【作者】 刘鸿雁；

【导师】 王一平；

【作者基本信息】 天津大学 ， 化工过程机械， 2007， 博士

【摘要】 软胶囊作为一种剂型,在药品、食品、化妆品等领域有着广泛的应用发展前景。在软胶囊的干燥过程中,尚有粘连、破裂、能耗大、能源利用不合理等问题,研究对流干燥过程中软胶囊的热质传递性能对降低能耗、提高产品质量、指导生产具有重要的理论意义和实用价值。本文从实验和理论两个角度进行了研究。在本研究中,采用有代表性的脉通软胶囊和维E软胶囊为研究对象,以红外热像仪和精密电子天平为主要测试仪器,研究了加热空气温度、风速及相对湿度对软胶囊传热和传质过程的影响。实验结果表明,提高热空气的温度,虽然提高了传热速率,但在第二降速阶段干燥速率下降,当热空气温度超过30℃时,最终湿含量反而偏高;随着热空气风速的提高,传热速率增加,干燥速率在第一降速阶段呈现加快趋势,软胶囊的最终湿含量稍有降低;而热空气相对湿度的变化,对传热过程影响很小,但随着热空气相对湿度的降低,干燥速率提高,最终湿含量明显降低。根据实验结果,本文提出在强化外界干燥条件时,应采用降低空气相对湿度,适当增大热空气速度的方法,而热空气温度不要过于提高,反之,将达不到理想的干燥效果。理论研究以扩散理论为基础,建立了对流干燥过程中明胶软胶囊热质传递的耦合模型,随后对该模型采用有限单元法离散并进行了数值模拟。经验证,数值模拟结果与实验数据吻合较好,可以用于预测囊皮为明胶且药液中不含水分的软胶囊在干燥过程中温度和湿含量的分布。数值模拟结果表明软胶囊在干燥过程中温度和湿含量的分布及变化规律是:传热过程中,软胶囊从外向里温度逐渐降低,主要的传热阻力存在于囊皮中;囊皮的湿含量分布呈现不均匀的状态,同一时刻囊皮表层的湿含量最低,囊皮内层的湿含量最高,在干燥的整个过程中,湿含量的分布一直处于这种不均匀的状态,干燥结束后,囊皮表层与内层之间还保持着较大的湿含量差。本文研究表明,湿明胶软胶囊是一种难于干燥的物料,在对流干燥的热质传递过程中,质量扩散起控制作用,干燥一定时间后,没有必要继续为软胶囊提供大量的热量,而应该对胶囊进行缓苏,等到内部的湿分向外扩散后,再提供热量,去除湿分,对于年产10亿粒软胶囊的生产规模,预计每年可节约能量约100吨标准煤。更多还原

【Abstract】 Soft capsule as a drug form prospects well in the field of medicine, food and cosmetics. But there exist many problems such as conglutination, cracking, large energy consumption and unreasonably using energy in its drying process. It is very important to research the properties of heat and mass transfer in soft capsules during convective drying process for cutting down energy consumption and improving the quality of products. The research carried out at the angle of experiment and theory.In order to research the drying characteristics of soft gelatin-capsules, the experiment was engaged in the convective drying apparatus and MaiTong soft gelatin-capsules and Vitamin E soft gelatin-capsules were used as the object. The surface temperature of soft gelatin-capsules was measured by an infrared thermal imager and the weight was tested by electronic balance with high accuracy. The results show that with the increase of the air temperature the rate of heat transfer increase, but the drying rate in the second falling rate period decrease and which causes the final moisture content of soft capsules higher when the air temperature is over 30℃;With the increase of the air velocity the heat transfer rate and drying rate in the first falling rate period all increase , the final moisture content of soft capsules slightly drop;The change of the hot air relative humidity influences on heat transfer very small, but the drying rate raises as decreasing the air relative humidity and which leads to the final moisture content of soft capsules obviously drop. According to the experimental results the method of decreasing the air relative humidity, suitable increasing the air velocity and not over increasing the air temperature is presented.On the base of diffusion theory the coupled model of heat and mass transfer was established. The equation was simulated by the method of finite element. The simulated results were validated to agree well with the experimental data and can be used to forecast the distribution of temperature and moisture content in the soft gelatin-capsules whose liquid drug don’t contain water. The simulated results indicate that the temperature of the soft capsules decrease gradually from the exterior to interior and the main resistance of heat transfer centralize on the shell of the soft capsules;The distribution of moisture is not uniformly. The moisture content is the highest on the outer surface of shell of soft capsules and is the lowest in the inner surface. After drying the big moisture difference exists between the outer surface and inner surface.The paper presents that the wet soft gelatin-capsules are difficult to dry. Heat and mass transfer process is mainly controlled by mass transfer. After a period of drying it is not necessary to continuously provide a great deal of heat but to temper the capsules. After the moisture diffuses from the inner of soft capsules to the outer the hot air need to be provided again. It is estimated that about 100 ton standard coal can be saved for the production scale of 100 million soft capsules per annum.更多还原