Performance studies on a downdraft biomass gasifier with blends of coconut shell and rubber seed shell as feedstock

The use of biomass gasification system for the generation of combined heat and power has gained importance because it is considered to be one of the most promising renewable energy technologies. Widespread research has been already carried out on downdraft gasifier with single biomass as feedstock. However limited work is available to ascertain the feasibility of utilising blends of biomasses. In this paper, theoretical and experimental studies have been carried out on a 50 kWth downdraft gasifier with the blends of coconut shell and rubber seed shell, which are available abundantly in the rural villages of South India. Two-Zone kinetic modelling is followed for the theoretical studies. Experimental study has been carried out to prove the validity of the modelling approach. The results show that the mixing of rubber seed shell and coconut shell with various compositions yields the performance which is on par with the woody biomasses. Besides, the maximum values of the performance parameters are obtained when the equivalence ratio is maintained between 0.2 and 0.3.