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微波技术在种子干燥方面的研究进展 总被引:2,自引:0,他引:2
干燥是种子加工的重要环节,微波干燥技术具有独特的优点和特点。近十几年来,国内外在种子微波干燥方面的研究取得了不少成果,而有关这方面的综述却未见报道。本文在阐述微波干燥机理和特点基础上,就近年来国内外微波技术在种子干燥方面的研究进展作一综述,并探讨微波技术在种子干燥方面的应用前景。 相似文献
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湿化学法是制备纳米材料的一种重要方法,但采用湿化学法制备的纳米粉体均存在干燥的过程,干燥方法的选择将对材料最终性能将产生明显的影响。微波干燥技术是最近发展而来的一种新型干燥技术,作者对几种微波干燥的模型以及微波干燥制备纳米粉体的进展作了说明。 相似文献
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阐述了联合干燥的定义和技术特点,介绍了各种联合干燥方式国内外的研究和应用现状,探讨了该技术在果蔬干燥加工中存在的问题和应用前景。 相似文献
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微波真空干燥技术现状 总被引:12,自引:0,他引:12
阐述了国内外微波真空于燥的研究现状,重点分析了脉冲微波真空干燥(间歇式微波干燥)的主要参数脉冲比、真空度、微波功率和能量效率。对微波真空于燥技术的发展提出了个人的看法。 相似文献
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Recent developments in physical field-based drying techniques for fruits and vegetables 总被引:1,自引:0,他引:1
AbstractModern physical field technologies mainly include microwave, radio frequency, infrared radiation, ultrasound, pulsed electric field, and so on. Nowadays, the application of physical field technology on conventional drying is one of the recent strategies to solve some problems in traditional drying. In this article, physical field-based drying techniques refer to hybrid drying methods consisting of the conventional heating combined with different physical field technologies, in which physical field technologies provide various heat sources differ from conventional ones. A review is presented of recent five-year literature in the development of selected physical field-based drying technologies (microwave, radio frequency, infrared radiation, and ultrasound) for fruits and vegetables. As shown by examples from the literature, these physical field-based drying techniques provide faster drying kinetics and better thermal efficiency and obtain dried products of improved quality (e.g. color, aroma, texture, and nutrition retention) relative to conventional hot air drying. The combination of these techniques and conventional hot air drying showed enhanced cost-effectiveness as well. Furthermore, recommendations are made for further research and development needs and opportunities in this area. 相似文献
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Osmotic dehydration (OD) is one of the conventional methods to increase the shelf-life of vegetables and fruits. However, the operating conditions can adversely affect the organoleptic and nutritional quality of fresh products due to the high sugar uptake during processing and the loss of water-soluble constituents to the osmotic medium. The application of edible films has attracted interest due to their ability to reduce the entry of solutes and simultaneously increase the removal of water during OD treatments. Microwave (MW) is one of the most effective emerging technologies to accelerate dehydration processes in vegetable matrices. This aspect is particularly relevant in strawberries, given its high content in bioactive and nutritional compounds. Thus, the aim of this paper was to assess the influence of edible film application (alginate–lactate) in strawberry slabs during combined OD-microwaves dehydration processes. Samples of 1?cm thickness were treated with sucrose solution (60°Bx, 40?°C, 4?h) and then were dehydrated in a microwave oven (1.2?W/g). The application of alginate–lactate edible films resulted in similar weight and water losses but lower solids gain compared to uncoated samples during OD treatment. OD pre-treated MW-dried strawberry slabs with moisture contents up to 0.15?kg dry basis were obtained after 100?min of MW drying. Besides, the effective diffusional coefficient (De) was estimated for MW drying process, values ranged from 4.5 to 8.8 10?10 m2/s when shrinkage effect was considered, and from 1.1 to 2.3 10?9 m2/s for constant thickness assumption. 相似文献
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Intermittent microwave convective drying (IMCD) is an advanced technology that improves both energy efficiency and food quality in drying. Modeling of IMCD is essential to understand the physics of this advanced drying process and to optimize the microwave power level and intermittency during drying. However, there is still a lack of modeling studies dedicated to IMCD. In this study, a mathematical model for IMCD was developed and validated with experimental data. The model showed that the interior temperature of the material was higher than the surface in IMCD, and that the temperatures fluctuated and redistributed due to the intermittency of the microwave power. This redistribution of temperature could significantly contribute to the improvement of product quality during IMCD. Limitations when using Lambert’s law for microwave heat generation were identified and discussed. 相似文献
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介绍了微波加热的基本原理、特点以及影响微波加热的因素,与蒸汽烘干、射频烘干相比,微波加热比蒸汽烘干节能40%,比射频烘干节能20%,仅每年运营维护费用比射频烘干节省4.5万元。提出应重点加强微波与物料间相互作用理论、微波场中物料的传热、传质机制,微波加热工艺与设备、微波加热技术与其它技术的有机结合等方面的研究。 相似文献
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阐述了微波干燥复肥的可行性,进行了微波干燥复肥的实验,得到微波干燥尿基复肥的失水曲线、温度曲线及养分曲线。同时作了60℃常规干燥的对比实验,表明微波干燥复肥能够达到有关标准,并远优于常规干燥。 相似文献
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介绍了应用微波加热烘干毛条的基本原理,研究了微波干燥设备的烘干效率、节能效果及烘干效果,结果表明,微波加热可以应用于纺织印染行业,为微波加热在纺织印染行业的推广应用提供了研究基础。通过生产应用,在计算微波加热毛条烘干工艺参数时,微波烘干机的干燥效率可取1.1kg/kW﹒h,微波干燥后,毛条含水率均匀,颜色前后色差无变化,纤维的强度和手感得到改善,微波干燥节能效果,比射频烘干节能约20%。 相似文献
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将微波干燥和热风干燥应用于新鲜金萱茶叶的干燥,在3个不同的微波功率(350 W,470 W,800 W)和4个不同的空气温度(70 ℃,80 ℃,90 ℃,100 ℃)下,研究了干燥参数即微波功率或温度对干燥时间、失水量的影响,同时还考察了茶叶中茶多酚总量和儿茶素含量的变化、干茶叶的复水性。实验得出,与热风干燥相比,微波干燥的时间缩短了76%~95%,而且干燥后的茶叶有很好的复水性,但干燥后茶多酚总量少于热风干燥;同时随着功率增加,微波干燥时间由11 min降为6 min,随着温度升高,热风干燥时间由127 min缩短为45 min。这两种方法的茶叶干燥动力学模型均满足Page’s半经验公式。 相似文献
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Ruifang WANG Zhanyong LI Yanhua LI Jingsheng YE 《Frontiers of Chemical Engineering in China》2009,3(3):289-292
A new hybrid drying technique by combining microwave and forced convection drying within a rotary drum, i.e., microwave rotary
drying, was developed with the purpose to improve the uniformity of microwave drying. In a laboratory microwave rotary dryer,
rewetted soybean was utilized as experimental material to study the effects of drum rotating speed, ventilation flow rate,
and specific microwave power on the drying kinetics and cracking ratio of soybean. It was found that, with rotation, the cracking
ratio can be lowered but without distinct improvement in the drying rate. Increasing ventilation flow rate and specific microwave
power can improve the drying rate, but the cracking ratio also increases as a negative result. The cracking ratio lower than
10% can be attained for ventilation flow rate lower than 2.0 m3·h−1 or specific microwave energy lower than 0.4 kW·kg−1 in the present experiments. 相似文献