화학공학소재연구정보센터
Energy & Fuels, Vol.27, No.8, 4119-4128, 2013
Application of the Moving-Bed Chemical Looping Process for High Methane Conversion
The syngas chemical looping (SCL) process has been demonstrated at The Ohio State University for the conversion of gaseous fuels, such as natural gas and syngas, to sequestration-ready carbon, dioxide (CO2) and high-purity hydrogen (H-2) in a 25 kWth sub-pilot-scle unit operation. The present work focuses on parametric studies of the unique moving-bed reducer reactor operation for the conversion of methane to a concentrated stream of CO2. The variables studied include the operating temperature, the gas hourly space velocity (GHSV), and the oxygen carrier/methane mass flow ratio. The results show that nearly full methane conversion, (similar to 98%) can be achieved in the process with a GHSV of 395 h(-1). Additionally, the post experiment oxygen-carrier analysis indicated that the oxygen-carrier conversion reached nearly 50%. Comparatively, the resulting oxygen-carrier conversion for the moving-bed reducer design is nearly 5 times greater than that theoretically achievable in a fluidized-bed reducer. The oxygen-carrier conversion profile along the height of the bed indicates that the conversion from Fe3O4 to FeO occurs at a much faster rate than the conversion from FeO to Fe in the reactor system. A multi-stage equilibrium simulation and model for the reducer performance was developed using ASPEN Plus to compare against the experimental results. The simulation and experiment show a good match for oxygen-carrier and methane conversion results based on the testing conditions used. The parametric studies performed show promising results, indicating that the SCL technology can be used for the conversion of natural gas with CO2 readily separated.