一种低共熔溶剂在深度萃取模拟油脱硫中的应用

以咪唑及其衍生物和Bu4NBr为原料,按不同原料配比,通过低温共熔得到了一系列新型低共熔溶剂(DESs),用于萃取脱除模拟油品中的二苯并噻吩(DBT),并对其最佳脱硫条件进行了考察。结果表明:当n(Bu4NBr)/n(咪唑)=0.6时,该类DESs对二苯并噻吩表现出最佳萃取效果。针对DESs考察了剂油体积比与反应温度对脱硫效果的影响,测定了DESs的选择性能与重复使用性能。结果表明:在V(DES)∶V(Oil)=1∶6、萃取温度为20℃、萃取时间为30 min时,咪唑与Bu4NBr共熔物(DESⅠ)对二苯并噻吩的脱硫率达到89.2%;经4次萃取后,其脱硫率达到95.0%;相同条件下该类DESs对于不同噻吩类衍生物的脱除能力的顺序为:二苯并噻吩(DBT)苯并噻吩(BT)4,6-二甲基二苯并噻吩(4,6-DMDBT)噻吩(T);再生后脱硫效果良好;经7次重复萃取过程后,DESs对DBT的脱硫率仍高达86.8%。     

超声条件下柴油氧化脱硫的研究

采用H2O2-甲酸作为氧化剂将催化裂化柴油中的硫化物（主要为苯并噻吩类）氧化成相应的砜,同时引入超声波为反应提供能量,考察（油/剂）比、氧化温度、反应时间、萃取静置时间、（萃取剂/油）比和萃取次数等因素对脱硫效果的影响。在适宜条件下,脱硫率可达94.2%,收率可达90%以上。     

钨酸锰催化氧化脱除模拟油硫化物

通过直接沉淀法制备钨酸锰,采用高温煅烧和双氧水活化的钨酸锰为催化剂,过氧化氢为氧化剂,咪唑氟硼酸盐离子液体为萃取剂,氧化脱除模拟油中的二苯并噻吩(DBT)。研究了反应时间、反应温度、催化剂的加入量、氧化剂用量、萃取剂类型、硫化物类型等因素对催化氧化脱硫的影响,同时考察催化剂/萃取剂脱硫体系循环使用性能。结果表明,最优工艺条件为:反应温度为50℃,H2O2加入量为0.3 m L,催化剂为0.03 g,以咪唑氟硼酸盐为萃取剂,反应时间为60 min时,二苯并噻吩的脱除率可达90%。催化剂/离子液体回收重复使用5次,催化活性无明显下降。     

催化裂化汽油氧化-萃取脱硫

采用催化裂化(FCC)汽油氧化-萃取深度脱硫工艺,考察了氧化反应条件、萃取剂的种类、萃取剂中的含水量以及剂油比对萃取脱硫效果的影响,并对氧化-萃取前后硫含量及类型硫进行了分析。结果表明:杂多酸/相转移剂/H2O2催化氧化体系是非常有效的氧化脱硫体系;随着油剂比、萃取剂含水量的增加,汽油的脱硫率下降,收率增加,在剂油比1∶1、溶剂的含水量10%条件下,汽油的脱硫率达到80%以上,收率97.5%以上;杂多酸/相转移剂/H2O2催化氧化体系对噻吩环被破坏电子效应强的苯并噻吩及甲基苯并噻吩类硫化合物有很好的反应活性,对电子效应弱的噻吩类硫化合物反应活性较低。     

功能化离子液体在燃油脱硫中的研究与应用进展

随着燃油的广泛使用，其中的硫化物对环境产生了不利影响。传统的燃油脱硫方法虽然简便，但是难以脱除芳香类硫化物。离子液体作为新型的绿色溶剂，在燃油脱硫方面表现出了良好的效果和应用潜力。在文献调研的基础上，对功能化离子液体在燃油脱硫中的研究和应用情况进行了总结、分析和讨论。结果表明，通过分子结构的功能化设计和调节，进一步提高了离子液体的萃取和催化性能。一些功能化离子液体对苯并噻吩、二苯并噻吩等硫化物的脱除率可接近甚至达到100%。功能化基团能够增强离子液体与硫化物的相互作用，这是产生较高脱硫效率的重要原因之一。     

高效脱除C9油品中硫化物的研究

利用超声空化原理.以过氧化氢作为氧化剂,在有机和无机复合酸共同催化作用下,将C9油品中的硫化物转化为极性更高的砜或者亚砜,然后采用复合萃取剂将其脱除.该方法中使用的催化剂和萃取剂易于进行回收并再生.最佳的条件是:60°C、剂油体积比1:2,磷酸和甲酸复配催化剂、反应时间20min;采用甲醇与水复合萃取剂(体积比4:1)、萃取剂油比为2:1,萃取2次,此时C9油品的脱硫率可达62.7%,收率80.6%.     

[EMIM]Br-FeCl2离子液体萃取脱除含硫化合物

考察了1-乙基-3-甲基咪唑溴络合氯化亚铁([EMIM]Br-FeCl2)离子液体对含有噻吩(TS)、苯并噻吩(BT)和二苯并噻吩(DBT)模拟油及FCC汽油的萃取脱硫效果。实验结果表明:在40℃条件下萃取4 h,当剂油质量比为2∶1时,噻吩的脱除率为25.6%;当剂油质量比为2∶5时,苯并噻吩的脱除率达到72.4%,二苯并噻吩的脱除率达到79.9%。按剂油质量比2∶1应用于实际汽油,单级萃取脱硫率为50.3%～54.5%,5级萃取脱硫率为89.3%～91.3%。对使用过的离子液体进行再生处理,再生后离子液体可以使用10次以上。     

[Cnmim]Br/FeCl3型离子液体萃取脱除二苯并噻吩

合成了6种咪唑型离子液体[C_3-8mim]Br/FeCl₃,采用红外光谱和拉曼光谱对其进行表征,并考察了离子液体对二苯并噻吩的萃取脱除效果。结果发现,[C₃mim]Br/FeCl₃的萃取脱硫效果最佳,升高温度和增大剂油比均有利于脱硫率的提高,剂油比1:1(体积比)时,萃取时间达到12 min就可使脱硫率高达92%。且萃取反应完成后,离子液体不做处理继续重复使用,重复使用5次,脱硫率可以达到60%。     

MoO3/MIL-101(Cr)负载型催化剂的制备及其氧化脱硫性能

通过煅烧法将钼酸铵和MIL-101的混合物,制备了不同质量分数MoO_3的MoO_3/MIL-101催化剂,采用XRD,FT-IR,SEM,EDS,BET等技术对催化剂的结构和形貌进行表征。以MoO_3/MIL-101为催化剂,乙腈作为萃取剂,H_2O_2为氧化剂氧化脱除模拟油中的二苯并噻吩(DBT)。考察了氧化钼的负载量、反应温度、氧硫比(O/S)、催化剂的用量和乙腈的用量以及不同硫化物对脱硫效果的影响。在最佳的反应条件下,催化剂对DBT,4,6-二甲基苯并噻吩(4,6-DMDBT),苯并噻吩(BT)的脱除率分别达到99%,84%和61.8%。催化剂循环使用4次后活性没有明显下降,并对氧化脱硫反应机理进行了探讨。     

萃取蒸馏脱除油品中硫的过程模拟与优化

汽车尾气严重污染环境,为了生产满足环保法规的硫含量低于10μg/g的汽油,提出了在传统的萃取蒸馏中以有机溶剂+离子液体（IL）为复合萃取剂的脱硫法。以与真实催化裂化（FCC）汽油组成及物性相近的模型油为模拟汽油,利用COSMO-RS模型计算了30种常见IL对环己烷-噻吩的选择性和溶解能力,筛选出用于萃取蒸馏脱硫添加剂的最佳离子液体为[EMIM][BF₄]。通过Aspen Plus软件以N-甲酰吗啉（NFM）+[EMIM][BF₄]为复合萃取剂进行了汽油脱硫的工艺流程模拟与优化。优化结果为萃取剂由NFM（质量分数98%）和[EMIM][BF₄]（质量分数2%）构成,萃取蒸馏塔质量回流比R=0.4,剂油质量比S/F=1,采出率为70%。模拟结果表明：萃取蒸馏可高效地脱除苯并噻吩、硫醚及噻吩类硫化物,上述硫化物总量可从1581μg/g降低至5.37μg/g,脱硫率达98.1%,质量收率为70%,体积收率为75%。此外,通过对比计算值与文献中实验值,验证了COSMO-RS预测IL热力学性质、UNIFAC预测有机硫化物-烃类汽液相平衡的准确性和模拟工艺流程的可靠性。     

Deep oxidative–extractive desulfurization of fuels using benzyl‐based ionic liquid

Four benzyl‐based ionic liquids (ILs) were synthetized and used for deep desulfurization of model oil and real diesel fuel. The removal efficiencies of benzothiophene (BT) and dibenzothiophene (DBT) with [Bzmim][NTf₂] and [Bzmim][SCN] as extractants are higher than that with [Bzmp][NTf₂] and [Bzmp][SCN] as extractants. The desulfurization capability follows the Nernst's Law. A reactive extraction mathematical model for desulfurization was established. An oxidative‐extractive two‐step deep desulfurization method was developed. DBT was first oxidized by H₂O₂ with CH₃COOH as catalyst and then the unoxidized DBT and uncrystallized dibenzothiophene sulfoxide (DBTO₂) in model oil were extracted by [Bzmim][NTf₂], and finally the removal efficiency was 98.4% after one‐stage extraction. Besides, the removal efficiency of 4,6‐DMDBT was 96.4% after oxidation and one‐stage extraction processes. Moreover, the oxidative‐extractive two‐step deep desulfurization method was also effective for desulfurization of diesel fuel. The removal efficiency of sulfur reached up to 96% after oxidation and three‐stage cross‐current extraction processes. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4023–4034, 2016     

低共熔溶剂在车用燃料脱硫中的研究进展

低共熔溶剂作为近十年来迅速发展的一类新型绿色溶剂,不仅具备离子液体的优点,而且原料价廉易得、合成条件简单、萃取脱硫效果好,已成为继离子液体用于车用燃料脱硫研究之后又一新的研究热点。本文根据合成低共熔溶剂的盐与氢键供体（或水合盐）的不同,对用于车用燃料脱硫的低共熔溶剂进行了分类总结,简述了低共熔溶剂的物化性质,介绍了低共熔溶剂用于车用燃料脱硫的方法及研究进展,对比了低共熔溶剂对不同含硫化合物的脱除效果,归纳了低共熔溶剂的萃取脱硫和氧化萃取脱硫机理。最后针对低共熔溶剂用于车用燃料脱硫中存在的选择性低、循环再生等关键问题,指出了其研究发展方向应是通过开发具有萃取脱硫高选择性的低共熔溶剂以及寻找新型绿色环保的低共熔溶剂脱硫方法来实现深度脱硫。     

Removal of Dibenzothiophene from Diesels by Extraction and Catalytic Oxidation with Acetamide‐Based Deep Eutectic Solvents

A series of acetamide‐based deep eutectic solvents (DESs) with different proportions were prepared. Extraction and catalytic oxidation desulfurization (ECODS) of the acetamide‐based DESs were investigated and the process was optimized. Such DESs with a molar ratio of acetamide and p‐TsOH of 1/3 (C₂H₅NO/3p‐TsOH) exhibits such a remarkable catalytic activity that the dibenzothiophene (DBT) removal could reach 100 % under optimized conditions. C₂H₅NO/3p‐TsOH was used for the oxidative desulfurization of actual commercial diesel. The sulfur removal of diesel achieved up to 98 %. C₂H₅NO/3p‐TsOH could be recycled six times and the desulfurization activity was slightly decreased. Evaluation of the mechanism indicated that oxidative desulfurization (ODS) was realized via dual activation of acetamide‐based DESs. A novel and effective way for deep desulfurization of diesel is provided.     

Extractive Desulfurization of Fuel Oils with Thiazolium-Based Ionic Liquids

A new class of green solvents, known as ionic liquids (ILs), has recently been the subject of intensive research on the extractive desulfurization of fuel oils because of the limitation of the traditional hydrodesulfurization method in catalytically removing thiophenic sulfur compounds. In this work, four thiazolium-based ILs, that is, 3-butyl-4-methylthiazolium dicyanamide ([BMTH][DCA]), 3-butyl-4-methylthiazolium thiocyanate ([BMTH][SCN]), 3-butyl-4-methylthiazolium hexafluorophosphate ([BMTH][PF₆]), and 3-butyl-4-methylthiazolium tetrafluoroborate ([BMTH][BF₄]), are synthesized. The extractive capability of these ILs in removing thiophene (TS) and dibenzothiophene (DBT) from model fuel oils is investigated. [BMTH][DCA] and [BMTH][SCN] present better extractive desulfurization capability than [BMTH][BF₄] and [BMTH][PF₆], which may be ascribed to the additional π?π interaction between –C≡N (in [BMTH][DCA] and [BMTH][SCN]) and thiophenic ring (in TS and DBT); DBT in diesel fuel is more efficiently extracted than TS in gasoline. [BMTH][DCA] offers the best desulfurization results, where 64% and 45% sulfur removal are obtained for DBT and TS, respectively, at IL:oil mass ratio of 1:1, 25°C, 20 min. [BMTH][DCA] is thus selected to systematically investigate the effects of temperature, IL:oil mass ratio, initial sulfur content, multiple-extraction, and IL regeneration on desulfurization. The mutual solubility of [BMTH][DCA] with fuel oil is also determined. It is observed that the desulfurization capability is not too sensitive to temperature and initial sulfur content, which is desired in industrial application; the sulfur contents in gasoline and diesel fuel are reduced from 558 ppm to 20 ppm (after 5 cycles) and from 547 ppm to 8 ppm (after 4 cycles), respectively. This work may show a new option for deep desulfurization of fuel oils.     

Deep desulfurization of diesel via peroxide oxidation using phosphotungstic acid as phase transfer catalyst

High sulfur level in diesel fuel has been identified as a major contributor to air pollutant in term of sulfur dioxide (SO_x) through diesel fueled vehicles. The main aim of the present work is to develop a promising methodology for ultra deep desulfurization of diesel fuel using oxidation followed by phase transfer of oxidized sulfur. Experiments were carried out in a batch reactor using n-decane as the model diesel compound and also using commercial diesel feedstock. To remove sulfur tetraoctylammonium bromide, phosphotungstic acid, and hydrogen peroxide were used as phase transfer agent, catalyst and oxidant respectively. The percent sulfur removal increases with increasing the initial concentration of sulfur in fuel and with increasing the reaction temperature. Similar trends were observed when commercial diesel was used to carry out desulfurization studies. The amphiphilic catalyst serves as a catalyst and also as an emulsifying agent to stabilize the emulsion droplets. The effects of temperature, agitation speed, quantity of catalyst and the phase transfer agent were studied to estimate the optimal conditions for the reactions. The sulfur removal from a commercial diesel by phase transfer catalysis has been found effective and removal efficiency was more than 98%. Kinetic experiments carried out for the desulfurization revealed that the sulfur removal results are best fitted to a pseudo first order kinetics and the apparent activation energy of desulfurization was 30.6 kJ/mol.     

A new method for obtaining ultra-low sulfur diesel fuel via ultrasound assisted oxidative desulfurization☆

Due to the requirement of stringent rules for ultra-low sulfur content of diesel fuels, it is necessary to develop alternative methods for desulfurization of fossil fuel derived oil. Using appropriate oxidants and catalysts with the assistance of ultrasound irradiation, model compounds such as dibenzothiophene can be quantitatively oxidized in minutes. For diesel fuels containing various levels of sulfur content, and through the use of catalytic oxidation and ultrasonication followed by solvent extraction, removal efficiency of sulfur-bearing compounds can reach or exceed 99% in a short contact time at ambient temperature and atmospheric pressure. This simple approach can be the basis for obtaining ultra-low sulfur-containing diesel oil. GC-PFPD, GC-MS, and GC-SIMDIS were used to monitor the change of organic sulfur compounds and hydrocarbons in diesels during the process.     

燃油深度脱硫研究进展

随着国际燃油标准的不断提高,燃油低硫化的需求日益增长。氧化和吸附脱硫与加氢脱硫相比,能够节约投资和操作成本50%左右。对近年来这两种脱硫方法的科研成果进行了论述,主要涉及脱硫机理,氧化剂或吸附剂的制备及脱硫效果。催化氧化脱硫能脱除苯并噻吩和二苯并噻吩类化合物,难于脱除噻吩类化合物;吸附脱硫则因吸附剂的不同,含硫化合物的脱除顺序有所不同。基于这两种脱硫方法的不同特点,进一步提出了燃油深度脱硫的可行性方案。     

Deep Desulfurization of Gasoline Fuel using FeCl3-Containing Lewis-Acidic Ionic Liquids

The FeCl₃-containing Lewis-acidic ionic liquids (ILs) [C₆mim]Cl/FeCl₃(1:1.5), [C₆mim]Cl/FeCl₃(1:2), [C₈mim]Cl/FeCl₃(1:1.5), and [C₈mim]Cl/FeCl₃(1:2) were used as extractants for desulfurization of model fuel and gasoline fuel, respectively. The results demonstrate that these ILs are effective for the removal of sulfur compounds from model fuel under different mass ratio of IL to model fuel (1:1, 1:3, 1:5, 1:10) at 25°C. The extractive performance of ILs increased as the molar ratio of FeCl₃ to [C_nmim]Cl(n = 6, 8) varied from 1:1 to 1:2. The selectivity of sulfur compounds by extraction process followed the order of dibenzothiophene (DBT)>benzothiophene (BT) > 4,6-dimethyldibenzothiophene (4,6-DMDBT). The sulfur removal of gasoline fuel containing sulfur content of 440.3 ppmw could be up to 85.8%; that is to say that the sulfur content of gasoline fuel varied from 440.3 ppmw to 62.4 ppmw after one extraction stage. Moreover, the [C₆mim]Cl/FeCl₃(1:2) can be recycled for at least 4 times with a little decrease in the desulfurization activity.     

Trihexyl(tetradecyl)phosphonium hexafluorophosphate as an promising Extractant for extractive desulfurization from liquid fuels

Experimental data on extractive desulfurization (EDS) of dibenzothiophene (DBT), thiophene, benzothiophene, and other substituted derivatives of sulfur from liquid fuel using trihexyl(tetradecyl)phosphonium hexafluorophosphate ([THTDP][PF₆]) have been presented. The Fourier transform infrared spectrophotometer, ¹H-NMR, ¹³C-NMR, and ³¹P-NMR analysis have been discussed for molecular confirmation, and conductivity, solubility, and viscosity analyses of ([THTDP][PF₆]) were investigated. The effects of time, temperature, S-compounds, ultrasonication, and recycling of ([THTDP][PF₆]) on DBT removal from fuel were examined. Also, desulfurization of real fuels and multistage extraction was also tested. The data and results provided the significant insights of phosphonium ionic liquids as a promising solvent for EDS.