Studies of the Brazilian sugarcane bagasse carbonisation process and products properties

Laboratory-scale experiments in an enlarged scale thermoreactor have demons trated that the pyrolysis of the bagasse bulk in a mechanically loosened la yer yields 23-28% charcoal measured on an oven dry basis. The charcoal is a ppropriate for the production of fuel briquettes and granules for household and industry uses. To implement an energy self-sufficient production proce ss, yields of condensable matter and gas components were determined. It is shown that their combined heat of combustion exceeds the upper limit of the heat necessary to carbonise the biomass by 1.6 to 1.8 times. To overcome t he difficulties caused by a high fine particles content and the fibrous str ucture of bagasse, the use of a rotary drum type apparatus is suggested to be appropriate. Due to technological considerations, a two-stage process ma y be recommended: a heating up and pyrolysis stage up to 350 degrees C, and a charcoal glowing stage with the peak temperature 475-500 degrees C. Such a reactor unit with a joint furnace and closed pyroligneous vapour and hea t carrier flow system, greatly reduces the emission of carbon monoxide (CO) and dust particles. Bagasse can be used as an alternative source of tradit ional wood for charcoal production. It could prevent the deforestation of n ative forests. (C) 1999 Elsevier Science Ltd. All rights reserved.