Ouiminga et al / Chemistry Journal (2012), Vol. 02, Issue 05, pp. 166-173 ISSN 2049-954X Available online at www.scientific-journals.co.uk 166 Research Paper Characterization of Carbonaceous and Nitrogenous Species during the Reductive and Oxidative Combustion of Biomass: Case of Millet Stalks Salifou Koucka Ouiminga 1 *, Thomas Rogaume 2 , Arsène H. Yonli 1 , Alfa Oumar Dissa 1 and Jean Koulidiati 1 1 Laboratory of Physics and Chemistry of Environment, University of Ouagadougou; 03 BP 7021 Ouaga 03, Burkina Faso Tel.: (226) 50 39 38 15; Fax: (226) 50 39 33 37 2 Prime Institute, Dept. Fluid, Thermal, Combustion, (UPR 3346 CNRS), ENSMA – Teleport 2, 1 Avenue Clement ADER, BP 40109, 86961 FUTUROSCOPE cedex, France Tel.: (33) 549498290; Fax: 0549498291 *E-Mail: salifou_ouiminga@univ-ouaga.bf Abstract Millet stalks are used as fuel in pottering crafting in Africa. A study was conducted to characterize the gaseous species produced during the reductive and oxidative combustion of millet stalks. The experiment was carried out on temperature ranging from 800-1000 o C, using the tubular furnace, coupled with two gas analyzers i.e. Analyzer Fourier Transforms Infrared (FTIR) analyzer and a non-dispersive infrared (NDIR) as experimental apparatus. The gaseous products analyzed are i.e. CO, CO 2 , CH 4 , C 3 H 8 , C 2 H 4 , C 2 H 2 , C 6 H 6 , HCN, N 2 O, NO, NO 2 and NH 3 . The results show that, in reducing conditions, the levels of carbon monoxide (CO), methane (CH 4 ) and acetylene (C 2 H 2 ) are increasing functions of temperature, while emissions of CO 2 and benzene (C 6 H 6 ) decrease as the temperature increases. Emissions of other compounds were remained relatively stable. Reductive combustion produced various compounds like CO 2 , CO, N etc. while oxidative combustion produced compounds like light hydrocarbon, benzene etc. The over all efficiency of conversion was found about 15%. Keywords: Combustion, Millet Stalks, Carbon, Nitrogen 1. Introduction In Burkina Faso, agriculture is the most popular activity. It supports more than ten million people and is practiced by over 84% of the workforce. However, the rainy season lasts only four months a year, forcing farmers to engage in ancillary activities, such as pottery. This activity requires the use of furnaces, usually constructed of clay. These kilns have various geometries, classified the type I to type V (Daho, 2004). Our study focused on the ovens of type III. These are natural draft furnaces and upward. Each one has an opening up, which sometimes appears as a chimney for smoke evacuation. In these ovens millet stalk is used as a fuel. However, burning in pottery kilns may be a source of pollution, especially in gaseous form. The exhaust emissions consist mainly of oxides of carbon, sulphur, nitrogen, chlorine products (dioxins and furans), volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs), dust, etc. (Daho, 2004; Ouedraogo et al, 2007 and Ouiminga et al, 2009). The fuel is mainly composed of carbon, oxygen, hydrogen and nitrogen. The species analyzed are: CO, CO 2 , CH 4 , C 3 H 8 , C 2 H 4 , C 2 H 2 , C 6 H 6 , HCN, N 2 O, NO, NO 2 and NH 3 . HCN and NH 3 are important intermediates for the formation of fuel NO, (De Soete, 1974; 1989; Morley, 1976; 1980; Miller et al, 1983; 1984 and 1989), while the NO 2 and N 2 O are involved in the reduction of NO (Miller