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Effect of CoMo metal loading on H2 and CNTs production from biogas by integrative process
(2022-12-19)
Aieamsam-Aung, Pichawee
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Nantapong, Paveenuch
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Rattanaamonkulchai, Raminda
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Kludpantanapan, Thunyathon
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Srifa, Atthapon
Effect of CoMo metal loading to MgO (1, 5, 30 and 50 wt%) on conversion of biogas by an integrative process was investigated at 900 °C under atmospheric pressure. The integrative process combines the direct methanation of CO<inf>2</inf> in biogas and the CH<inf>4</inf> decomposition to upgrade biogas to CH<inf>4</inf> and decompose to hydrogen and carbon nanotubes. Methane dissociative reaction is governed by the concentration of active metals on the catalyst surface, while DRM reaction is suppressed. The 30 wt%CoMo catalyst shows the optimal loading for production of high-purity H<inf>2</inf> (>90v/v%) and high yield of MWCNTs (2.33 gCNT/gCat-h) with 100%CO<inf>2</inf> conversion and 95%CH<inf>4</inf> conversion. Meanwhile, 1 wt%CoMo catalyst provided the single-walled CNTs with diameter of 2.5 nm, high surface area of 165 m2/g and high graphitization of I<inf>G</inf>/I<inf>D</inf> = 6.14.
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Catalytic conversion of bioethanol to value-added chemicals and fuels: A review
(2022-03-01)
Xiang, Huan
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Xin, Ruojia
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Prasongthum, Natthawan
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Natewong, Paweesuda
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Sooknoi, Tawan
Bioethanol produced via valorisation of renewable biomass is of great interest to many industries. The increased availability and decreased cost of bioethanol make it a promising platform molecule to produce a wide range of value-added chemicals and fuels via the catalytic conversions. This paper provides a comprehensive review of catalytic conversions of bioethanol to a variety of chemicals/fuels such as hydrogen, C<inf>2</inf>–C<inf>4</inf> olefins, gasoline and small oxygenates. Specifically, the focus was placed on the relationship between the catalyst property (such as pore structure, acidity, active metal sites, and catalyst supports) and the catalytic performance (including catalyst activity and stability), as well as the reaction mechanisms involved. Future research avenues on the catalyst design for improving catalytic valorisation of bioethanol are also discussed.
3
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Catalytic Hydrotreating of Crude Pongamia pinnata Oil to Bio-Hydrogenated Diesel over Sulfided NiMo Catalyst
(2022-02-01)
Plaola, Yuwadee
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Leangsiri, Wanwipa
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Pongsiriyakul, Kanokthip
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Kiatkittipong, Worapon
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Srifa, Atthapon
This work studied the catalytic activity and stability of Ni-MoS2 supported on γ-Al2O3, SiO2, and TiO2 toward deoxygenation of different feedstocks, i.e., crude Pongamia pinnata oil (PPO) and refined palm olein (RPO). PPO was used as a renewable feedstock for bio-hydrogenated diesel production via catalytic hydrotreating under a temperature of 330 °C, H2 pressure of 50 bar, WHSV of 1.5 h−1, and H2/oil (v/v) of 1000 cm3/cm3 under continuous operation. The oil yield from a Soxhlet extraction of PPO was up to 26 wt.% on a dry basis, mainly consisting of C18 fatty acids. The catalytic activity in terms of conversion and diesel yield was in the same trend as increasing in the order of NiMo/γ-Al2O3 > NiMo/TiO2 > NiMo/SiO2. The hydrodeoxygenation (HDO) activity was more favorable over the sulfided NiMo supported on γ-Al2O3 and TiO2, while a high DCO was observed over the sulfided NiMo/SiO2 catalyst, which related to the properties of the support material and the intensity of metal–support interaction. The deactivation of NiMo/SiO2 and NiMo/TiO2 occurred in a short period, due to the phosphorus and alkali impurities in PPO which were not found in the case of RPO. NiMo/γ-Al2O3 exhibited the high resistance of impure feedstock with excellent stabil-ity. This indicates that the catalytic performance is influenced by the purity of the feedstock as well as the characteristics of the catalysts.
2
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Effective Cu/Re promoted Ni-supported γ-Al2O3 catalyst for upgrading algae bio-crude oil produced by hydrothermal liquefaction
(2021-06-01)
Pongsiriyakul, Kanokthip
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Kiatkittipong, Worapon
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Adhikari, Sushil
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Lim, Jun Wei
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Lam, Su Shiung
Catalytic hydrotreating of algae bio-crude oil from hydrothermal liquefaction (HTL) of Nannochloropsis sp. was performed. Different Ni-based catalysts, including Ni/γ-Al<inf>2</inf>O<inf>3</inf>, Ni-Cu/γ-Al<inf>2</inf>O<inf>3,</inf> Ni-Re/γ-Al<inf>2</inf>O<inf>3,</inf> and Ni-Cu-Re/γ-Al<inf>2</inf>O<inf>3,</inf> (10%Ni, 5%Cu, 2.5%Re) were used in upgrading of the bio-crude oil. Most catalytic systems could effectively eliminate S and decrease the N and O contents, and enhance more than 20% improvement in the higher heating value (HHV) of the bio-oil (34 to 41–45 MJ/kg). Introducing only Cu could enhance the C[dbnd]O hydrogenation resulting in higher aromatic and alcohol compounds. While the addition of Re is effective for hydrodeoxygenation, it lowers denitrogenation due to amination reaction. Ni-Cu-Re/γ-Al<inf>2</inf>O<inf>3</inf> ternary alloy offered the best results on the overall performance, achieving the highest upgraded bio-oil yield of 58 wt% and the highest energy recovery in the upgrading process (ER<inf>upgrade</inf>) of 64.6%. As ER in HTL process (ER<inf>HTL</inf>) was ca. 71.8%, the overall ER (ER<inf>overall</inf>) from algae biomass to upgraded bio-oil of 46.4% can be achieved for Ni-Cu-Re/γ-Al<inf>2</inf>O<inf>3</inf> catalyst. Carbon efficiency approx. 47.7% can be attained as the carbon in the algae biomass feedstock was retained in the upgraded bio-oil. In addition, reaction pathways for the formation of different hydrotreated products catalyzed by mono-, bi-, and tri- metallic Ni-Cu-Re have been proposed.
1
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A Well-Defined Core–Shell-Structured Capsule Catalyst for Direct Conversion of CO2 into Liquefied Petroleum Gas
(2020-04-21)
Li, Hangjie
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Zhang, Peipei
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Guo, Lisheng
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He, Yingluo
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Zeng, Yan
A Pd/SiO<inf>2</inf>@S1@H-ZSM-5 capsule catalyst (Pd/SiO<inf>2</inf>–SZ) is fabricated through a dual-layer crystal growth method with an auxiliary hydrothermal reaction. The catalyst exhibits excellent selectivity to liquefied petroleum gas (LPG) in CO<inf>2</inf> hydrogenation reactions, which is attributed to the tandem reactions of methanol synthesis on the Pd/SiO<inf>2</inf> core catalyst and methanol dehydration to hydrocarbons on the H-ZSM-5 shell. The Pd/SiO<inf>2</inf>–SZ capsule catalyst has a similar mesoporous structure, narrow range of Pd particles size distribution, and consistent reduction characteristics to the Pd/SiO<inf>2</inf> core catalyst. It maintains the physical and chemical properties of the core catalyst throughout the H-ZSM-5 shell synthesis process. Energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy results reveal that the H-ZSM-5 zeolite shell completely encapsulates the Pd/SiO<inf>2</inf> core catalyst. Compared with the crushed capsule catalyst (Pd/SiO<inf>2</inf>–SZP), the well-defined-structured Pd/SiO<inf>2</inf>–SZ catalyst has a much higher LPG selectivity of 33.6 %, owing to the well-matched reactions at the Pd/SiO<inf>2</inf> core and H-ZSM-5 shell.
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