Coupling Electrochemical NO Reduction with Selective Catalytic Reduction for Off-Gas Treatment Without External Reducing Agents

Industrial & Engineering Chemistry Research, vol. 65, pp. 6103–6114

Abstract

The removal of nitrogen oxides (NO x ), specifically NO and NO 2, is crucial in the treatment of industrial off-gases. It is typically done using reducing agents like ammonia through selective noncatalytic or selective catalytic reduction (SCR). A promising alternative independent of external reducing agents is electrochemical nitrogen oxide reduction (NORR) to NH 3, but challenges arise at lower NO concentrations typical of industrial off-gases, affecting Faradaic efficiency. We propose a novel process that combines NORR and SCR: half of the NO x is converted to NH 3 via NORR, and the remaining NO x is reduced via SCR using the NH 3 produced before. This approach overcomes NORR limitations, reduces NORR electricity consumption by approximately 50%, and eliminates SCR’s need for external NH 3 . Our techno-economic analysis indicates that this NORR-SCR configuration has slightly higher costs than traditional SCR, while offering the potential for lower costs through optimized catalyst performance and enhanced sustainability via electrification and renewable energy integration.

Authors 6

1. Michael J. Rix Aachen Process Systems Engineering (AVT.SVT)

   RWTH Aachen University

   Affiliation as printed

   Process Systems Engineering (AVT.SVT), RWTH Aachen University, Forckenbeckstraße 51, 52074 Aachen, Germany

2. Wenzel Plischka Aachen Chemical Process Engineering

   RWTH Aachen University

   Affiliation as printed

   Chemical Process Engineering (AVT.CVT), RWTH Aachen University, Forckenbeckstraße 51, 52074 Aachen, Germany

3. Adrian Martens Aachen Process Systems Engineering (AVT.SVT)

   RWTH Aachen University

   Affiliation as printed

   Process Systems Engineering (AVT.SVT), RWTH Aachen University, Forckenbeckstraße 51, 52074 Aachen, Germany

4. Matthias Wessling Aachen Chemical Process Engineering DWI Interactive Materials Research

   DWI – Leibniz Institute for Interactive Materials · RWTH Aachen University

   Affiliation as printed

   Chemical Process Engineering (AVT.CVT), RWTH Aachen University, Forckenbeckstraße 51, 52074 Aachen, Germany

   DWI Interactive Materials Research, Forckenbeckstraße 50, Aachen 52074, NRW, Germany

5. Robert Keller Aachen Chemical Process Engineering

   RWTH Aachen University

   Affiliation as printed

   Chemical Process Engineering (AVT.CVT), RWTH Aachen University, Forckenbeckstraße 51, 52074 Aachen, Germany

6. Alexander Mitsos corresponding Aachen Process Systems Engineering (AVT.SVT)

   Forschungszentrum Jülich · Jülich Aachen Research Alliance · RWTH Aachen University

   Affiliation as printed

   Energy Systems Engineering (ICE-1), Forschungszentrum Jülich

   JARA-ENERGY

   Process Systems Engineering (AVT.SVT), RWTH Aachen University, Forckenbeckstraße 51, 52074 Aachen, Germany