柴油脱硫的机理研究以及反应中的溶剂效应

柴油的脱硫技术分为加氢脱硫和非加氢脱硫。在非加氢脱硫的研究中,氧化脱硫技术具有反应条件温和、不使用昂贵的氢气、投资和操作费用低等优点日益受到重视。文章介绍了柴油的脱硫技术的机理方面的研究进展。其中包括加氢脱硫的反应网络;以及氧化脱硫研究中,光化学氧化体系和有机过氧化物氧化体系中DBT的氧化机理。在不同的反应体系中,溶剂对含硫化合物的脱除也有很大的影响.     

二苯并噻吩在分散型钼催化剂和原位产生的氢存在下的加氢脱硫 Ⅳ.集总动力学

研究了水/甲苯乳化液中二苯并噻吩(硫芴)在分散型钼酸、磷钼酸和四硫代钼酸铵催化剂存在下的加氢脱硫反应.反应在高压釜中于340℃及三种不同的气氛即H2,H2/H2O和CO/H2O(CO和H2O经水煤气转换反应(WGSR)产生原位氢)的存在下进行.用GC和GC-MS鉴定、分析了气体和液体产物的组成.在此基础上,提出了包含直接氢解和加氢脱硫两个反应途径的硫芴加氢反应网络,并采用最优化法计算了反应网络的速率常数.结果表明:对所研究的9个反应体系,反应网络的模型预测值与试验值十分吻合;加氢路径比氢解路径至少快1倍,硫芴的加氢比联苯的加氢快1倍,部分加氢的中间产物1,2,3,4-四氢硫芴和1,2,3,4,10,11-六氢硫芴的氢解比硫芴直接氢解快10倍以上;对硫芴的加氢脱硫反应,在分散型钼存在下,原位产生的氢比加入的氢气更为有效.     

二苯并噻吩在分散型钼催化剂和原位产生的氢存在下的加氢脱硫 Ⅱ.原位氢和分子氢的比较

研究了水/甲苯乳化液中二苯并噻吩(硫芴)在分散型钼酸、磷钼酸和四硫钼酸铵催化剂存在下的加氢脱硫反应.反应在高压釜中于340℃及三种不同的气氛即H2,H2/H2O和CO/H2O(CO和H2O经水煤气转换反应(WGSR)产生原位氢)的存在下进行.用GC和GC-MS鉴定、分析了气体和液体产物的组成.结果表明:对硫芴的加氢脱硫反应,在分散型钼酸和磷钼酸存在下,原位产生的氢比加入的分子氢更为有效.动力学研究结果表明:WGSR反应比硫芴的加氢脱硫反应快5～10倍,说明在原位氢存在下硫芴的加氢脱硫反应是速度控制步骤.总之,试验结果证实,在分散型催化剂和原位氢存在下的加氢过程是重油乳状液改质和破乳的有效方法.     

气相色谱-原子发射光谱联用技术测定柴油中硫化物

采用气相色谱－原子发射光谱（GC－AED）联用技术对柴油中硫化物进行了定性定量研究，考察了柴油加氢脱硫处理前后硫化物的变化及不同柴油原料硫化物的分布情况。结果表明，1＃柴油可定性出33类硫化物，经加氢脱硫处理后，1－1＃和1－2＃样品硫含量可由1497mg/L分别降到165.1mg/L和90.4mg/L，平均脱除率为89.0%和94.0%。其中噻吩或苯并噻吩的脱除率为100％；C1二苯并噻吩的肿除率为90.0%和96.2%;C2二苯并噻吩的脱除率为80.6%和91.7%；C3二苯并噻吩的脱除率为72.6%和84.4%；C4二苯并噻吩的脱除率为79.0%和90.3%;C5或C6二苯并噻吩的脱除率为58.4%和68.4%；未知硫化物脱除率95.7%和97.9%。噻吩类脱除率视取代基的大小、个数和取代位置的不同脱除率不同；不同原料 总硫和各种硫化物含量差别很大，应根据其硫化物的分布特点，有针对性地研制开发加氢脱硫的催化剂及选择合适的加工工艺。     

二苯并噻吩在分散型钼催化剂和原位产生的氢存在下的加氢脱硫 Ⅰ.产物分布和反应网络

研究了水/甲苯乳化液中二苯并噻吩(硫芴,DBT)在分散型钼酸和磷钼酸催化剂存在下的加氢脱硫反应.反应在高压釜中于340℃及经水煤气转换反应(WGSR)产生的原位氢存在下进行.用GC和GC-MS 鉴定、分析了气体和液体产物的组成.结果表明:在反应过程中部分加氢的中间产物1,2,3,4-四氢硫芴(4H-DBT)和1,2,3,4,10,11-六氢硫芴(6H-DBT)的浓度相当高,但二联苯的浓度相对较低,说明加氢路径与氢解路径相当.提出的硫芴加氢脱硫反应网络包含两个反应途径:噻吩环先直接氢解脱硫,紧接着苯环加氢途径;苯环先加氢,然后噻吩环氢解脱硫途径.同时,还包含环烷环的异构化反应.     

柴油馏分加氢脱硫动力学及反应器研究进展

当前各国环保法规对柴油中硫的质量分数的限制越来越严格。催化加氢脱硫是实现柴油低硫化的重要途径，动力学和新反应器的研究受到了研究者的广泛关注。本文介绍了柴油馏分中两种典型的难脱除含硫化合物二苯并噻吩和4,6-二甲基二苯并噻吩在各类催化剂上加氢脱硫的反应路径，比较了这两种模型含硫化合物的直接脱硫（DDS）和先加氢再脱硫（HYD）路径相对快慢的影响因素。详细综述了假1级、假2级、快慢1级、n级、L-H以及抑制剂H2S存在下的动力学模型在描述二苯并噻吩类模型化合物及真实油品的加氢脱硫过程中的研究现状，介绍了神经网络在柴油加氢动力学和脱硫率预测方面的研究进展。还对催化精馏、并流-逆流滴流床、两相床反应器等新型加氢脱硫反应器的最新发展作了综述，展望了加氢脱硫动力学及反应器的研究方向和面临的挑战。     

催化加氢热解/气相色谱-质谱研究沉积物中生物标志物

针对地质体中高演化沉积有机质，应用催化加氢热解/气相色谱-质谱方法测定了干酪根中以共价键结合的生物标志物。结果表明，实验样品的催化加氢热解产物收率明显高于二氯甲烷（DCM）索氏抽提，产物色谱图中饱和烃的峰形、保留时间和质谱特征与索氏抽提峰形基本一致；对比两种方法产物中饱和烃主要指标甾烷m/z 217和藿烷m/z 191表明，经过加氢还原，干酪根分子网络中共价键结合着两种生物标志物分子骨架得到印证，为催化加氢热解提取沉积物中生物标志物的方法可靠性提供了依据。催化加氢热解/气相色谱-质谱技术是一种对研究高演化沉积有机质中生物标志化合物有独特作用的有效分析手段。     

高硫煤加氢热解脱硫的研究Ⅱ.反应条件对煤加氢热解脱硫的影响

本文采用红庙褐煤在加压固定床上，详细考察了不同反应条件对加氢热解脱硫的影响。研究结果表明：氢气流速的增加可以显著降低焦中的硫含量，增加脱硫率和硫在气相中的分布。氢气压力增加有利于增加煤中含硫化合物的加氢脱硫反应，提高脱硫率。加氢热解过程中的传质作用对脱硫率和硫分布也有重要影响。在一定的热解温度下，适当增加停留时间有利于氢气与含硫化合物的扩散接触，提高脱硫率。同时红庙煤加氢热解产生的焦油中的硫分布随各种反应条件的变化不大。     

柴油在超声波/Cu2+/H2O2中的氧化脱硫

为了实现生产低硫柴油和超低硫柴油的目标，以超声波为外加能源，构筑超声波/类Fenton试剂的柴油氧化脱硫反应体系，考察了水相pH值和超声功率这两个参数对柴油氧化脱硫效果的影响。实验结果表明，当类Fenton试剂的水相pH值为2.00左右时，其脱硫效果较好；无超声波下H2O2、类Fenton试剂、超声波/H2O2及超声波/类Fenton试剂的柴油氧化脱硫反应符合表观一级反应动力学规律。超声波功率的提高对氧化脱硫有明显的促进作用,这主要是由于功率的增加，有助于加速空穴的形成与内爆，从而促进反应的进行。     

轻质油品非加氢脱硫技术*

日益严格的环保法规,对生产低硫、超低硫清洁油品技术提出了更高的要求。传统的加氢脱硫技术存在投资大、运行成本高等问题,因此开发成本低、操作条件温和的非加氢脱硫技术成为一种趋势。本文综述了目前轻质油品非加氢脱硫的相关技术,主要包括氧化脱硫、吸附脱硫和生物脱硫等技术的研究进展;简要介绍了萃取脱硫、络合脱硫、催化裂化脱硫、烷基化脱硫、膜分离脱硫及离子液体脱硫等技术;同时对轻质油品非加氢脱硫技术的应用前景进行了展望。     

Determination of elemental sulfur in coal by gas chromatography-mass spectrometry

A method for the determination of S0 in coal based on the extraction with cyclohexane with subsequent quantitative analysis of elemental sulfur in the extract by GC/MS is described. The quantity of elemental sulfur was determined in four coal samples with different distribution of sulfur forms. The effect of solvent and extraction time on the efficiency of sulfur removal was studied. The elemental sulfur extracted from coal occurred in the form of S6, S7 and S8. Calibration solutions were prepared from freshly recrystalized elemental sulfur. It was found that the injection temperature has a crucial influence on the m/z 64 ion chromatogram.     

仿刺参中皂苷类成分的高效液相色谱指纹图谱

利用高效液相色谱法建立了仿刺参皂苷类成分的指纹图谱,为仿刺参的质量控制提供了新的方法。采用固相萃取制备供试品溶液,选用Zorbox SB-C18色谱柱(250 mm×4.6 mm, 5 μm),以乙腈-0.1%磷酸水溶液为流动相进行梯度洗脱,检测波长为205 nm,柱温30 ℃。分析了不同产地的10批仿刺参样品,采用国家药典委员会推荐的“中药色谱指纹图谱相似度评价系统(2004 A版)”处理谱图,确定了6个共有峰。计算了10个样本间的指纹图谱相似度,所得相似度计算结果均大于0.97。该方法具有良好的稳定性和重现性,可用于仿刺参的质量控制。     

石墨电极上硫化钠的阳极氧化机理探索

电解硫化氢气体的碱性吸收液（Ｎａ２Ｓ表示）产生单质硫和氢气的研究是治理硫化氢废气的一种新方法［１ -７］,较之Ｃｌａｕｓ法有许多优点［３,４］,这对环境保护和资源回收均具有重要的实际意义．文献对硫化物水溶液电化学氧化机理的研究主要着重于在某些贵金属阳极上,包括某些硫化矿的湿法冶金反应过程的研究［８,９］,光电化学电池中使用多硫化物的研究［１０ -１３］,以及硫化物电解时产生单质硫的电催化活性研究［１４］等 ;但在石墨阳极上硫化物电化学氧化机理的研究报导却很少［３,４］．本文研究在石墨阳极上硫化钠水溶液…     

煤在不同O2/CO2气氛下燃烧硫析出特性研究

研究了煤在不同氧体积分数、混有CO2气氛下燃烧硫析出特性，结果表明，煤在低氧、混有CO2气氛下燃烧，SO2和H2S析出速率曲线均呈现双峰结构，H2S析出率明显增大，硫析出时间延长；在高氧气氛下，SO2和H2S析出速率曲线均呈现单峰结构，硫析出时间缩短。煤在低氧体积分数、混有CO2气氛下燃烧能够改善煤灰自固硫能力，降低硫的最终析出率；煤在高氧体积分数、混有少量CO2气氛下燃烧与空气气氛下燃烧相比，硫的最终析出率无明显变化。     

氧化-萃取脱除柴油中噻吩类硫化物研究进展

近年来针对柴油中噻吩类硫化物的脱除问题国内外进行了多种非加氢脱硫技术研究,其中氧化脱硫、萃取脱硫、氧化-萃取脱硫技术是研究较多、具有应用前景的脱硫方法。本文从柴油氧化-萃取脱除噻吩类硫化物的反应机理出发,重点概述了有机酸、酸酐催化体系、离子液体催化体系及分子筛催化体系氧化-萃取脱除噻吩类硫化物获得低硫柴油的最新研究成果,并提出了目前存在的问题及该领域未来的研究方向。     

Determination of elemental sulfur in coal by gas chromatography – mass spectrometry

A method for the determination of S⁰ in coal based on the extraction with cyclohexane with subsequent quantitative analysis of elemental sulfur in the extract by GC/MS is described. The quantity of elemental sulfur was determined in four coal samples with different distribution of sulfur forms. The effect of solvent and extraction time on the efficiency of sulfur removal was studied. The elemental sulfur extracted from coal occurred in the form of S₆, S₇ and S₈. Calibration solutions were prepared from freshly recrystalized elemental sulfur. It was found that the injection temperature has a crucial influence on the m/z 64 ion chromatogram.     

Determining the antioxidant activities of organic sulfides by rotary bomb oxidation test and pressurized differential scanning calorimetry

Several typical sulfides were selected and dissolved in hydrotreated base oil, and the antioxidant activities of sulfides studied by rotary bomb oxidation test (RBOT), isothermal pressurized differential scanning calorimetry (PDSC) and non-isothermal PDSC. Four characteristic indexes of constant heating-rate PDSC were chosen and normalized to a comprehensive index by a new method. The sequence determined by the comprehensive index accords partly to the sequence determined by RBOT and accords well with the results reported. The antioxidant activity of sulfide increases with the number of sulfur atoms. Sulfide with long chain has good antioxidant activity, and the antioxidant activity of cyclic sulfides is poor. The method of normalizing the data is useful to determine the oxidation performances of samples, especially when the antioxidant activities vary greatly.     

Capillary electrophoretic separation of inorganic sulfur-sulfide, polysulfides, and sulfur-oxygen species

A CE protocol was developed for the identification and separation of inorganic polysulfides simultaneously with other inorganic sulfur-bearing species coexisting in aqueous hydrosulfide/sulfur solutions. The electrophoretic separation of thiosulfate, sulfate, hydrosulfide, sulfite, tetrathionate, and polysulfides was achieved at pH values between 8.2 and 12.2. The peaks attributed to the polysulfide species were strongly sensitive to pH. CE analysis of hydrosulfide/sulfur solutions at different pH values permitted possible identification of two forms of polysulfides: S4(2-) and S3(2-). Upon exposure to air at ambient temperature, thiosulfate was the main oxidation product of hydrosulfide/sulfur solutions mainly in the first 60 min, when hydrosulfide was rapidly consumed. Analysis of the oxidation reaction products provided retrospectively tentative evidence that the peaks separated and identified as tri- and tetrasulfide may be ascribed to polysulfides.     

Determination of elemental sulfur by size-exclusion chromatography optimization and petrochemical applications

Factors affecting the elution of elemental sulfur beyond the total permeation limit of a size-exclusion chromatographic (SEC) column are investigated. The pore diameter of the column packing is found to be the most important parameter, and optimum results are achieved from a single 10³ Å pore polystyrene-divinylbenzene column with tetrahydrofuran as solvent. It is shown that both the column temperature and solvent flow-rate have little or no influence on the resolution of sulfur from other sample components. The apparent anomalous elution behavior of sulfur is validated by two independent approaches, and is addressed in terms of electronic interactions between sulfur and the phenyl ring of the polystyrene-divinylbenzene packing. The solubilities of sulfur in typical alkylate, naphtha and reformate samples at room temperature have been determined by the SEC method. The amounts of sulfur in typical hydrotreated cracked naphtha and gas oil samples from pilot unit runs have also been measured. These results are discussed in relation to relative solubilities of sulfur in compounds belonging to different hydrocarbon classes. Specifically, the solubility of sulfur is found to decrease with hydrocarbon type in the order, aromatics>naphthenes>olefins>n-alkanes>isoalkanes.     

Electrochemical performance of sulfur composite cathode materials for rechargeable lithium batteries

The structure and characteristic of carbon materials have a direct influence on the electrochemical performance of sulfur-carbon composite electrode materials for lithium-sulfur battery.In this paper,sulfur composite has been synthesized by heating a mixture of elemental sulfur and activated carbon,which is characterized as high specific surface area and microporous structure.The composite,contained 70%sulfur,as cathode in a lithium cell based on organic liquid electrolyte was tested at room temperature....