Selection of Wood Drying Methods

1. Steam heating for drying. This method has the following advantages: ① easy adjustment and control of temperature and humidity, and adjustable humidity treatment, ensuring the quality of drying; ② Mature technology, easy operation, capable of implementing automated or semi automated operations, facilitating centralized and unified management; ③ The equipment has good performance and a long service life; ④ The drying room has a large capacity, good energy-saving effect, and moderate or low drying cost; Coal or waste wood can be used as fuel. The disadvantage is that it requires a steam boiler. Therefore, steam heating drying is a wood drying method used by large and medium-sized enterprises both domestically and internationally. Enterprises with large production capacity and existing steam supply are suitable for using steam drying; Small and medium-sized enterprises with high requirements for drying quality and a monthly drying capacity of no less than 300m3 of sawn timber should generally consider steam drying.

Overheated steam drying should be used with caution. Only when the drying needle leaf material is thin and the requirements for drying quality are not high, can it be used.

2. Heating wood with furnace gas for drying. The main advantage of this method is that it does not require a boiler and uses the processing residues from the factory& mdash; Wood waste is used as fuel, with low drying costs. The disadvantage is that the temperature and humidity state of the drying medium are difficult to adjust and control, requiring high operational skills and responsibility, and relatively high labor intensity. The reliability and reasonable design of such equipment are closely related. Unreasonable design; Earth Room”, Uneven drying and long duration. Quality is not guaranteed, and it is also prone to fire.

Furnace gas heating and drying are suitable for small and medium-sized enterprises without steam supply, with small drying capacity, and a large amount of wood waste as fuel.

3. Dehumidification and drying method. Its advantage is that it can recover the latent heat of vaporization released by the condensation of humid air, which means that this method has almost no or only a small amount of waste gas heat loss, and the process is simple, the operation is easy, the drying is safe, and generally does not cause wood damage. The disadvantage is that the drying temperature is low (low temperature dehumidification can reach 50 ℃, medium temperature dehumidification can reach 60 ℃, and some high temperature dehumidification and drying can even reach room temperature of 80 ℃), the drying time is long, and for thick or difficult to dry materials, it is difficult to dry completely, and the drying cost is high due to the main use of electricity.

Dehumidification and drying are used in small enterprises with low production, or in places where the environment is inconvenient for building boilers or gas combustion furnaces, or where there is sufficient electricity supply and electricity prices are relatively cheap.

4. Other drying methods. Methods such as solar drying, microwave drying, and high-frequency drying are only suitable for certain special occasions or industries with low drying capacity and high quality requirements.