Optimization Of A Pharmaceutical Freeze-Drying Equipment And Experimental Study

Due to the advantages of lyophilization, many pharmaceutical plants adopt lyophilization to dry various kinds of medicine. But lyophilization is the most expensive of all drying operations both in capital investment and in operating expense. In order to improve the quality and economical efficiency of the pharmaceutics, the optimization of freeze-drier and process of freeze-drying are always in the focus of freeze-drying research. In present thesis, the optimization of freeze-drier and process of freeze-drying are discussed:(1) A set of pharmaceutical freeze-drying equipment has been developed and the optimization was carried out on the basis of freeze-drying system, which can work very well below -80℃(2) During the process of freeze drying, the running time of the refrigeration system is the longest, so the energy consumption is the most.; Cooling rate has much impact on the quality of freeze-dried medicine. Thus, we have emphasized on the optimization of this refrigeration system. The optimization of the COP and the cooling rate is presented in this thesis.(3) The theory of heat and mass transfer in low temperature and low pressure is also discussed and the way to isolate harmful heat transfer in drying chamber is found through experiments.(4) In the process of freeze drying, there are four factors which have much impact on the quality of freeze-dried medicine and energy consumption of freeze drying process: freezing rate, heating rate, vacuum, annealing. The first three factors have been discussed in detail in other literatures. In this thesis, the experiment of sucrose and mannitol is performed in order to explore the impact of annealing on the drying process, based on the theoretical study.