Dry reforming of methane over nickel-tantalum supported on fibrous ZSM-5 catalyst for production of synthesis gas

Dry reforming of methane (DRM) is an environmentally benign process for production of synthesis gas carbon monoxide (CO) and hydrogen (H2) with low H2:CO ratio by utilization of carbon dioxide (CO2) and methane (CH4) as feed gas. The large-scale production of syngas via DRM is still in its infancy d...

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Main Author:	Hambali, Hambali Umar
Format:	Thesis
Language:	English
Published:	2020
Subjects:	TP Chemical technology
Online Access:	http://eprints.utm.my/id/eprint/102184/1/HambaliUmarHambaliPSChE2020.pdf.pdf
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spelling	my-utm-ep.1021842023-08-13T06:05:01Z Dry reforming of methane over nickel-tantalum supported on fibrous ZSM-5 catalyst for production of synthesis gas 2020 Hambali, Hambali Umar TP Chemical technology Dry reforming of methane (DRM) is an environmentally benign process for production of synthesis gas carbon monoxide (CO) and hydrogen (H2) with low H2:CO ratio by utilization of carbon dioxide (CO2) and methane (CH4) as feed gas. The large-scale production of syngas via DRM is still in its infancy due to operational constraints exhibited by the several catalysts involved. In this study, microemulsion engineered fibrous ZSM-5 (FZSM-5) support was selected as the support material due to its extended surface area and stabilization of metal particles. In addition, nickel (Ni) loaded on FZSM-5 was prepared by double solvent, physical mixing and wetness impregnation methods. Furthermore, magnesium (Mg), calcium (Ca), tantalum (Ta) and gallium (Ga) promoters were added to Ni/FZSM-5 catalyst using wetness impregnation method. The catalysts were characterized using X-ray diffraction, nitrogen adsorption-desorption isotherm, transmission electron microscope, field-emission scanning electron microscope, Fourier-transform infrared spectrometer, IR-lutidine chemisorption, temperature-programmed desorption with ammonia and CO2, temperature-programmed reduction with H2, energy-dispersive X-ray, X-ray photoelectron spectrometer, Raman spectrometer, and thermogravimetric analysis. The effects of active metals, Ni-loading methods, support morphology, promoters, Ni-Ta ratio towards the activity, selectivity and stability of the Ni based catalysts were examined in DRM over a temperature range of 500–800 oC and atmospheric pressure. Results revealed that Ni species are highly active for dissociation of the reactants. Ni/FZSM-5 produced superior performance than conventional ZSM-5 supported Ni catalyst. High basicity, surface area and mesoporosity were responsible for the outstanding performance of FZSM-5 supported catalyst. The wetness impregnation catalyst produced superior performance, which was correlated to microscopic dispersion and low surface acidity. The activity of the bimetallic catalysts was in the order: Ni-Ga/FZSM-5 (CH4= 50.1 %, CO2= 58.8 %) < Ni-Ca/FZSM-5 (CH4= 82.9 %, CO2= 82.7 %) < Ni-Mg/FZSM-5 (CH4= 86.7 % ,CO2= 92.3 %) < Ni-Ta/FZSM-5 (CH4= 91 % ,CO2= 97.4 %). The side reaction (methane cracking, Boudouard and RWGS) test results indicated that Ni catalyst had high inclination towards methane cracking reaction. The presence of small Ta cations in Ni catalyst was enough to suppress the driving force for agglomeration and coke formation. The optimum CH4 conversion predicted from the response surface analysis was 96.6 % at reaction temperature of 784.15 °C, CO2:CH4 feed ratio of 2.52, and GHSV of 33,760 mL g-1 h-1. Experiment carried out with these optimum parameters gave 95.8 % CH4 conversion with error of 0.8 %. The strong catalytic stability of Ni-Ta/FZSM-5 was due to the small-size and immobilized Ni sites, enhanced reducibility and interaction of catalyst components. This study highlighted the contribution of fibrous structured ZSM-5 support and Ni-Ta catalyst in the quest for potent catalyst development for industrial production of syngas via DRM. 2020 Thesis http://eprints.utm.my/id/eprint/102184/ http://eprints.utm.my/id/eprint/102184/1/HambaliUmarHambaliPSChE2020.pdf.pdf application/pdf en public http://dms.library.utm.my:8080/vital/access/manager/Repository/vital:149209 phd doctoral Universiti Teknologi Malaysia Faculty of Engineering - School of Chemical & Energy Engineering
institution	Universiti Teknologi Malaysia
collection	UTM Institutional Repository
language	English
topic	TP Chemical technology
spellingShingle	TP Chemical technology Hambali, Hambali Umar Dry reforming of methane over nickel-tantalum supported on fibrous ZSM-5 catalyst for production of synthesis gas
description	Dry reforming of methane (DRM) is an environmentally benign process for production of synthesis gas carbon monoxide (CO) and hydrogen (H2) with low H2:CO ratio by utilization of carbon dioxide (CO2) and methane (CH4) as feed gas. The large-scale production of syngas via DRM is still in its infancy due to operational constraints exhibited by the several catalysts involved. In this study, microemulsion engineered fibrous ZSM-5 (FZSM-5) support was selected as the support material due to its extended surface area and stabilization of metal particles. In addition, nickel (Ni) loaded on FZSM-5 was prepared by double solvent, physical mixing and wetness impregnation methods. Furthermore, magnesium (Mg), calcium (Ca), tantalum (Ta) and gallium (Ga) promoters were added to Ni/FZSM-5 catalyst using wetness impregnation method. The catalysts were characterized using X-ray diffraction, nitrogen adsorption-desorption isotherm, transmission electron microscope, field-emission scanning electron microscope, Fourier-transform infrared spectrometer, IR-lutidine chemisorption, temperature-programmed desorption with ammonia and CO2, temperature-programmed reduction with H2, energy-dispersive X-ray, X-ray photoelectron spectrometer, Raman spectrometer, and thermogravimetric analysis. The effects of active metals, Ni-loading methods, support morphology, promoters, Ni-Ta ratio towards the activity, selectivity and stability of the Ni based catalysts were examined in DRM over a temperature range of 500–800 oC and atmospheric pressure. Results revealed that Ni species are highly active for dissociation of the reactants. Ni/FZSM-5 produced superior performance than conventional ZSM-5 supported Ni catalyst. High basicity, surface area and mesoporosity were responsible for the outstanding performance of FZSM-5 supported catalyst. The wetness impregnation catalyst produced superior performance, which was correlated to microscopic dispersion and low surface acidity. The activity of the bimetallic catalysts was in the order: Ni-Ga/FZSM-5 (CH4= 50.1 %, CO2= 58.8 %) < Ni-Ca/FZSM-5 (CH4= 82.9 %, CO2= 82.7 %) < Ni-Mg/FZSM-5 (CH4= 86.7 % ,CO2= 92.3 %) < Ni-Ta/FZSM-5 (CH4= 91 % ,CO2= 97.4 %). The side reaction (methane cracking, Boudouard and RWGS) test results indicated that Ni catalyst had high inclination towards methane cracking reaction. The presence of small Ta cations in Ni catalyst was enough to suppress the driving force for agglomeration and coke formation. The optimum CH4 conversion predicted from the response surface analysis was 96.6 % at reaction temperature of 784.15 °C, CO2:CH4 feed ratio of 2.52, and GHSV of 33,760 mL g-1 h-1. Experiment carried out with these optimum parameters gave 95.8 % CH4 conversion with error of 0.8 %. The strong catalytic stability of Ni-Ta/FZSM-5 was due to the small-size and immobilized Ni sites, enhanced reducibility and interaction of catalyst components. This study highlighted the contribution of fibrous structured ZSM-5 support and Ni-Ta catalyst in the quest for potent catalyst development for industrial production of syngas via DRM.
format	Thesis
qualification_name	Doctor of Philosophy (PhD.)
qualification_level	Doctorate
author	Hambali, Hambali Umar
author_facet	Hambali, Hambali Umar
author_sort	Hambali, Hambali Umar
title	Dry reforming of methane over nickel-tantalum supported on fibrous ZSM-5 catalyst for production of synthesis gas
title_short	Dry reforming of methane over nickel-tantalum supported on fibrous ZSM-5 catalyst for production of synthesis gas
title_full	Dry reforming of methane over nickel-tantalum supported on fibrous ZSM-5 catalyst for production of synthesis gas
title_fullStr	Dry reforming of methane over nickel-tantalum supported on fibrous ZSM-5 catalyst for production of synthesis gas
title_full_unstemmed	Dry reforming of methane over nickel-tantalum supported on fibrous ZSM-5 catalyst for production of synthesis gas
title_sort	dry reforming of methane over nickel-tantalum supported on fibrous zsm-5 catalyst for production of synthesis gas
granting_institution	Universiti Teknologi Malaysia
granting_department	Faculty of Engineering - School of Chemical & Energy Engineering
publishDate	2020
url	http://eprints.utm.my/id/eprint/102184/1/HambaliUmarHambaliPSChE2020.pdf.pdf
_version_	1776100865921253376

Dry reforming of methane over nickel-tantalum supported on fibrous ZSM-5 catalyst for production of synthesis gas

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