Effect of soaked biomass on gasification temperature performance in an open-downdraft gasifier

[Display omitted] •Gasification of soaked biomass can be carried out hardwood produces a temperature of 700–1000 °C, and the gasification zone is relatively stable.•Softwood, fibrous, and hygroscopic biomass experienced a significant decrease in temperature, position, and area of the gasification zone.•Flat or flattened shaped biomass produces better gasification temperature performance than cylindrical and hemispherical shapes.•The size, shape, and nature of biomass affect the gasification temperature performance of suction pressure soaked biomass. Gasification of soaked biomass is a novel approach to saving cost and time of conditioning feedstock. It may have disadvantages on gasification temperature since an open-downdraft gasifier requires a zone with high temperature to maintain endothermic gasification processes. Heat is generated by exothermic reaction in the gasifier. It is supposed to be used by the gasification reactions, and excess water use it too. Ten varieties of biomass with different properties, shapes, and sizes were soaked and utilized as gasification feedstocks. The gasifier was able to maintain a stable temperature above 800 °C when fed soaked hardwoods, unlike soaked softwoods, which made the gasifier unable to maintain a temperature higher than 700 °C. Small, flat-shaped soaked biomasses were able to maintain high temperatures better than that of other-shaped biomasses. Particularly, soaked bamboo and soaked coconut shell made the gasifier able to maintain a high temperature zone of more than 1,000 °C.