Effects of critical structure parameters on conversion performance enhancement of a Pd-Rh dual-carrier catalytic converter for heavy-duty natural gas engines

In this work, the effects of structure parameters on the conversion performance of the dual-carrier catalytic converter for heavy-duty natural gas engines are investigated. A three-dimensional numerical model adopting an empirical global reaction mechanism for the Pd-Rh dual-carrier catalytic converter is established. The results show that the conversion efficiency slightly increase with the increase of the carrier cell density ratio, the maximum conversion efficiency differences of CH4, CO and NO are 5.7 %, 8.3 % and 7.9 %, respectively. When the carrier wall thickness decreases from 0.24 mm to 0.10 mm, the conversion efficiencies of CH4, CO and NO slightly increase, and the maximum differences are 5.5 %, 8.0 % and 8.0 %, respectively. Additionally, the fuzzy grey relational analysis (FGRA) is employed to make a comprehensive evaluation. For the conversion efficiencies of CH4 and NO, the primary and secondary relationships of the influence factors are carrier diameter > carrier length > carrier cell density ratio > carrier wall thickness. The orthogonal experiment analysis indicates that case 7 shows the best total conversion performance (CH4: 91.9 %; CO: 99.7 %; NO: 83.9 %) at 673K. Compared with the baseline case 2, the conversion efficiencies of CH4 and NO are increased by 14 % and 19.9 %, while the volume increased by 36.1 %.