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Progress on Catalyst Development for the Reforming of Biomass and Pyrolysis Volatiles

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A special issue of Molecules (ISSN 1420-3049). This special issue belongs to the section "Green Chemistry".

Deadline for manuscript submissions: closed (30 November 2023) | Viewed by 6488

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Special Issue Editors

Dr. Laura Santamaria

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Guest Editor

Department of Chemical Engineering, University of the Basque Country, Leioa, Spain
Interests: biomass; catalyst; steam reforming; pyrolysis; hydrogen
Special Issues, Collections and Topics in MDPI journals

Dr. Maria Cortazar

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Guest Editor

Department of Chemical Engineering, University of the Basque Country, Leioa, Spain
Interests: biomass; catalyst; steam gasification; pyrolysis; hydrogen

Special Issue Information

Dear Colleagues,

The current environmental concerns associated with the depletion of fossil fuels are promoting the required change toward the development of alternative routes aimed at the production of clean energy. In this scenario, technologies for H₂production from sustainable sources will play an essential role in this renewable energy transition and, therefore, in the reduction of CO₂ emissions and related problems such as climate change. In this regard, biomass pyrolysis and in-line catalytic steam reforming is a promising alternative for the production of hydrogen from renewable sources.

The scaling up of this process is conditioned by fast catalyst deactivation due to coke deposition on the reforming catalyst. Therefore, suitable design of the reforming catalysts is crucial for improving catalyst activity, selectivity, and stability.

This Special Issue of Molecules is focused on covering recent progress on the development of metal-based catalysts in the steam reforming of biomass pyrolysis volatiles and bio-oil compounds. Original research papers and short reviews dealing with the optimization of process conditions, synthesis of reforming catalysts, knowledge of catalyst deactivation, and reactor design and configuration are especially encouraged.

Dr. Laura Santamaria
Dr. Maria Cortazar
Guest Editors

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Keywords

steam reforming
Ni-based catalyst
biomass
bio-oil
hydrogen
pyrolysis-reforming
deactivation

Published Papers (4 papers)

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Research

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17 pages, 2981 KiB

Open AccessArticle

Study on the Relationship between the Structure and Pyrolysis Characteristics of Lignin Isolated from Eucalyptus, Pine, and Rice Straw through the Use of Deep Eutectic Solvent

by Tengfei Li, Xin Jin, Xinyao Shen, Hangdan Liu, Ruiping Tong, Xuzhen Qiu and Junfei Xu

Molecules 2024, 29(1), 219; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules29010219 - 30 Dec 2023

Viewed by 789

Abstract

Understanding the pyrolysis product distributions of deep eutectic solvent (DES)-isolated lignins (DESLs) from different types of biomass is of great significance for lignin valorization. The structure and pyrolysis properties of DESLs obtained from eucalyptus (E-DESL), pine (P-DESL), and rice straw (R-DESL) were studied through the use of various methods such as elemental analysis, GPC, HS-GC, and NMR techniques, and the pyrolysis characteristics and product distributions of the DESLs were also further investigated through the use of TGA, Py-GC/MS, and tubular furnace pyrolysis. DESLs with high purity (88.5–92.7%) can be efficiently separated from biomass while cellulose is retained. E-DESL has a relatively low molecular weight, and P-DESL has a relatively higher hydrogen–carbon effective ratio and a lower number of condensation structures. The Py-GC/MS results show that, during DESL pyrolysis, the monomeric aromatic hydrocarbons, p-hydroxyphenyl-type phenols, and catechol-type phenols are gradually released when the guaiacyl-type phenols and syringyl-type phenols decrease with the rising temperature. 4-methylguaiacol and 4-methylcatechol, derived from the guaiacyl-type structural units, are positively correlated with temperature, which causes a significant increase in products with a side-chain carbon number of 1 from P-DESL pyrolysis. 4-vinylphenol, as a representative product of the R-DESL, derived from p-hydroxyphenyl-type structural units, also gradually increased. In addition, the P-DESL produces more bio-oil during pyrolysis, while gases have the highest distribution in E-DESL pyrolysis. It is of great significance to study the characteristic product distribution of lignin isolated through the use of DES for lignin directional conversion into specific high-value aromatic compounds. Full article

(This article belongs to the Special Issue Progress on Catalyst Development for the Reforming of Biomass and Pyrolysis Volatiles)

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11 pages, 4175 KiB

Open AccessArticle

Effects of P:Ni Ratio on Methanol Steam Reforming on Nickel Phosphide Catalysts

by Abdulrahman Almithn

Molecules 2023, 28(16), 6079; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules28166079 - 16 Aug 2023

Viewed by 757

Abstract

This study investigates the influence of the phosphorus-to-nickel (P:Ni) ratio on methanol steam reforming (MSR) over nickel phosphide catalysts using density functional theory (DFT) calculations. The catalytic behavior of Ni(111) and Ni₁₂P₅(001) surfaces was explored and contrasted to our previous results from research on Ni₂P(001). The DFT-predicted barriers reveal that Ni(111) predominantly favors the methanol decomposition route, where methanol is converted into carbon monoxide through a stepwise pathway involving CH₃OH* → CH₃O* → CH₂O* → CHO* → CO*. On the other hand, Ni₁₂P₅ with a P:Ni atomic ratio of 0.42 (5:12) exhibits a substantial increase in selectivity towards methanol steam reforming (MSR) relative to methanol decomposition. In this pathway, formaldehyde is transformed into CO₂ through a sequence of reactions involving CH₂O*→ H₂COOH* → HCOOH* → HCOO* → CO₂. The introduction of phosphorus into the catalyst alters the surface morphology and electronic structure, favoring the MSR pathway. However, with a further increase in the P:Ni atomic ratio to 0.5 (1:2) on Ni₂P catalysts, the selectivity towards MSR decreases, resulting in a more balanced competition between methanol decomposition and MSR. These results highlight the significance of tuning the P:Ni atomic ratio in designing efficient catalysts for the selective production of CO₂ through the MSR route, offering valuable insights into optimizing nickel phosphide catalysts for desired chemical transformations. Full article

(This article belongs to the Special Issue Progress on Catalyst Development for the Reforming of Biomass and Pyrolysis Volatiles)

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18 pages, 4048 KiB

Open AccessArticle

Conversion of Waste Cooking Oil into Bio-Fuel via Pyrolysis Using Activated Carbon as a Catalyst

by Warintorn Banchapattanasakda, Channarong Asavatesanupap and Malee Santikunaporn

Molecules 2023, 28(8), 3590; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules28083590 - 20 Apr 2023

Cited by 7 | Viewed by 2613

Abstract

The utilization of activated carbon (AC) as a catalyst for a lab-scale pyrolysis process to convert waste cooking oil (WCO) into more valuable hydrocarbon fuels is described. The pyrolysis process was performed with WCO and AC in an oxygen-free batch reactor at room pressure. The effects of process temperature and activated carbon dosage (the AC to WCO ratio) on the yield and composition are discussed systematically. The direct pyrolysis experimental results showed that WCO pyrolyzed at 425 °C yielded 81.7 wt.% bio-oil. When AC was used as a catalyst, a temperature of 400 °C and 1:40 AC:WCO ratio were the optimum conditions for the maximum hydrocarbon bio-oil yield of 83.5 and diesel-like fuel of 45 wt.%, investigated by boiling point distribution. Compared to bio-diesel and diesel properties, bio-oil has a high calorific value (40.20 kJ/g) and a density of 899 kg/m³, which are within the bio-diesel standard range, thus demonstrating its potential use as a liquid bio-fuel after certain upgradation processes. The study revealed that the optimum AC dosage promoted the thermal cracking of WCO at a reduced process temperature with a higher yield and improved quality compared to noncatalytic bio-oil. Full article

(This article belongs to the Special Issue Progress on Catalyst Development for the Reforming of Biomass and Pyrolysis Volatiles)

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Review

Jump to: Research

30 pages, 2841 KiB

Open AccessReview

A Review on Catalytic Fast Co-Pyrolysis Using Analytical Py-GC/MS

by Sabah Mariyam, Shifa Zuhara, Prakash Parthasarathy and Gordon McKay

Molecules 2023, 28(5), 2313; https://0-doi-org.brum.beds.ac.uk/10.3390/molecules28052313 - 02 Mar 2023

Cited by 3 | Viewed by 1821

Abstract

Py-GC/MS combines pyrolysis with analytical tools of gas chromatography (GC) and mass spectrometry (MS) and is a quick and highly effective method to analyse the volatiles generated from small amounts of feeds. The review focuses on using zeolites and other catalysts in the fast co-pyrolysis of various feedstocks, including biomass wastes (plants and animals) and municipal waste materials, to improve the yield of specific volatile products. The utilisation of zeolite catalysts, including HZSM-5 and nMFI, results in a synergistic reduction of oxygen and an increase in the hydrocarbon content of pyrolysis products. The literature works also indicate HZSM-5 produced the most bio-oil and had the least coke deposition among the zeolites tested. Other catalysts, such as metals and metal oxides, and feedstocks that act as catalysts (self-catalysis), such as red mud and oil shale, are also discussed in the review. Combining catalysts, such as metal oxides and HZSM-5, further improves the yields of aromatics during co-pyrolysis. The review highlights the need for further research on the kinetics of the processes, optimisation of feed-to-catalyst ratios, and stability of catalysts and products. Full article

(This article belongs to the Special Issue Progress on Catalyst Development for the Reforming of Biomass and Pyrolysis Volatiles)

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