Heterogeneous Catalysts from Natural Sources for Tar Removal: A Mini Review

Tar formation in gasifier is a headache problem in biomass gasification process. Catalytic cracking and/or reforming of tar using a catalyst is the most effective way to solve this problem. In order to reduce the cost, some heterogeneous catalysts from natural sources have been found to possess excellent catalytic properties that render them suitable for tar cracking and reforming in biomass gasification process. This article reviews the main natural catalysts such as dolomite, olivine, coal/biomass char and waste scallop shell that have been evaluated for tar removal in biomass gasification till date. Especially, our investigations on waste scallop shell based catalysts are reviewed in more details. The ways to improve the catalytic activity and appropriate options for a practical process are also reviewed and discussed. It is expected to provide the basis for a proposal for the exploitation of heterogeneous catalysts from natural sources to optimize tar removal in biomass gasification