【摘 要】
：
High-level Nitrogen oxides(NOx)released to the atmosphere cause health and environmental hazards.Conventional power plants are required to have NOx emission control systems to abide by local environme
【机 构】
：
Spray Analysis and Research Services,Spraying Systems Co.,USA
【出 处】
：
13th International Conference on Liquid Atomization and Spra
论文部分内容阅读
High-level Nitrogen oxides(NOx)released to the atmosphere cause health and environmental hazards.Conventional power plants are required to have NOx emission control systems to abide by local environmental regulations.Common post-combustion techniques include selective non-catalytic reduction(SNCR)or selective catalytic reduction(SCR)techniques.SNCR is a proven technology that can be implemented virtually without affecting existing industrial operations with low capital cost.SNCR is a method involving either aqueous ammonia or urea as the reagent injected into flue gas in the boiler/furnace within specific temperature range.This method commonly reduces the emission of NOx by 30-50%.However,high reductions can be achieved by system optimization.Placement within the proper temperature window,distribution within the cross section and residence time of reagent significantly influence performance of an SNCR system.Therefore,spray lance and nozzle design is crucial for assurance of operating efficiency and ammonia utilization.In this paper,an SNCR system in a circulating fluidized bed(CFB)boiler was studied with using Computational Fluid Dynamics(CFD)simulations,as it relates to spray technology.The simulation solves Navier-Stokes equations with heat and mass transfer using ANSYS Fluent SNCR model with Lagrangian multiphase models and species transport model.CFD was used to diagnose the gas phase behavior and thermal distribution,to determine optimal spray placement and maximum penetration.The focus of this work was the injection parameters,which were determined based on test data acquired through in-house laboratory equipment.Temperature profile,pollutant reduction,ammonia slippage and wall impingement were used from the CFD results to assist determining the best spray design to achieve the greatest efficiency.
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