Search

Low-low temperature electrostatic precipitator technology is one of the important ways for energy saving and emission reduction of coal-fired power plants. In order to further improve the dust removal efficiency and enhance waste heat recovery performance, a novel H-type finned elliptical tube heat exchanger with longitudinal vortex generators is proposed. To achieve the maximum heat transfer enhancement with the minimum friction factor augmentation, the response surface model and multi-objective genetic algorithm are adopted to optimize the design parameters. Firstly, combined with the finite volume method and the central composite design method, the second-order response surface model between the design parameters (the length, height, angle, and position of longitudinal vortex generators) and the objective functions (Nusselt number and friction factor) is established. Then, based on the response surface model, the Pareto optimal solution set is obtained by the multi-objective genetic algorithm. Finally, by comprehensively comparing Nusselt number, friction factor and performance evaluation criteria of Pareto optimal solutions, the optimal combination is determined. Compared with the H-type finned tube heat exchanger, the performance evaluation criteria of the optimized novel heat exchanger is improved by 48–55%, which contributes to improve the overall performance of low-low temperature electrostatic precipitator system. The findings of this paper may provide practical guidelines for researchers and designers to develop efficient heat exchangers.

A latent heat thermal system suitable for high dusty flue gas environment is essential to regulate gas temperature fluctuation and improve dust removal efficiency. In the current study, an integrated thermal storage-transfer structure with phase change material (PCM) and honeycomb tube bundle was proposed and thermal response of a latent heat storage system was numerically studied. Firstly, the feasibility of using honeycomb tube bundle as thermal storage unit was verified. Next, the thermal performance enhancement of the PCM side was conducted by adding different internal fins. Finally, the predictive correlation of the suppression coefficient of temperature fluctuation was established to control the flue gas temperature reasonably based on the optimal fin arrangement obtained. The results of the present study show that the latent heat storage system with honeycomb tube bundle and internal fins is effective temperature control system. Among the five proposed internal fins, case 5 (with fins) has a higher melting and solidification rate than case 0 (without fin), and the complete melting and solidification time are reduced by 19% and 46%, respectively. According to the correlation of suppression coefficient, the latent heat storage system can be designed efficiently and reasonably, so as to improve the dust removal efficiency of the low-temperature electrostatic precipitation technology.