Article
Chemistry, Physical
Jiawei Hu, Hilde Poelman, Stavros-Alexandros Theofanidis, Jonas J. Joos, Christophe Detavernier, Dirk Poelman, Wei Wei, Vladimir V. Galvita
Summary: CCLHGD is a new hot gas desulfurization method that utilizes alternating sulfuration and regeneration processes to remove H2S. Fe2O3 is gradually converted into iron sulfides by H2S, and it can be fully regenerated to iron oxides by CO2. This work provides an efficient chemical looping scheme for H2S removal and offers new opportunities for hot gas desulfurization.
APPLIED CATALYSIS B-ENVIRONMENTAL
(2023)
Article
Energy & Fuels
K. Y. Kwong, A. R. P. Harrison, J. C. Gebers, J. S. Dennis, E. J. Marek
Summary: This research investigates the combustion of biomass char in fluidized beds using various particulate solids as either inert materials or oxygen carriers. The study finds that CuO and SrFeO3-delta release gaseous oxygen by thermal decomposition, while Fe2O3 competes with the combustion of biomass char for oxygen. The combustion time in the bed of Fe2O3 particles is similar to that in the inert bed of SiO2, despite the active role of iron oxide in the process.
Article
Energy & Fuels
K. Y. Kwong, A. R. P. Harrison, J. C. Gebers, J. S. Dennis, E. J. Marek
Summary: This research focuses on the combustion of biomass char in fluidized beds, finding that the oxygen carriers CuO and SrFeO3-δ have the best performance in accelerating combustion rate.
Article
Energy & Fuels
Eduardo Arango Durango, Carmen R. Forero, Francisco J. Velasco-Sarria
Summary: Chemical looping combustion (CLC) is an energy efficient technology for capturing CO2 emissions in combustion processes, using solid oxygen carriers to transfer oxygen from air to fuel. Research has shown that a manganese mineral may be a promising low-cost oxygen carrier material for CLC applications.
Article
Chemistry, Physical
Jun Zhao, Yingwei Xiong, Zhihua Gao, Fengyan Fu, Lili Niu, Min Jin
Summary: Moderate temperature chemical looping processes can effectively mitigate the sintering and deterioration of oxygen carriers. In this study, co-doping Fe2O3 with La and Sm in CeO2 improved oxygen-ion conduction and increased oxygen capacity, resulting in enhanced CO2-splitting performance at 650 degrees C.
SUSTAINABLE ENERGY & FUELS
(2022)
Review
Chemistry, Applied
Mogahid Osman, Mohammed N. Khan, Abdelghafour Zaabout, Schalk Cloete, Shahriar Amini
Summary: Pressurized operation plays a crucial role in chemical looping systems and has been studied extensively. The impact of pressure on reaction kinetics is less significant than previously believed. Further research is needed to determine the most effective reactor configurations and techno-economic assessments for pressurized chemical looping processes.
FUEL PROCESSING TECHNOLOGY
(2021)
Article
Chemistry, Applied
Dewang Zeng, Tong Liu, Yanzhi Li, Zhenwu Zhang, Yang Zhang, Rui Xiao
Summary: In this study, one-dimensional nano-fiber Fe2O3/ZrO2 was used as a catalyst for chemical looping water gas shift to produce hydrogen, and the effect of particle size on the redox chemistry was studied. The results showed that the reactivity and stability of nano-fibers were size dependent. Increasing the particle size significantly enhanced stability but reduced activity. Particularly, the nano-fiber with a diameter of about 99 nm exhibited high hydrogen yield and stable performance over 60 redox cycles at 750 degrees C. Mechanism study revealed that the small size could enhance reduction depth in the initial cycles for high hydrogen production, but caused severe sintering after repetitive cycles. Therefore, selecting an optimal size (99 nm in diameter) is crucial for simultaneously ensuring high reactivity and stability. We anticipate that the size effect on redox chemistry will have extensive implications for the development of efficient oxygen carriers.
FUEL PROCESSING TECHNOLOGY
(2023)
Article
Chemistry, Physical
Qiming Tang, Yuxi Ma, Kevin Huang
Summary: FeOx is commonly used in CLH reactors and SOIARBs due to its abundance, low cost, and high oxygen content. However, the reduction kinetics of FeOx limits the performance of Fe/FeOx chemical looping cycles. This study investigates the kinetics of Fe3O4 reduction and highlights the crucial role of ZrO2 in preventing Fe particle sintering and ensuring stable operation of chemical looping cycles.
ACS APPLIED ENERGY MATERIALS
(2021)
Article
Chemistry, Physical
Hessamodin Nourbakhsh, Yasin Khani, Akbar Zamaniyan, Farzad Bahadoran
Summary: CeZr0.5GdO4 spinel particles are introduced as oxygen carriers for methane reforming and decomposition, showing high activity and stability for continuous production of hydrogen and carbon monoxide with minimal CO2 and H2O emissions.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2022)
Article
Engineering, Environmental
Xiaofeng Jiang, Hao Zheng, Yazhou Wu, Zhuo Cheng, Liang Zeng, Liang-Shih Fan
Summary: A novel chemical looping preferential oxidation (CL-PROX) process has been proposed and demonstrated for efficient elimination of trace level CO from H-2-rich streams. The process shows excellent CO removal performance and high H-2 recovery using a ceria-supported gamma-Fe2O3 oxygen carrier.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Engineering, Chemical
William Benincosa, Jarrett Riley, Ranjani Siriwardane, Hanjing Tian, James Poston
Summary: In this study, CuFeMnO4 oxygen carrier was characterized using various techniques, and a reaction model was selected to describe the chemical looping combustion reactions. The intrinsic reaction rate parameters obtained can aid in reactor design for scale-up, and the combined model showed the best correlation with experimental data.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2021)
Article
Energy & Fuels
Shuoxin Zhang, Yuchuan Feng, Xin Guo
Summary: The study found that copper doping enhanced the activities of iron-based oxygen carriers, but excessive copper would reduce their reactivity due to melting and agglomeration. Hydrogen temperature-programmed reduction (H-2-TPR) analysis, fixed-bed experiments, and density functional theory (DFT) calculations confirmed that Cu promoted the deep reduction of Fe2O3. The oxygen carrier doped with 1 wt % CuO was the most suitable material for CLH, with the highest hydrogen yield sustained at a high and stable level in multiple redox cycles.
Article
Thermodynamics
Yang Wang, Zhenshan Li
Summary: The redox kinetics of oxygen carrier in chemical looping plays a crucial role in material preparation, reactor design, and process demonstration. This study presents a DFT-based microkinetic rate equation theory to predict the heterogeneous kinetics of Fe2O3 reduction by CO in chemical looping. By combining density functional theory (DFT) calculations with transition state theory (TST) and bulk diffusion consideration, a rate equation is developed to bridge the gap between elementary surface reactions and grain conversion. Experimental data validation shows the accuracy and effectiveness of the developed theory in predicting the redox kinetics of oxygen carriers.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Energy & Fuels
Yewen Tan, Jarrett Riley, Dennis Lu, Ranjani Siriwardane, Robin Hughes
Summary: The reduction and oxidation kinetics of a CuFeMnAlO4+δ oxygen carrier for methane were investigated using atmospheric and pressurized TGAs, with important parameters such as temperature, particle size distribution, and partial pressures of reactants evaluated. The results showed that the reduction of the oxygen carrier was not affected by particle size distribution, and the temperature's effect on the reduction diminished above 750°C. The reaction time approached an asymptotic limit as methane partial pressure increased. The oxidation rate of the oxygen carrier increased with higher oxygen concentration, especially when the concentration was below 7.5%.
Article
Energy & Fuels
Yewen Tan, Jarrett Riley, Dennis Lu, Ranjani Siriwardane, Robin Hughes
Summary: The reduction and oxidation kinetics of a CuFeMnAlO4+delta oxygen carrier for methane were studied. Important parameters such as temperature, particle size distribution, and partial pressures of reactants were evaluated. Results showed that particle size distribution did not affect the reduction of the oxygen carrier, and the temperature had less effect on the reduction at temperatures above 750 degrees C. The rate of oxidation increased with increasing oxygen concentration, and the effect was more noticeable at oxygen concentrations below 7.5%. Additionally, a shrinking sphere model was used to model the test data, and the limitations of the pressurized TGA were discussed.
Article
Engineering, Chemical
Andrea Coletto, Pietro Poesio
Summary: Experiments and simulations were conducted to study the air volume fraction and hold-up in a bubble channel reactor. A new signal processing method was proposed to avoid the loss of bubble residence time. The results were in agreement with previous studies and a bubble-scale model was developed to explain the relationship between hold-up and air superficial velocity.
CHEMICAL ENGINEERING RESEARCH & DESIGN
(2024)