可溶性中间相沥青的制备研究

以净化沥青为原料 ,采用四氢萘高压氢化处理制取了氢化沥青 ,氢化沥青 H/ C原子比提高 14 %左右 ,最佳氢化温度为 4 2 0℃。以氢化沥青为原料 ,炭化热处理制备了中间相沥青 ,对炭化温度和恒温时间进行了优化选择 ,在 4 0 0℃下对氢化沥青炭化热处理 3h(升温速率为 2℃ / min) ,可制得喹啉可溶物 (QS)高达 85 %以上、TI含量为 71%和 β树脂含量为 5 8%的可溶性中间相沥青。     

炭阳极用煤沥青中间相的研究

选取热聚法、真空闪蒸法生产的煤沥青试样,全面分析了各项理化指标,重点研究了煤沥青的中间相含量及其黏度。试验结果表明,我国热聚法生产的煤沥青中间相含量高,为3.0%～6.9%,而真空闪蒸法生产的煤沥青几乎不含中间相。热聚法生产的煤沥青中主要指标甲苯不溶物、喹啉不溶物含量也较高,比国际上普遍采用的真空闪蒸法生产的煤沥青高出20%左右。煤沥青中喹啉不溶物及中间相的含量对黏度产生很大影响。在较低的温度条件下,我国热聚法煤沥青的黏度明显高于真空闪蒸法煤沥青。煤沥青的这些性质将对炭阳极的生产工艺参数及质量带来一定的影响。     

煤加氢液化残渣制备中间相沥青的研究

对神华煤加氢液化残渣依次使用正庚烷、甲苯、吡啶进行萃取,分别得到正庚烷可溶物(HS)、正庚烷不溶-甲苯可溶物(HI-TS)以及甲苯不溶-吡啶可溶物(TI-PS)3种可溶组分。分别以HI-TS及TI-PS两种组分为原料,采用直接热缩聚法,制备了中间相沥青(MP)。通过偏光显微镜、凝胶渗透色谱(GPC)等仪器分析手段对合成的中间相沥青进行了形貌及组成表征。实验结果表明:HI-TS组分在反应温度380℃,反应时间为6 h,TI-PS组分在反应温度380℃,反应时间4 h,均生成了光学组织结构好、中间相含量近100%的中间相沥青。     

两种不同原料中间相沥青分子结构的研究

采用偏光显微镜、族组成分析、红外光谱(FI-IR)、核磁共振(NMR)等研究手段,对两种不同中间相沥青FCC-MP(石油渣油热缩聚中间相沥青)和AR-MP(萘系催化合成中间相沥青)的组成结构进行研究,结果表明:100%中间相沥青在稠环芳烃区都有3个平行的红外特征峰(870,810,750 cm-1),且3个吸收峰的强度相近;FI-IR和NMR测试都表明,不同中间相沥青的支链比例差别很大,AR-MP分子上含有较多的甲基支链和环烷结构,非芳香碳占总碳原子的21%,FCC-MP分子上的支链和环烷比例较少,非芳香碳占总碳原子的14%,分子结构中支链和环烷结构有利于形成大融并体,降低软化点和熔融态黏度;根据1H-NMR和13C-NMR谱图计算出两种沥青吡啶可溶物(PS)的H、C分布数据和分子结构参数,并推导出两种中间相沥青PS组分的平均分子结构模型.     

低软化点可溶性中间相沥青的制备

将AlCl3(10%)催化萘在200℃恒温5 h制得萘的齐聚物,齐聚物主要为萘的三聚体,并含有四聚体和五聚体;然后通过加入不同比例的供氢剂十氢萘在340℃下恒温5 h热缩聚制得中间相沥青。结果表明:当十氢萘加入量为10%时,所得的沥青中间相含量高(100%),残炭率高(64.1%),软化点较低(190℃),可溶性较强(甲苯可溶组分含量为60.4%,吡啶可溶组分含量为80.2%)。     

压力对溶剂法脱除焦油沥青中固体颗粒物的影响

精制沥青是制备各种功能炭材料的前体,焦油沥青需要预处理脱除其中的固体颗粒物（称为喹啉不溶物,QI）以得到精制沥青,压力是脱除QI的重要条件。本文以煤焦油沥青和添加生物质沥青的混合沥青为原料,研究压力对溶剂法脱除固体颗粒物的影响,测试不同压力下精制沥青的QI含量及产率,利用纳米粒度分析仪、扫描电子显微镜和高温黏度测定仪对QI颗粒形貌、粒度及脱除体系黏度进行表征和测定,分析压力对固体颗粒物絮凝沉降的影响规律。研究结果表明,增加压力对沥青收率升高有明显影响,使精制煤焦油沥青的收率由常压的64.6%（质量分数）提升至1MPa时的84.3%（质量分数）,精制沥青的QI含量维持在0.06%~0.1%（质量分数）之间。添加15%生物质沥青的混合沥青,产率则由常压时的55.7%（质量分数）提升至1MPa时的72.5%（质量分数）。压力对精制沥青的QI含量影响较小,压力增大,溶剂对沥青组分尤其是重质组分的溶解能力增强,使精制沥青产率升高。较高压力也使体系的黏度略微增大,造成部分QI颗粒沉降困难,不过影响较小。中间相沥青制备的结果表明,精制沥青可以制备出具有流域型结构的中间相沥青,添加生物质沥青更好地改进了流域型的显微结构。     

用丁苯橡胶改性乙烯焦油制备中间相沥青

用丁苯橡胶(SBR)与乙烯焦油在430℃、常压及惰性气体保护下进行共炭化,制备出各向异性中间相沥青,并对其进行了分析和表征.结果表明,由SBR改性乙烯焦油制得的中间相沥青与乙烯焦油直接炭化制得的中间相沥青相比,有序度高,黏度低,口树脂含量高,且具流线广域性组织结构.     

沥青－重油共炭化制取中间相沥青基炭纤维初探

利用工业重油三线芳烃和煤焦油沥青共炭化改善沥青的炭化性质，调制可纺性中间相沥青。本文主要考察了共炭化反应条件对沥青改性的影响，不同热缩聚条件与所得中间相沥青的软化点，光学各向异性含量和可纺性的关系，并对中间相沥青进行初步熔纺及后处理，制得强度较高的炭纤维，讨论了由此途径制取高性能沥青基炭纤维的工艺特点。     

煤焦油沥青非等温中间相转化及其动力学研究

通过添加不同焦粉含量的煤焦油沥青非等温中间相转化动力学研究,测定了中间相转化动力学参数,并借助偏光显微镜对热转化残留物的光学显微结构进行了观察。结果表明,煤焦油沥青中间相转化属于一级动力学反应,在400~500℃其表观活化能为222.6~241.8 kJ/mol。添加焦粉降低了中间相转化活化能,加快了中间相转化速率,缩短了中间相转化特征温度区间,导致热转化残留物中形成大量镶嵌结构,不利于针状焦光学显微结构生成。随着焦粉添加量的增加,这种不利影响加剧。     

中间相沥青制备有序结构炭前驱体的研究

以低QI含量的煤沥青为原料,通过控制热聚合时间得到不同甲苯可溶物(TS)含量的热塑性沥青中间相预聚体,并以中间相预聚体为原料考察了热态成型对中间相有序生长的影响.结果表明,在室温～600 ℃,成型压力为3.12 MPa,中间相预聚体中TS含量为10.7%～26.3%(质量分数)时,通过热态成型能够得到有序柱状初坯体.通过偏光显微镜观察,其中间相液晶分子沿垂直于模压压力方向排列成纤维状长程有序结构,经1 100 ℃炭化后测得炭前驱体样品的电阻率纵向为1.78 Ω·cm～2.99 Ω·cm,横向为0.83 Ω·cm～1.41 Ω·cm.由此所得有序炭前驱体具有显著的择优取向结构,属于易石墨化碳,为制备高导热炭材料奠定良好基础.     

采用改质沥青与中温沥青生产石墨电极对比

随着我国电炉炼钢的发展,对石墨电极的质量提出了更高的要求。煤沥青作为生产石墨电极的黏结剂,很大程度上影响着石墨电极的质量。目前国内石墨电极生产厂家一部分采用中温沥青,一部分采用改质沥青,逐步摆脱了传统的黏结剂与浸渍剂     

Carbonization of pitch

An overview is presented of the many factors which influence the process of carbonization of pitch and hence the properties of pitch cokes. The controlling factors include type of starting material, the industrial process of carbonization, the role of quinoline-insoluble material and carbonization conditions. Several coke parameters are studied and related to the carbonization process by multiple regression analysis. Kinetic data are presented together with a schematic model of coke formation.     

Thermooxidation of coal tar pitch with the return of pitch distillates

The thermooxidation of moderate-temperature coal tar pitch with the return of pitch distillates is investigated, in conditions such that high-temperature grade-C pitch is obtained. Gas-liquid chromatography shows that the content of polycyclic aromatic hydrocarbons included in the list published by the United States Environmental Protection Agency (EPA) is not significantly different in the pitch samples before and after oxidation.     

浸渍剂沥青和黏结剂沥青渗透性对比研究

选择两类具有相近流变性能的黏结剂沥青和浸渍剂沥青,模拟炭材料的微孔分布测定了两类沥青的渗透率,对比研究了浸渍剂沥青和黏结剂沥青的渗透性能差异。结果表明,浸渍剂沥青的渗透性能远优于黏结剂沥青,浸渍剂沥青的渗透率为黏结剂沥青相应值的3.54~22.13倍,两类煤沥青的渗透性差异是由于其QI含量不同造成的,浸渍剂沥青极低的QI含量(0.2%以下)大大降低了煤沥青向多孔滤材中的渗透阻力,为提高浸渍效果创造了有利条件。     

A thermoanalytical study of the co-pyrolysis of coal-tar pitch and petroleum pitch

Four pitch blends were prepared at laboratory scale by mixing a coal-tar pitch and a petroleum pitch in several proportions (CTP:PP 85:15, 70:30, 55:45 and 40:60). Single pitches and blends were characterized by standard procedures, infrared spectroscopy and size exclusion chromatography. Pyrolysis behaviour and interactions between the two pitches in the blends were studied by thermogravimetric analysis (TG/DTG) and differential scanning calorimetry (DSC). The results show that blending does not alter the composition of pitches. However, the TG/DTG curves reveal that coal-tar pitch and petroleum pitch interact actively during pyrolysis, modifying the temperature of initial weight loss and the temperature of the maximum rate of weight loss. Primary quinoline-insoluble particles present in coal-tar pitch and transferable hydrogen seem to be the main factors responsible for these modifications. The DSC curves show that the presence of coal-tar pitch in the blends reduces the reactivity of the petroleum pitch and shifts the exothermic peaks observed at the temperature of the cracking/polymerization reactions (>400 °C) to lower temperatures.     

Enhanced oxidation performance of pitch fibers formed from a heterogeneous pitch blend

The oxidation performance of heterogeneous pitch fibers formed by blending a coal tar-derived isotropic pitch (IPc) and a naphthalene-derived mesophase pitch (MPn) was studied. The role of IPc in affecting the oxidation performance of such heterogeneous fibers was illustrated. The IPc spherical domains distributed in the MPn matrix facilitate the reduction of oxidization time and the decrease of the gradient of oxygen distribution. As such, the MPn/IPc blends have been demonstrated to be a feasible approach for reducing the oxidation difficulties in producing large diameter carbon fibers. Further improvement on the oxidation efficiency and the suppression of deep stabilization in large diameter pitch fibers were observed, when the blend precursors were oxidized in pure oxygen atmosphere.     

High-temperature synthesis of pitch

The heat treatment of the anthracene fraction of coal tar under pressure is considered. In the production of synthetic pitch, the duration of the process is varied from 10 to 80 min, at a temperature of 500°C and a pressure of 3 MPa. Kinetic data for the formation of γ and α₁ fractions show that the polycondensation of the γ fraction is of second order, while the formation of the α₁ fraction is of zero order. Pitch obtained with holding for 10–40 min does not contain the α₁ fraction. Extending the process beyond 30 min does not affect the removal of heteroatoms. IR spectroscopic data indicate that dealkylation predominates for the first 40 min. Then the process slows, and compaction develops.     

沥青热解模型

沥青是制备炭材料的重要前驱体之一,深入理解其炭化行为有助于控制炭产品性能。采用峰值分离的方法对沥青的DTG曲线进行分解,得到3个部分交叠的温度区间,用三阶段连续伪组分反应动力学模型拟合发现,3个阶段均是一级反应。并对2.5 K/m in至10 K/m in加热速率下的热质量损失曲线进行计算,结果与实验数据吻合良好。对炭化过程中挥发分形成的气泡的生长动力学进行理论计算,结果表明,气泡的直径随温度升高单调增加,沥青的热解质量损失率是气泡生长的控制因素。相同热解温度下,气泡外围的液体径向速度随加热速率的增加而成倍增加,因此加热速率应该遵循"两头快,中间慢"的原则。