乳品行业低温余热回收系统性能分析

针对乳品行业排风风量大但品位低的特点,本文提出利用排风余热代替蒸汽来预热干燥空气的余热回收系统.在构建预热器、回热器和主加热器等部件热量流模型的基础上,建立了不包含中间节点参数的系统整体热量流模型.结合某奶粉厂运行数据对模型进行求解,结果表明,该系统将排风温度由90℃降低到42.58℃.在给定热负荷下,通过匹配中间回路...

Performance Analysis of the Low-temperature Waste Heat Recovery System for the Dairy Production Industry

Applying the waste heat recovery technique can improve the energy utilization of system obviously. This paper proposes a waste heat recovery system for the dairy production industry,which using the low-grade but large quantity exhaust air instead of the steam to preheat the drying air. Using the heat current method builds the models of preheater, regenerator and core heater respectively. Then applying the thermal-electrical analogy method and Kirchhoff’s law builds the equivalent thermal resistance network and global heat transfer constraints, which consists no intermediate parameters. Based on the actual operating data of a milk powder plant, solving the model shows that the waste heat recovery system can replace the steam-based preheater and decrease the temperature of exhaust air from 90℃ to 42.58℃. Discussions under the condition of the constant mass flow rate of steam of core heater shows the negative relationship between the mass flow rate of intermediate loop and temperature of inlet air and the temperature of drying air may exceed 200℃.Then to avoid overheating the drying air, the mass flow rate of steam of core heater, the mass flow rate of intermediate loop and temperature of inlet air are matched under the given heat load. It provides useful operating guidance for waste heat recovery system and core heating system based on the mass flow rate of intermediate loop or temperature of inlet air respectively to reduce the overall energy consumption.