Banca de DEFESA: YURI KAUA RODRIGUES DE OLIVEIRA SILVA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : YURI KAUA RODRIGUES DE OLIVEIRA SILVA
DATE: 08/06/2023
TIME: 09:00
LOCAL: Auditório do NUPPRAR
TITLE:

Evaluation of Ni/Al₂O₃ Catalysts Modified with B₂O₃ and Cobalt in the Dry Methane Reforming Reaction.

KEY WORDS:

Methane dry reforming; syngas; hydrogen; catalytic promoter; Ni/Al₂O₃

PAGES: 100
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Físico-Química
SPECIALTY: Cinética Química e Catálise
SUMMARY:

Dry reforming of methane (DRM) is a synthetic route for the production of syngas from a binary gas mixture with greenhouse gases (CH₄ and CO₂). This reaction has garnered significant academic interest due to it’s similarity to the production of synthesis gas from biogas reforming, which shares the same componentes, but with varying ratios of CH₄ and CO₂. The main challenge regarding this topic is the rapid deactivation of catalysts, primarily caused by the high production of inorganic carbon (coke) that encapsulates the active phase particles and hinders long-term conversion. In this regard, seven catalysts were planned, prepared, and evaluated following the established mixture design. These included one nickel (Ni) catalyst used as a standard, two boron trioxide (B₂O₃) promoted Ni catalysts, two bimetallic Ni-Cobalt (Co) catalysts, and two B₂O₃-promoted bimetallic catalysts, all supported on gamma-alumina. The support was synthesized using the microwave-assisted combustion method, employing urea as the fuel. The metals and non-metallic promoter were introduced by co-impregnation with insipid wetness, followed for a subsequent heat treatment at 550 °C for three hours. The catalysts were structurally characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV-Vis), field-emission scanning electron microscopy (FE-SEM), and energy-dispersive X-ray spectroscopy (EDS). Catalyst activation was carried out at 700 °C for one hour under a hydrogen (H₂) flow. Catalytic tests were conducted in a fixed-bed catalytic unit coupled with a gas chromatograph. The materials were tested for 12 hours at a space velocity of 96 L·g^-1·h^-1. The formed carbon was characterized by XRD and Raman spectroscopy, which revealed lower formation of crystalline carbon with a disorder degree of 1.29 for the sample with a higher amount of B₂O₃. The carbon content was quantified using thermogravimetric analysis (TGA), demonstrating that the insertion of B₂O₃ reduced the carbon amount by up to 57.7%. The results indicate high stability, improved activity, and reduced coke deposition for the catalysts containing all three components. Statistical modeling shows a strong correlation between the varied components and catalyst performance, with boron significantly reducing coke formation and cobalt providing activity and stability in terms of sintering. The proposed special cubic predictive model demonstrates high statistical significance, as evidenced by the Fisher test with an Fcalc/Ftab ratio of 41.12.

COMMITTEE MEMBERS:
Presidente - 349770 - DULCE MARIA DE ARAUJO MELO
Externo ao Programa - 3304576 - RODOLFO LUIZ BEZERRA DE ARAÚJO MEDEIROS - nullInterno - 2087667 - TIAGO PINHEIRO BRAGA
Externo à Instituição - VÍTOR RODRIGO DE MELO E MELO - IFRN