Numerical Simulation And Optimization Analysis Of Process In WFGD Tower With Tangentially Spray Method

Realizing flue gas ultra clean emissions of coal-fired power plants is an inevitable trend in the survival and development of coal power industry. With our country intensifying the prevention and control of atmospheric pollutants, the current technology has been unable to meet the increasingly stringent SO₂ emission standards. Therefore, how to utilize the existing desulfurization device, guarantee the security and stability of the power system and save not only reform cost but operation energy consumption simultaneously, and even how to further improve the efficiency of flue gas desulfurization, become a hot topic in the study on today’s power plant environmental protection industry.This paper embarks from pre,in and post-combustion desulfurization and briefly summarizes several desulfurization technology methods which have currently used in the industrial production.This paper also details flue gas desulfurization limestone-gypsum wet flue gas desulfurization technology which is applied widely in coal-fired power plants, including basic principle,equipments,systems and the influence factors of desulfurization efficiency.Based on these,a desulfurization reaction method of adding desulfurizer swirling flow atomizing layer is proposed for spray towers and various parameters of a swirling flow atomizing layer are optimally analyzed.This paper uses Fluent simulation software as a platform to give a modeling analysis of a 100 MW unit wet flue gas desulfurization tower in a power plant.Based on two-film theory,we adopt Euler-Lagrange multiphase flow model and Simple algorithm to embed SO₂ absorption process in Fluent software by means of corresponding user-defined function module.In two cases of whether to add a swirling flow atomizing layer,3-d numerical simulation and analysis of gas flow field,flue gas temperature field and SO₂ concentration field are made.Meanwhile,in order to effectively leverage the flow field reconstruction function of a swirling flow atomizing layer,optimizing analysis of how relevant parameters effect the desulfurization efficiency is made in this paper from the angle and quantity of nozzles and the jet velocity of slurry in a swirling flow atomizing layer.The results prove that:（1）The flue gas flow field and temperature field directly affect the SO₂ concentration field in a desulfurization tower.（2）A swirling atomizing method not only can increase the process of flue gas and the gas-liquid surface area of contact in a desulfurization tower,but can effectively prevent the flue gas from escaping along tower walls and strengthen the mixing of gas-liquid two-phase in absorption zone.The desulfurization efficiency coincides with practical test results.（3） By selecting the diameter ratio d/D of a swirling flow atomizing layer as about 0.6 and setting at least eight nozzles,we are able to form a stable helical field,which is beneficial to improving the flow uniformity of flue gas. If we control the jet velocity of slurry in 15-20m/s,the desulfurization efficiency of a desulfurization spray tower will reach the highest.