喷雾流化床中含液滴作用的气固流动和造粒过程研究

发布时间：2018-05-10 22:12

本文选题：喷雾流化床 + 造粒　；参考：《东南大学》2017年硕士论文

【摘要】：喷雾流化床造粒在制药、化工、食品等领域得到了广泛应用。流化造粒是气固两相流动、液体蒸发及结晶、颗粒涂布等的综合过程,颗粒生长速率受到流化、干燥、物质特性等多种因素的影响。在喷雾流化造粒过程中,组织良好的流化是必要条件,颗粒生长速率是描述造粒过程的核心参数。本文在喷雾流化床包衣实验台上,考察流化失效和颗粒生长速率的相关规律。搭建了喷雾流化床造粒实验系统,主要包括:流化床本体、喷雾系统、配气系统、测量系统等。采用内置中心筒和布风板中心区域强化布风的结构,组织颗粒在床内的有序循环;双流体雾化喷嘴布置在中心筒内,由底向上喷雾,强化液滴与颗粒的接触;通过预热流化气体控制物料干燥过程。通过喷水-停止喷水/加热实验,可以观察到流化床从正常流化到流化失效,到再次恢复流化的过程。结果表明:增加喷液速率,流化失稳速率增加;增加床料量和颗粒粒径,流化失稳速率减小。压力波动方差可以有效反映床内流化质量,方差随着流化失稳而变大,随流化恢复而变小。提高进风温度、喷雾压力,减小液体粘度,可以抑制流化失效的发生。床内液固比是决定流化质量的重要因素,控制床内液固比有助于维持包衣过程的平稳进行。在喷雾流化造粒实验中,采用染色料液定性揭示了颗粒包衣过程,随包衣过程的进行,料液附着颗粒程度逐渐增加,颗粒颜色不断加深。本文实验中,颗粒生长方式属于层式生长方式,颗粒增重随时间近似线性增加。进一步,详细比较了颗粒直径、流化风速、料液喷入速率、粘结剂浓度对颗粒增重率及生长速率的影响。发现提高料液喷入速率,颗粒生长速率明显提高。流化风速过小或过大均不利于颗粒包衣。床料粒径较小时,颗粒更易形成团聚。增加粘结剂浓度,颗粒生长速率增加。
[Abstract]:Spray fluidized bed granulation has been widely used in pharmaceutical, chemical, food and other fields. Fluidized granulation is a comprehensive process of gas-solid two-phase flow, liquid evaporation and crystallization, and particle coating. The particle growth rate is affected by fluidization, drying and material properties. In the process of spray fluidization is a necessary condition and particle growth rate is the core parameter to describe the granulation process. In this paper, the correlation between fluidization failure and particle growth rate was investigated on a spray fluidized bed coating test bench. A spray fluidized bed granulation experiment system was built, including fluidized bed body, spray system, gas distribution system, measurement system and so on. The inner central cylinder and the central area of the air distribution plate are used to strengthen the air distribution structure, and the ordered circulation of the particles in the bed is organized, and the two-fluid atomizing nozzle is arranged in the center cylinder and sprayed from the bottom up to strengthen the contact between the droplets and the particles. The drying process is controlled by preheating fluidized gas. The fluidized bed can be observed from normal fluidization to fluidization failure and to restarting fluidization through water-spraying-stopping water spray / heating experiment. The results show that the rate of fluidization instability increases with the increase of injection rate, and decreases with the increase of bed material and particle size. The variance of pressure fluctuation can effectively reflect the fluidization quality in bed. The variance increases with the fluidization instability and decreases with the fluidization recovery. Increasing inlet air temperature, spray pressure and reducing liquid viscosity can inhibit fluidization failure. The liquid-solid ratio in the bed is an important factor to determine the fluidization quality, and controlling the liquid-solid ratio in the bed is helpful to maintain the smooth process of coating. In the spray fluidized granulation experiment, the particle coating process was revealed qualitatively by dyeing liquid. With the coating process, the adhesion degree and color of particles increased gradually. In this paper, the particle growth mode belongs to the laminar growth mode, and the particle weight increases linearly with time. Furthermore, the effects of particle diameter, fluidization velocity, feed injection rate and binder concentration on particle weight gain and growth rate were compared in detail. It was found that the particle growth rate increased obviously when the injection rate was increased. Too small or too large fluidized wind speed is not conducive to particle coating. When the particle size of bed material is small, it is easier to form agglomeration. The particle growth rate increased with the increase of binder concentration.
【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ021

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