Enhancement of Mass Transfer between Flue Gas and Slurry in the Wet Flue Gas Desulfurization Spray Tower

摘要

This paper presents an enhancement method to improve the desulfurization performance of wet flue gas desulfurization (WFGD) by adding a flow pattern controlling (FPC) device in the spraying tower. The FPC device is characterized by a modular design and composed of FPC units that are fixed under the spraying layers of the desulfurization tower. Two kinds of FPC units, each with a different scale, are designed (i.e., unit A and unit B). The effects of the FPC unit and operational parameters on the desulfurization process are determined by experimentation. The experiments show that the FPC unit significantly improves the desulfurization performance compared to the common spraying column without an aperture plate. The flow regime significantly changes and large amounts of bubbles develop above the perforated plate in the FPC unit, which is beneficial to enhance gas liquid mass transfer. The design style and structural parameters of the FPC unit both significantly influence the desulfurization performance. According to the results, optimal desulfurization performance is achieved with four holes and an aperture ratio of 0.65 for unit B. For L/G = 10 L/m(3), the desulfurization efficiency of unit B reaches 77% (approximately 22% increase) with a pressure increase of 370 Pa. The relationship between the operational parameters and the different scale units is investigated under different test conditions. In addition, the results show that the range of improvement with the perforated plate is related to the gas liquid flow regime in the unit. Finally, we attempt to build an empirical correlation formula of each influence factor on desulfurization efficiency and pressure drop based on the experimental results.