2018年10月21日星期日

Wood microwave drying technology

2.1 the heating time is short and the drying speed is fast.
In the process of microwave heating and drying, wood is in the microwave field, heating is carried out on the whole section, that is, microwave heating has permeability, so that both inside and outside the wood can be heated at the same time, and the temperature rises at the same time. The moisture inside the wood rapidly vaporizes, forming the pressure of outward diffusion. However, due to the heat loss and evaporation of wood, the temperature inside the wood is higher.
microwave drying equipment
Surface temperature. When the internal temperature of wood is higher than 100 ~C, water vaporizes and produces vapor pressure, which accelerates the diffusion of water to the surface. The drying speed is fast and the drying efficiency is high. Compared with conventional heating drying, the heat of conventional heating drying is transmitted by conduction. From the surface to the inside, the direction of heat transfer is opposite to the direction of water evaporation, so the heating speed is slow and the efficiency is low. By contrast, natural drying takes months to years, hot air drying takes days to tens of days, and microwave drying takes only minutes to tens of minutes. The speed of microwave drying and the thermal conductivity of wood are not.
Off depends on the intensity of the microwave field, which depends on the size of the microwave power. The depth of microwave heating is related to the frequency of microwave. For the same frequency of electromagnetic wave, the heating depth is related to the moisture content and material quality of wood. 

没有评论:

发表评论