In the quest for more efficient and cost-effective drying processes, a groundbreaking study published in *Zhileng xuebao* (Journal of Refrigeration) has shed new light on the drying characteristics of industrial iron powder under low-temperature and low-pressure conditions. Led by Zhang Ruhang, the research explores the intricate dynamics of heat and mass transfer, offering promising insights for the energy sector.
The study utilized a custom-built low-temperature and low-pressure heat pump drying device to investigate the drying effects of industrial iron powder at varying low pressures. The findings are nothing short of transformative. “A decrease in the drying ambient pressure can significantly increase the dehumidification capacity of wet iron powder,” Zhang Ruhang explains. The data reveals that when the ambient pressure drops from 101 kPa to 10 kPa, the dehumidification capacity increases by a staggering 2.5 times, reducing the moisture content of iron powder to less than 1% at the lower pressure.
The implications for the energy sector are profound. Traditional drying methods often consume substantial energy, making them costly and environmentally taxing. By leveraging low-pressure environments, industries could achieve more efficient drying processes, leading to significant energy savings and reduced operational costs. “The mass and heat transfer coefficients decrease as the pressure decreases, but the Lewis factor, which characterizes the relative intensity of heat and mass transfer, increases with the ambient pressure decrease,” Zhang Ruhang notes. This means that in a low-pressure environment, the relative efficiency of heat and mass transfer improves, making the process more effective.
The study also examined the impact of air speed on the drying process. In a drying environment of 10 kPa and 50 °C, increasing the air speed from 0.2 m/s to 2 m/s resulted in a 32.9% increase in the mass transfer coefficient and a 67.8% increase in the heat transfer coefficient. However, the enhanced effect of air speed on the mass transfer coefficient is somewhat inhibited by the low-pressure environment, leading to an increase in the Lewis factor with the increase in air speed. “The Lewis factor is 0.5–0.6 in an environment of 10 kPa, indicating obvious differences between the mass diffusion and heat diffusion in a low-pressure environment,” Zhang Ruhang adds.
This research, published in *Zhileng xuebao*, which translates to the Journal of Refrigeration, opens new avenues for innovation in the energy sector. By optimizing drying processes through low-pressure and low-temperature conditions, industries can achieve greater efficiency and sustainability. The findings suggest that future developments in drying technology could focus on harnessing low-pressure environments to enhance heat and mass transfer, ultimately leading to more energy-efficient and cost-effective solutions. As the energy sector continues to evolve, this research provides a crucial stepping stone towards a more sustainable and efficient future.