Manufacture of densified solid biofuels (Briquettes) made of acacia sawdust and cattle manure in the region of Cordoba

Abstract

In Colombia around 460,000 households lack of electricity, 4% of the total population. The department of Córdoba has approximately 1.9 million livestock, which annually translates to 4.2 million tons of manure and presents an emerging market of sawmills. This work assesses the physicochemical and energetic properties of briquettes made with mixtures of acacia sawdust and cattle manure from the department of Córdoba are evaluated, carrying out tests and analytical calculations. First the sawdust-manure mixture percentage is determined, these were established by an experimental simplex lattice design. The process begins with the drying and crushing of the biomass where the final humidity is less than 12% and grain size of 2mm. Then the mixtures are compacted in a semi-automatic briquette machine. After, the tests of compressive strength and mechanical durability are carried out, with these the manageability of the briquettes is determined. Through the proximal-elemental analysis, the calorific value and the sulfur emissions are analytically calculated, and through the boiling water test, the energy efficiency is evaluated. Moreover, it was found the most favorable mixture in terms of the results of the previous tests, giving as outcome the briquette with 60% manure. Finally, the most favorable briquette is subjected to a gasification process in a Downdraft gasifier in three valve positions, half closed, half and fully open, in order to find the properties of the gas produced by the briquette. The result of the gas gives a CV of 1556 kJ/kg and a generation power of 11.8 kW.