| Wheat is one of the main food crops in China,with an annual output of more than 130million tons,occupying an important strategic position in food security and socio-economic development.Drying and storage are important links in wheat production and are also the key links most vulnerable to pollution.In particular,in case of continuous rainy weather,if it cannot be harvested and dried in time,it will lead to fungal pollution and mildew,which will seriously affect the yield and quality of wheat.Wheat drying technology can eliminate the drying link,and directly put it into storage after drying,so as to realize no landing production.It is an important means to reduce grain pollution.However,at present,the application of wheat harvesting and drying technology is less,and the wheat is harvested only when the moisture content of wheat is low,resulting in the loss of grain falling and 1000 grain weight;The storage equipment is backward,the function is single,and the loss of grain storage is serious.In view of the above problems,in order to reduce losses and ensure storage quality,this thesis designs an integrated drying and storage machine,combined with the timely harvest of wheat,which provides technical reference for the drying and storage of high moisture content wheat.The main research contents are as follows:(1)By measuring the 1000 grain weight and hardness of wheat from the wax ripening stage to the full ripening stage,analyzing the variation law of 1000 grain weight and hardness with time,and selecting the appropriate harvest time to reduce the loss of 1000grain weight of wheat,the results showed that the moisture content of wheat in the middle wax ripening stage was about 30%,the 1000 grain weight reached the maximum,but the hardness was about 5N,which was easy to crush and not suitable for harvest;At the end of wax ripening,the moisture content is 20-25%and the grain hardness is about 58n.Mechanical harvest can be carried out.At this time,the 1000 grain weight of dried grains is large;However,the moisture content at the completion stage is about 13%and the hardness is about 110N.Although it is suitable for mechanical harvest,the dry 1000 grain weight of grains is small.Through the 1000 grain weight and grain hardness,it was determined that June 5(the end of wax ripening)was the best period for wheat.The 1000grain weight was 1.16g greater than that of June 10(the completion of ripening period),and the yield increased by 274kg/hm~2,which had obvious yield increasing effect.(2)The integrated wheat drying and storage machine is optimized and designed.On the basis of the traditional grain storage steel plate warehouse,the hot blast stove is added,and the heating and ventilation pipe network at the bottom of the warehouse is optimized to realize the drying of wheat in the warehouse and improve the utilization rate of drying and storage equipment.A three-dimensional CFD theoretical model is established to simulate the drying process of wheat in the warehouse with high moisture content.It is determined that the optimal unit ventilation for warehouse drying is 70m~3/(h·T),the drying time is not less than 38h when the drying temperature is 55℃,and the mechanical ventilation time is not less than 133h.(3)An intelligent control system for drying and storage process is developed.The system reads the on-site status of elevator,spreader,level gauge,ventilator,warehouse exit auger,Warehouse Clearance auger and burner,displays the temperature and humidity inside the warehouse,outside the warehouse and at the air inlet in real time through the sensor,and feeds back the information through the logic control box of the actuator to realize two control logics of automatic ventilation and automatic drying in the automatic state;The button opening and closing of working parts can be realized under the manual control logic.(4)The drying storage experiment of high moisture content wheat was carried out in the drying and storage integrated machine,and compared with the traditional drying storage bag method.The grain storage effect and economic benefit were compared and analyzed.The results showed that the wheat intelligent drying and storage integrated machine can realize the safe storage of high moisture wheat,and the net loss rate is 6.74%,the quality loss rate is 2.98%compared with the traditional method;Compared with the traditional method,the storage cost is 61.87 yuan/T,and is not limited by the traditional drying site and weather conditions. |
