Wood Dring Method(二）
There are many ways to dry wood, how many do you know? There are Solar drying, Vacuum drying, Flue gas drying and so on.
Solar drying is to use the heat energy of solar radiation to heat the air, and use the hot air to circulate between the collector and the wood pile to dry the wood. Solar drying generally has two types: greenhouse type and collector type. The former integrates the collector and the drying chamber, and the latter separates the collector and the drying chamber. The collector-type solar drying room has a flexible layout, the collector area can be large, and the corresponding drying room capacity is also larger than that of the greenhouse type. Although solar energy is a clean and cheap energy source, it is an intermittent energy source that is greatly affected by the climate, with a long drying cycle and a large investment per unit volume, so the promotion of solar energy is limited.
Vacuum drying is the drying of wood under atmospheric pressure. The drying medium can be moist air, but most of them are superheated steam. During vacuum drying, the water vapor pressure difference between the inside and outside of the wood increases, which accelerates the speed of moisture migration in the wood, so the drying speed is significantly higher than that of conventional drying, usually 3-7 times faster than conventional drying. At the same time, due to the low boiling point of water in vacuum state, it can achieve high drying rate, short drying cycle and good drying quality at low drying temperature, especially suitable for drying thick hard broad-leaved wood. Because the vacuum drying system is complicated, the investment is large, the power consumption is high, and the vacuum drying capacity is generally small, otherwise it is difficult to maintain the vacuum degree.
Flue gas drying is the primary stage of conventional furnace gas drying, and generally refers to a small drying chamber built by soil method. The advantages are low investment and low drying cost. Its main disadvantage is that the smoke and dust pollutes the environment seriously, is prone to fire, and the drying quality is not easy to guarantee, which is very easy to cause losses.
