CLEERS Teleconference: Prof. Olaf Deutschmann, Karlsruhe Institute of Technology

Challenges in emission control of natural gas and hydrogen engines

Prof. Olaf Deutschmann
Karlsruhe Institute of Technology

Abstract:

Lean-operated internal combustion engines fueled by natural gas (NG) or hydrogen have attracted a lot of interest recently due to their potential to reduce or avoid emissions of greenhouse gases. Since the fuel is burnt by air both types of engines produce significant amounts of nitrogen oxides raising the need for an efficient after-treatment system if ultra-low emission limits are to be met. In NG engines, slip of the fuel methane and the realase of its combustion intermediate formaldehyde pose additional challenges. In combination with ammonia, the presence of formaldehyde in the exhaust can lead to the catalytic formation of toxic HCN over typical NH3-SCR catalysts [1]. Gas phase reactions in the tailpipe close to the NG engine may lead to an additional formation of formaldehyde [2], and change the NH3/NOx ratio [3] impacting the performance of the emission control system.

The seminar will discuss recent results of the Exhaust-Gas Center Karlsruhe on oxidation catalysts and regeneration strategies to reduce the emissions of methane [4] and formaldehyde [5] from lean-operated NG engines, NH3-SCR for NOx removal including deposit formation from urea-water-solutions [6], and the potential of H2-SCR for NOx removal of the exhaust of H2-engines [7].

[1] D. Zengel, P. Koch, B. Torkashvand, J.-D. Grunwaldt, M. Casapu, O. Deutschmann. Angew. Chem. Int. Ed. 59 (2020) 14423.
[2] B. Torkashvand, P. Lott, D. Zengel, L. Maier, J.-D. Grunwaldt, O. Deutschmann. Chem. Eng. J. 377 (2019) 119800.
[3] S. Schmitt, S. Schwarz, L. Ruwe, J. Horstmann, F. Sabath, L. Maier, O. Deutschmann, K. Kohse-Höinghaus. Intl. J. Chemical Kinetics 53 (2020) 213.
[4] K.A. Karinshak, P. Lott, M.P. Harold, O. Deutschmann. ChemCatChem 12 (2020) 3712.
[5] B. Torkashvand, L. Maier, T. Schedlbauer, M. Casapu, J.-D. Grunwaldt, O. Deutschmann. Chem. Eng. Sci. 195 (2019) 84.
[6] M. Börnhorst, S. Langheck, H. Weickenmeier, C. Dem, R. Suntz, O. Deutschmann. Chem. Eng. J. 377 (2019) 119855.
[7] M. Borchers, K. Keller, P. Lott, O. Deutschmann. Ind. & Eng. Chem. Res. 60 (2021) 6613