Rice consumption in sub-Sahara Africa (SSA) increased from about 24.7 to 26.2 million tons between the period 2012 and 2015. During the same period paddy production increased from 20.6 to 23.5 million tons. Increase in rice production translates to an increase in rice milling by-products of which rice husk is one of them. About 5 million tons of rice husk was produced in 2015 as this milling by-product constitutes 20-22% of the paddy grain. To disseminate rice husk in rice-growing environments in Africa through the production of renewable thermal energy with less smoke for cooking, a water boiling test protocol was used to compare four fan-assisted rice husk gasifier cookstoves [Rua (RRHS), Viet (VRHS), Paul Olivier 150 (PO150) and Paul Olivier 250 (PO250)] in comparison with a natural draft gasifier [(Mayon (MYN)]. Workplace emissions were compared for different cookstoves and burner types (pore and vent). Furthermore, the effect of mixing different proportions of rice husk and palm kernel shell on burning time and flame temperature was investigated. The feasibility of disseminating these cookstoves was evaluated by end-users using the controlled cooking test protocol. Fan-assisted cookstoves with vent-type burners were safer to use as they produced both lower concentrations of flue gases and particulate matter. The fan-assisted cookstoves also recorded better thermal indices. Rice husk mixed with palm kernel shell at varying proportions burned for a longer time than rice husk only, but this mixing had no effect on flame temperature. End-user preferred fan-assisted (RRHS, VRHS, PO150/250) gasifiers to the Mayon natural draft gasifier cookstoves (Ndindeng et al. 2019). Gasifier cookstove acceptability was positively correlated with five stove descriptors making them important in future fine-tuning and design.

 

Reference

Ndindeng, S. A., Wopereis, M., Sanyang, S., Futakuchi, K. (2019). Evaluation of fan-assisted rice husk fuelled gasifier cookstoves for application in sub-Sahara Africa. Renewable Energy 139:924-235. https://doi.org/10.1016/j.renene.2019.02.132.

Technical drawings for PO150 gasifier cookstoves can be downloaded here. Drawings of other stoves can be requested from the Africa Rice Center (S.Ndindeng@cgiar.org).