Experimental and Numerical Simulation of the Resistance Characteristics and Desulfurization Efficiency of Rod-Shaped Turbulators in WFGD for Green Power Systems

The Wet Flue Gas Desulfurization (WFGD) process has always been an important part in the low-carbon/green power realization process of traditional power plants. Adding a turbulator to the spray scrubber can improve the desulfurization efficiency, whereas it also increases the flow resistance. In this study, a small experiment device based on a spray scrubber with a turbulator in a power plant was built on a 1:10 scale to address the problem. The influence of the flue gas flow rate and the liquid–gas ratio on the flow resistance was investigated. A mathematical model was established for the two-phase flow and the SO2 liquid phase absorption reaction, and numerical simulations were achieved by the Fluent code. The resistance characteristics and the liquid droplet residence time were studied in detail. By fitting the experimental data, the relationship between the resistance coefficient, the Reynolds number, and the liquid–gas ratio in the tower was determined as the following: f = 0.0288 Re0.359(L/G)0.754. The desulfurization efficiency was calculated by adopting a user-defined function (UDF) code in a computational fluid dynamics (CFD) model, and the effects of the flue gas flow rate, temperature, and the liquid–gas ratio were analyzed. The results show that the effect of the rod-shaped turbulator on the flow resistance is much less than the effect of the liquid spray. The residence time of droplets around the turbulator is doubled. The pressure loss in the scrubber increases with the liquid–gas ratio (associated with the number of spray layer) and the flue gas flow rate. The turbulator can improve the uniformity of the flue gas velocity to some extent and increase the utilization rate of the spraying liquid, thereby increasing the desulfurization efficiency by 2.49%. Considering the operation cost, the reasonable value range of the liquid–gas ratio is 20~30. This work presents a good demonstration of combining the experiment and numerical simulations on a laboratory scale for large systems and associated components research, which is helpful for the engineering design and optimization of modern green power systems.