scholarly journals Development of CuO-based oxygen carriers supported on diatomite and kaolin for chemical looping combustion

2021 ◽  
Vol 10 (4) ◽  
pp. e15110412831
Author(s):  
Romário Cezar Pereira da Costa ◽  
Rebecca Araújo Barros do Nascimento ◽  
Dulce Maria de Araújo Melo ◽  
Dener Silva Albuquerque ◽  
Rodolfo Luiz Bezerra de Araújo Medeiros ◽  
...  
Keyword(s):  
Reaction Rate ◽  
Direct Reduction ◽  
Oxygen Carrier ◽  
Chemical Looping Combustion ◽  
Chemical Looping ◽  
Impregnation Method ◽  
Oxygen Carriers ◽  
Fuel Gas ◽  
Promising Alternative ◽  
X Ray

Chemical Looping Combustion (CLC) technology has emerged as a promising alternative capable of restricting the effects of global warming due to anthropogenic gas emissions, especially CO2, through its inherent capture. This study aims to synthesize and evaluate Cu-based oxygen carriers supported on natural materials such as diatomite and kaolin, through the incipient wet impregnation method for CLC process applications. Oxygen carriers were characterized by X-ray diffraction (XRD), temperature-programmed reduction (TPR), and scanning electron microscopy with surface energy dispersive x-ray spectroscopy (SEM-EDS). The mechanical strength of the two oxygen carrier particles was determined after the sintering procedure resulting in high crushing force. Reactivity of oxygen carriers was evaluated in a thermobalance with CH4 and H2 gases. Different reaction pathways were attempted when undergoing the redox cycles: total direct reduction of CuO to Cu0 for Cu-K and partial reduction of CuO to Cu2O and CuO to Cu-D. However, the highest reactivity and reaction rate was achieved in Cu-D due to the pore structure of diatomite, the chemical composition and the resulting interaction between CuO and the support. H2 gas reactivity tests showed a higher conversion rate and greater stability between cycles for both oxygen carriers. Thus, the reducible CuO content present in Cu-Diatomite during the reactivity test with H2 as the fuel gas was ideal for achieving high solids conversion, tendency for greater stability and a higher reaction rate.

Experimental Investigation of Chemical Looping Combustion of CO with Fe-Based Oxygen Carrier

2014 ◽  
Vol 986-987 ◽  
pp. 72-75
Author(s):  
Qu Li ◽  
Chang Feng Lin ◽  
Jun Jiao Zhang ◽  
Wei Liang Cheng ◽  
Wu Qin
Keyword(s):  
Experimental Investigation ◽  
Oxygen Carrier ◽  
Chemical Looping Combustion ◽  
Chemical Looping ◽  
Oxygen Carriers ◽  
Thermo Gravimetric ◽  
Cu Doping ◽  
X Ray

Reaction activities of Ni-doped and Cu-doped Fe2O3 oxygen carriers (OCs) with CO were investigated using thermo gravimetric (TG-DTG).The structures of the prepared OC were characterized by X-ray diffract meter (XRD).TG-DTG investigations indicated that rational Ni and Cu doping could efficiently enhance the reactivity of Fe-base oxygen carrier for oxidizing CO under different conditions. And Fe-based OC doped with 20 wt. % Ni can realize the highest reactivity.

Effects of ZnO Addition on Fe2O3/Al2O3 Oxygen Carriers on CH4 Reduction for Chemical Looping Combustion

2016 ◽  
Vol 872 ◽  
pp. 196-200
Author(s):  
Sujinda Thongsermsuk ◽  
Benjapon Chalermsinsuwan ◽  
Prapan Kuchonthara ◽  
Pornpote Piumsomboon
Keyword(s):  
Oxygen Carrier ◽  
Synergetic Effect ◽  
Fixed Bed ◽  
Reduction Process ◽  
Fixed Bed Reactor ◽  
Chemical Looping Combustion ◽  
Chemical Looping ◽  
Oxygen Carriers ◽  
Fuel Gas ◽  
Physical Mixing

Fe2O3/Al2O3/ZnO oxygen carriers with small content ZnO (5 wt% to 10 wt%) were prepared by physical mixing method and were evaluated its capability as an oxygen carrier in a chemical looping combustion. The combustion was conducted by using CH4 as a fuel gas. The reduction process of Fe2O3/Al2O3/ZnO oxygen carrier was carried out in a fixed bed reactor. The solid reduction products were characterized by X-ray diffraction (XRD) and Scanning Electron Microscope with EDS Attachment (SEM-EDS). The results show that the reactivity of Fe2O3/Al2O3/ZnO oxygen carriers is greater than that of Fe2O3/Al2O3 which is implied the synergetic effect between ZnO and Fe2O3. XRD results show that the iron oxide in the oxygen carriers is reduced to metallic iron. SEM-EDS also shows that the iron agglomeration is prevented. Consequently, the suitable content of ZnO in oxygen carriers is ranged from 5 wt% to 10 wt%.

scholarly journals Evaluating the reactivity of CuO-TiO2 oxygen carrier for energy production technology with CO2 capture

2021 ◽  
Vol 10 (12) ◽  
pp. e514101220596
Author(s):  
Dener da Silva Albuquerque ◽  
Dulce Maria de Araújo Melo ◽  
Rodolfo Luiz Bezerra de Araújo Medeiros ◽  
Romário Cezar Pereira da Costa ◽  
Fernando Velcic Maziviero ◽  
...  
Keyword(s):  
Titanium Oxide ◽  
Structural Characteristics ◽  
Oxygen Carrier ◽  
Co2 Production ◽  
Chemical Looping Combustion ◽  
Chemical Looping ◽  
Oxygen Carriers ◽  
X Ray Diffraction ◽  
X Ray ◽  
Solid Oxygen

Chemical looping combustion (CLC) processes have been shown to be promising and effective in reducing CO2 production from the combustion of various fuels associated with the growing global demand for energy, as it promotes indirect fuel combustion through solid oxygen carriers (SOC). Thus, this study aims to synthesize, characterize and evaluate mixed copper and titanium oxide as a solid oxygen carrier for use in combustion processes with chemical looping. The SOC was synthesized based on stoichiometric calculations by the polymeric precursor method and characterized by: X-ray fluorescence (XRF), X-ray diffraction (XRD), Scanning Electron Microscopy (SEM-FEG) with EDS, and Programmed Temperature Reduction (PTR). The oxygen carrying capacity (ROC) and the speed index of the reduction and oxidation cycles were evaluated by Thermogravimetric Reactivity (TGA). The main reactive phase identified was: The CuO phase for the mixed copper and titanium oxide were identified and confirmed by X-ray diffraction using the Rietveld refinement method. The reactivity of the CuO-TiO2 system was high, obtaining a CH4 conversion rate above 90% and a speed index of 40%/min. Due to the structural characteristics and the reactivity tests of this material, it is concluded that mixed copper and titanium oxide have the necessary requirements to be used in chemical looping combustion (CLC) processes.

scholarly journals Effect of Fuel Gas Composition in Chemical-Looping Combustion with Ni-Based Oxygen Carriers. 1. Fate of Sulfur

2009 ◽  
Vol 48 (5) ◽  
pp. 2499-2508 ◽  
Author(s):  
Francisco García-Labiano ◽  
Luis F. de Diego ◽  
Pilar Gayán ◽  
Juan Adánez ◽  
Alberto Abad ◽  
...  
Keyword(s):  
Chemical Looping Combustion ◽  
Chemical Looping ◽  
Gas Composition ◽  
Oxygen Carriers ◽  
Fuel Gas

scholarly journals Na-β-Al2O3 stabilized Fe2O3 oxygen carriers for chemical looping water splitting: correlating structure with redox stability

2021 ◽  
Author(s):  
Nur Sena Yüzbasi ◽  
Andac Armutlulu ◽  
Thomas Huthwelker ◽  
Paula Abdala ◽  
Christoph Müller
Keyword(s):  
Fossil Fuels ◽  
Oxygen Carrier ◽  
Chemical Looping ◽  
Oxygen Carriers ◽  
Cycle Number ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Edx Analyses ◽  
H2 Yield

Chemical looping is an emerging technology to produce high purity hydrogen from fossil fuels or biomass with the simultaneous capture of the CO2 produced at the distributed scale. This process requires the availability of stable Fe2O3-based oxygen carriers. Fe2O3-Al2O3 based oxygen carriers exhibit a decay in the H2 yield with cycle number due to the formation of FeAl2O4 that cannot be re-oxidized. In this study, the addition of sodium (via a sodium salt) in the synthesis of Fe2O3-Al2O3 oxygen carriers was assessed as a means to counteract the cyclic deactivation of the oxygen carrier. Detailed insight into the oxygen carrier’s structure was gained by combined X-ray powder diffraction (XRD), X-ray absorption spectroscopy (XAS) at the Al, Na and Fe K-edges and scanning transmission electron microscopy/energy-dispersive X-ray spectroscopy (STEM/EDX) analyses. The addition of sodium prevented the formation of FeAl2O4 and stabilized the oxygen carrier via the formation of a layered structure, Na-β-Al2O3 phase. The resulting material, Na-β-Al2O3 stabilized Fe2O3, showed a very high H2 yield of ca. 13.3 mmol/g during 15 cycles.

scholarly journals Preventing Agglomeration of CuO-Based Oxygen Carriers for Chemical Looping Applications

2021 ◽  
Author(s):  
Qasim Imtiaz ◽  
Andac Armutlulu ◽  
Felix Donat ◽  
Muhammad Awais Naeem ◽  
Christoph Müller
Keyword(s):  
Thin Films ◽  
Focused Ion Beam ◽  
Pechini Method ◽  
Ion Beam ◽  
Oxygen Carrier ◽  
Structural Instability ◽  
Chemical Looping ◽  
Oxygen Carriers ◽  
Promising Alternative ◽  
Main Challenge

Chemical looping combustion (CLC) is a promising alternative to the conventional combustion-based, fossil fuel conversion processes. In CLC, a solid oxygen carrier is used to transfer oxygen from air to a carbonaceous fuel. This indirect combustion route allows for effective CO<sub>2</sub> capture since a sequestrable stream of CO<sub>2 </sub>is inherently produced without any need for energy-intensive CO<sub>2</sub> separation. From a thermodynamic point of view, CuO is arguably one of the most promising oxygen carrier candidates for CLC. However, the main challenge associated with the use of CuO for CLC is its structural instability at the typical operating temperatures of chemical looping processes, leading to severe thermal sintering and agglomeration. To minimize irreversible microstructural changes during CLC operation, CuO is commonly stabilized by a high Tammann temperature ceramic, e.g., Al<sub>2</sub>O<sub>3</sub>, MgAl<sub>2</sub>O<sub>4</sub>, etc. However, it has been observed that a high Tammann temperature support does not always provide a high resistance to agglomeration. This work aims at identifying descriptors that can be used to characterize accurately the agglomeration tendency of CuO-based oxygen carriers. CuO-based oxygen carriers supported on different metal oxides were synthesized using a Pechini method. The cyclic redox stability and agglomeration tendency of the synthesized materials was evaluated using both a thermo-gravimetric analyser and a lab-scale fluidized bed reactor at 900 °C using 10 vol. % H<sub>2</sub> in N<sub>2</sub> as the fuel and air for re-oxidation. In order to study the diffusion of Cu(O) during redox reactions, well-defined model surfaces comprising thin films of Cu/CuO and two different supports, viz. ZrO<sub>2</sub> or MgO, were prepared via magnetron sputtering. Energy dispersive X-ray (EDX) spectroscopy on focused ion beam (FIB)-cut cross-sections of the thin films revealed that Cu atoms have a tendency to diffuse outward through most of the films of the support material under redox conditions. The support that inhibits the outward movement of Cu(O), i.e. avoiding the presence of low melting Cu on the oxygen carrier surface, is found to provide the highest agglomeration resistance. The support MgO was found to possesses such diffusion characteristics.

scholarly journals Chemical Looping Combustion of Methane: A Technology Development View

2013 ◽  
Vol 2013 ◽  
pp. 1-15 ◽  
Author(s):  
Rutuja Bhoje ◽  
Ganesh R. Kale ◽  
Nitin Labhsetwar ◽  
Sonali Borkhade
Keyword(s):  
Technology Development ◽  
Oxygen Carrier ◽  
Clean Energy ◽  
Unit Weight ◽  
Chemical Looping Combustion ◽  
Process Conditions ◽  
Net Energy ◽  
Chemical Looping ◽  
Oxygen Carriers ◽  
Byproduct Formation

Methane is a reliable and an abundantly available energy source occurring in nature as natural gas, biogas, landfill gas, and so forth. Clean energy generation using methane can be accomplished by using chemical looping combustion. This theoretical study for chemical looping combustion of methane was done to consider some key technology development points to help the process engineer choose the right oxygen carrier and process conditions. Combined maximum product (H2O + CO2) generation, weight of the oxygen carrier, net enthalpy of CLC process, byproduct formation, CO2emission from the air reactor, and net energy obtainable per unit weight (gram) of oxygen carrier in chemical looping combustion can be important parameters for CLC operation. Carbon formed in the fuel reactor was oxidised in the air reactor and that increased the net energy obtainable from the CLC process but resulted in CO2emission from the air reactor. Use of CaSO4as oxygen carrier generated maximum energy (−5.3657 kJ, 800°C) per gram of oxygen carrier used in the CLC process and was found to be the best oxygen carrier for methane CLC. Such a model study can be useful to identify the potential oxygen carriers for different fuel CLC systems.

scholarly journals Comparison of oxygen carriers for chemical-looping combustion

2006 ◽  
Vol 10 (3) ◽  
pp. 93-107 ◽  
Author(s):  
Marcus Johansson ◽  
Tobias Mattisson ◽  
Anders Lyngfelt
Keyword(s):  
Fossil Fuels ◽  
Oxygen Carrier ◽  
High Reactivity ◽  
Chemical Looping Combustion ◽  
Chemical Looping ◽  
Oxygen Carriers ◽  
Reducing Conditions ◽  
Different Temperatures ◽  
Combustion Technology ◽  
Separation Of Co2

Chemical-looping combustion is a combustion technology with inherent separation of the greenhouse gas CO2. This technique involves combustion of fossil fuels by means of an oxygen carrier which transfers oxygen from the air to the fuel. In this manner a decrease in efficiency is avoided for the energy demanding separation of CO2 from the rest of the flue gases. Results from fifty oxygen carriers based on iron-, manganese- and nickel oxides on different inert materials are compared. The particles were prepared using freeze granulation, sintered at different temperatures and sieved to a size 125-180 mm. To simulate the environment the particles would be exposed to in a chemical-looping combustor, reactivity tests under alternating oxidizing and reducing conditions were performed in a laboratory fluidized bed-reactor of quartz. Reduction was performed in 50% CH4/50% H2O while the oxidation was carried out in 5% O2 in nitrogen. In general nickel particles are the most reactive, followed by manganese. Iron particles are harder but have a lower reactivity. An increase in sintering temperatures normally leads to an increase in strength and decrease in reactivity. Several particles investigated display a combination of high reactivity and strength as well as good fluidization behavior, and are feasible for use as oxygen carriers in chemical-looping combustion.

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