Investigation of mass transfer, thermodynamics, and greenhouse gases properties in pennyroyal drying

Kaveh, Mohammad; Karami, Hamed; Jahanbakhshi, Ahmad


In this research, kinetic analysis, energy, exergy, and greenhouse gases of a hybrid laboratory dryer (solar-hot air) are presented for pennyroyal. Drying was performed at input temperatures of 50, 60, and 70°C and air velocities of 0.6, 1.2, and 1.8 m/s. The effect of drying variables on moisture ratio, effective moisture diffusivity, specific energy consumption, energy utilization ratio, energy utilization, exergy efficiency, and exergy loss was investigated. The highest amounts of effective moisture diffusivity and specific energy consumption were 2.30 × 10−10 m2/s and 48.60 kWh/kg, respectively. Energy utilization and energy utilization ratio varied from 0.0064 to 0.0826 kJ/s and from 0.056 to 0.957, respectively. Exergy loss and exergy efficiency varied between 0.0037 to 0.0510 kJ/s and 0.2428 to 0.8731, respectively. In addition, by increasing the temperature and intake air velocity, drying rate increased and the emissions of greenhouse gases (CO2, SO2, and NOX) were reduced. Practical Applications: Modeling of the drying process is an important aspect of drying technology, especially in drying for industrial purposes. The aim of modeling is to select the most suitable drying method and the best operating conditions for obtaining the product. Some of the key issues in drying have been to reduce the price of the energy resources used, increase the drying efficiency, and improve the quality of the dried products. The concept of exergy is defined by the concept of reversible work. The concept of reversibility depends on energy balance and mass regardless of energy quality (exergy loss).