Heat transfer characteristics of a heat-recovery boiler built based on a modular mini boiler

• Published in: International Journal of Air-Conditioning and Refrigeration Vol. 32; no. 1; p. 9
• Main Author: Ahn, Joon
• Format: Journal Article
• Language: English
• Published: Singapore Springer Nature Singapore 29.04.2024; Springer Nature B.V; Springer; 대한설비공학회
• Subjects: Boilers; Cogeneration; Computational fluid dynamics; Energy; Engine exhaust gas; Engineering; Engineering Thermodynamics; Engines; Exhaust gases; Exhaust systems; Flue gas; Gas engine-based cogeneration system; Guide vanes; Heat and Mass Transfer; Heat exchangers; Heat recovery; Heat recovery systems; Heat transfer; Heat-recovery boiler; Modular mini boiler; Nonuniformity; Reynolds number; Risers; Temperature; Temperature distribution; Thermocouples; Thermodynamics; Water circulation; 기계공학; Heat-recovery boiler; Gas engine-based cogeneration system; Cogeneration; Engine exhaust gas; Heat transfer; Modular mini boiler
• ISSN: 2010-1333; 2010-1325; 2010-1333
• DOI: 10.1007/s44189-024-00053-z

The objective of this study is to design a heat-recovery boiler for a 1 MW-class gas engine-based cogeneration system intended to recover heat from engine exhaust gas. To accommodate high-pressure applications, a water tube-type boiler is selected. For ensuring effective water circulation within the boiler, an innovative modular-type boiler based on the mini-boiler concept is developed. This boiler comprises finned tube-type risers, and their heat-transfer characteristics are measured and compared with the conventional correlation used in the design process. Additionally, an inlet guide vane is developed to address the temperature nonuniformity resulting from the shape mismatch between the gas engine outlet and heat-recovery boiler inlet. The performance of the proposed boiler was evaluated by integrating it into an experimental rig. The diamond-shaped inlet guide vane, which was designed by computational fluid dynamics, facilitated a uniform temperature distribution. However, the temperature became nonuniform downstream owing to the influence of a downcomer. Although the modular heat-recovery boiler effectively produced steam from gas engine exhaust gasses, its heat-transfer performance in the downstream section was lower than expected, necessitating additional heat-transfer area.