Modelling of NOX Selective Catalytic Reduction in Pulverised Coal Power Plants

EDF has equipped its coal-fired power plants with nitrogen oxide emissions (NOx) reduction processes in order to ensure the regulatory pollutant emissions. A common control technique for limiting NOx emissions is the Selective Catalytic Reduction (SCR) of NOx by NH3 in presence of a catalyst. This process is the most developed and most widely used for flue gas treatment for the control of NOx emissions due to its efficiency, selectivity and economics. . Nevertheless, SCR management has to integrate some constraints such as deactivation by poisoning or ash-plugging that limits the lifetime of catalysts. EDF R&D has therefore developed an in-house SCR model describing, on one hand, the physicochemical processes occurring in the monolithic reactors and on the other hand, the catalyst deactivation due to poisoning. This modeling is used as a basis for optimizing the control and maintenance of SCR processes in EDF’s coal-fired power plants. This paper provides results of NOx emission and ammonia slip which are compared to power plant measurements.