GC-AED法研究催化裂化柴油中硫氮化合物

采用气相色谱-原子发射光谱（GC-AED）联用技术对FCC柴油中的含硫化合物、含氮化合物进行定性定量研究。结果表明：FCC柴油中硫化物的类型主要是噻吩类衍生物、苯并噻吩、苯并噻吩类衍生物、二苯并噻吩、二苯并噻吩类衍生物,其中苯并噻吩类衍生物、二苯并噻吩类衍生物的硫质量分数占总硫质量分数的93．6％以上。氮化物主要为碱性氮化物（Nb）和非碱性氮化物（Np）两大类型,其中碱性氮化物主要是苯胺及其衍生物,喹啉含量很低,约占总氮质量分数的0．1％,非碱性氮化物主要包括吲哚及其衍生物和咔唑及其衍生物,而咔唑类氮化物一般约占总氮质量分数的64％。不同来源的FCC柴油,其所含硫化物、氮化物的含量和分布不同。应根据其硫化物、氮化物的分布类型及规律,开发合适的柴油脱硫脱氮催化剂及相关工艺。     

柴油深度脱硫技术研究进展

加氢柴油中残留的硫化物主要为二苯并噻吩及其衍生物,因此,脱除柴油中二苯并噻吩类硫化物是实现柴油深度脱硫的关键技术。系统地介绍了加氢脱硫、生物脱硫、氧化脱硫和吸附脱硫等技术及其优缺点,重点介绍了反应吸附脱硫技术的最新研究进展。     

Ni离子改性分子筛模拟柴油吸附脱硫的性能与机理

研究镍改性分子筛吸附剂在模拟柴油中脱除苯并噻吩类硫化物的性能.实验表明:采用液相离子交换法是优选的分子筛改性方法,过渡金属Ni离子改性的Ni-Y吸附剂具有较佳的脱硫性能,室温(20℃)下采用静态吸附法测得的静态吸附平衡硫容量为17.16 mg S·(g吸附剂)-1;采用固定床动态吸附,测得每克吸附剂饱和硫容量达到33.6 mg S·(g吸附剂)-1,并能将初始硫含量为840×10-4%(wt)的模拟柴油处理至硫含量低于5×10-4%(wt).实验还发现,吸附剂对模拟柴油中二苯并噻吩的脱除能力优于苯并噻吩,吸附剂的硫容量与金属离子交换率成正比.由金属离子交换和不同孔径的分子筛吸附实验研究结果可以推断,吸附剂的吸附脱硫是分子尺寸选择机理和(配位机理共同作用的结果.     

稀土元素Ce对硫化物在Cu~+-13X上动态竞争吸附的影响

采用液相离子交换法制备了Cu+-13X及负载稀土元素Ce的Ce/Cu+-13X分子筛吸附剂。采用固定床动态吸附实验考察了Ce/Cu+-13X对2,5-二甲基噻吩、苯并噻吩动态吸附性能。研究结果表明,稀土元素Ce的引入可以促进Cu+-13X对2,5-二甲基噻吩和苯并噻吩的吸附性能,同时减弱竞争吸附。在床层高度为16 cm、进样速度为16 mL/h、停留时间为30 min时,效果最佳。     

高硫柴油吸附脱硫剂的研究

研究了不同的Cu2+分子筛在常温常压下吸附高硫柴油中的硫化合物。采用水热合成法和离子交换法制备含Cu2+分子筛(CuMCM41和CuZSM5),用于固定床吸附脱硫。其中每克CuMCM41处理5 mL高硫柴油后达到饱和,并且能把含硫量降到300×10-6(质量分数)。吸附剂对硫化物具有很强的选择性,用CuMCM41来吸附模拟柴油,吸附结果表明它对噻吩和苯并噻吩的吸附性比对萘要强。     

改性NaY分子筛吸附脱硫性能的研究

以NaY分子筛为载体,采用液相离子交换法制备了一系列用于燃料油脱硫的负载金属离子的改性分子筛吸附剂.结果表明,AgY具有最高的硫容,其次是CuY、NiY、CeY、ZnY,硫化物吸附量顺序为:噻吩＞苯并噻吩＞二苯并噻吩.通过正交实验优化了Y分子筛的制备工艺,并对实验数据进行了方差分析,得到了最佳制备工艺条件:活性组分为A...     

吸附法柴油脱硫技术进展

本文从吸附剂改性、吸附脱硫机理和吸附剂再生等方面综述了以活性炭、金属氧化物、分子筛等为吸附材料吸附脱除柴油中硫化物的最新进展。柴油中的含硫化合物主要包括无机硫和有机硫,其中有机硫占80％以上。在活性炭表面,金属氧化物或分子筛上负载过渡金属都可提高其对硫的吸附能力,π键配位吸附脱硫技术是脱除噻吩类硫化物的有效方法。吸附脱硫是一项具有发展潜力的脱硫技术,然而,要加速这一技术的工业化进程,开发对稠环噻吩类硫化物具有高选择性、高吸附量、易再生的吸附剂是当前面临的重要挑战。     

负载金属离子ZSM-5分子筛膜脱除苯并噻吩-二苯并噻吩的性能

采用水热合成法制备ZSM-5分子筛膜,并通过负载金属离子对其进行改性。通过X线衍射仪(XRD)、扫描电子显微镜(SEM)对所制备的膜进行表征。将所制得的ZSM-5分子筛膜经过负载金属离子改性后用于模拟汽油中苯并噻吩、二苯并噻吩二元硫化物的分离,考察负载离子种类、负载离子浓度和操作温度对二元硫化物竞争吸附和渗透通量的影响,并应用软硬酸碱理论(HSAB)分析吸附能力的强弱。结果表明:当Ag+浓度为0.2 mol/L时硫化物的分离因子最高可达1.31;随着操作温度的升高,ZSM-5分子筛膜渗透通量逐渐增大而分离因子逐渐减小。     

吸附法脱除柴油中噻吩类含硫化合物的研究进展

综述了吸附法脱除柴油中噻吩类含硫化合物的常用吸附剂、吸附脱硫的机理及吸附脱硫过程动力学研究的最新进展。阐述了近来研究较多的吸附剂主要有分子筛、活性炭和金属有机骨架（MOFs）材料。目前传统的加氢脱硫（HDS）技术虽然可以满足当前柴油中硫含量的国家标准,但是其需要高温高压、成本高且对二苯并噻吩类硫化物脱硫率低,而吸附脱硫技术由于成本低、操作条件温和、易脱除加氢脱硫难以脱除的硫化物、对油品品质影响小等优点成为当前柴油脱硫的研究热点。吸附脱硫主要包括反应型吸附脱硫和非反应型吸附脱硫,反应吸附脱硫关键是有旧键的断裂与新键的生成,而非反应吸附脱硫则是通过分散力使硫化物上的硫原子与吸附剂之间相互作用,从而达到吸附脱硫的作用。本文对吸附脱硫机理和吸附脱硫过程的动力学加以讨论,为以后的研究提供一定的理论基础,并提出了脱硫吸附剂今后的研究方向。     

过渡金属离子改性Na-13X分子筛对噻吩类硫化物的吸附性能与机理

采用液相离子交换法制备Cu+-13X、Ni2+-13X和Co2+-13X吸附剂,利用XRD、FT-IR和Laser-raman等对其进行表征。在常温常压条件下,以含有噻吩、2-乙基噻吩和苯并噻吩的正己烷溶液为模拟汽油,通过静态吸附实验与动力学吸附实验研究了3种吸附剂对噻吩、2-乙基噻吩和苯并噻吩的吸附性能与机理,并采用Langmuir模型对静态吸附平衡数据进行拟合和Crank单孔扩散模型对动力学吸附数据进行拟合。实验结果表明过渡金属离子改性的分子筛对噻吩类硫化物有较高的吸附含量;改性后分子筛的选择吸附性能取决于吸附质与吸附剂之间的π络合作用和吸附剂的表面酸性,而受硫化物的空间位阻影响作用很小。     

Investigation of the enhancing effects of sulfur and/or oxygen functional groups of nanoporous carbons on adsorption of dibenzothiophenes

Adsorption of dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (DMDBT) from simulated diesel fuel with 20 ppmw total concentration of sulfur was investigated on polymer-derived carbon containing various amounts of oxygen and sulfur incorporated to the surface. Initial and exhausted carbons were characterized using adsorption of nitrogen, thermal analysis, potentiometric titration, XPS, mass spectroscopy and elemental analysis. Selectivities for DBT and DMDBT adsorption were calculated with reference to naphthalene. It was found that both the capacity and selectivity for DBT and DMDBT removal from model diesel fuel were affected by the content and arrangement of heteroatoms. Although both oxygen and sulfur containing groups enhance the capacity, the enhancing effects of surface chemistry were more pronounced on the carbon with sulfur incorporated to its matrix. This is linked to sulfur–sulfur interactions.     

Diesel fuel desulfurization with hydrogen peroxide promoted by formic acid and catalyzed by activated carbon

Desulfurization of diesel fuels with hydrogen peroxide was studied using activated carbons as the catalysts. Adsorption and catalytic properties of activated carbons for dibenzothiophene (DBT) were investigated. The higher the adsorption capacity of the carbons is, the better the catalytic performance in the oxidation of DBT is. The effect of aqueous pH on the catalytic activities of the activated carbons was also investigated. Oxidation of DBT is enhanced when the aqueous pH is less than 2, and addition of formic acid can promote the oxidation. The effect of carbon surface chemistry on DBT adsorption and catalytic activity was also investigated. Adsorption of DBT shows a strong dependence on carboxylic group content. The oxidative removal of DBT increases as the surface carbonyl group content increases. Oxidative desulfurization of a commercial diesel fuel (sulfur content, 800 wt. ppm) with hydrogen peroxide was investigated in the presence of activated carbon and formic acid. Much lower residual sulfur content (142 wt. ppm) was found in the oxidized oil after the oxidation by using the hydrogen peroxide-activated carbon-formic acid system, compared with a hydrogen peroxide-formic acid system. The resulting oil contained 16 wt. ppm of sulfur after activated carbon adsorption without any negative effects in the fuel quality, and 98% of sulfur could be removed from the diesel oil with 96.5% of oil recovery. Activated carbon has high catalytic activity and can be repeatedly used following simple water washing, with little change in catalytic performance after three regeneration cycles.     

Influence of fuel sulfur on the characterization of PM10 from a diesel engine

To study the effects of fuel sulfur content on the characteristics of diesel particle emitted from a typical engine used in China, two types of diesel fuel with sulfur content of 30 ppm and 500 ppm were used in this engine dynamometer test under six operation conditions corresponding to 20%, 50% and 80% load at 1400 rpm and 2300 rpm engine speeds, respectively. Gaseous pollutants and particulate matter (PM) emissions were sampled with AVL AMA4000 and Model 130 High-Flow Impactor (MSP Corp), respectively. More specifically, the PM mass, total carbon (TC), organic carbon (OC), elemental carbon (EC) and water-soluble ion distribution were also measured. Compared with high sulfur diesel, the application of low sulfur diesel can lower fuel-based PM emissions by 9.2-56.6%. At 1400 rpm, the low sulfur diesel decreased both OC and EC by 5-34% and about 20%; while at 2300 rpm, the low sulfur fuel decreased OC by 33-57% and increased EC emission, resulting in a lower OC/EC ratio. The evidence implicating that OC oxidation was promoted by low sulfur diesel, but the effect on EC oxidation was dependent on engine speed. The linear regression has been conducted between TC and PM₁₀, and the slopes were 0.88 and 0.80 for low sulfur diesel and high sulfur one, respectively. Higher sulfate content was detected in the 0.13 μm particles when using the high sulfur diesel, but the percentage of sulfate was 0.9% for PM₁₀ from both diesel fuels. Comparing with that of 500 ppm, EC increased sharply to a maximum of 114% in particles of 0.13 μm when using 30 ppm sulfur diesel at 2300 rpm.     

基于阻滞扩散模型估算柴油脱硫吸附剂的适宜孔径分布

通过GC-PFPD色谱分析国Ⅱ、国Ⅲ、国Ⅳ标准0^#柴油中的主要含硫组分,发现苯并噻吩(BT)、二苯并噻吩(DBT)及其烷基取代衍生物是0^#柴油中的主要含硫化合物,C₂-DBT、C₃-DBT是国Ⅳ柴油中的主要含硫化合物。以BT、DBT、4,6-DMDBT为模型化合物,计算含硫化合物在不同大小孔道内的扩散阻滞因子,结合氧化铝堆积孔模型,估算氧化铝基柴油脱硫吸附剂的适宜孔径分布。结果表明,当氧化铝的平均孔径为4～10 nm时,含硫化合物的扩散阻滞因子为0.24～0.65,氧化铝的比表面积为100～250 m²·g^-1,可同时满足较低的扩散阻力和足够大的比表面积。对比分析不同氧化铝的孔分布及其吸附脱硫性能,结果表明氧化铝中4～10 nm范围内的孔面积占总孔面积的百分比与其吸附脱硫性能存在显著的正相关关系,初步推测氧化铝基脱硫吸附剂的适宜孔径分布范围为4～10 nm。     

Design and analysis of a diesel processing unit for a molten carbonate fuel cell for auxiliary power unit applications

Fuel cell-based auxiliary power units (APUs) are a promising technology for meeting global energy needs in an environmentally friendly way. This study uses diesel containing sulfur components such as dibenzothiophene (DBT) as a feed. The sulfur tolerance of molten carbonate fuel cell (MCFC) modules is not more than 0.5 ppm, as sulfur can poison the fuel cell and degrade the performance of the fuel cell module. The raw diesel feed in this study contains 10 ppm DBT, and its sulfur concentration should be reduced to 0.1 ppm. After desulfurization, the feed goes through several unit operations, including steam reforming, water-gas shift, and gas purification. Finally, hydrogen is fed to the fuel cell module, where it generates 500 kW of electrical energy. The entire process, with 52% and 89% fuel cell and overall system efficiencies, respectively, is rigorously simulated using Aspen HYSYS, and the results are input into a techno-economic analysis to calculate the minimum electricity selling price (MESP). The electricity cost for this MCFC-based APU was calculated as 1.57$/kWh. According to predictions, the cost reductions for fuel cell stacks will afford electricity selling prices of 1.51$/kWh in 2020 and 1.495$/kWh in 2030. Based on a sensitivity analysis, the diesel price and capital cost were found to have the strongest impact on the MESP.     

PY-GC法研究渣油中硫化物的热裂解性能

采用裂解气相色谱（PY-GC）方法研究渣油中的大分子硫化物的裂解性能。首先对（PY-GC）的实验条件进行优化,在此基础上,得到了可以反应渣油样品中硫化物组成和结构的裂解色谱图;通过标准物对比并结合文献对渣油裂解产物中硫化物的组成进行定性。研究发现,渣油高温裂解产物中的硫化物主要有：H2S、噻吩类、苯并噻吩类和二苯并噻吩类系列的化合物。根据模型化合物的裂解色谱分析结果,推测出渣油裂解产物中的H2S不仅来源于重油分子中硫醚类结构的裂解,而且与重油分子中噻吩、苯并噻吩和二苯并噻吩类结构的裂解有关,而渣油裂解产物中的噻吩、BT和DBT系列化合物主要来自于重油中的大分子噻吩、BT和DBT类化合物的裂解。     

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     

模仿离子液银盐法进行脱硫工艺的研究

油品中含硫化合物所产生的危害是多方面的,特别是近年来车用燃料尾气排放的二氧化硫对环境造成的负面影响更引起了人们的关注。发达国家纷纷制定环保法规严格限制油品中硫的质量分数,因此,讨论各种脱硫技术对我国炼油工业具有重要意义。对一种新的脱硫方法进行了考察。将235～270℃之间的煤油馏份进行预先精制,向其中加入一定量的苯并噻吩、二苯并噻吩作为原料,在氮气保护条件下进行烷基化脱硫工艺的研究。实验结果表明：在反应温度为30℃,CH3CH2Br：S=30：1（mol／mol）,AgBF4：S=6：1（mol／mol）,反应时间为16h的条件下,脱硫率可以达到76．3％。     

Oxidative desulfurization of model and real oil samples using Mo supported on hierarchical alumina-silica: Process optimization by Box-Behnken experimental design

The catalytic performance of Mo supported on hierarchical alumina-silica (Si/Al=15) with Mo loadings of 3, 6 and 15 wt% was investigated for the oxidative desulfurization (ODS) of model and real oil samples. Hierarchical alumina-silica (hAl-Si) was synthesized by economical and ecofriendly silicate-1 seed-induced route using cetyltrimethylammonium bromide (CTAB) as mesoporogen. The effect of CTAB on the structure of catalyst was studied by characterization techniques. The results revealed that 6%Mo/hAl-Si had the highest sulfur removal compared to the other catalyst loadings. The effect of operating parameters was evaluated using Box-Behnken experimental design. The optimal desulfurization conditions with the 6%Mo/hAl-Si catalyst were determined at oxidation temperature of 67℃, oxidation time of 42 min, H₂O₂/S molar ratio of 8 and catalyst dosage of 0.008 g·ml^-1 for achieving a conversion of 95%. Under optimal conditions, different sulfur-containing compounds with initial concentration of 1000 ppm, Dibenzothiophene (DBT), Benzothiophene (BT) and Thiophen (Th), showed the catalytic oxidation reactivity in the order of DBT > BT > Th. According to the regeneration experiments, the 6%Mo/hAl-Si catalyst was reused 4 times with a little reduction in the performance. Also, the total sulfur content of gasoline and diesel after ODS process reached 156.6 and 4592.2 ppm, respectively.     

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.