HMX基浇注PBX药浆表观黏度的实验研究

采用旋转黏度计分别测定了不同温度、分散剂加入量、炸药颗粒级配时HMX基浇注PBX药浆的表观黏度,通过流动曲线绘制和数据拟合方法考察了这些因素对表观黏度的影响。结果表明,随着温度升高,药浆的表观黏度降低,流动指数变大,流变特性更接近牛顿流体;卵磷脂的加入会影响药浆的流变特性,且有助于降低药浆的表观黏度,但其加入量存在一个最佳值;在药浆固相含量一定的情况下,其表观黏度在实验测定范围内随着细颗粒含量的增加而增大。     

油煤浆表观黏度测定方法研究

为建立油煤浆表观黏度测定标准,实现油煤浆表观黏度的准确测量,研究了多种煤液化油煤浆在不同条件下的流变行为,考察了剪切速率、测量温度、样品放置时间、读数开始时间等因素对油煤浆表观黏度测值的影响,并确定了油煤浆表观黏度测定方法的精密度。结果表明:测定油煤浆表观黏度的最佳条件为:剪切速率100 s-1,测量温度60℃,油煤浆取样后应立即进行黏度测定,启动旋转黏度计后,第11 min开始记录读数,每隔10 s记录一次,共计30次,以测定结果的平均值为样品黏度值,修约到整数位报出。规定油煤浆表观黏度测定方法的重复性限r=0.13η100 s-1-4.30,由于试验仪器条件的限制,未对再现性做出说明。     

粒度级配对神华煤成浆特性影响的试验研究

为了研究粒度级配对神华煤成浆特性的影响,通过筛分和干法调浆,探讨了不同粒度分布煤粉的成浆性,结果表明:在添加剂用量为0.3%(干基/干煤)时,具有连续级配特征的原始煤粉可制备出质量分数为61%的煤浆;利用筛分法,分别去除原始煤粉中0.045 mm以下、0.045 mm^0.15 mm、0.15 mm^0.3 mm和0.045 mm^0.3 mm部分,得到4种具有不连续级配特征的样品,其所制煤浆流变性发生了较大变化,其中去除0.045 mm^0.3 mm部分的样品的成浆质量分数提高了3个百分点,在黏度符合要求的前提下流动性大幅提高;连续级配和非连续级配的煤浆均存在黏度与流动性不统一的现象,当级配中粗细颗粒粒径差较大且细颗粒含量达到一定值时,这种现象更加明显。采用粒度级配技术制浆,其细颗粒含量存在一个合理的区间。     

直径间隙法制水煤浆级配技术研究

采用双珠级配与三珠级配模型,探讨了球料比、研磨时间、温度、入料尺寸和研磨速度对灵武煤制水煤浆成浆性的影响,分别采用干法配浆与湿法配浆的方法进行实验,利用DV-1+PRO数字式黏度计和Rise-2008型激光粒度分析仪对配置浆料的黏度和粒度进行测试.结果表明,当入料尺寸<1mm,球料比为6∶1,研磨速度为72r/min时,水煤浆的浓度可以达到68%.10#自制添加剂的使用可以获得性能稳定的水煤浆浆体.     

不同尾砂级配料浆的优化配比试验研究

为探求某矿尾砂级配料浆的最优配比,调整尾砂原样的粒径组成,并通过三轴剪切试验得到各级配试样的剪切变形、强度特性规律,设计正交试验,分别得到级配组成、料浆质量分数、灰砂比对泌水率、坍落度、抗压强度等的影响关系。结果表明:调整尾砂级配后,各级配试样变形规律大致相同,但峰值强度和残余强度得到明显改善;3个因素对试样泌水率、抗压强度的敏感性排序为:料浆质量分数灰砂比级配,而对坍落度的敏感性排序为:灰砂比级配料浆质量分数。考虑矿体的深部力学环境和经济因素,最终确定该矿充填体料浆的最优配比为:粒径0.15~0.30mm占16.7%,0.30~0.50mm占66.8%,料浆质量分数为70%,灰砂比为1∶4。     

水煤浆黏度的几种影响因素分析

研究了矿物质、粒度分布和搅拌强度对水煤浆黏度的影响.结果表明,实验使用的3种矿物质——高岭土、氧化铝和碳酸钙在降低水煤浆的黏度方面效果都比较明显,其中高岭土最显著,可以使黄陵水煤浆的黏度降低59.5%左右.适当的粒度级能有效改善浆体黏度,剪切率为116.5s-1时,枣庄煤级配制备的水煤浆的黏度值在820mPa·s~900mPa·s之间,而神准混煤级配制备的煤浆黏度值更低,处于500mPa·s~670mPa·s之间.同时搅拌强度的增加在一定范围内可以有效降低煤浆的黏度.     

炭素材料生产用煤沥青黏度的测定及其影响因素分析

炭素材料生产用煤沥青中作为黏结剂,测定黏结剂中黏度是根据美国SHRP计划推荐的布洛克菲尔德旋转黏度计（Brookfield,简称布氏黏度计）.对3种不同厂家沥青和一种标准沥青的表观黏度测定结果,分析了剪变率（转速）、测定时间和测定温度等因素对煤沥青表观黏度的影响,根据测定数据分析结果,并且提出了提高试验效率和测定方法的精度准确性.     

DNP/HMX熔铸炸药的流变性能

为了解3,4-二硝基吡唑(DNP)/HMX悬浮液在不同影响因素下的流变行为,采用Brookfield R/S Plus流变仪对其流变性能进行测试,分析了HMX含量、粒度、颗粒级配、体系温度以及不同添加剂对悬浮液流变性能的影响。结果表明,DNP单质为牛顿流体,表观黏度约为16.4mPa·s,比TNT高82%,比DNAN高140%;同一剪切速率下,DNP/HMX悬浮液表观黏度随固含量的增加而增加,当HMX质量分数为30%时,悬浮液近似牛顿流体;HMX质量分数高于30%时,表观黏度随剪切速率的增加呈指数型下降的趋势愈发明显;悬浮液表观黏度随颗粒粒径的增大和温度的增加而降低,当温度从95℃升到105℃时,黏流活化能(E)从29211J/mol增至38458J/mol;固含量为60%时,平均粒径(d50)分别为16.6μm和575.6μm的HMX颗粒的最佳质量比为1∶5,此时悬浮液表观黏度最小。N-甲基-4-硝基苯胺(MNA)降低了悬浮液的表观黏度,乙酸丁酸纤维素(CAB)和微晶蜡-80(MV80)增加了悬浮液的表观黏度。     

含微米级AP的HTPB推进剂工艺性能和力学性能

制备了含微米级AP(质量分数大于50%)的HTPB推进剂药浆和标准试件,利用流变仪测试了+20℃和-40℃时药浆的表现黏度,用材料试验机测试了标准试件的力学性能,讨论了增塑比、AP粒度级配、键合剂等对HTPB推进剂工艺性能和力学性能的影响。结果表明,当增塑比为0.42、AP粒度级配采用25%的120μm AP、30%的6~8μm AP和20%的1μm AP时,推进剂样品6h的表观黏度为1 267Pa·s,低温延伸率达到38%。     

级配粒度对宁东煤成浆性影响的研究

以宁东煤为研究对象,采用正交试验法进行了煤粉粒度分布对水煤浆成浆性能影响的分析研究。自制了不同颗粒区间的煤粉,并将各种粒径的煤粉配制成相同浓度的水煤浆,以水煤浆的黏度和流动性作为试验指标,探讨了不同粒度级配对宁东煤成浆性的影响。采用超声衰减粒度仪进行了粒度分布测定,并得到了分布曲线。试验结果表明:双峰级配的煤粉粒度级配合理,大颗粒和小颗粒之间相互填充,煤粉堆积效率达到最大,煤粉空隙中的水量最小,表现为浆体的黏度低、流动性好。     

Viscometry and rheology of coal water slurry

This paper presents the results of a detailed experimental study on rheological behaviour of coal water slurry (CWS). In contrast to earlier rheological studies at shear rates of rather narrow ranges, this study covered a much wider range of shear rates: 0–800 s⁻¹ in a rotational viscometer and 400–10000 s⁻¹ in a capillary viscometer. While the gap width of a rotational viscometer had no effect on the apparent viscosity of CWS, it was found that selection of proper tube dimensions in a capillary viscometer was important, Thus, the viscosities of CWS measured in both viscometers at the overlapping shear rates of 400–800 s⁻¹ were in good agreement. Consequently, it was possible to study the effect of shear rate higher than 800 s⁻¹ on slurry rheology. In addition, the effects of coal content, coal particle size and size distribution, and temperature on the slurry rheology were investigated. The slurry, a dispersion of coal particles in a pseudoplastic fluid, became more viscous and less pseudoplastic as the coal content was increased. The pseudoplasticity of a highly concentrated utility grind CWS approached that of a concentrated suspension of 40–50 μm solids in a Newtonian fluid. Also, the slurry pseudoplasticity was enhanced at a slightly elevated temperature, but significantly reduced as the shear rate exceeded a threshold dependent on coal content and particle size and size distribution.     

精细水煤浆的颗粒分形特征对燃烧特性的影响规律

利用神华、兖州和淮南3种煤制备了精细水煤浆,并对精细煤粉颗粒的粒度分布与表面分形特征、精细水煤浆的流变特性和不同升温速率下的燃烧特性进行了研究。结果表明随着精细煤粉的表面分形维数增大,其比表面积增大,粒度、孔径均相应减小,相同浓度下的精细浆的表观黏度值上升,精细水煤浆的着火温度和燃烧反应活化能降低。其中表观黏度值以淮南精细浆与兖州精细浆增加较多,在100 s^-1下都增加了740 mPa·s。着火温度和燃烧反应活化能都以淮南精细浆降低最多,其着火温度降低了41.36℃,燃烧反应活化能降低了77.71 kJ·kmol^-1。     

油煤浆黏温特性研究进展

煤直接液化技术是缓解石油供需矛盾、实现煤炭清洁高效利用的重要技术途径之一,油煤浆的黏温特性对其配制、输送、加压、预热及反应性能具有重要影响。本文从油煤浆黏温特性的变化规律、研究方法、变化机理、影响因素等方面的研究进展进行了综述。在升温过程中,油煤浆流变特性表现为非牛顿流体,具有剪切稀化特性;高温高压下黏度测定方法主要有4种;分析黏温特性变化机理：煤浆制备和升温阶段黏度变化主要由溶胀作用导致,高温阶段主要由煤裂解产生沥青质（尤其是前沥青烯）导致;从溶剂、煤的性质（煤阶、显微组分及粒径分布）、剪切速率、油煤浆浓度、催化剂和氢分压等方面分析了油煤浆黏温特性的影响因素。最后指出了未来油煤浆黏温特性的研究方向,为我国煤直接液化技术的进一步发展提供参考。     

纳米流体黏度和流变特性的试验研究

对纳米流体黏度和流变特性的研究有助于揭示纳米流体强化传热和传质过程的机理。选用无水乙醇为基液,应用两步法制备了稳定性良好的纳米流体,采用CPE40锥板式黏度计测量了不同纳米粒子、体积份额、粒子粒径和温度下的纳米流体的黏度,分析了黏度随这些因素的变化规律。结果表明,纳米流体黏度随纳米粒子体积份额的增加而增大,随纳米粒子粒径的增大而减小,随温度的增加而降低,且这些因素对不同纳米流体黏度的影响不同。此外,还用Brookfield DVⅢ＋LVDV-E流变仪测量了不同纳米流体的流变曲线,结果表明,在所配制的体积份额内,各纳米流体的黏度不随剪切速率的变化而变化,为典型的牛顿型流体。     

RHEOLOGICAL BEHAVIOR OF LOW-RANK COAL-WATER SLURRIES

The rheological behavior of low-rank coal-water slurries was studied using a Brookfleld Rheolog viscometer. A Sarpy Creek subbituminous coal from Montana, with particle sizes ranging from 0.044 mm to 0.223 mm, was used. The solids concentration in the slurry varied from 15 to 65 weight % and the temperature was maintained constant at 82°F. The rheological behavior of the slurry made from as received coal was compared with that of the slurry made from hot water dried coal

Coal-water slurries, made from both as received and hot water dried coal exhibited pseudoplastic behavior. The shear stress was found to be related to the shear rate by the power law model. As expected, the apparent viscosity was found to increase sharply with solids loading. It was also observed that the apparent viscosities of the slurries made from hot water dried coal were lower than those made from as received coal.     

RHEOLOGICAL BEHAVIOR OF LOW-RANK COAL-WATER SLURRIES

The rheological behavior of low-rank coal-water slurries was studied using a Brookfleld Rheolog viscometer. A Sarpy Creek subbituminous coal from Montana, with particle sizes ranging from 0.044 mm to 0.223 mm, was used. The solids concentration in the slurry varied from 15 to 65 weight % and the temperature was maintained constant at 82°F. The rheological behavior of the slurry made from as received coal was compared with that of the slurry made from hot water dried coal

Coal-water slurries, made from both as received and hot water dried coal exhibited pseudoplastic behavior. The shear stress was found to be related to the shear rate by the power law model. As expected, the apparent viscosity was found to increase sharply with solids loading. It was also observed that the apparent viscosities of the slurries made from hot water dried coal were lower than those made from as received coal.     

焦化废水制备水煤浆的成浆性能

焦化废水是一种典型的成分复杂、污染严重、处理难度大的工业废水。本文将焦化废水作为原料制备水煤浆,研究了温度、煤粉粒度对成浆性能的影响,通过扫描电镜照片与红外光谱探讨了对成浆的影响。结果表明,焦化废水的最大成浆浓度比去离子水稍低;在一定温度范围内,焦化废水水煤浆表观黏度随温度升高而降低,浓度越高黏度变化越明显;细煤粉的成浆性较差,粗煤粉占70%时,成浆性最好;扫描电镜和红外光谱的结果显示,焦化废水中的金属离子会吸附在煤粉表面,影响分散剂吸附,使浆体黏度上升。利用水煤浆技术处理焦化废水,可以通过简单的工艺和较低的成本,实现焦化废水无害化、资源化利用,具有良好的经济效益与环保效益。     

Rheological propertis of coal—oil mixture fuels

The rheological properties of coal—oil mixtures (COM) of a bituminous coal in four types of oil, grade 2, grade 4, light grade 6 and heavy grade 6, have been studied. Variables investigated were the coal concentration (0 – 60 wt.%), coal particle size (10 < d₅₀ < 40 μm), temperature (25 – 90 °C) and time effects (0 – 6 days).

Rheograms were obtained using the Ferranti-Shirley cone and plate viscometer. The COM was classified as a Newtonian fluid at coal concentrations up to 30 wt.% and as a Bingham plastic at higher values. The relative viscosity was found to increase rapidly with coal concentration, reaching 100 for a 60 wt.% of COM.

Both COM viscosity and yield stress decrease with increasing median particle size and decreasing slope of the particle size distribution. This effect is stronger at high solids concentrations.

The COM viscosity is much less sensitive to temperature than the base oil. The COM yield stress increases up to 350 Pa with increasing coal concentration, decreasing temperature and ageing.