The importance of microwave mahogany drying
Most of the waste of timber resources in China is due to the fact that wet materials have not been dried or treated improperly, resulting in the loss of wood and even the loss of use value. The purpose of wood drying treatment is to: (1) prevent deformation and cracking of wood; (2) improve the mechanical strength of wood and improve physical properties; (3) prevent wood from decaying; and (4) reduce the weight of wood.
As can be seen from the above, the responsibility of the wood drying industry is to improve the performance of the wood and improve its utilization. At the same time, since wood drying is the most energy-intensive process, drying operation is one of the key links in the production of wood products, both in terms of product quality and economic efficiency.
b) Current status of wood drying technology
1) The development potential of the wood drying industry is huge
According to the estimation of relevant experts, the annual drying capacity of China's existing equipment is about 4 million cubic meters, which accounts for only about 17% of the dry sawn timber in 2000, while the drying equipment capacity of the developed countries can reach 30% of the required drying capacity. The United States is as high as 60%. This shows that the capacity of China's drying equipment is far from that of developed countries and medium-developed countries. It also shows that the development potential of China's wood drying industry is great.
2) The drying energy consumption is high, and the pollution to the environment cannot be ignored.
Among the various drying equipments available in China, steam drying accounts for more than 80%. Furnace gas and direct-fired flue gas drying are more common in small businesses. Steam drying uses boilers as heating equipment. The average thermal efficiency of industrial boilers and their pipe networks in China is only 60%. At the same time, the heat loss of steam drying is large, accounting for 40% of steam heat energy. In addition, there are wall gates. Such as heat loss, so the primary energy utilization of steam drying is generally less than 30%. The high energy consumption of drying not only increases the cost of the product, but also increases the amount of smoke and exhaust gas discharged from the boiler and the drying chamber, thereby increasing the pollution of the harmful substances to the atmosphere. For example, a steam drying workshop with an annual drying capacity of 10,000 cubic meters is required to be equipped with a boiler of 4 tons/h. The harmful substances discharged per hour are: 40kg of soot, CO2: 1900 cubic meters, SO2 : 45 cubic meters, and a small amount of NO2, these substances are the main factors causing atmospheric greenhouse effect, acid rain and ozone destruction. According to relevant data reports, in the global monitoring network, Shenyang, Xi'an, Beijing, Shanghai and Guangzhou entered the top 10 in the ranking of the 40 most polluted cities. Since the contribution rate of energy to the link can reach 70%~80%, the energy-saving problem of wood drying must be paid attention to.