Catalysts

Research

Jump to: Review

13 pages, 1990 KiB

Open AccessFeature PaperArticle

Hydrogenation of Aqueous Acetic Acid over Ru-Sn/TiO₂ Catalyst in a Flow-Type Reactor, Governed by Reverse Reaction

by Yuanyuan Zhao, Kansei Konishi, Eiji Minami, Shiro Saka and Haruo Kawamoto

Catalysts 2020, 10(11), 1270; https://doi.org/10.3390/catal10111270 - 2 Nov 2020

Cited by 1 | Viewed by 3613

Abstract

Ru-Sn/TiO₂ is an effective catalyst for hydrogenation of aqueous acetic acid to ethanol. In this paper, a similar hydrogenation process was investigated in a flow-type rather than a batch-type reactor. The optimum temperature was 170 °C for the batch-type reactor because of [...] Read more.

Ru-Sn/TiO₂ is an effective catalyst for hydrogenation of aqueous acetic acid to ethanol. In this paper, a similar hydrogenation process was investigated in a flow-type rather than a batch-type reactor. The optimum temperature was 170 °C for the batch-type reactor because of gas production at higher temperatures; however, for the flow-type reactor, the ethanol yield increased with reaction temperature up to 280 °C and then decreased sharply above 300 °C, owing to an increase in the acetic acid recovery rate. The selectivity for ethanol formation was improved over the batch process, and an ethanol yield of 98 mol % was achieved for a 6.7 min reaction (cf. 12 h for batch) (liquid hourly space velocity: 1.23 h⁻¹). Oxidation of ethanol to acetic acid (i.e., the reverse reaction) adversely affected the hydrogenation. On the basis of these results, hydrogenation mechanisms that include competing side reactions are discussed in relation to the reactor type. These results will help the development of more efficient catalytic procedures. This method was also effectively applied to hydrogenation of lactic acid to propane-1,2-diol. Full article

(This article belongs to the Special Issue Perspectives in Catalytic Fast Pyrolysis, Catalytic Hydrodeoxygenation, and Catalytic Fast Hydropyrolysis)

► Show Figures

Graphical abstract

10 pages, 2304 KiB

Open AccessArticle

Catalytic Fast Pyrolysis of Biomass into Aromatic Hydrocarbons over Mo-Modified ZSM-5 Catalysts

by Laizhi Sun, Zhibin Wang, Lei Chen, Shuangxia Yang, Xinping Xie, Mingjie Gao, Baofeng Zhao, Hongyu Si, Jian Li and Dongliang Hua

Catalysts 2020, 10(9), 1051; https://doi.org/10.3390/catal10091051 - 12 Sep 2020

Cited by 25 | Viewed by 3001

Abstract

Mo-modified ZSM-5 catalysts were prepared and used to produce aromatic hydrocarbons during catalytic fast pyrolysis (CFP) of biomass. The composition and distribution of aromatics were investigated on pyrolysis–gas chromatography/mass spectrometry (Py-GC/MS). The reaction factors, such as the Mo content, the reaction temperature and [...] Read more.

Mo-modified ZSM-5 catalysts were prepared and used to produce aromatic hydrocarbons during catalytic fast pyrolysis (CFP) of biomass. The composition and distribution of aromatics were investigated on pyrolysis–gas chromatography/mass spectrometry (Py-GC/MS). The reaction factors, such as the Mo content, the reaction temperature and the catalyst/biomass mass ratio, were also optimized. It was found that the 10Mo/ZSM-5 catalyst displayed the best activity in improving the production of monocyclic aromatic hydrocarbons (MAHs) and decreasing the yield of polycyclic aromatic hydrocarbons (PAHs) at 600 °C and with a catalyst/biomass ratio of 10. Furthermore, according to catalyst characterization and the experiment results, the aromatics formation mechanism over Mo/ZSM-5 catalysts was also summarized and proposed. Full article

(This article belongs to the Special Issue Perspectives in Catalytic Fast Pyrolysis, Catalytic Hydrodeoxygenation, and Catalytic Fast Hydropyrolysis)

► Show Figures

Figure 1

17 pages, 3837 KiB

Open AccessArticle

High Performance and Sustainable Copper-Modified Hydroxyapatite Catalysts for Catalytic Transfer Hydrogenation of Furfural

by Balla Putrakumar, Prem Kumar Seelam, Ginjupalli Srinivasarao, Karthikeyan Rajan, Rajendiran Rajesh, K. Ramachandra Rao and Tongxiang Liang

Catalysts 2020, 10(9), 1045; https://doi.org/10.3390/catal10091045 - 11 Sep 2020

Cited by 25 | Viewed by 4765

Abstract

Designing and developing non-noble metal-based heterogeneous catalysts have a substantial importance in biomass conversion. Meerwein-Ponndorf-Verley (MPV) reaction is a significant pathway for eco-friendly catalytic transfer hydrogenation (CTH) of biomass derived furfural into furfuryl alcohol. In this work, a series of copper-supported hydroxyapatite (HAp) [...] Read more.

Designing and developing non-noble metal-based heterogeneous catalysts have a substantial importance in biomass conversion. Meerwein-Ponndorf-Verley (MPV) reaction is a significant pathway for eco-friendly catalytic transfer hydrogenation (CTH) of biomass derived furfural into furfuryl alcohol. In this work, a series of copper-supported hydroxyapatite (HAp) catalysts with different copper loadings (2–20 wt.%) were prepared by a facile impregnation method and tested in the reduction of furfural to furfuryl alcohol using 2-propanol as a hydrogen donor. The structural and chemical properties of the synthesised catalysts were analysed by using various techniques (XRD, N₂ sorption, SEM, TEM, UV-DRS, ICP, FTIR, TPR, TPD-CO₂ and N₂O titration). The effect of copper loading was found to be significant on the total performance of the catalysts. The results demonstrate that 5CuHAp catalyst possess highly dispersed copper particles and high basicity compared to all other catalysts. Overall, 5CuHAp exhibited highest conversion (96%) and selectivity (100%) at 140 °C at 4 h time on stream. The optimised reaction conditions were also determined to gain the high activity. Full article

(This article belongs to the Special Issue Perspectives in Catalytic Fast Pyrolysis, Catalytic Hydrodeoxygenation, and Catalytic Fast Hydropyrolysis)

► Show Figures

Graphical abstract

19 pages, 6806 KiB

Open AccessArticle

Hydrocarbon Production from Catalytic Pyrolysis-GC/MS of Sacha Inchi Residues Using SBA-15 Derived from Coal Fly Ash

by Chakrit Soongprasit, Duangdao Aht-Ong, Viboon Sricharoenchaikul, Supawan Vichaphund and Duangduen Atong

Catalysts 2020, 10(9), 1031; https://doi.org/10.3390/catal10091031 - 8 Sep 2020

Cited by 11 | Viewed by 3518

Abstract

In this work, Sacha inchi (Plukenetia volubilis L.) residues were used as biomass feedstocks in catalytic upgrading pyrolysis with SBA-15, which is a substance synthesized from coal fly ash (CFA), using alkali fusion, followed by hydrothermal treatment (SBA-15-FA). The catalytic activity of [...] Read more.

In this work, Sacha inchi (Plukenetia volubilis L.) residues were used as biomass feedstocks in catalytic upgrading pyrolysis with SBA-15, which is a substance synthesized from coal fly ash (CFA), using alkali fusion, followed by hydrothermal treatment (SBA-15-FA). The catalytic activity of fly ash-derived SBA-15 was investigated through the fast pyrolysis of Sacha inchi residues for upgrading the pyrolysis vapors using the analytical pyrolysis-GC/MS (Py-GC/MS) technique. The pyrolysis temperature was set at 500 °C and held for 30 s while maintaining the Sacha inchi residues to catalyst ratios of 1:0, 1:1, 1:5, and 1:10. In addition, the SBA-15s synthesized from chemical reagent and commercial SBA-15 were evaluated for comparison. The non-catalytic fast pyrolysis of Sacha inchi (SI) mainly consisted of fatty acids (46%), including chiefly linoleic acid (C18:2). Other compounds present were hydrocarbon (26%) and nitrogen-containing compounds (8.7%), esters (9.0%), alcohols (6.4%), and furans (3.6%). The study results suggested that the SBA-15-FA showcased a high ability to improve aliphatic selectivity (mainly C₅–C₂₀) and was found to be almost 80% at the biomass to catalyst ratio of 1:5. Moreover, the increase in catalyst contents affected the enhancement of hydrocarbons yields and tended to promote the deoxygenation reaction. Interestingly, the catalytic performance of SBA-15 derived from fly ash could be compared to that of the commercial SBA-15 in terms of producing hydrocarbon compounds as well as reducing oxygenated compounds. Full article

(This article belongs to the Special Issue Perspectives in Catalytic Fast Pyrolysis, Catalytic Hydrodeoxygenation, and Catalytic Fast Hydropyrolysis)

► Show Figures

Graphical abstract

19 pages, 4173 KiB

Open AccessArticle

Counteracting Rapid Catalyst Deactivation by Concomitant Temperature Increase during Catalytic Upgrading of Biomass Pyrolysis Vapors Using Solid Acid Catalysts

by Andreas Eschenbacher, Alireza Saraeian, Brent H. Shanks, Uffe Vie Mentzel, Jesper Ahrenfeldt, Ulrik Birk Henriksen and Anker Degn Jensen

Catalysts 2020, 10(7), 748; https://doi.org/10.3390/catal10070748 - 6 Jul 2020

Cited by 8 | Viewed by 3350

Abstract

The treatment of biomass-derived fast pyrolysis vapors with solid acid catalysts (in particular HZSM-5 zeolite) improves the quality of liquid bio-oils. However, due to the highly reactive nature of the oxygenates, the catalysts deactivate rapidly due to coking. Within this study, the deactivation [...] Read more.

The treatment of biomass-derived fast pyrolysis vapors with solid acid catalysts (in particular HZSM-5 zeolite) improves the quality of liquid bio-oils. However, due to the highly reactive nature of the oxygenates, the catalysts deactivate rapidly due to coking. Within this study, the deactivation and product yields using steam-treated phosphorus-modified HZSM-5/γ-Al₂O₃ and bare γ-Al₂O₃ was studied with analytical Py-GC. While at a fixed catalyst temperature of 450 °C, a rapid breakthrough of oxygenates was observed with increased biomass feeding, this breakthrough was delayed and slower at higher catalyst temperatures (600 °C). Nevertheless, at all (constant) temperatures, there was a continuous decrease in the yield of oxygen-free hydrocarbons with increased biomass feeding. Raising the reaction temperature during the vapor treatment could successfully compensate for the loss in activity and allowed a more stable production of oxygen-free hydrocarbons. Since more biomass could be fed over the same amount of catalyst while maintaining good deoxygenation performance, this strategy reduces the frequency of regeneration in parallel fixed bed applications and provides a more stable product yield. The approach appears particularly interesting for catalysts that are robust under hydrothermal conditions and warrants further investigations at larger scales for the collection and analysis of liquid bio-oil. Full article

(This article belongs to the Special Issue Perspectives in Catalytic Fast Pyrolysis, Catalytic Hydrodeoxygenation, and Catalytic Fast Hydropyrolysis)

► Show Figures

Figure 1

12 pages, 3282 KiB

Open AccessArticle

Synthesis of Valeric Acid by Selective Electrocatalytic Hydrogenation of Biomass-Derived Levulinic Acid

by Yan Du, Xiao Chen, Ji Qi, Pan Wang and Changhai Liang

Catalysts 2020, 10(6), 692; https://doi.org/10.3390/catal10060692 - 19 Jun 2020

Cited by 18 | Viewed by 4169

Abstract

The electrocatalytic hydrogenation (ECH) of biomass-derived levulinic acid (LA) is a promising strategy to synthetize fine chemicals under ambient conditions by replacing the thermocatalytic hydrogenation at high temperature and high pressure. Herein, various metallic electrodes were investigated in the ECH of LA in [...] Read more.

The electrocatalytic hydrogenation (ECH) of biomass-derived levulinic acid (LA) is a promising strategy to synthetize fine chemicals under ambient conditions by replacing the thermocatalytic hydrogenation at high temperature and high pressure. Herein, various metallic electrodes were investigated in the ECH of LA in a H-type divided cell. The effects of potential, electrolyte concentration, reactant concentration, and temperature on catalytic performance and Faradaic efficiency were systematically explored. The high conversion of LA (93%) and excellent “apparent” selectivity to valeric acid (VA) (94%) with a Faradaic efficiency of 46% can be achieved over a metallic lead electrode in 0.5 M H₂SO₄ electrolyte containing 0.2 M LA at an applied voltage of −1.8 V (vs. Ag/AgCl) for 4 h. The combination of adsorbed LA and adsorbed hydrogen (H_ads) on the surface of the metallic lead electrode is key to the formation of VA. Interestingly, the reaction performance did not change significantly after eight cycles, while the surface of the metallic lead cathode became rough, which may expose more active sites for the ECH of LA to VA. However, there was some degree of corrosion for the metallic lead cathode in this strong acid environment. Therefore, it is necessary to improve the leaching-resistance of the cathode for the ECH of LA in future research. Full article

(This article belongs to the Special Issue Perspectives in Catalytic Fast Pyrolysis, Catalytic Hydrodeoxygenation, and Catalytic Fast Hydropyrolysis)

► Show Figures

Graphical abstract

20 pages, 8138 KiB

Open AccessArticle

Stabilization of Fast Pyrolysis Liquids from Biomass by Mild Catalytic Hydrotreatment: Model Compound Study

by Depeng Han, Wang Yin, Ali Arslan, Tongrui Liu, Yan Zheng and Shuqian Xia

Catalysts 2020, 10(4), 402; https://doi.org/10.3390/catal10040402 - 7 Apr 2020

Cited by 8 | Viewed by 2796

Abstract

Repolymerization is a huge problem in the storage and processing of biomass pyrolysis liquid (PL). Herein, to solve the problem of repolymerization, mild catalytic hydrotreatment of PL was conducted to convert unstable PL model compounds (hydroxyacetone, furfural, and phenol) into stable alcohols. An [...] Read more.

Repolymerization is a huge problem in the storage and processing of biomass pyrolysis liquid (PL). Herein, to solve the problem of repolymerization, mild catalytic hydrotreatment of PL was conducted to convert unstable PL model compounds (hydroxyacetone, furfural, and phenol) into stable alcohols. An Ni/SiO₂ catalyst was synthesized by the deposition-precipitation method and used in a mild hydrotreatment process. The mild hydrotreatment of the single model compound was studied to determine the reaction pathways, which provided guidance for improving the selectivity of stable intermediate alcohols through the control of reaction conditions. More importantly, the mild hydrotreatment of mixed model compounds was evaluated to simulate the PL more factually. In addition, the effect of the interaction between hydroxyacetone, furfural, and phenol during the catalytic hydrotreatment was also explored. There was a strange phenomenon observed in that phenol was not converted in the initial stage of the hydrotreatment of mixed model compounds. Thermogravimetric analysis (TGA), Ultraviolet-Raman (UV-Raman), and Brunauer−Emmett−Teller (BET) characterization of catalysts used in the hydrotreatment of single and mixed model compounds demonstrated that this phenomenon did not mainly arise from the irreversible deactivation of catalysts caused by carbon deposition, but the competitive adsorption among hydroxyacetone, furfural, and phenol during the mild hydrotreatment of mixed model compounds. Full article

(This article belongs to the Special Issue Perspectives in Catalytic Fast Pyrolysis, Catalytic Hydrodeoxygenation, and Catalytic Fast Hydropyrolysis)

► Show Figures

Figure 1

12 pages, 2755 KiB

Open AccessArticle

Hydrogenolysis of Glycerol on the ZrO₂-TiO₂ Supported Pt-WO_x Catalyst

by Zhiwen Xi, Zhe Hong, Fangtao Huang, Zhirong Zhu, Wenzhi Jia and Junhui Li

Catalysts 2020, 10(3), 312; https://doi.org/10.3390/catal10030312 - 9 Mar 2020

Cited by 14 | Viewed by 3447

Abstract

A series of Pt/WOx-ZrO₂-TiO₂ catalysts with different Ti/Zr molar ratios was prepared by an evaporation induced self-assembly method, and used to efficient hydrogenolysis of glycerol to 1-PO and 1,3-PDO. BET, XRD, Raman, TEM, XPS and Py-IR were employed to characterize [...] Read more.

A series of Pt/WOx-ZrO₂-TiO₂ catalysts with different Ti/Zr molar ratios was prepared by an evaporation induced self-assembly method, and used to efficient hydrogenolysis of glycerol to 1-PO and 1,3-PDO. BET, XRD, Raman, TEM, XPS and Py-IR were employed to characterize the physicochemical properties of the catalysts. The structural and acidic properties of the catalysts were affected by the Ti/Zr ratio of the support ZrO₂-TiO₂. Two new crystalline phases of ZrTiO₄ and Ti₂ZrO₆ and the amount of acid sites were detected in the Pt/WOx-ZrO₂-TiO₂ catalysts. 1-PO is dominant in all products of glycerol hydrogenolysis over the supported Pt-WOx catalysts, which is attributed to more Lewis acid sites on the catalyst surface. The Pt/WOx-ZrO₂-TiO₂ catalyst with a Ti/Zr ratio of 7/3 showed the highest 1,3-PDO yield (25.3%) and 1-PO yield (42.3%), due to its more acid sites including Brønsted and Lewis, and higher concentration of surface Pt⁰. Full article

(This article belongs to the Special Issue Perspectives in Catalytic Fast Pyrolysis, Catalytic Hydrodeoxygenation, and Catalytic Fast Hydropyrolysis)

► Show Figures

Figure 1

9 pages, 1271 KiB

Open AccessArticle

A Study of the Mechanisms of Guaiacol Pyrolysis Based on Free Radicals Detection Technology

by Guoxiang Li, Zhongyang Luo, Wenbo Wang and Jianmeng Cen

Catalysts 2020, 10(3), 295; https://doi.org/10.3390/catal10030295 - 5 Mar 2020

Cited by 24 | Viewed by 4015

Abstract

In order to understand the reaction mechanism of lignin pyrolysis, the pyrolysis process of guaiacol (o-methoxyphenol) as a lignin model compound was studied by free radical detection technology (electron paramagnetic resonance, EPR) in this paper. It was proven that the pyrolysis reaction of [...] Read more.

In order to understand the reaction mechanism of lignin pyrolysis, the pyrolysis process of guaiacol (o-methoxyphenol) as a lignin model compound was studied by free radical detection technology (electron paramagnetic resonance, EPR) in this paper. It was proven that the pyrolysis reaction of guaiacol is a free radical reaction, and the free radicals which can be detected mainly by EPR are methyl radicals. This paper proposes a process in which four free radicals (radicals 1- C₆H₄(OH)O*, radicals 5- C₆H₄(OCH₃)O*, methyl radicals, and hydrogen radicals) are continuously rearranged during the pyrolysis of guaiacol. Full article

(This article belongs to the Special Issue Perspectives in Catalytic Fast Pyrolysis, Catalytic Hydrodeoxygenation, and Catalytic Fast Hydropyrolysis)

► Show Figures

Figure 1

21 pages, 4961 KiB

Open AccessArticle

Hydrodeoxygenation of Levulinic Acid Dimers on a Zirconia-Supported Ruthenium Catalyst

by Eveliina Mäkelä, José Luis González Escobedo, Marina Lindblad, Mats Käldström, Heidi Meriö-Talvio, Hua Jiang, Riikka L. Puurunen and Reetta Karinen

Catalysts 2020, 10(2), 200; https://doi.org/10.3390/catal10020200 - 7 Feb 2020

Cited by 12 | Viewed by 3884

Abstract

The hydrodeoxygenation (HDO) of levulinic acid (LA) aldol condensation product dimers was studied between 250 and 300 °C and 50 bar H₂ in a batch reactor with Ru catalyst supported on mesoporous zirconia. During the reaction, the unsaturated dimers, which contained ketone [...] Read more.

The hydrodeoxygenation (HDO) of levulinic acid (LA) aldol condensation product dimers was studied between 250 and 300 °C and 50 bar H₂ in a batch reactor with Ru catalyst supported on mesoporous zirconia. During the reaction, the unsaturated dimers, which contained ketone groups and double bonds, were hydrogenated to saturated dimers. A greater degree of deoxygenation was achieved at higher temperatures, and oxygen was removed as water and CO₂. Oxygen removal was evidenced by elemental analysis and infrared spectroscopy, in which the C=O peak decreased with increasing temperature. A drawback of high reaction temperature (300 °C) was a minor degree of oligomerization. The formation of aromatics was also observed at the higher temperatures. Aside from the saturated dimers, volatile products were obtained at all temperatures, including ketones, acids, and esters. This study demonstrates for the first time the potential of LA dimers as a sustainable route from lignocellulosic biomass to biofuels and biocomponents. Full article

(This article belongs to the Special Issue Perspectives in Catalytic Fast Pyrolysis, Catalytic Hydrodeoxygenation, and Catalytic Fast Hydropyrolysis)

► Show Figures

Graphical abstract

12 pages, 1788 KiB

Open AccessFeature PaperArticle

Homogeneous and Heterogeneous Catalysis Impact on Pyrolyzed Cellulose to Produce Bio-Oil

by Siyi Li, Shuo Cheng and Jeffrey S. Cross

Catalysts 2020, 10(2), 178; https://doi.org/10.3390/catal10020178 - 3 Feb 2020

Cited by 14 | Viewed by 4378

Abstract

Effectively utilizing catalytic pyrolysis to upgrade bio-oil products prepared from biomass has many potential benefits for the environment. In this paper, cellulose (a major component of plants and a biomass model compound) is pyrolyzed and catalyzed with different catalysts: Ni₂Fe₃ [...] Read more.

Effectively utilizing catalytic pyrolysis to upgrade bio-oil products prepared from biomass has many potential benefits for the environment. In this paper, cellulose (a major component of plants and a biomass model compound) is pyrolyzed and catalyzed with different catalysts: Ni₂Fe₃, ZSM-5, and Ni₂Fe₃/ZSM-5. Two different pyrolysis processes are investigated to compare homogeneous and heterogeneous catalysis influence on the products. The results indicate that the Ni₂Fe₃ cluster catalyst shows the best activity as a homogeneous catalysis. It can also be recycled repeatedly, increases the yield of bio-oil, and improves the quality of the bio-oil by decreasing the sugar concentration. Furthermore, it also catalyzes the formation of a small amount of hydrocarbon compounds. In the case of Ni₂Fe₃/ZSM-5 catalyst, it shows a lower yield of bio-oil but also decreases the sugar concentration significantly. Ni₂Fe₃, not only can it be used as homogeneous catalysis mixed with cellulose but also shows catalytic activity as a supported catalyst on ZSM-5, with higher catalytic activity than ZSM-5. These results indicate that the Ni₂Fe₃ catalyst has significant activity for potential use in industry to produce high quality bio-oil from biomass. Full article

(This article belongs to the Special Issue Perspectives in Catalytic Fast Pyrolysis, Catalytic Hydrodeoxygenation, and Catalytic Fast Hydropyrolysis)

► Show Figures

Graphical abstract

10 pages, 1205 KiB

Open AccessArticle

Fast Catalytic Pyrolysis of Dilaurin in the Presence of Sodium Carbonate Alone or Combined with Alumina

by Noyala Fonseca, Aline Pereira, Roger Fréty and Emerson Sales

Catalysts 2019, 9(12), 993; https://doi.org/10.3390/catal9120993 - 27 Nov 2019

Cited by 5 | Viewed by 3009

Abstract

The objective of this work was to study the fast pyrolysis of a diglyceride intermediate compound during the conversion of triglycerides to fatty acids, esters and/or hydrocarbons. Dilaurin was selected as a model compound. Pyrolysis was conducted in a micro-pyrolyzer coupled to GC-MS [...] Read more.

The objective of this work was to study the fast pyrolysis of a diglyceride intermediate compound during the conversion of triglycerides to fatty acids, esters and/or hydrocarbons. Dilaurin was selected as a model compound. Pyrolysis was conducted in a micro-pyrolyzer coupled to GC-MS equipment at 500, 550 and 600 °C for 15 s in the presence of sodium carbonate (Na₂CO₃) as the catalyst. Results were compared to pyrolysis data using γ-Al₂O₃ as a catalyst. At 600 °C with Na₂CO₃ almost total conversion of diglyceride was obtained, with the formation of 41.3% hydrocarbons (C3 to C13). In the same conditions using alumina as a catalyst 68.5% of hydrocarbons were obtained. Na₂CO₃ presented itself as an efficient feedstock modifier, allowing pre-cracking and partial deoxygenation of the load. The use of the Na₂CO₃ and γ-Al₂O₃ conjugated system in layers reduced the fatty acid content in the products, increasing both the reagent conversion and the hydrocarbon variety (C3 to C23). This work suggests that the use of a double bed catalytic reactor is suitable for performing a deoxygenating pretreatment and producing hydrocarbons compatible with current liquid fuels, being potentially useful for more complex raw materials such as those from biomass treatments. Full article

(This article belongs to the Special Issue Perspectives in Catalytic Fast Pyrolysis, Catalytic Hydrodeoxygenation, and Catalytic Fast Hydropyrolysis)

► Show Figures

Figure 1

14 pages, 3839 KiB

Open AccessArticle

Performance of Catalytic Fast Pyrolysis Using a γ-Al₂O₃ Catalyst with Compound Modification of ZrO₂ and CeO₂

by Zeyu Xue, Zhaoping Zhong, Bo Zhang and Chao Xu

Catalysts 2019, 9(10), 849; https://doi.org/10.3390/catal9100849 - 12 Oct 2019

Cited by 15 | Viewed by 3434

Abstract

To investigate the catalytic pyrolysis performance of complex metal oxide catalysts for biomass, γ-Al₂O₃ was prepared through the precipitation method, and then ZrO₂ and γ-Al₂O₃ were blended in the proportion of 2:8 using the co-precipitation method. [...] Read more.

To investigate the catalytic pyrolysis performance of complex metal oxide catalysts for biomass, γ-Al₂O₃ was prepared through the precipitation method, and then ZrO₂ and γ-Al₂O₃ were blended in the proportion of 2:8 using the co-precipitation method. Next, CeO₂ was loaded on the surface of the catalyst for further modification. The three catalysts, A, ZA and CZA, were obtained. The specific surface and acidity of the catalysts were characterized by nitrogen adsorption–desorption and NH₃-Temperature Programmed Desorption (NH₃-TPD) respectively. The catalytic pyrolysis performance of catalysts for bamboo residues was investigated by Pyrolysis gas chromatography mass spectrometry (Py-GC/MS). Chromatograms were analyzed for identification of the pyrolysis products and the relative amounts of each component were calculated. Experimental results indicated that catalyst A had a good catalytic activity for the fast pyrolysis of bamboo residues. The addition of ZrO₂ and CeO₂ could continuously enhance the acidity of the catalyst and further promote the pyrolysis of macromolecular compounds and deoxidation of oxygen-containing compounds. Finally, catalyst CZA, obtained by compound modification, could not only dramatically reduce the relative content of phenol, acid and aldehyde and other oxygen-containing compounds, but also achieved the maximum hydrocarbon yield of 23.38%. The catalytic performance of catalyst CZA improved significantly compared with catalyst A. Full article

(This article belongs to the Special Issue Perspectives in Catalytic Fast Pyrolysis, Catalytic Hydrodeoxygenation, and Catalytic Fast Hydropyrolysis)

► Show Figures

Figure 1

Review

Jump to: Research

24 pages, 4307 KiB

Open AccessFeature PaperReview

Catalyst Stability—Bottleneck of Efficient Catalytic Pyrolysis

by Jacek Grams and Agnieszka M. Ruppert

Catalysts 2021, 11(2), 265; https://doi.org/10.3390/catal11020265 - 16 Feb 2021

Cited by 31 | Viewed by 4513

Abstract

The pyrolysis of lignocellulosic biomass is one of the most promising methods of alternative fuels production. However, due to the low selectivity of this process, the quality of the obtained bio-oil is usually not satisfactory and does not allow for its direct use [...] Read more.

The pyrolysis of lignocellulosic biomass is one of the most promising methods of alternative fuels production. However, due to the low selectivity of this process, the quality of the obtained bio-oil is usually not satisfactory and does not allow for its direct use as an engine fuel. Therefore, there is a need to apply catalysts able to upgrade the composition of the mixture of pyrolysis products. Unfortunately, despite the increase in the efficiency of the thermal decomposition of biomass, the catalysts undergo relatively fast deactivation and their stability can be considered a bottleneck of efficient pyrolysis of lignocellulosic feedstock. Therefore, solving the problem of catalyst stability is extremely important. Taking that into account, we presented, in this review, the most important reasons for catalyst deactivation, including coke formation, sintering, hydrothermal instability, and catalyst poisoning. Moreover, we discussed the progress in the development of methods leading to an increase in the stability of the catalysts of lignocellulosic biomass pyrolysis and strengthening their resistance to deactivation. Full article

(This article belongs to the Special Issue Perspectives in Catalytic Fast Pyrolysis, Catalytic Hydrodeoxygenation, and Catalytic Fast Hydropyrolysis)

► Show Figures

Figure 1

28 pages, 9684 KiB

Open AccessReview

Upgrading of Oils from Biomass and Waste: Catalytic Hydrodeoxygenation

by Mai Attia, Sherif Farag and Jamal Chaouki

Catalysts 2020, 10(12), 1381; https://doi.org/10.3390/catal10121381 - 26 Nov 2020

Cited by 46 | Viewed by 5542

Abstract

The continuous demand for fossil fuels has directed significant attention to developing new fuel sources to replace nonrenewable fossil fuels. Biomass and waste are suitable resources to produce proper alternative fuels instead of nonrenewable fuels. Upgrading bio-oil produced from biomass and waste pyrolysis [...] Read more.

The continuous demand for fossil fuels has directed significant attention to developing new fuel sources to replace nonrenewable fossil fuels. Biomass and waste are suitable resources to produce proper alternative fuels instead of nonrenewable fuels. Upgrading bio-oil produced from biomass and waste pyrolysis is essential to be used as an alternative to nonrenewable fuel. The high oxygen content in the biomass and waste pyrolysis oil creates several undesirable properties in the oil, such as low energy density, instability that leads to polymerization, high viscosity, and corrosion on contact surfaces during storage and transportation. Therefore, various upgrading techniques have been developed for bio-oil upgrading, and several are introduced herein, with a focus on the hydrodeoxygenation (HDO) technique. Different oxygenated compounds were collected in this review, and the main issue caused by the high oxygen contents is discussed. Different groups of catalysts that have been applied in the literature for the HDO are presented. The HDO of various lignin-derived oxygenates and carbohydrate-derived oxygenates from the literature is summarized, and their mechanisms are presented. The catalyst’s deactivation and coke formation are discussed, and the techno-economic analysis of HDO is summarized. A promising technique for the HDO process using the microwave heating technique is proposed. A comparison between microwave heating versus conventional heating shows the benefits of applying the microwave heating technique. Finally, how the microwave can work to enhance the HDO process is presented. Full article

(This article belongs to the Special Issue Perspectives in Catalytic Fast Pyrolysis, Catalytic Hydrodeoxygenation, and Catalytic Fast Hydropyrolysis)

► Show Figures

Figure 1

26 pages, 363 KiB

Open AccessReview

Biomass Pyrolysis Technology by Catalytic Fast Pyrolysis, Catalytic Co-Pyrolysis and Microwave-Assisted Pyrolysis: A Review

by Junjian Liu, Qidong Hou, Meiting Ju, Peng Ji, Qingmei Sun and Weizun Li

Catalysts 2020, 10(7), 742; https://doi.org/10.3390/catal10070742 - 4 Jul 2020

Cited by 56 | Viewed by 8799

Abstract

With the aggravation of the energy crisis and environmental problems, biomass resource, as a renewable carbon resource, has received great attention. Catalytic fast pyrolysis (CFP) is a promising technology, which can convert solid biomass into high value liquid fuel, bio-char and syngas. Catalyst [...] Read more.

With the aggravation of the energy crisis and environmental problems, biomass resource, as a renewable carbon resource, has received great attention. Catalytic fast pyrolysis (CFP) is a promising technology, which can convert solid biomass into high value liquid fuel, bio-char and syngas. Catalyst plays a vital role in the rapid pyrolysis, which can increase the yield and selectivity of aromatics and other products in bio-oil. In this paper, the traditional zeolite catalysts and metal modified zeolite catalysts used in CFP are summarized. The influence of the catalysts on the yield and selectivity of the product obtained from pyrolysis was discussed. The deactivation and regeneration of the catalyst were discussed. Catalytic co-pyrolysis (CCP) and microwave-assisted pyrolysis (MAP) are new technologies developed in traditional pyrolysis technology. CCP improves the problem of hydrogen deficiency in the biomass pyrolysis process and raises the yield and character of pyrolysis products, through the co-feeding of biomass and hydrogen-rich substances. The pyrolysis reactions of biomass and polymers (plastics and waste tires) in CCP were reviewed to obtain the influence of co-pyrolysis on composition and selectivity of pyrolysis products. The catalytic mechanism of the catalyst in CCP and the reaction path of the product are described, which is very important to improve the understanding of co-pyrolysis technology. In addition, the effects of biomass pretreatment, microwave adsorbent, catalyst and other reaction conditions on the pyrolysis products of MAP were reviewed, and the application of MAP in the preparation of high value-added biofuels, activated carbon and syngas was introduced. Full article

(This article belongs to the Special Issue Perspectives in Catalytic Fast Pyrolysis, Catalytic Hydrodeoxygenation, and Catalytic Fast Hydropyrolysis)

Journal Menu

Journal Browser

Perspectives in Catalytic Fast Pyrolysis, Catalytic Hydrodeoxygenation, and Catalytic Fast Hydropyrolysis

Share This Special Issue

Special Issue Editor

Special Issue Information

Keywords

Benefits of Publishing in a Special Issue

Related Special Issue

Published Papers (16 papers)

Research

Review

Further Information

Guidelines

MDPI Initiatives

Follow MDPI