生产清洁汽油催化技术进展

针对世界各国清洁汽油的发展趋势,叙述和分析了中国在生产清洁汽油方面的现状和各种生产清洁燃料的新技术,尤其是生产低硫、超低硫汽油技术。介绍了汽油中硫化物的来源和组成,分析了国内外汽油质量规格标准的进展,着重讨论了催化裂化(FCC)汽油脱硫技术及其经济性。     

Prediction of properties of diesel/biodiesel blends by infrared spectroscopy and multivariate calibration

Partial least squares models (PLS) using near and middle infrared spectrometry were developed to predict quality parameters of diesel/biodiesel blends (density, sulphur content and distillation temperatures). Practical aspects are discussed, such as calibration set composition; model efficiency using different infrared regions and spectrometers; and the calibration transfer problem. The root mean square errors of prediction, employing both regions and equipment, were comparable with the reproducibility of the corresponding standard method for the properties investigated. Calibration transfer between the two instruments, using direct standardization (DS), yielded prediction errors comparable to those obtained with complete recalibration of the secondary instrument.     

车用汽油辛烷值促进剂的应用现状及研究进展

综述了当前车用汽油辛烷值促进剂的种类、使用情况和应用现状,认为相对金属类抗爆剂而言,有机无灰类抗爆剂不仅绿色环保而且对发动机无磨损,是今后车用汽油辛烷值促进剂发展的主要方向。SHD-T是一种新型高效汽油辛烷值促进剂,不仅添加剂量小,辛烷值提升幅度大,而且绿色无污染,是一种性能优异的抗爆剂产品。     

从专利角度看清洁汽油生产工艺研究现状

根据国务院部署的蓝天保卫战,2019年1月1日起,国内开始供应符合国VI标准的车用汽油,开发"低硫、低烯、低芳烃、高辛烷值"的"三低一高"清洁汽油生产新技术成为当前研究趋势。为符合最新的国家汽油标准,众多科研院所和石化企业均投入人力物力对现有汽油生产工艺进行升级开发,为国VI标准汽油的供应提供了保障。主要从专利角度介绍了清洁汽油的研究现状。     

Characterization of water in bacterial cellulose using dielectric spectroscopy and electron microscopy

It is shown that only 10% of the 99 wt% water present in bacterial cellulose (BC) gels, produced by Acetobacter xylinum, behave like free bulk water; the majority of the water molecules in the gels is more or less tightly bound to the cellulose. The magnitude of the diffusion coefficients of ions transported in the water phase of the BC gels as well as the information contained in freeze fracture transmission electron microscopic images of the gel structures indicates that the bulk-like water is confined in “lakes” rather than forming a continuous phase throughout the gel. Water desorption isotherms suggest that these “lakes” decrease in size with increasing oxygen concentration used during the biosynthesis process of the gels.     

Simultaneous enhancement of ethanol supplement in gasoline and its quality improvement

Ethanol and ethanol derivatives are attractive renewable energy resources nowadays. Even though ethanol can be blended directly into gasoline (called “gasohol”), many recent researches have reported disadvantages of gasohol. Apart from immiscibility and corrosion problems, overall air pollutant emissions from the use of gasohol are usually higher than those from the use of conventional gasoline because of its higher blending Reid vapor pressure (bRvp). Ethers derived from ethanol may overcome these drawbacks. Direct etherification of FCC gasoline with ethanol was investigated in this work. The reactions were carried out in a pressurized liquid phase reactor at 0.8 MPa and catalyzed by two commercial catalysts, i.e., β-zeolite and Amberlyst 16. The bRvp of etherified FCC gasoline was found to be lower than that of gasohol (20 vol.% ethanol), indicating that the gasoline from this process is more suitable than gasohol especially for the tropical zone or in summer. The decrease of bRvp was due to the consumptions of both ethanol and olefins. In case of β-zeolite catalyst, ethanol conversion was 36.3% while olefins content was decreased from 25.7 to 13.9 vol.%. However, as expected, etherified FCC gasoline gave slightly lower RON than gasohol. It was found that β-zeolite was a more suitable catalyst than Amberlyst 16 for the etherification of FCC gasoline with ethanol because it offered products with higher RON and higher ethanol conversion.     

近红外光谱法测定汽油中的芳烃含量

研究了采用近红外光谱测定汽油中芳烃含量的方法,通过汽油单体分析法获得汽油中芳烃的基础数据。在1000～2000nm波长范围内,应用傅立叶变换近红外光谱仪,交互检验偏最小二乘法对使用的近红外光谱数据进行优化,所得校正模型对训练集样品预测的相对平均误差为0.42%,相关系数为0.9696。对未知样品将近红外预测结果与GC的测定结果进行比较,相对平均误差为0.45%。作为一种快速分析技术,近红外光谱测定汽油中芳烃含量是简便可靠的方法。     

FCC汽油选择性深度加氢脱硫催化剂研究

采用固定床反应器,研究了催化剂载体原料、助剂以及螯合剂(M)对FCC汽油选择性加氢脱硫催化剂的活性及选择性影响,并对催化剂进行了200 h的稳定性试验.结果表明,采用大小孔拟薄水铝石混配原料和添加硼、钙、铈制备的载体,催化剂具有适宜的酸性中心和最佳的脱硫选择性;当M/Co+Mo=0.25 ～ 0.3时,选择性为最好,在200 h的试验运转过程中,具有较高的脱硫率和较低的烯烃饱和率,其活性稳定性良好.     

掺伪珍珠粉的近红外光谱定量鉴别方法

采用偏最小二乘法建立掺杂贝壳粉的珍珠粉的近红外光谱定量分析模型。以掺杂不同比例贝壳粉和珍珠粉作为掺伪样本,采集样本在4 000~10 000 cm-1范围内的近红外漫反射光谱,采用交叉验证和外部验证考察所建模型的可靠性。优化建模参数为:波数范围为4 100~7 500 cm-1;光谱预处理方法为二阶导数/矢量归一化(SNV)/Norris Derivative(5,5)滤波。所建定量分析模型的校正相关系数为0.999 7,校正均方差为0.708,交叉验证均方差为3.15。实验证明近红外光谱技术可用于掺伪珍珠粉的定量快速鉴别。     

中红外光谱法测定甲醇汽油中甲醇含量

利用IROX2000傅立叶红外光谱仪测定不同甲醇含量的甲醇汽油样品,与气相色谱方法进行了对比,找出了红外光谱法准确测定甲醇汽油中甲醇含量的范围,并验证其可靠性。实验证明,中红外光谱法具有分析快速、重复性好、分析成本低等优点。     

Determination of the Hydroxyl Value of Soybean Polyol by Attenuated Total Reflectance/Fourier Transform Infrared Spectroscopy

A rapid method for the quantitative determination of the hydroxyl value (OHV) of hydroxylated soybean oils by HATR/FTIR spectroscopy is described. Calibration standards were prepared by the formic acid/hydrogen peroxide method and OH values were determined by the official method of AOCS Tx 1a-66, covering an analytical range of 3.5–125 mg of KOH/g of sample. A partial least squares (PLS) calibration model for the prediction of the hydroxyl value (OHV) was developed based on eight different spectral subregions between 3,150 and 990 cm⁻¹ and combinations of them. On average, 36 samples were used for the modeling and 17 were used for external validation. The resulting calibration was linear over the analytical range and had a standard deviation of 2.334. Validation of the method was carried out by comparing the OHV of a series of hydroxylated soybean oils predicted by the PLS model to the values obtained by the AOCS standard method. A correlation coefficient of R ² = 0.9843 and RMSEC and RMSEP values of, respectively, 3.393 and 3.643 were obtained. After the calibration of the spectrometer, the OHV could be obtained in 2–3 min per sample, a major improvement over conventional wet chemical methods. The advantages of these methodologies are that they do not destroy the sample, have a lower cost, expedite the analysis and do not produce residues. Therefore, they may yield excellent results when used to quantify OHV of soybean polyols obtained by hydroxylation reaction.     

基于拉曼分析技术乙醇汽油辛烷值快速测定研究

车用乙醇汽油是通过在基础汽油中掺入一定比例的乙醇调和而成。在调和过程中由于其辛烷值波动较大,因此实时准确地检测汽油的辛烷值对生产高品质的汽油具有重要意义。基于拉曼分析技术汽油辛烷值在线监控系统能够适时监控乙醇汽油中各个组分变化,并给出对应的拉曼分析曲线;利用化学计量学方法结合Lambert-Beer定律,在检测到的数据和采用标准方法测得的属性数据之间建立关联分析模型,并用于乙醇汽油辛烷值的快速预测,指导实际调和过程。实践证明相对传统的检测手段,该系统具有测试速度快、分析时间短、检测费用低、经济效益高等特点。     

基于近红外光谱的汽油辛烷值在线分析仪

介绍自主开发研制的汽油辛烷值近红外(NIR)光谱在线分析仪。该分析仪包括NIR光谱在线测量、光谱预处理与实时建模等部分。对于原始的NIR光谱数据,采用多项式卷积算法进行光谱平滑、基线校正和标准归一化;通过模式分类与偏最小二乘进行实时建模。该分析仪已成功应用于某炼油厂重整反应器液相产物的辛烷值在线分析。     

Dynamic model-based batch process monitoring

An integrated framework consisting of a multivariate autoregressive (AR) model and multi-way principal component analysis (MPCA) is described for the monitoring of the performance of a batch process. After pre-processing the data, i.e., batch data unfolding, mean-centring and scaling, the data are then filtered using an AR model to remove the auto- and cross-correlation inherent within the pre-processed batch data. Model order is determined using Akaike information criterion and the model parameters are estimated through the application of partial least squares to attain a stable solution. MPCA is then applied to the residuals from the AR model. Three monitoring statistics are considered for the detection of the onset of process abnormalities in the batch process. The main advantage of the proposed approach is that it can monitor batch dynamics along the mean trajectory without the requirement to estimate future observed values. The proposed AR model-based approach is illustrated through its application to two polymerization processes. The case studies indicate that it gives better monitoring results in terms of sensitivity and time to fault detection than the approaches proposed by Nomikos and MacGregor [1994. Monitoring batch processes using multi-way principal components. A.I.Ch.E. Journal 40(8), 1361-1375] and Wold et al. [1998. Modelling and diagnostics of batch processes and analogous kinetic experiments. Chemometrics and Intelligent Laboratory Systems 44, 331-340].     

Determination of free fatty acids in crude palm oil and refined-bleached-deodorized palm olein using fourier transform infrared spectroscopy

A rapid direct Fourier transform infrared (FTIR) spectroscopic method using a 100 μ BaF₂ transmission cell was developed for the determination of free fatty acid (FFA) in crude palm oil (CPO) and refined-bleached-deodorized (RBD) palm olein, covering an analytical range of 3.0–6.5% and 0.07–0.6% FFA, respectively. The samples were prepared by hydrolyzing oil with enzyme in an incubator. The optimal calibration models were constructed based on partial least squares (PLS) analysis using the FTIR carboxyl region (C=O) from 1722 to 1690 cm⁻¹. The resulting PLS calibrations were linear over the range tested. The standard errors of calibration (SEC) obtained were 0.08% FFA for CPO with correlation coefficient (R ²) of 0.992 and 0.01% FFA for RBD palm olein with R ² of 0.994. The standard errors of performance (SEP) were 0.04% FFA for CPO with R ² of 0.998 and 0.006% FFA for RBD palm olein with R ² of 0.998, respectively. In terms of reproducibility (r) and accuracy (a), both FTIR and chemical methods showed comparable results. Because of its simpler and more rapid analysis, which is less than 2 min per sample, as well as the minimum use of solvents and labor, FTIR has an advantage over the wet chemical method.     

Microviscosity of an ion-conducting polymer probed by fluorescence depolarization and dielectric spectroscopy

The local segmental motions of polypropylene oxide melt with variable amounts of added LiClO₄ salt (0.3-2.2 mol% per repeat unit) were studied using dielectric relaxation spectroscopy and single photon counting methods after two-photon excitation of an unattached fluorescent dye, rhodamine123, embedded at low concentration within the polymer. The lithium ions serve as junctions between polymer chains and increase the bulk viscosity. The measured microviscosity contains information on the local environment of ClO₄⁻ ions.     

Probing electric field response of LC thermosets via time-resolved X-ray and dielectric spectroscopy

Curing of LCTs in an AC electric field was studied to understand the interplay between crosslink reaction and formation of a liquid crystalline (LC) phase and its effect on mechanical thermal properties on resulting thermosetting films. We show that dicyanate thermosetting monomers with ester functionality exhibit the ability to realign even after long curing times and allow poling of the LC director in resulting thermosetting films. To probe the details of the underlying process that leads to reorientation of the LC director model compounds were synthesized and their frequency and temperature dependent behavior under electric fields was studied. Curing reactions under electric fields show that the dual-frequency characteristics of the dicyanate mesogens behave very differently than epoxy thermosets. Size exclusion experiments reveal a prolonged gelation point in this system responsible for orientational switching even after long curing times. Finally, the ability to change orientation of the LC director allows tuning of modulus and thermal coefficient of expansion, making these thermoset films potential candidates for underfills, encapsulation materials and protective coatings for LC displays and active matrix substrates which require match in refractive index and mechanical/thermal properties.     

偏最小二乘-近红外光谱测定抚顺石油二厂汽油辛烷值

对来自抚顺石油二厂的汽油样品进行近红外光谱分析,使用偏最小二乘算法建立近红外谱图与辛烷值的关联模型.检测表明,用近红外光谱检测石油二厂汽油样品辛烷值的误差在标准方法规定的再现性要求之内,证明了用近红外光谱技术分析石油二厂汽油辛烷值的可行性.     

Determination of hydrogen content, gross heat of combustion, and net heat of combustion of diesel fuel using FTIR spectroscopy and multivariate calibration

The precise determination of the heat of combustion is of great importance for trading automotive diesel. The net heat of combustion (NHC) of fuel is related to the hydrogen elemental composition of fuel as obtained by elemental analysis. Heat of combustion expressed as gross heat of combustion (GHC) and net heat of combustion (NHC) have been predicted from data obtained by proximate analysis (density, ash, water and sulphur content) (ASTM D4868). GHC was obtained using bomb calorimetry (ASTM D240). The results of ASTM D4868 and ASTM D240 were found in good agreement. GHC and NHC fall within the relatively narrow range 45.24-46.08 and 41.91-43.27 MJ/kg, respectively. GHCs of tested diesel samples are, on average, about 7% greater than NHCs. The present paper also present a simple analytical method for determination of hydrogen content, GHC, and NHC of automotive diesel fuel using FTIR spectroscopy and partial-least squares calibration (PLS-1). PLS-1 had a high prediction power for prediction of hydrogen from FTIR spectra of diesel samples. The spectral ranges used in calibration were 400-670 and 2846-2970 cm⁻¹. On the other hand, classical least squares calibration (CLS) was found invalid for determination of hydrogen content in diesel. The results obtained by the proposed analytical method were almost to those obtained by ASTM D4868 and ASTM D240. PLS-1 method, offers a simple and reliable analytical method for quantification of hydrogen content in diesel samples without running expensive analysis like those carried out using carbon, hydrogen, and nitrogen (CHN) instruments.     

Relaxation dynamics and cold crystallization of poly(pentamethylene terephthalate) as revealed by dielectric spectroscopy

The relaxation dynamics of poly(pentamethylene terephthalate) has been investigated by means of dielectric spectroscopy. The sub-glass dynamics is characterized by the existence of a bimodal β process whose faster and slower components have been assigned to the relaxation of the bond between the ester oxygen and the aliphatic carbon and to the link between the aromatic ring carbon and the ester carbon, respectively. By comparison with other closely related aromatic polyesters it is shown that the faster component strongly depends on the amount of methylene groups while the slower one is not considerably affected by the nature of the glycol subunit. The changes in the α process associated to the segmental relaxation during cold crystallization reveal the formation of a rigid amorphous phase fraction. Combination of dielectric experiments with X-ray scattering ones suggests that during cold crystallization PPT crystal lamellae tend to fill the space homogeneously.