Catalytic steam reforming of acetic acid as a model compound of bio-oil

doi:10.1016/j.apcatb.2014.05.024

Applied Catalysis B: Environmental

Volumes 160–161, November 2014, Pages 188-199

https://doi.org/10.1016/j.apcatb.2014.05.024 Get rights and content

Highlights

•
Steam reforming of acetic acid: compound model of bio-oil.
•
The addition of Mg improves the resistance to coke formation.
•
Sintering process of Ni.

Abstract

The effect of Ni catalysts promoted with Mg on catalytic activity and carbon deposition was investigated in acetic acid steam reforming. Acetic acid was chosen as representative compound for the steam reforming of bio-oil derived from biomass pyrolysis. In this study, nickel catalysts modified with Mg have been prepared by sequential impregnation method with 15 wt.% Ni and variable loadings of Mg (1–10 wt.%). The samples were characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD), X-ray absorption fine structure (XAFS), high resolution transmission electron microscopy (HRTEM), specific surface area (BET) and temperature programmed reduction (TPR-H₂). Steam reforming of acetic acid was conducted in a fixed bed reactor at a temperature of 500 °C and 600 °C. Under reactive conditions, the 15Ni5Mg/Al catalyst proved to be superior to the other catalysts at 600 °C at which it presented an effluent gaseous mixture with the highest H₂ selectivity and reasonable low coke formation.

Graphical abstract

Introduction

The depletion and environmental pollution from fossil fuels necessitate new energy resource development [1]. Hydrogen is recognized as the most promising alternative to fossil fuels for the future because of its cleanness, recyclability and high energy density [2], [3]. Hydrogen can be produced from a variety of sources such as fossil fuels, nuclear energy, water and biomass [4]. Currently, hydrogen is produced mainly from fossil fuels; roughly 96% of hydrogen is produced by steam reforming natural gas and oil fractions [5], [6]. The hydrogen production from fossil fuels presents some disadvantages such as additional consumption of fossil fuel as energy source and release of large amounts of CO₂ into the atmosphere [7]. In addition, the production of hydrogen from water using non-fossil primary energy sources (atomic, solar, geothermal and others) is still disadvantageous economically [8]. This is expected to result in increased usage of alternative biomass energy. In general terms, production of H₂ from biomass wastes can reduce waste disposal problems and substrate costs, thus becoming attractive. Moreover, it does not contribute to global warming since carbon dioxide from the atmosphere is recycled [9], [10].

Hydrogen can be produced from biomass via thermochemical processes, such as flash pyrolysis, which produces mainly liquids (bio-oils), and then the bio-oils can be converted to hydrogen by catalytic steam reforming [11], [12]. Steam reforming of bio-oil produced from fast pyrolysis of biomass has been described by many authors as one of the most promising and economical methods for hydrogen production [13], [14], [15]. Bio-oil is a complex mixture of organic compounds like acids, ketones, esters, alcohols, phenols and guaiacols, and its steam reforming is characterized with many difficulties; the most important is coke accumulation over the catalytic surface [16], [17]. Therefore, designing efficient catalyst requires the use of model oxygenated components for preliminary tests. Acetic acid (HAc), which is soluble in water, is chosen as a model compound because it is one of the most representative constituents of bio-oil [18]. Thermodynamic calculations have proven and accounted for the feasibility of acetic acid steam reforming [19]. Stoichiometrically, steam reforming of HAc can be represented as follows (Eq. (1)):CH₃COOH + 2H₂O → 2CO₂ + 4H₂ ΔH°_298 K = 32.21 kcal/mol

Nickel catalysts are widely used as low-cost non-noble metal catalysts in industry for a number of chemical reaction processes. This metal is commonly employed as the active phase to conduct steam reforming of organic compounds such as methane, ethanol and glycerol, due to the high C–C bond breaking activity [20], [21], [22], [23]. Moreover, the nature of the support strongly influences the catalytic performance of supported Ni catalysts destined for steam reforming, as it affects dispersion and stability of the metal as well as may participate in the reaction [24]. Among oxide supports, alumina-based supports are commonly used for steam reforming due to their chemical and physical properties, since they have good mechanical strength and thermal stability, moreover it is possible to control their textural properties [25], [26]. However, the main problem for most of the Ni catalysts supported on alumina is the high deactivation rate related to the formation of coke deposits. The deactivation can occur by covering the active phase due to encapsulating carbon and also by filamentous carbon formation [27], [28]. Thus, basic additives or promoters produce highly dispersed Ni⁰ species, and consequently, can drastically enhance the resistance to carbon deposition over Ni catalysts. Addition of alkaline earth oxides (MgO, CaO) is widely used in reforming formulations to neutralize acidity of Al₂O₃ [29]. These basic additives, besides acting as a poison for the acid sites on alumina, also favor H₂O adsorption and the OH mobility on the surface, accelerating the carbon oxidation and reducing the coke deposition [23].

In order to improve the stability of the nickel catalysts in steam reforming of acetic acid, we prepared and characterized nickel catalysts supported on γ-Al₂O₃ modified by MgO used as promoter; therefore, the total amount of Mg in the nickel catalyst range from 1 to 10 wt.%. The Ni loading was fixed at 15 wt.% in all cases. γ-Al₂O₃ was used as support to obtain Ni catalysts with high specific surface area. The Ni-MgO/γ-Al₂O₃ catalysts were prepared by sequential impregnation method and tested in steam reforming of acetic acid at 500 and 600 °C.

Section snippets

Catalyst preparation

Ni catalysts supported on (MgO)-modified γ-Al₂O₃ were prepared by the sequential impregnation method. The γ-Al₂O₃ powder (200 m2 g⁻¹; V_pore = 0.60 cm³ g⁻¹; Alfa Aesar) was initially calcined under air at 500 °C for 2 h in a muffle furnace in order to remove organic impurities. γ-Al₂O₃ was first impregnated with a solution of Mg(NO₃)₂·6H₂O (Alfa Aesar) with loadings of 1, 5 and 10 wt.% of Mg, under stirring at 70 °C followed by drying overnight in air at 110 °C. The final samples (1%Mg/γ-Al₂O₃, 5%Mg/γ-Al₂O

XRF analysis

The results of X-ray fluorescence showed that the contents were very close to the nominal composition (Table 1), indicating that there was no loss of Ni and Mg by the sequential impregnation method.

XRD analysis

The XRD diffraction patterns for calcined and reduced catalysts are shown in Fig. 1, Fig. 2 and their textural properties in Table 1. The typical diffraction peaks of γ-Al₂O₃ support at 2θ = 36.9°, 46.8° and 66.7° (JCPDS 86-1410) virtually coincided with those of the NiAl₂O₄ and MgAl₂O₄ spinel-like

Conclusion

Through analysis of X-ray diffractometry it was observed that with increased Mg load in the catalysts, the main diffraction peaks of γ-Al₂O₃ shift to a small angle, due to the formation of the MgAl₂O₄ phase. This effect is more evident in the 15Ni5Mg/Al and 15Ni10Mg/Al catalysts. The EXAFS analyses corroborate the XRD findings. The local chemical environment of Ni after calcination may be described as Ni aluminate phase. It was observed that the addition of Mg in the calcined catalysts does not

Acknowledgements

The authors thank the Brazilian National Council for Scientific Development (CNPq) and the Brazilian Synchrotron Light Laboratory (LNLS) in Campinas, Brazil, for the XAS analysis.

References (86)

Y.H.P. Zhang
Int. J. Hydrogen Energy
(2010)
J. Brouwer
Curr. Appl. Phys.
(2010)
B. McLellan et al.
Int. J. Hydrogen Energy
(2005)
R.J. Farrauto
Appl. Catal. B
(2005)
R. Shinnar
Technol. Soc.
(2003)
R. Chandra et al.
Renew. Sust. Energ. Rev.
(2012)
A.V. Bridgwater
Biomass Bioenerg.
(2012)
L. Garcia et al.
Appl. Catal. A
(2000)
T. Chen et al.
Bioresour. Technol.
(2011)
J.A. Medrano et al.
Energy
(2011)

S. Czernik et al.

Catal. Today

(2007)

P.G.M. Assaf et al.

Catal. Today

(2013)

F. Bimbela et al.

J. Anal. Appl. Pyrolysis

(2007)

A.C. Basagiannis et al.

Appl. Catal. B

(2008)

J.A.Z. Pieterse et al.

Catal. Today

(2010)

S.Q. Chen et al.

Int. J. Hydrogen Energy

(2009)

M.C. Sánchez-Sánchez et al.

Int. J. Hydrogen Energy

(2007)

V.R. Choudhary et al.

J. Catal.

(1997)

D.S. Maciver et al.

J. Catal.

(1963)

J.M. Bermúdez et al.

Fuel

(2012)

D. Chen et al.

Chem. Eng. Sci.

(2001)

A.J. Vizcaíno et al.

Int. J. Hydrogen Energy

(2012)

J. Guo et al.

Appl. Catal. A

(2004)

B. Vos et al.

J. Catal.

(2001)

P. Kim et al.

Appl. Catal. A

(2004)

E.G. Derouane et al.

Stud. Surf. Sci. Catal.

(1993)

L. Zhang et al.

Fuel

(2009)

R.A. Couttenye et al.

J. Catal.

(2005)

A.L. Bonivardi et al.

J. Catal.

(1992)

Y.J.O. Asencios et al.

Appl. Catal. B

(2013)

L.S. Carvalho et al.

Catal. Today

(2009)

Y. Zhang et al.

Fuel Process. Technol.

(2011)

K.Y. Koo et al.

Int. J. Hydrogen Energy

(2008)

T. Shishido et al.

Appl. Catal. A

(2002)

J.T. Richardson et al.

Appl. Catal. A

(1996)

W. Chu et al.

Appl. Catal. A Gen.

(2002)

F. Basile et al.

J. Catal.

(1998)

M. Serra et al.

Solid State Ionics

(2000)

D.G. Rethwisch et al.

Appl. Catal. A

(1986)

S.M. Lima et al.

Appl. Catal. A

(2006)

J.R. Rostrup-Nielsen

Catal. Today

(2002)

D.L. Stern et al.

Catal. Today

(2000)

T. Davidian et al.

Appl. Catal. A

(2008)

Cited by (92)

Y<inf>2</inf>Ti<inf>2</inf>O<inf>7</inf> pyrochlore supported nickel-based catalysts for hydrogen production by auto-thermal reforming of acetic acid
2024, Materials Science and Engineering: B
Hydrogen, as a clean and efficient alternative energy source, can be extracted from acetic acid (HAc), a bio-oil derivative from pyrolysis of renewable biomass. A series of Ni-Y-Ti-O catalysts were synthesized by the Pechini method and applied in auto-thermal reforming (ATR) of HAc for hydrogen production. The N10YT (15 wt% NiO, 75 wt% TiO₂ and 10 wt% YO_1.5) catalyst with Y₂Ti₂O₇ pyrochlore structure presented high activity and stability with a HAc conversion rate at 100% and H₂ yield near 2.62 mol-H₂/mol-HAc, showing application potential for hydrogen production. Characteristics suggested that the improved activity can be attributed to formation of Y₂Ti₂O₇ pyrochlore structure with intrinsic oxygen vacancies and interaction between Ni metal and support by means of (1) promoting of electron transfer from Y³⁺ to Ti⁴⁺ and Ni²⁺ species, (2) facilitating generation of oxygen vacancies and (3) restraining sintering of Ni⁰ and coking.
Upcycling of hazardous plastic waste by CO<inf>2</inf> transformation-enhanced steam reforming over MgO-promoted Ni/C bifunctional catalyst
2024, Chemical Engineering Journal
Disposing hazardous plastic waste (e.g., used masks) poses a challenging issue, as these waste plastics often carry the risk of virus infection. CO₂ transformation-enhanced steam reforming (CTESR) route was developed and newly synthesized dual-support Ni bifunctional catalysts were explored for the upcycling of disposed mask. Among the single-support Ni catalysts, Ni/CaO presented a high H₂ yield (52.18 mmol/g), but it was inferior to Ni/MgO and Ni/C in terms of CO₂ transformation capacity. Importantly, Ni/MgO demonstrated the lowest carbon deposition (∼2.67 wt%) due to the interaction between MgO and NiO, forming a NiO-MgO solid solution. In this sense, dual-support Ni catalysts were prepared to achieve extensive H₂ production and CO₂ reduction. Dual-support Ni/MgO-C was superior to other dual-support catalysts in terms of H₂ selectivity (57.77 vol%), H₂ yield (51.58 mmol/g), CO₂ emission (1.72 mmol/g), and H₂ production efficiency (ƞ: 0.74 g CO₂/g H₂). Moreover, it presented a remarkable synergistic effect on H₂ yield and production efficiency, with an enhancement of 117.27 % and 32.58 %, respectively. The super catalytic performance was attributed to the unique properties of Ni/MgO-C, high dispersion of Ni/NiO active core, and proper interaction of Ni/NiO with the dual supports. In addition, MgO-promoted Ni/C catalysts with multiple MgO proportions were examined. Ni/MgO₅-C₅ was identified as the optimal bifunctional catalyst for H₂-rich syngas production and CO₂ elimination. Overall, this study established a highly effective and promising route by using dual-support Ni catalysts for upcycling hazardous plastic waste into H₂-rich syngas while suppressing CO₂ emission.
Sustainable carbon-based nickel catalysts for the steam reforming of model compounds of pyrolysis liquids
2024, Fuel Processing Technology
Steam reforming of biomass-derived pyrolysis liquids (bio-oil) to produce hydrogen with carbon-based Ni catalysts is gaining attention due to their advantages in terms of cost, sustainability and activity. However, the catalytic activity at long times on stream is compromised by either coke deposition or gasification of the support. To face these drawbacks, two activated carbons have been studied as Ni catalyst support: a microporous carbon of high purity and a mesoporous carbon with phosphorus surface groups. The activity and long-term stability of these catalysts have been studied for the steam reforming of model compounds of bio-oil. The microporous support provided a slightly higher H₂ production and lower contribution of methanation reaction. However, gasification of this support after 20 h led to a decline in the activity, and massive formation of carbon nanotubes and coke. Nevertheless, the resulting material maintained an outstanding stability with high and stable H₂/CO ratio for 50 h. The P-containing catalyst showed a remarkable long-term stability, but lower H₂/CO ratio. Carbon gasification was less significant in this catalyst due to the presence of surface phosphorus groups, and the generation of nickel phosphides, which hampers the growth of pyrolytic carbon and carbon nanotubes, leading to a superior stability.
Sorption enhanced reforming: A potential route to produce pure H<inf>2</inf> with in-situ carbon capture
2023, Fuel
Hydrogen as a fuel is extremely attractive as it offers the highest calorific value when used for combustion. However, industrial processes involving the production of H₂ often involve high operational costs and generally tough conditions. The by-products obtained also play an important factor in determining the yield and purity of the obtained H₂. The main by-products of reforming processes are CO₂ and CH₄. Here, in this study sorption enhanced H₂ production was reviewed upon. Sorption enhanced reforming is becoming increasingly important as it offers a potential solution on a commercial scale to both eliminate CO₂, a major pollutant, as well as increasing the purity of H₂ and the yield as well. Specifically, this review paper focusses on both sorption enhanced chemical looping reforming as well as autothermal reforming processes. In terms of operating conditions, a temperature higher than 873 K was often found to be optimal in terms of increasing H₂ purity. Similarly, a steam to carbon ratio of 5 was found to be optimal. Ni based catalysts often performed well in terms of feed conversion and mixed NiO based oxygen carriers were found to be the most economical. Overwhelmingly, CaO based adsorbents are favoured in order to remove the CO₂ evolved in these processes although Li based adsorbents are also gaining interest. Techno-economic analysis of articles revealed that while a normal reforming process was much cheaper, the autothermal steam reforming process with in-situ CO₂ capture was more economical.
Tuning of active nickel species in MOF-derived nickel catalysts for the control on acetic acid steam reforming and hydrogen production
2023, International Journal of Hydrogen Energy
Acetic acid (AcOH) steam reforming for hydrogen (H₂) generation was investigated using a zero valent nickel complex (Ni-comp) derived from a metal-organic framework precursor supported over aluminum oxide/lanthanum oxide-cerium dioxide (ALC). The effects of Ni loading ratio (10, 15, and 20 wt%) on the catacatalytic activity were investigated in the range of 400 to 650 °C to H₂ generation. The Ni-comp/ALC catalysts exhibited almost complete conversion of AcOH (X_AcOH >98%) to H₂ (X_H2>90%) alongside some impurities (e.g., carbon monoxide, methane, and carbon dioxide). A maximum H₂ yield (91.36% (0.064 mol^-1 g_cat⁻¹ h⁻¹)) was attained at the following conditions: 15 wt% Ni loading, steam to carbon molar ratio of 6.5, weight hourly space velocity of 1.05 h⁻¹, and 600 °C. The 15 wt% Ni catalyst maintained sufficient stability over 40 h reaction time. Accordingly, Ni-comp-ALC interactions were seen to efficiently improve the activity and stability of the catalyst so as to synergistically resist coke deposition and metal sintering through the formation of a large number of free Ni particles and oxygen vacancies.
Effect of Ni-Fe/CaO-Al<inf>2</inf>O<inf>3</inf> catalysts on products distribution in in-situ and ex-situ catalytic pyrolysis of Chinese herb residue
2023, Journal of Analytical and Applied Pyrolysis
It is necessary to investigate the differences between in-situ and ex-situ methods of bimetallic supported catalysts for biomass catalytic pyrolysis. In this paper, the Ni–Fe/CaO–Al₂O₃ catalysts with different Ni/Fe ratios have been synthesized by coprecipitation method, and it was explored that the effect of products distribution about Chinese herb residue(CHR) catalytic pyrolysis by in-situ and ex-situ methods. The results showed that in-situ NiFe-3 group had the highest content of aromatic compounds (59.68%) and the lowest content of aliphatic compounds (17.67%). This was beneficial to the utilization of chemical raw materials extracted from pyrolysis oil. Meanwhile, the CaO in the catalyst effectively reduces the acid content and corrosion of pyrolysis oil. The results showed that higher Ni and CaO content has the synergistic catalytic action in ex-situ catalytic experiments. It could promote water-gas shift reaction, which is conducive to the generation of H₂. In-situ catalysis is mainly used for the upgrading of pyrolysis oil, while ex-situ catalysis is mainly used to promote secondary pyrolysis of pyrolysis products and improve the quality of pyrolysis oil. This work provides reference for the difference and high value utilization of biomass pyrolysis by different catalytic methods.

View all citing articles on Scopus

View full text

Catalytic steam reforming of acetic acid as a model compound of bio-oil

Highlights

Abstract

Graphical abstract

Introduction

Section snippets

Catalyst preparation

XRF analysis

XRD analysis

Conclusion

Acknowledgements

Int. J. Hydrogen Energy

Curr. Appl. Phys.

Int. J. Hydrogen Energy

Appl. Catal. B

Technol. Soc.

Renew. Sust. Energ. Rev.

Biomass Bioenerg.

Appl. Catal. A

Bioresour. Technol.

Energy

Catal. Today

Catal. Today

J. Anal. Appl. Pyrolysis

Appl. Catal. B

Catal. Today

Int. J. Hydrogen Energy

Int. J. Hydrogen Energy

J. Catal.

J. Catal.

Fuel

Chem. Eng. Sci.

Int. J. Hydrogen Energy

Appl. Catal. A

J. Catal.

Appl. Catal. A

Stud. Surf. Sci. Catal.

Fuel

J. Catal.

J. Catal.

Appl. Catal. B

Catal. Today

Fuel Process. Technol.

Int. J. Hydrogen Energy

Appl. Catal. A

Appl. Catal. A

Appl. Catal. A Gen.

J. Catal.

Solid State Ionics

Appl. Catal. A

Appl. Catal. A

Catal. Today

Catal. Today

Appl. Catal. A