Properties of Charcoal from Five Exotic High Land Tree Species Using a Modified Two-Step Carbonization Method

Abstract

            This research focused on the properties of high-quality charcoal derived from High Land Exotic tree species (HETS) planted under a reforestation program in the Angkhang Royal Agricultural Station. Five potential species namely, Cinnamomum camphora (L.) Presl, Prunus cerasoides D.Don, Liquidambar formosana Hance, Fraxinus griffinthii C.B. Clarke, and Acacia confusa Merr. were selected. These trees were carbonized by applying a new technique (called the two-step carbonization) through modified 200-liter charcoal kilns (KP1 and KP2), made in our previous works. After carbonization, the charcoal properties were studied by comparing their fuel and adsorption properties. This included Proximate Analysis, Ultimate Analysis, Calorific Value, and Iodine Number. The results indicated that both types of charcoal kilns had no significant difference with regards to the means of fuel and adsorption properties. The moisture content of A. confusa had the lowest mean and the highest mean C. camphora at 4.70% and 6.81%, respectively. The volatile compound value of C. camphora had the lowest mean and A. confusa had the highest mean at 6.22% and 12.35%, respectively. The mean ash value of A. confusa was the lowest at 2.33%, while C. camphora had the highest means at 5.86%. Fixed carbon values of L. formosana and C. camphora had the lowest and highest mean at 77.00% and 81.11%, respectively, which is consistent with the ultimate analysis of carbon element percentage. The mean calorific value of L. formosana was the lowest at 6,942.2 cal/g and A. confusa had the highest mean at 7,458.9 cal/g. The Iodine adsorption number was between 472.26 - 689.31 mg_iodine/g_charcoal, which was higher than the average Iodine adsorption number of typical wood charcoal and close to the minimum activated carbon of 600 mg_iodine/g_charcoal.