Toluene microwave cracking and reforming over bio-char with in-situ activation and ex-situ impregnation of metal

Removal of biomass tar is of importance for biomass gasification technology, since the existence of tar can cause tremendous problems, such as lowering heat transfer efficiencies and blocking the filters and pipes, etc. A typical one-ring aromatic hydrocarbon (i.e., toluene) is chosen as model compounds to investigate tar cracking and reforming performance with microwave heating, catalyzed by biomass-derived char (Bio-char). The adopted chars consist of original char obtained by microwave or electrical heating, an in-situ activated char as well as metal-impregnated char. For the cracking process, original char achieved with microwave heating exhibits better catalytic activity, compared to that achieved with electrical heating. It is further compared activated char is more active to toluene cracking and an activated char impregnated by Ni shows the most desirable performance to this process. A process of mixed reforming comprised by steam and dry reforming presents an evident superiority in terms of toluene conversion and catalyst stability, which can achieve an average conversion of 95.19% and a minor mass loss of 2.2% occurred in the used char during 120 min. It is calculated energy efficiency of a microwave-assisted combined reforming system at lab-scale is up to 57.8%. (C) 2019 Elsevier Ltd. All rights reserved.