Research and Application of Waste Heat Recovery and Cascade Utilization for Low-grade Flue Gas in Industrial Field

To satisfy the actual demands of industrial enterprises, a comprehensive and high-efficient system based on the principle of thermodynamics, and applicable to recovery and cascade utilization of waste heat for low-grade flue gas in industrial field, has been researched and developed within modern sensor technology, automatic measurement and control technology, and high-efficient heat exchange technology. It has been applied to practical production in the industrial enterprise. Modular design has been adopted, which can better adapt to the highly-variable working conditions during the productive process and then achieve automatic dynamic control for the amount of recovery and utilization. It has gotten rid of the low efficiency of recovery and utilization for low-grade waste heat below 250 °C in the industrial enterprises. Moreover, it overcame the defects of analogous system, such as narrow range of application, low efficiency of recovery and utilization, poor level of automation, and complexity and poor precision for operation. The practical application in the industrial enterprise has demonstrated that the system can only save the energy cost beyond 300,000 ¥/a, but also decrease energy waste and thermal pollution caused by direct emission of waste heat. Therefore benefit society and economy were significantly.