Development Of New And Efficient Heat Pump Grain Dryer And It's Performance Study

Cereal drying is an important link before storage and one of the important means to ensure grain security.A reasonable drying method not only ensures the dry quality of the grain,increases its additional value,but also prolongs the shelf life of the cereal.Grain drying is a high-energy industry.The traditional drying method is to dry by burning coal.Under the energy development trend of energy-saving and environmentally-friendly,in order to reduce drying energy consumption and reduce pollutant emissions,it is of great significance and broad prospect in engineering fields to develop high-efficiency and energy-saving new technologies for grain drying.To this end,this paper designed a new type of high efficiency heat pump grain drying system,and developed a continuous grain vacuum dryer used with the system.The heat pump technology is used in new and efficient heat pump grain drying system to recover the latent heat of steam generated during vacuum drying of the grain,and provides a heat source for the continuous grain vacuum dryer.The method not only can take advantage of vacuum drying technology and heat pump technology,but achieve efficient and energy-saving drying through waste heat utilization while ensuring the quality of grain drying.The continuous grain vacuum dryer developed in this paper mainly comprises an inner cylinder,an outer tube,a feeding device,a discharging device,a transmission device,a vacuum tube and a bracket.The structure of the whole machine is drum type,which is stable in operation and good in sealing performance.Experimental studies on corn have shown that the dryer can achieve continuous vacuum drying of the grain.Under the conditions of inner cylinder rotation speed 1.5 r/min,drying temperature 80 ?,drying pressure 9 k Pa or inner cylinder rotation speed 2.0 r/min,drying temperature 85 ? and drying pressure9 k Pa,corn with higher drying quality can be obtained.The new and efficient heat pump grain drying system in this paper is an absorption heat pump grain drying system.The thermodynamic calculation and analysis of the system show that the drying system has good performance and high overall energy utilization,with a COP of 2.04 and a SMER value of 1.16 kg/(k W· h).Compared with the general grain dryer,the drying energy consumption can be reduced by about 40%,and the sulfur dioxide,nitrogen oxides and carbon dioxide emissions are greatly reduced,which has great energy saving benefits and environmental benefits.