Banca de QUALIFICAÇÃO: GEORGE TADEU DIAS

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : GEORGE TADEU DIAS
DATA : 09/09/2026
TIME: 14:00
LOCAL: DCTEF sala 3.08
TITLE:

Comparative thermodynamic analysis of ethanol and gasoline: first and second law analyses of combustion, simplified performance model, and contribution to the SDGS.

KEY WORDS:

bioethanol, ethanol, gasoline, exergy, compression ratio, decarbonization.

PAGES: 17
BIG AREA: Engenharias
AREA: Engenharia Mecânica
SUMMARY:

The transition to low-carbon energy matrices aligns with the UN Sustainable Development Goals (SDGs 7, 9, 12, and 13), demanding accessible tools for biofuel assessment. This paper presents a comparative thermodynamic analysis between bioethanol (C₂H₅OH) and Brazilian pure gasoline (represented by C₈H₁₄.₉₆) and introduces a simplified thermodynamic model for comparing pure gasoline, regular Brazilian gasoline (E30), anhydrous bioethanol, and hydrous ethanol fuel, filling the gap for low-computational-cost methods to estimate efficiency in Otto cycle engines. The model is based on polytropic compression, evaporative cooling effects, and available chemical energy, integrating First and Second Law of Thermodynamics analyses applied to combustion. The results demonstrate that although ethanol has lower energy density (LHV of 26.43 MJ/kg versus 43.74 MJ/kg for pure gasoline), its higher knock resistance allows the use of higher compression ratios than those used in gasoline engines, resulting in efficiency and power gains of up to 25% for the same displacement in optimized engines. Life cycle analysis shows that ethanol has a negative carbon status, removing more CO₂ from the atmosphere than it emits, with useful energy per kg of CO₂ emitted being 4% higher than that of gasoline. Exergy analysis reveals that although the percentage of exergy destruction is slightly lower for gasoline (30% vs. 33%), the absolute destruction per kmol significantly higher for gasoline (1,486 MJ/kmol) than for ethanol (435 MJ/kmol). The model was calibrated with data from the most produced 1.0L engines in Brazil, showing consistency with actual market values. The computational code developed in Octave allows the reproduction of calculations without the need for proprietary software licenses.

 

BANKING MEMBERS:
Interno - 1755509 - FELIPE SOTO PAU
Interno - 2152276 - GUSTAVO RODRIGUES DE SOUZA
Externo ao Programa - 435055 - JOSE ANTONIO DA SILVA - UFSJ