Preparation And Application Of Balsa Wood Powder/Polyglycol Composite Phase Change Heat Storage Material

Wood drying is the most energy-consuming link in the production process of wood products,and the heat loss of the wood drying chamber shell is as high as 20%-30% of the total energy consumption of the drying.To solve the heat loss of the wood drying chamber shell,improve the utilization rate of heat energy.This study proposes a new idea to reduce the heat loss of the wood drying chamber shell by using composite phase change heat storage.Polyethylene glycol is selected as the phase change heat storage material.Polyethylene glycol has the advantages of high energy storage density,small thermal conductivity,and wide sources.However,leakage is likely to occur during the phase change process.This paper selects(modified)Balsa wood As the encapsulation matrix of polyethylene glycol,the powder is prepared(modified)by Balsa wood powder / polyethylene glycol composite phase change heat storage and insulation materials by normal temperature impregnation and vacuum evaporation.The influence of the performance of the composite phase change heat storage material;theoretical calculation of the application of the composite phase change heat storage material provides a theoretical basis for the practical application of the composite material.The main conclusions are as follows:(1)Balsa wood powder has poor encapsulation ability for polyethylene glycol,the mass fraction of polyethylene glycol in the composite phase change heat storage material is only 59.72%,the composite phase change heat storage material has good encapsulation effect,and thermal cycle High stability,the phase transition temperature of melting and solidification are 53.55 ? and 39.4 ?,latent heat of melting and solidification are 112.6 k J / kg and 95.60 k J / kg,respectively,and the thermal conductivity is 0.2788 W /(m K).(2)After delignification modification of Balsa wood powder,lignin is completely removed,which improves the pore size distribution and specific surface area of Balsa wood powder,and releases some active hydroxyl groups,making modified Balsa wood powder / polymer The mass fraction of polyethylene glycol in the ethylene glycol composite phase change heat storage material is increased to 75.12%,the phase transition temperatures of melting and solidification are 53.34 ?,41.15 ?,latent heat of melting and solidification are 137.8k J / kg,124.9 k J / kg,respectively,thermal conductivity 0.270 W /(m K).(3)Through theoretical calculation of the shell heat loss in the drying process of coniferous and broad-leaved wood in different structure drying rooms,the application of the prepared composite phase change heat storage material can greatly improve the insulation performance of the drying room.Red spruce is dried in a drying room equipped with a composite phase change heat storage material,which can reduce the heat loss by 24.24% and 31.7% on the basis of the ordinary drying room respectively,and has a significant thermal insulation effect.It has a relatively high reference value for energy-saving drying with wood.