Desenvolvimento de molde para produção de briquetes e análise de biomassas

Abstract

There is a Brazilian context of strong energy dependence on biomass. However, there is little diversification of raw material and the country has several underutilized agricultural wastes. Thereby, this work aimed to develop a low-cost prototype die for briquetting at bench scale, in order to enable the research of other materials for briquetting, besides analyzing how the compression pressure affects the quality of the briquettes produced and to test some alternatives of agricultural residues found in Ceará. Two different prototypes were produced for 10 ton load. One of them met the objectives required, being possible to manufacture on a metal lathe, with safety factor for static load of 1.7811, and an estimated cost of R$2.693,20 for the SAE 304 stainless steel die, and R$2.032,50 for the die using SAE 1020 and 1045 carbon stell (prices relative to January 2019, without considering taxes on products and services). Then the influence of compaction pressure on the high calorific value (HCV) of sugarcane bagasse briquettes was analyzed. Starting from 12.7MPa, the HCV only varied significantly reaching the value of 38.3MPa, varying from 15,757 to 15,962 MJ/kg (increase of 1.3%), thus having little variation with the pressure. In contrast, the density and consequently the energy density were very sensitive to the variation of pressure. Between the same pressure ranges the density varied from 148,0004 to 213,0537 g/m3 (variation of about 44%), and the energy density varied from 2,332 to 3,401 MJ/m3 (variation of about 46%). Of the agricultural wastes analyzed, the maize straw could not be briquetted in the compaction die, even in a blend with sugarcane bagasse. The garlic skin briquette even when blended with sugarcane bagasse did not have enough advantages to justify its briquetting, presenting a HCV of 13.6864 MJ/kg for garlic skin only and 14.7188 MJ/kg in mixture, although it could be used for briquetting blended with materials of greater energy potential. The rice husk was possible to briquette in blend with the sugarcane bagasse and showed several advantages after briquetting, such as lower ash content and higher volatile matter when compared to in natura rice husk, presenting HCV of 15.0444 MJ/kg.