Utilizing waste heat in gas boilers industry
Jin, Junhao (2025)
Kandidaatintyö
2025
School of Energy Systems, Energiatekniikka
Kaikki oikeudet pidätetään.
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi-fe2025073080175
https://urn.fi/URN:NBN:fi-fe2025073080175
Tiivistelmä
As energy transition and emission reduction pressures rise, improving energy efficiency in gas-fired industrial boilers has become critical. Although gas boilers have the advantages of clean combustion, fast response, and precise control, they cause significant energy losses due to the direct emission of high-temperature flue gas.
This study reviews mainstream waste heat recovery technologies, including conventional heat exchangers, Organic Rankine Cycle (ORC) systems, and heat pumps. Each has limitations: exchangers offer shallow recovery, ORC systems are costly and efficiency-limited, and heat pumps depend on electricity and have fluctuating economics.
To overcome these issues, this thesis proposes a novel approach inspired by electric arc furnace waste heat recovery systems. It introduces a compact, integrated recovery module—featuring multi-stage heat exchange, thermal storage, and regulation—applied to the tail section of gas-fired boilers.
Simulation results show that while traditional methods improve thermal efficiency by up to 2%, the proposed system achieves 2–3% gains without relying on electricity, offering enhanced stability and control. A modular integration strategy is also proposed for small- and medium-scale boilers.
This solution demonstrates strong engineering practicality and provides a solid foundation for future research on multi-level heat utilization, low-carbon boiler design, and thermoelectric system optimization.
This study reviews mainstream waste heat recovery technologies, including conventional heat exchangers, Organic Rankine Cycle (ORC) systems, and heat pumps. Each has limitations: exchangers offer shallow recovery, ORC systems are costly and efficiency-limited, and heat pumps depend on electricity and have fluctuating economics.
To overcome these issues, this thesis proposes a novel approach inspired by electric arc furnace waste heat recovery systems. It introduces a compact, integrated recovery module—featuring multi-stage heat exchange, thermal storage, and regulation—applied to the tail section of gas-fired boilers.
Simulation results show that while traditional methods improve thermal efficiency by up to 2%, the proposed system achieves 2–3% gains without relying on electricity, offering enhanced stability and control. A modular integration strategy is also proposed for small- and medium-scale boilers.
This solution demonstrates strong engineering practicality and provides a solid foundation for future research on multi-level heat utilization, low-carbon boiler design, and thermoelectric system optimization.