关键词: 关键词：湿空气, 空气干燥, 有机朗肯循环, 系统集成, 废热回收

Abstract: Air drying is one of the widely used farm products process technologies. Due to the thermal-sensitivity performances of the farm products, the low operation temperature makes waste heat recovery from the drying chamber exhaust wet air become difficult, and the conventional open air-drying process is energy consumption. A novel closed air drying system is proposed through integrating the top air drying cycle and a bottom organic Rankine cycle (ORC). After verified the mathematical model of the wet air waste heat recovery through the wet air condenser, condensed water mass flow rate and the energy saving characteristics of the proposed system were investigated through analyzing the key parameter influences on the overall performance indices. The results showed that under the operation condition in this study, compared to the wet air inlet temperature and mass flow rate, increasing the relative moisture content in the wet air improved the condensed water mass flow rate and heat exchanged substantially. Also the maximal value of mass flow rate of condensed water was obtained with the optimal wet air mass flow rate at 0.10~0.15 kg/s. The overall net power output of the system increased prominently as both the dew point temperature of the drying cabin outlet wet air and the evaporation temperature of the bottom ORC increased. Therefore, for the conventional heat-sensitive farm products drying process, the low drying temperature and high dew point temperature for the wet air at drying chamber outlet, and the evaporation temperature at 313~323 K of the ORC were recommended.

Key words: Key words: Wet air, air drying, Organic Rankine cycle, system integration, waste heat recovery