Banca de DEFESA: MARCELA MAGALHÃES MARCELINO

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : MARCELA MAGALHÃES MARCELINO
DATE: 05/04/2024
TIME: 08:00
LOCAL: Sala de videoconferência RNP_UFBAS_PEI
TITLE:

GASIFICATION OF BAIA COCONUT ENDOCARP USING SUPERCRITICAL WATER AND NICKEL-BASED NANOCATALYST.

KEY WORDS:

coconut husk; supercritical water gasification; nanocatalysts; nickel.

PAGES: 123
BIG AREA: Engenharias
AREA: Engenharia de Produção
SUMMARY:

The utilisation of residual solid biomass for energy generation and intermediate compounds has sparked industry interest due to societal and governmental pressures regarding global climate issues. In Brazil, coconut husk, especially the endocarp, is an abundant residual biomass with significant potential for energy utilization. Among various thermochemical conversion routes for biomass, the technology of Supercritical Water Gasification (SCWG) stands out, converting biomass into synthesis gas with higher H2 concentration and low tar and coal content. This technology is relatively understudied in the literature. To enhance SCWG efficiency, an alternative is the impregnation of biomass with nanocatalysts. This thesis investigated the use of a nanostructured nickel-based catalyst impregnated into coconut endocarp for its gasification using supercritical water (T > 375°C and P > 22.1 MPa) as a reactive medium. The Box-Behnken experimental design, following the Response Surface Methodology (RSM), was chosen for the development of SCWG tests on coconut husk. The effects of the following variables on the efficiency and yield of the gasification process were evaluated: temperature (400, 450, and 500°C), residence time (20, 40, and 60 minutes), and feed concentration (20, 25, and 30%). Additionally, characteristics of gas, liquid, and solid products were also analysed. The impact of the presence and concentration of the catalyst on the efficiency and yield of supercritical water gasification of biomass was particularly assessed. From the characterization of biomass impregnated with nickel salt solutions at concentrations of 1 Molar (1M) and 2 Molar (2M), it was observed that nickel was present at 1.6 and 5.6 wt% , with particle sizes of 7.2 and 13.5 nm. Through the application of RSM, it was observed that temperature had the greatest effect on the composition of the gas product. The higher nickel concentration in the 2M sample resulted in higher H2 content (15.2 mol%), process efficiencies, and the transition of nickel ions to the form of nanoparticles (Ni(0)). Additionally, the chemical composition of the liquid product demonstrated the significant ability of nickel to promote lignin decomposition into phenol, facilitating the hydrogenation reaction of phenol and subsequent gas production. This thesis aimed to generate new knowledge in the promising field of the SCWG process by impregnating a nickel nanocatalyst into coconut biomass, aiming to increase the efficiency of its conversion into synthesis gas, with a focus on obtaining a higher concentration of renewable hydrogen.

COMMITTEE MEMBERS:
Interno - 286723 - EDNILDO ANDRADE TORRES
Externo à Instituição - ELECTO EDUARDO SILVA LORA - UNIFEI - UNI
Externo à Instituição - EMANUEL NEGRÃO MACEDO - UFPA
Externo à Instituição - FERNANDO LUIZ PELLEGRINI PESSOA - Senai
Externo ao Programa - 2362069 - RAILDO ALVES FIUZA JUNIOR - nullPresidente - 1523793 - SILVIO ALEXANDRE BEISL VIEIRA DE MELO