改质沥青的研制

本文扼要地介绍了太钢焦化厂创造热聚合—回配工艺研制改质沥青的情况。文中通过一些实例分析,揭示了沥青的BI、QI、软化点等主要质量指标与热聚合温度、时间的关系,以及BI与软化点之间的函数关系。为了比较,文中还介绍了国内外有关沥青粘结剂的质量标准和国内改质沥青生产的各种工艺路线。     

关于改质沥青粘结剂性质的研究

生产高功率和超高功率石墨电极,选择优质针状焦和改质沥青粘结剂是关键。近几年来,我国许多焦化厂已开始生产改质沥青,为炭素粘结剂的更新换代创造了条件。改质沥青粘结剂焙烧后残留更多的碳,减少浸渍次数,从而提高石墨制品的密度、强度和抗热震性能。下面就两种煤沥青粘结剂的性质对比予以分析讨论。 1.两种煤沥青的基本性质两种煤沥青的试样取自石家庄焦化厂,改质沥青是采用常压高温热聚法生产的,反应温度310～410℃,反应时间4～8小时。两种煤沥青的基本性质见表1。     

关于对石墨电极使用改质沥青技术指标的商榷

一、前言贵州铝厂引进工程,按国外配方选用103℃±3％(环球法)高软化点沥青,作为碳素材料的粘结剂,已由水城钢铁厂、贵阳铝镁设计院共同研制,经小型与半工业试验,试生产高软化点沥青三千余吨。1982年8月,中国有色金属工业总公司、贵州省冶金工业局在水城进行技术鉴定,并将新研制的粘结剂定名为“改质沥青”。与此同时,冶金部钢铁司根据鞍钢与澳商Kopper公司合作生产软化点105～125℃改质沥青的补偿贸易合同,1983年6月鞍钢改质沥青工程投产。 1984年5月,河北省石家庄焦化厂,宣化钢铁公司焦化厂与鞍山焦化耐火材料设计院共同研制改质沥青成功,并由河北省冶金工业厅     

乙烯焦油经AlCl_3催化改质制备高可熔性中间相沥青

研究了乙烯焦油用AlCl_3催化改质方法制备高可熔性中间相沥青的反应特性;求得了改质沥青和乙烯焦油沥青热缩聚反应速度常数和反应活化能等动力学参数,并对催化改质过程和中间相传化过程的组成和结构变化进行了分析。     

反应釜式改质沥青的生产

介绍了焦化厂近年来常压热聚合式改质沥青的生产经验,在完善改质沥青生产工艺、开发新产品、降低劳动强度和改善工作环境方面做了有益的探索和实践,并对改质沥青的生产提出了建议。     

焦油改质沥青质量的优化控制与提升

介绍了某焦化厂焦油改质沥青的生产及产品质量情况,分析了影响焦油改质沥青产品质量的主要因素,并提出了相应的控制办法。通过强化新旧焦油均匀混合、优化工艺参数、工艺改进等措施,改质沥青的综合合格率提高了近2%,对焦油改质沥青的稳定生产和质量提升起到了借鉴作用。     

改质沥青生产工艺的开发与应用

根据莱钢焦化厂改质沥青生产工艺的特点和存在问题,自主设计并采用了全自流改质沥青的生产工艺,实践结果表明,新生产工艺优化了反应釜加热炉炉体的结构,解决了造成改质沥青液下泵使用寿命较短的关键性技术难题,提高了生产开工周期,降低运行成本。     

改善改质沥青反应釜结焦的措施

改质沥青是煤焦油沥青经高温热聚反应加工而成的高附加值化工产品,用于制取电炉炼钢用的石墨电极、电解制铝的电极板及电极糊等碳素制品的粘结剂.由于其产量占煤焦油产品量的50%左右.因此.其产量及质量对煤焦油加工的整体效益具有决定性影响.我国是世界第三大产铝国,随着我国赋钢铁及铝产品结构的调整,高功率及超高功率电极的需求日益增加,加之碳素行业的飞速发展,对优质沥青的需求逐年增加.国外焦化行业由于受环保的限制而呈现萎缩,导致对改质沥青进口的增加.正由于改质沥青产品有着广阔的国内国际市场及较高的利润,近年来国内各大焦化厂相继增建了改质沥青生产装置,使产品的市场竞争日趋激烈.     

沥青质差热分析

在惰性气氛中,利用差热分析仪研究了不同添加剂改质煤沥青筑路油中沥青质的热失重情况。试验表明,沥青质失重与温度的关系符合一级反应动力学,由活化能可推测出沥青质是由不同分子量组成的复杂混合的。     

进一步提高煤沥青质量的探讨

炭素制品生产用粘结剂有两种功能，一是制品在混捏、成型过程中赋于糊料以一定的塑性，使其满足成型的要求；二是制品在焙烧过程中，在颗粒料之间形成炭膜粘结桥，将固体颗粒结合成一个整体，使其具有一定的机械强度。因此，粘结性能是沥青的一个十分重要的工艺性能，它是糊料塑性的决定性因素。煤焦油经管式护连续蒸馏生产煤沥青，是一种比较先进的方法。这种工艺生产的沥青软化点为SO－90t，属于中温沥青。近几年来研制成功的改质沥青，生产工艺有两种。一是以水城钢厂为主的加压热聚法工艺；另一种是石家庄焦化厂、宣钢焦化厂的常压热聚…     

煤沥青基中间相沥青的制备研究

以纯化的煤焦油沥青为原料,考察了热聚合温度和恒温时间对中间相沥青的收率、光学显微形态、软化点和族组成的影响.结果表明:反应温度在420℃,恒温5 h时得到了软化点为312℃的流线体型中间相沥青,其收率为79.1%;热聚合反应在相对较低的温度400℃,反应时间为10 h时形成了软化点为305℃、收率为81.4%的优质广域型可纺性中间相沥青.对该原料煤沥青而言,通过控制热聚合反应温度和恒温时间可以达到制备优质中间相的目的.     

A study of pitch-based precursors for general purpose carbon fibres

The isotropic phase isolated from a thermally treated coal-tar pitch was studied as a possible precursor for carbon fibres. Extraction with different solvents was performed in order to increase its softening point and so enable higher stabilisation temperatures to be used, with a significant reduction in time. The extraction conditions were selected studying the softening temperatures of the residues, the results of their thermogravimetric analysis and reactivity in air studied by means of differential scanning calorimetry. The residue obtained with a mixture of 40% acetone-60% acetonitrile was found to be the most suitable precursor for the fibres. The carbonised fibres showed a homogeneous surface and diameter, and had tensile properties comparable to other isotropic fibres described in the literature.     

沥青球的空气氧化稳定化反应特性研究

用 TGA、 DTG和 DTA法研究了石油沥青球和煤沥青球在空气中的热反应特性,研究了沥青球氧化稳定化的反应特点及其与沥青球组成与结构的关系。结果表明：石油沥青球由于与氧气的反应活性较强,更难于不熔化;增加萘含量和提高原沥青的软化点有利于沥青球的不熔化。     

Comparative studies of the modification of coal-tar pitch

Properties of coal-tar pitches modified by sulfur addition, air blowing, and nitrogen blowing were compared to find an appropriate method of preparing a matrix precursor for carbon/carbon (C/C) composites. Raw and modified pitches were characterized by softening point, thermal analysis (TGA), elemental analysis, solubility in toluene and quinoline, and gel permeation chromatography. Both sulfur addition and air blowing very effectively increased softening point and coke yield by dehydrogenative polymerization of pitch molecules. Air-blown pitch, however, had less thermal stability than the pitch with added sulfur and showed more weight loss at high temperatures. Property changes in nitrogen-blown pitch were mainly induced by eliminating volatile matter of low molecular weight. Sulfur addition is suggested to be the most promising method for preparing matrix precursor because it had the highest yield among those with similar softening points.     

添加硫沥青球不熔化机理的研究

为了阐明硫促进沥青球不熔化的原因,利用红外光谱（IR）、X－射线光电子能谱（XPS）、气相色谱（GC）及元素分析等方法研究了添加硫沥青球不熔化过程的机理,证明硫与沥青发生了反应,在沥青球内部形成了硫醇、硫酸、亚砜和砜等含硫官能团,促进了沥青分子的交联,提高了沥青的软化点．缩短了沥青球的不熔化时间。同时添加硫沥青球在不熔化过程中生成了H2S、COS、CS2等含硫组分。     

Synthesis of pitch materials from hydrogenation of anthracite

A Pennsylvania anthracite was ground, carefully dried and hydrotreated into materials with properties resembling those of pitches. The hydrotreatment was carried out using two hydrogen donors, 9,10-dihydroanthracene (DHA) and 1,2,3,4-tetrahydronaphthalene (THN), and two catalysts, molybdenum hexacarbonyl (Mo(CO)₆) and ammonium tetrathiomolybdate (ATTM). Due to the high reactivity at low temperatures, the degree of hydrogenation was probed in the temperature range 300, 350 and 400 °C. The optimum hydrogen donor, catalyst and hydrogenation temperature were 1,2,3,4-tetrahydronaphthalene, ammonium tetrathiomolybdate and 300 °C, respectively. This was reflected in an increase in the hydrogen-to-carbon atomic ratio (H/C) from 0.33 for the original anthracite to 0.42 for the pitch-like material from anthracite. Further, differential scanning calorimetry (DSC) showed that the anthracite-derived pitch material had a glass transition temperature (T_g) around 81.6 °C and softening point of 205.7 °C. This indicates that the softening behavior of the anthracite-derived pitch is similar to that of high-softening-point coal tar pitches. The anthracite-derived pitch material was evaluated by producing a small carbon body directly from the anthracite-derived pitch, and partial binding was observed.     

Preparation of mesophase-pitch-based carbon foams at low pressures

A simple method for preparing the mesophase-pitch-based carbon foams at low pressures through prolonging the soaking time in the preparation process of the mesophase pitch was disclosed. The physical properties, morphologies and the crystal structure of the as-obtained foams were investigated. Bulk density of the resultant carbon foams cover a range 0.514-0.624 g/cm³, under the preparation pressure range 0.5-2 MPa. The SEM micrographs revealed that the thermal shrinkage of the graphitized foams derived from the higher softening point mesophase pitch was less than that of the foam from the lower softening point; Optical micrographs showed that higher softening point mesophase pitch derived carbon foams exhibited better orientation and less microcracks in both junctions and ligaments; The XRD results revealed that higher softening point pitch derived graphitized foams exhibited smaller interlayer spacing and larger crystallite size. The properties of the carbon foam can be severely affected by the properties of the precursor, so it is critical to tailor the properties of the pitch precursor so as to obtain high performance and low cost products.     

精制沥青中间相热转化的研究

以2种精制沥青(LSP和HSP)为原料,通过常压热转化反应,研究了热转化过程中产物的QI和TI随反应时间的变化规律.分析表明,随着反应温度的升高和反应时间的延长,沥青的各向异性组分不断增加.其中LSP沥青生成的中间相小球大于HSP沥青生成的中间相小球.400℃恒温9h,LSP沥青的软化点达到242℃,HSP沥青的软化点达到220℃.     

Preparation of carbon fibre precursors from the pyrolysis and copyrolysis of Avgamasya asphaltite and Göynük oil shale: vacuum distillation and hexane extraction

Göynük oil shale (GOS) and Avgamasya asphaltite (AA) mixed in various ratios were used as raw materials for pitch precursors. Pure GOS and AA and their mixtures were pyrolysed at 550 °C and the resultant tars were vacuum distilled at 300 °C and 3 Torr for 60 min to produce pitch precursors. The pitch obtained in the highest yield was further modified by extraction with hexane. Structural characterisation by FTIR and ¹H and ¹³C NMR, and elemental analysis of the vacuum distillation pitches and the vacuum-distilled hexane-extracted pitch showed that vacuum distillation did not increase the softening point and toluene-insoluble (TI) content of the pitches. Further extraction with hexane removed significant amounts of aliphatic components from the pitch and increased the softening point to 136 °C. The vacuum-distilled, hexane-extracted pitch showed good spinnability into fibres of 15-20 μm diameter. The as-spun fibres were stabilised by nitric acid. The green fibres were pre-treated with air at low temperatures in order to complete stabilisation before the carbonisation process at 1000 °C. SEM images of the carbonised fibres showed surface defects due to pitch composition and/or insufficient stabilisation.     

改性沥青用作防水材料及铺路材料的工艺设计

本文阐述了利用废弃塑料(PE或PP)改性道路沥青材料和防水沥青材料的技术。分析了废弃塑料作为沥青的改性剂对沥青的软化点、脆性、针入度和延度等性能的影响。结果表明沥青的针入度和延度稍有降低，其软化点明显升高，拓宽了沥青的使用范围。