Design process of a vacuum freeze dryer: Simultaneous endpoint determination using measurement of both temperature and relative humidity

Experiments were conducted with pure water to study the various temperature and humidity parameters that can be used to develop the process of a vacuum freeze dryer (VFD). Both temperature and humidity sensors were applied to investigate characteristics such as the resistance offered during drying, heat-transfer coefficients, moisture content, diffusivity, and others that can influence the process of vacuum freeze-drying during primary drying. These experiments helped to develop an efficient and optimized process. We discuss the importance of various parameters on drying and the ways in which one can accomplish the experiment of drying. Two conditions, humidity and temperature, were combined to obtain a concurrent output for the start and endpoint of steps involved in freeze-drying. From the process discussed, we state that when % RH lies between 8% and 10%, primary drying begins and when it lies between 1% and 3%, secondary drying begins. Practical Applications The practice applications for developed techniques in this manuscript would be food industry, storage of smallpox vaccines, manufacturing of enzymes, proteins, or drugs, and other bio-related applications by a vacuum freeze dryer (VFD).

Automated summary

Experiments were conducted to study the impact of temperature and humidity on the process of vacuum freeze-drying. The findings led to the development of an efficient and optimized drying process. The start of primary and secondary drying was found to be influenced by relative humidity.