The Evolution of Microstructure in Three-Component Granulation and Its Effect on Dissolution

The relationship between microstructure and dissolution rate of three-component granules was investigated. Granules were prepared by fluid bed granulation from sucrose spheres as model excipient, sodium chloride as model active ingredient, and polyethylene glycol (PEG) as in situ melt binder. A novel method for controlling the distribution of active ingredient within the granule was developed, based on suspending its particles in the binder prior to granulation. Granule microstructure was varied by systematically changing the NaCl particle size and the active/excipient ratio in granules. The dissolution rate of granules in water was measured by conductometry. A minimum was found in the functional dependence of dissolution time on NaCl fraction in the granule, in line with earlier computer simulations. The primary particle size was found to influence dissolution time in a nonlinear way depending on the fraction of available particle surface immersed in the binder. The intrinsic binder dissolution can therefore be rate-controlling if primary particles of the active ingredient are totally coated by binder. This was confirmed by comparing the dissolution times of granules prepared with PEGs of different molecular weight.     

Kinetics of fluidised bed melt granulation V: Simultaneous modelling of aggregation and breakage

The main purpose of this paper is to quantify the aggregation and breakage rates in fluidised bed melt granulation (FBMG) and to subsequently relate them to various experimental conditions. The earlier paper of this series (2004d, Powder Technology 143-144, 65-83) illustrated a sequence of development and verification work on a breakage model for FBMG, based on the population balance modelling work on tracer experimental studies. A new error-weighted integral technique was also developed, which allows simultaneous extraction of the aggregation and breakage selection rate constant, as well as the attrition constant that reveals the relative amount of attrition during FBMG. Further research is conducted here, as the similar modelling strategy is employed to extract the aggregation and breakage kinetics at different operating conditions. A series of plots revealing the influence of operating conditions (binder spray rates, bed temperature, droplet size and fluidising air flow rate) on these extracted constants are therefore established. The aggregation rate constant plots reveal that the particle aggregation rate is dependent on the amount of binder available per unit time, and hence scales directly with the binder spray rate. The aggregation rate is also observed to increase with increased bed temperature when a higher viscosity binder is used, but reveals a maximum aggregation rate for a less viscous binder. The aggregation rate also increases with larger droplet size and lower fluidising air velocity. The breakage selection rate and attrition constant plot both reveal no direct dependence on binder spray rate, due to the separation in time scale over which the granule breakage occurs. The breakage rate and the extent of granule attrition is also found to decrease with increased bed temperature and increased fluidising air velocity. Due to scatter in the data, it is not possible to deduce any sensible trend on the influence of droplet size on its relative breakage rate and attrition.     

ASBR系统及其启动分析

本介绍ASBR系统的主要工艺特点，并依据ASBR中能形成颗粒化的特点，就一些国外研究中增大颗粒化以加快启动的实验性结论加以分析。     

一种混合药剂自动造粒设备

为解决国内某硅系混合药剂依赖于人工生产,劳动强度大、生产效率低、生产环境恶劣、生产安全保障 性差等问题,设计一套自动对混合药剂进行造粒的设备。介绍该设备的主要技术要求、机械系统设计及组成,采用 PLC 与伺服系统控制进行作业时间、速度等参数的设定,分别对电气控制硬件和软件进行设计,并通过实际生产验 证。应用结果表明：该设备能实现某硅系混合药剂的自动造粒生产,生产效率高。     

固体物料造粒碰撞过程有限元仿真研究

为研究工艺参数对物料抛圆整形的影响,基于Abaqus仿真软件和内聚元法,对物料碰撞壁面过程进行数值模拟,研究颗粒在不同速度及结合能碰撞后的效果。结果表明:随速度增大,颗粒碰撞过程中剥落区增大,且在较高速度下(≥3 m/s),颗粒形貌变化较大。相同碰撞速度下,随颗粒结合能增大,颗粒剥落区减小。在碰撞速度为3 m/s,结合能为0.04J时,碰撞后颗粒的形貌更好,物料造粒效果较好。     

降低熔体造粒复合肥料缩二脲含量的实践

在塔式熔体造粒复合肥料生产过程中,影响缩二脲生成的因素主要包括混合物料加热温度、停留时间及其物料水分和含氮量.针对影响因素,给出了降低缩二脲含量的措施.改造后,效果显著,产品中的缩二脲质量分数可控制在0.9%～1.3%.     

Ni-65WC粉末的雾化造粒与激光熔覆层组织和冲蚀性能研究

为提高煤炭开采、洗选和煤化工的煤机装备耐冲蚀性能,利用雾化造粒和激光熔覆技术制备高WC含量Ni/WC复合熔覆层,通过组织观察、力学性能检测、腐蚀及磨损实验对比研究了雾化造粒和激光熔覆过程中Ni/WC复合熔覆层的组织、结构演变,并基于射流式冲蚀分析了材料的冲蚀行为。结果表明:喷雾干燥Ni/WC团聚复合粉末的球形度与粘结剂含量成正比,而粒径则与雾化器转速成反比。激光熔覆后,Ni/WC熔覆层由Ni、WC和W₂C相组成。其中,在熔覆过程中WC出现了熔解与析出变化,形成了层状共晶→棒状、针状→块状结构的富W和富Ni相。在冲蚀磨损工况下,WC有效改善了Ni/WC熔覆层冲刷磨损性能,磨损率为0.097 g/(m²·h),相比Q235A钢降低约23%。此时,细小的WC均匀镶嵌在磨损表面的粘结相中起到强化作用。同时,Ni/WC熔覆层的剥落处表现出明显的塑性特征,为典型的韧性破坏。     

Compact,lightweight, high‐frequency oscillation device using electromagnetic force and corresponding bead formation phenomena. Development of high‐frequency oscillating arc (1st report)

The current work expresses considerations about some of the differences of the fused flux CIS-F10 obtained by means of fragmentation in water and with an air jet. The comparisons are established taking into account their respective granulometric distributions, shapes and grain densities, as well as the energy and the time spent in the process of obtaining each of these variants. Criteria for the physical process of flux fragmentation with an air jet and its influence over the aspects formerly mentioned are also included. The principal findings were that the process for obtaining the fused flux CIS-F10 granulated with an air jet consumes 37% less energy and 25% less time than the one performed with pouring water. The solidness grade of the spherical grains, granulated with air, (with pycnometric density 2.31 g/cm³), with a granulometric distribution more continuous than that of the granules in water, contributes to the increase of the apparent density (11%) of the flux and promotes the creation of artificial granulometric distributions, counteracting the rolling effect during welding.     

高塔造粒生产复合肥技术

介绍目前比较典型的塔式造粒生产复合肥的技术,指出造粒塔塔高选择的基本原则及高塔造粒生产复合肥工艺控制中的一些基本方法:原料选择与配方原则,熔融混合温度及混合时间的控制原则,造粒喷头的选择等。     

高塔造粒复合肥冷却新工艺

提出以地下水为冷媒预冷却空气并对空气减湿的高塔造粒复合肥冷却新工艺。介绍其工艺流程、工艺设备以及实施效果，可使物料良好冷却，保持颗粒外观圆整度，降低生产成本。