Parametric Analysis of a Gasification-Based Cookstove as a Function of Biomass Density, Gasification Behavior, Airflow Ratio, and Design

Abstract

The energy performance and emissions (carbon monoxide and total suspended particulate matter) of a biomass gasification-based cookstove under a modified water boiling test (WBT 4.2.3 protocol) were characterized here. The controllable process parameters analyzed were the biomass bulk density (pellets-WP and chips-WCH) and the combustion-air/gasification-air ratio (2.8, 3.0, and 3.2). Moreover, a design parameter of the cookstove was analyzed through two combustion chamber designs (combustion chambers 1 and 2). The cookstove was characterized in detail considering the complete cookstove (control volume 1), the combustion chamber (control volume 2), and the gasification process (control volume 3). The cookstove reached an average efficiency of 25.2% for pellets and 24.1% for chips. The best behavior for the cookstove was achieved when pellets were used, which is attributed to their higher bulk density and to the fact that during their gasification process, the biochar yield was 12% higher, while the biomass consumption decreased by 16% compared to the chips. The carbon monoxide specific emissions were 2.78 g/MJdfor pellets and 2.75 g/MJdfor chips. On average, the cookstove released total suspended particulate matter between 74.11 and 122.70 mg/MJd. The cookstove low emissions are ascribed to the proper combustion air flow and the combustion chamber design, which favored the mixing between producer gas and combustion air.