When freeze dryer operating costs account for a relatively large proportion of total output value, reducing operating costs and improving production efficiency are particularly important.
Factors affecting freeze dryer operating costs primarily come from three aspects:
1. Material influences, such as eutectic point, thermal sensitivity, geometric size, and thickness, all significantly impact the required drying time and operating costs.
2. The influence of the process route employed, such as determining and managing the material’s final freezing temperature, freezing rate, heating temperature, heating rate, and timing, all affect drying speed and operating costs.
3. The influence of the freeze dryer itself. The freeze dryer’s performance, extreme parameter indicators, overall capacity, energy efficiency, operational stability, and ease of operation all have a significant impact on drying efficiency and operating costs, sometimes significantly.
Several Ways to Reduce Operating Costs
1. Materials with relatively simple compositions generally have higher eutectic points. For example, vegetables have a freezing temperature of only around -15°C, resulting in shorter freezing times and, consequently, shorter heating times, lower energy consumption, and lower operating costs. Materials with complex compositions, such as those containing organic or inorganic components such as salt, sugar, fat, amino acids, and solvents, have lower eutectic points. The lower the freezing temperature, the longer the freezing time and, consequently, the longer the heating time, leading to higher operating costs.
2. Some biological products, such as fungi and vaccines, are highly heat-sensitive and cannot be heated at excessively high temperatures (-15°C to 30°C). Heat absorption is difficult, requiring long drying times and resulting in high operating costs. Materials with less heat sensitivity, such as ordinary foods, can be heated at higher temperatures (75°C to 100°C), significantly shortening drying times and reducing operating costs.
3. For the same weight, smaller, thinner, and looser materials have a larger surface area, which facilitates sublimation and shortens drying times. Cutting or crushing larger pieces of material into smaller pieces can significantly increase sublimation drying speed and reduce operating costs.
4. Reducing the product charge thickness. While maintaining the same charge volume and equipment power consumption, appropriately increasing the drying shelf area can improve the shelf’s heat transfer capacity, shorten freezing and heating drying times, and reduce operating costs, but this will slightly increase equipment investment.