CO2管线泄漏扩散小尺度实验研究

CO₂气体综合开发和利用过程中涉及很多安全问题,为了研究CO₂作为典型重质气体从输送管线泄漏后的扩散规律,在综述重气扩散实验的基础上设计了CO₂管线泄漏扩散缩比例实验;通过幂函数拟合得到监测点峰值浓度曲线,并据此确定了生产现场的安全距离;根据危险气体非正常排放模型对实验进行了理论预测,结果与实验值进行了对比。结果表明小风条件下,当以950 m³·h^-1初始流量释放20 min左右的CO₂时,现场安全距离可设为46 m,而当初始流量为6300 m³·h^-1时,现场安全距离为160 m;实验值和理论预测值的偏差最小为-3.0%,最大为28.1%。经分析可知CO₂管线泄漏近源区一定距离内主要靠射流动能扩散,其后范围主要受浓度梯度的影响,危险气体非正常排放模型可较准确地预测近源区的扩散情况;安全距离与泄放流量基本呈指数关系。     

输气站场脱硫装置H2S泄漏扩散规律及后果研究

为定量分析不同工况条件下H₂S泄漏扩散的影响规律,在分析H₂S气体危险性的基础上,采用DNV PHAST软件模拟不同泄漏孔径、扩散时间和气象条件对浓度分布的影响,进而考察毒性、喷射火和蒸气云爆炸带来的危险后果。结果表明,泄漏孔径和扩散时间与下风距离、云团宽度和云团高度等参数呈正比,大气稳定度越低、风速越大,越有利于气体扩散;H₂S的主要危害为中毒,其引发室外致死率为0.1%、1%、10%和99%时的下风距离分别为652.6 m、574.7 m、482.1 m、216.7 m。研究结果可为有毒气体的泄漏风险防控提供实际参考。     

液氯泄漏扩散及其危险范围的预测

基于传质学、流体力学、大气扩散学的基本原理,以某生产二氯丙烷的化工企业的液氯储罐泄漏为例,假设液氯储罐发生瞬时泄漏,利用气体湍流扩散微分方程,对泄漏气体的扩散行为进行建模和简化,建立了相对应的泄漏气体扩散浓度分布模型。然后通过计算大气稳定度以及扩散参数,求得氯气云团扩散形成的中毒危险区范围和氯气云团消散失去毒害作用需要在下风向扩散的距离,计算结果可对有毒有害气体泄漏后预测扩散危险区范围提供相关的依据。     

有毒有害气体危害阈值的探讨

近年来,化工园区突发大气环境污染事故频发,为有效评价突发大气污染事故的影响程度,急需建立恰当的有毒有害气体危害阈值体系。本研究通过对比分析IDLH、LC50、AEGLs、ERPGs、TEELs、PACs等国内外有毒有害气体危害阈值数据的由来、意义及适用条件,建议在进行有毒有害气体泄漏危害事件预测和后果分析中,有毒有害气体危害阈值建议采用的优先顺序为:AEGLsPACsERPGsTEELsIDLHLC50。     

化学危险性气体泄漏扩散模拟及其影响因素

分析了描述易燃易爆及有毒有害气体泄漏扩散过程的数学模型 ,包括Gaussian模型、Gaussian轨迹烟云模型、BM模型、Sutton模型及FEM3模型。重点介绍了目前广泛使用的Gaussian模型及Gaussian轨迹烟云模型。针对事故泄漏扩散过程的复杂性 ,详细讨论了气象条件及地形条件对危险性物质泄漏扩散过程的影响 ,此外还对不确定参数的选取进行了探讨。     

架空天然气管道泄漏扩散过程特性分析

在天然气管道集输过程中,由于管道老化、腐蚀等因素引起的泄漏事故时有发生,会引起穿孔泄漏后的天然气扩散,可能会引发火灾、中毒或爆炸。因此,进行架空天然气管道泄漏扩散过程的影响因素模拟研究及分析,对天然气管道输送安全运营和保障人生财产安全意义重大。文章建立了架空天然气管道在迎风坡和背风坡处发生泄漏扩散过程的物理模型,并利用CFD软件对架空天然气管道泄漏后的甲烷气体扩散过程进行了数值模拟。结果表明：泄漏的甲烷气体扩散范围和速度非常大,在泄漏时间300S时泄漏距离已经达到40m,并在40m处形成高浓度的甲烷气团;泄漏点在背风坡时,山坡附近形成高浓度甲烷气团。     

采用高斯模型分析输气管道泄漏后气体的扩散

在深入分析输气管道泄露气体扩散的基础上,根据天然气扩散本身的特征和研究问题的需要,采用高斯模型确定了泄漏源有效高度,天然气扩散系数,高度与风速的关系。指出：泄漏源抬升高度与扩散气体的初始速度和方向、初始温度、泄漏口直径、环境风速的关系;扩散系数的大小与大气湍流结构、离地面高度、地面粗糙度、泄漏持续时间、抽样时间间隔、风速以及离开泄漏源的距离等因数的关系;风压高度变化系数和高度的函数关系。     

N_2O_4野外转注中泄漏扩散的数值模拟分析

针对四氧化二氮(N_2O_4)运输转注发生泄漏可能造成的危害,采用数值模拟方法,建立N_2O_4野外转注过程中泄漏扩散模型,计算分析了气体扩散形成的有害气云覆盖区域变化情况,下风向不同位置有毒气体浓度变化情况。结果表明:推进剂泄漏扩散受风力作用影响较大,气体向下风向扩散,气云覆盖面积随着扩散距离的增大而增大,气云变得更稀薄,气云中N_2O_4的浓度降低;连续性泄漏时,固定位置处气体的浓度能达到一个稳定值,一个位置与气体泄漏源越远,该位置气体浓度达到稳定值所需时间越长。     

基于高斯烟羽模型的山区含硫天然气泄漏扩散研究

为了预测含硫天然气泄漏后危险气体的扩散浓度和地形对气体扩散的影响,以高斯烟羽模型为基础,结合当地的实际环境,开展了含硫天然气在不同地形条件下连续泄漏的模型分析,并利用MATLAB对该气体的扩散进行计算,得出了相应的下风向气体的扩散浓度及其危害距离。结果表明:不同的地形条件下,含硫天然气扩散的距离和浓度不同。在下降地形中,气体浓度不会太高,但是泄漏范围较大;在上升地形中,泄漏气体易于在山体前聚集,少数气体绕山泄漏,但浓度急剧降低;在先下降后上升地形中,泄漏气体易于在下降地形和山体链接处聚集。     

泄漏气体扩散模型的研究与应用

通过对泄漏源模式及泄漏影响因素的分析,以湍流扩散微分方程为基础,对泄漏气体扩散行为模型化,得到有界和无界的烟团和烟羽模型,并进行了实例分析。扩散模式的研究可以确定事故影响范围、危害程度,为事故应急救援,人员撤离等提供参考。     

Nanomechanical mapping of glass fiber reinforced polymer composites using atomic force acoustic microscopy

In this work, a dual‐frequency resonance tracking (DFRT) method was applied on atomic force acoustic microscopy (AFAM) and high‐resolution, quantitative nanomechanical mapping of a glass fiber–reinforced polymer composites (GFRP) was realized. Results show that even using the single‐frequency AFAM, the fiber, and epoxy can give very good contrast in amplitude images. The modulus mapping result on GFRP by DFRT AFAM was compared with that by dynamic nanoindentation, and it is found that DFRT AFAM can map the elastic modulus with high spatial resolution and more reliable results. The interface of GFRP was especially investigated using a 2 μm × 2 μm scanning area. Finite element analysis was implemented to investigate the effect of tip radius and the applied pressing force on the interface measurement using a sharp “interface”. By setting a linear‐modulus‐varied interface with finite width in finite element analysis (FEA), similar comparison between FEA and AFAM experimental results was also implemented. The average interface width is determined to be 476 nm based on the high‐resolution modulus image, indicating that AFAM is a powerful method for nanoscale interface characterization. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39800.     

A novel Bayesian inference soft sensor for real‐time statistic learning modeling for industrial polypropylene melt index prediction

A novel real‐time soft sensor based on a sparse Bayesian probabilistic inference framework is proposed for the prediction of melt index in industrial polypropylene process. The Bayesian framework consists of a relevance vector machine for predicting melt index and a particle filtering algorithm for soft sensor optimization. An online correcting strategy is also developed for improving the performance of real‐time melt index prediction. The method takes advantages of the probabilistic inference and using prior statistical knowledge of polymerization process. Developed soft sensors are validated with ten public databases from UCI machine learning repository and real data from industrial polypropylene process. Experimental results indicate the effectiveness of proposed method and show the improvement in both prediction precision and generalization capability compared with the reported models in literatures. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45384.     

对机械设备设计研发过程的讨论

本文对机械设备设计研发过程的基本步骤、工作方法及需要引起注意的问题进行了较详细的论述,并对机械设备设计研发工作的开展提出了一些建议.     

Generalizing solubility parameter theory to apply to one‐ and two‐dimensional solutes and to incorporate dipolar interactions

Hildebrand and Hansen solubility parameters are commonly used to identify suitable solvents for the dispersion or dissolution of a range of solutes, from small molecules to graphene. This practice is based on a number of equations, which predict the enthalpy of mixing to be minimized when the solubility parameters of solvent and solute match. However, such equations have only been rigorously derived for mixtures of small molecules, which interact only via dispersive forces. Herein, we derive a general expression for the enthalpy of mixing in terms of the dimensionality of the solute, where small molecules are considered zero‐dimensional, materials such as polymers or nanotubes are one‐dimensional (1D) and platelets such as graphene are two‐dimensional (2D). We explicitly include contributions due to dispersive, dipole–dipole, and dipole‐induced dipole interactions. We find equations very similar to those of Hildebrand and Hansen so long as the solubility parameters of the solute are defined in a manner which reflects their dimensionality. In addition, the equations for 1D and 2D systems are equivalent to known expressions for the enthalpy of mixing of rods and platelets, respectively, as a function of surface energy. This agreement between our expressions and those commonly used shows that the concept of solubility parameters can be rigorously applied to extended solutes such as polymers, nanotubes, and graphene. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

涂料研究开发新进展及关键科学与技术问题

阐述了近年来国内外涂料的研究开发现状,包括:利用新的树脂合成方法获得新的成膜物;直接引入无机纳米粒子以改善涂层性能;表面微纳结构构建以获得功能涂层等;提出了未来涂料技术的发展趋势,包括:环保化和健康化;通用涂层的高性能化;多功能化和智能化等;和需要突破的关键科学与技术问题。当企业发展到一定阶段和规模后,要加强科研开发的投入,加强产学研合作,加强基础研究,要敢于开发国外没有的技术和产品,敢于领先国外技术,才能真正成为涂料强国。     

TiO2‐Oligoaldaramide nanocomposites as efficient core‐shell systems for wood preservation

Homogeneous core‐shell systems were obtained with a growth, in controlled steps, of several oligoamides on TiO₂ nanoparticles. Derivatives of natural compounds, such as l ‐tartaric acid and α,α′‐trehalose, were used as diesters in the polycondensation reactions with ethylenediamine. TiO₂ anatase was chosen because of its high photo‐activity and its antimicrobial activity. The TiO₂ nanoparticles had been previously activated then functionalized using two different coupling agents, and finally, the TiO₂‐oligoamide nanocomposites were synthesized using two synthetic pathways. The final products were characterized by ¹H NMR, ¹³C NMR, FT‐IR, and transmission electron microscope. These nanocomposites can show improved properties in comparison with the single components (TiO₂ nanoparticles or oligoamides), which are useful in many fields, such as antimicrobial coatings for surfaces in cultural heritage conservation. A nanocomposite (TiO₂‐polyethylenetartaramide) was used for applicative studies, and it has shown a good efficacy against fungal attack by Trametes versicolor on wood specimens (Fagus sylvatica). © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42047.     

Synthesis and properties of cross‐linked polymers from epoxidized rubber seed oil and triethylenetetramine

A series of epoxidized oils were prepared from rubber seed, soybean, jatropha, palm, and coconut oils. The epoxy content varied from 0.03 to 7.4 wt %, in accordance with the degree of unsaturation of the oils (lowest for coconut, highest for rubber seed oil). Bulk polymerization/curing of the epoxidized oils with triethylenetetramine (in the absence of a catalyst) was carried out in a batch setup (1 : 1 molar ratio of epoxide to primary amine groups, 100°C, 100 rpm, 30 min) followed by casting of the mixture in a steel mold (180°C, 200 bar, 21 h) and this resulted in cross‐linked resins. The effect of relevant pressing conditions such as time, temperature, pressure, and molar ratio of the epoxide and primary amine groups was investigated and modeled using multivariable nonlinear regression. Good agreement between experimental data and model were obtained. The rubber seed oil‐derived polymer has a T_g of 11.1°C, a tensile strength of 1.72 MPa, and strain at break of 182%. These values are slightly higher than for commercial epoxidized soybean oil (T_g of 6.9°C, tensile strength of 1.11 MPa, and strain at break of 145.7%). However, the comparison highlights the potential for these novel resins to be used at industrial/commercial level. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42591.     

Preparation and testing of Nafion/titanium dioxide nanocomposite membrane electrode assembly by ultrasonic coating technique

Membrane electrode assemblies with Nafion/nanosize titanium dioxide (TiO₂) composite membranes were manufactured with a novel ultrasonic‐spray technique (UST) and tested in proton exchange membrane fuel cell (PEMFC). The structures of the membranes were investigated by scanning electron microscopy (SEM), X‐ray diffraction (XRD), and thermogravimetric analysis. The composite membranes gained good thermal resistance with insertion of TiO₂. The SEM and XRD techniques have proved the uniform and homogeneous distribution of TiO₂ and the consequent enhancement of crystalline character of these membranes. The existence of nanometer size TiO₂ has improved the thermal resistance, water uptake, and proton conductivity of composite membranes. Gas diffusion electrodes were fabricated by UST. Catalyst loading was 0.4 (mg Pt) cm^?2 for both anode and cathode sides. The membranes were tested in a single cell with a 5 cm² active area operating at the temperature range of 70°C to 110°C and in humidified under 50% relative humidity (RH) conditions. Single PEMFC tests performed at different operating temperatures indicated that Nafion/TiO₂ composite membrane is more stable and also performed better than Nafion membranes. The results show that Nafion/TiO₂ is a promising membrane material for possible use in PEMFC at higher temperature. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40541.     

Poly(butylene succinate)/layered double hydroxide bionanocomposites: Relationships between chemical structure of LDH anion,delamination strategy,and final properties

A series of poly(butylene succinate) (PBS) containing organo‐modified layered double hydroxide (LDH) are prepared by melt compounding and by in situ polymerization of succinic ester and 1,4‐butanediol. Various LDHs intercalated with renewable organic anions are used. More specifically, lauryl sulfate, stearate, succinate, adipate, sebacate, citrate, and ricinoleate ions are used as LDHs organo‐modifiers. The thermal, rheological, and dynamic mechanical properties of the samples are investigated. The results reveal a general mechanical reinforcement imparted by the clays. Significant changes are observed for the in situ polymerized nanocomposites, especially for LDH stearate which improves the properties of PBS nanostructure, whereas very few differences are observed for the other samples. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1931–1940, 2013     

Lipid Composition,Natural Antioxidants and Physicochemical Characteristics in Liver Oil from Rajiforms from the Gulf of Mexico

Lipid composition by class, fatty acids, natural antioxidants (carotenes, tocopherols) and physicochemical characteristics of liver oil from three commercial rays, Rhinoptera bonasus (Chucha), Aetobatus narinari (Pinta) and Dasyatis americana (Bala) from the Gulf of Mexico were analyzed. Liver oil yield for R. bonasus, A. narinari and D. americana were of 43.04, 41.2 and 38.2% (wet weight), respectively. Triacylglycerols were the most abundant lipid by class in R. bonasus (68.9%), A. narinari (85.9%) and D. americana (81.6%), while sterols esters, sterols, di- and monoacylglycerides, polar lipids and wax esters were found in minor proportions. Species showed similar carotenes concentration, 8.7, 12.8 and 8.0 μg/g for R. bonasus, A. narinari and D. americana, respectively. α-tocopherol concentration was higher (p < 0.05) for A. narinari (46.7 mg/100 g) than for R. bonasus (21.0 mg/100 g) and D. americana (13.7 mg/100 g). Omega-3 polyunsaturated fatty acids in R. bonasus were high with docosahexaenoic acid (12.1%) in a higher proportion than eicosapentaenoic acid (7%).