The Experts below are selected from a list of 10491 Experts worldwide ranked by ideXlab platform
Liangshih Fan - One of the best experts on this subject based on the ideXlab platform.
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metal oxide redox chemistry for Chemical Looping processes
Nature Reviews Chemistry, 2018Co-Authors: Liang Zeng, Liangshih Fan, Zhuo Cheng, Jonathan A. Fan, Jinlong GongAbstract:Chemical Looping offers a versatile platform to convert fuels and oxidizers in a clean and efficient manner. Central to this technology are metal oxide materials that can oxidize fuels, affording a reduced material that can be reoxidized to close the loop. Recent years have seen substantial advances in the design, formulation and manufacture of these oxygen carrier materials and their incorporation into Chemical Looping reactors for the production of various Chemicals. This Review describes the mechanisms by which oxygen carriers undergo redox reactions and how these carriers can be incorporated into robust Chemical Looping reactors. One promising technology for modern energy and Chemical conversions is Chemical Looping, central to which are redox cycles of metal oxides. This Review describes Chemical Looping schemes and the mechanisms by which metal oxide particles enable these technologies.
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New Insight into the Development of Oxygen Carrier Materials for Chemical Looping Systems
Engineering, 2018Co-Authors: Zhuo Cheng, Lang Qin, Jonathan A. Fan, Liangshih FanAbstract:Abstract Chemical Looping combustion (CLC) and Chemical Looping reforming (CLR) are innovative technologies for clean and efficient hydrocarbon conversion into power, fuels, and Chemicals through cyclic redox reactions. Metal oxide materials play an essential role in the Chemical Looping redox processes. During reduction, the oxygen carriers donate the required amount of oxygen ions for hydrocarbon conversion and product synthesis. In the oxidation step, the depleted metal oxide oxygen carriers are replenished with molecular oxygen from the air while heat is released. In recent years, there have been significant advances in oxygen carrier materials for various Chemical Looping applications. Among these metal oxide materials, iron-based oxygen carriers are attractive due to their high oxygen-carrying capacity, cost benefits, and versatility in applications for Chemical Looping reactions. Their reactivity can also be enhanced via structural design and modification. This review discusses recent advances in the development of oxygen carrier materials and the mechanisms of hydrocarbon conversion over these materials. These advances will facilitate the development of oxygen carrier materials for more efficient Chemical Looping technology applications.
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Handbook of Clean Energy Systems - Chemical Looping Combustion and Gasification
Handbook of Clean Energy Systems, 2015Co-Authors: Liangshih Fan, Andrew Tong, Samuel Bayham, Mandar Kathe, Elena Y. Chung, Liang ZengAbstract:With the emerging challenge of climate change and the continued escalation of energy demands, innovative and flexible fuel conversion technologies are necessary and gaining recognition. Chemical Looping technologies have the potential to not only reduce energy costs, but also to mitigate carbon emissions. Historically, the general concept of this reduction–oxidation mechanism has been suggested, but the process was never commercialized. Recent interests in carbon capture techniques have revitalized the adaptive Chemical Looping system. Chemical Looping technologies can utilize both gaseous and solid fuels such as natural gas and coal, respectively, for power, hydrogen, or Chemical generation. However, the success of technological adoption requires a thorough understanding of the types of Chemical Looping techniques, the design considerations, and the reactor modes of configurations. Current large-scale testing units are examined with the hope for near-term advancement and future commercial application. Keywords: Chemical Looping; Chemical Looping combustion; carbon capture; oxygen carrier; synthesis gas
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Chemical Looping technology for energy and Chemical production
Wiley Interdisciplinary Reviews: Energy and Environment, 2015Co-Authors: Samuel Bayham, Andrew Tong, Mandar Kathe, Liangshih FanAbstract:Chemical Looping has been considered as a promising technology for CO2 capture and for producing electricity and/or Chemicals from various carbonaceous feedstocks. This article provides an overview of Chemical Looping processes, their potential process configurations, and applications for power and Chemical production. The designs and results of various demonstration units are discussed in relation to parameters required for commercialization. Furthermore, the barriers to commercialization of a Chemical Looping plant for power or syngas production are illustrated. WIREs Energy Environ 2016, 5:216–241. doi: 10.1002/wene.173 For further resources related to this article, please visit the WIREs website.
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Chemical Looping Technology: Oxygen Carrier Characteristics
Annual review of chemical and biomolecular engineering, 2015Co-Authors: Siwei Luo, Liang Zeng, Liangshih FanAbstract:Chemical Looping processes are characterized as promising carbonaceous fuel conversion technologies with the advantages of manageable CO2 capture and high energy conversion efficiency. Depending on the Chemical Looping reaction products generated, Chemical Looping technologies generally can be grouped into two types: Chemical Looping full oxidation (CLFO) and Chemical Looping partial oxidation (CLPO). In CLFO, carbonaceous fuels are fully oxidized to CO2 and H2O, as typically represented by Chemical Looping combustion with electricity as the primary product. In CLPO, however, carbonaceous fuels are partially oxidized, as typically represented by Chemical Looping gasification with syngas or hydrogen as the primary product. Both CLFO and CLPO share similar operational features; however, the optimum process configurations and the specific oxygen carriers used between them can vary significantly. Progress in both CLFO and CLPO is reviewed and analyzed with specific focus on oxygen carrier developments that characterize these technologies.
Anders Lyngfelt - One of the best experts on this subject based on the ideXlab platform.
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Chemical Looping Combustion: Status and Development Challenges
Energy & Fuels, 2020Co-Authors: Anders LyngfeltAbstract:Because the CO2 capture is inherent in Chemical Looping combustion (CLC), thus ideally avoiding costly gas separation, this process has potential for uniquely low costs of CO2 capture. The review r...
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(Fe1-xMnx)TiyO3 based Oxygen Carriers for Chemical-Looping Combustion and Chemical-Looping with Oxygen Uncoupling
Energy Procedia, 2014Co-Authors: Magnus Rydén, Tobias Mattisson, Malin Källén, Dazheng Jing, Ali Hedayati, Anders LyngfeltAbstract:The manganese based ilmenite analogue pyrophanite (MnTiO3) and six other combined (Fe1-xMnx)TiyO3 oxides have been examined as oxygen-carrier materials for Chemical-Looping combustion (CLC) and Chemical-Looping with oxygen uncoupling (CLOU). Particles with different compositions were manufactured by spray drying and studied by consecutive reduction and oxidation at 850-1050°C in a batch fluidized-bed reactor using CH4 as fuel. A fuel conversion of 80-99% could be achieved with most materials, with different formulations being favored at different temperature levels. The exception was pure MnTiO3 which had very limited reactivity with CH4. The oxygen uncoupling behavior was examined by exposing the oxygen-carrier particles to an inert atmosphere of N2. The apparent equilibrium concentration during fluidization with pure N 2 ranged from zero to 0.9% O2, depending on temperature and particle composition. One material (Fe0.50Mn0.50) TiO3 was selected and further examined by 12 h of experiments in a small continuously operating circulating fluidized-bed reactor. Up to 80% conversion of natural gas was achieved at 910°C , but defluidization occurred when the temperature was increased to 950°C .
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Materials for Chemical-Looping combustion
2011Co-Authors: Anders Lyngfelt, Tobias MattissonAbstract:Chemical-Looping combustion (CLC) is a combustion technology with inherent separation of the greenhouse gas CO2. Two inter-connected fluidized beds, a fuel reactor and an air reactor, are used. The fuel is oxidized by the metal oxide in the fuel reactor, and the metal oxide is regenerated in the air reactor. The outlet gas from the fuel reactor consists of CO2 and H2O, easily separated by condensation. Oxides of Ni, Co, Fe, Cu and Mn are used as oxygen-carrier materials. More than 900 materials have been investigated and some have been used in actual operation in Chemical-Looping combustors in the size range 0.3 – 140 kW. The total time of operational experience is more than 4000 hours. The work indicates that almost complete conversion of the fuel can be obtained and 100% CO2 capture is possible. Most work so far has been focused on gaseous fuels, but the direct application to solid fuels is also rapidly advancing. Moreover, Chemical-Looping technologies to produce hydrogen with inherent CO2 capture are being developed. This paper presents an overview of the current status of the technology with focus on materials.
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nio supported on mg zro2 as oxygen carrier for Chemical Looping combustion and Chemical Looping reforming
Energy and Environmental Science, 2009Co-Authors: Magnus Rydén, M. Johansson, Anders Lyngfelt, Tobias MattissonAbstract:Oxygen-carrier particles consisting of 40 wt% NiO supported on 60 wt% Mg-stabilized ZrO2 were produced by freeze granulation and examined as oxygen carrier for Chemical-Looping applications. Firstly, the particles were examined by oxidation and reduction experiments in a batch fluidized-bed reactor. These experiments indicated very high reactivity with CH4 and low affinity for carbon formation. For highly oxidized particles the products were CO2 and H2O, while for reduced particles they were CO and H2. Secondly, the particles were examined by 40 hours of operation in a small circulating fluidized-bed reactor, using natural gas as fuel. For Chemical-Looping combustion, there was complete conversion of fuel into products with high selectivity towards CO2 and H2O. At 950 °C, a combustion efficiency of 99.3% was achieved, which is only 0.1% point below the theoretical maximum, i.e. thermodynamic equilibrium. For Chemical-Looping reforming, the conversion of fuel was 99.9% or higher, with high selectivity towards CO and H2. Operating at the desired process parameters, which was a fuel reactor temperature of 950 °C and an air ratio of 0.30, worked flawlessly. When only natural gas was used as fuel there was slight formation of solid carbon in the fuel reactor. Adding 30 vol% steam to the fuel removed the carbon formation. The particles retained their physical and Chemical structure reasonably well during operation. Approximately 5% of the particles added to the reactor were lost as fines during the first hours of operation. Further, the porosity of the particles increased somewhat during operation. The density was 10% lower for used particles, compared to fresh.
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Chemical-Looping Combustion Status of Development
Fuel, 2008Co-Authors: Anders Lyngfelt, M. Johansson, Tobias MattissonAbstract:Chemical-Looping combustion (CLC) is a combustion technology with inherent separation of the greenhouse gas CO2. The technique involves the use of a metal oxide as an oxygen carrier which transfers oxygen from combustion air to the fuel, and hence a direct contact between air and fuel is avoided. Two inter-connected fluidized beds, a fuel reactor and an air reactor, are used in the process. In the fuel reactor, the metal oxide is reduced by the reaction with the fuel and in the air reactor; the reduced metal oxide is oxidized with air. The outlet gas from the fuel reactor consists of CO2 and H2O, and almost pure stream of CO2 is obtained when water is condensed. Considerable research has been conducted on CLC in the last years with respect to oxygen carrier development, reactor design, system efficiencies and prototype testing. In 2002 the process was a paper concept, albeit with some important but limited laboratory work on oxygen carrier particles. Today more than 600 materials have been tested and the technique has been successfully demonstrated in Chemical-Looping combustors in the size range 0.3 50 kW, using different types of oxygen carriers based on the metals Ni, Co, Fe, Cu and Mn. The total time of operational experience is more than a thousand hours. From these tests it can be established that almost complete conversion of the fuel can be obtained and 100% CO2 capture is possible. Most work so far has been focused on gaseous fuels, but the direct application to solid fuels is also being studied. Moreover, the same principle of oxygen transfer is used in Chemical-Looping reforming (CLR), which involves technologies to produce hydrogen with inherent CO2 capture. This paper presents an overview of the research performed on CLC and CLR highlights the current status of the technology.
Tobias Mattisson - One of the best experts on this subject based on the ideXlab platform.
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(Fe1-xMnx)TiyO3 based Oxygen Carriers for Chemical-Looping Combustion and Chemical-Looping with Oxygen Uncoupling
Energy Procedia, 2014Co-Authors: Magnus Rydén, Tobias Mattisson, Malin Källén, Dazheng Jing, Ali Hedayati, Anders LyngfeltAbstract:The manganese based ilmenite analogue pyrophanite (MnTiO3) and six other combined (Fe1-xMnx)TiyO3 oxides have been examined as oxygen-carrier materials for Chemical-Looping combustion (CLC) and Chemical-Looping with oxygen uncoupling (CLOU). Particles with different compositions were manufactured by spray drying and studied by consecutive reduction and oxidation at 850-1050°C in a batch fluidized-bed reactor using CH4 as fuel. A fuel conversion of 80-99% could be achieved with most materials, with different formulations being favored at different temperature levels. The exception was pure MnTiO3 which had very limited reactivity with CH4. The oxygen uncoupling behavior was examined by exposing the oxygen-carrier particles to an inert atmosphere of N2. The apparent equilibrium concentration during fluidization with pure N 2 ranged from zero to 0.9% O2, depending on temperature and particle composition. One material (Fe0.50Mn0.50) TiO3 was selected and further examined by 12 h of experiments in a small continuously operating circulating fluidized-bed reactor. Up to 80% conversion of natural gas was achieved at 910°C , but defluidization occurred when the temperature was increased to 950°C .
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Materials for Chemical-Looping combustion
2011Co-Authors: Anders Lyngfelt, Tobias MattissonAbstract:Chemical-Looping combustion (CLC) is a combustion technology with inherent separation of the greenhouse gas CO2. Two inter-connected fluidized beds, a fuel reactor and an air reactor, are used. The fuel is oxidized by the metal oxide in the fuel reactor, and the metal oxide is regenerated in the air reactor. The outlet gas from the fuel reactor consists of CO2 and H2O, easily separated by condensation. Oxides of Ni, Co, Fe, Cu and Mn are used as oxygen-carrier materials. More than 900 materials have been investigated and some have been used in actual operation in Chemical-Looping combustors in the size range 0.3 – 140 kW. The total time of operational experience is more than 4000 hours. The work indicates that almost complete conversion of the fuel can be obtained and 100% CO2 capture is possible. Most work so far has been focused on gaseous fuels, but the direct application to solid fuels is also rapidly advancing. Moreover, Chemical-Looping technologies to produce hydrogen with inherent CO2 capture are being developed. This paper presents an overview of the current status of the technology with focus on materials.
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nio supported on mg zro2 as oxygen carrier for Chemical Looping combustion and Chemical Looping reforming
Energy and Environmental Science, 2009Co-Authors: Magnus Rydén, M. Johansson, Anders Lyngfelt, Tobias MattissonAbstract:Oxygen-carrier particles consisting of 40 wt% NiO supported on 60 wt% Mg-stabilized ZrO2 were produced by freeze granulation and examined as oxygen carrier for Chemical-Looping applications. Firstly, the particles were examined by oxidation and reduction experiments in a batch fluidized-bed reactor. These experiments indicated very high reactivity with CH4 and low affinity for carbon formation. For highly oxidized particles the products were CO2 and H2O, while for reduced particles they were CO and H2. Secondly, the particles were examined by 40 hours of operation in a small circulating fluidized-bed reactor, using natural gas as fuel. For Chemical-Looping combustion, there was complete conversion of fuel into products with high selectivity towards CO2 and H2O. At 950 °C, a combustion efficiency of 99.3% was achieved, which is only 0.1% point below the theoretical maximum, i.e. thermodynamic equilibrium. For Chemical-Looping reforming, the conversion of fuel was 99.9% or higher, with high selectivity towards CO and H2. Operating at the desired process parameters, which was a fuel reactor temperature of 950 °C and an air ratio of 0.30, worked flawlessly. When only natural gas was used as fuel there was slight formation of solid carbon in the fuel reactor. Adding 30 vol% steam to the fuel removed the carbon formation. The particles retained their physical and Chemical structure reasonably well during operation. Approximately 5% of the particles added to the reactor were lost as fines during the first hours of operation. Further, the porosity of the particles increased somewhat during operation. The density was 10% lower for used particles, compared to fresh.
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Chemical-Looping Combustion Status of Development
Fuel, 2008Co-Authors: Anders Lyngfelt, M. Johansson, Tobias MattissonAbstract:Chemical-Looping combustion (CLC) is a combustion technology with inherent separation of the greenhouse gas CO2. The technique involves the use of a metal oxide as an oxygen carrier which transfers oxygen from combustion air to the fuel, and hence a direct contact between air and fuel is avoided. Two inter-connected fluidized beds, a fuel reactor and an air reactor, are used in the process. In the fuel reactor, the metal oxide is reduced by the reaction with the fuel and in the air reactor; the reduced metal oxide is oxidized with air. The outlet gas from the fuel reactor consists of CO2 and H2O, and almost pure stream of CO2 is obtained when water is condensed. Considerable research has been conducted on CLC in the last years with respect to oxygen carrier development, reactor design, system efficiencies and prototype testing. In 2002 the process was a paper concept, albeit with some important but limited laboratory work on oxygen carrier particles. Today more than 600 materials have been tested and the technique has been successfully demonstrated in Chemical-Looping combustors in the size range 0.3 50 kW, using different types of oxygen carriers based on the metals Ni, Co, Fe, Cu and Mn. The total time of operational experience is more than a thousand hours. From these tests it can be established that almost complete conversion of the fuel can be obtained and 100% CO2 capture is possible. Most work so far has been focused on gaseous fuels, but the direct application to solid fuels is also being studied. Moreover, the same principle of oxygen transfer is used in Chemical-Looping reforming (CLR), which involves technologies to produce hydrogen with inherent CO2 capture. This paper presents an overview of the research performed on CLC and CLR highlights the current status of the technology.
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novel oxygen carrier materials for Chemical Looping combustion and Chemical Looping reforming laxsr1 xfeyco1 yo3 δ perovskites and mixed metal oxides of nio fe2o3 and mn3o4
International Journal of Greenhouse Gas Control, 2008Co-Authors: Magnus Rydén, Anders Lyngfelt, Tobias Mattisson, De Chen, Anders Holmen, Erlend BjorgumAbstract:Solid oxygen-carrier materials for Chemical-Looping applications have been examined by reduction with CH4 and oxidation with air in a fixed-bed quartz reactor at 900oC. Four perovskite materials, three metal-oxide materials and four metal-oxide mixtures have been studied. It was found that LaxSr1─xFeO3─δ perovskites provided very high selectivity towards CO/H2 and should be well suited for Chemical-Looping reforming. Substituting La for Sr was found to increase the oxygen capacity of these materials, but reduced the selectivity towards CO/H2 and the reactivity with CH4. La0.5Sr0.5Fe0.5Co0.5O3─δ was found to be feasible for Chemical-Looping combustion applications. NiO/MgAl2O4 propagated formation of solid carbon, likely due to the catalytic properties of metallic Ni. Fe2O3/MgAl2O4 had properties that made it interesting both for Chemical-Looping combustion and Chemical-Looping reforming. Adding 1% NiO particles to a bed of Fe2O3-particles increased both reactivity with CH4 and selectivity towards CO/H2 for reforming applications. Mn3O4/MgZrO2 was found to be suitable for Chemical-Looping combustion applications, but it could not be verified that adding NiO produced any positive effects.
Juan Adánez - One of the best experts on this subject based on the ideXlab platform.
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Negative CO2 emissions through the use of biofuels in Chemical Looping technology: A review
Applied Energy, 2018Co-Authors: T. Mendiara, Francisco García-labiano, Pilar Gayán, A. Abad, L.f. De Diego, M. Izquierdo, Juan AdánezAbstract:In order to limit the increase in the global average temperature to 2 °C or below, the Paris Agreement proposed the reduction of CO2 emissions throughout this century. Bioenergy with CO2 capture and storage (BECCS) technologies represent an interesting option in order to allow this goal to be metgoal, because they are able to achieve negative CO2 emissions. Chemical Looping (CL) is recognized as one of the most innovative CO2 capture technologies owing to its low energy penalty. CL processes permit the utilization of renewable fuels in a nitrogen-free atmosphere, given that the required oxygen is supplied by solid oxygen carriers. The present work presents an overview of the status of development of the use of biofuels in Chemical Looping technologies, including Chemical Looping combustion (CLC) and Chemical Looping with oxygen uncoupling (CLOU) for the production of heat/electricity, as well as Chemical Looping reforming (CLR), Chemical Looping gasification (CLG) and Chemical Looping coupled with water splitting (CLWS) for syngas/H2 generation. The main milestones in the development of such processes are shown, and the future trends and opportunities for CL technology with biofuels are discussed.
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Combustion and Reforming of Liquid Fossil Fuels through Chemical Looping Processes: Integration of Chemical Looping Processes in a Refinery
Energy Procedia, 2017Co-Authors: Francisco García-labiano, E. García-díez, Luis Francisco De Diego, Alberto Abad, Pilar Gayán, A Serrano, Juan AdánezAbstract:Oil refining processes demand and use vast quantities of energy and thus are responsible for the emission of a great deal of CO2. In addition, hydrogen is used in oil refineries for hydrodesulfurization and hydrocraking processes. In this sense, the integration of Chemical Looping technology in an oil refinery using vacuum residues as fuel could drive to significant reductions in CO2 emissions. In this work, Chemical Looping Combustion (CLC) and Chemical Looping Reforming (CLR) experiments have been carried out in a continuously operated 1 kWth unit using a Cu- and Ni-based oxygen carrier, respectively. Diesel, synthetic and mineral lubricant oil were used as fuels as a previous step to the use of low grade residues. Regarding Chemical Looping Combustion conditions, almost 100% of combustion efficiency and full carbon capture were obtained at low oxygen carrier-to-fuel molar ratios (ø≥1.6). Regarding Chemical Looping Reforming conditions, a syngas containing a H2 concentration over 50 vol.% in dry basis was obtained with the additional advantage of reaching 100% CO2 capture efficiency in the process. In all cases, syngas composition obtained was close to the given by the thermodynamic equilibrium. These results provide a basis for concluding that the integration of Chemical Looping processes for heat/steam and hydrogen production in an oil refinery is feasible and could lead to significant environmental advantages.
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Process Comparison for Biomass Combustion: In Situ Gasification‐Chemical Looping Combustion (iG‐CLC) versus Chemical Looping with Oxygen Uncoupling (CLOU)
Energy Technology, 2016Co-Authors: T. Mendiara, Francisco García-labiano, Alberto Abad, Pilar Gayán, L.f. De Diego, Iñaki Adánez-rubio, Juan AdánezAbstract:Biomass is an interesting renewable fuel to be used in Chemical Looping combustion (CLC). If the CO2 generated during biomass combustion is captured, the negative-CO2 emission concept is possible. This work evaluates the differences between biomass combustion under two CLC configurations developed for solid fuels: in situ gasification-Chemical Looping combustion (iG-CLC) and Chemical Looping with oxygen uncoupling (CLOU). The combustion efficiency, tar emission, and carbon capture efficiency obtained at different fuel reactor temperatures in a continuous 1.5 kWth CLC unit were compared. Higher carbon capture efficiencies were reached under the CLOU mode, with no tar emission. Although in the iG-CLC mode tars were always present in the fuel reactor outlet gas, high carbon capture was reached by using CO2 as gasifying agent. Moreover, a simulation of the effect of the solid inventory necessary in the fuel reactor to reach certain carbon capture efficiency was performed for both processes. Lower solid inventories are needed in the CLOU configuration, but the cost for the oxygen carrier used in CLOU is higher than in iG-CLC.
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Chemical Looping combustion of gaseous fuels
Calcium and Chemical Looping Technology for Power Generation and Carbon Dioxide (CO2) Capture, 2015Co-Authors: Juan AdánezAbstract:This chapter discusses the work done on Chemical Looping combustion applied to gaseous fuels, giving an overview of the experimental results obtained with different oxygen carriers in continuous units of different size. Effects of fuel gas composition and presence of sulphur impurities on combustion performance with carriers of different metal oxides are presented and discussed. Modelling of fuel and air reactors is helpful for the design, optimization and scale-up of Chemical Looping combustion process. Kinetics of redox reactions for some oxygen carriers are analysed and put together with gas and solid flow patterns inside circulating fluidized bed reactors for modelling and design.
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Combustion and Reforming of Ethanol in a Chemical Looping Continuous Unit
Energy Procedia, 2014Co-Authors: Francisco García-labiano, E. García-díez, Luis Francisco De Diego, Alberto Abad, Pilar Gayán, A Serrano, Juan AdánezAbstract:Combustion and reforming tests based on Chemical Looping processes have been carried out in a continuously operated 1 kWth unit using a Ni-based oxygen carrier and ethanol as fuel. Regarding Chemical Looping Combustion conditions, almost 100% of combustion efficiency was obtained at low oxygen-to-carrier molar ratios (ϕ⩾2.2). Regarding Chemical Looping Reforming conditions, a H2 concentration over 60 vol.% in dry basis was obtained, which was similar to the composition given by the thermodynamic equilibrium. The reactivity of the oxygen-carrier was maintained high and constant during all the operation tests. The tests demonstrated that negative CO2 emissions can be reached, from both the combustion and the H2 production processes, based on Chemical Looping technologies if the ethanol used is obtained from renewable sources.
Magnus Rydén - One of the best experts on this subject based on the ideXlab platform.
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Chemical Looping combustion of liquid fuels
Calcium and Chemical Looping Technology for Power Generation and Carbon Dioxide (CO2) Capture, 2015Co-Authors: Magnus RydénAbstract:Up to this point comparably little research has been conducted concerning Chemical Looping combustion of liquid fuels. This article provides an overview of the field and discussion of the subject. It is shown that basic oxygen carrier materials such as NiO, CuO, Mn3O4 and FeTiO3 perform in similar way when liquid fuels are used as when gaseous fuels are used, and that the choice of fuel feeding system is very important and will be different for different kinds of liquid fuels. Light liquid fuels can be vaporized before being fed to a reactor systems similar in design to those used for gaseous fuels. Heavy liquid fuels have sufficiently high boiling point for coking to occur before complete vaporization which makes fuel feeding more complicated. It is concluded that Chemical Looping combustion of liquid fuels is feasible and that the most likely application is the generation of heat and power with CO2 capture using heavy oils or bitumen as fuel. Niche applications involving other kinds of liquid fuels are also briefly discussed.
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(Fe1-xMnx)TiyO3 based Oxygen Carriers for Chemical-Looping Combustion and Chemical-Looping with Oxygen Uncoupling
Energy Procedia, 2014Co-Authors: Magnus Rydén, Tobias Mattisson, Malin Källén, Dazheng Jing, Ali Hedayati, Anders LyngfeltAbstract:The manganese based ilmenite analogue pyrophanite (MnTiO3) and six other combined (Fe1-xMnx)TiyO3 oxides have been examined as oxygen-carrier materials for Chemical-Looping combustion (CLC) and Chemical-Looping with oxygen uncoupling (CLOU). Particles with different compositions were manufactured by spray drying and studied by consecutive reduction and oxidation at 850-1050°C in a batch fluidized-bed reactor using CH4 as fuel. A fuel conversion of 80-99% could be achieved with most materials, with different formulations being favored at different temperature levels. The exception was pure MnTiO3 which had very limited reactivity with CH4. The oxygen uncoupling behavior was examined by exposing the oxygen-carrier particles to an inert atmosphere of N2. The apparent equilibrium concentration during fluidization with pure N 2 ranged from zero to 0.9% O2, depending on temperature and particle composition. One material (Fe0.50Mn0.50) TiO3 was selected and further examined by 12 h of experiments in a small continuously operating circulating fluidized-bed reactor. Up to 80% conversion of natural gas was achieved at 910°C , but defluidization occurred when the temperature was increased to 950°C .
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nio supported on mg zro2 as oxygen carrier for Chemical Looping combustion and Chemical Looping reforming
Energy and Environmental Science, 2009Co-Authors: Magnus Rydén, M. Johansson, Anders Lyngfelt, Tobias MattissonAbstract:Oxygen-carrier particles consisting of 40 wt% NiO supported on 60 wt% Mg-stabilized ZrO2 were produced by freeze granulation and examined as oxygen carrier for Chemical-Looping applications. Firstly, the particles were examined by oxidation and reduction experiments in a batch fluidized-bed reactor. These experiments indicated very high reactivity with CH4 and low affinity for carbon formation. For highly oxidized particles the products were CO2 and H2O, while for reduced particles they were CO and H2. Secondly, the particles were examined by 40 hours of operation in a small circulating fluidized-bed reactor, using natural gas as fuel. For Chemical-Looping combustion, there was complete conversion of fuel into products with high selectivity towards CO2 and H2O. At 950 °C, a combustion efficiency of 99.3% was achieved, which is only 0.1% point below the theoretical maximum, i.e. thermodynamic equilibrium. For Chemical-Looping reforming, the conversion of fuel was 99.9% or higher, with high selectivity towards CO and H2. Operating at the desired process parameters, which was a fuel reactor temperature of 950 °C and an air ratio of 0.30, worked flawlessly. When only natural gas was used as fuel there was slight formation of solid carbon in the fuel reactor. Adding 30 vol% steam to the fuel removed the carbon formation. The particles retained their physical and Chemical structure reasonably well during operation. Approximately 5% of the particles added to the reactor were lost as fines during the first hours of operation. Further, the porosity of the particles increased somewhat during operation. The density was 10% lower for used particles, compared to fresh.
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novel oxygen carrier materials for Chemical Looping combustion and Chemical Looping reforming laxsr1 xfeyco1 yo3 δ perovskites and mixed metal oxides of nio fe2o3 and mn3o4
International Journal of Greenhouse Gas Control, 2008Co-Authors: Magnus Rydén, Anders Lyngfelt, Tobias Mattisson, De Chen, Anders Holmen, Erlend BjorgumAbstract:Solid oxygen-carrier materials for Chemical-Looping applications have been examined by reduction with CH4 and oxidation with air in a fixed-bed quartz reactor at 900oC. Four perovskite materials, three metal-oxide materials and four metal-oxide mixtures have been studied. It was found that LaxSr1─xFeO3─δ perovskites provided very high selectivity towards CO/H2 and should be well suited for Chemical-Looping reforming. Substituting La for Sr was found to increase the oxygen capacity of these materials, but reduced the selectivity towards CO/H2 and the reactivity with CH4. La0.5Sr0.5Fe0.5Co0.5O3─δ was found to be feasible for Chemical-Looping combustion applications. NiO/MgAl2O4 propagated formation of solid carbon, likely due to the catalytic properties of metallic Ni. Fe2O3/MgAl2O4 had properties that made it interesting both for Chemical-Looping combustion and Chemical-Looping reforming. Adding 1% NiO particles to a bed of Fe2O3-particles increased both reactivity with CH4 and selectivity towards CO/H2 for reforming applications. Mn3O4/MgZrO2 was found to be suitable for Chemical-Looping combustion applications, but it could not be verified that adding NiO produced any positive effects.
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Novel oxygen-carrier materials for Chemical-Looping combustion and Chemical-Looping reforming; LaxSr1−xFeyCo1−yO3−δ perovskites and mixed-metal oxides of NiO, Fe2O3 and Mn3O4
International Journal of Greenhouse Gas Control, 2008Co-Authors: Magnus Rydén, Anders Lyngfelt, Tobias Mattisson, De Chen, Anders Holmen, Erlend BjorgumAbstract:Solid oxygen-carrier materials for Chemical-Looping applications have been examined by reduction with CH4 and oxidation with air in a fixed-bed quartz reactor at 900oC. Four perovskite materials, three metal-oxide materials and four metal-oxide mixtures have been studied. It was found that LaxSr1─xFeO3─δ perovskites provided very high selectivity towards CO/H2 and should be well suited for Chemical-Looping reforming. Substituting La for Sr was found to increase the oxygen capacity of these materials, but reduced the selectivity towards CO/H2 and the reactivity with CH4. La0.5Sr0.5Fe0.5Co0.5O3─δ was found to be feasible for Chemical-Looping combustion applications. NiO/MgAl2O4 propagated formation of solid carbon, likely due to the catalytic properties of metallic Ni. Fe2O3/MgAl2O4 had properties that made it interesting both for Chemical-Looping combustion and Chemical-Looping reforming. Adding 1% NiO particles to a bed of Fe2O3-particles increased both reactivity with CH4 and selectivity towards CO/H2 for reforming applications. Mn3O4/MgZrO2 was found to be suitable for Chemical-Looping combustion applications, but it could not be verified that adding NiO produced any positive effects.