Numerical Simulation on HCl Removal in Coal-Fired Flue Gas by Dechlorination Adsorbent Injection

Abstract

The injection of dechlorination adsorbents into the flue gas of coal-fired power plants is a reliable and effective method for mitigating the enrichment of Cl ions in wet flue gas desulfurization (WFGD) systems for the purpose of reducing desulfurization wastewater generation and discharge. However, the flue gas dechlorination efficiency varies depending on both the performance of the dechlorination adsorbent and the arrangement of the injection apparatus. This work focuses on the optimization of injection parameters for flue gas HCl removal of a 300-MW coal-fired power plant, utilizing a high-performance ethanol-hydrated CaO dechlorination adsorbent. A detailed evaluation of critical parameters, including injection velocity, injection height, and the Ca/Cl molar ratio, was conducted to elucidate their impacts on HCl removal efficiency. The results suggest that the Ca/Cl molar ratio is the most fundamental influencing factor. The injection velocity can alter the uniformity and spatial coverage of the dechlorination adsorbent. The injection height changes residence time, thus significantly affecting the dechlorination efficiency. The optimization strategy based on the CFD simulation provides a solid foundation and guidance for the industry application of the coal-fired flue gas HCl removal technology.