Research And Experiment On Key Technologies And Equipment Of Grain Multi-field Collaborative Drying

Grain is the foundation of people's livelihood.It relates to the security and stability of the country.As a key step in grain harvest process,drying technology and equipment play an important role to ensure grain's quality and safety.In recent years,under the guidance of policy,the number of grain dryers has developed rapidly from around 1500 overall market increment in 2010 to about 22 thousand in 2017,but the present grain drying mechanization degree is only 18.2%.In the last 80 years,developed countries' mechanized drying has achieved automatic operation as a level of 90%,and the level of integrated mechanization in China over 70%.Consequently,the development of drying mechanization is imbalanced,and the postpartum loss of grain is still very serious.There are many reasons for the problem.The design of the drying system and its effectiveness evaluation can't reflect the effect of the energy consumption objectively.The drying process equipment has design defects.The lack of research and application of multi field cooperative drying is one of the essential reasons.In this study,according to the idea of "technical problems of industrial equipment,the theoretical foundation of drying design,key technology research,multi field coordination key technology equipment design and test",a systematic research work has been carried out around high quality,high efficiency,energy saving and dry drying mechanized drying targets.The research work and innovation of the paper are mainly reflected in the following aspects:1.The present development of drying equipment is analyzed.The key technology,the technology theory,the evaluation method,as well as the problems caused by the technology model in the grain drying technology and equipment are clarified.The design and efficiency evaluation of the grain drying system are pointed out,and the effect of the objective drying system can't be ignored.The development of multi field collaborative drying process equipment is the main way to achieve high quality,high efficiency,energy saving grain drying.2.The change law of the grain moisture binding energy and the state parameters of the grain drying system was analyzed.Based on the analysis of the drying system,a high humidity grain safe storage drying process system was established,and the energy saving dryer was designed accordingly.From the theory and experiment,the utilization effect of the energy and potential energy of the drying system was confirmed,and the high humidity grain was illustrated.In the storage dryer,The test results of temperature and water content change process show that the temperature of the grain can be reduced to below the ambient temperature of 10?,and the precipitation rate is above 0.76%d.b./h.The research results show the efficient and energy-saving method for the design of grain drying process system,and provide a high efficiency and energy-saving pre drying equipment for the large grain centralized drying facilities.3.An infrared thermal radiation dryer was designed.According to the design concept of far infrared,quality improvement,speed increase,heat transfer enhancement,air diversion,depressurization,vaporization,grain cooling and quality protection,the control strategy of low temperature drying was determined by using the model of grain drying temperature and flow speed,and the design and experiment of a multi field cooperative dryer for grain were completed,and the experimental results showed that In the range of temperature change from 69.7 to 78.3?,the maximum grain temperature is 35 degrees,which is 9 to 11 degrees centigrade compared with the traditional dryness drying method,and it is more than 30% higher than the traditional air blast.