Rapid pyrolysis of brown coal in a drop-tube reactor with co-feeding of char as a promoter of in situ tar reforming

► A potential decoupled gasification process with downer reactor was proposed. ► The first study on tar reforming over char underconditions expected in the downer. ► A drop-tube reactor was used to simulate the downer reactor. ► Tar was significantly decomposed via a volatile-char interaction. ► Increasing temperature, feeding rate, and char ratio enhanced tar decomposition.