Syngas Production by Chemical-Looping Gasification of Waste Activated Carbon with Iron-Based Oxygen Carrier

Abstract

Waste Activated Carbon (WAC), as a typical solid waste, can be utilized by Chemical-Looping Gasification (CLG) technology with an iron-based Oxygen Carrier (OC) to produce valuable synthesis gas. A series of experiments on WAC of the CLG process has been performed in a fixed-bed reactor. The operation parameters and cyclic performance of the iron-based OC have been investigated during CLG reactions. Fresh and cyclic reaction OC samples have been analyzed by X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). To obtain high-quality syngas with high carbon conversion, the optimal OC/WAC mole ratio, steam flow rate and reaction temperature are 0.1, 0.10 mL/min, and 950 °C, respectively. The iron-based OC exhibits a stable cyclic performance during multiple tests, following the reaction path of Fe₂O₃ to Fe_0.98O in the individual reduction process. Moreover, the iron-based OC is oxidized to almost its initial state after 10 redox tests without obvious sintering and agglomeration phenomena. The WAC of CLG provides a new approach to the comprehensive usage of solid waste, especially with low volatile feedstock.