Experimental verification of the efficiency of selective non-catalytic reduction in a bubbling fluidized bed combustor

Kristýna Michaliková; Jan Hrdlička; Matěj Vodička; Pavel Skopec; Jitka Jeníková; Lukáš Pilař

doi:10.14311/AP.2022.62.0361

Authors

Kristýna Michaliková Czech Technical University in Prague, Faculty of Mechanical Engineering, Department of Energy Engineering, Technická 4, 166 07 Prague, Czech Republic
Jan Hrdlička Czech Technical University in Prague, Faculty of Mechanical Engineering, Department of Energy Engineering, Technická 4, 166 07 Prague, Czech Republic
Matěj Vodička Czech Technical University in Prague, Faculty of Mechanical Engineering, Department of Energy Engineering, Technická 4, 166 07 Prague, Czech Republic
Pavel Skopec Czech Technical University in Prague, Faculty of Mechanical Engineering, Department of Energy Engineering, Technická 4, 166 07 Prague, Czech Republic
Jitka Jeníková Czech Technical University in Prague, Faculty of Mechanical Engineering, Department of Energy Engineering, Technická 4, 166 07 Prague, Czech Republic
Lukáš Pilař Czech Technical University in Prague, Faculty of Mechanical Engineering, Department of Energy Engineering, Technická 4, 166 07 Prague, Czech Republic

DOI:

https://doi.org/10.14311/AP.2022.62.0361

Keywords:

selective non-catalytic reduction, SNCR, fluidized bed, BFB, denitrification

Abstract

Controlling nitrogen oxide (NO_X) emissions is still a challenge as increasingly stringent emission limits are introduced. Strict regulations will lead to the need to introduce secondary measures even for boilers with bubbling fluidized bed (BFB), which are generally characterized by low NO_X emissions. Selective non-catalytic reduction has lower investment costs compared to other secondary measures for NO_X reduction, but the temperatures for its efficient utilization are difficult to achieve in BFBs. This paper studies the possibility of an effective application of selective non-catalytic reduction (SNCR) of nitrogen oxides in a pilot-scale facility with a bubbling fluidized bed. The effect of temperatures between 880 and 950 °C in the reagent injection zone on NO_X reduction was investigated. For the selected temperature, the effect of the amount of injected reagent, urea solution with concentration 32.5%wt., was studied. The experiments were carried out using 500 kW_th pilot scale BFB unit combusting lignite. In addition, an experiment was performed with the combustion of wooden pellets. With reagent injection, all experiments led to the reduction of nitrogen oxides and the highest NO_X reduction of 58% was achieved.

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