Avaliação de impactos ambientais de rotas termoquímicas para aproveitamento integral da biomassa na biorrefinaria de cana-de-açúcar

Author(s)

Ricardo Justino da Silva

• Document type: Master's Dissertation
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Engenharia Química
• Defense date: 2015-02-20

Examining board members

Rubens Maciel Filho; Mylene Cristina Alves Ferreira Rezende; Edgardo Olivares Gómez

• Advisor: Otavio Cavalett; Rubens Maciel Filho

Abstract

Biorefineries have been considered an extremely important alternative to sustainable development and for developing of a `green economy¿ based on local and renewable resources. Biomass is a renewable resource with the potential to reduce dependence on fossil resources and a viable alternative able to replace the main fossil fuels (coal, oil and natural gas). In the case of Brazil, the sugarcane biorefineries take up a prominent position in this scenario, with the production of energy (thermal and electrical), sugar and fuel ethanol with potentials surplus biomass for bio-based products and/or bioenergy production. The biomass of sugarcane can be converted into various bio-based products by chemical, biochemical and thermochemical routes. In this sense, this Master¿s thesis contributes with the assessment of environmental impacts (cradle-to-gate system boundary) of the production of thermal energy, electricity, liquid biofuels and chemicals via thermochemical conversion routes of biomass at an optimized first generation sugarcane biorefinery with annexed ethanol distillery (two million tonnes of processed cane on season) from the integral use of the available lignocellulosic biomass. Thermochemical routes to biomass conversion evaluated are: Cogeneration systems (Rankine cycle) for heat and power production (CHP) using condensing-extraction steam turbine (CEST) system or back-pressure extraction steam turbine (BPEST) system; biomass integrated direct gasification with internal combustion engine in combined cycle (BIG-ICE/CC) system; biomass integrated direct gasification with gas turbine in combined cycle (BIG-GT/CC) system; biomass to methanol production by biomass integrated direct gasification and low-pressure methanol synthesis process (Biomass-to-Methanol); biomass to mixed alcohol production by biomass integrated direct gasification and mixed alcohol synthesis process (Biomass-to-Mixed alcohol). Scenarios with different energy integration possibilities (thermal and electrical) between technologies were evaluated (keeping/not keeping the traditional CHP/BPEST system), well as the possibility/necessity of an upstream co-capture of CO2/H2S from the synthesis gas. Environmental impacts assessment is based on the Life Cycle Assessment (LCA) methodology (ISO14040:2006 and ISO14044:2006) under the scope of the Virtual Sugarcane Biorefinery (VSB) (CTBE, Brazil) computational simulation platform and performed using the World midpoint ReCiPe model in SimaPro®7.3.3 (PRé Consultants, Netherlands) software with an economic allocation approach for evaluate the life cycle inventory (LCI) obtained from CanaSoft (CTBE, Brazil) spreadsheet models and mass and energy balances obtained from Aspen Plus®v.8.4 (AspenTech, USA) simulation platform. The environmental impacts indicators obtained for the main bio-based products in general show advantages over the corresponding products derived from fossil resources (Brazil case) in terms of: climate change; ozone depletion; ionizing radiation; marine ecotoxicity; natural land transformation; urban land occupation; mineral/metal depletion; fossil depletion; and show disadvantages in terms of: agricultural land occupation; particulate matter formation; terrestrial acidification; terrestrial ecotoxicity; photochemical oxidant formation; freshwater eutrophication; freshwater ecotoxicity; marine eutrophication; human toxicity; and water depletion (AU)

• FAPESP's process: 12/23533-1 - Environmental impact assessment of thermochemical routes for integral use of sugarcane biomass
• Grantee: Ricardo Justino da Silva
• Support Opportunities: Scholarships in Brazil - Master