CO2 as a 'Soft' Oxidant for Syngas Production via Chemical Looping

摘要

‘Chemical Looping Combustion’ is a clean combustion technology, which enables fossil fuel combustion with inherent CO2 capture based on the cyclic oxidation and reduction of an oxygen carrier. While most efforts in chemical looping (CL) are focused on combustion, we previously demonstrated the application of the 'CL principle'-the periodic oxidation and reduction of a metal oxide to couple two independent redox reactions-to the activation of CO2 via reduction to CO. In the present contribution, we investigate and compare CO2 activation via CL in two different operating modes: In the first scheme, CO2 reduction is coupled with CH4 oxidation by using mixtures of Fe and Ni (as alloys or simple physical mixtures) to produce CO and syngas product streams. In the second operating scheme, monometallic Ni carriers are utilized to catalytically crack CH4, producing pure H2 streams. The solid carbon deposits are then burnt off with CO2, overall producing separate CO and H2 product streams.