球形氨合成催化剂的开发和应用

本文论述了球形氨合成催化剂的开发过程及熔体直接成球工艺制造的高强度球形催化剂的几个主要特点和发展潜力 对已开发成功的几种球形催化剂的物化性能和氨厂的应用情况和经验等作了报道。     

基于图像扫描的散料颗粒离散元建模及应用

在带式机输送物料的离散元数值模拟中,非规则外形物料颗粒建模一般采用球形近似体但会降低模拟精度.试验研究了对实际土石方颗粒图形进行扫描处理,先建立其简化的三维模型,再导入离散元仿真软件中进行填充,建立土石方颗粒模型的方法.通过离散元软件EDEM对颗粒模型进行试验标定,再通过实际工程现场进行验证,结果表明图像扫描法建模所测...     

对立窑熟料性质的研究

水泥立窑是一种立式不动的煅烧设备,窑内物料自窑顶靠重力整体下移,逐步完成物料组分间的物理化学过程。由于物料颗粒不能沿径向或上下单个活动,每当断面上通风不均时,物料颗粒受热也不均匀,使立窑熟料质量差别甚大。为了探讨外观不同熟料产生的原因及其对水泥质量的影响,我们对几个立窑厂生产的熟料进行了物化性质的研究。一、试验结果及讨论我们在A、B、C三个机械化立窑厂和     

水下切粒PCW系统流场调控及优化

针对高聚物颗粒在水下,切粒工艺PCW系统的水力输送环节中出现的碰撞及滞留现象,避免其造成颗粒堵塞、成品颗粒粘连、料粉含量高的问题,以改善颗粒在水力输送环节竖直输送管段中的碰撞及滞留现象为目的,对高聚物颗粒的最佳水力输送速度进行研究。采用CFD-DEM耦合数值模拟与竖直提升试验台实验相结合的研究方法,分析了输送水流速对高聚物颗粒在竖直管段中碰撞及滞留现象的影响。结果表明,当低相输送时(颗粒体积分数低于1%),高聚物颗粒的碰撞及滞留现象均随输送流速增大而有明显改善,且存在最佳优化值。对于直径为5～15 mm、密度为1. 2～2 g/cm3的高聚物颗粒,其竖直输送段流速最佳优化值为1. 9 m/s。     

条形长链烷烃脱氢催化剂载体制备研究

通过对条形长链烷烃脱氢催化剂载体制备方法研究,制备出物化性质及催化活性与球形参比剂相似的条形催化剂,催化活性可以满足评价指标要求。采用条形载体与球形载体比,能提高产品收率,降低载体生产成本,又能降低球形载体制备过程中带来的环境污染问题。     

弹簧输送加料

弹簧输送加料是利用它与电机直接联接的弹簧高速旋转,依靠物料间及物料与弹簧间的磨擦力,使粉状物料或小颗粒物料沿着弹簧螺旋方向前进的方向在管内输送,输送方向可为水平、倾斜、弯曲或垂直提升。这种输送器结构简单,易自制,密封性能好,适于输送颗粒状物料。     

影响催化裂化催化剂成型的因素分析

通过磨损、粒径以及SEM等分析手段对催化剂微球成型的影响因素进行了考察,以便实际生产过程中更好地控制催化剂微球的球形度、磨损以及粒径.当喷雾塔的入口温度较低时,干燥速率慢,微球球形度差,粘连明显;入口温度过高,又造成干燥速率过快,裂纹现象比较明显.胶体固相质量分数、粒径对催化剂成型影响也较大,固相质量分数低时,微球球形度差,粘连比较明显;固相质量分数过高时,物料输送困难,催化剂微球会出现明显的裂纹现象;降低胶体粒径,成型微球球形度变好,粒径分布均匀;增加黏结剂的质量分数能够明显改善催化剂微球的耐磨损性能.     

合成氨球形催化剂颗粒大小对活性影响的研究

通过对不同粒度球形催化剂的活性试验．探讨其颗粒大小对活性的影响，证明使用小颗粒球形催化剂可提高催化剂的有效利用率，增加合成氨产量。     

喷动流化床最大喷动压降的多因素影响与关联

基于截面200 mm×20 mm,高1600 mm,锥角60°的矩形喷动流化床,以二组分混合颗粒、单一组分球形颗粒及非球形颗粒为物料进行最大喷动压降的实验研究.结果表明,最大喷动压降随静止床高、颗粒密度、颗粒球形度及二组分混合颗粒体系中沉积组分分率增加而增大,随流化气速增大而减小;增大颗粒粒径或喷口宽度,呈现先减小后增...     

合成氨球形催化剂颗粒大小对活性影响的研究

通过对不同粒度球形催化剂的活性试验，探讨其颗粒大小对活性的影响，证明使用小颗粒球形催化剂可提高催化剂的有效利用率，增加合成氨产量。     

用MATLAB神经网络预测气力输送过程物料破碎率

物料在气力输送过程中的破碎率大小,是评判气力输送系统及输送工艺优劣的重要参数之一.利用MATLAB语言,将炭黑气力输送系统各位置的压力数据输入BP神经网络,用训练好的网络模型进行仿真,对炭黑的破碎率进行了预测.与实验结果对比,采用BP神经网络对炭黑破碎率的预测具有比较高的精确度,可对气力输送系统的优化设计以及输送工艺参数的优化选取提供指导.     

炭黑气力输送中破碎率及气量控制的试验研究

近年来，随着气力输送行业的发展，人们对输送后物料的破碎率要求趋于苛刻。在炭黑密相气力输送试验的基础上，对炭黑输送中的破碎率进行了正交试验，并研究了输送气量控制、气速对破碎率的影响，认为气速是影响粒子破碎率的主要因素，在保证输送正常（不堵管）的情况下，降低输送气速，可大大地降低炭黑在气力输送中的破碎率。     

用氯丁-多异氰酸酯改性胶粘剂粘接传送带接头

根据橡胶传送带接头的断裂形貌 ,对断裂原因进行了分析 ,介绍了氯丁 -多异氰酸酯改性胶粘剂的性能及修复传送带接头的具体工艺     

A study of the effect of different iron oxide pigment grades on properties of an industrial latex coating

Two red iron oxide pigments with similar properties but prepared by different chemical processes were obtained for evaluation. One process provided a pigment described as rhombohedral in shape; the other was described as spheroidal. The pigments were incorporated into an industrial latex coating formulation at the same pigment volume concentration. Properties of the liquid formulations, wet applied films, dried films, and free films were measured. Representative tests run were viscosity, gloss, adhesion, and prohesion. Differences in the degree of coalescence, accelerated corrosion testing, surface appearance, and mechanical properties were observed. Based on experimental data, conclusions were made attempting to correlate pigment morphology with coating properties. However, other inherent differences, such as particle size distribution, were found to obscure the singular effect of particle morphology.     

双转子连续混炼机混合过程物理模型的建立

建立了双转子连续混炼混合过程的物理模型，分析了影响其混炼段融体输送过程和混合过程的主要因素，并提出：转子混炼段融体输送量与转子螺棱几何形状，物料粘度，混炼段融体压降等有关；转子对物料的混合过程与转子组合（螺棱交汇区长度）转子螺棱几何形状，转子转速等因素有关。     

影响FCC再生立管输送催化剂影响因素的分析

再生立管是FCC装置再生器和提升管反应器之间再生催化剂循环的输送管,其操作复杂性在于立管内催化剂的流态受多种因素影响。本文中在1.0Mt/a FCC装置上,通过测量立管改造前后不同操作条件时的轴向压力分布,考察再生立管输送催化剂的影响因素。生产运行结果表明,影响立管操作的主要因素包括催化剂密度和平均粒径、立管几何结构、滑阀安装位置、松动风性质和流量等;选用低密度催化剂和高黏度流化介质可以减小气泡尺寸,维持反应温度稳定;松动风流量应根据立管推动力、滑阀压降和反应温度及时调整,避免填充流。另外,立管结构和滑阀的安装位置对立管推动力影响较大,分析结果可供立管设计和装置改造参考。     

密相气力输送系统的比较

在建材、冶金、化工等行业中,现广泛应用的稀相气力输送技术,其气流速度高、固气比低,耗气量大,且不适用粒径大和相对体积质量大的物料输送。而低速、低压的密相栓流输送新技术,既可在输送过程中实施对物料的加热、冷却和烘干;且当物料速度减少或粉料流量增大时,具有较高的系统稳定性。目前,国内外已相继开发了多种密相栓流气力输送系统,其成栓方式包括有脉冲气刀式、挤压式和重管式等多种,均各具特点。其中,脉冲气刀栓流输送系统在运行时,输送固气比高、耗气量低,且成栓方式简单、有效,应成为密相气力输送设计时优先考虑的系统。     

Experimental investigation and stability analysis on dense-phase pneumatic conveying of coal and biomass at high pressure

Conveying characteristics and flow stability are very important for design and control of a conveying system at high pressure. The influences of operating parameters and material properties on conveying characteristics were investigated in an experimental test facility with a conveying pressure up to 4MPa. Wavelet transform and Shannon entropy analysis were applied to analyzing pressure drops through horizontal pipe in order to obtain the stability criterion. Results indicated that the mass flow rate of biomass decreased, while the mass flow rate of pulverized coal increased at first and then decreased with the increase in fluidization velocity. Solid loading ratios for four kinds of powders decreased with the increase in fluidization velocity. Conveying phase diagrams and pressure drops through different test sections of pulverized coal and biomass at high pressure were obtained and analyzed. The influences of coal category, fracture characteristics and particle size on conveying characteristics were determined.     

粉粒状物料性能与其气力输送特性(待续)

迄今气力输送仍然主要依靠在全尺度试验台上进行气力输送试验，以此来判定给定的散料是否可以密相输送和何种流动模式。然而，正是粉粒状物料的性能对它的气力输送特性有决定性影响，因此．研究散料处理最有前途的课题之一，就是要能事先通过对料性试验数据分析来预测该散料的气力输送特性，从而为选择(设计)装置(系统)作好准备。气力输送特性由粒子特性和散料特性两部分组成，全面阐述了较新的对这两类特性的细节，以及它们对散料的相属和流动模式的影响和分类。     

Copolymerization of ethylene/α‐olefins using bis(2‐phenylindenyl)zirconium dichloride metallocene catalyst: structural study of comonomer distribution

Catalysts have a major role in the polymerization of olefins and exert their influence in three ways: (1) polymerization behaviour, including polymerization activity and kinetics; (2) polymer particle morphology, including bulk density, particle size, particle size distribution and particle shape; and (3) polymer microstructure, including molecular weight regulation, chemical composition distribution and short‐ and long‐chain branching. By tailoring the catalyst structure, such as the creation of a bridge or introducing a substituent on the ligand, metallocene catalysts can play a major role in the achievement of desirable properties. Kinetic profiles of the metallocene catalyst used in this study showed decay‐type behaviour for copolymerization of ethylene/α‐olefins. It was observed that increasing the comonomer ratio in the feedstock affected physical properties such as reducing the melting temperature, crystallinity, density and molecular weight of the copolymers. It was also observed that the heterogeneity of the chemical composition distribution and the physical properties were enhanced as the comonomer molecular weight was increased. In particular, 2‐phenyl substitution on the indenyl ring reduced somewhat the melting point of the copolymers. In addition, the copolymer produced using bis(2‐phenylindenyl)zirconium dichloride (bis(2‐PhInd)ZrCl₂) catalyst exhibited a narrower distribution of lamellae (0.3–0.9 nm) than the polymer produced using bisindenylzirconium dichloride catalyst (0.5–3.6 nm). The results obtained indicate that the bis(2‐PhInd)ZrCl₂ catalyst showed a good comonomer incorporation ability. The heterogeneity of the chemical composition distribution and the physical properties were influenced by the type of comonomer and type of substituent in the catalyst. Copyright © 2010 Society of Chemical Industry