Banca de DEFESA: ANDREZA DUARTE MEMELLI MENDONÇA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : ANDREZA DUARTE MEMELLI MENDONÇA
DATE: 23/05/2022
TIME: 08:00
LOCAL: Ambiente virtual, GoogleMeet
TITLE:

Evaluation and optimization of the experimental process of biodiesel synthesis by alkaline metanolysis at 25.0 °C

KEY WORDS:

biodiesel, soybean oil, inverted procedure

PAGES: 119
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Química Analítica
SPECIALTY: Métodos Óticos de Análise
SUMMARY:

The possible depletion of fossil fuels, the increase in CO2 emissions, and the growing energy demand have aroused interest in alternative sources of green energy. In this sense, biodiesel, a biofuel from renewable sources, has been used as an alternative to replace petroleum diesel. Research involving its synthesis is constantly advancing with the aim of optimizing more and more the process variables. Most of the studies employ a conventional synthesis methodology where the reactants are mixed with the direct addition of the catalyst/alcohol solution over the oil, under constant stirring and heating. This work sought to investigate and optimize an alternative, unprecedented proposal for the synthesis of methyl biodiesel, in which the gradual addition of soybean oil is carried out over the catalyst/methanol solution (inverted procedure), changing the sequence and speed of addition of the reagents. compared to the conventional methodology. The experiments were promoted at 25.0 °C for a lower energy consumption. The study was conducted using a 24 factorial design aiming at the optimization of the following reaction conditions: type of catalyst (NaOH and NaOCH3); synthesis time (40 and 60 minutes); stirring speed (400 and 600 rpm); and oil addition time in the catalyst/methanol mixture in relation to reaction time (percentage relative time, tR) (60 and 80%). After planning, studies were carried out to achieve greater conversions based on the evaluation of the effect of stirring speed (200, 300, 400, 500 and 600 rpm), tR (20, 40, 60 and 80%) and synthesis in two successive steps of transesterification, additionally, a comparison was made between the conventional and proposed synthesis procedures. The planning indicated that the tR and the time of synthesis were the main factors of influence in the conversion for the studied system. Conversions around 86% were obtained by applying tR of 60% for 60 minutes and 400 rpm with the two catalysts used (NaOH and NaOCH3). The post-planning study demonstrated that the strategy of slow addition of oil over the catalyst/alcohol solution achieved higher conversion averages at room temperature and low stirring speeds (up to 300 rpm) compared to the conventional method. The best condition used was performing the biodiesel synthesis in two transesterification steps of 60 minutes, tR of 20%, stirring speed of 300 rpm and NaOH as catalyst, resulting in a conversion of 96.6%. A high conversion of triglycerides was obtained using the proposed experimental procedure under milder conditions and with lower energy consumption when compared to conventional syntheses under heating. This result makes the new experimental procedure attractive for industrial application, considering that minimal changes in the manufacturing process will be necessary, which can even be compensated in the long term by the lower energy demand. The analysis of acidity index, specific mass, kinematic viscosity and ester content indicated the quality of the resulting biodiesel within the standards established by Brazilian legislation.

BANKING MEMBERS:
Presidente - 2626414 - JOSE GERALDO ROCHA JUNIOR
Externa à Instituição - EVA LUCIA CARDOSO SILVEIRA
Externa à Instituição - LILIA BASÍLIO DE CALAND
Externa à Instituição - PRÍSCILA MARQUES DE SIQUEIRA
Externo à Instituição - LUIZ FERNANDO SILVA CALDAS - IFRJ