Conversion of Bio-syngas to Liquid Hydrocarbon over CuCoMn-Zeolite Bifunctional Catalysts

A series of bifunctional catalysts composed of a component for higher alcohol synthesis （Cu-CoMn oxides, CCM） and an acidic zeolite （SAPO-34, ZSM-5, Y, MCM-41） were prepared for production of liquid hydrocarbon directly from a bio-syngas through a one-stage pro-cess. The effects of zeolite type, zeolite content, Si/Al ratio and preparation method on catalyst texture and its reaction performance were investigated. Higher selectivities and yields of liquid products were obtained by using bifunctional catalysts. The yields of liquid hydrocarbons decreased in the order CCM-ZSM-5〉CCM-SAPO-34〉CCM-Y〉CCM-MCM-41. CCM-ZSM-5 （20wt%, Si/Al=100） prepared by coprecipitation method displayed the optimal catalytic performance with the highest CO conversion （76%） and yield of liquid products （30%）. The catalysts were characterized by N2 adsorption/desorption, NH3-TPD, XRD, and H2-TPR analysis. The results showed that higher speci c surface areas and pore volumes of bifunctional catalysts were achieved by adding zeolites into CuCoMn precursors. Medium pore dimension and moderate acidity in CCM-ZSM-5 were observed, which proba-bly resulted in its excellent reaction performance. Additionally, a higher number of weaker acid sites （weak and/or medium acid sites） were formed by increasing ZSM-5 content in CCM-ZSM-5 or decreasing Si/Al ratio in ZSM-5. It was also seen that metal dispersion was higher and reducibility of metal ions was easier on the CCM-ZSM-5 catalyst prepared by coprecipitation. The higher alcohols-to-hydrocarbon process provides a promising route to hydrocarbon fuels via higher alcohols from syngas or biobased feedstocks.

Characterization and Activity of Cr, Cu and Ga Modified ZSM-5 for Direct Conversion of Methane to Liquid Hydrocarbons

Direct conversion of methane using a metal-loaded ZSM-5 zeolite prepared viaacidic ion exchange was investigated to elucidate the roles of metal and acidity in the formation ofliquid hydrocarbons. ZSM-5 (SiO_2/Al_2O_3=30) was loaded with different metals (Cr, Cu and Ga)according to the acidic ion-exchange method to produce metal-loaded ZSM-5 zeolite catalysts. XRD,NMR, FT-IR and N_2 adsorption analyses indicated that Cr and Ga species managed to occupy thealuminum positions in the ZSM-5 framework. In addition, Cr species were deposited in the pores ofthe structure. However, Cu oxides were deposited on the surface and in the mesopores of the ZSM-5zeolite. An acidity study using TPD-NH_3, FT-IR, and IR-pyridine analyses revealed that the totalnumber of acid sites and the strengths of the Broensted and Lewis acid sites were significantlydifferent after the acidic ion exchange treatment. Cu loaded HZSM-5 is a potential catalyst fordirect conversion of methane to liquid hydrocarbons. The successful production of gasoline via thedirect conversion of methane depends on the amount of aluminum in the zeolite framework and thestrength of the Broensted acid sites.

Methane to Liquid Hydrocarbons over Tungsten-ZSM-5 and Tungsten Loaded Cu/ZSM-5 Catalysts

Metal containing ZSM-5 can produce higher hydrocarbons in methane oxidation. Many researchers have studied the applicability of HZSM-5 and modify ZSM-5 for methane conversion to liquid hydrocarbons, but their research results still lead to low conversion, low selectivity and low heat resistance. The modified HZSM-5, by loading with tungsten （W）, could enhance its heat resistant performance, and the high reaction temperature （800 ℃） did not lead to a loss of the W component by sublimation. The loading of HZSM-5 with tungsten and copper （Cu） resulted in an increment in the methane conversion as well as CO2 and C5＋ selectivities. In contrast, CO, C2-3 and H2O selectivities were reduced. The process of converting methane to liquid hydrocarbons （C5＋） was dependent on the metal surface area and the acidity of the zeolite. High methane conversion and C5＋ selectivity, and low H20 selectivity are obtained over W/3.0Cu/HZSM.

Dual-Bed Catalytic System for Direct Conversion of Methane to Liquid Hydrocarbons

A dual-bed catalytic system is proposed for the direct conversion of methane to liquid hydrocarbons. In this system, methane is converted in the first stage to oxidative coupling of methane （OCM） products by selective catalytic oxidation with oxygen over La-supported MgO catalyst. The second bed, comprising of the HZSM-5 zeolite catalyst, is used for the oligomerization of OCM light hydrocarbon products to liquid hydrocarbons. The effects of temperature （650-800 ℃）, methane to oxygen ratio （4-10）, and SIO2/Al2O3 ratio of the HZSM-5 zeolite catalyst on the process are studied. At higher reaction temperatures, there is considerable dealumination of HZSM-5, and thus its catalytic performance is reduced. The acidity of HZSM-5 in the second bed is responsible for the oligomerization reaction that leads to the formation of liquid hydrocarbons. The activities of the oligomerization sites were unequivocally affected by the SiO2/Al2O3 ratio. The relation between the acidity and the activity of HZSM-5 is studied by means of TPD-NH3 techniques. The rise in oxygen concentration is not beneficial for the C5＋ selectivity, where the combustion reaction of intermediate hydrocarbon products that leads to the formation of carbon oxide （CO＋CO2） products is more dominant than the oligomerization reaction. The dual-bed catalytic system is highly potential for directly converting methane to liquid fuels.

Separation of light hydrocarbons with ionic liquids: A review

Light hydrocarbons(C1–C4) are fundamental raw materials in the petroleum and chemical industry. Separation and purification of structurally similar paraffin/olefin/alkyne mixtures are important for the production of highpurity or even polymer-grade light hydrocarbons. However, traditional methods such as cryogenic distillation and solvent absorption are energy-intensive and environmentally unfriendly processes. Ionic liquids(ILs) as a new alternative to organic solvents have been proposed as promising green media for light hydrocarbon separation due to their unique tunable structures and physicochemical properties resulting from the variations of the cations and anions such as low volatility, high thermal stability, large liquidus range, good miscibility with light hydrocarbons, excellent molecular recognition ability and adjustable hydrophylicity/hydrophobicity. In this review, the recent progresses on the light hydrocarbon separation using ILs are summarized, and some parameters of ILs that influence the separation performance are discussed.

Optimization of Ultrasonic Extraction and Clean-up Protocol for the Determination of Polycyclic Aromatic Hydrocarbons in Marine Sediments by High-performance Liquid Chroma-tography Coupled with Fluorescence Detection

The procedures of ultrasonic extraction and clean-up were optimized for the determination of polycyclic aromatic hydrocarbons (PAHs) in marine sediments. Samples were ultrasonically extracted, and the extracts were purified with a miniaturized silica gel chromatographic column and analyzed with high performance liquid chromatography (HPLC) with a fluorescence detector. Ultrasonication with methanol-dichloromethane (2:1, v/v) mixture gave higher extraction efficiency than that with dichloromethane. Among the three elution solvents used in clean-up step, dichloromethane-hexane (2:3, v/v) mixture was the most satisfactory. Under the optimized conditions, the recoveries in the range of 54.82% to 94.70% with RSDs of 3.02% to 23.22% for a spiked blank, and in the range of 61.20% to 127.08% with RSDs of 7.61% to 26.93% for a spiked matrix, were obtained for the 15 PAHs studied, while the recoveries for a NIST standard reference SRM 1941b were in the range of 50.79% to 83.78% with RSDs of 5.24% to 21.38%. The detection limits were between 0.75 ng L-1 and 10.99 ng L-1for different PAHs. A sample from the Jiaozhou Bay area was examined to test the established methods.

Use of Ionic Liquid-filled Semipermeable Membrane for Extraction of Polycyclic Aromatic Hydrocarbons in Water

A novel and facile sample preparation method was developed for the extraction of polycyclic aromatic hydrocarbons (PAHs) in aqueous sample solution using 1-butyl-3- methylimidazolium hexafluorophosphate ([C4MIM][PF6]) – filled semipermeable membrane. For 24 hrs extraction of naphthalene, 1-methylnaphthalene, 2-chloronaphthalene, phenanthrene, the result showed that the extraction efficiency, correlation coefficient (R2) and RSD (n=5) were in the range of 67-102 %, 0.9870-0.9962, and 2.1-5.3 %, respectively.

Determination of Trace Amount of Polycyclic Aromatic Hydrocarbons in Urban Sewage by Solid-phase Extraction Coupled with High Performance Liquid Chromatograph

[Method] This study aimed to determine trace amount of polycyclic aromatic hydrocarbons(PAHs) in urban sewage by using solid-phase extraction(SPE) coupled with high performance liquid chromatograph(HPLC).[Method] From the aspects of solid-phase extraction column,elution solvent,elution volume,elution speed and so forth,the test conditions of SPE-HPLC method were optimized,and trace amount of PAHs in urban sewage was determined.[Result] The optimized solid-phase extraction conditions were SUPELCLEAN LC-18 solid-phase extraction column,methylene dichloride as elution solvent,15 ml elution volume,2 ml/min elution speed,5 ml/min loading speed,1 000 ml water with 200 ml methanol loading volume.Under the optimized extraction conditions,the recovery was high,namely 76.3%-105.2%;relative standard deviation was 3.8%-6.0%,showing good precision;detection limit was low,only 0.000 8-0.048 0 μg/L.[Conclusion] This method is user-friendly,with high sensitivity and good precision,and suitable for continuous determination of a large volume of water samples.

On-line enrichment and determination of polycyclic aromatic hydrocarbons in atmospheric particulates using high performance liquid chromatography with fluorescence as detector

Seven polycyclic aromatic hydrocarbons （PAHs） in atmospheric particulates were determinated by high performance liquid chromatography （HPLC） with fluorescence detector using direction injection and an on-line enrichment trap column. The method simplified the sample pretreatment, saved time and increased the efficiency. With the on-line trap column, PAHs were separated availably even underground injecting 1.0 ml sample with relatively high column efficiency. The recoveries of the seven PAHs were from 85% to 120% for spiked atmospheric particulate sample. The limit of detection was 15.3-39.6 ng/L （S/N=3.3）. There were good linear correlations between the peak areas and concentrations of the seven kinds of PAHs in the range of 1-50 ng/ml with the correlation coefficients over 0.9970. Furthermore, it also indicated that the method is available to determine PAHs in atmospheric particulates well.

纤维素生物质与废塑料共催化热解制取富烃液体燃料的研究进展

生物质能是国际公认的零碳可再生能源,其高效利用成为缓解能源与环境危机的关键,并对中国实现“碳达峰”和“碳中和”的目标具有重要意义。纤维素生物质与废塑料的共催化热解技术,不仅能制备高附加值的富烃液体燃料,还可达到“以废治废”的目的,进而实现生物质与废塑料的高效资源化利用。本工作从生物质与废塑料高值化利用的角度出发,对生物质和废塑料共催化热解制备富烃液体燃料的研究现状进行了综述,介绍了纤维素生物质和废塑料的基础化学特性差异,论述了废塑料种类、催化剂种类、物料和催化剂比例、催化热解温度等因素对生物质和废塑料共催化热解生物油产率和品质的影响,阐述了生物质和废塑料单独催化热解过程中的化学反应机理,并揭示了共催化热解过程中的协同反应机理,展望了该领域未来的发展方向,为生物质与废塑料的高附加值利用提供参考与思路。

溶剂提取-高效液相色谱法测定大气颗粒物中18种多环芳烃

建立大气颗粒物PM2.5中18种多环芳烃的样品快速溶剂提取结合高效液相色谱的测定方法。将1/2玻璃滤膜剪碎后加入2.0 mL乙腈,于20℃水浴超声提取30 min,提取液经0.22μm有机相滤膜过滤,多环芳烃C18专用柱分离,以乙腈-水作为流动相进行梯度洗脱,采用紫外串联荧光检测器-高效液相色谱仪检测,以色谱峰面积外标法定量。18种PAHs的质量浓度在0.01~0.50μg/mL范围内与色谱峰面积线性关系良好,相关系数不小于0.999,检出限为0.03~0.47 ng/m^(3),样品加标平均回收率为75.6%~114.7%,相对标准偏差为0.09%~3.78%(n=7)。该方法简便、快速、准确、灵敏,可应用于大气颗粒物PM2.5中18种多环芳烃的测定。

液液萃取--超高效液相色谱串联质谱法同时测定尿中11种羟基多环芳烃

目的建立可同时测定尿中11种羟基多环芳烃(hydroxy-polycyclic aromatic hydrocarbons,OH-PAHs)的超高效液相色谱串联质谱分析(ultra-high performance liquid chromatography tandem with mass spectrometry,UPLC-MS/MS)法。方法尿液样品在pH=5.5条件下,在37℃水浴中经β-葡萄糖苷酸酶—芳基硫酸酯酶避光水解16 h,3.0 mL正己烷萃取、涡旋、离心,取上层有机相,重复萃取两次,合并萃取液,氮吹至近干,再复溶于20%乙腈水溶液中。流动相为水和10%异丙醇甲醇溶液,梯度洗脱模式洗脱,CORTECS C18色谱柱分离,ESI-模式测定尿液中11种羟基多环芳烃浓度,内标法定量分析。结果11种羟基多环芳烃线性关系良好,相关系数(r)均大于0.997。方法的检出限为0.01~0.10 ng/mL;日间回收率为79.8%~97.3%,精密度为1.9%~4.7%(n=3);日内回收率为78.6%~92.3%,精密度为3.7%~7.1%(n=3)。结论该方灵敏度高,准确可靠,适用于人群中多种羟基多环芳烃的监测。

生物质预处理催化热解制备液体燃料研究进展

随着能源需求的不断增长和环境问题的日益突出,生物质催化热解制备液体燃料技术成为一种可持续发展的能源利用方式。生物质直接热解生成的生物油成分复杂、热值低、含氧量高、酸性强,制约了生物油的应用。从热解机理、生物质预处理、催化剂和预处理和催化耦合技术等方面综述了影响生物油品质的主要因素。指出预处理技术普遍存在时间长的缺点,使用催化剂会导致生物油产率的降低,而预处理和催化耦合技术有望突破这2项技术难点;生物质快速热解定向制备富烃生物油、催化剂的选择与优化、预处理和催化耦合技术将是生物质快速热解制备高品质液体燃料的主要研究方向。

Review on the Relationship Between Liquid Aerospace Fuel Composition and Their Physicochemical Properties

The development of advanced air transportation has raised new demands for high-performance liquid hydrocarbon fuels.However,the measurement of fuel properties is time-consuming,cost-intensive,and limited to the operating conditions.The physicochemical properties of aerospace fuels are directly infl uenced by chemical composition.Thus,a thorough investigation should be conducted on the inherent relationship between fuel properties and composition for the design and synthesis of high-grade fuels and the prediction of fuel properties in the future.This work summarized the eff ects of fuel composition and hydrocarbon molecular structure on the fuel physicochemical properties,including density,net heat of combustion(NHOC),low-temperature fl uidity(viscosity and freezing point),fl ash point,and thermal-oxidative stability.Several correlations and predictions of fuel properties from chemical composition were reviewed.Additionally,we correlated the fuel properties with hydrogen/carbon molar ratios(n H/C)and molecular weight(M).The results from the least-square method implicate that the coupling of H/C molar ratio and M is suitable for the estimation of density,NHOC,viscosity and eff ectiveness for the design,manufacture,and evaluation of aviation hydrocarbon fuels.

Optimization of methane conversion to liquid fuels over W-Cu/ZSM-5 catalysts by response surface methodology

The conversion of methane to liquid fuels is still in the development process. The modified HZSM-5 by loading with Tungsten （W） enhanced its heat resistant performance, and the high reaction temperature （800℃） did not lead to the loss of W component by sublimation. The loading of ZSM-5 with Tungsten and Copper （Cu） resulted in an increment in the methane conversion, CO2, and C5＋ selectivities. The high methane conversion and C5＋ selectivity, and low H2O selectivity are obtained by using W/3.0Cu/ZSM-5. The optimization of methane conversion over 3.0 W/3.0Cu/ZSM-5 under different temperature and oxygen concentration using response surface methodology （RSM） are studied. The optimum point for methane conversion is 19% when temperature is 753 ℃, and oxygen concentration is 12%. The highest C5＋ selectivity is 27% when temperature is 751 ℃. and oxwen concentration is 11%.

液液萃取/气相色谱-串联质谱法测定人尿中16种羟基多环芳烃

建立了同时测定人尿中16种羟基多环芳烃(OH-PAHs)的液液萃取/气相色谱-串联质谱法(LLE/GCMS/MS)。1 mL尿样经β-葡萄糖苷酸酶/硫酸芳酯酶酶解后,使用甲苯和正戊烷(1∶4)混合溶剂重复提取两次,提取液经硝酸银溶液除杂后氮吹浓缩至近干,甲苯复溶后加入N-甲基-N-(三甲基硅烷)三氟乙酰胺(MSTFA)进行衍生化反应后待测。待测物经TG-5SilMS毛细管色谱柱分离,在多反应监测(MRM)模式下以内标法定量。该研究对衍生化反应条件、仪器参数、酶添加量、提取溶剂进行比较和优化,评估了基质效应,并考察了方法的精密度和准确度。结果表明,1-羟基萘(1-NAP)和2-羟基萘(2-NAP)在0.1~100μg/L范围内线性关系良好,其他目标物在0.02~20μg/L范围内线性关系良好,方法检出限为0.01~0.19μg/L,定量下限为0.03~0.62μg/L,加标回收率为81.6%~122%,日内和日间相对标准偏差(RSD)分别为0.22%~5.5%和0.76%~10%,标准参考样品SRM 3672测定结果与参考值的相对偏差均小于10%。应用该方法测定国家人体生物监测项目采集的529份尿样,结果显示除3-羟基屈(3-CHR)外,其他15种OH-PAHs均检出,8种目标物的检出率超过90%。1-NAP和2-NAP的质量浓度水平高于其他组分,中位数分别为1.09μg/L和1.95μg/L。该方法成本低、分离度好、灵敏度高、基质效应干扰小,适用于普通人群尿中OH-PAHs负荷水平的监测。

液相色谱在柴油多环芳烃分析中的应用

本文旨在应用高效液相色谱(HPLC)技术对柴油中的多环芳烃(PAHs)进行定性和定量分析。PAHs是一类具有高毒性和致癌性的有机化合物,对环境和人体健康构成严重威胁。实验中,通过液液萃取法提取柴油样品中的PAHs,使用氰基键合硅胶固定相进行色谱分析。结果表明,所采用的HPLC方法能够有效分离和检测柴油中的多种PAHs,具有较高的分辨率和灵敏度。主要检测的PAHs包括双环芳烃(DAHs)和三环芳烃(T+AHs)。实验结果显示,不同PAHs在柴油中的浓度分布反映了其燃烧特性和污染来源。该方法的有效性和可靠性在实验中得到了验证,但样品前处理和色谱条件的优化仍有改进空间。本文的研究为柴油中PAHs的分析提供了一个有效的技术手段,对环境监测和污染控制具有重要意义。

Ni-Pt/MgAl_(2)O_(4)双金属催化剂构筑及其对不同构型烃类蒸汽重整制氢性能的影响

航空煤油成分复杂,由上百种不同构型的烃类组成,然而正构烷烃、异构烷烃、环烷烃和芳香烃这几类主要组分的构型和性质差异甚大,导致其蒸汽重整反应特性存在较大差异。本论文在前期研发Ni/MgAl_(2)O_(4)基础上,引入Pt构建Ni-Pt双金属催化剂,系统考察了该催化剂对不同构型组分重整反应性能的差异,并对不同构型组分在该催化剂上的重整反应路径进行了阐述。结果表明:液相还原法引人Pt能够使双金属催化剂具有合适的酸性和良好的金属Ni分散性,Ni-Pt两种金属协同效应,不仅能够提高单Ni催化剂活性,同时能够减少Ni烧结,优化催化剂稳定性;另外,不同构型组分在双金属催化剂上的重整性能具有显著差异,其中正癸烷重整的产气率以及H,选择性较为优异。不同构型烃类燃料的反应活性为:甲基环已烷>正癸烷>乙苯。由于甲基环已烷在反应过程中C-C键键能弱,易开环形成链状自由基与水发生重整反应,乙苯具有芳香烃结构且不易开环,重整反应所需能量较高。

液相色谱-串联质谱法定量检测油脂中16种多环芳烃

目的建立液相色谱-串联质谱法同时测定食用油中16种多环芳烃(polycyclic aromatic hydrocarbons,PAHs)含量的方法。方法油脂经乙腈提取处理后,采用柱纯化技术对PAHs进行富集,通过液相色谱-串联质谱仪进行检测。重点优化离子源的选择,色谱柱的优化,提取溶剂和提取溶剂体积以及洗脱溶液的选择等。确定最优前处理方法为5 mL乙腈提取,PAH固相萃取柱净化并用15 mL乙酸乙酯:二氯甲烷(V:V=1:1)洗脱。最优检测条件为使用大气压化学电离源在正离子模式下进行离子化,使用EclipsePAH液相色谱柱进行分离。结果16种PAHs在0.1~500.0μg/L的质量浓度范围内呈现良好的线性关系,检出限在0.04~1.72μg/kg,定量限在0.11~17.01μg/kg,加标回收率有最优值为75.71%~117.60%,日内相对标准偏差为0.09%~8.00%,日间相对标准偏差为0.10%~8.18%。结论该方法可准确提取并检测出16种PAHs,提高食用油中PAHs的检测效率,为食用油的安全性评价提供了方法支撑。

高效液相色谱法对长链烷基芳烃的组分分析研究

烷基化芳烃作为第四代合成油系列产物,因其性能优异而受到广泛关注,其中长链烷基芳烃由于碳数较大、沸点较高而难以气化、相对成分较为复杂,给组分分析带来很大困难。利用高效液相色谱法对长链烷基芳烃的各组分进行了分析,分别探讨了紫外检测波长、流速以及流动相的极性等参数对色谱分析结果的影响,并总结出一种适于长链烷基芳烃组分分析的方法。研究结果可为分析长链烷基芳烃相关产品提供一定的理论指导。