PET连续固相缩聚工艺及主要影响因素

介绍了大连合成纤维研究设计院自主研发的10 kt/a连续式固相缩聚技术的生产工艺。从切片形状、结晶度及结晶形态、缩聚前预热、缩聚时间、氮气的纯度及流量等方面,讨论了固相缩聚主要影响因素。     

补充风对水平管高压密相气力输送影响的模拟研究

针对水平管高压密相气力输送数理模型的缺陷与不足,引入Savage径向分布函数修正的颗粒动理学理论、基于Berzi摩擦压应力模型构建的摩擦应力模型以及修正的三段式曳力模型,在欧拉-欧拉方法的基础上建立了一个能同时兼顾水平管高压密相气力输送中稀相流、过渡流以及密相流输送特性的三维非稳态数理模型。并采用该数理模型考察了补充风对水平管高压密相气力输送的影响,模拟结果精准地预测了水平管压降及其随补充风的变化规律,而且其预测的水平管固相体积浓度分布与ECT图也是相吻合的,从而验证了数理模型的可靠性。模拟结果表明：随着补充风的增加,气固两相速度和湍动能以及颗粒拟温度增大,固相体积浓度减小。     

PET主要品质指标影响因素探讨

从生产实际角度,探讨了PET产品主要品质指标的影响因素,如色值、端羧基值、二甘醇值及特性黏度等受温度、压力、原料配比、添加剂品质等的影响情况。     

正压开放式气力输送水泥粉体临界料位影响因素实验研究*

本文采用相似理论模拟建立了目前工业常用的正压开放式气力输送系统。该系统可以有效监控固体质量流率、固体料位、气力输送及气体流量等参数。在此系统上,以水泥粉体为输送物料,压缩空气为输送动力进行开放式气力输送研究。通过改变输送母管内的输送压力、气体流量、固体质量流率等操作参数得出临界料位的变化规律,进而得出影响临界料位的主要因素,为本类开放式气力输送的临界料位的确定与监控提供指导。     

Numerical simulation on dense phase pneumatic conveying of pulverized coal in horizontal pipe at high pressure

A kinetic–frictional model, which treats the kinetic and frictional stresses in an additive manner, was incorporated into the two fluid model based on the kinetic theory of granular flow to simulate three dimensional flow behaviors of dense phase pneumatic conveying of pulverized coal in horizontal pipe. The kinetic stress was modeled by the kinetic theory of granular flow, while the friction stress is from the combination of the normal frictional stress model proposed by Johnson and Jackson [1987. Frictional–collisional constitutive relations for granular materials, with application to plane shearing. Journal of Fluid Mechanics 176, 67–93] and the modeled frictional shear viscosity model proposed by Syamlal et al. [1993. MFIX documentation and theory guide, DOE/METC94/1004, NTIS/DE94000087. Electronically available from http://www.mfix.org], which was modified to fit experimental data. For the solid concentration and gas phase Reynolds number was high, the gas phase and particle phase were all treated as turbulent flow. The experiment was carried out to validate the prediction results by three kinds of measurement methods. The predicted pressure gradients were in good agreement with experimental data. The predicted solid concentration distribution at cross section agreed well with electrical capacitance tomography (ECT) image, and the effects of superficial velocity on solid concentration distribution were discussed. The formation and motion process of slug flow was demonstrated, which is similar to the visualization photographs by high speed video camera.     

浅析粗对苯二甲酸产品透光率及其影响因素

简要阐述了CTA产品的透光率与PTA产品b值的相互关系,通过控制CTA的透光率,可保证PTA的b值,达到提高PTA产品品质的目的。结合生产实际,分析了PX纯度、氧分压、反应停留时间、反应器回流、母液循环率、二次氧化、无机杂质等对透光率的影响规律。     

Visual analysis of particle bouncing and its effect on pressure drop in dilute phase pneumatic conveying

During the pneumatic conveying of plastic pellets, it has been observed that materials with similar physical characteristics may develop substantial difference in pressure drop, whose cause is not fully understood. This experimental study focused on the dynamic behavior of the particles during conveying and its influence on pressure drop.The bouncing of the particles during pneumatic conveying in dilute phase was visually analyzed by means of a high speed video camera. The experiments included two different plastic pellets of similar size and density but different modulus of elasticity. The conveying trials were carried out in a 0.052 m I.D. aluminum pipe conveying system approximately 35 m long. The loading was controlled by an airflow control valve and a variable speed drive rotary valve. For each material, a series of tests were performed creating a matrix of six solids rates for five different air velocities. During the conveying trials a high speed video camera was used to record the actual particle motion in a horizontal section with fully accelerated flow. The videos showed significant difference in bouncing between the soft and the hard pellets. The soft pellets showed very random and intense bouncing with strong rotation, which affected the rebound considerably. In fact, some particles bounced even backwards. On the other side, the hard pellets showed significantly less bouncing and rotation.In addition to the high speed videos, in each test the pressure drop was measured in the horizontal and vertical directions. As expected, a significant difference in pressure drop was recorded for the same conveying settings when using the different materials. The pressure drop showed a close relation to the bouncing of the particles, being much higher for the soft pellets.It can be concluded that the increased pressure drop, developed by the soft polyethylene pellets, is in part due to the multiple times the particles must be reaccelerated during their transit through the conveying system. Additionally, the reduction in the average particle velocity increases the drag force. All of this resulted in up to 3-fold increase in pressure drop across the conveying line compared to the hard polyethylene pellets that showed significantly less bouncing.     

水平管加压密相煤粉气力输送数值模拟

针对加压密相气力输送,对现有的颗粒静摩擦力模型进行适当修正,并将其与颗粒动理学理论相结合,建立了可以描述加压密相气力输送的气固湍流流动状况的多相流模型。该模型充分考虑了颗粒间碰撞和摩擦力作用,以及气相和颗粒团湍流脉动之间的相互作用。采用该模型对水平管内加压密相气力输送进行了三维数值模拟研究,模拟得到了气相和固相的速度、浓度和湍流强度分布,以及压降梯度的变化规律,再现了颗粒沉积层的形成和运动的动态过程。并进行了加压密相煤粉气力输送试验研究,预测的压降梯度与试验测量结果相符合。     

胶接用胶粘剂固化过程中温度预测及影响因素研究

针对单搭接接头,根据胶粘剂固化过程中的传热情况,将其温度场简化为无内热源的热传导问题,将平均换热系数看作固化温度的函数,采用集总参数法,得到胶粘剂固化过程中温度的预测公式,并用实验对公式计算结果进行了验证。运用该公式,分别讨论了固化温度、固化时间、被粘物材料属性、被粘物厚度、搭接长度、被粘物长度、胶粘剂初始温度、搭接宽度对胶粘剂固化过程中的温度影响规律。结果表明,前面5个因素对胶粘剂固化过程中的温度影响较大,后面两个因素基本无影响,当搭接长度相同,且与被粘物长度比值小于0.3时,被粘物长度也基本无影响。     

聚二甲基硅氧烷的改性技术及其渗透汽化性能的影响因素

介绍了聚二甲基硅氧烷(PDMS)的改性技术,总结了不同改性方法在渗透汽化中的应用,分析了影响PDMs膜渗透汽化性能的影响因素,指出了PDMs膜存在的问题及其发展方向.     

回转窑热工状况影响参数的数值模拟

以某炭素厂φ2.3 m×55 m的回转窑作为研究对象,运用流体模拟软件Fluent 和Matlab 分别对回转窑内气体空间和物料料层内的传热过程进行了模拟,预测了回转窑参数如二、三次供风量和位置、翻料装置、物料填充率、窑转速等对窑内温度场的影响。结果表明合理布置二、三次风供风量和位置、设定翻料装置的尺寸和个数能够有效提高窑内温度,进而提高煅后焦质量;合理增加物料填充率和提高窑转速既能够提高回转窑产能,又能够保证煅后焦质量。     

提升管反应器介尺度结构影响规律的数值模拟研究

提升管反应器存在典型的颗粒聚团介尺度结构,其分布特性对气固流动、反应有重要影响,对介尺度结构影响规律进行分析有助于为反应器的设计与优化操作提供基础信息。采用基于能量最小多尺度（EMMS）方法的曳力模型建立了提升管气固两相流动模型,考虑了颗粒聚团对气固相间动量传递的影响。此外,进一步通过考虑颗粒聚团的存在以及颗粒聚团的非均匀性对化学反应的影响,提出了描述介尺度结构对反应速率影响的修正因子,与气固流动模型进行耦合,建立了基于介尺度结构的流动-反应综合数学模型,并进行了模型验证。进一步应用该模型,对工业催化裂化提升管反应器的流动-反应特性进行了模拟分析。结果表明,该模型可以合理描述提升管气固相互作用,能够预测出壁面附近存在较多介尺度结构的分布特性,由于聚团的存在使得重油组分难以与催化剂充分接触,生成汽柴油的反应速率较低,转化较慢,聚团的分布特性导致靠近边壁处的重油组分浓度较高,汽柴油组分浓度较低;汽柴油在聚团内部的流动阻力较大,在聚团内发生过量的二次反应生成较多焦炭,导致壁面处焦炭浓度较高。与传统基于平均化而未考虑聚团影响的模型相比,基于介尺度结构的模型所预测的汽油收率最佳值与工业实际相接近。因此,基于介尺度结构的流动-反应综合数学模型可以合理描述提升管内进行的流动-反应耦合特性,并能揭示介尺度结构对催化裂化反应过程的影响,有望为工业提升管装置反应终止剂技术的开发提供重要的基础信息。     

盐水精制过程及影响因素

综述了盐水精制过程,浅析影响因素,结合澄清桶内盐水净化过程,探讨提高出力和净化效果的一些措施。     

低压法焦炉气制甲醇的影响因素探讨

介绍了10万t/a低压焦炉煤气制甲醇装置的工艺流程,采用C307铜基甲醇合成催化剂。结合实际生产数据,分析了影响甲醇产率的主要因素,包括原料气(焦炉气)气量、压力、温度、空速、氢碳比、催化剂的毒物以及设备性能。生产操作和经验表明,提高甲醇产率需要多因素综合考虑,在气量一定的条件下,温度与压力波动越小,甲醇产量越高;根据动力消耗和催化剂生产强度,空速一般控制在4 000~20 000 h-1;在入塔气中φ(CO2)一般控制在2%~5%,对甲醇合成有利;硫化物、氯化物以及羰基铁等金属毒物必须有效脱除,以提高甲醇合成产率,并延长催化剂使用寿命;通过提高设备性能,可以保持生产的稳定性,提高甲醇产量。     

复合肥料的吸湿性及其影响因素

通过对复合肥吸湿性能的测定,得出各种配方复合肥的临界相对湿度,并对复合肥临界相对湿度与物料温度、原料成分之间的关系进行了研究,指出硝基复合肥的临界相对湿度受m(硝铵)/m(磷铵)的影响明显。     

UV厌氧胶的制备及其影响因素研究

以聚氨酯丙烯酸酯(PUA)为基体、甲基丙烯酸-β-羟乙酯(HEMA)为活性稀释剂、异丙苯过氧化氢(CHP)为引发剂、N,N′-二甲基苯胺为促进剂、糖精为助促进剂、二苯甲酮(BP)/叔胺为光引发剂和对苯二酚为稳定剂,采用双引发体系和双固化[UV(紫外光)、厌氧固化]体系制备PUA基UV厌氧胶。通过单因素试验法优选出制备UV厌氧胶的最佳工艺条件。结果表明:当w(HEMA)=20%、w(CHP)=2%、w(光引发剂)=3.0%、w(N,N′-二甲基苯胺)=w(糖精)=0.8%和w(对苯二酚)=0.06%时,UV厌氧胶的综合性能良好,其光固化定位时间为8 s、剪切强度超过5 MPa。     

The influence of particle shape on flow modes in pneumatic conveying

The transportation of particles along pipes or ducts using an imposed gas flow is known as pneumatic conveying. The type of granular flow in such systems is strongly dependent on the imposed gas flow rate, and can be categorised by a distinct set of modes. These modes range from dilute flow, where the grains are entirely suspended in the gas, to moving dunes and slug flow, in which the bore of the pipe is blocked by a slow moving plug of material. Understanding the transitions between these modes is critical to the design and application of pneumatic conveying systems. Particle shape is a crucial factor in systems with gas–grain interactions but has so far been overlooked in models of pneumatic conveying. We carry out a series of simulations using the discrete element method coupled to gas flow and show that particle shape is critical to the transition between different flow modes. Particles which are spherical, or nearly spherical, transition to slug flow at high gas flow rates, whereas non-spherical particles transition instead to dilute flow. We show the lower voidage fraction in beds of non-spherical particles is crucial to explaining this behaviour.     

导叶式旋流器内油滴的聚结破碎及影响因素

利用流场测试实验和模拟计算对导叶式旋流器的内部流场和湍流性能进行研究,得到导致旋流场中油滴发生聚结破碎现象的内因为时均速度梯度引起的黏性剪切力和湍流流动引起的高剪切应力及湍动能,并分析了油滴破碎的主要发生部位。同时为宏观考察导叶式旋流器内油滴聚结与破碎相对作用强弱,验证了旋流器的分离性能作为表征量的可行性,并在此基础上,利用导叶式旋流器的分离性能实验结果对油滴聚结破碎发生的外因进行研究,结果表明导向叶片的结构参数（叶片数和叶片出口角）和旋流器的操作参数（入口流速、溢流率、分散相入口浓度和操作温度）均会影响到油滴在旋流器中的存在和运动形态。