Experimental investigation of tar recycling in pilot-scale down-draft biomass gasifiers: prospects, operating procedures, process variations, and controls

Abstract

Tar is considered the main barrier to commercial power generation when using biomass gasification as it causes serious environmental issues, even after incorporating an efficient removal system. Moreover, the existing tar compositions contain high energy levels, thus lowering the heating value of produced syngas. In this paper, tar was blended with three types of plain biomass at ratios up to 10%; biomass and tar were gasified together at different equivalence ratios. Tar recycling was found beneficial to the syngas compositions. The size distribution of the biomass feed and the gasified char were studied. Experimental evidence shows that the isolation time of the shutdown procedure is proportional to the volume of the gasifier cores. This paper discusses the operation procedure and troubleshoots biomass gasifiers in detail, providing useful guidelines for future practical research.

Graphical Abstract

Keywords:

• Renewable fuel
• biomass conversion
• tar circulation
• syngas production

Disclosure statement

No potential conflict of interest was reported by the authors.