Small-scale downdraft gasifiers for biomass gasification: A review

Downdraft gasifier is very attractive for biomass gasification due to its easy fabrication and operation, and also due to low tar content in producer gas. However, drawbacks such as grate blocking, channeling, and bridging are found in the downdraft gasifiers, typically for feedstock with low bulk density. Another disadvantage is the downdraft gasifiers only suitable for feedstock with low moisture content. The design of the gasifiers is an important parameter that affects their performance. Various works on design improvements have been done for enhancing the performance of the gasifiers. This paper aims to review small-scale downdraft gasifiers for biomass gasification which is focused on design improvements and their effect on the performance of the gasifiers. Many works from previous researchers have been studied and cited. The result shows that the design of the gasifiers is an important parameter in gasification, besides biomass feedstock characteristics and process parameters.