Development of mesoporous nickel catalyst for dry reforming reaction of methane
Thesis Type: Postgraduate
Institution Of The Thesis: Gazi University, Fen Bilimleri Enstitüsü, Turkey
Approval Date: 2023
Thesis Language: Turkish
Student: Sevtap ALP
Supervisor: Nail Yaşyerli
Open Archive Collection: AVESIS Open Access Collection
Abstract:
Dry reforming of methane (MDR) is a process used to convert the two main greenhouse gases, methane (CH4) and carbon dioxide (CO2), into syngas (a mixture of H2 and CO) which is useful for reducing global warming problems. In this process, it is extremely important to develop a catalyst to minimize problems such as carbon accumulation and sulfur poisoning. In the thesis study, it was aimed to investigate the resistance of the addition of boron to the SBA-15 supported nickel catalysts against the coke formation and H2S poisoning of the catalyst in the dry reforming reaction of methane. For this purpose, SBA-15 material was synthesized by hydrothermal method as support material. First of all, SBA-15 supported boron added nickel catalysts were tried to be synthesized in different acidity environments by the one-pot hydrothermal method, but it was observed that nickel did not enter the structure in the washing process. Then, SBA-15 supported, boron-free catalysts containing 1, 2 and 5% boron and 5% nickel by mass were prepared by co-impregnation methods. Activation tests of catalysts prepared using co-impregnation method for the dry reforming reaction of methane in the absence of H2S and in the presence of 50 ppm H2S gas mixture ratio at 750°C, atmospheric pressure (1 atm) and CH4/CO2/(H2S+Ar) gas mixture ratio in the feed 1/1/1 while it was carried out. Various characterization studies (XRD, SEM, N2 adsorption/desorption, DRIFTS, TGA) were carried out in order to determine their structural, physical and chemical properties before and after the reaction. The N2 adsorption desorption results of SBA-15 supported catalysts are compatible with type IV, an indication that the structure is mesoporous. However, with the increase in the amount of boron added to the structure, changes were observed in the N2 adsorption-desorption isotherms. When the DRIFT analyses were examined, it was observed that the boron added to the structure decreased the acidity of the nickel catalyst. When the activation results were evaluated, while the methane conversion at t=1 time was 70 % for the 5Ni@SBA-15 catalyst, it decreased to 10% with the boron added at the rate of 5 % by mass. TGA results show that boron added to the structure reduces carbon deposition for the nickel catalyst. In the catalytic activity tests carried out in the presence of H2S, it was determined that the addition of boron did not improve the H2S resistance of the nickel catalyst.
Anahtar Kelimeler : Biogas, dry reforming of methane, SBA-15, nickel, boron