TY - JOUR TI - Study on heat transfer characteristics of flue gas condensation in narrow gap heat exchangers AU - Wang Yungang AU - Jiao Jian AU - Dai Yanjun AU - Ke Zhiwu AU - Zhao Qinxin AU - Li Feixiang JN - Thermal Science PY - 2023 VL - 27 IS - 6 SP - 4681 EP - 4693 PT - Article AB - Flue gas after wet desulfurization contains a large quantity of water vapor, as well as a small amount of fine particulate matter, acid and other pollutants. Direct emissions will cause haze and environmental pollution. Flue gas condenser can effectively recover latent heat of vaporization and remove these pollutants. However, the traditional flue gas condenser has disadvantages such as large volume, low heat exchange efficiency and easy blockage. To overcome these problems, a new type narrow gap heat exchanger, which is easy to detach and clean, is proposed. Then, the flue gas condensation characteristic is experimentally investigated. The factors including velocity and temperature of flue gas, flow and temperature of cooling water are studied on heat transfer coefficient and the condensation rate. The results indicate that the overall heat transfer coefficient is seven times of convection heat transfer coefficient, and the condensation rate can reach more than 60%. As the cooling water temperature increases, the condensation rate and condensation heat transfer coefficient gradually decrease. With the increasing of the flue gas velocity, condensation rate gradually decreases and condensation heat transfer coefficient gradually increases. Finally, the dimensionless correlation of Nusselt number is carried out, and the error is within 10%.