共查询到19条相似文献,搜索用时 140 毫秒
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微波技术以其独特的加热机理和特点为木材快速高效干燥提供了一条新途径。笔者简述了近年来国内外在木材微波干燥工艺方面取得的一些重要的研究进展,主要集中在微波功率、含水率和温度等基本干燥参数的优化及红外摄像技术等先进检测技术的应用等方面。同时指出了在木材微波干燥基础理论、干燥工艺、木材结构特性与微波加热非均匀性等方面缺乏系统性研究的问题。建议今后应加强基础理论研究并结合现代测控技术进行系统研究。 相似文献
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概述了微波技术在我国木材干燥、木材改性、胶粘剂合成、材料缺陷检测、竹木产品含水率检测和人造板甲醛释放量检测方面的研究成果及应用现状,微波干燥技术使木材在干燥过程中温度梯度和含水率梯度较小,具有加热时间短、干燥质量好、提高出材率等优点;通过微波改性技术,可以赋予竹木材某些特殊的功能,使低档竹木材高档化,从而有效地利用竹木材料,提高经济价值;借助微波技术进行胶粘剂合成,反应速度比传统的加热方法快数十倍;提出了微波技术在木材干燥、木材改性、无损检测、萃取甲醛释放量检测的发展方向和应用前景. 相似文献
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微波干燥技术在竹制品生产中的应用 总被引:1,自引:0,他引:1
微波干燥技术在竹制品生产中的应用刘昌铎微波可以对木材及胶合板等木质材料进行快速、高效的干燥处理,同样也能对竹制品进行干燥、杀虫、防霉处理。南京七七二厂微波研究所通过反复的试验,已成功地设计和制造了相应的微波干燥设备。本文介绍新研制的用于竹席干燥的特大... 相似文献
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微波干燥胶清橡胶试验研究 总被引:3,自引:0,他引:3
通过微波加热干燥胶清胶的工艺试验,结果表明:微波功率、辐射时间和物料质量对脱水率有显著的影响;微波干燥胶清胶技术有干燥时间短、干燥效率高的特点,可用于胶清胶的生产工艺。 相似文献
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木材微波干燥技术与应用 总被引:1,自引:0,他引:1
1木材微波干燥的原理木材微波干燥是以湿木材作为电介质,放置于微波电磁场中,在频繁交变的电磁场作用下,使木材中水分子极化,极化水分子迅速旋转,相互摩擦,产生热量,从而加热和干燥木材。湿木料在微波电磁场中吸收的电功率可表示为:p=0.55fE2εtgδ10-12式中:p—单位体积木材吸收的电功率;f—电流频率;E—电场强度;ε—木材的介电系数;tgδ—木材损耗角正切。由上式可以看出,电场强度E越大,电流频率f越高,木材吸收的电功率就越多。这是因为电场越强,极化的水分子摆动的振幅越大,摩擦产生的热量就越多。但过高的电场强度,容易使木材击穿,这… 相似文献
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竹笋膳食纤维微波干燥特性及其功能特性 总被引:2,自引:0,他引:2
探讨微波干燥特性和干燥工艺条件(干燥功率、排湿风速、加热时间间隔比和漂白时间)对膳食纤维持水率、持油率、能耗和白度的影响.结果表明:膳食纤维微波干燥主要处于降速阶段,其动力学过程可以用指数模型描述;不同微波干燥工艺条件和漂白时间对膳食纤维功能特性、能耗和白度有显著性影响;随微波干燥功率的增加和漂白时间的延长,膳食纤维的持水率和持油率下降;微波干燥能耗随微波功率和排湿风速的增大而增大,随漂白时间的延长而逐渐下降,随加热时间间隔比的增加而减小. 相似文献
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综合利用烟杆废料制取优质活性炭 总被引:6,自引:1,他引:5
研究了以烟杆废料为原料,在微波辐照和传统加热下氯化锌法制取活性炭的方法.经对比实验得出,用微波辐照9min即可完成传统工艺中预热、干燥、炭化和活化4个阶段,活性炭产品的亚甲基监脱色力为170mL/g,微波辐照工艺的加热时间仅为传统工艺的1/20;用传统加热方法,炭化温度680℃,炭化时间1h,活化温度800℃,活化时间2h,活性炭的亚甲基蓝脱色力为150mL/g。2种方法制得的活性炭的亚甲基蓝脱色力均超过国家标准一级产品的指标(120mL/g)。 相似文献
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微波和对流联合干燥的试验研究 总被引:1,自引:0,他引:1
试验以速生杨树和马尾松为干燥对象,研究了传统的对流干燥、微波干燥及微波和对流联合干燥三种不同供热方式的干燥动力学规律。结果表明:在整个干燥过程中,微波和对流联合干燥能使木材的内、外层含水率分布保持一致;与传统的对流干燥相比,联合干燥可以改善木材质量,提高干燥速度,降低干燥能耗。 相似文献
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为给鲜花椒微波烘干效果的研究和花椒微波烘干机的研制奠定基础,分别利用小型平板层式微波炉及自制大型微波炉对鲜花椒进行了间断式和连续式烘干试验。试验结果表明:无论采用旋转式微波炉还是平板层式微波炉,烘干时间均随鲜花椒投料量的增加而延长,干燥后花椒香味降低;填料约700 g,以小型旋转式微波炉和平板层式微波炉烘干所用时间分别约为44、62 min,前者的烘干效率比后者提高20.48%;鲜花椒在旋转式微波炉中水分蒸散过程表现为抛物线型,在烘干过程中花椒种子集中脱出,烘干效率高,但其在平板层式微波炉中水分蒸散过程呈缓慢降低的斜线型,种子在烘干过程的最后阶段才脱出,烘干效率低;以自制大型微波炉烘干,填料3.45 kg,最佳加热上限温度和运行温度分别为55℃和41~50℃,加热—除湿循环中加热8 min、除湿90 s,烘干时间为45 min,较以小型平板层式微波炉烘干所用时间缩短29%。研究结果还表明:以微波炉烘干鲜花椒,可极大地缩短鲜花椒的干燥时间;以自制大型微波炉烘干鲜花椒,最大填料量约8 kg,可以满足农户对小批量鲜花椒的烘干要求。 相似文献
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Tomy Listyanto Keisuke Ando Hidefumi Yamauchi Nobuaki Hattori 《Journal of Wood Science》2013,59(4):282-289
To investigate the effect of CO2 laser incising under five drying methods on drying characteristics of Sugi lumber, the squares (120 mm × 120 mm) of Sugi lumber with length of 650 mm were used. A half of samples were incised by CO2 laser with incising density of 2,500 holes/m2. Five types of drying methods were used: microwave drying, steam injection drying, and three combinations of microwave heating and steam injection drying. Steam injection drying was conducted by injecting superheated steam of 120 °C through a perforated plate heated to 140 °C of an injection press. Microwave was irradiated with the power of 3 kW at frequency of 2.45 GHz. The results indicated that incising helps heat through a specimen and thus the whole temperature raised rapidly, which was up to threefolds compared to that of no-incised one. Incised specimens dried by a combination of microwave heating for 1 h and steam injection showed the highest drying rate, which was up to 5.3 %/h. Incising and microwave heating contributed positively to dry lumber under more uniform distribution of moisture content and to reduce surface and internal checks. Incised specimen dried by microwave showed the most uniform distribution of moisture content without surface and internal checks. 相似文献
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A microwave applicator for on line wood drying: Temperature and moisture distribution in wood 总被引:7,自引:0,他引:7
Summary An especially designed open microwave applicator was analysed using wood as the material to be heated and dried. The idea
was to develop an on line microwave construction consisting of several small open applicators, each fed by a small standard
magnetron (for example 1.4 kW main power). The process was analysed by measuring the wood temperature during heating using
an IR-camera and detecting the moisture distribution during drying by CT-scanning. Pine and birch wood samples were used in
the experiments, mainly 40 mm in thickness. The experiments show that the power distribution differs between dry wood and
moist wood. The analysis of the temperature fields captured by the IR-camera during the first minutes allows a rather accurate
determination of the MW power. Consequently, the drying proceeds unevenly in the wood specimens, especially in the longitudinal
direction. The dimensions of the applicator and its relation to the wood dimension are very important. However, the wood was
not destroyed, the temperature and moisture gradients did not affect the wood in terms of checks or deformations. The drying
rate in different positions of the specimen varied between 0.30 and 0.80 percentage moisture content/min. The uneven energy,
meaning temperature and field distribution, is to be compensated in the future by a moving wood load and by alternating the
position of each applicator in a larger scale microwave pilot plant.
Received 25 February 1997 相似文献
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介绍了微波加热原理及微波加热特性,进行了微波加热除冰实验.结果表明,微波除冰可以达到使路面与冰面分离的效果. 相似文献