been implicated in fuel instability reactions and could also be involved in color body formation. Few pyridine compounds are commercially available and those that are available are relatively simple in structure. We report the synthesis of a reactive pyridine intermediate, l-carbethoxy-2-cyano-1,2-dihydropyridine, that could be used for a wide range of further pyridine compound synthesis including pyridines, and many other alkyl derivatives. This particular compound has been reported, but in very low yield. This reported improved synthetic procedure give yields in excess of 90%.     

二乙烯苯基共聚物的合成、表征和二氧化碳吸附性能

采用溶剂热方法合成了介孔聚合吸附材料,利用扫描电子显微镜(SEM)、氮气吸附仪(BET)、红外光谱仪对合成的吸附材料进行了表征,并通过CO2吸附评价实验研究了不同聚合条件、不同工艺条件对CO2吸附性能的影响。结果表明:聚二乙烯苯氨基化产物(Ⅰ)、二乙烯苯与4-乙烯吡啶共聚物(Ⅱ)、二乙烯苯与1-乙烯咪唑共聚物(Ⅲ)均为介孔结构,比表面积在200m2/g~800m2/g,孔径在20nm~50nm;其CO2吸附能力的顺序为:Ⅲ>Ⅰ>Ⅱ。     

甲苯和吡啶对Ag/TiO2-NaY吸附脱硫性能的影响

 以溶胶-凝胶法制备了TiO₂-NaY(TY)分子筛载体,采用浸渍法制备了Ag/TiO₂-NaY(AgTY)吸附剂,并用X射线衍射、傅里叶变换红外光谱和X射线光电子能谱技术对吸附剂进行了表征。在固定床吸附床上考察了含氮化合物和芳香族化合物对AgTY选择性吸附噻吩（TP）和苯并噻吩（BT）性能的影响,并研究了其吸附机理。结果表明,AgTY吸附剂中TiO₂主要以锐钛矿型存在,与NaY相比,TY分子筛的骨架结构并未发生明显的改变;在吸附温度50℃时,AgTY吸附剂对噻吩、苯并噻吩的穿透硫容分别为0.45%和0.63%;对噻吩模拟油,吡啶对吸附脱硫影响比甲苯的影响大,而对于苯并噻吩模拟油,甲苯的影响比吡啶的影响大。噻吩类硫化物与AgTY吸附剂之间主要以π络合及S—M配位作用机理吸附。     

Nitrogen Compound Distribution of Refined Middle Distillate Fuels

Three middle distillate fuels originating from New Zealand, Venezuela, and Texas were studied to determine the nitrogen compound distribution in each fuel. Organo-nitrogen compounds in the fuels were isolated by mild acid extraction followed by silica gel adsorption. The extraction scheme yielded three extracts for each fuel—a basic nitrogen extract in methylene chloride, a non-basic nitrogen extract in methyl alcohol, and a non-basic nitrogen extract in methylene chloride. The major constituents of each extract were identified by gas chromatography/mass spectrometry (GC/MS).     

CHEMICAL FACTORS AFFECTING INSOLUBLES FORMATION IN SHALE DERIVED DIESEL FUEL

Detrimental changes in fuel properties with time have been a continuing problem in the use of middle distillate fuels. Instability of diesel fuels is usually defined by the formation of insoluble sediments and gums. Gravimetric stability tests have been conducted at 43° and 80°C, respectively, using three model nitrogen heterocycles, 2-methylpyridine, 2,6-di methyl quinoline, and dodecahydrocarbazole, as dopants in an otherwise stable shale diesel fuel. Potential interactive effects have been defined for these three model nitrogen heterocycles in the stable fuel in the presence of a second model dopant, t-butyl hydroperoxide. 2-Methyl pyridine and 2,6-dimethyl quinoline were inactive and only 2-methyl pyridine showed slight positive interactive effects. Dodecahydro-carbazole formed large amounts of insolubles by itself and exhibited positive interactive effects.     

INVESTIGATION OF NITROGEN COMPOUND TYPES IN HIGH-BOILING PETROLEUM DISTILLATES FROM SAUDI ARABIAN CRUDE OILS

ABSTRACT

Acids, bases and neutral nitrogen compounds from high-boiling petroleum distillates were separated and further fractionated into fractions containing nitrogen compound types by HPLC on neutral alumina. Acids and bases were separated with anion and cation exchange resins respectively while the neutral nitrogen compounds were removed by complexation with ferric chloride supported on Attapulgus clay. The HPLC fractions were characterized by potentiometric titration for their basic and nonbasic nitrogen contents while infrared spectroscopy was used for the quantitative determination of major compound types present which are pyridines, pyrroles, amides, phenols and carboxylic acids. Characterization of individual nitrogen compounds was accomplished using gas chromatography and gas chromatography -mass spectrometry. The nitrogen compounds identified belong to three compound types which are pyridine, pyrrole and amide.     

ANALYSIS OF ORGANIC MATERIAL DIFFICULT TO RECOVER FROM OIL SHALE

Green River oil shale was supercritically treated with methanol and water and then extracted with benzene and methanol to recover approximately 85% of the organic matter in the shale. The spent shale was then extracted with pyridine to recover an additional 2-31% of the organic matter that remained on the shale. The liquid organic material extracted with pyridine contained some of the compound types most difficult to recover from shale. These materials were characterized. High-molecular nitrogen compounds of the pyridine type were found to be a predominant compound class in the pyridine extract. The pyridine-extracted material contained a higher percentage of nitrogen than a Fischer assay oil and a lower percentage of hydrogen than a Fischer assay oil indicating that more aromatic nitrogen compounds were present in the pyridine extract than in Fischer assay oil. Bonding mechanisms between organic and inorganic components of the shale were studied as were spectroscopic data showing the nature of the organic material remaining on spent shale after extraction with pyridine.     

Ni-MCM-41分子筛合成及其对模拟柴油吸附脱氮性能研究

以十六烷基三甲基溴化铵为模板剂、以硝酸镍为镍源,采用水热合成法合成Ni-MCM-41杂原子分子筛,并对其进行红外光谱（IR）、X射线衍射（XRD）及N2吸附-脱附表征。IR和XRD结果表明样品具有MCM-41分子筛的介孔结构,镍离子已进入分子筛骨架,N2吸附-脱附结果得出Ni-MCM-41杂原子分子筛的比表面积为523 m2/g,平均孔径为2.82 nm,孔体积为0.625 8 cm3/g。研究了Ni/SiO2摩尔比对分子筛吸附脱除含吡啶模拟柴油碱性氮化物的影响,确定Ni/SiO2摩尔比为0.01的Ni-MCM-41分子筛吸附脱氮效果最佳。考察了分子筛用量、吸附温度、吸附时间对Ni-MCM-41（0.01）分子筛吸附脱氮性能的影响,结果表明最佳吸附脱氮条件为：分子筛用量为0.02 g/mL（相对于模拟柴油）,吸附温度为40 ℃,吸附时间为20 min。     

氮取代对环状烃在H-FAU分子筛中吸附性能的影响

催化裂化原料中的含氮杂环化合物吸附能力强、扩散阻力大,是造成分子筛催化剂中毒失活的重要因素。选取吡啶和哌啶两种含氮杂环化合物及与其结构相似的苯和环己烷两种环状烃为模型化合物,采用蒙特卡罗（GCMC）和密度泛函（DFT）方法考察了4种化合物在H-FAU分子筛孔道和酸性位上的吸附行为。结果表明：4种分子主要分布在超笼孔道中,其中两种氮化物的分布更加集中;吸附强度由高到低的顺序为：哌啶＞吡啶＞苯＞环己烷,并且氮化物与分子筛活性位之间是化学吸附,苯和环己烷的吸附是物理吸附。电荷密度分布结果揭示了两种氮化物分子与H质子之间发生不同程度的电荷转移。模拟结果可为分子筛催化剂氮中毒机理的研究提供理论指导。     

分子磁强化磁分离法脱除柴油中的碱性氮化合物

用氨水作沉淀剂与一定量的Fe2+和Fe3+反应制备了具有磁性的碱性氮脱除剂，考察了其对柴油中碱性氮的脱除效果，研究了外加磁场对碱性氮脱除效果的影响。结果表明：在外加磁场的作用下，油品中的含氮碱性化合物分子的磁矩加大，有利于在磁性物质上的吸附，可以大大提高碱性氮的脱除率。对碱性氮浓度为65.6μg.g-1模拟油样品，在0℃，反应时间10min，剂油比0.06，螺线管磁场电流强度为5A的条件下，碱性氮的脱除率可达到94%，油品收率高于99.4%，对碱性氮含量为65.6μg.g-1的实际柴油样品，其碱性氮脱除率可达90.1%。这种磁强化吸附技术在清洁燃料油生产中具有一定的应用前景。     

THE EXTRACTION OF COALS WITH PYRIDINE AND TOLUENE AT 350°C

ABSTRACT

The extraction of three coals with mixtures of toluene and pyridine at 350^°C were compared. The conversion of both the bituminous and sub-bituminous coals Increased as the amount of pyridine in the mixture Increased up to ca 60% pyridine at a constant gas density of 0.64 g/ml. However, there was no Improvement in conversion for the brown coal when toluene was replaced with pyridine. The difference between pyridine and toluene conversion decreased as the gas density decreased. The high solvent efficiency of pyridine is probably due to the unshared pair of electrons on the nitrogen atom. Addition of other compounds with an unshared pair of electrons on a nitrogen or an oxygen atom also Increased conversion In toluene supercritical gas extraction of a bituminous coal at 350^°C and a constant solvent density.