Bench-Scale Testing of Coal Conversion Using Moving Bed in Coal Direct Chemical Looping Process

In comparison with gaseous fuel looping processes, the coal direct chemical looping (CDCL) process directly converts coal in the reducer, eliminating the need for the gasifier and air separation unit (ASU).  A bench scale moving bed reactor was used to study the coal conversion. In a typical test, a mixture of oxygen carrier particles and solid fuel was introduced via a Y-shaped pipe. The particle was then steadily moved downward through the heated zone where it reacts with the coal powder. Meanwhile, the enhancing gas CO₂ was introduced into the system together with carrier gas N₂. During the experiment, the bottom screw continuously conveyed the solids from the reactor into a funnel below the screw feeder at a pre-calibrated rotational speed. Almost complete coal conversion could be achieved using the composite iron oxides particles. Various post-experiments have also been conducted on iron oxides particles. The operational results prove that a moving bed reactor design is favorable for CDCL application.