Combustion of Sugarcane Bagasse Pellets Produced with/without Glycerol: Chemical, Thermal and Emission Analyses

Abstract

Purpose: Use of agricultural biomass in the form of pellets has gained worldwide prominence in recent decades, as part of the search for cleaner and renewable energy sources. Brazil is the largest sugarcane producer in the world, a fact that also places it as a major producer of residues from processing this crop. Methods: In this study, sugarcane bagasse pellets (SBP100) were handcrafted using glycerol as binder (30% - SBP30G) and, subsequently, analyses of their chemical and thermal properties, as well as those of the thermal decomposition exhaust gases, were conducted. Results: Average temperatures in the combustion range were 213.62±137.07° C (SBP100) and 211.97±86.85 °C (SBP30G). Combustion exhaust gas values were 20.04±0.15% (SBP100) and 19.95±0.19% (SBP30G) for O₂; 1739.58±156.17 ppm (SBP100) and 1575±466.85 ppm (SBP30G) for CO; 19.92 ± 2.47 ppm (SBP100) and 17.33±4.69 ppm (SBP30G) for NOx; 341.67±134.37 ppm (SBP100) and 491.67±341.42 ppm (SBP30G) for CH₄. SBP30G combustion proved to be less polluting with respect to CO and NOx generation than SBP100, but not for CH₄. However, average thermal performance was similar for both. Conclusion: Use of glycerol contributed considerably to the changes in the pellets’ physical parameters. Exhaust gas analyses of the combustion of these substrates can serve as a basis for creating safety parameters and public policies to regulate the use of biomass for energy purposes.