Coupling selective catalytic reduction process inside a coke oven regenerator: The influence of mixing parameters on NO reduction

Abstract

Many coking plants have adopted the process of preheating flue gas to apply medium and low-temperature SCR denitrification technology, which increases the NOx treatment cost, fuel consumption, and generates secondary pollutants. Based on the unique temperature distribution characteristics of the coke oven regenerator, this work proposes a method for synergizing SCR inside the regenerator to remove NOx. A three-dimensional numerical model of the synergy between heat storage and SCR reaction was constructed to study the influence of mixing parameters (atomization angle, injection velocity, nozzles number) on the NO reduction and NH3 distribution. The validity of the model was verified. The results showed that the uneven distribution of NH3 near the catalytic layer and the small SCR coating area limited the NO reduction efficiency. Increasing the number of nozzles was more beneficial than the injection velocity and atomization angle for improving the NH3 distribution uniformity and NO reduction efficiency, achieving a maximum NO reduction efficiency of 37.1% (reduced to 251.6 mg/m3). Further research found that the NO reduction capacity of the cooperative SCR model cannot exceed 36% without changing the thermal storage brick structure. When the inlet NO concentration is less than 235 mg/m3, the reaction model ensures that the outlet NO concentration meets the national emission standards.

Influence of Calcination Temperature over Vanadium–Molybdenum Catalysts for the Selective Catalytic Reduction of NOx with NH3

“…Unfortunately, the V 2 O 5 /TiO 2 catalyst exhibits high efficiency solely within a restricted temperature range of 300–420 °C, which limits its applicability in certain industrial processes. There are other kinds of flue gases in the nonelectric industry, such as coal coking ovens, where the temperature is below 300 °C since the SCR unit was equipped downstream of an air preheater . In this case, the conventional catalysts would not be feasible.…”