Combining HC-SCR over Ag/Al2O3 and hydrogen generation over Rh/CeO2-ZrO2 using biofuels: an integrated system approach for real applications

Journal article, 2015

We report on a high NOxreduction activity over Ag/Al2O3catalysts, using hydrogen produced in a fuelreformer. The focus of the study is to evaluate the performance of a hydrocarbon selective catalyticreduction (HC-SCR) catalyst in real conditions. Initially, the catalytic materials for the fuel reformer(Rh/CeO2-ZrO2) and the HC-SCR (Ag/Al2O3) were evaluated in separate bench-scale reactor setups. Thesetwo setups were subsequently joined into an integrated bench-scale reactor setup with the aim to evalu-ate the influence of the reformate on the HC-SCR activity in a controlled environment. In the final phase ofthe study a 4 wt.% Ag/Al2O3catalyst doped with 100 ppm(w) Pt was scaled up and tested in a pilot-scalereactor setup. The pilot-scale reactor setup enabled evaluation of the HC-SCR activity in real exhaustgases generated by a single cylinder engine (genset) together with a hydrogen-rich gas supplied froma fuel reformer. Commercial biodiesel (NExBTL) was used as reducing agent for the HC-SCR as well asfuel in the fuel reformer for both the bench-scale and pilot-scale experiments. This study gives an excel-lent link between evaluations of the catalytic materials, controlled bench-scale experiments and appliedengine experiments, proving a viable concept for lean NOxreduction together with onboard hydrogenproduction. A NOxconversion of above 70% was reached at temperatures below 250◦C, in bench-scaleexperiments when hydrogen produced in the fuel reformer is added.