Numerical Simulation of the NO_x Emissions in a 1000 MW Tangentially Fired Pulverized-Coal Boiler: Influence of the Multi-group Arrangement of the Separated over Fire Air

Abstract

Computational fluid dynamics (CFD) investigations have been carried out to understand the combustion and NO x emission characteristics in a 1000 MW pulverized-coal boiler, which is equipped with a dual-circular tangential-firing system in a single furnace. One group of separated over fire air (SOFA) nozzles has been widely studied and used in controlling the NO x emissions in a pulverized-coal boiler. In this work, a multi-group of SOFA nozzle arrangement is investigated for the NO x control and reduction. The predicted results agree well with the measured information from the full-scale boiler. The flow field, temperature distribution, species concentration, and char burnout are discussed. The relationship between the NO x formation and the SOFA arrangement are analyzed. The numerical results show that the multi-group of SOFA nozzle arrangement is an efficient method to control the NO x emissions in the pulverized-coal boiler, with few unfavorable effects on the coal burnout. The arrangement of the two-group of SOFA nozzles being in service presents better ability than the one-group arrangement in reducing the NO x emissions. The distance between the two groups of the SOFA nozzles should be longer for a better result of NO x reduction. The technology of air-staging combustion presented in this work is good to enhance the understanding of the NO x formation characteristics and useful for the NO x control and reduction in pulverized-coal boilers.

Optimization of Air Distribution to Reduce NOx Emission and Unburned Carbon for the Retrofit of a 500 MWe Tangential-Firing Coal Boiler

“…Various studies of the optimization of SOFA to improve boiler performance have been reported in the literature based on experiments and/or computational fluid dynamics (CFD). Increasing the SOFA ratio and optimizing its detailed distribution were found to be effective in reducing NOx emission for various boiler types [6][7][8][9][10][11][12][13]. However, the change in reaction stoichiometry can also significantly alter the combustion and heat transfer characteristics.…”

Adsorption behavior of Pt embedded on N‐doped graphene sheets toward NO and NH3 molecules

“…In recent years, it can be seen that the NO x released from coal‐fired power stations is increasing gradually year by year . To effectively control NO x emissions, a series of technologies are applied to coal‐fired power plants for reducing NO x , including Low NO x Burners (LNB), Over Fire Air (OFA), Selective Non‐Catalytic Reduction (SNCR) and Selective Catalytic Reduction (SCR) . Among these technologies, SCR technology is the best developed technique for efficiently eliminating NO x emissions due to its efficiency and selectivity.…”

Numerical Analysis of Nox Production Under the Air Staged Combustion

“…This is not conducive to the formation of NOx, and makes the furnace exit NOx emissions reduction. Li et al (2015) and Zhou et al (2011) studied a 300MW coal-fired boiler and a 1000 MW tangentially fired pulverized-coal boiler of low NOx combustion retrofit, which increases the SOFA system, making air depth classification, can reduce the production of NOx. Li et al (2014) and Sun et al (2013) focused on the tangentially fired boiler with low nitrogen transformation and analyzed the furnace NOx emission characteristics.…”