Syngas production by chemical-looping gasification of waste activated carbon with iron-based oxygen carrier

Waste activated carbon (WAC), as a typical solid waste, can be utilized by chemical looping gasification (CLG) technology with an iron-based oxygen carrier to produce valuable synthesis gas. A series of experiments on WAC of the CLG process have been carried out in a fixed-bed reactor. The operation parameters involving the OC/WAC mole ratio, steam flow rate and reaction temperature during CLG reactions have been investigated in detail. Further, the cyclic performance within 10 cycles has been also discussed. Fresh and cyclic reaction oxygen carrier samples have been analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). In order to obtain high-quality syngas with high carbon conversion, the optimal of OC/WAC mole ratio, steam flow rate and reaction temperature are 0.15, 0.10 mL/min, and 950 °C, respectively. The iron-based oxygen carrier exhibits a stable cyclic performance during the multiple tests, following the reaction path of Fe 2 O 3 →Fe 0.98 O in the individual reduction process. Moreover, the iron-based oxygen carrier could be oxidized almost to its initial state after 10 redox tests. No obvious sintering and agglomeration phenomena are observed. The WAC of CLG presents a new approach for the comprehensive utilization and disposal of solid waste, especially with low volatile feedstock.