Prototype development of small scale transportable fuel production system for agricultural byproducts

Abstract

The objective is to study the potential of peanut shell waste and cassava rhizome conversion using a modular fixed bed gasifier coupled with thermal integration unit. The thermal integration unit improved gasification reaction in which lower tar content and high gas production efficiency can be achieved. The air flow rate had integrated effects on product yield and composition; higher air flow rate resulted in higher gas yield with less tar and char. The result from peanut shell gasification indicated the optimal conditions without catalyst addition at air flow rate of 3.06 m3/hr where carbon and hydrogen conversions were 87.10% and 57.21%, respectively. The lower heating value and cold gas efficiency were 3.95 MJ/m3 and 56.10%, respectively. In case of cassava rhizome, carbon and hydrogen conversion were 92.36%, and 65.92%, respectively at 2.5 m3/hr air flow. The lower heating value and cold gas efficiency were 4.46 MJ/m3 and 54.86%, respectively.

For improve quality of product gas from gasification, the 5%Ni/char and 5%Ni/dolomite catalyst enhanced condensable tar reforming to smaller gases resulting in increased gas heating value and cold gas efficiency with greater synthesis gas yield. The 5%Ni/dolomite catalyst can be employed as both the tar filter and also enhanced catalytic cracking reactions. With product gas connection to a generator, the conversion to electricity was 11.03% with peanut shell and 11.29% with cassava rhizome. The efficiency of the gasifier-cogeneration system from peanut shell and cassava rhizome waste was 11.84% and 12.12%, respectively. The predicted gas composition results from ASPEN PLUS simulation model for peanut shell waste were better than those of cassava rhizome. Generally, developed model is able to simulate the performance of the gasifier with acceptable gas yield estimation.