Simulation of Sugarcane Residues Co-Gasification (Vinasse-Straw-Bagasse) for Different Equivalence Ratios and Gasifying Agents

Abstract

This study evaluates the co-gasification of the main residues of the sugarcane industry (vinasse, bagasse and straw), in order to recover their energy and give an appropriate destination, making them suitable for use as fuel gas (syngas). To verify the feasibility of energy conversion through gasification, thermodynamic equilibrium model for gasification process was carried out and verified by literature available data. The gasification parameters for different gasification agents and equivalence ratio values were then obtained, such as: syngas composition and energy content, operating temperature, production rate and conversion efficiency. For equivalence ratios (ER) between 0.35 and 0.4 and temperatures around 750 °C, the quality of the syngas obtained is better, but a higher energy content is obtained in ER values of 0.2. There is a high H2/CO ratio for the gasifying agent formed by air and steam, and when using oxygen-enriched air, there is a change in the ER value that generates better syngas quality (to 0.3–0.35) and an increase in its energy content. There is also a possible better return on investment in a thermoelectric plant for the lowest ER values, which can increase gains by up to 21.4% and decrease the installation’s payback. The results indicate that the co-gasification of the waste is feasible, allowing a better use of its energy potential.