Effect of Magnesia Addition in Stability of Cobalt Catalysts Supported on Alumina for Hydrogen Generation by Glycerol St
- PDF / 1,598,138 Bytes
- 13 Pages / 595.276 x 790.866 pts Page_size
- 80 Downloads / 163 Views
Effect of Magnesia Addition in Stability of Cobalt Catalysts Supported on Alumina for Hydrogen Generation by Glycerol Steam Reforming João Paulo da S. Q. Menezes1 · Karine R. Duarte1 · Mariana M. V. M. Souza1 Received: 28 June 2020 / Accepted: 20 August 2020 © Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract Cobalt catalysts were prepared by wet impregnation of four distinct supports: alumina, magnesia and two mixed supports of alumina with magnesia (10 and 30 wt%), prepared by wet impregnation of magnesia precursor on alumina. Magnesia addition decreased catalyst acidity and reduced spinel phase formation; however, high magnesia content (30 wt%) decreased catalyst reducibility and cobalt dispersion. The catalysts were evaluated on steam reforming of glycerol for 30 h at 500 °C, GHSV of 200,000 h−1 and a glycerol solution 20% v/v in the feed. All catalysts, except the catalyst supported on pure magnesia, presented deactivation during reaction time, because of coke formation and reoxidation of metallic cobalt phase, mainly for the catalyst supported on 30%MgO–Al2O3. The catalyst supported on Al2O3 exhibited the highest mean conversion to gas (42.4%) and hydrogen yield (31.2%) during time on stream. However, the catalyst supported on 10%MgO–Al 2O3 presented higher stability in terms of glycerol conversion to gas and hydrogen yield, associated with preferential formation of filamentous coke instead of amorphous coke.
* Mariana M. V. M. Souza [email protected] 1
Escola de Química- Universidade Federal Do Rio de Janeiro (UFRJ), Centro de Tecnologia, Bloco E, sala 206, Rio de Janeiro, RJ CEP 21941‑909, Brazil
13
Vol.:(0123456789)
J. P. S. Q. Menezes et al.
Graphic Abstract
Steam Reforming T = 500 °C - GHSV = 200,000 h-1
100
50
20 vol.% HO
OH OH
Glycerol
40
H2 Yield (%)
Conversion (%)
80 60
30
40
2
4
Co
6
8
24
Time (h)
26
Co
Support Support
H2
10 0
0
CO₂₂
20
CoAl Co10MgAl Co30MgAl CoMg
20 0
CH₄₄
CO
CoAl Co10MgAl Co30MgAl CoMg
Co
28
30
0
2
Deacvaon
Al₂O₃ 10% MgO-Al₂O₃ 30% MgO-Al₂O₃ MgO
4
6
8 24
Time (h)
Co
26
28
Co3O4 Co₃O
Support
30
Liquid byproducts
O
Coke deposits
Acrolein
Dehydraon
OH O Acetol
Propanoic acid
Keywords Glycerol · Reforming · Hydrogen · Cobalt · Magnesia
1 Introduction The extensive use of fossil fuels along the decades is mainly responsible for the release of pollutant gases, such as carbon dioxide, methane, SOx and NOx. These gases in excess may cause damage to nature and affect the human health. Moreover, fossil fuels are non-renewable resources. Thus, they do not meet the requirements for the sustainability. In this context, the development of new processes based on cleaner and renewable resources, as biomass, would reduce the dependency on fossil fuels and contribute to a greener and more sustainable energy production [1]. Recently, an increase in research of different renewable resources for energy production has been noticed in the literature. In this scenario, oils and fats originated from pl
Data Loading...
