共查询到19条相似文献,搜索用时 79 毫秒
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箱式热泵循环干燥器 ,与传统的电热干燥箱相比 ,热效率较高 ,无环境污染问题 ,其平均单位能耗除湿量增加 1倍 ,耗电量降低 62 % ,投资回收期约为 1.5年。对凤尾菇进行干燥实验表明 :物料湿含量越高 ,平均单位能耗除湿量 SMER越大 ,系统给热系数 COP越高 ,节能效果越显著。 相似文献
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超声波在食品干燥中的应用 总被引:1,自引:0,他引:1
脱水食品的市场需求和质量要求越来越高,推动干燥新技术的发展。超声波干燥是一门新兴的干燥技术,可以在较低温度下更快地干燥食品,所以越来越受到人们的重视。文章首先介绍了超声波干燥的机理,然后论述了超声波预处理、超声热风干燥及超声喷雾干燥的研究现状、存在的问题和应用前景。 相似文献
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根据孤立系统热力学耦合原理,分析热泵干燥过程中存在的气液相变过程,揭示了相变过程中传热过程与传质过程之间的相互作用机制.分析得到,提高蒸发器的蒸发温度、降低冷凝器工质的冷凝温度,可以减少系统的熵产率.通过介绍干燥过程中水分汽化相变和迁移扩散中流与力的关系,得到热流和质流的线性唯象方程组,结合散度概念推导质量守恒方程和能... 相似文献
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A heat pump dryer using normal air, nitrogen, and carbon dioxide was selected to dry sliced West Indian ginger (Zingiber officinale Roscoe) rhizome (3 mm in thickness). The drying characteristics were compared with each other and inert gas heat pump drying showed an improved effective diffusivity. Quantities of the main pungent principle (6-gingerol) of ginger, extracted from these dried samples, were determined by high-pressure liquid chromatography (HPLC). The evaluation included dried samples obtained by heat pump, modified atmosphere heat pump, freeze drying, and vacuum drying. Retention of 6-gingerol increased in the order of normal air drying, freeze drying, nitrogen drying, carbon dioxide drying, and vacuum drying. From this point of view, inert gas also showed a better retention of flavor compared to most other types of drying. 相似文献
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热泵微波联合干燥系统研究 总被引:6,自引:0,他引:6
对热泵微波干燥的实用性及其性能进行了模拟分析和试验研究 ,试验及计算结果吻合较好。分析了空气旁通率、压缩机转速及空气质量流量等主要设计及运行参数对干燥性能的影响。与蒸汽加热干燥比较的结果表明 :通过精心设计热泵微波干燥系统 ,可使其能耗与蒸汽加热干燥相当。 相似文献
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热泵干燥技术研究现状及发展趋势 总被引:3,自引:0,他引:3
简单介绍了热泵干燥系统的工作原理。就国内外热泵干燥系统的理论、实验研究现状作了简单阐述。针对现状指出了热泵干燥技术的发展趋势。 相似文献
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Thin-layer drying experiments under controlled conditions were conducted for green sweet pepper in heat pump dryer at 30, 35, and 40°C and hot air dryer at 45°C with relative humidities ranging from 19 to 55%. The moisture content of sweet pepper slices reduced exponentially with drying time. As the temperature increased, the drying curve exhibited a steeper slope, thus exhibiting an increase in drying rate. Drying of green sweet pepper took place mainly under the falling-rate period. The Page equation was found to be better than the Lewis equation to describe the thin-layer drying of green sweet pepper with higher coefficient of determination and lower root mean square error. Drying in heat pump dryer at 40°C took less time with higher drying rate and specific moisture extraction rate as compared to hot air drying at 45°C due to lower relative humidity of the drying air in a heat pump dryer though the drying air temperature was less. The retention of total chlorophyll content and ascorbic acid content was observed to be more in heat pump–dried samples with higher rehydration ratios and sensory scores. The quality parameters showed a declining trend with increase in drying air temperature from 30 to 45°C. Keeping in view the energy consumption and quality attributes of dehydrated products, it is proposed to dry green sweet pepper at 35°C in heat pump dryer. 相似文献
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针对闭式热泵干燥系统非线性,强耦合等特点,将干燥循环分成升温过程和降温过程,并针对不同过程设计了相应的温度模糊控制策略。干燥过程温度、湿度是影响干燥物料品质的关键因素,为了提高干燥物料品质在温度控制的基础上设计了湿度模糊控制方案并给出了温湿度解耦策略。对温湿度的模糊控制效果进行了实验检测。系统运行结果表明:温湿度控制效果显著,温度的偏差控制在±0.8℃,湿度的偏差控制在±3%RH。 相似文献