Article
Chemistry, Physical
Weidong Sun, Guofeng Zhao, Ya Gao, Jiaqi Si, Ye Liu, Yong Lu
Summary: This study reported an efficient catalyst obtained by decorating an oxygen carrier FeMnO3 with Na2WO4, achieving high CH4 conversion rate and C-2-C-3 selectivity with good cycling performance at 800 degrees Celsius, demonstrating great potential for application in the CL-OCM process.
APPLIED CATALYSIS B-ENVIRONMENTAL
(2022)
Article
Chemistry, Applied
Sergio Damasceno, Fabiane J. Trindade, Fabio C. Fonseca, Daniel Z. de Florio, Andre S. Ferlauto
Summary: This study provides a mini-review on the oxidative coupling of methane (OCM) process based on the chemical looping (CL) concept, where methane and oxygen are fed separately in two cyclic steps using a metal oxide catalyst as the oxygen source. CL shows promise in improving selectivity for methane conversion by using lattice oxygen species and avoiding undesired combustion reactions triggered by molecular oxygen.
FUEL PROCESSING TECHNOLOGY
(2022)
Article
Energy & Fuels
Shican Jiang, Weixiao Ding, Kun Zhao, Zhen Huang, Guoqiang Wei, Yanyan Feng, Yijv Lv, Fang He
Summary: This study successfully utilized Na-doped LaMnO3 as redox catalysts to convert methane into C-2 products, achieving higher performance in oxidative coupling reaction. The incorporation of Na enhanced the redox properties of the catalyst, promoting the formation of C-2 hydrocarbons, with 019Na-LaMnO3 demonstrating the best results among all samples.
Article
Chemistry, Applied
Dewang Zeng, Chen Wang, Tong Liu, Wentao Ou, Rui Xiao
Summary: Doping TiO2 can enhance the performance of chemical looping methane oxidative coupling, increasing the conversion of CH4 without significantly decreasing the selectivity for C-2 products.
FUEL PROCESSING TECHNOLOGY
(2022)
Article
Chemistry, Applied
Ju Huang, Kun Zhao, Shican Jiang, Shunshun Kang, Yan Lin, Zhen Huang, Anqing Zheng, Zengli Zhao
Summary: A novel composite oxide carrier doped by hetematoms was developed for the selective and stable production of C-2(+) hydrocarbons from methane in chemical looping oxidative coupling. Doping with Na improved the surface O- and Mn2+/Mn3+ species content, leading to higher C-2(+) selectivity and yield. Co-doping with W stabilized surface Na species, resulting in stable performance.
FUEL PROCESSING TECHNOLOGY
(2022)
Article
Energy & Fuels
Sonu Kumar, Pinak Mohapatra, Rushikesh K. Joshi, Matthew Warburton, Liang-Shih Fan
Summary: We propose a new low-temperature chemical looping combustion scheme for natural gas conversion into CO2 and NOx purification. The process utilizes NiO/ZrO2 as the oxygen carrier and operates at temperatures close to the flue gas temperature of 400-500 degrees C. Thermodynamic studies show that the presence of CO2 does not significantly affect NOx purification performance. Comparative analyses indicate improvements in exergy efficiency and effective thermal efficiency compared to conventional NOx selective catalytic reduction (SCR) processes.
Article
Energy & Fuels
Yuchuan Feng, Nana Wang, Xin Guo
Summary: DFT calculations were used to explore the reaction mechanism of methane conversion over Ca2Fe2O5 oxygen carrier in chemical looping hydrogen production. The study found that while H-2 generation is difficult on the surface of Ca2Fe2O5, CO formation is prone to occur and the oxygen diffusion needs to overcome a high energy barrier. The activation of CH4 was identified as the dominant rate-determining step, suggesting the need for promoters to enhance the CH4 reactivity of Ca2Fe2O5.
Article
Engineering, Environmental
Sunkyu Kim, Leelavathi Annamalai, Raul F. Lobo
Summary: The combination of methane dehydroaromatization (MDA) and chemical looping (CL) combustion of hydrogen can overcome the thermodynamic constraints limiting conversion. The development of selective hydrogen-oxidation oxygen carriers in the CL is crucial for improving MDA performance. A novel oxygen carrier, silica-encapsulated Fe2O3, demonstrated high overall methane conversion and aromatics yield in a recirculating system. The silica layer prevented aromatics diffusion and promoted hydrogen transport and oxidation, while close physical contact between iron oxide particles and silica facilitated hydrogen conversion without full depletion of iron oxides.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Energy & Fuels
Ranjani Siriwardane, Jarrett Riley, William Benincosa, Samuel Bayham, Michael Bobek, Douglas Straub, Justin Weber
Summary: The Copper-Ferri-Manganese-Aluminate spinel oxygen carrier developed at NETL has shown promising results for chemical looping combustion with methane, with high attrition resistance and oxygen transfer capacity. The carrier prepared at a commercial manufacturing facility displayed similar performance to lab scale preparations, demonstrating satisfactory methane conversion and high particle durability during testing.
Article
Chemistry, Physical
Yongcheng Cai, Chenxuanzi Wang, Mingxuan Zhong, Zewei Zhang, Bo Xiao, Tingting Xu, Xun Wang
Summary: In this study, Ca2Fe2O5 oxygen carrier was prepared by the sol-gel method and its reduction and oxidation kinetics were evaluated in H2 and CO2 atmospheres, respectively. The reduction process of Ca2Fe2O5 followed a random nucleation and growth model, while the oxidation process followed a zero-order contraction model. The kinetics analysis showed that both the reduction and oxidation processes of Ca2Fe2O5 were one-step reactions.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2023)
Article
Chemistry, Applied
Xinfei Chen, Luwen Wang, Yan Lin, Tao Zeng, Zhen Huang, Yongqi Zhang, Ya Xiong, Jun Li, Lisheng Deng, Hongyu Huang
Summary: Ca2Fe2O5/Zr0.5Ce0.5O2 exhibited excellent reactivity in chemical looping dry reforming of methane. The migration of lattice oxygen during redox process was explored, revealing the release of lattice oxygen, structural change, and crystalline phase transformation. The understanding of oxygen migration provides a reference for improving the cyclic stability of Ca2Fe2O5/Zr0.5Ce0.5O2.
FUEL PROCESSING TECHNOLOGY
(2023)
Article
Chemistry, Applied
Shiwei Ma, Fang Cheng, Junguang Meng, Huijun Ge, Ping Lu, Tao Song
Summary: The feasibility of using Ni-enhanced red mud in chemical looping steam methane reforming (CL-SMR) was evaluated. It was found that the Ni-enhanced red mud displayed desirable reactivity and cyclic stability, with CO selectivity reaching 94.1% and H-2/CO ratio of 2.01 at the most suitable temperature of 900 C. The Ni species effectively activated the C-H bond of methane and facilitated the transfer of lattice oxygen.
FUEL PROCESSING TECHNOLOGY
(2022)
Article
Chemistry, Applied
Li Yang, Dan Zhu, Xin Wu, Chen Song, Caifu Li, Fang Liu, Zhengchang Song
Summary: Chemical looping combustion relies on high performance oxygen carriers (OCs). Iron-based OCs have excellent overall properties, but the disadvantage of low reduction reactivity limits their application prospects. Clarification of oxygen transfer pathways and bulk phase properties is essential to improve oxygen transfer rates and increase the reactivity of OCs.
FUEL PROCESSING TECHNOLOGY
(2023)
Article
Engineering, Environmental
Fangjun Wang, Shiyi Chen, Shubo Chen, Jun Du, Lunbo Duan, Wenguo Xiang
Summary: This study developed a series of Ni and Co doped CeO2/La2Ni2-xCoxO6 double perovskite composite oxygen carriers for chemical looping steam methane reforming (CL-SMR), achieving the co-production of syngas and hydrogen. The introduction of Co increased surface active sites, accelerating the activation of CH4, while the addition of Ni provided oxygen vacancies to promote oxygen migration. The optimal substitution ratios were 0.6 for cobalt and 1.4 for nickel. The CeO2/La2Ni1.4Co0.6O6 sample showed excellent syngas selectivity (95%) and high methane conversion (86%) at 850 degrees Celsius, with close to 100% hydrogen concentrations in the steam oxidation stage. DFT calculations demonstrated the strongly exothermic partial oxidation of methane, and the CeO2-loaded double perovskite was more conducive to CH4 activation and prevented carbon deposition. The Ni-Co synergistic effect greatly promoted the partial oxidation of methane, and the reduced metals combined with oxygen vacancies provided active stable points for water vapor cracking to generate high-purity hydrogen.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Engineering, Environmental
Mingze Su, Haibo Zhao, Xiaoyu Wang
Summary: This study explores the oxygen uncoupling kinetics of CuO oxygen carrier using a multi-scale methodology. The results show that gas diffusion, especially in the sample layer, plays a significant role in the conversion process of CuO samples. Additionally, the physical structure of CuO particles, specifically the grain size, has an important effect on the oxygen uncoupling rate, with an optimal size of 245 nm.
CHEMICAL ENGINEERING JOURNAL
(2022)
Article
Energy & Fuels
Anuj Joshi, Rushikesh K. Joshi, Eric Falascino, Tanay A. Jawdekar, Shekhar G. Shinde, Deven Baser, Shalin Patil, Liang-Shih Fan
Summary: The rising demand for chemicals and concerns about climate change have led to efforts to convert diverse domestic sources into valuable products in a decarbonized manner. Lignocellulosic biomass is being seen as a sustainable alternative to fossil fuels, but challenges in handling feed variability and processing char and tar contents have hindered its commercial deployment. The Ohio State University has developed a chemical looping-based biomass-to-syngas technology, utilizing iron oxide particles in a moving-bed reactor, which has proven to be more efficient than conventional processes. However, a thermodynamic barrier in the system limits the syngas yield. To overcome this barrier, a novel chemical looping cross-current system has been developed and investigated, achieving significantly higher syngas yield compared to the cocurrent system under isothermal conditions.
Article
Energy & Fuels
Zhuo Cheng, Deven S. Baser, Vedant Shah, Jonathan A. Fan, Liang-Shih Fan
Review
Chemistry, Multidisciplinary
Lang Qin, Zhuo Cheng, Deven Baser, Tyler Goldenbaum, Jonathan A. Fan, Liang-Shih Fan
REACTION CHEMISTRY & ENGINEERING
(2020)