Enhanced Methane Conversion using Ni-doped Calcium Ferrite Oxygen Carriers in Chemical Looping Partial Oxidation Systems with CO2 Utilization

Author(s):  
Vedant Shah ◽  
Zhuo Cheng ◽  
Pinak Mohapatra ◽  
Liang-Shih Fan

Chemical looping partial oxidation (CLPO) is a novel technology for converting methane into high quality syngas that can be further converted into liquid fuels. In the present work, Ni-doped Ca2Fe2O5...

2021 ◽  
Vol 282 ◽  
pp. 116111
Author(s):  
Vedant Shah ◽  
Zhuo Cheng ◽  
Deven S. Baser ◽  
Jonathan A. Fan ◽  
Liang-Shih Fan

2012 ◽  
Vol 550-553 ◽  
pp. 974-978
Author(s):  
Wen Yan Li ◽  
Xing Lei Liu ◽  
Qiu Luan Chen ◽  
Feng Ming Chu

Chemical-looping combustion (CLC) is a novel technology, which has inherent property of separating the greenhouse gas CO2, which uses oxygen carriers to transfer oxygen for combustion from air to fuel. The reactivity of Fe2O3/Al2O3 oxygen carrier was assessed by measuring their ability to oxidize CO. The kinetics and mechanism of oxygen carrier have been studied by TG and DTG techniques. The kinetic mechanism function of the reaction between Fe2O3/Al2O3 and CO has been built using the Coats-Redfern equation.


2016 ◽  
Vol 830 ◽  
pp. 30-37 ◽  
Author(s):  
Renato Dias Barbosa ◽  
Gilberto Marques da Cruz ◽  
Pedro Henrique Lopes Nunes Abreu dos Santos ◽  
Gilberto Garcia Cortez ◽  
José Augusto Jorge Rodrigues

Chemical-Looping Combustion (CLC) and Chemical-Looping Reforming (CLR) processes are technologies in development, considered as economically viable alternatives for CO2 mitigation. Both processes employ two interconnected reactors (air reactor and fuel reactor), by which oxides particles (called oxygen carriers) circulate. CLC process produces heat with inherent separation of CO2 from gaseous hydrocarbons combustion. CLR process performs the fuel partial oxidation, generating synthesis gas (H2 and CO), which is the major industrial intermediate for hydrogen (H2) and other hydrocarbons production, thru Fischer-Tropsch reactions. The employment of OCs enables the total or partial oxidation of fuel, in the absence of atmospheric air, which allows great reduction of the separation costs. Nickel-based OCs are the most investigated, showing high performance and reactivity. This work presents the synthesis of OCs composed by different contents of nickel oxides supported on alumina, textural, physical and chemical characterizations by several techniques, and experimental results obtained when these materials were applied to CLC and CLR processes, using CH4 as fuel, mixed or not, with H2O or CO2. The results showed the potential industrial applications of these materials, which are preferentially selective to the CLR process, and the addiction of H2O or CO2 greatly reduces the carbon deposition.


2016 ◽  
Vol 18 (24) ◽  
pp. 16423-16435 ◽  
Author(s):  
Zhuo Cheng ◽  
Lang Qin ◽  
Mengqing Guo ◽  
Jonathan A. Fan ◽  
Dikai Xu ◽  
...  

We investigated the interaction between methane and iron oxide oxygen carrier for chemical looping reaction systems and found the oxygen vacancies can facilitate methane conversion.


2016 ◽  
Vol 18 (47) ◽  
pp. 32418-32428 ◽  
Author(s):  
Zhuo Cheng ◽  
Lang Qin ◽  
Mengqing Guo ◽  
Mingyuan Xu ◽  
Jonathan A. Fan ◽  
...  

We found that oxygen vacancies can promote CH4 partial oxidation on iron oxide oxygen carriers during the chemical looping process.


2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Yan Liu ◽  
Lang Qin ◽  
Zhuo Cheng ◽  
Josh W. Goetze ◽  
Fanhe Kong ◽  
...  

AbstractChemical looping methane partial oxidation provides an energy and cost effective route for methane utilization. However, there is considerable CO2 co-production in current chemical looping systems, rendering a decreased productivity in value-added fuels or chemicals. In this work, we demonstrate that the co-production of CO2 can be dramatically suppressed in methane partial oxidation reactions using iron oxide nanoparticles embedded in mesoporous silica matrix. We experimentally obtain near 100% CO selectivity in a cyclic redox system at 750–935 °C, which is a significantly lower temperature range than in conventional oxygen carrier systems. Density functional theory calculations elucidate the origins for such selectivity and show that low-coordinated lattice oxygen atoms on the surface of nanoparticles significantly promote Fe–O bond cleavage and CO formation. We envision that embedded nanostructured oxygen carriers have the potential to serve as a general materials platform for redox reactions with nanomaterials at high temperatures.


Author(s):  
Thelma De los Rios ◽  
Daniel Lardizabal Gutierrez ◽  
Virginia Collins Martínez ◽  
Alejandro López Ortiz

Novel proposed processes for H2 production and energy generation such as partial oxidation of hydrocarbons (POX-MeO) and chemical looping process (CLP), respectively require the use of solid oxides as oxygen carriers. In POX-MeO the required oxygen for the partial oxidation of methane is provided by a transition metal oxide (MeO). First, H2 is produced through CH4+MeO = CO+H2+Me. Secondly, Me is re-oxidized through Me+O2 = MeO to regenerate the oxygen carrier. In the CL process, CH4 is being completely oxidized through CH2 + MeO = CO2 + H2O + Me producing heat and CO2 ready for sequestration. Finally, Me is re-oxidized using air to regenerate the Me back to MeO. In both processes the regenerated MeO is sent back to the initial step to result in a cyclic operation. Continuous exposure of MeO to Redox cycles frequently produces sinterization and MeO stabilization is needed to avoid loss of activity. The objective of this study is to investigate the stabilization effect of TiO2 in Co3O4 during Redox cycles to be used as an oxygen carrier using CoxTiOy type spinnels. Characterization of the synthesized samples included XRD, TPR, and SEM. Co2TiO4 and CoTiO3 spinnels were synthesized by solid state reaction. TGA and TPR Redox performance cycles of Co3O4 produced sintering, while results using a Co2TiO4 spinnel structure suggest a strong stabilization effect of TiO2 on Co. Ten Redox cycles using H2 and CH4 as reducing agents and a mixture of O2/N2 as oxidizer resulted in fixation of Co to TiO2 avoiding sintering.


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