Investigation on the system performance of waste heat recovery for boiler flue gas based on absorption heat pump

In order to improve the comprehensive utilization efficiency of waste heat boiler flue gas and reduce the boiler heat loss, the waste heat recovery system from boiler flue gas was designed based on the lithium bromide absorption heat pump. Furthermore, the performance and dynamic characteristics of the waste heat recovery system was analyzed with theoretical analysis method.The results showed that the system could exhibit high thermal efficiency and effectively save the amount of coal burning in addition to reduce the emission of CO₂. The annual saving of standard coal could reach 5.13×10⁵ kg while the annual reduction of CO₂ emission was amount to 4.04×10⁵ m³. The coefficient of performance(COP) would decrease slightly with the increase of evaporation temperature, but the change trend remained basically unchanged. The heat transfer rate was shown to increase with the temperature difference of circulating water. Besides, the recovery of standard coal was closely related to the temperature difference of circulating water, which was less affected by other factors. The system heat transfer rate was identified to have a positive linear relationship with the reduction of CO₂ emissions. The above conclusions would provide a theoretical reference for the analysis and calculation of the boiler waste heat recovery system.