Preparation of high-dispersion Ni/C catalyst using modified lignite as carbon precursor for catalytic reforming of biomass volatiles

doi:10.1016/j.fuel.2017.04.060

Fuel

Volume 202, 15 August 2017, Pages 345-351

https://doi.org/10.1016/j.fuel.2017.04.060 Get rights and content

Highlights

•
Demineralization caused the pore corrosion and decreased the activity of Ni/C.
•
High Ni loading and well dispersed Ni/C was prepared by acid treatment of lignite.
•
H₂O₂ oxidation can improve the carboxyl group content of raw and modified lignite.
•
Carboxyl group content is a key parameter for Ni/C preparation.
•
Inherent minerals have a good influence on Ni/C for biomass volatile reforming.

Abstract

Lignite is rich in oxygen-containing species (OCSs) and able to load Ni via ion exchange to prepare Ni/C catalyst. However, the OCSs usually exists in the form of organic salts, which can reduce the capacity of Ni ion exchange. In this paper, Shengli lignite (SL) was treated with HCl and HCl/HF to selectively remove the organic salts and insoluble minerals, respectively, and the modified lignite was oxidized by H₂O₂ to further increase the carboxyl content. The treated lignite was used to prepare Ni/C catalyst and the activity for biomass volatile reforming was evaluated. The results show that demineralization (DM) caused the corrosion of pore structure of SL and gave a Ni/C catalyst with a low specific surface area (SSA) of 222.1 m²/g. Oxidation with H₂O₂ further destroyed the structure of DMSL and provided a Ni/C with the lowest SSA of 141.1 m²/g. Acid wash (AW) with HCl resulted in the increase of ion exchange capacity of SL and gave a Ni/C catalyst with larger SSA, higher loading, lower particle size and well dispersion of Ni particle in comparison with SL and DMSL. H₂O₂ treatment of AWSL significantly increased the amount of carboxyl group to 3.8 mmol/g and gave a Ni/C with the largest SSA of 291.1 m²/g, highest Ni loading of 17.3% and smallest Ni crystallite size of 3.4 nm, as well as most active for corncob volatile reforming.

Graphical abstract

Introduction

Lignite has a high ability of spontaneous combustion since the rich in oxygen-containing species (OCSs) [1], [2], [3]. Due to abundance in OCSs, lignite was reported present high ion-exchanging ability with metal, such as Ni, and great dispersion of the Ni within the coal matrix [4], [5].

We previously reported a novel catalyst with dispersed metallic Ni particles in a Ni crystallite size (NCS) of 5.6 nm and a relatively high specific surface area (SSA) by loading Ni on Shenli lignite (SL) char. The catalyst that nickel-loaded on lignite was successfully utilized for volatile reforming in biomass gasification [6]. However, lignite contains a relatively high ash content, which might affect the ion-exchange capacity as well as the catalyst activity. Therefore, modified lignite provides a potential way to value-added utilization of lignite. Minerals in lignite can be divided into the minerals which exist independently (kaolin, montmorillonite, pyrite, calcite and quartz, etc) and inorganic elements associated with the organic matter. The Na, K, Mg and Ca are usually exchanged in carboxylate groups [7], which can affect the Ni loading and dispersity. Lignite has a certain catalytic activity in gasification reactions since the existence of high content of minerals [8], [9], [10]. The catalytic activity of minerals is dependent on their chemical form exists in the coal matrix, as well as the concentration and dispersion. It was proved that the alkali and alkaline earth metals in coal have a certain affect in the reactivity of lignite char [11], [12]. Ca and Mg usually exist in carbonates form and show predominantly organic affinity [7], [13]. To investigate the catalytic activity of minerals in lignite, DM and AW are need before catalyst preparation.

The OCSs, especially carboxylic groups, are able to exchange ions with external molecules and the exchanged ions are highly dispersed around the coal matrix [4]. The oxidation of lignite may play an important role in improving of SSA and microporosity and the amount of ion exchange in catalyst preparation. Potassium permanganate, peroxyacetic acid, sodium hypochlorite, oxygen and hydrogen peroxide were used for increasing OCSs content [14], [15], [16], [17], [18], [19], [20], especially for environmentally friendly oxidant of hydrogen peroxide [21], [22]. The ion exchange capacity of the lignite can be enhanced by oxidation treatment to provide the carboxyl group.

In this study, Ni/C catalysts were prepared by acid washing, demineralizing and oxidizing of lignite to study the effects of minerals and carboxyl groups on the Ni loading, NCS, Ni particle size and SSA of the catalysts. The catalytic activity of the as prepared Ni/C catalysts for cracking tarry materials from biomass pyrolysis was investigated in a two-stage fixed-bed quartz reactor.

Section snippets

Preparation of acid washed, demineralized and oxidized lignite

The demineralized lignite (DMSL) was prepared by acid leaching of SL. About 20 g SL sample was stirred with 5 M HCl for 1 h at 55 °C and filtered, then the filter cake was treated with 11 M HF for 1 h at 55 °C. After filtration, the sample was treated again with another batch of 5 M HCl for 1 h at 55 °C, followed by repeated washing with deionized water (DIW) until neutral and no Cl⁻ can be detected. As reported previously [23], for acid washed lignite (AWSL), 20 g of lignite was treated with 5 M HCl for 2

FTIR analysis

As shown in Fig. 1, there is a transmission band at around 3428 cm⁻¹, which can be attributed to the stretching vibration of single bond OH from residual water. The bands at 2920 and 2850 cm⁻¹ are due to aliphatic CH, CH₂ and CH₃ stretching vibrations. An apparent band appeared at 1710 cm⁻¹, which corresponding to the stretching vibration of C double bond O in carboxyl groups. The relatively strong band of carboxyl groups in OXSL, OXDMSL and OXAWSL are well consistent with the results of the chemical titration (Table S1).

Conclusions

The carbon skeleton of SL can be corroded seriously during DM. The demineralized sample, i.e., DMSL and OXDMSL have relatively low Ni loading and activity for biomass tar reforming in comparison to SL. Acid treatment of SL significantly reduce the content of metal cation associated with the OCSs, increase the carboxyl and hydroxyl amount and further enhance the Ni loading of AWSL via ion exchange. Oxidation with H₂O₂ can further increase the carboxyl amount of raw and treated lignite, and make

Acknowledgements

This work was subsidized by the Fundamental Research Funds for the Central Universities (China University of Mining & Technology, Grant 2015XKQY05), the National Natural Science Foundation of China (Grant 21676292), the Natural Science Foundation of Jiangsu Province (BK20151141), and the Priority Academic Program Development of Jiangsu Higher Education Institutions.

References (37)

X.B. Feng et al.
Organic oxygen transformation during pyrolysis of Baiyinhua lignite
J Anal Appl Pyrol
(2016)
T.L. Liu et al.
In situ upgrading of Shengli lignite pyrolysis vapors over metal-loaded HZSM-5 catalyst
Fuel Process Technol
(2017)
C.A. Eligwe et al.
Adsorption of iron(II) by a Nigerian brown coal
Fuel
(1994)
Y. Wang et al.
Catalytic steam reforming of cellulose-derived compounds using a char-supported iron catalyst
Fuel Process Technol
(2013)
B.S. Wang et al.
Preparation of nickel-loaded on lignite char for catalytic gasification of biomass
Fuel Process Technol
(2015)
E. Pehlivan et al.
Removal of metal ions using lignite in aqueous solution-Low cost biosorbents
Fuel Process Technol
(2007)
L. Wei et al.
Hydrogen production by methane cracking over Xiaolongtan lignite chars: The role of mineral matter
Fuel
(2016)
L. Jiang et al.
Catalytic effects of inherent alkali and alkaline earth metallic species on steam gasification of biomass
Int J Hydrogen Energy
(2015)
K. Matsuoka et al.
Transformation of alkali and alkaline earth metals in low rank coal during gasification
Fuel
(2008)
N. Li et al.
Direct production of high hydrogen syngas by steam gasification of Shengli lignite/chars: Remarkable promotion effect of inherent minerals and pyrolysis temperature
Int J Hydrogen Energ
(2017)

S. Krishnakumar et al.

Trace element concentrations in reef associated sediments of Koswari Island, Gulf of Mannar biosphere reserve, southeast coast of India

Mar Pollut Bull

(2017)

F.J. Liu et al.

Investigation on structural features of Shengli lignite through oxidation under mild conditions

Fuel

(2013)

Y.F. Patrakov et al.

Influence of ozone treatment on change of structural-chemical parameters of coal vitrinites and their reactivity during the thermal liquefaction process

Fuel

(2006)

F.J. Liu et al.

Oxidation of Shengli lignite with aqueous sodium hypochlorite promoted by pretreatment with aqueous hydrogen peroxide

Fuel

(2013)

L. Doskočil et al.

Hydrogen peroxide oxidation of humic acids and lignite

Fuel

(2014)

D. Borah et al.

Oxidation of high sulphur coal. Part 2. Desulphurisation of organic sulphur by hydrogen peroxide in presence of metal ions

Fuel

(2001)

T. Wang et al.

Sulfur transformations during supercritical water oxidation of a Chinese coal

Fuel

(2003)

D. Vamvuka et al.

The effect of mineral matter on the physical and chemical activation of low rank coal and biomass materials

Fuel

(2006)

Cited by (66)

Pretreatment of poplar powder by light bio-oil for preparation of porous carbon materials with excellent electrochemical performance
2024, Diamond and Related Materials
Reasonable pretreatment strategies play a crucial role in enhancing the pore structure and electrochemical performance of porous carbon materials (PCMs). In this paper, the light bio-oil, as one of the by-products of biomass pyrolysis, was proposed to pretreat poplar powder to investigate the influence on the properties of the PCMs obtained under ZnCl₂ activation. The Scanning electron microscopy (SEM) analysis showed that the surface morphology of the biomass was seriously destroyed by light bio-oil treatment. And, the relative crystallinity of the biomass increased after the treatment based on the X-ray diffraction (XRD) analysis. Correspondingly, the obtained PCMs with the help of light bio-oil treatment have the better reasonable hierarchical pore structure and electrochemical performances. The specific surface area of PCMs obtained from light bio-oil pretreatment together with ZnCl₂ activation at 500 °C reached 2063.8 m²/g. Its specific capacitance reached 306.5 F/g at 0.5 A/g. The symmetric supercapacitor assembled with the corresponding PCMs also exhibited excellent performance. The energy density reached 8.69 Wh kg⁻¹ at 125 W kg⁻¹. After undergoing 10,000 cycle tests, the capacitance retention rate was 98.46 %. This paper can provide some reference significance on the pathway for the preparation of supercapacitor electrode materials from biomass resources.
Integrated approach for H<inf>2</inf>-Rich syngas production from wastes using carbon-based catalysts and subsequent CO<inf>2</inf> adsorption by carbon-based adsorbents: A review
2024, International Journal of Hydrogen Energy
The shift towards sustainable energy systems has led to an exploration of hydrogen (H₂) as a sustainable and eco-friendly fuel substitute. This article explores significant progress in carbon-based catalysts (CBCs) for H₂-rich syngas production from wastes via pyro-steam gasification, as well as the application of carbon-based adsorbents (CBAs) for carbon dioxide (CO₂) adsorption to enhance H₂ ratio in syngas. It also examines the efficacy of several catalysts supported on carbon materials (char and activated carbon). These catalysts include transition metals, noble metals, and alkali metals. Furthermore, the influence of operational parameters such as temperature, space velocity, steam-to-carbon ratio, feedstock composition, and catalyst particle size on H₂ production and CBC performance is examined. It also evaluates CBC production techniques, including precipitation, impregnation, physical mixing, and adsorption, emphasizing the advantages and disadvantages of these procedures in order to develop effective catalysts. Furthermore, the review examines CBAs, particularly char and activated carbon, for their CO₂ adsorption capacity and mechanisms, which include physisorption and chemisorption. A comparative analysis of activation methods for producing CBAs, such as physical and chemical activation, and their respective CO₂ adsorption efficiencies are also presented. The article concludes with valuable recommendations and insights on optimizing gasification and catalyst design for H₂-rich syngas production and improving CO₂ adsorption to promote integrated solutions for producing H₂.
Three-dimensional porous carbon materials as catalysts for upgrading coal pyrolysis volatiles to boost light tar
2024, Fuel
The large proportion of heavy components in volatiles from coal pyrolysis is liable to entrain dust and form coke, resulting in the difficulty of separating oil from dust, which thus causes the blocking of technical pipelines. Carbon-based catalysts (BC and BHC) and metal-modified carbon-based catalysts (Fe-BC, Ni-BC, Fe-BHC and Ni-BHC) were prepared for the upgrading of volatiles from coal pyrolysis. This three-dimensional interconnected macroporous carbon material is primarily derived from the pyrolysis of the blend of a biochar and a caking coal. The results show that the metal-modified carbon-based catalysts aid in activating small molecules, such as CH₄, CO₂, and H₂O, increasing in-situ hydrogen donation while cracking polycyclic aromatics, macromolecular oxygen-containing compounds, and N, S-containing heterocyclic compounds. This thus increases the selective catalysis of benzene, naphthalene, biphenyl, and anthracene and improves tar quality. The unactivated Fe-BC and Ni-BC catalysts exhibit high selectivity for light oil with a boiling point below 170 °C. In contrast, the activated Fe-BHC and Ni-BHC catalysts have a stronger ability to crack heavy tar due to the synergistic effect of metal and carbon defect structures. However, the micropores within the catalysts prevent mass transfer of macromolecular compounds, drastically lowering the tar yield with coke formation. Overall, the unactivated metal modified catalyst with three-dimensional porous structure allows for the synergistic effect of dust removal and upgrading of volatiles while maintaining the tar yield, especially the Fe-BC catalyst with a lower price.
Lignite-char-supported highly dispersed ultrasmall Ni-Co alloy for stably dry reforming of methane at low temperature
2023, Chemical Engineering Science
Lignite, abundant in oxygen-containing functional groups, can disperse metal ions through an ion-exchanging method to prepare highly dispersed metal catalysts. Herein, we prepared the Ni-Co bimetallic catalysts using this method and tested their activity and stability in the dry reforming of methane reaction. The Ni_0.05-Co_0.1 with Ni/Co mass ratio of 1:10 exhibited superior performance due to its higher specific surface area (386 m²/g), smaller metallic particle size (4.85 nm), better dispersion and moderate basicity (0.023 mmol/g), showing the best activity at 650 °C, 2400 mL.h⁻¹.g⁻¹ and atmospheric pressure, with a conversion of 71.5% for CH₄, 82.8% for CO₂, and a molar ratio of H₂/CO of 0.73. Additionally, the catalyst maintained a stable activity throughout a continuous 30 h test at 650 °C, 7200 mL.h⁻¹.g⁻¹ and 0.3 MPa. Overall, this study demonstrates that lignite-char-supported Ni-Co alloy catalysts show great potential for DRM reaction particularly at relatively low temperature and elevated pressure.
Specific cleavage of >CH-O-bonds in benzyloxybenzene and poplar lignin over nickel supported on a nitrogen-doped carbon material
2023, Fuel Processing Technology
Nickel supported on a nitrogen-doped carbon material (NDCM) was successfully prepared and used for catalyzing the hydroconversion of benzyloxybenzene (BOB) and poplar lignin (PL). Over Ni/NDCM, BOB was completely converted to toluene and phenol in the yields of 75.5 and 73.1 mol%, respectively, under initial hydrogen pressure (IHP) of 2 MPa at 240 °C for 2 h. The adsorption energies (AEs) of different systems were calculated using the density functional theory. The AEs of H₂ on Ni (111), Ni (200), and Ni (220) crystal planes are −1.26, −1.27, and − 1.28 eV, respectively, indicating that Ni (111) crystal plane is the most active for splitting H₂ to mobile H⁺ and immobile H⁻, the higher absolute value of AE (−2.5 eV) of BOB on Ni/NDCM facilitates BOB hydrocracking. Moreover, Ni/NDCM could promote the cleavage of >CH-O- bonds in PL to produce more phenols.
Methanation of CO/CO<inf>2</inf> for power to methane process: Fundamentals, status, and perspectives
2023, Journal of Energy Chemistry
Power-to-methane (P2M) processes, by converting electricity from renewable energy to H₂ and then into other high value-added and energy-intense chemicals in the presence of active catalysts, have become an effective solution for energy storage. However, the fluctuating electricity from intermittent renewable energy leads to a dynamic composition of reactants for downstream methanation, which requires an excellent heterogeneous catalyst to withstand the harsh conditions. Based on these findings, the objective of this review is to classify the fundamentals and status of CO/CO₂ methanation and identify the pathways in the presence of various catalysts for methane production. In addition, this review sheds insight into the future development and challenges of CO₂ or CO methanation, including the deactivation mechanisms and catalyst performance under dynamically harsh conditions. Finally, we elaborated on the advantages and development prospects of P2M, and then we summarized the current stage and ongoing industrialization projects of P2M.

View all citing articles on Scopus

View full text

Full Length ArticlePreparation of high-dispersion Ni/C catalyst using modified lignite as carbon precursor for catalytic reforming of biomass volatiles

Highlights

Abstract

Graphical abstract

Introduction

Section snippets

Preparation of acid washed, demineralized and oxidized lignite

FTIR analysis

Conclusions

Acknowledgements

J Anal Appl Pyrol

Fuel Process Technol

Fuel

Fuel Process Technol

Fuel Process Technol

Fuel Process Technol

Fuel

Int J Hydrogen Energy

Fuel

Int J Hydrogen Energ

Mar Pollut Bull

Fuel

Fuel

Fuel

Fuel

Fuel

Fuel

Fuel

Full Length Article
Preparation of high-dispersion Ni/C catalyst using modified lignite as carbon precursor for catalytic reforming of biomass volatiles