细颗粒添加组分流态化研究进展

介绍了细颗粒聚团流态化的类型;从添加组分的种类、添加量以及粒径大小3个方面,综述了近些年来国内外研究者对细颗粒添加组分流态化的研究进展,进一步阐述了细颗粒中添加磁性大颗粒后在外加磁场作用下的流化性能的研究情况,重点指出了细颗粒添加组分流态化研究中存在的问题和发展方向,提出应开展细颗粒聚团与其添加颗粒之间的相互作用机理的研究,以得出定量的关系,从而为工业应用提供理论依据。     

反胶团或微乳液法制备超细颗粒的研究进展

本文对超细颗粒的各种化学制备方法进行了综合评述，并重点介绍了一种新的超细颗粒制备法──反胶团或微乳法。从以下几个方面对反胶团或微乳法制备超细颗粒的研究工作进行了归纳和总结：各种用于制备超细颗粒的反胶团或微乳体系，已经制得的超细颗粒种类，反胶团或微乳中颗粒的形成机理，以及反胶团或微乳法制备超细颗粒的影响因素等。     

超细颗粒流化聚团尺寸的预测模型

根据聚团形成机理和分析方法的不同对超细颗粒流化聚团尺寸预测模型进行分类和评述,将模型值与实验结果进行比较。结果表明,不同模型仅能预测相应实验条件下的聚团尺寸,适用性较差。指出为获得适用范围广泛的聚团尺寸预测模型,应深入研究聚团形成机理以及各种作用力的计算和参数选取,建立更符合实际情况的机理模型。     

操作参数对液固流化床分级性能的影响

为提高传统液固流化床的分级性能,利用斜板沉降技术研制一种带倾斜板的液固流化床分级装置;以二氧化硅粉体为研究对象,采用单因素实验法考察了流化速度、物料质量浓度和进料流速3个操作参数对液固流化床分级性能的影响。结果表明:随着流化速度的增大,溢流级各粒径部分分级效率增大,综合分级效率先增大后减小;随着物料的质量浓度的增大,溢流级细颗粒部分分级效率先增大后减小,综合分级效率先增大后减小;随着进料流速的增大,溢流级细颗粒部分分级效率先增大后趋于稳定,综合分级效率先增大后减小;当斜板倾角为60°、流化速度为0.07 m/s、物料质量浓度为8 g/L、进料流速为0.023 m/s时,综合分级效率可达63.16%。     

超细颗粒的相对论性时空新理论

提出了超细颗粒的相对论性时空变换理论和相对论性质量与速度的关系。利用功能原理得到超细颗粒的相对论性动能表示,由此得到光子的静止质量和动量的明确表示。     

鼓泡流化床稀相空间颗粒粒度分布的时变特性

鼓泡流化床稀相空间的催化剂颗粒粒度分布一方面与流化床流化速度有关，另一方面与流化床中藏量的细小颗粒跑损有关，即随着流化床操作的连续进行，流化床系统中的细颗粒不可避免的存在跑损，进而影响到稀相空间的颗粒粒度分布。由于这种跑损是连续发生的，因此稀相的颗粒粒度分布变化具有时变特性。选用催化裂化平衡催化剂和二维流化床，在连续流化操作过程中采集稀相空间中的颗粒样品，分析颗粒的粒度分布，考察稀相空间中颗粒粒度分布随流化操作时间的变化。结果表明：随着流化床系统中细颗粒的跑损，稀相颗粒粒度分布的中位粒径和峭度逐渐增加，稀相空间的颗粒逐渐粗化，经过一段流化操作时间后颗粒粒度分布变化趋于稳定。     

微乳液的结构及其在制备超细颗粒中的应用

本文对微乳液的结构及特征作了概括的论述，着重对Ｗ／Ｏ微乳液制备超细颗粒的研究进行了评述，包括超细催化剂粒子、半导体粒子、磁性材料、陶瓷材料、感光材料等，分析了微乳液滴中超细颗粒的形成机理，讨论了用该法制备超细颗粒的影响因素，提出了这一研究领域的研究方向。     

超细颗粒的量子尺寸效应新理论

根据么正变换理论,并结合ＳＵ（１ ,１）Ｌｉｅ 代数,对超细颗粒的量子尺寸效应进行详细研讨。结果表明,超细颗粒的能级随时间变化,并且是精确的。     

超细颗粒和超细颗粒材料

超细颗粒和超细颗粒材料韩仲琦（天津水泥工业设计研究院，天津３００４００）１什么是超细颗粒众所周知，我们把眼睛可以看见的物质体系叫作宏观体系（ｍａｃｒｏｓｃｏＰｉｃＳｙｓｔｅｍ），把理论研究中所接触到的原子、分子大小体系叫作微观体系（ｍｉｃｒｏｓｃｏｐ...     

超细颗粒的阻尼振动量子尺寸效应新理论

根据实么正变换理论 ,并结合SU( 1 ,1 )Lie代数 ,对超细颗粒的阻尼振动量子尺寸效应进行详细研讨。结果表明 ,超细颗粒阻尼振动系统的能级和波函数随时间变化的规律较复杂。通过系统坐标期望值和动量期望值的计算 ,证明系统的微观态是可以精确测准的。     

二元气-固流化系统临界流化速度的研究

在直径为4cm的有机玻璃流化床中,对由不同尺寸和质量分数的铁矿石和煤颗粒组成的二元气-固流态化系统进行了流化特征的实验研究,得到了该系统的流化特性曲线,给出了临界流化速度和二元系统混合颗粒平均直径之间的关系,用该关系式对临界流化速度进行了预测,并且将预测值和实验值进行了比较。结果表明,当煤颗粒的质量分数为10%时,临界流化速度umf与颗粒直径的平方dm2的关系为umf=0.13dm2+1.2;当煤颗粒的质量分数为20%时,两者的关系变为umf=0.12dm2+1.2,预测值与实验值误差在10%以内。     

Computational simulations using a low density ratio-based kinetic theory of granular flow in subcritical water fluidized beds

Hydrodynamics of fluid and particles were simulated using a low density ratio-based kinetic theory of granular flow (KTGF) in subcritical water (SbW) fluidized beds (FB). Results indicated that the fluidization state of the SbW-particles mixture changes progressively from particulate to aggregative, indicating that a transitional state exists between aggregative and particulate fluidization. Wavy-like and churn-like flows were found along bed height in SbW FBs, unlike the homogeneous fluidization found in atmospheric water (AW) FBs and wispy-annular-like flow found in supercritical water (SCW) FBs. The predicted axial velocities and RMS fluctuating velocities of particles agreed approximately with measurements reported in the literature. The effect of fluid pressure and temperature, inlet fluid velocity and particle density on distributions of solid volume fractions and velocities were analyzed in SbW FBs.     

Experimental study of fluidization characteristics of Geldart-D particles in pressurized bubbling fluidized bed

The pressurized bubbling fluidized bed shows great advantage in retreating municipal solid waste because it could effectively capture CO₂ and enhance the reaction rate of the process of combustion and gasification. In the present work, fluidization characteristics of Geldart-D particles at elevated pressure were experimentally investigated, such as flow pattern, pressure drop, minimum fluidization gas velocity. At the same fluidization gas velocity, as elevating operating pressure, the fluidization of Geldart-D particles became more intense, the bubbles got larger, the standard deviation and the power density of dominant frequency of the pressure drop signal increased. While, under the same fluidization number, as increasing operating pressure, the fluidization of Geldart-D particles became smoother, the bubble size decreased, both the standard deviation and the power density of dominant frequency of the pressure drop signal decreased. It seems that, under elevated pressure, the fluidization behavior of Geldart-D particles would transition to that of Geldart-B particles. Finally, the minimum fluidization velocity of the Geldart-D particles was found decreased with the increase of the operating pressure. A new correlation for the prediction of the minimum fluidization velocity of Geldart-D particles at elevated pressure was also formulated based on the present experimental results.     

Fluidization of molten salt fluid-particles using low density ratio kinetic theory of granular flow

To deduce and analyze the hydrodynamics of molten salt fluid and particles, computational simulations were performed using a low density ratio kinetic theory of granular flow with two-fluid model in a fluidized bed. Two types of transition fluidization of molten salt fluid-particle mixtures were found in the fluidized bed. One represented the coexistence of wave-like flow at the bottom regime and large scale turbulent regime with chunk-like flow at the bed upper. The other characterized the coexistence of particulate fluidization near the bottom regime and particle aggregations at the upper part along bed height. The molten salt fluid-particle mixtures transited from particulate fluidization to transition state with increasing molten salt fluid temperatures, inlet fluid velocities and particle diameters and densities. The computed expansion heights and fluid volume fractions agreed with measured data in a water-particles fluidized bed.     

Study on the flow behavior of irregular plastic particles in a spout-fluid bed with a draft tube

This work presents an experimental investigation on the hydrodynamic performance of a draft tube spout-fluid bed with irregular particles. Nonmetal particles from waste printed circuit boards (NPCBs) were used as a spouting solid, and polypropylene (PP) particles were selected as an assistant to fluidization particles. The flow pattern, minimum spouting velocity (U_ms), and minimum spout-fluidization velocity (U_msf) were investigated under different operating conditions. The irregular cohesive particles from NPCBs showed poor flowability and channeling, which restrained stable spouting in the spout-fluid bed. The quality of fluidization and spouting improved when greater than 40?wt.% PP particles were added into the NPCB/PP mixtures. The mechanism was that the PP particles accelerated the movement of NPCB particles. Meanwhile, lower density differences between NPCB and PP particles decreased the segregation of the mixtures. The minimum spouting velocity decreased with an increase in fluidization gas velocity and the ratio of NPCB particle in the NPCB/PP mixtures. Two flow patterns, unstable spouting and unstable spouting fluidization, were observed over a large range of gas velocity. The ranges of gas velocity in these two flow patterns enlarged with the increase in mass fraction of NPCB particles within the NPCB/PP mixtures.     

Studying the effect of direction and strength of magnetic field on fluidization of nanoparticles by recurrence analysis

Effect of the intensity and direction of the magnetic field was studied on fluidization of titanium oxide nanoparticles (anatase phase) mixed with ferromagnetic Iron (III) oxide nanoparticles using the recurrence analysis. The bed expansion and visual observation revealed that these particles operate in the ABF regime in all cases. Minimum fluidization velocities were obtained through the standard deviation of pressure fluctuations. Agglomerates samples were taken to study the effect of the magnetic field on the size of agglomerates. It was observed that at low field strength, the vibration has a major effect on fluidization than the magnetic force. At field strengths less than 400 Gauss, the vibration of solenoid improved the quality of fluidization by decreasing the size of agglomerate and minimum fluidization velocity, regardless of the field direction. At field strengths greater than 400 Gauss, the upward direction increases the interaction of agglomerate which results in a stochastic pattern of fluidization and lower ABF characteristics. At high magnetic field strengths, the effect of field direction becomes more noticeable. At high field strengths, the downward field results in less movement of the bed material and resistance against fluidization as well as the formation of larger bubbles and their deterministic effect on the bed.     

The hydrodynamics of liquid-solid and gas-liquid-solid inverse fluidized beds with bioparticles

The hydrodynamic characteristics, such as minimum fluidization velocity (U_lmf for liquid-solid (LS) system and U_g,if for gas-liquid-solid (GLS) system) and bed expansion ratio (BER), of liquid-solid and gas-liquid-solid inverse fluidized beds (LSIFB and GLSIFB) with bare particles and particles with biofilm were investigated. In the LSIFB system, U_lmf and BER of the bare particles were independent of the solids loading. For bioparticles, the increase of the biofilm thickness reduced U_lmf and increased BER, suggesting that the fluidizability increases with the presence of the biofilm. In the GLSIFB system, the initial fluidization gas velocity (U_g,if) and the complete fluidization gas velocity (U_g,cf) both increased with increasing particle diameter and decreasing particle density under fixed superficial liquid velocities. Biofilm attachment led to a decrease of both U_g,if and U_g,cf, and an increase of bed expansion, again suggesting increased fluidizability with the presence of biofilm.     

超细粉体分级填料塔的结构设计

从气固流态化原理出发介绍了分级填料塔的工作原理,借助波纹填料塔的一些计算方法,进行了超细粉体分级填料塔的结构设计。固体颗粒由于颗粒大小的不同,其重量亦不同,使其上升的曳力亦不同,故在固定风速下,不同粒径的颗粒在分级填料塔内由上至下实现分层,团聚的颗粒受到填料的不断冲击而达到分散,提高了整体的分级效果。将该设备用于固体颗粒的分级,取得了显著的分级效果,展现了广阔的应用前景。