The Application Research Of Oil-free Screw Air Compressor Waste Heat Recovery System In Textile Mill

In the paper, the background of air compressor waste heat recovery was firstly introduced, and pointed out that in textile mill, the compressed air system is one of the essential power sources to the process of production, its energy consumption accounts for about 10%~35% of the total energy consumption of textile mill, but a lot of energy is discharge into the environment in the form of heat, resulting in the heat waste and environment heat pollution. Therefore, how to recycle and take advantage of the waste heat will have important energy conservation implications for textile mills. Secondly, the study situation of air compressor waste heat recovery at home and abroad was also described, pointing out the shortcomings in the oil-free screw air compressor waste heat recovery aspects, and proposed to explore the oil-free screw air compressor waste heat recovery.In addition, the compression thermodynamic processes of air compressor were briefly analyzed, theoretically pointing out the feasibility of waste heat recovery. Several ways of air compressor waste heat recovery were also summarized, choosing the way that the oil-free screw air compressor could use: A secondary heat exchanger system was set in the outside on the basis of the internal heat exchanger in air compressor itself. By setting the secondary heat exchange system to extract the heat from the air compressor, and supply the plant with hot water, so as to achieve the targets of waste heat and energy conservation.On the basis of the secondary heat exchange system, the characteristics of plate heat exchanger and shell and tube heat exchanger were introduced according to the different water quality in the end water point, and made a simple comparison between the former and the latter. After then, a calculation of waste heat recovery equipment selection was made, such as the plate heat exchanger for the heating system and the shell and tube heat exchanger for the sanitary hot water system.Then a discuss about the change of compressed air’s temperature which has an effect on the quantity of the heat exchanger in air compressor was made, drawing that: the total heat recoverability rate of air compressor varied with the temperature difference of compressed air before and after compression, while it has no direct relationship with the inlet temperature of compressed air. By testing the water temperature in the second heat exchanger, calculating the actual recovery efficiency of heat transfer in the second heat exchanger side was around 55%, and the heat transfer imbalance rate was in the range of 2%~9%. And the energy efficiency which reflected the enthalpy difference of the compressed air, as for the air compressor selected in the paper, the enthalpy of the output compressed air accounted for about 6% to 7% of the input power by calculating.Finally, the application of oil-free screw air compressor heat recovery-cooling system in a textile in Xi’an was described, and the energy conservation effect and economy were analyzed too. Through calculation, it could be demonstrated that the quantity of heat recovery of all air compressors can meet the thermal load of the mill. With heat recovery systems, not only about 1.37 million yuan of resource and energy costs can be reduced for the enterprise every year, but also can reduce CO2 emissions 4306 t and SO2 emissions 39.8t per year, which is positive to reduce the environmental pollution.