Study On The Drying Characteristics And Technologies Of Russian Larch Wood With Thickness Of 30mm

In this paper basing on the Russia larch wood as research material with thickness of 30 mm, the drying Characteristics and Technologies were studied and the recent existing drying problems were discussed and analyzed as well. Firstly we study the changes of wood characteristics when larch lumbers were dried to different moisture content level under different temperature, analyses the influence to wood characteristics and drying quality caused by temperature and moisture content. Then by inspecting distribution of temperature and moisture content in wood we study the change law of temperature and moisture content distribution during the conventional drying, discuss the relationship between temperature and moisture content. According to the experiment results combining with the putative drying schedule from 100°C drying test and local larch drying experience, four kilns larch wood were experimented with increasing and decreasing schedules. By analyzing the parameters during drying process such as temperature, moisture content, stress and humidity of kiln air, quoting the law of mass and heat transfer, at last the feasible drying schedule for Russia larch wood were developed, the effective measures to improve the drying quality and drying efficiency were presented meanwhile the basic theory for establishing drying schedule was drawn after the experiments. Furthermore, we study the influence to wood characteristics and drying characteristics of larch which were pre-treated by microwave radio and steam in order to discovery a new way to larch drying.The results show that in middle and low zone of drying temperature the mechanical property behave the tendency of reducing while in high-temperature zone the property reducing obviously; Temperature gradient promotes transfer of moisture in larch lumbers, but should form and maintain long time temperature gradient to accelerate drying rate through proper schedule; suitable moisture content gradient can accelerate the drying rate; the schedule developed from 100°C drying test applied in conventional kiln is suitable for 30mm thickness Russia larch wood, but can not apply hard drying medium in initial stage, the treatment opportunity of heat and wet need advancing; the decreasing temperature schedule is feasible for Russia larch wood drying, but should choose correct opportunity of temperature decreasing; microwave radio treatment can improve the drying rate obviously but resulted in some micro-structure changes and certain mechanical properties reducing; steam treatment improve the Characteristics of heat transfer and drying rate, has little influence to wood bending strength and modulus of elasticity.