Performance Assessment of an Allothermal Auger Gasification System for On-Farm Grain Drying

Abstract

Biomass gasification is a well-developed technology with the potential to convert agricultural re sidues to value-added products. The availability of on-farm gasifiers that can handle low-density agricultural wastes such as soybean residue, an underutilized feedstock, is limited. Therefore, the goal of this research was to install and assess an allothermal, externally heated, auger gasifier ca pable of converting agricultural wastes to combustible gas for on-farm grain drying. The system was used to convert soybean residues under different reactor temperature, i.e. , 700 ° C, 750 ° C, 800 ° C, and 850 ° C. The results showed that increasing the reactor temperature from 700 ° C to 850 ° C increased the producer gas molar fractions of H 2 , CO, and CH 4 , from 1.1 % to 1.5 % , from 15.0 % to 23.8%, and from 5.1 % to 7.7%, respectively. The higher heating value of the producer gas reached 6.3 MJ/m 3 at reactor temperature of 850 ° C. Specific gas yield increased from 0.32 to 0.58 m 3 /kg biomass while char and particulate yield decreased from 41.7 % to 33.6% by increasing the reactor temperature from 700 ° C to 850 ° C. Maximum carbon sequestration achieved, in the form of biochar-carbon, was 32% of the raw feedstock carbon. Gasification of collectable soybean residues from 1 acre would be sufficient to dry 1132 kg of soybean seeds (the average yield from one acre)