The Deep Oxidative Desulfurization of Fuels Using Na2WO4.2H2O in Acidic Ionic Liquids

The catalytic oxidation desulfurization system is composed of Na₂WO₄.2H₂O, H₂O₂, acidic ionic liquid, and phase transfer catalyst has been found suitable for deep removal of organic sulfur in fuels. Under the optimal conditions, the desulfurization efficiency is virtually 100%. Moreover, this acidic ionic liquid can be recycled five times without obviously decrease in activity. Meanwhile, the mechanism of oxidation desulfurization was also elaborated.     

离子液体用于催化裂化汽油烷基化脱硫的实验室研究

将离子液体用于催化裂化汽油烷基化脱硫实验，考察了不同阳离子、阴离子、阴阳离子比例对催化裂化汽油脱硫率的影响。研究结果表明，在离子液体作用下，FCC汽油中噻吩类硫化物与烯烃发生烷基化反应，生成了沸点更高的烷基化产物。由于叔胺盐阳离子在具有Lewis酸性的同时还有Broensted酸性，由它形成的离子液体酸性较强。与CuCl、SnCl2相比，由AlC13提供阴离子合成的离子液体的酸性最强，更适合做烷基化催化剂。由AlCl3与Et3NHCl按摩尔比为2：1合成的离子液体作用于FCC汽油，脱硫率在70％以上，汽油收率在95％以上，辛烷值基本无变化。     

Deep Oxidative Desulfurization of Dibenzothiophene in Simulated Diesel with Tungstate and H2O2 in Ionic Liquids

Abstract

A green extraction and catalytic oxidative desulfurization (ECODS) system composed of simple tungsten-containing catalyst, 30 wt% H₂O₂, and ionic liquids was discovered suitable for the deep removal of dibenzothiophene (DBT) in simulated diesel. In the case of the system comprising Na₂WO₄ · 2H₂O, 30 wt% H₂O₂ and 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim]BF₄), the removal of DBT could reach 99.7% at 60°C for 3 hr, which was superior to mere solvent extraction with ionic liquid or catalytic oxidation without ionic liquid. This desulfurization system could be recycled five times with a small decrease in activity.     

Synthesis of amphiphilic peroxophosphomolybdates for oxidative desulfurization of fuels in ionic liquids

Three amphiphilic peroxophosphomolybdates [C₄mim]₃PMo₄O₂₄, [C₈mim]₃PMo₄O₂₄ and [C₁₆mim]₃PMo₄O₂₄ were synthesized and characterized. These catalysts were used for extraction and catalytic oxidative desulfurization of fuel with H₂O₂ as an oxidant and ionic liquid [C₄mim]BF₄ as an extractant. It was found that [C₁₆mim]₃PMo₄O₂₄ showed the highest catalytic activity and the sulfur content could decrease to 7.5 ppm. In contrast, the desulfurization system shows very low performance without H₂O₂ or ionic liquid. The detailed reaction conditions were optimized including reaction time, temperature, the dosage of H₂O₂ and catalyst, and different sulfur compounds. After the reaction, the catalysts and the ionic liquid can be cycled 8 times with a little decrease in desulfurization efficiency.     

离子液体合成及多级逆流萃取脱硫的串级实验法验证研究

通过两步合成法合成了1-庚基-3-甲基咪唑四氟硼酸盐离子液体（[C7MIM]BF4）,以30%的过氧化氢作氧化剂,考察了其在不同剂油比、萃取时间、萃取温度、萃取速率下对汽油的脱硫效果,确定了最佳脱硫条件,计算出离子液体多级逆流萃取脱硫的理论级数,并在此条件下平行做三组串级实验,进行多级逆流萃取脱硫的模拟验证。结果表明,在V([C7MIM]BF4):V(H2O2):V(Oil)=1:1:10、反应温度60 ℃、震荡速率600 r/min的条件下反应60 min后,一次脱硫率达到77 %,采用四级逆流萃取脱硫后,汽油的硫质量分数由155 μg/g降至10 μg/g以下,脱硫率达到94 %,汽油回收率达到95 %,具有较好的工业应用前景。     

硫磺回收装置停工热氮除硫工艺研究

目的 降低硫磺回收装置停工除硫期间尾气中SO2排放量.方法 对比传统燃料气除硫及热氮除硫工艺的技术特点、原理及优缺点,采用Aspen Plus软件进行模拟计算,并结合热氮除硫工艺的技术特点,对3个阶段的除硫流程进行优化操作.结果 通过对比分析及Aspen Plus软件模拟计算结果可知,热氮除硫技术可降低硫磺回收装置停工...     

Study on a new desulfurization method based on imitating ionic liquids for light diesel oil

A simulated light oil consisting of model sulfur compounds of benzothiophene (BT), dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT) and straight-run light diesel oil fractions as solvent was employed for desulfurization tests imitating silver-salt method for ionic liquids (ILs). Under the conditions of a nitrogen atmosphere, reaction temperature of 303 K, reaction time of 24 h, the effects of different alkylating agents and amount of agent on the sulfur removal were investigated in more details. The results showed that when ratio of bromoethane (CH₃CH₂Br) to sulfur is 80: 1 (mol/mol) and ratio of potassium tetrafluoroborate (KBF₄) to sulfur 30: 1 (mol/mol), the desulfurization yield were 72.6%.     

Polyoxometalate-based silica-supported ionic liquids for heterogeneous oxidative desulfurization in fuels

With the aim of deep desulfurization, silica-supported polyoxometalate-based ionic liquids were successfully prepared by a one-pot hydrothermal process and employed in heterogeneous oxidative desulfurization of various sulfur compounds. The compositions and structures of the hybrid samples were characterized by various methods such as FT-IR, XPS, Raman,UV–Vis, wide-angle XRD and N_2 adsorption–desorption. The experimental results indicated that the hybrid materials presented a high dispersion of tungsten species and excellent catalytic activity for the removal of 4,6-dimethyldibenzothiophene without any organic solvent as extractant, and the sulfur removal could reach 100.0% under mild conditions.The catalytic performance on various substrates was also investigated in detail. After cycling seven cycles, the sulfur removal of the heterogeneous system still reached 93.0%. The GC-MS analysis results demonstrated that the sulfur compound was first adsorbed by the catalyst and subsequently oxidized to its corresponding sulfone.     

Optimization of Oxidative Desulfurization of Dibenzothiophene Using a Coordinated Ionic Liquid as Catalytic Solvent

Abstract

Oxidative desulfurization (ODS) of dibenzothiophene (DBT) in n-octane with hydrogen peroxide/acetic acid using a quaternary ammonium coordinated ionic liquid (IL) (C₄H₉)₄NBr · 2C₆H₁₁NO as catalytic solvent has been studied. The ODS mechanism by coordinated ionic liquid [(C₄H₉)₄NBr · 2C₆H₁₁NO] was also carried out. The sulfur-containing compounds in model oil were extracted into ionic liquid phase and oxidized to their corresponding sulfones by H₂O₂. The effect factors for desulfurization of model oil were investigated in detail by means of monofactorial and orthogonal experiments (L₁₆(4)⁴). The results showed that the desulfurization efficiency of model oil could reach 98.6% under the optimal conditions of oxidation time, oxidation temperature, molar ratio of H₂O₂/sulfur (O/S), and volume ratio of model oil to coordinated ionic liquid were 30 min, 50°C, 16, and 1, respectively. The influences to the desulfurization efficiency of DBT decreased in the following order: volume ratio of model oil to coordinated ionic liquid (C₄H₉)₄NBr · 2C₆H₁₁NO (V_{model oil}/V_IL) > molar ratio of O/S > oxidation temperature > oxidation time, according to extreme analysis of the orthogonal test. The coordinated ionic liquid (C₄H₉)₄NBr · 2C₆H₁₁NO can be recycled 5 times without a significant decrease in desulfurization.     

[bmim]OH和[A336][FeCl_4]混合离子液体氧化吸收硫化氢

为了降低非水相催化氧化硫化氢体系的运行成本,将碱性的氢氧化1-丁基-3-甲基咪唑([bmim]OH)离子液体与价格较低的酸性三辛基甲基铵四氯铁酸盐([A336][FeCl_4])离子液体分别按照0.2∶1、0.5∶1、0.8∶1、1∶1和2∶1的比例混合,用所得到的混合离子液体进行硫化氢氧化吸收实验,系统研究了混合离子液体的水溶性、密度、红外光谱、黏度和酸性强度等性能,并对其硫容和反应产物进行了分析。研究结果表明:(1)[A336]FeCl_4季铵盐离子液体的酸性强度和价格均低于[bmim]Fe Cl4离子液体,可以降低离子液体非水相催化氧化硫化氢体系的成本;(2)混合离子液体不仅同时具有[bmim]OH和[A336][FeCl_4]的骨架结构,且其p H值、黏度和硫容均随[bmim]OH量的增加而增加;(3)混合离子液体明显弱于[A336][FeCl_4]离子液体的酸性强度,有利于硫化氢的吸收,其黏度随温度上升而剧烈下降的性质有利于中、高温脱硫。结论认为,当[bmim]OH/[A336][FeCl_4]的物质的量之比在0.5∶1~1∶1时,可以构建成本较低、酸性适中、黏度较低、硫容较高的中、高温脱硫体系。     

含硫气井络合铁脱硫工艺技术及经济适应性研究

目的确定含硫气井采用络合铁脱硫工艺进行脱硫净化的技术及经济适应性。 方法分析了络合铁脱硫工艺的原理、流程及特点,根据含硫气井工业应用实例,研究提出了络合铁脱硫工艺的技术及经济适应性条件。 结果在技术性方面,络合铁脱硫工艺适用于任何H₂S含量的天然气脱硫,H₂S脱除率可达到99.9%以上,且脱除效果稳定,短期内不受H₂S含量波动的影响;CO₂脱除率由吸收塔运行压力及原料气中CO₂含量决定;对不同含量的甲硫醇、乙硫醇脱除率可分别达到97%、92%以上,对羰基硫的脱除率约为6.51%~35.02%;合理硫容应为药剂及电耗综合成本最低时的硫容,不同的运行工况,合理硫容也不同;工艺产生的单质硫目前主要以硫膏形式脱除及处理,对硫磺进行经济、环保的回收处理是络合铁脱硫工艺的一个难点。在经济性方面,开展了工艺完全成本分析,提出了在潜硫量为12.35 t/d的条件下工艺的经济极限H₂S含量及经济极限处理量的计算公式。 结论上述研究结果对络合铁脱硫工艺技术优选、优化及经济效益的论证、分析具有一定的借鉴作用。      

Desulfurization From Model of Gasoline by Extraction With Synthesized [BF4]−- and [PF6]−-based Ionic Liquids

Abstract

The authors report that 1-octyl-3-methylimidazolium tetrafluoroborate, [OMIM][BF₄], and 1-butyl-3-methylimidazolium hexafluorophosphate, [BMIM][PF₆], ionic liquids were synthesized and tested for their capability to desulfurization from model of gasoline. The results show that the aromatic sulfur compounds with higher π-electron density were favorably adsorbed. The results also show that [BF₄]^?-based ionic liquid displays higher extraction efficiencies than [PF₆]^?-based ionic liquid. Thus, it was shown that the extractive ability of the imidazolium ionic liquids was dominated by the structure of cation and anion. It is also found that the sizes of ionic liquids are important factors affecting the absorption capacity for aromatic sulfur compounds.     

Oxidative Desulfurization of Dibenzothiophene Catalyzed by VO(acac)2 in Ionic Liquids at Room Temperature

A simple extraction and catalytic oxidative desulfurization (ECODS) system composed of VO(acac)₂, 30% H₂O₂, and 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim]BF₄) has been found to be suitable for the deep removal of dibenzothiophene (DBT) in model oil at room temperature. The optimal conditions were as follows: [n(H₂O₂)/n(DBT)/n(catalyst) = 100:20:1], model oil = 5 mL, ionic liquid [IL] = 1 mL, T = 30°C, t = 2 hr. With the ECODS system, the sulfur removal of DBT could reach 99.6%, which was superior to that of the simple extraction with IL (15.6%) or oxidation without catalyst (17.1%). The IL could be recycled five times without a significant decrease in activity.     

Oxidative-extractive desulfurization of liquid fuel using stannous chloride-acetic acid mixture as catalyst

Present study reports catalytic oxidative-extractive desulfurization (COEDS) of model oil (dibenzothiophene (DBT) dissolved in iso-octane) using an acid mixture (composed of Lewis acid and organic acid (glacial acetic acid)) as catalyst and inorganic oxysalt, potassium dichromate, as oxidant. A series of acid mixtures were prepared by mixing different amount of Lewis acids (SnCl₂, CaCl₂ or CuCl₂) in specific amount of acetic acid and tested for the removal of sulfur from model oil. SnCl₂, which performed best as a Lewis acid, was used in further studies. Effect of Lewis acid to sulfur (molar) ratio was studied in the range of 1–5. Effects of other parameters i.e. oxidant to sulfur (O/S) molar ratio, temperature and time on desulfurization efficiency were also investigated. Fourier transform infrared (FTIR) spectroscopy of SnCl₂-CH₃COOH mixture, model oil (before COEDS), raffinate and extract layers was carried out to understand the removal mechanism. Apparent activation energy for COEDS process with SnCl₂-CH₃COOH system was calculated as 11.65 kJ/mol. At the optimized conditions of oxidant to sulfur molar ratio (O/S = 2:1) and Lewis acid to sulfur molar ratio (SnCl₂/S = 5:1), maximum 61.3% sulfur removal was observed from model oil containing 1000 ppm of sulfur at 308 K.     

SELECTIVE REMOVAL OF ORGANIC SULFUR FROM COAL BY PERCHLOROETHYLENE EXTRACTION

ABSTRACT

Desulfurization of coal involves the removal of both the inorganic and organic forms of sulfur. Several physical methods are available for the removal of inorganic sulfur which is normally represented by pyritic and sulfatic sulfur. Removal of organic sulfur requires the use of chemical cleaning methods. This paper presents the results of an organic sulfur removal technique which employs an organic solvent. This desulfurization technique is selective enough to reject organic sulfur without significantly reducing the calorific value of the treated coal. The sulfur containing organic species in the liquid product from the desulfurization procedure have been completely characterized using GC/MS techniques. These results provide further insights into the nature of the sulfur forms in the parent coal as well as the metamorphism of sulfur species in the coal, and the selective nature of the desulfurization process.     

Extractive Desulfurization of Gasoline Using Ionic Liquid Based on CuCl

Abstract

CuCl-based ionic liquid ([HMim]Cl/CuCl) was synthesized by mixing 1-hydracid-3-methylimidazolium chloride ([HMim]Cl) with CuCl. Ionic liquid ([HMim]Cl/CuCl) was employed as an extractant remove sulfur from gasoline. It was found that [HMim]Cl/CuCl can remove sulfur-containing compounds from gasoline at room temperature. The extractive desulfurization mechanism of ionic liquid was proposed. The effects of extractive conditions on desulfurization of gasoline was investigated. The used ionic liquids can be regenerated by re-extraction using tetrachloromethane and reused five times.     

A Study on the Desulfurization Performance of Solvent UDS for Purifying High Sour Natural Gas

Abstract

A desulfurization solvent called UDS was designed and developed based on the differences in desulfurization efficiencies of respective solvent components. The desulfurization performance of UDS was investigated in a simulated industrial unit and the thermal stability as well as the regeneration performance was evaluated using thermogravimetric analysis. The results indicated that the organosulfur removal performance of UDS was significantly enhanced by introducing the sulfur-containing heterocyclic compound and the cyclic amine compound. In the industrial pressure condition of 8.3 MPa, UDS showed around 30 percentage points higher organosulfur removal efficiency than methyldiethanolamine (MDEA). The contents of H₂S and total sulfur were <0.5 and 81.6 mg · m^?3, respectively, in purified gas when adsorption was conducted under gas–liquid volume ratio (V_g/V_l) of 169 and pressure of 1.5 MPa, using UDS. The quality of purified natural gas met first-class standards.     

浅析忠县分厂硫磺回收装置尾气SO2排放影响因素和控制措施

通过对脱硫和硫磺回收装置进行分析可知,影响烟气中SO_2排放的主要工艺因素是原料气气质、气量的波动、酸气组成、脱硫溶液性能及催化剂性能。为了降低硫磺回收装置的SO_2排放,使其达到国家环保要求,主要采取了以下技术措施:①通过控制脱硫溶液质量分数及入塔温度,并适当降低溶液循环量,提高MDEA溶液的选择性;②及时更换失活催化剂;③在常规克劳斯段三级反应器添加SO_2选择性加氢催化剂,减少进入超级克劳斯段的SO_2含量;④优化停产除硫方案,缩短除硫时间。结果表明,采取上述措施后,天然气净化装置的硫回收率稳定较高,排放烟气中SO_2质量浓度达到标准要求。     

Diesel desulfurization using a UV-photocatalytic process

In this paper, the use of ultraviolet irradiation using TiO₂ as a photocatalyst for diesel desulfurization was studied in a batch reactor. The effects of operational parameters such as operation time, the presence of oxidant, oxidant type, and irradiation power on the performance of the desulfurization process were investigated. The results revealed that total sulfur and thiol group removals from diesel samples were about 61.91% and 58.64%, respectively, at the power of 18 W of UV irradiation and 2 wt% H₂O₂ as an oxidizing agent using 40 min of irradiation as an optimum time required. It was also found that hydrogen peroxide is the most promising oxidant for the desulfurization of diesel fuel. By increasing the power of ultraviolet irradiation from 18 W to 30 W, total sulfur removal and thiol group conversion were increased to 90% and 88%, respectively. However, total sulfur removal and thiol group conversion at 30 W ultraviolet irradiation with 2 wt% TiO₂ and without using any oxidants were about zero and 14%, respectively.     

Diesel desulfurization using a ultrasound-assisted oxidative process

In this study, the removal of sulfur compounds from diesel samples using ultrasound-assisted oxidative desulfurization (UAODS) process in presence of different types of oxidizing agents was studied. Experiments were performed to assess the effects of influential parameters on the performance of UAODS process including ultrasonic irradiation time, oxidant type, mass ratio of oxidant to diesel fuel (oxidant: diesel), and finally acetic acid as an oxidative promoter. The efficiency of sulfur compounds removal from the diesel fuel dramatically improved using appropriate oxidative process with the assistance of ultrasound irradiation. H₂O₂ was found to be the most promising oxidant component whose concentration in the media directly affected total sulfur removal and thiol group conversion efficiencies. Using 4 wt% of H₂O₂ followed by 15 min of ultrasonic irradiation leaded to sulfur removal efficiency of 76% and thiol group conversion of 79% at ambient temperature and atmospheric pressure. Using acid acetic as the promoter of H₂O₂ also leaded to further sulfur compounds removal.