腐殖酸基水煤浆分散剂的制备及性能研究

采用水溶液自由基共聚法制备了腐殖酸-烯丙基磺酸钠接枝共聚物(HAS),并通过FT-IR和XRD对其进行了结构表征.将HAS和传统的萘磺酸甲醛缩合物(SNF)分散剂应用于神木煤的制浆,考察了浆体的表观黏度和静态稳定性.研究表明,HAS的应用性能优于SNF,在HAS用量为0.6wt%时,水煤浆(成浆浓度为63wt%)黏度为392mPa·s,168h的析水率为4.47;测定了HAS和SNF在煤表面的物理化学性质,结果表明,HAS在煤表面呈现明显多层吸附特征,吸附量比SNF大,XPS分析也说明了这一点.HAS能更有效地降低水在煤表面的接触角,这表明HAS对煤具有良好的润湿作用.此外,HAS在煤表面的zeta电位绝对值也比SNF略小.     

Artificial neural network approach for rheological characteristics of coal-water slurry using microwave pre-treatment

Detailed experimental investigations were carried out for microwave pre-treatment of high ash Indian coal at high power level(900 W) in microwave oven. The microwave exposure times were fixed at60 s and 120 s. A rheology characteristic for microwave pre-treatment of coal-water slurry(CWS) was performed in an online Bohlin viscometer. The non-Newtonian character of the slurry follows the rheological model of Ostwald de Waele. The values of n and k vary from 0.31 to 0.64 and 0.19 to 0.81 Pa·sn,respectively. This paper presents an artificial neural network(ANN) model to predict the effects of operational parameters on apparent viscosity of CWS. A 4-2-1 topology with Levenberg-Marquardt training algorithm(trainlm) was selected as the controlled ANN. Mean squared error(MSE) of 0.002 and coefficient of multiple determinations(R~2) of 0.99 were obtained for the outperforming model. The promising values of correlation coefficient further confirm the robustness and satisfactory performance of the proposed ANN model.     

Effect of the benzene ring of the dispersant on the rheological characteristics of coal-water slurry: Experiments and theoretical calculations

In this study,low-rank coal-water slurry(LCWS) was prepared using polyoxyethylene dodecylphenol ether(PDPE) and polyoxyethylene lauryl ether(PLE),respectively.A combination of experiments and simulations was used to investigate the pulping properties and microscopic mechanism of the LCWS samples prepared using the two agents,so as to explore the influence of benzene ring on the performance of dispersant.The results of the LCWS preparation experiments revealed that the pulp-forming performance of PDPE exceeded that of PLE.When LCWS concentration is 62%,64%,and 66%,the apparent viscosity corresponding to PDPE is 247.80,504.17,and 653.10 mPa·s,and the apparent viscosity corresponding to PLE is 548.10,1470.61,and 1549.98 mPa·s,respectively.The C_(1000)(When the apparent viscosity is 1000 mPa·s,the corresponding concentration of LCWS is defined as C_(1000)) values of PDPE and PLE are 67.60% and 62.95%,respectively.In addition to the van der Waals forces and hydrogen bonds between the PDPE and/or PLE molecules and coal,the benzene rings of PDPE present π-π stacking effect with the aromatic rings of coal.That could facilitate and strengthen the adsorption of PDPE on coal,which would be conducive to further improving the dispersion of coal particles.The two dispersants have no significant difference in effect on the pyrolysis of LCWS.The simulation results indicated that the times for PDPE and PLE molecules to reach flat adsorption state on coal are approximately 290 and 565 ps,respectively.The self-diffusion coefficient(D) of the PDPE and PLE on coal is 3.16 x 10~(-6) and6.57×10~(-6) m~2/s,respectively,and their interaction energies with coal are 785.71 and 648.60 kcal/mol,respectively.The results of the simulation calculations demonstrated that PDPE adsorbed on coal easier than PLE,and its binding is more stable than that of PLE owing to the π-π stacking effect,which is conducive to uniform dispersion of coal in solution.The simulation results confirmed the experimental results.     

印染退浆废水制备水煤浆的实验研究

利用印染退浆废水制备了水煤浆,研究了印染生产中两种退浆剂NaOH和H2O2与淀粉、聚乙烯醇(PVA)、聚丙烯酰胺(PAM)3种不同浆料产生的退浆废水对水煤浆成浆性能的影响.结果表明,NaOH作为退浆剂时,3种浆料废水制备的水煤浆黏度随着NaOH浓度的增加,呈现先升后降再升的趋势,且NaOH浓度为3.9～5.0g/L时3种退浆废水水煤浆黏度最大,而NaOH浓度为7.0～11.0g/L时水煤浆黏度最小;在NaOH和H2O2联合作用退浆时,随着H2O2的加入,3种水煤浆的黏度先速降后趋平缓,在H2O2浓度为2.5～6.5g/L时,3种水煤浆黏度出现相似较低值.     

不同分子量磺化丙酮-甲醛缩聚物在煤上的吸附及水煤浆流变性能

以丙酮、甲醛及亚硫酸钠为原料,采用磺化缩聚法,通过控制缩合时间和温度合成了一系列具有不同分子量的磺化丙酮-甲醛(SAF)水煤浆分散剂,并对其分子结构进行了表征,证明了它是一个含有磺酸基和羟基亲水基团的脂肪族柔性链高分子.同时研究了它们对彬长煤的吸附和水煤浆流变性能的影响,并与萘系进行了对比.结果表明,相对分子量适中(Mw=38 541)的SAF-2对水煤浆的分散降黏性最好,其分散性和稳定性均优于萘系分散剂;通过吸附等温线的测定,得出SAF在彬长煤上呈Langmuir单分子层吸附,且SAF分子量越小,其吸附能力K越大,吸附量也越大;用Herschel-Bulkley模型对浆体流变曲线进行拟合,发现不同分子量的SAF水煤浆体都呈现"剪切变稀"的流变特性,为假塑性流体,且分子量适中的SAF-2流动指数最大,吸附量与水煤浆流动性密切相关.     

两性离子型腐殖酸接枝共聚物水煤浆分散剂的合成及性能

以腐殖酸(HA)、烯丙基磺酸钠(SAS)、二甲基二烯丙基氯化铵(DMDAAC)等为原料,以过硫酸钾为引发剂,采用水溶液自由基聚合原理,制备出了一种新型两性离子型腐殖酸接枝共聚物水煤浆分散剂——HA-SAS-DMDAAC(HSC).通过红外光谱、热重分析和差示扫描量热分析等对聚合物的结构及热力学性能进行了表征和分析,并考察了阳离子单体用量、引发剂用量、反应温度等对水煤浆性能的影响.优化的工艺条件为:m(DMDAAC)∶m(SAS)∶m(HA)=0.3∶1.0∶2.0,引发剂用量7.0wt%,反应温度80℃.结果表明,两性离子型腐殖酸接枝共聚物分散剂(HSC)比阴离子型腐殖酸接枝共聚物分散剂(HS)具有更好的降黏效果,并明显增强了浆体的静态稳定性.     

乳化沥青稀浆封层技术在G207改建工程中的应用研究

介绍乳化沥青稀浆的配制原理及主要技术性质，对乳化沥青稀浆用于道路封层从施工工艺，技术等方面进行了探索。     

Suspension mechanism and application of sand-suspended slurry for coalmine fire prevention

North and west China has abundant coal resources, however, such resources make these regions prone to serious mine fire disasters. Although the copious sand and fly ash resources found in these areas can be used as fire-fighting materials, conventional grouting is expensive because of water shortage and loess particles. A new compound material (i.e., a sand-suspended colloid), which comprises a mineral inorganic gel and an organic polymer, is developed in the current study to improve the quality of sand injection and reduce water wastage when grouting. The new material can steadily suspend the sand, through the addition of a small amount of colloid yielding steady sand-suspended slurry. The process of producing the slurry is convenient and quick, overcoming the shortage of sand-suspending thickeners which need heat and are difficult to produce. The space work model based on the theory of the double-electric layer is established to study the suspended mechanism of the solid particles in the sand-suspended colloid. The dispersion effect of the sand-suspended colloid is demonstrated by the incorporation of the electrostatic effect by the double-electric layer and the steric hindrance effect on the sand particles, ensuring the stability of the colloid system and the steady suspension of sand particles in the sand-suspended colloid. Mechanical analysis indicates that the sand is suspended steadily under the condition that the rock sand particles stress on the lower part of the fluid is less than the yield stress of the colloid. Finally, the fire-prevention technology of sand suspension was applied and tested in the Daliuta Coal Mine, achieving successful results.     

煤泥高效调浆理论研究与应用

基于煤粒与捕收剂充分接触和有效黏附是实现煤泥调浆前提条件的认识,应用Sommer-feld颗粒间碰撞模型,导出了调浆过程中颗粒分散后的碰撞概率,并用颗粒绕流效应对碰撞概率进行了修正,考察了高剪切条件下实际流场中油滴与煤泥颗粒碰撞的规律.提出了捕收剂与煤泥颗粒有效吸附概率的概念,讨论了煤泥高效调浆的技术途径,并进行了调浆试验.结果表明:提高调浆剪切强度,保证调浆时间是确保浮选精煤回收率和质量的关键,过度调浆不利于提高浮选精煤回收率.     

基于改进滤失试验的泥水盾构动态泥膜渗透特性研究

为了研究泥膜对泥水盾构开挖面稳定性的影响,通过改进滤失试验研究泥水盾构动态泥膜的渗透特性,提出泥水舱泥浆密度的计算方法,获得时间与泥浆滤失量的关系曲线和泥膜的本构参数（孔隙比-渗透系数-压力的相互关系）,推导动态泥膜平均厚度的计算公式. 由试验压力增长引起的泥膜孔隙比的减小,可以降低泥膜的渗透系数. CMC-Na对泥浆的改性效果最好. 添加高分子材料的泥浆形成的泥膜厚度变小,泥膜厚度与泥膜平均渗透系数存在正比关系. 在盾构掘进过程中,泥膜厚度会发生周期性变化,动态泥膜的周期时间取决于刀具的布局和刀盘的转速. 动态泥膜的平均厚度约为最大泥膜厚度的2/3.     

基于水泥净浆流变性的振动-剪切等效理论

为了分析振动条件下水泥净浆的流变特性,解释水泥净浆流变性模型的转化机制,提出适用于振动条件下水泥净浆流变性分析的振动-剪切等效理论. 根据修正HI理论和回转黏度仪径向分层算法,计算振动条件下回转黏度仪内水泥净浆流场的剪切速率,将振动台正弦振动过程转化为对水泥净浆的剪切过程. 采用自制回转黏度仪,开展20 Hz振动频率下的HI参数标定试验和30 Hz振动频率下的水泥净浆黏度试验. 结果表明,HI参数标定结果与数值计算结果之间的误差约为7%,水泥净浆的试验黏度与数值计算的黏度之间的误差为8%并趋于收敛状态. 增大振动频率,水泥净浆的黏度逐渐减小并达到峰值,流变性模型逐渐由Bingham模型转变为Hershel-Bulkley模型,最后转变为Power-Law模型.     

冲击映像法及其在超长距离顶管施工泥浆套检测中的应用

泥浆减阻是超长距离顶管施工中的一项关键技术,泥浆套厚度与工程质量息息相关。基于冲击映像法的基本原理,提出一种精确掌握顶管施工注浆充盈状况的快速检测方法,并通过模型试验和现场试验对检测方法的有效性进行研究。根据模型试验结果,将归一化冲击响应强度作为反映泥浆充盈状况的评价指标,成功应用于苏州一大型引水工程中。研究表明：较传统压力观测法,冲击映像法在检测泥浆套厚度方面有明显的优越性,有效提高了检测效率和高阻力区的识别能力,据此对泥浆薄弱区进行定点补浆,节约了施工成本,可在同类工程中推广使用。     

铅酸蓄电池拉浆黏合剂的选择与研究

提出采用拉浆工艺制备铅酸蓄电池薄型极板.对铅膏中加入黏合剂种类的选择与要求进行了详细论述.阐述了拉浆工艺对铅膏的要求.研究了铅膏中加入黏合剂对电池性能的影响.对拉浆铅膏的反应机理进行了探讨.实验证明,B型聚醚类黏合剂适用于铅酸蓄电池的拉浆工艺,采用拉浆法制造薄型极板的铅酸蓄电池可以提高活性物质利用率,改善大电流放电性能.     

磷酰三肼的合成、表征及应用

以三氯氧磷与水合肼为反应物,合成了新型磷氮系阻燃剂磷酰三肼,探讨了其合成工艺,采用元素分析、红外光谱分析对该化合物的结构进行了表征,用DSC、TG—DTG对其热性能进行了研究,并将其与聚丙烯腈共混刮膜,测定了共混膜的极限氧指数值．结果表明,所合成化合物的结构与预期的相一致,具有优异的热性能;当其在共混膜中的质量分数为30％时,共混膜的极限氧指数值可达25．7．     

奶牛粪沼液对小麦-玉米轮作土壤团聚体有机碳组分的影响

为探明奶牛粪沼液连续施用对耕层土壤团聚体及有机碳活性的影响,本研究以小麦-玉米轮作体系为研究对象,进行了2年奶牛粪沼液连续施用的田间小区试验,分析了沼液施用后表层(0～10 cm)和亚表层(10～20 cm)土壤水稳性团聚体及其总有机碳与各活性组分含量的变化特征.研究发现：施用沼液后土壤团聚体稳定性显著(P<0.05)增加,土壤小团聚体有向大团聚体演化的趋势,且沼液施用量越大,耕层土壤中大团聚体增加越多;施用沼液后耕层土壤碳库存分别比施用化肥的处理增加25.9%～35.2%,高活性有机碳的变化对土壤碳库的影响最大;施用沼液会通过活性碳的输入提升耕层土壤碳库活度,且亚表层土壤碳库活度对外源有机物的输入更加敏感,大团聚体中活性较高有机碳增加是主要驱动因子.     

浆态床低压甲醇合成反应器的数模分析与设计(I)——催化剂颗粒床层轴向分布

本文对热模条件下的浆态床低压甲醇合成反应器进行了数模分析 ,通过模拟计算 ,重点讨论了温度、表观气速、颗粒直径、床层高度、催化剂浓度等主要参数与反应器内催化剂颗粒轴向分布的相互关系以及颗粒轴向分布对甲醇合成过程的影响 .模拟结果表明 ,颗粒直径、床层高度、催化剂浓度对催化剂的轴向分布影响较为显著 ;改善催化剂的轴向分布可明显提高甲醇合成速率     

Settling,consolidation and shear strength behaviour of coal tailings slurry

The volume change and shear strength behaviour of tailings slurry with the changes in gravimetric moisture content is important to effectively utilise the storage volume and analysis of dam failure potential. Consolidation testing of tailings from a slurry-like to soil-like state is a critical task, and conventional consolidation apparatus does not have the capability of doing such testing, as the tailings slurries contain high water content. Settling tests conducted on slurries having a 25% solids concentration showed very low efficiency; final sediment was still slurry-like. An intrinsic point was identified based on pore water pressure dissipation during consolidation tests in a slurry consolidometer that can define two states of the tailings i.e. slurry-like and soil-like. In the slurry-like state, the volume change was greater for Slurry 2 than Slurry 1, while the inverse was observed in the soil-like state. The evolution of peak vane shear strength with the changes in moisture content was almost similar for both samples and obeyed the power function. Regression models have been developed and validated to predict the shear strength of materials at any gravimetric moisture content or void ratio.     

砂层盾构隧道泥水劈裂试验与数值研究

开展砂层盾构隧道泥水劈裂平面模型试验,研究不同覆土厚度条件下的泥水劈裂破坏机制、土体表面竖向位移和土体内部土压力变化规律. 结果显示,劈裂机制为加压泥浆向掘削空间表面砂层渗透形成致密砂层及其表面泥膜（泥膜-砂层结构）,泥膜-砂层结构在泥浆挤压作用下发生拉剪破坏. 劈裂压力随覆土厚度的增加呈近似线性增大. 劈裂扩展从刀盘顶部起始分别呈“斜直线”或“先竖直后斜线”型向上扩展. 基于自主开发的模拟泥水劈裂的有限元计算程序,参照模型试验建立二维数值模型,计算获得与模型试验较一致的劈裂扩展形态以及土体内部竖向位移与水平位移的变化规律. 结果表明,土体竖直向位移主要分布在刀盘上方以劈裂面为边界的“三角形”区域内,土体水平位移主要分布在掘削面土层.     

Synthesis and characterization of polyamides based on dimer acid

A series of dimer acid-based polyamides were synthesized by melt-polycondensation of dimer acid and various aromatic diamines, and were characterized by Fourier transform infrared spectrum (FT-IR) and nuclear magnetic resonance (¹H NMR). The physical properties of the polyamides, such as glass transition temperature, melting temperature, decomposition temperature and mechanical properties were also investigated. The polyamides’ intrinsic viscosity ranges from 1.8 dL·g⁻¹ to 2.2 dL·g⁻¹, and the melting temperature ranges from 140 °C to 181 °C. The glass transition temperatures, observed from dynamic mechanical analysis, fall in the range of 34.8–48.2 °C. The physical and mechanical properties of the resultant polyamides are similar to those of the PA1212. The heat resistance and mechanical properties of poly (4, 4′-diphenylsulfone dimeramide) (PSD) and poly(4, 4′-diphenyl dimeramide) (PPDI) are comparable to those of PA1212.