Development of integrated technology for waste heat recovery from humid flue gas of hot water boiler

• Published in: International journal of energy research Vol. 45; no. 13; pp. 19560 - 19573
• Main Authors: Cui, Zhaoyang, Du, Qian, Gao, Jianmin
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Inc 25.10.2021; Hindawi Limited
• Subjects: Absorption; Air pollution; Boilers; Carbon dioxide; Coal; Design; Design parameters; Emissions control; Energy; energy and water recovery; Energy conservation; energy conversion; Feasibility studies; Flue gas; Heat; Heat exchangers; Heat pumps; Heat recovery; Heat recovery systems; Hot water; humid flue gas; Load distribution; Pollutants; Pollution control; Power consumption; Recovery; Resource consumption; Steam turbines; Subsystems; thermodynamic analysis; Towers; Turbine engines; Turbines; Waste heat; Waste heat recovery
• ISSN: 0363-907X; 1099-114X
• DOI: 10.1002/er.7057

Summary For coal‐fired hot water boilers, we developed a comprehensive waste heat recovery system coupled with a packed tower, industrial steam turbine, and absorption heat pump, which can directly reduce the auxiliary power consumption, realize energy cascade utilization, and waste heat recovery. The ASPEN Plus software was used to simulate the packed tower, absorption heat pump, and industrial steam turbine system. The design parameters of the system were obtained and the operation characteristics of the system under load rates of 25%, 50%, 75%, and 100% were investigated, the feasibility of steam subsystem transformation was also analyzed. Taking a 140 MW coal‐fired boiler as an example, in the range of 25%~100% load rate, the direct energy saving can reach 118 to 523 kW∙h, the waste heat recovery power is 2.7 to 11.4 MW, and the coal saving can reach 374 to 1605 kg/h, resulting in energy and resource consumption reduction effect, the system also has CO2 and pollutant emission reduction effect. The RadFrac model can be used in packed tower design, the system can work well under variable load conditions. Based on humid flue gas energy and water recovery technology using packed tower as the heat exchanger, we developed a waste heat recovery technology coupled with industrial steam turbine, packed tower and absorption heat pump, which can directly reduce the auxiliary power consumption and realize energy cascade utilization and waste heat recovery.