Desulfurization of gasoline by condensation of thiophenes with formaldehyde in a biphasic system using aqueous phase of acids

Aqueous phase of acids as catalysts for the desulfurization of gasoline by condensation of thiophenes with formaldehyde in a biphasic system was investigated. Two types of model gasoline with and without aromatics and olefins were employed in this work. The desulfurization rates were above 90% on these two types of model gasoline using formic acid and H_3PW_(12)O_(40)(0.8 mol·L~(-1)), indicating that the presence of aromatics and olefins has no effect on the desulfurization rate. High temperature(above 90 °C) was more favorable to the process for desulfurization. Four hours was considered to be the proper treating time for the sulfur removal. In addition,aqueous phase of acids could be recycled at least 4 times without decreasing desulfurization rate. Finally, the possible process for the integration of condensation desulfurization into the existing refinery process for the production of gasoline with low sulfur content was proposed.     

金属担载分子筛对含硫模型化合物和含硫烃的催化裂化脱硫反应的影响

Zn, La, Zr, Sn and Ti loaded molecular sieves were prepared by impregnation method. Conversions of benzothiophene and dibenzothiophene over the metal oxides modified ultra stable zeolite Y(USY), ZSM-5, β and MSU-2 molecular sieve catalysts were investigated by means of micro-activity test (MAT) experiments. The results showed that Zn and La loaded catalysts were better than the other metals, and ZSM-5 with lower SiO2/Al2O3 mole ratio showed better results than those with higher SiO2/Al2O3 as far as desulfurization reaction is considered. A comparison of the desulfurization activities of the La/Zn-USY catalyst with USY catalyst indicated that the bimetal loaded USY catalyst gave good products selectivity when sulfur containing heavy oil was used as the feedstock. The sulfur content in gasoline fraction was decreased by 25%, and there was no loss in the Research Octane Number.     

Desulfurization of liquid hydrocarbon fuels via Cu_2O catalyzed photooxidation coupled with liquid–liquid extraction

By combining the photochemical reaction and liquid–liquid extraction(PODS), we studied desulfurization of model fuel and FCC gasoline. The effects of air flow, illumination time, extractants, volume ratios of extractant/fuel, and catalyst amounts on the desulfurization process of PODS were analyzed in detail. Under the conditions with the air as oxidant(150 ml·min~(-1)), the mixture of DMF–water as extractant(the volume ratio of extractant/oil of 0.5) and photo-irradiation time of 2 h, the sulfur removal rate reached only 42.63% and 39.54% for the model and FCC gasoline, respectively. Under the same conditions, the sulfur removal rate increased significantly up to79% for gasoline in the presence of Cu_2O catalyst(2 g·L~(-1)). The results suggest that the PODS combined with a Cu_2O catalyst seems to be a promising alternative for sulfur removal of gasoline.     

用过氧化氢和乙酸对未经氢化处理的煤油进行直接氧化脱硫

The oxidative desulfurization of a real refinery feedstock (i.e., non-hydrotreated kerosene with total sulfur mass content of 0.16%) with a mixture of hydrogen peroxide and acetic acid was studied. The influences of various operating parameters including reaction temperature (T), acid to sulfur molar ratio (nacid/nS), and oxidant to sulfur molar ratio (nO/nS) on the sulfur removal of kerosene were investigated. The results revealed that an increase in the reaction temperature (T) and nacid/nS enhances the sulfur removal. Moreover, there is an optimum nO/nS related to the reaction temperature and the best sulfur removal could be obtained at nO/nS 8 and 23 for the reaction temperatures of 25 and 60C, respectively. The maximum observed sulfur removal in the present oxidative desulfurization system was 83.3%.     

Optimization of a continuous ultrasound assisted oxidative desulfurization (UAOD) process of diesel using response surface methodology (RSM) considering operating cost

A continuous-flow ultrasound-assisted oxidative desulfurization(UAOD) of partially hydro-treated diesel has been investigated using hydrogen peroxide-formic acid as simple and easy to apply oxidation system. The effects of different operating parameters of oxidation stage including residence time(2–24 min), formic acid to sulfur molar ratio(10–150), and oxidant to sulfur molar ratio(5–35) on the sulfur removal have been studied using response surface methodology(RSM) based on Box–Behnken design. Considering the operating costs of the continuous-flow oxidation stage including chemical and electrical energy consumption, the appropriate values of operating parameters were selected as follows: residence time of 16 min, the formic acid to sulfur molar ratio of 54.47, and the oxidant to sulfur molar ratio of 8.24. In these conditions, the sulfur removal and the volume ratio of the hydrocarbon phase to the aqueous phase were 86.90% and 4.34, respectively. By drastic reduction in the chemical consumption in the oxidation stage, the volume ratio of the hydrocarbon phase to the aqueous phase was increased up to 10. Therefore, the formic acid to sulfur molar ratio and the oxidant to sulfur molar ratio were obtained 23.64 and 3.58, respectively, which lead to sulfur removal of 84.38% with considerable improvements on the operating cost of oxidation stage in comparison with the previous works.     

硅橡胶复合膜渗透汽化分离硫/汽油混合物

Worldwide environment has resulted in a limit on the sulfur content of gasoline. It is urgent to investigate the desulfurization of gasoline. The polydimethylsiloxane (PDMS)/polyetherimide (PEI) composite membranes were prepared by casting a PDMS solution onto porous PEI substrates and characterized by scanning electron microscope (SEM). The membranes were used for sulfur removal from gasoline by pervaporation. The effects of feed temperature, sulfur content in the feed and PDMS layer thickness on membrane performance were investigated, and an activation energy of permeation was obtained. Experimental results indicated that higher feed temperature yielded higher total flux and lower sulfur enrichment factor. The total flux varied little with the increase of sulfur content in the feed, but the sulfur enrichment factor first increased with the amount of thiophene added into the gasoline, and then the variation was little. The increase of PDMS layer thickness resulted in a smaller flux but a larger sulfur enrichment factor. The result indicates that the PDMS/PEI composite membranes are promising for desulfurization by pervaporation.     

计算传质法预测精馏塔效率(英文)

A computational mass transfer model is proposed for predicting the concentration profile and Murphree efficiency of sieve tray distillation column. The proposed model is based on using modified two equations formulation for closing the differential turbulent mass transfer equation with improvement by considering the vapor injected from the sieve hole to be three dimensional. The predicted concentration distributions by using proposed model were checked by experimental work conducted on a sieve tray simulator of 1.2 meters in diameter for de-sorbing the dissolved oxygen in the feed water by blowing air. The model predictions were confirmed by the ex-perimental measurement. The validation of the proposed model was further tested by comparing the simulated re-sult with the performance of an industrial scale sieve tray distillation column reported by Kunesh et al. for the strip-ping of toluene from its water solution. The predicted outlet concentration of each tray and the Murphree tray effi-ciencies under different operating conditions were in agreement with the published data. The simulated turbulent mass transfer diffusivity on each tray was within the range of the experimental result in the same sieve column re-ported by Cai et al. In addition, the prediction of the influence of sieve tray structure on the tray efficiency by using the proposed model was demonstrated.     

离子液体介质中沥青砂内重组分降解过程

This paper illustrates the reaction pattern of catalytic degradation of macromolecules in asphaltic sands. Such parameters as ionic liquid catalyst system and H^ proton donor, that affect the change of the organic phase and the mass of organic matter in residual phase of asphaltic sands, were investigated. It was found that chloroaluminate (Ⅲ) ionic liquid/H3PO4 systems as reaction medium was an effective catalyst system for asphaltic sands degradation. The catalytic degradation of asphaltic sand swas related to the kinds of chloroaluminate (Ⅲ) ionic liquids and H^ proton donor. In [BMIM] [AlCl4]/H3PO4 reaction catalytic medium, the degradation of asphaltenes in the organic phase reached 16.44 %, the degradation of asphaltenes in the residual phase reached 30.74%. TLC-FID analysis of asphaltic sands showed that the main degradation products were saturates and aromatics, and resin fractions as well. At a temperature close to oil-bearing formation and with absense of oxygen, the yield of H2S reached 74%,which indicated that catalytic degradation of sulphur-containing compounds was easier.     

富镧稀土镍-苯浆液体系中液相苯加氢反应动力学研究

The kinetics of liquid-phase hydrogenation of benzene in misch metal nickel-five (MlNi5) and benzene slurry system was studied by investigating the influences of the reaction temperature, pressure, alloy concentration and stirring speed on the mass transfer-reaction processes inside the slurry. The results show that the whole process is controlled by the reaction at the surface of the catalyst. The mass transfer resistance at gas-liquid interface and that from the bulk liquid phase to the surface of the catalyst particles are negligible. The apparent reaction rate is zero order for benzene concentration and first order for hydrogen concentration in the liquid phase. The kinetic model obtained fits the experimental data very well. The apparent activation energy of the hydrogen absorption reaction of MlNi5-C6H6 slurry system is 42.16 kJ.mol-1.     

模拟城市垃圾焚烧中硫化合物对重金属Cd迁移分布的影响

The effect of sulfur compounds （including sulfur, sulfide, sulfite and sulfate）, initial concentration of heavy metal and operating conditions on Cd emission in municipal solid waste （MSW） incineration were investi-gated using a simulated tubular furnace and simulated MSW spiked with Cd. The concentration of Cd was meas-ured by inductively coupled plasma-atomic emission spectrometry （ICP-AES） after digesting the samples including bottom ash, fly ash and flue gas according to related USEPA methods. The results show that S and Na2S tend to in- crease Cd partitioning in bottom ash, whereas Na2SO3 and Na2SO4 tend to reduce Cd partitioning in bottom ash. The effect of sulfur compounds on Cd partitioning in bottom ash was in the sequence of Na2S〉S〉Na2SO3〉 Na2SO4. chemical equilibrium analysis is also performed to determine the effect of sorbents on Cd adsorption. The calculations show that S presents strong affinity for Cd and restrains Cd adsorption by SiO2, whereas when temperature rises to between 830℃ and 1030℃, Cd adsorption efficiency of SiO2 is over 80% and the efficiency of Al2O3 is up to 85%.     

硅胶催化双氧水甲酸氧化噻吩类化合物的研究

1 INTRODUCTION Due to growing environmental concern to impact of sulfur oxides contained in engine exhaust emissions, sulfur content specifications in light oils are becoming more and more stringent worldwide[1,2]. The necessity of producing low sulfur fuels to meet new regulation mandates requires new desulfurization techniques. As for the current hydrodesulfurization (HDS) technology, higher temperature, higher pressure, larger reactor volume, and more active catalysts are unavoidable,…     

催化裂化汽油中特征硫化物噻吩的催化氧化脱硫

以负载金属铈的分子筛为催化剂,在H2O2-HCOOH体系中,对催化裂化（FCC）汽油中特征硫化物噻吩（C4H4S）的正庚烷溶液进行了氧化脱硫研究。考察了氧化剂用量、溶剂、氧化时间、氧化温度、相转移剂等因素对噻吩脱除效果的影响,并对对噻吩的氧化反应历程进行了初步的探讨。实验结果表明：以负载金属铈的分子筛为催化剂,在反应温度50℃,反应60min, H2O2：S＝10：1（mol/mol）,H2O2：HCOOH＝1：1（V/V）的条件下,正庚烷溶液C4H4S的脱除率达到了78.2％,加入乳化剂OP可使C4H4S的脱硫率达到94.5％,但四丁基溴化胺（TBAB）的加入使氧化后的样品中出现了噻吩的溴代产物。     

相转移催化氧化脱除噻吩的应用研究

以噻吩溶液为模型化合物,应用季铵盐类相转移催化剂,对FCC汽油相转移催化氧化-萃取脱硫工艺进行了系统研究。考察了相转移催化剂、氧化时间、氧化温度、氧化剂加入量等工艺条件对脱硫率的影响。研究结果表明,季铵盐相转移催化剂的阴阳离子对脱硫率有重要影响。以四丁基溴化铵(TBAB)为相转移催化剂,反应温度40℃,反应时间150 min,氧化剂用量为n(H2O2):n(S)=4,萃取剂为二甲基亚砜时脱硫率可达93.1%。     

S Zorb反应吸附脱硫反应过程的热力学分析

S Zorb技术可以将FCC汽油的硫含量降至小于10μg/g,但在反应吸附脱硫过程中,由于反应体系中引入了H2,在反应器中不仅发生了硫化物的脱硫反应,还会发生不饱和烃的加氢饱和反应、加氢异构化反应和烯烃与H2S生成硫醇的反应。本文采用基团贡献法Benson法分析了这些反应的热力学性质,计算了这些反应的反应焓变?rHm、反应吉布斯自由能?rGm和反应平衡常数K及平衡转化率。计算结果表明,本文所列举的7个典型反应都是放热反应,且有芳烃加氢放热＞噻吩化合物脱硫放热＞烯烃加氢放热＞烯烃与H2S生成硫醇放热＞烯烃加氢异构放热;在S Zorb反应吸附过程中,体系中H2S含量较少,因此噻吩脱硫后不会继续生成硫醇。     

裂解汽油一段加氢用Ni/Al_2O_3催化剂CS_2中毒研究

采用固定床反应器研究了Ni/Al2O3上CS2对裂解汽油原料油中主要化合物芳烃、单烯烃和共轭烯烃加氢活性的影响,其对加氢抑制的顺序为:芳烃单烯烃共轭烯烃。XRD、XPS和IR表征分析表明,Ni/Al2O3催化剂失活的可能原因是CS2吸附在活性相表面,部分CS2碳硫键断裂发生氢解反应产生H2S和CH4,H2S与镍活性中心作用形成镍硫化合物。原料油中部分CS2吸附在催化剂表面,催化剂对共轭烯烃加氢也失去活性。     

催化裂化汽油加氢脱硫技术的研究

在分析催化裂化汽油硫和烯烃分布不均匀的基础上,对全馏分催化裂化汽油选择性预加氢后再分馏,开发出活性高和稳定性好的催化裂化汽油加氢脱硫催化剂及工艺技术。结果表明,产品汽油硫含量由196.2×10^-6降至39.2×10^-6,加氢脱硫率80.1%,硫醇由33.8×10^-6降至5.95×10^-6,烯烃体积分数较原料油降低了2.1个百分点, 研究法辛烷值损失0.5个单位,收率99.24%,可生产满足国Ⅳ清洁标准的汽油调和组分。     

活性炭催化氧化脱除汽油和柴油中噻吩类硫化物的选择性

研究了活性炭催化氧化脱除汽油和柴油中噻吩类硫化物的选择性。采用气相色谱-硫化学发光检测器（GC-SCD）分析了汽油和柴油中噻吩类硫化物的分布及浓度;以活性炭作为催化剂,以30％过氧化氢溶液为氧化剂,在甲酸存在条件下考察了汽油和柴油中噻吩类硫化物催化氧化脱除的选择性,讨论了硫化物中硫原子电子密度对硫化物氧化选择性的影响。结果表明：汽油中噻吩类硫化物主要有噻吩（T）及其烷基衍生物（T alkylated derivatives）和苯并噻吩（BT）;而柴油中噻吩类硫化物主要分布有苯并噻吩(BT)及其烷基衍生物(BT alkylated derivatives)和二苯并噻吩（DBT）及其烷基衍生物（DBT alkylated derivatives）;硫原子电子密度大于5.716的含3个C烷基噻吩（C3-T）、BT、BT alkylated derivatives、DBT 和DBT alkylated derivatives 能被催化氧化脱除,硫原子的电子密度越大,其被氧化的速率越快,被脱除的选择性也越大;被脱除选择性顺序为：DBT alkylated derivatives > DBT > BT alkylated derivatives> BT> C3-T;然而硫原子电子密度小于5.716的T,含1个烷基噻吩（C1-T）和含2个C烷基噻吩（C2-T）则不能被氧化脱除。采用此方法,能将初始硫浓度为1200 μg•g^-1的柴油降低至小于10 μg•g^-1,可将初始硫浓度为320 μg•g^-1的汽油降低至155 μg•g^-1。     

催化裂化汽油降烯烃助剂的开发研究

基于催化裂化催化剂降烯烃方面的研究进展，在现有催化裂化金属钝化剂的基础上，围绕提高氢转移活性，提出制备降烯烃催化裂化助剂的技术路线，并研制开发了新型降烯烃催化裂化助剂。实验结果显示，降烯烃助剂不仅具有良好的抗重金属污染的特性，而且能有效地降低汽油中的烯烃含量，其具有较高的氢转移活性，可协调芳构化与氢转移反应，同时也改善了催化裂化产品分布。     

FCC汽油加氢脱硫/降烯烃工艺技术的研究

在分析催化裂化汽油硫和烯烃分布不均匀的基础上,对催化裂化汽油进行分馏,开发出了活性高和稳定性好的重馏分辛烷值改进催化剂和选择性加氢脱硫催化剂及其工艺技术。采用该工艺技术对RFCC汽油进行轻馏分碱洗抽提脱硫醇,重馏分辛烷值改进/选择性加氢脱硫等改质处理,再按分馏比例回调,产品汽油烯烃含量为24.2v%,较原料油降低了16.0v%,芳烃含量为19.2v%,较原料油提高了4.1v%,硫含量为41.5ppm,总脱硫率为85.46%,RON为87.8,较原料油提高0.4个单位,液收99.1%,可生产符合国Ⅳ规范的清洁汽油。