Energy Efficient Research On Waster Recovery Device In Wood Drying Exhaust

Wood drying is the most volume energy consumption process in wood producing, it is about40～70percentage in the total.15-40percentage of them are taken off by eliminating the exhausted moist and heat drying medium. So it is very important to recover the waste heat.This paper first designed the shell-and-tube heat exchanger, researched the exhaust heat recovery of the conventional wood kiln, based on the theoretical analysis and forced centralize air-exchange, designed a exhaust heat recovery device, which was used wood drying kiln with forced centralize air-exchange. This device is consisted of a heat exchanger, direction valve; two sets of hot moisture ducts and exhaust fan, two sets of inlet ducts of inhaul refresh air and inlet fans. Testing and analyzing its effect on the save energy, combine the basic technical performance and efficiency, it can provide the fundamental basis for promotion and application in production.(1) By testing the different drying stages, through exhaust heat recovery device the fresh air’s temperature can increase9～11.9℃and the moisture air’s can lower13～16.3℃。(2) The heat recovery effect of the early and medium-term is more significant than late-term It is recovery wasted heat rate is8.2%to28%, the average rate is22%.(3)A volume of80m3lumber drying kiln can recovery energy is about2.30×107kJ which is equal to standard coal786.06kg, which heat value is29260kJ/kg. We can save about8646.60kg standard coal if a drying kiln dries11times per year. The price of the fan is2,500yuan and this device costs1,6200yuan, heat recovered fees are10010.2yuan (the price of the standard coal is1157.7yuan/ton), the cost recovery is37.8months.