A non-premixed reactive volatilization reactor for catalytic partial oxidation of low volatility fuels at a short contact time

This work presents a novel non-premixed opposed-flow reactive volatilization reactor that simultaneously vaporizes and partially oxidizes low volatility liquid hydrocarbons at a short contact time (<12 ms). In the reactor, a catalyst-coated metal mesh is placed interstitially between an air duct and a liquid pool. Low-volatility fuels are evaporated by radiative and convective heating and combine at local stoichiometry determined by the axial location of the mesh. Experiments were conducted with n-dodecane at different local molar carbon-to-oxygen ratios (C/O) and inlet airflow. Platinum and rhodium coated mesh substrates were the active materials for performing partial oxidation. A 1D opposed-flow similarity model based on the canonical opposed-flow combustion solution was created to simulate the axial temperature and species concentration along the reactor centerline. Results show that the reactor vaporized and converted n-dodecane to reformed products at a global molar carbon-to-oxygen ratio (C/O)(g) of up to 3.46. However, the local mixture depended on mesh axial position, with (C/O)(mesh) ranging from 0.2 to 3.94 for platinum and 0.31 to 4.97 for rhodium. It was found that the local stoichiometry at the mesh surface plays a more important role than the global one since no gas-phase reactions occurred outside the mesh region. Overall, our work demonstrates that non-premixed catalytic reactive volatilization is a promising technique to investigate fundamental concepts in hydrocarbon reforming and can offer insights into designing practical short-contact time reactors that can have high conversion and selectivity but low surface carbon deposition tendency at high C/O.

Automated summary

This study introduces a novel non-premixed opposed-flow reactive volatilization reactor for vaporizing and partially oxidizing low volatility liquid hydrocarbons at short contact time, with potential for high conversion and selectivity. Experimental and modeling results reveal the importance of local mixture determined by mesh axial position and local stoichiometry at the mesh surface over global one.