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木屑烘干机的干燥工艺!

2019-03-05 来源:http://www.zhongyanjixie.com 发布人:admin 浏览量:
  木材的干燥工艺是木材烘干机烘干木材的重要技术手段。直接影响着木材的品质与减少木材的损失。目前,国内常见的干燥工艺主要有常规干燥、高温干燥、除湿干燥、太阳能干燥、真空干燥、高频与微波干燥以及烟气干燥等。
  Wood drying technology is an important technical means of wood drying by wood dryer. It directly affects the quality of wood and reduces the loss of wood. At present, the common drying processes in China include conventional drying, high temperature drying, dehumidification drying, solar drying, vacuum drying, high frequency and microwave drying and flue gas drying.
  在上述的诸多干燥工艺中。常规干燥工艺是烘干机中常用的,也是历史悠久、技术成熟的干燥工艺。能够很好的保证每次的品质,对大型工业化干燥可以很好的实现。这也是常规干燥工艺被广泛应用的原因之一。
  Among the many drying processes mentioned above. Conventional drying process is commonly used in dryers, but also a long history, mature technology of drying process. It can guarantee the quality of each time and realize the large-scale industrial drying very well. This is one of the reasons why conventional drying technology is widely used.
  一、常规干燥工艺
  I. Conventional drying process
  常规干燥工艺是以常压湿空气作干燥介质,采用蒸汽、热水、炉气或热油作热媒等对空气间接进行加热。空气以对流的方式加热木材来达到干燥的目的。在上述的加热方法中又以蒸汽加热为主要加热方法。又称为蒸汽干燥。市场上的干燥机一般都会采用这种干燥工艺。
  Conventional drying process uses atmospheric pressure wet air as drying medium and steam, hot water, furnace gas or hot oil as heating medium to indirectly heat air. Air heats wood convectively for drying purposes. In the above heating methods, steam heating is the main heating method. Also known as steam drying. This drying process is commonly used in dryers on the market.
  二、高温干燥工艺
  2. High Temperature Drying Technology
  高温干燥与常规干燥的区别主要体现在木材干燥机中的干燥介质上。高温干燥的温度要比常规干燥的温度高很多。其干燥介质可以是湿空气,也可能是过热蒸汽。高温干燥的优点是干燥速度快、尺寸稳定性好、周期短,但高温干燥易产生干燥缺陷,材色变深,表面硬化,不易加工。
  The difference between high temperature drying and conventional drying is mainly reflected in the drying medium of wood dryer. The temperature of high temperature drying is much higher than that of conventional drying. The drying medium may be wet air or superheated steam. The advantages of high temperature drying are fast drying speed, good dimensional stability and short drying cycle. However, high temperature drying is prone to produce drying defects, darkening of material color, hardening of surface and difficult to process.
  三、太阳能干燥工艺
  3. Solar drying process
  太阳能干燥是利用太阳辐射的热能加热空气,利用热空气在集热器与材堆间循环来干燥木材。太阳能干燥一般有温室型和集热器型两种,前者将集热器与干燥室做成一体,后者将集热器与干燥室分开布置。集热器型的太阳能干燥室布置灵活,集热器面积可以很大,相应的干燥室容量也较温室型大。太阳能虽然是清洁的廉价能源,但它是受气候影响大的间歇能源,干燥周期长,单位材积的投资较大,故太阳能的推广受限。
  Solar drying is the use of solar radiation heat to heat the air, using hot air in the collector and wood heap cycle to dry wood. There are two types of solar drying: greenhouse type and collector type. The former integrates the collector and drying chamber, while the latter separates the collector and drying chamber. The solar drying chamber of collector type has flexible layout, large collector area and larger capacity than that of greenhouse type. Although solar energy is a clean and cheap energy, its promotion is limited due to its long drying cycle and large investment per unit volume.
木屑烘干机厂家
  四、真空干燥工艺
  IV. Vacuum drying process
  真空干燥是木材在大气压的条件下实施干燥,其干燥介质可以是湿空气,但多数是过热蒸汽。真空干燥时,木材内外的水蒸气压差增大,加快了木材内水分迁移速度,故其干燥速度明显高于常规干燥,通常比常规干燥快3-7倍。同时由于真空状态下水的沸点低,它可在不高的干燥温度下达到较高的干燥速率、干燥周期短、干燥质量好,特别适用于干燥厚的硬阔叶材。由于真空干燥系统复杂、投资大、电耗高,同时真空干燥容量一般比较小,否则难于维持真空度。
  Vacuum drying is the drying of wood at atmospheric pressure. The drying medium can be wet air, but most of them are superheated steam. In vacuum drying, the water vapor pressure difference inside and outside the wood increases, which accelerates the water migration speed inside the wood. Therefore, the drying speed is obviously higher than that of conventional drying, usually 3-7 times faster than that of conventional drying. At the same time, because of the low boiling point of water in vacuum, it can achieve higher drying rate, shorter drying period and better drying quality at low drying temperature, especially for hard hardwood with thick drying. Because of the complex vacuum drying system, large investment and high power consumption, and the vacuum drying capacity is generally small, otherwise it is difficult to maintain the vacuum.
  五、高频干燥工艺和微波干燥工艺
  High Frequency Drying Technology and Microwave Drying Technology
  高频干燥和微波干燥都是以湿木材作电介质,在交变电磁场的作用下使木材中的水分子高速频繁的转动,水分子之间发生摩擦而生热,使木材从内到外同时加热干燥。这两种干燥方法的特点是干燥速度快,木材内温度场均匀,残余应力小,干燥质量较好。高频与微波干燥的区别是前者的频率低、波长较长,对木材的穿透深度较深,适于干大断面的厚木材。微波干燥的频率比高频更高(又称超高频)但波长较短,其干燥效率比高频快,但木材的穿透深度不及高频干燥。
  High frequency drying and microwave drying are both based on wet wood as dielectric. Under the action of alternating electromagnetic field, water molecules in wood rotate frequently at high speed. Friction between water molecules generates heat, which makes wood heated and dried from inside to outside at the same time. The two drying methods are characterized by fast drying speed, uniform temperature field, small residual stress and good drying quality. The difference between high frequency drying and microwave drying is that the former has lower frequency, longer wavelength, deeper penetration depth, and is suitable for drying thick wood with large cross-section. The frequency of microwave drying is higher than that of high frequency (UHF), but the wavelength is shorter. The drying efficiency of microwave drying is faster than that of high frequency drying, but the penetration depth of wood is lower than that of high frequency drying.
  除上述干燥工艺之外还有一些其他的干燥工艺,比如红木产业中的蜡煮工艺,这个蜡煮工艺严格来说不完全是干燥工艺。它是木材干燥处理中稳定木性、防止开裂的一项工艺技术。不是每种木材都需要煮石蜡,石蜡的槽子不同,可以起到木材的干燥,但因为干燥的木材厚度、密度不同,所需要的槽子又不相同,所以在使用过程中的成本可能又会高一些。它目前在实木领域内的应用很少,因为技术难度相对高,仍在不断改良中。
  In addition to the above drying process, there are other drying processes, such as the wax boiling process in the mahogany industry, which is not strictly a drying process. It is a technology to stabilize wood property and prevent cracking in wood drying treatment. Not every kind of wood needs to be boiled with paraffin. The different grooves of paraffin can dry the wood. However, because the thickness and density of the dried wood are different, the grooves needed are different, so the cost in use may be higher. At present, it is seldom used in the field of solid wood, because the technical difficulty is relatively high, and it is still in the process of continuous improvement.
  以上内容由木屑烘干机厂家整理发布,更多相关资讯可以点击我们的官网进行咨询:http://www.zhongyanjixie.com
  The above content is organized and published by sawdust dryer manufacturers. For more information, please click on our official website to consult: http://www.zhongyanjixie.com.
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