Exergy and environmental ranking of bioethanol production routes.

Author(s)

Pablo Andres Silva Ortiz

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Escola Politécnica (EP/BC)
• Defense date: 2016-10-10

Examining board members

Silvio de Oliveira Junior; Marina Oliveira de Souza Dias; Luiz Felipe Pellegrini; Silvia Azucena Nebra de Pérez; Marcelo Modesto da Silva

• Advisor: Silvio de Oliveira Junior

Abstract

Currently, electricity generation and second-generation bioethanol production from lignocellulosic materials represent technological alternatives in the sugar-energy sector. Nevertheless, the introduction of new production processes represents a real challenge due to the complexity and diversity of the technological routes that can be evaluated. In addition, there are economic and environmental factors that must be considered during the development and consolidation of these new configurations. Accordingly, this project aims to develop a methodology to perform the exergy and exergo-environmental analysis, evaluation and ranking of processes in order to obtain ethanol and electricity from sugarcane in different biorefinery configurations. Hence, operating technical data of each technological route were adopted as well as the environmental aspects of using these systems. The proposed models assessed the Conventional (Case 1), Biochemical (Case 2) and Thermochemical (Case 3) routes using simulation programs and mathematical tools to simulate the ethanol production and electricity generation. Furthermore, the process integration and different uses for the excess bagasse were studied with various pretreatment methods aiming the optimizing and ranking of routes. The results indicated optimal settings that allowed the ranking in terms of the environmental exergy indicator \"renewability\" of the production processes for analyzed routes. In this way, the optimized conventional route presented the maximum exergy efficiency of the processes, therefore the lowest exergetic cost average of the evaluated platforms. While the biochemical route was the system that promoted an increase of 28.58 % and 82.87% in the ethanol production, when compared to Case 1 and Case 3, respectively. In addition, the thermochemical route presented the configuration with the highest power generation rate exceeding (214.98 kWh/TC). Concerning, the environmental impact results, it was found that the most sustainable configuration was the biochemical platform, which presented the lowest overall CO2 emissions rates (131.45 gCO2/MJ products). (AU)

• FAPESP's process: 12/23049-2 - EXERGY AND ENVIRONMENTAL RANKING OF BIOETHANOL PRODUCTION ROUTES
• Grantee: Pablo Andrés Silva Ortiz
• Support Opportunities: Scholarships in Brazil - Doctorate