Numerical Simulation On SCR Flue Gas DeNOx System For 660MW Power Plant Boiler

With the rapid development of Chinese power industry, the emissions of nitrogen oxides increased, and the government requires much strictly on environment, the power plans are asked for reducing the emissions of nitrogen oxides. Selective Catalytic Reduction(SCR) flue gas denitrification technology becomes the most widely used DeNOx technology with the advantage of high efficiency and reliable operation. This article bases on the related heat and mass transfer theory of SCR system, establishes a model of a 660MW unit SCR system with Gambit, uses Fluent to Simulate heat and mass transfer and chemical reaction within the SCR system. Calculates the flow and heat transfer conditions of SCR system of the presence or absence of baffles. By installing baffles of proper structure and number can largely improve the velocity field in SCR system, makes it evenly distributed and inhibits the reflux of the entrance. The increase of the distribution of uniformity and the reducing of velocity gradient in the catalytic layer can take advantage of the catalyst and improve the efficiency of catalytic. Use the linear controlled ammonia injection grid to divide the nozzle into two groups internally and externally, and adjust the amount of ammonia spray with NH3/NOX molar ratio to make NH3 and NOX well mixed. By simulating the whole SCR system can conclude that by installing suitable deflector and adjusting the ammonia injection grid can make the SCR system meet design requirements, reduce the content of NO and make the pressure drop and ammonia escape rate within the control range. The optimized result of stimulation was applied to a power plant. Through performance test the SCR system performance indicators meet the design requirements and the stimulation results accuracy was verified.