Article
Chemistry, Physical
Niko Heikkinen, Laura Keskivali, Patrik Eskelinen, Matti Reinikainen, Matti Putkonen
Summary: ALD was used to prepare a thin alumina layer on Fischer-Tropsch catalysts, leading to increased activity without significant loss of selectivity. The stabilization of cobalt particles and nanoscale porosity of the overcoating were key factors in enhancing activity. Thermal annealing was essential in preparing the ALD overcoated catalyst.
Article
Chemistry, Physical
Roya Dehghan-Niri, Nikolaos E. Tsakoumis, Alexey Voronov, Anders Holmen, Randi Holmestad, Per-Erik Vullum, Oyvind Borg, Erling Rytter, Magnus Ronning, John C. Walmsley
Summary: The structure of a rhenium promoted Fischer-Tropsch cobalt catalyst supported on gamma-Al2O3 was investigated using TEM and XRD. The size and morphology of cobalt aggregates, particles, and crystallites were analyzed in different states. This study provides important information for understanding the relationship between catalyst structure and performance.
Article
Chemistry, Physical
Shupeng Guo, Congcong Niu, Zhongyi Ma, Jungang Wang, Bo Hou, Litao Jia, Debao Li
Summary: Introducing Ba and CN species into Co/Al2O3 catalyst can enhance the electron density on the cobalt surface, which improves the C-5(+) selectivity and C-3 o/p ratio, leading to enhanced catalytic performance in Fischer-Tropsch synthesis reaction.
Article
Energy & Fuels
Shupeng Guo, Congcong Niu, Zhongyi Ma, Jungang Wang, Bo Hou, Litao Jia, Debao Li
Summary: N-doped carbon materials are being studied as a promising support for catalytic performance in Fischer-Tropsch synthesis, with efforts to overcome complex preparation methods. This study introduces a simple and harmless approach to prepare CN-modified Co/Al2O3 catalyst, showing improved reducibility and electron density on cobalt surface, leading to enhanced selectivity and TOF. This research provides a new avenue for obtaining high activity and selectivity catalysts.
Article
Energy & Fuels
Shupeng Guo, Zhongyi Ma, Jungang Wang, Bo Hou, Litao Jia, Baojun Wang, Debao Li
Summary: The synergistic promotion effect of Ru and Ba in Co/Al2O3 catalyst achieved higher CO conversion and lower CH4 selectivity, compared to unmodified or single additive modified catalyst. The influences of other alkali earth metal additives were also similar to that of Ba in promoting FTS reaction on Co-Ru catalysts.
Article
Chemistry, Physical
Xinyan Ai, Yuhua Zhang, Shuai Lyu, Chengchao Liu, Yanxi Zhao, Jinlin Li
Summary: To investigate the impact of gamma-alumina pore size on the efficiency of Co/Al2O3 catalysts in Fischer-Tropsch synthesis, ordered mesoporous alumina samples with different pore sizes were synthesized and Co/OMA catalysts were prepared. Characterization experiments were conducted and the relationship between catalyst structure and FTS performance was analyzed. The TOF and C5+ selectivity of the catalysts increased with increasing OMA pore size, while CH4 selectivity decreased. The particle size of Co3O4 in the catalysts was highly dependent on the OMA pore size, which was a crucial factor affecting catalyst performance.
Article
Chemistry, Physical
Somayeh Mansouri, Seyyed Hossein Zohdi, Hossein Atashi, Maliheh Ghofran Pakdel, Ali Akbar Mirzaei
Summary: The size of catalysts has no impact on the type of deactivation model. Smaller catalysts have a smaller deactivation constant and higher long-term stability. Larger catalyst sizes tend to accumulate carbon and heavy hydrocarbon fouling, leading to decreased specific surface area and lower catalytic activity.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2022)
Article
Chemistry, Multidisciplinary
Nabil Majd Alawi, Firas Khaleel AL-Zuhairi, Hoang M. Nguyen, Hassan H. Al-Mohammedawi, Jamal M. Ali
Summary: This study investigates the kinetics of the Fischer-Tropsch process synthesis using feedstocks from biogas. The results show that a simple model can accurately describe the reaction kinetics under different working conditions.
Article
Chemistry, Physical
Roman E. Yakovenko, Grigory B. Narochnyi, Ivan N. Zubkov, Ekaterina A. Bozhenko, Yash V. Kataria, Roman D. Svetogorov, Alexander P. Savost'yanov
Summary: This article presents a simple method for producing high-octane gasoline from CO and H-2 using a Co-Al2O3/SiO2/HZSM-5/Al2O3 hybrid catalyst. By adjusting the pressure and temperature, the content of branched hydrocarbons can be increased. The experimental batch of gasoline fraction produced under the optimized process parameters has an octane number of 78.5 units.
Article
Engineering, Chemical
Imaad Davies, Klaus P. Moller
Summary: The kinetics of n-paraffin and 1-olefin formation in the Fischer-Tropsch reaction system are equilibrium-limited, allowing for an effective description of product distribution and observed reaction behavior trends. The model preserves the polymerization character of the reaction and successfully describes the dominant trends in product distribution as a function of CO conversion, temperature, and pressure.
CHEMICAL ENGINEERING SCIENCE
(2021)
Article
Chemistry, Physical
Tobias F. Kimpel, Jin-Xun Liu, Wei Chen, Robert Pestman, Emiel J. M. Hensen
Summary: Through IR spectroscopy and DFT calculations, it has been discovered that in the Fischer-Tropsch reaction, Mn promotes a silica-supported Co catalyst with a MnO layer covering the Co surface, activating adsorbed CO through reaction with an oxygen vacancy. This results in higher activity, higher CHx coverage, increased C5+ selectivity, and decreased CH4 selectivity. Increasing pressure amplifies the selectivity differences. However, above around 4 bar, the addition of Mn decreases C5+ selectivity, possibly due to its promotion of C-O bond dissociation but not chain growth. Migration of formed monomers for chain growth on the Co surface may be hindered by high CO coverage, especially at high pressure.
JOURNAL OF CATALYSIS
(2023)
Article
Chemistry, Physical
Jose Antonio Diaz-Lopez, Jordi Guilera, Marti Biset-Peiro, Dan Enache, Gordon Kelly, Teresa Andreu
Summary: The technical feasibility of passivating a Co/gamma-Al2O3 catalyst using atomic layer deposition (ALD) to reduce deactivation rate during Fischer-Tropsch synthesis (FTS) was explored in this study. The results showed that 3 to 6 ALD cycles effectively reduced deactivation of the catalyst, while 10 cycles caused blockage of the active phase and a decrease in catalytic activity. This research demonstrates the potential of ALD as a method to improve catalyst stability in FTS processes.
Article
Engineering, Chemical
Mohammad Hosein, Eghbal Ahmadi, Amir Mosayebi
Summary: Three different models were developed to predict the behavior of Fischer-Tropsch synthesis over Co-Ni/Al2O3 catalyst, with the GA-Fuzzy model showing higher performance and interpretability, while the kinetic model provided a more realistic representation of reactor behavior.
JOURNAL OF THE TAIWAN INSTITUTE OF CHEMICAL ENGINEERS
(2021)
Article
Chemistry, Applied
Sania Saheli, Ali Reza Rezvani, Azadeh Arabshahi, Michal Dusek, Erika Samolova, Marketa Jarosova
Summary: The preparation methods of two new catalysts for Fischer-Tropsch synthesis were studied, with the catalyst prepared via thermal decomposition showing higher activity due to its smaller particle size, better dispersion, and higher surface area. The catalyst obtained by impregnation method exhibited lower activity compared to the one prepared by thermal decomposition.
APPLIED ORGANOMETALLIC CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Thitiwut Sukprom, Pooripong Somchuea, Sarannuch Sringam, Thongthai Witoon, Metta Chareonpanich, Pawin Iamprasertkun, Kajornsak Faungnawakij, Gunther Rupprechter, Anusorn Seubsai
Summary: This study investigated the direct conversion of methane (CH4) to value-added hydrocarbons (C2+) using a hybrid catalyst. The hybrid catalyst consisted of Ni/Al2O3 as the first catalyst layer to convert CH4 to carbon monoxide and K-Co/Al2O3 as the second catalyst layer to convert carbon monoxide to C2+. The hybrid catalyst exhibited effective performance at a relatively low temperature of 490 degrees C, compared to other catalysts used in methane oxidative coupling reactions. The study explored the effects of different operating conditions and found that the highest C2+ yield of 4.3% was achieved at a reactor temperature of 490 degrees C. The addition of K promoter played a crucial role in enhancing C2+ formation. The proposed mechanism for the reaction using the hybrid catalyst was described, and the stability of the catalyst was observed to be excellent during a 24-hour time-on-stream test.
REACTION CHEMISTRY & ENGINEERING
(2023)
Article
Energy & Fuels
V. T. Cheang, R. A. Hedderwick, C. McGregor
Article
Energy & Fuels
S. Clark, C. McGregor, J. L. Van Niekerk
Summary: With the load-shedding problem and increasing fuel costs, replacing diesel fuel with natural gas presents a potential solution for cost reduction in Eskom's peaking plants. Due to the sourcing issues of natural gas, options of introducing liquefied natural gas or liquefied petroleum gas are being considered. While the high capital cost of liquefied natural gas has led to delays, using liquefied petroleum gas can be implemented in a short time-frame and is expected to significantly lower fuel costs.
JOURNAL OF ENERGY IN SOUTHERN AFRICA
(2022)
Article
Energy & Fuels
L. G. Redelinghuys, C. McGregor
Summary: This study examines the application of a Carnot battery in a conventional parabolic trough concentrating solar power plant. The results show that under certain conditions, imported renewable energy is stored at the expense of solar thermal energy, leading to unnecessary overcharging of the storage. The study also finds that smaller-sized parabolic trough solar fields can reduce and delay solar thermal curtailment caused by heater integration.
JOURNAL OF ENERGY STORAGE
(2023)
Article
Energy & Fuels
Francois Rozon, Craig McGregor, Michael Owen
Summary: Published forecasts underestimate the growth of renewable energy and potential cost reductions, leading to increased uncertainty in investment decisions and slower progress. This research demonstrates that data-driven approaches can improve capacity and cost forecasts of solar, wind, and battery storage technologies, providing more accurate outlooks for the future.
Article
Energy & Fuels
S. Clark, J. van Niekerk, J. Petrie, C. McGregor
Summary: This paper explores the role of natural gas in supporting the transition to renewable energy in South Africa and identifies the major challenge of providing sufficient gas storage facilities.
JOURNAL OF ENERGY IN SOUTHERN AFRICA
(2022)
Proceedings Paper
Energy & Fuels
Tristan Mckechnie, Craig McGregor, Gerhard Venter
Summary: In this paper, a new methodology is developed for optimizing HelioPodTM field layouts. Inspired by pattern-based optimization techniques, the methodology aims to replicate the benefits of the radial stagger layout for pod fields. It is shown to outperform an existing heuristic design method.
SOLARPACES 2020 - 26TH INTERNATIONAL CONFERENCE ON CONCENTRATING SOLAR POWER AND CHEMICAL ENERGY SYSTEMS
(2022)
Proceedings Paper
Green & Sustainable Science & Technology
Tristan Mckechnie, Craig McGregor, Gerhard Venter
PROCEEDINGS OF THE ASME 2020 14TH INTERNATIONAL CONFERENCE ON ENERGY SUSTAINABILITY (ES2020)
(2020)
Article
Computer Science, Interdisciplinary Applications
S Kauchali, C McGregor, D Hildebrandt
COMPUTERS & CHEMICAL ENGINEERING
(2000)
Article
Engineering, Chemical
M Tapp, S Kauchali, B Hausberger, C McGregor, D Hildebrandt, D Glasser
CHEMICAL ENGINEERING SCIENCE
(2003)
