闭式热风循环密集烤房风冷热管冷凝除湿系统性能分析

Analysis on Performance of Air-cooled Heat Pipe Dehumidification System in Closed Hot Air Circulating Bulk Curing Barn

【目的】现行的密集烤房普遍采用开式除湿,一方面因排湿气流余热损失导致烤房的能量利用效率较低;另一方面,因烟叶烘烤过程中产生的香气成分及其它有益于提高烟叶烘烤品质的气体成分随排湿气流排至室外,导致烟叶烘烤品质降低。此项研究旨在提高烟叶烘烤品质及能源利用效率。【方法】基于闭式热风循环密集烤房冷凝除湿的方法,设计并搭建了一种以室外新风为自然冷源的闭式热风循环风冷式重力热管冷凝除湿装置,采用"七步式"烟叶密集烘烤工艺,测试分析了闭式热风循环风冷式重力热管冷凝除湿系统的除湿性能及烟叶提质性能。【结果】风冷式重力热管冷凝除湿系统的平均显热效率、潜热效率、全热效率分别为52.75%、21.23%、33.19%;系统的析湿系数在1.32~3.16;在排湿量最大的定色后期,系统的除湿负荷可达32.92 kg·h-1。与对照密集烤房相比,燃料消耗量降低0.57 kg·kg~(-1),烟叶烘烤成本降低0.48元·kg~(-1),烤后上等烟比例平均提高7.4%,中等烟比例降低2.2%,下等烟叶比例降低5.2%,烤后烟叶均价提高0.87元·kg~(-1)。【结论】闭式热风循环密集烤房风冷热管冷凝除湿系统能够对流出装烟室的排湿气流进行有效冷凝除湿,除湿、换热及节能性能良好,且烤后烟叶的提质增效效果显著。

【Objective】At present,open dehumidification is used in the bulk curing barn.On the one hand,the energy utilization efficiency of the bulk curing barn was low because of the waste heat loss of the dehumidifying air flow.On the other hand,the aroma components and other gas components which were beneficial to improve the quality of tobacco leaves were discharged into the outdoor with the dehumidifying air flow,which resulted in the decrease of the quality of tobacco curing.In order to improve the quality of tobacco leaf and energy utilization efficiency,an experimental study were carried out.【Method】A closed hot air cycle air-cooled gravity heat pipe condensing dehumidification device was designed and built based on the method of condensation and dehumidification in closed hot air circulation bulk curing barn.In this paper,the dehumidification performance of the condensing and dehumidifying system of air-cooled gravity heat pipe with closed hot air circulation and the properties of tobacco leaf quality were tested and analyzed by means of the‘Seven step’tobacco leaf bulk curing process.【Result】The experimental results showed that the average sensible heat efficiency,latent heat efficiency and total thermal efficiency of the air-cooled gravity heat pipe condensing and dehumidifying system were 52.75%,21.23%,33.19%,respectively.The Moisture evolution coefficient of the system was 1.32-3.16;The dehumidification load of the system could reach 32.92 kg·h-1 during later stage of color-fixing with the amount of dehumidification amount.Compared with the control bulk curing barn,the dehumidifying system decreased fuel consumption of 1 kg dry tobacco by 0.57 kg·kg-1,decreased cost of dry tobacco by 0.48 yuan·kg-1,increased the proportion of superi-or tobacco by 7.4%,decreased the proportion of moderate smoke by 2.2%after baking,decreased the proportion of inferior tobacco leaves by 5.2%,and the average price of tobacco leaf increased by 0.87 yuan·kg-1.【Conclusion】The condensing and dehumidifying system of air-cooled heat pipe in closed hot air circulating bulk curing barn could effectively condense and dehumidify the airflow from the smoke chamber,and had good performance in dehumidifi-cation,heat exchange and energy saving.Beside,it could ef-fectively improve the quality and economic benefits of roasted tobacco leaves.