High-pressure kinetic interactions between CO and H2 during syngas catalytic combustion on PdO

The catalytic combustion of H2/CO/O2/N2 mixtures over PdO was investigated at pressures 3 to 10 bar, H2:CO volumetric ratios 1:5 3:1, and global equivalence φ = 0.13 0.23. catalyst surface temperatures were controlled 540–690 K, a range especially important for hybrid hetero-/homogeneous approaches with large gas turbines idle or part-load operation microreactors recuperative small-scale turbines. In situ Raman measurements determined the major gas-phase species concentrations boundary layers in channel-flow reactor, thermocouples monitored temperatures, characterization identified oxidation state (PdO) morphology. A 2-D CFD code detailed reaction mechanism simulated experiments. Simulations individual fuel components revealed pressure dependencies ∼p0.74 ∼p0.10 CO H2 reactivities, respectively, ratios. H2/CO blends, transition (TTRAN) identified, below (above) which inhibited (promoted) chemically CO. decreased increasing ratio, pressure, ratio. Sensitivity analysis indicated that O2 adsorption reactions had larger inhibiting effect on oxidation, particularly lower pressures. Comparisons other noble metals showed higher than those Pt Rh. Even though this behavior favored Rh ignition syngas practical burners, kinetic coupling (H2 inhibition) considerably weaker T < TTRAN, thus rendering also potentially suitable low temperature ignition.