梨片热泵干燥设备设计及干燥特性

Design of Heat Pump Drying Equipment and Drying Characteristics for Pear Slice

根据梨片热风干燥过程失水特性,设计满足批次处理50 kg新鲜梨片的热泵干燥设备,并对干燥系统性能及梨片干燥特性进行分析。通过对热泵干燥设备性能进行测试,表明干燥系统能够满足供热要求,温度和湿度在设定工艺下稳定运行,压缩机的蒸发和冷凝温度处于正常工作范围;热泵系统消耗单位能量所除去物料中的水分量(SEMR)为2.07 kg水/(kW·h),成本为1.37元/kg干果;梨片在热泵干燥过程中整体处于降速干燥阶段, Weibull分布函数能较好地拟合水分比和干燥时间的关系,尺度参数α为223.6 min,形状参数β大于1;通过对干燥室内不同位置梨片的总酚含量、抗氧化特性及颜色品质进行分析,表明产品品质较为均匀,干燥室内出风侧产品其抗氧化特性及颜色指标高于入风侧。

According to the drying characteristics of pear slice by hot-air drying,a heat pump drying system was devised,then 50 kg of pear slice was dried,the results showed that the drying equipment could provide sufficient heat and control temperature and humidity accurately,which could meet the demand of pear drying,and the evaporation and condensation temperatures of the compressor were within the normal working range.The value of SMER was 2.07 kg H2O/(k W·h),and the drying cost was 1.37 RMB/kg dried fruit.The Weibull distribution function could well fit the relationship between water ratio and the drying time,the scale parameter of α was 223.56 min,and the shape parameter of β was greater than 1.Through the analysis of the total phenols,antioxidant properties and color quality of pear slices at different positions in the drying room,it was shown that the product quality was relatively uniform,and the antioxidant properties and color indexes of products on the air-out side of the drying room were higher than those on the air-in side.