Study On Structure,chemical And Thermodynamic Characteristics Of Ancient Buried Quercus Wood

Ancient buried wood isalso known as "Oriental god wood" and "millennium ebony" in the world,and is popular with people because of its high density,high strength and dark color.In recent years,the amount of ancient buried wood is increasing,but the research on it mainly focuses on anatomical characteristics,tree species identification,drying characteristics and so on,which are sill in the initial stage of ancient buried wood research..In order to make good use of ancient buried wood,the paper studied structural characteristics,chemical characteristics,pyrolysis characteristics and thermal stability of Quercus ancient buried wood,so as to provide theoretical basis for studying of ancient buried wood.The experimental results are as follows:(1)Compared with the contrast samples of modern wood,the basic structure of Quercus ancient buried wood did not change significantly,the air-dry density of Quercus ancient buried wood increased by 32.18%.Combined with the structure and chemical property of Quercus ancient buried wood,which shows that the cell structure of Quercus ancient buried wood have been squeezed,and there is a lot of sediment in cavity of wood cell and the cell walls,lead to thicker cell wall thickening,which is the main reason cause the increasing density,at the same time,higher content of wood extract and ash also led to it density increases.(2)The results show that the pyrolysis of Quercuswood is mainly divided into four stages: drying stage,pre-pyrolysis stage,pyrolysis stage and calcination stage.As the heating rate increases,the maximum weight loss rate and its corresponding temperature of the ancient buriedincrease significantly,and the TG and DTG curves move toward the high temperature side.The rate of temperature rise affects the pyrolysis process of the wood,and the higher the rate of temperature rise,the shorter the time required to reach the same degree of pyrolysis.With the increase of conversion rate α,the activation energy values of ancient buried and recent wood gradually increased.At the same conversion rate,the activation energy of Quercus ancient buried wood is higher than that of contrast wood,indicating that the thermal decomposition of Quercus ancient buried wood is more difficult than that of modern wood..It shows that under the same condition,thermal decomposition of Quercus ancient buried wood is more difficult.