Study On The Performance Of Compressed Air Drying System With An Ejector Cooler Driven By Waste Heat

In order to alleviate the environmental problems caused by global warming,China put forward the goals of "peak carbon dioxide emissions" and " carbon neutrality" at the75 th United Nations General Assembly.Energy conservation and emission reduction are one of the ways to achieve these goals.China is a large industrial country,and the production and drying of compressed air is an important part of industrial energy consumption.In view of the high cost of compressed air freeze-drying and the large waste heat of air compressors,this paper proposes a compressed air drying system with an ejector cooler driven by waste heat.The biggest feature of this system is that the waste heat of air compressor is used as the heat source to drive the ejector cooler.The system uses the cooling capacity produced by the ejector cooler to freeze-dry the compressed air.Based on the establishment of theoretical models of various components,this paper conducts a system simulation to study the influence of generation temperature,condensation temperature,and evaporation temperature on system performance.Finally,guided by theoretical research,an experimental device was built to verify the influence of the evaporation temperature and the generation temperature on the system performance.Through theoretical simulation and experimental research in this paper,the following conclusions are obtained:(1)Under certain working conditions,the cooling capacity of the ejector cooler can meet the drying demand of the compressed air,which proves that the system has good feasibility.(2)Theoretical simulation results show that the air pressure dew point at the outlet of the system decreases with the increase of the generation temperature,increases with the increase of the condensation temperature,first decreases and then increases with the increase of the evaporation temperature,that is,there is an optimal evaporation temperature.(3)The experimental research results show that the air pressure dew point at the outlet of the system first decreases and then increases with the increase of the evaporation temperature,and decreases with the increase of the generation temperature.The trend is consistent with the theoretical results.(4)Compared with the compressed air drying equipment driven by traditional electric cooler,this system has higher performance coefficient and lower operating cost.However,due to the insufficient heat exchange capacity of the evaporator and the high degree of supercooling of the condenser in the experiment,the performance of the system still has a certain room for improvement,so it has the value of further research.