闭路循环热泵式流化床干燥过程研究
发布时间：2018-07-26 18:41
【摘要】：闭路循环干燥是指干燥介质在封闭系统中循环使用的干燥作业,具有可回收溶剂、安全、环保、产品质量好等显著特点。热泵是一种从低温热源吸收热量,在较高温度下放出大量可以被利用的热量的装置。热泵与闭路循环干燥的有机结合,不仅可回收干燥尾气中的大量热量,而且可节省大量用于冷却干燥尾气的冷量,节能效果显著,有广阔的应用前景。本文提出了以流化床为干燥器采用部分尾气循环的闭路循环热泵干燥流程;在分布板直径为188mm的流化床内,以PVC为干燥物料,以空气为流化、干燥介质,实验研究了进风温度和湿度对PVC流化干燥特性的影响,拟合得到了恒速段和降速段的干燥动力学模型分别为MR(28)a(10)bt和MR(28)exp(-ktn);用该模型计算了PVC流化干燥过程,对部分尾气循环的闭路循环热泵式流化床干燥过程进行了模拟分析,得到了循环比、热泵工质的蒸发温度、冷凝温度对干燥系统的COP、SMER的影响规律:蒸发温度20℃时,冷凝温度越高,干燥系统的C OP、SMER越小;冷凝温度105℃时,蒸发温度越高,干燥系统的C OP、SMER越大;蒸发温度20℃,冷凝温度75℃时,循环比增大,干燥系统的COP、SMER也越大。模拟计算的结果表明,在相同的操作条件下,与常规的闭路循环热泵式流化床干燥系统相比,部分尾气循环的闭路循环热泵式流化床干燥系统的SMER更高,节能效果显著。研究结果对促进闭路循环热泵干燥过程的工业应用有一定的理论和现实意义。
[Abstract]:Closed cycle drying refers to the drying operation in which the drying medium is recycled in the closed system. It has the remarkable characteristics of recoverable solvent, safety, environmental protection, good product quality and so on. Heat pump is a kind of device that absorbs heat from low temperature heat source and emits a large amount of heat which can be used at higher temperature. The organic combination of heat pump and closed loop drying can not only recover a lot of heat from the tail gas of drying, but also save a large amount of cooling for cooling and drying tail gas. In this paper, a closed circuit heat pump drying process using partial tail gas cycle in fluidized bed as dryer is proposed. In fluidized bed with diameter of distribution plate 188mm, PVC is used as drying material and air as fluidized medium. The effects of inlet air temperature and humidity on the drying characteristics of PVC fluidization were experimentally studied. The drying kinetics models of constant velocity section and low speed section were obtained as Mr (28) a (10) bt and Mr (28) exp (-ktn), respectively, and the drying process of PVC fluidized drying was calculated by this model. The drying process of closed circuit heat pump fluidized bed with partial tail gas cycle is simulated and analyzed. The effect of circulating ratio, evaporation temperature of heat pump working fluid and condensation temperature on COPSMER of drying system is obtained: the evaporation temperature is 20 鈩，
本文编号：2146942
[Abstract]:Closed cycle drying refers to the drying operation in which the drying medium is recycled in the closed system. It has the remarkable characteristics of recoverable solvent, safety, environmental protection, good product quality and so on. Heat pump is a kind of device that absorbs heat from low temperature heat source and emits a large amount of heat which can be used at higher temperature. The organic combination of heat pump and closed loop drying can not only recover a lot of heat from the tail gas of drying, but also save a large amount of cooling for cooling and drying tail gas. In this paper, a closed circuit heat pump drying process using partial tail gas cycle in fluidized bed as dryer is proposed. In fluidized bed with diameter of distribution plate 188mm, PVC is used as drying material and air as fluidized medium. The effects of inlet air temperature and humidity on the drying characteristics of PVC fluidization were experimentally studied. The drying kinetics models of constant velocity section and low speed section were obtained as Mr (28) a (10) bt and Mr (28) exp (-ktn), respectively, and the drying process of PVC fluidized drying was calculated by this model. The drying process of closed circuit heat pump fluidized bed with partial tail gas cycle is simulated and analyzed. The effect of circulating ratio, evaporation temperature of heat pump working fluid and condensation temperature on COPSMER of drying system is obtained: the evaporation temperature is 20 鈩，
本文编号：2146942
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