Improvement of kiln design and combustion/carbonization timing to produce charcoal from agricultural waste in Developing countries

Abstract

Current economic conditions in third world countries like Haiti are so poor that the majority of the population has no access to energy sources that people in the first world take for granted. In Haiti the last two percent of the forests are being cut down to provide energy for basic cooking to survive. In response to the situation, MIT professors and students are designing a multi-step process for making charcoal briquettes from local agricultural waste products, or biomass. The process involves the combustion and carbonization of biomass at sustained high temperature in an air-tight metal barrel kiln to produce char. The char produced from Haiti's main agricultural waste product, bagasse, must be powderized, mixed with a binder, compressed into briquettes, and finally baked. The purpose of the thesis was to improve on key areas of the charcoal making process. The goals were to: conduct and investigation into alternative kiln layouts; address safety concerns with water boiling, briquette baking, and bottom venting; design of a method for uniform and complete briquette baking using heat from the carbonizing kiln; and gain a better understanding of the importance combustion timing and sealing.

(cont.) Design for affordable, low level manufacturing would be an important requirement as well. The results of the thesis were: an analysis of possible kiln designs based on the supplies typically available in developing countries; improvements to safety by using wire tethers on kiln hardware to allow kiln operators to keep a safe distance; a proposed new design for a briquette baking box with multiple briquette banks; and combustion timing and kiln insulation techniques to maximize char output.