煤基沥青高温缩合反应的探索研究

以煤基中温沥青为原料,采用高温热缩合的方法制备高软化点沥青。主要研究了热缩合温度和热缩合时间对煤基沥青热缩合过程中软化点及喹啉不溶物含量的影响。实验结果表明:在一定的热缩合温度下,热缩合时间越长,得到的煤沥青的软化点和喹啉不溶物含量越高;在一定的热缩合时间下,热缩合温度越高,得到的沥青的软化点及喹啉不溶物的含量越高。     

基于8051单片机的沥青软化点控温系统设计

介绍在沥青软化点控温系统中,应用8051单片机控制一定的升温速率,实现沥青软化点测定过程中对温度的控制。控温系统中采用了PID控制理论,根据实际过程的温度变量,调整控温因子,使系统稳定在一定的升温速率上,满足JTJ052-2000《公路工程沥青及沥青混合料试验规程》中T0606-2000《沥青软化点试验》(环球法)的要求。     

基于DIP的沥青混合料车辙变形数值模拟

利用数字图像处理和有限元技术,生成沥青混合料非均质有限元模型,并分析沥青混合料各组分对其抗车辙能力的影响,从沥青混合料细观角度研究其永久变形规律,为沥青路面设计提供理论指导。结果表明,数值模拟得到的沥青混合料的车辙深度和车辙实验结果吻合较好,非均质有限元模型可对沥青混合料车辙深度进行预测;在各温度条件下提高集料的模量不能有效的提高沥青混合料的抗车辙能力;沥青混合料抗车辙能力增加速率随着沥青砂模量的增加呈现出先增加后减小的趋势;选用密级配的集料级配在软化点以上时可以较好的提高沥青混合料的抗车辙能力,低于软化点时影响不大。     

添加Bi2O3对SiO2-Al2O3-MgO系玻璃结构与性能的影响

采用传统熔体冷却法制备添加不同质量分数(0～3.0%)Bi_2O_3的SiO_2-Al_2O_3-MgO系玻璃,研究Bi_2O_3添加量对玻璃热稳定性、结构稳定性以及物理与力学性能的影响。结果表明:添加Bi_2O_3可有效降低玻璃的软化点;随着Bi_2O_3添加量的增加,玻璃析晶温度与玻璃化转变温度之差先增大后减小,光学带隙先减小后增大,说明玻璃的热稳定性和结构稳定性先提高后降低,同时玻璃的密度、弯曲强度、压缩强度和压缩模量也呈先增大后降低的趋势;当Bi2O3的质量分数为1.5%时,玻璃的结构稳定性、热稳定性、物理与力学性能最优异,此时玻璃析晶温度与玻璃化转变温度之差为244K,光学带隙为3.50eV,密度为2.67g·cm~(-3),弯曲强度为82.72 MPa,压缩强度为236.24MPa,压缩模量为110.06GPa。     

陕建SSD40型沥青碎石同步封层机

陕建SSD40型沥青碎石同步封层机主要功能是将粘结材料(沥青、改性沥青、乳化沥青或改性乳化沥青)和碎石同步撒铺在路面上,通过轮胎压路机或自然行车碾压形成单层沥青碎石磨耗层,主要用来防止水渗入路面,改善路面抗滑性以及填补小裂缝。可用作路面表面处理层、低等级公     

工艺参数对醇水均匀沉淀法制备纳米CeO2颗粒粒径的影响

在醇水混合体系中以乙醇为溶剂,六次甲基四胺(HMT)为缓释沉淀剂采用均匀沉淀法制备了纳米CeO2粉体,用透射电子显微镜(TEM)、X射线衍射仪(XRD)等方法对纳米颗粒进行了表征,研究了醇水比、反应温度、反应时间对纳米颗粒粒径的影响.结果表明:随着乙醇含量的增加,纳米颗粒粒径逐渐减小,随着反应温度的升高和反应时间的延长,纳米颗粒粒径增大.     

嵌段共聚物F68增韧改性PMMA的性能

采用嵌段共聚物F68对聚甲基丙烯酸甲酯(PMMA)进行原位增韧改性,研究了改性PMMA的力学性能、光学透明性和断面形貌,并探讨了其改性机理。结果表明:F68对PMMA有较好的增韧作用,随着F68含量的增加,改性PMMA的冲击强度不断增大,当F68的质量分数为20%时,其冲击强度提高了117.61%;改性PMMA的储能模量在玻璃化转度温度以上时随着F68含量的增加不断增大,而损耗因子的峰值温度逐渐降低;改性PMMA具有较好的光学透明性能,当F68的质量分数在20%以内时,改性PMMA透光率的降低小于2%。     

催化剂在浸渍增密C/C复合材料中的作用

在用煤沥青浸渍增密C/C复合材料时,如何提高煤沥青的残炭率,减少制造过程中闭气孔的形成,是降低复合材料制造成本的关键。本文采用在浸渍增密前,将预制体炭纤维浸泡在硝酸镍溶液中,然后烘干、浸渍的方法增密C/C复合材料。结果表明:由于在沥青炭化过程中,硝酸镍分解产生的N i具有催化作用,从而可使浸渍增密效果提高,制造过程中形成的闭气孔减少。在经过6次浸渍/炭化处理后,C/C复合材料的密度可达到1.70 g/cm3以上。     

季铵盐改性膨润土制备润滑脂的研究

以钙基膨润土为原料,采用季铵盐对其进行化改性,考察钠化改型、有机改性和处理工艺等对膨润土润滑脂性能的影响,分析有机膨润土层状结构与膨润土润滑脂性能的关系。结果表明,当有机改性剂十八烷基三甲基氯化铵的添加量为1.0CEC(阳离子交换容量),膨润土与水溶液、改性剂与水溶液的固液比为1∶10,Na_2CO_3的添加量为3%,磷酸添加量为5%,钠化反应温度为60℃,反应时间为30 min,有机改性反应温度为80℃,反应时间为60 min,每次添加800 m L水溶液,抽滤洗涤4次,干燥温度为80℃,粉碎过筛200目时,制备的膨润土性能较好,膨润土层间距变化与其制备润滑脂的稠度无直接关联。采用自制的改性膨润土制备的膨润土润滑脂,与市售的有机膨润土制备的膨润土润滑脂的性能相当,且具有更好的钢网分油性能。     

无机复合阻燃填料在软质聚氯乙烯中的应用研究

研究了以Al(OH)3、Mg(OH)2、煅烧高岭土、白炭黑为主要组分的无机复合阻燃填料(TFR1)填充软质聚氯乙烯(PVC)的阻燃性能、力学性能，并与其他无机阻燃填料进行了比较。结果表明：TFR1填充软质PVC的氧指数可达37.2％，阻燃性优于Al(OH)3、Mg(OH)2等阻燃填料；TFR1使PVC在较宽的温度范围内发生降解，失重速率降低，热失重减少，残炭量增加，有利于阻燃和消烟。经超细粉碎、表面改性和复配制备的TFR1在PVC基体中分散均匀，增强了与PVC的界面相互作用，从而使体系的力学性能明显提高。     

Microstructure and properties of pitch-based carbon composites

Pitches prepared in the laboratory by thermal treatment and air-blowing of a commercial coal-tar pitch were used as matrix precursors of carbon composites using granular petroleum coke, foundry coke, amorphous graphite and anthracite. Pitches were characterized by standard procedures (elemental analysis, softening point, solubility tests and carbon yield) and light microscopy (mesophase content). Pitch pyrolysis behaviour was monitored by thermogravimetric analysis and from the optical texture of cokes. Pitch wettability to the different carbons, at different temperatures, was also studied. Experimental conditions selected for the preparation of composites were based on pitch composition and properties. The main microstructural features of composites were determined by light microscopy and scanning electron microscopy. Composite properties were described in terms of their density, porosity and compressive strength, and related to composite microstructure and the characteristics of the precursors. Thermal treatment and air-blowing of pitch improved carbon composite structure and properties. The lowest porosities and best mechanical properties were observed in those composites obtained with the thermally treated pitches combined with foundry coke and anthracite.     

GC-MS在内蒙褐煤型煤块低温煤焦油成分分析中的应用

采用蒸馏技术和GC-MS技术,对内蒙褐煤型煤块低温炭化产品低温煤焦油馏分进行了定性定量分析,分析结果表明:内蒙褐煤型煤块的低温煤焦油中≤340℃的馏分占焦油重量的82.88%;>340℃的为沥青,占焦油重量的17.02%。从≤340℃的馏分中定性定量出139种化合物,其中,烃类占焦油的34.38%,以脂肪族烷烃为主,烯烃、环烷烃占少量;酚类占焦油的12.01%,集中在210℃前的馏分;芳烃类占焦油的16.73%,以甲基、乙基、丙基丁基等多烷基苯的取代衍生物为主,分布在各个馏分中,萘和甲基萘的衍生物以及蒽、菲芳烃主要集中在300℃前得馏分;含氧和含氮及杂环化合物分别占焦油的4.61%,0.52%,2.23%。通过研究为褐煤低温焦油的深加工利用提供了基础数据,同时提供了分析褐煤型煤块干馏产生的低温焦油的方法。     

Structures of insoluble carbon in tars and pitches

Primary or True QIs, and also the so-called ‘dirt’ were separated from seven tar sources available in Canada from four different steel companies, by filtering hot tar solution of quinoline and other good solvents. After washing with quinoline and acetone and drying, the filter cake was examined under scanning electron microscope (SEM) and analysed for inorganic impurities by wave length and energy dispersive X-ray spectrometers. A limited amount of work was carried out on a production pitch blend, utilizing optical microscopy. After the filtration process, the filtrates which represented the QI free tars were subjected to distillation at atmospheric pressure and various pitches were prepared with a softening point range of 70–100°C. The pitches were dissolved in quinoline and analysed for QIs. The small amount of QI from each pitch was extracted and dispersed with solvent onto a microscope slide. The samples then were subjected to SEM and in one case to optical microscope studies; the sizes and shapes of the QIs were determined and compared with the QIs originally found in the individual tars. Photographs have been taken during the scanning work to record findings which have been considered typical and demonstrative of the findings. In order to gather further information on the role of QI in tars and pitches, particle size distribution was determined of QI extracted from a tar and a production pitch by a Coulter Counter.     

改质沥青液下泵改造

介绍山西焦化焦油加工厂油库车间改质沥青液下泵通过技术改造提高产品使用性能,稳定生产,经济效益明显,并论述了设备改造的实用数据。     

Oxidative stabilization of C/C tow pregs studied by light microscopy

Tow pregs obtained from polyacrylonitrile-based carbon fibres and a commercial binder coal-tar pitch were stabilized by oxidation at 548, 588 and 623 K for periods ranging between 1 and 15 h. The microstructural changes involved in the stabilization of tow pregs on the carbonized laminates were studied by light microscopy. Under the conditions studied, the oxidative stabilization of tow pregs produced a significant increase in carbon yield. At the same time, the development of porosity on carbonization was avoided and the size of the optical texture was reduced. However, the extreme oxidation of pitch components at the edges of the carbonized laminate adversely affected pitch binding capability and the sinterizability of the laminates.     

The effect of the reinforcing carbon on the microstructure of pitch-based granular composites

Carbon composites were prepared with four pitches (a commercial impregnating coal‐tar pitch, two thermally treated pitches and an air‐blown pitch) and four granular carbons (anthracite, graphite, green petroleum coke and foundry coke). Granular carbon/pitch proportions were optimized for each composite and differed in the characteristics of the single components. Interactions of the pitch with the granular carbons during pyrolysis and their subsequent effects on the microstructure of the final composite were monitored by light microscopy. The results show that the light texture of the matrix and the porosity of the composite depend not only on the chemical composition of the pitch but also on the specific granular carbon used as reinforcing material. The same pitch may generate different light textures depending on the characteristics of the carbon. Composites from thermally treated pitches and graphite show highly ordered matrices orientated in the direction of graphite planes. Graphite particles seem to exert a huge influence on mesophase development during the pyrolysis of the treated pitches, affecting not only the orientation of the mesophase, but also reducing the rate of mesophase formation. On the other hand, when green petroleum coke is used with the thermally treated pitches, matrices show a small size light texture, due to the high reactivity of the pitch in the presence of this granular carbon. The porosity of the composites is controlled by both the pitch and the granular carbon.     

Effect of densification cycles on continuous friction behavior of carbon–carbon composites

This paper studies the continuous friction behavior of carbon–carbon composites (C/C) fabricated by the coal tar pitch densification process. In the densification process, different numbers of densification cycle are adopted to investigate the influence on physical properties, mechanical properties, microstructure and friction behavior. Experimental results indicate that open porosity decreases with the number of densification cycle. Both bulk density and flexural strength increase with the number of densification cycle. Apparent reduction in wear rate and average friction coefficient can be detected even if the lower densification cycle is adopted. As the number of densification cycle increases, C/C specimens exhibit the lower wear rate and smoother friction coefficient curves. Morphological observations show that the number of open pores for these materials decreases and they exhibit a denser morphology as the number of densification cycle increases. Furthermore, as the number of densification cycle increases, a smooth, adherent lubricating film is formed on the sliding surface. Therefore, the variation in average friction coefficient of specimens becomes smoother; in the meantime, the wear rate becomes lower.     

Structures and High Temperature Friction and Wear Performances of Ti/Ni-Doped Carbonaceous Mesophases

Metallic elements Ti and Ni were doped into the coal tar pitch-derived carbonaceous mesophase (CM) through mechanical alloying in a high-energy ball milling apparatus. The structures for the raw and Ti/Ni-doped carbonaceous mesophases were characterized by X-ray diffractometer. The friction and wear behavior of the Ti/Ni-doped CMs as lubricating additives at different applied loads and temperatures were investigated using a MMU-5G high temperature friction and wear tester. Worn morphologies of the lower 45^# carbon steel specimens were observed by scanning electron microscope (SEM). The carbonaceous substances on the worn surfaces were examined by Raman spectroscopic technique. The results have shown that the Ti/Ni-doped CM through mechanical alloying shows an increase in the crystallinity in comparison to that for the raw CM, implying a transition to the more ordered structures caused by the catalytic graphitization at lower temperatures due to the doped Ti/Ni. The Ti/Ni-doped CMs through mechanical alloying, when used as lubricating additives, displayed an obvious high temperature anti-friction and wear resistant effect, and the lager the applied load, the lower the friction coefficient and the wear severity. In addition, as the applied load increases, the carbonaceous substances on the worn surfaces show a rise in the ordered degree, and the corresponding microcrystalline planar size (L _a) for the carbonaceous substances becomes larger.     

Influence of matrix precursors on the microstructure and mechanical properties of C/C composites

The microstructure and properties of uni-directional pitch-based carbon-carbon composites are explained in terms of the chemical composition of pitch precursors. Pitches are characterized by standard procedures (elemental analysis, softening point and solubility tests), extrography which is a simple and rapid silica gel adsorption chromatographic technique, Fourier transform infra-red and gas chromatography of the toluene-soluble fraction. Pitch pyrolysis behaviour is monitored by hot-stage microscopy. The main microstructural features of uni-directional composites from pitches and commercial PAN-based carbon fibres are determined by light microscopy and scanning electron microscopy.