微波真空干燥技术现状

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。     

微波真空干燥技术的探讨

干燥是高能耗行业,我国干燥能耗约占全部工业能耗的12％。“节能减排”是保障我国能源安全、发展经济和保护环境的基本国策。根据不同的生产条件,科学选用烘干工艺和设备,对节约能源、减少原材料消耗、降低生产成本、提高经济效益、增强企业市场竞争力具有重要的意义。     

微波真空组合干燥技术的研究

微波真空干燥是综合微波干燥和真空干燥各自优点的一项新技术,将微波干燥的快速高效性和真空干燥的低温高质相结合,在真空条件下利用微波对物料进行干燥处理,从而实现物料的快速低温干燥。着重阐述了微波真空组合干燥技术的机理、特点、干燥动力学以及影响微波真空干燥的重要因素,并对微波真空组合干燥的应用研究进行了介绍。     

微波真空干燥高粘度的灵芝浓缩液

热敏性、高粘度物料的干燥仍是现代干燥技术中的一个难题。灵芝水提后，由薄膜蒸发器浓缩至含水量70％左右，然后采用微波真空干燥（真空度3000Pa）至水分含量10％左右，改用传统的电热真空干燥（55～60℃）至含水量6％～7％。对干燥产品的主要生物活性成分——灵芝多糖和三萜酸进行了分析检测并与其它干燥方法进行了比较。结果表明：利用微波真空干燥的灵芝产品其灵芝多糖和三萜酸的保留率与冷冻干燥产品十分接近。而比传统真空干燥（60—65℃）的产品要高得多，此外采用微波真空干燥的干燥时间要短得多。     

胡萝卜微波真空干燥试验研究

以胡萝卜为原料，采用均匀设计对微波真空干燥的微波功率、干燥温度及料层厚度进行试验研究，分析各试验条件下的水分含量及胡萝卜素含量，得到了干燥曲线和胡萝卜素保有量曲线，得出了胡萝卜失水量、胡萝卜素含量与各因素之间的回归方程，可用于描述胡萝卜的微波真空干燥特性。     

微波及辐射真空干燥过程中的干燥动力学及能量消耗

The general objective of this work is to analyze energy input in a vacuum process with the incorporation of microwave heating. Thus, necessary criteria for designing an efficient freeze-drying operation are considered through the analysis of strategies based on the combination of different intensities of raxiiant and microwave heating.The other aim of this research topic is to study the kinetics of drying in relation to mass transfer parameters.Five freeze-drying strategies using both heating systems were used. Consequently, energy input could be related to diffusivity coefficients, temperature and pressure profiles during dehydration of the product and analyzed in comparison to a conventional freeze-drying process.     

微波真空组合干燥果蔬的研究

本文论述了微波真空组合干燥的基本原理及干燥特点,剖析了国内外微波真空组合干燥果蔬的研究进展情况,探讨了影响微波真空干燥果蔬品质的主要因素及应用前景。     

胡萝卜在不同功率模式下的微波真空干燥

试验采用微波真空干燥方法,在连续、间歇、连续与间歇组合的3种微波功率输出模式下,对胡萝卜丁进行干燥试验。分别采用不同压力（5．1kPa、11．9kPa、18．3kPa）、不同功率密度（1．0W／g、1．5W／g、2．0W／g）、同一开断周期（120s）的不同微波开断时间（90s-on／30s-oft．60s-on／60s-off．30s-on／90s-oy）对产品温度和干燥速率的影响进行研究。在此基础上,提出了在2．0W／g、5．1kPa条件下,1h连续与2h间歇（90s-on／30s-off）的组合模式,并比较了3种模式下的产品温度、干燥速率和能量利用率。试验结果显示,压力、微波功率密度、微波开断时间之比均对产品温度和干燥速率有影响,其中功率密度是最主要的影响因素。在3种模式中,1h连续与2h间歇的组合模式产品温度较低,能量利用率较高。     

黑加仑真空冷冻与微波真空联合干燥工艺研究

以黑加仑为原料,对其进行了真空冷冻与微波真空联合干燥工艺的研究。结果表明：先真空冷冻后微波真空干燥（FDMV）的组合方式是可行的;联合干燥合理工艺参数为：微波功率1．34kW。绝对压力11kPa,转换含水率为20％（wb）;通过试验验证,联合干燥生产的脱水黑加仑的感官品质和营养成分接近真空冷冻干燥,联合干燥方式对节省干燥时间和降低能耗是有效的。     

微波真空干燥法生产无水氯化亚锡的研究

以微波真空干燥的方法来生产无水氯化亚锡,操作安全简单,无废料,经济效益明显。生产出的无水氯化亚锡含量高、浊度低、品质优良,主含量大于99.3%,铁含量低于70 mg/kg,浊度可控制在10 NTU以下。     

干燥技术的进展和应用

文章侧重与化学工业关系较密切的方面，以各种干燥机的开发、改进和应用为主要线索，简要评述干燥技术２０多年来的进展与应用、技术发展趋势和存在的问题、以及我国的基本情况。     

Nonstationary convective drying of raspberries,assisted by microwaves and ultrasound

This study was conducted to investigate the drying characteristics and quality of raspberries dried in non-stationary conditions. Seven drying programs were carried out, including convective (CV) drying as a reference. The non-stationary-hybrid programs were based on continuous CV drying with intermittent microwave and ultrasound assistance. The Midilli–Kucuk model was used successfully to describe the drying kinetics of raspberry fruits. The comparison between moisture ratio, drying rate, diffusion coefficient, energy consumption, and quality analysis, showed that non-stationary-hybrid drying improves process kinetics and results in less color change, higher anthocyanin retention, and better texture profile analysis characteristics with optimal energy usage than other methods. In addition, the physical and microstructural changes occurred during different drying processes were discussed.     

维多利亚褐煤干燥气化技术进展

为实现褐煤清洁高效利用,在分析维多利亚褐煤煤质特性的基础上,综述了国外先进的褐煤干燥及气化技术。褐煤干燥工艺主要有蒸发干燥和非蒸发脱水2种,重点分析了磨煤机干燥工艺、褐煤浆生产高致密褐煤球干燥工艺、回转蒸汽管干燥工艺和机械热挤压脱水工艺的工艺流程和应用现状,其中磨煤机干燥工艺和回转蒸汽管干燥工艺技术比较成熟,工业应用较多。论述了维多利亚褐煤气化工艺中的褐煤集成干燥气化工艺和增压流化床气化工艺,提出若将褐煤集成干燥气化工艺中的空气气化改为富氧或纯氧气化,并通入一定比例水蒸气,该工艺有望应用于中国煤化工领域,生产化工合成原料气,为中国褐煤高效洁净利用提供途径。     

氯化氢干燥工艺比较

介绍三氯氢硅合成原料氯化氢的3种干燥方法(深冷干燥法、浓硫酸干燥法、四氯化硅水解干燥法),并指出这3种干燥工艺的优缺点。     

典型褐煤干燥技术比较

分析了国内外典型褐煤干燥技术的原理、关键参数、技术特点等,并从技术适应性、工艺条件、干燥效果、环境影响等方面进行综合评价比较。结果表明:美国K-Fuel工艺要求入炉粒度较其它技术大,适应性稍差;褐煤提质后均可作为锅炉燃料。干燥温度越高,褐煤干燥效果越好。德国泽玛克管式干燥成型技术、美国K-Fuel工艺为带压干燥,其他工艺为常压工艺。5种工艺可降低水分7.0%～25.0%,增加热值3.24～5.94kJ/g;澳大利亚BCB工艺、神华HPU-06工艺、德国泽玛克管式干燥成型技术产品为型煤,规格可调;其他工艺产品粒度变小。神州干燥-干选联合工艺回吸可能性大、自燃特性改善不明显,其余工艺深度脱水后可防止自燃,不易回吸。5种工艺污染物排放均较为简单,对环境影响较小。     

新型抗菌技术及产品

现在,虽然科学家们有将抗菌产品与嵌段共聚物结合应用的设想,但人们仍需重视此技术在涂层类产品上的应用问题。     

改善PVC干燥系统 提高产品质量

介绍了PVC干燥系统的设备、工艺改造情况。通过改造,减少了落底料,提高了产品合格率。     

Optimization of the process of drying of corn seeds with the use of microwaves

Abstract

The heating and drying of various types of food using microwave improve the economy of time and energy. The physiological quality variation of the seeds submitted to microwave drying is known to some extent. In this context, some authors have reported excellent performance using this technique, on germination rates, after drying. The commercial use of microwave drying in seeds is irrelevant, which motivates more extensive research on the benefits and challenges of this technique that can increase its insertion in the post-harvest handling steps of agricultural products. Corn is a product of high worldwide relevance. Therefore, the use of microwaves in its drying process has excellent potential to arrive at significant savings in its production. Thus, this study is aimed to evaluate the effects on the physiological quality of the seeds submitted to different drying conditions, using the microwave radiation. To that end, corn seeds, with a water content of 20% on wet basis (w.b.), were dried at 40, 50, and 60?°C, at power ratings of 0, 0.6, and 1.2?W/g; in the vacuum condition. Drying occurred continuously, with intermittent power, until the seeds reached the 12% wet basis; in this condition, the seeds could be stored with secure. Germination tests performed shortly after drying showed that the temperature of 40?°C at a power of 0.6?W/g had a reduction in drying time of approximately 5?h when compared to conventional drying (40?°C and 0.0?W/g). The evaluation of the physiological quality of the seeds showed no significant difference in the germination, vigor, and longevity indices of the treated seeds.     

活性炭负载醋酸锌催化剂真空干燥的特性

通过真空干燥实验研究了供热温度、真空度、料层厚度等因素对醋酸锌-活性炭催化剂干燥规律的影响。实验结果表明:醋酸锌-活性炭催化剂采用真空干燥可以实现快速低温干燥;催化剂的干燥只有降速干燥阶段,而没有常速干燥阶段;供热温度的提高有助于提高干燥速率,但温度超过80℃时催化剂出现轻微粉化;真空度越高,干燥速率特别是初始干燥速率越快;料层厚度的增加,使干燥时间延长,但设备的干燥强度有所提高。正交实验得出,在多因素条件下,温度对干燥强度的影响最大,其次是真空度和料层厚度。