Design And Experimental Study Of Heat Pump-Slime Drying System

In the field of coal mine,a lot of slime with high moisture and low calorific value will be produced in the process of coal washing.With the continuous increase of coal slime production,a large amount of coal slime accumulation causes environmental pollution.In order to accelerate the implementation of national environmental protection and energy conservation policy,the utilization of coal slime is an important task at present.In the process of slime treatment,slime drying is a very important link,reasonable and effective drying can not only reduce environmental pollution,but also improve the level of comprehensive utilization of coal.Compared with the traditional slime drying method,the heat pump drying technology has the advantages of energy saving and higher economic benefits.However,there are few studies on the combination of slime characteristics and heat pump drying technology,and there is a lack of theoretical and experimental research.Therefore,coal slurry heat pump drying technology research is very necessary.This thesis analyzes the current way of drying,solve the pollution and energy saving drying device,puts forward a kind of coal slime drying and heat pump drying technology with the combination of means.This is a method combining coal slurry drying with heat pump drying technology.Through theoretical research and experimental methods,the system is the design and optimization of the traditional closed heat pump drying system.The team set up an experimental platform air regenerator heat pump mucus drying system.First of all,the understanding of slime drying technology and heat pump drying technology at home and abroad.Secondly,through the theoretical analysis of the closed heat pump drying system process thermal calculation.Understanding the selection of heat pump working medium,the analysis of drying medium,the physical parameters of the material and the performance indicators of heat pump drying,a slime heat pump drying system of the overall configuration is proposed,by adding the air regenerator can cross heat exchange on the system,so as to improve the drying efficiency and energy utilization.Thirdly,the experimental research on slime heat pump drying system was carried out,and the slime heat pump drying experiment platform was built.The experimental material selection,experimental device design and selection,system design and installation,and experimental results were analyzed and discussed.(1)Through the experimental results of heat pump dry coating,the increase of air volume and the opening of electronic expansion valve will affect the increase of MER.The increase of air volume will affect the increase of SMER.With the increase of the opening of the electronic expansion valve,the peak change will occur.The heat of heat pump system increases obviously with the increase of wind volume.The influence of the opening of the electronic expansion valve is not obvious.The COP increased with the increase of the air volume and the electronic expansion valve opening.After comprehensive consideration,the fan frequency was adjusted to 50Hz,and the air volume was 2870m~3/h,the electronic expansion valve opening was 25%,and the MER maximum was 11.4kg/h.SMER is 0.95 kg/k Wh,COP is 5.23,the whole system drying time is short and energy saving,suitable for the field of dry clothes.(2)According to the results of heat pump slime drying experiment,it is found that the influence of air volume on the system changes obviously.The increase of air volume will lead to the increase of heat production,and the faster the drying chamber enters the preheating stage,The increase of air volume affects the peak change of COP.The opening of the electronic expansion valve has little effect on the heating capacity of the system.The influence of the electronic expansion valve on the inlet temperature,temperature and relative humidity of the inlet chamber is not obvious.The compression ratio decreases as the opening increases.COP also has a peak value change with the increase of electronic expansion valve opening.When the fan frequency is 46H and the electronic expansion valve opening is 19%,the COP will reach the maximum of 5.053.(3)Through the hot air drying experiment of blast dryer on slime,the drying effect of hot air experiment is not as good as that of heat pump drying in the same experimental time,and the water content of heat pump drying slime is 18.95%lower than that of hot air drying.This system is a closed system,no dust,no smoke,no pollution to the environment,no greenhouse gas emissions,the whole green pollution-free.The unit consumes a small amount of electric energy and the output is condensed water,which can avoid the secondary pollution of coal slime and is friendly to the environment.The actual operating COP of the system is 3.3～5.23,with obvious energy-saving effect.The system can improve the energy utilization and the comprehensive utilization of coal slime.