Study of the Physical, Chemical and Thermal Potential of Biochar Produced from Agricultural Residues in Faranah, Republic of Guinea

The objective of this study is the valorization of agricultural residues in the production of biochar in Faranah. The availability of plant material made it possible to process the rice bran and peanut shell on site. The rice bran was directly used after drying in the sun for 72 hours. The peanut shell after sun-drying for 72 hours was processed by pyrolysis using a barrel carbonizer. The operating speed of a single barrel carbonizer is characterized by small bottom openings 25% air holes, a 50% upper cylindrical opening for the exit of charred material. The carbonization time is 1h15mn. A manual experimental retor press was designed for the manufacture of cylindrical bio-charcoal briquettes. Analysis of the raw dry matter of rice bran and peanut shell yields highly microporous materials of elemental composition, rice bran: Carbon (C) = 34.85%; Hydrogen (H) = 4.10%; Oxygen (O) = 33.67%; Nitrogen (N) = 1.13%; Ash content (Tc) = 12.25%; Volatile matter (Mv) = 14% and a moisture content (Th) = 11.45%. Elemental analysis of the peanut shell gives the following results: Carbon (C) = 38.85%; Hydrogen (H) = 6.02%; Oxygen (O) = 32.54%; Nitrogen (N) = 1.95%; Ash content (Tc) = 8.79%; Volatile matter (Mv) = 11.85%, moisture content (Th) = 6.85%. This made it possible to make different mixtures to obtain biochar according to a proportional percentage composition. The most efficient from an energy point of view is: Clay (A) + Rice Bran (SR) + Peanut Rooster (CA) = (A20% + SR20% + CA60%) with the elementary fraction: Carbon (C) = 38.25%; Hydrogen (H) = 5.85%; Oxygen (O) = 48.90%; Nitrogen (N) = 0.65%; Ash content (Tc) = 6.35%; and a humidity level (Th) = 6.85%; Calorific value (PC) = 16 (MJ / kg). These different results show that the biochar produced can be used as an alternative energy source for cooking food.