A Multi-scale model for CO2 capture: A Nickel-based oxygen carrier in Chemical-looping Combustion

In this paper an alternative to the so-called “oxy-fuel” combustion for CO2 capture is evaluated. “Chemical looping combustion” (CLC), is closely related to oxy-fuel combustion as the chemically bound oxygen reacts in a stoichiometric ratio with the fuel. In the CLC process the overall combustion reaction takes place in two reaction steps in two separate reactors. In the reduction reactor, the fuel is oxidized by the oxygen carrier, i.e., the metal oxide MeO. The metal oxide is reduced to a metal oxide with a lower oxidation number, Me, in the reaction with the fuel. In this manner, pure oxygen is supplied to the reaction with the fuel without using a traditional air separation plant, like cryogenic distillation of air. The paper presents a thermodynamic cycle analysis, where CLC is applied in a humid air turbine concept. Main parameters are identified, and these are varied to examine the influence on cycle efficiency. Results on cycle efficiency are presented and compared to other CO2 capture options. Further, an evaluation of the oxygen carrier, metals/oxides, is presented. An exergy analysis is carried out in order to understand where losses occur, and to explain the difference between CLC and conventional combustion. The oxidation reactor air inlet temperature and the oxidation reactor exhaust temperature have a significant impact on the overall efficiency. This can be attributed to the controlling effect of these parameters on the required airflow rate. An optimum efficiency of 55.9% has been found for a given set of input parameters. Crucial issues of oxygen carrier durability, chemical performance, and mechanical properties have been idealized, and further research on the feasibility of CLC is needed. Whether or not the assumption 100% gas conversion holds, is a crucial issue and remains to be determined experimentally. Successful long-term operation of chemical looping systems of this particular type has not yet been demonstrated. The simulation points out a very promising potential of CLC as a power/heat generating method with inherent capture of CO2. Exergy analysis show reduced irreversibilities for CLC compared to conventional combustion. Simulations of this type will prove useful in designing CLC systems in the future when promizing oxygen carriers have been investigated in more detail .

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Chemical Looping Combustion-Analysis of Natural Gas Fired Power Cycles With Inherent CO2 Capture

Volume 7: Turbo Expo 2004 ◽

10.1115/gt2004-53359 ◽

2004 ◽

Cited By ~ 14

Author(s):

Rehan Naqvi ◽

Olav Bolland ◽

O̸yvind Brandvoll ◽

Kaare Helle

Keyword(s):

Metal Oxide ◽

Co2 Capture ◽

Oxygen Carrier ◽

Fuel Combustion ◽

Combined Cycle ◽

Reactor System ◽

Chemical Looping Combustion ◽

Chemical Looping ◽

Turbine Cooling ◽

Steam Cycle

In this paper an alternative to so-called ‘oxy-fuel’ combustion has been evaluated. Chemical Looping Combustion (CLC) is an innovative concept of CO2 capture from combustion of fossil fuels in power plants. CLC is closely related to oxy-fuel combustion as the chemically bound oxygen reacts in a stoichiometric ratio with the fuel. In CLC, the overall combustion takes place in two steps. In a reduction reactor fuel is oxidised by the oxygen carrier i.e. the metal oxide MeO which is reduced to metal oxide with a lower oxidation number, Me. Me flows to an oxidation reactor where it is oxidised by oxygen in the air. In this way pure oxygen is supplied to fuel without using an energy intensive traditional air separation unit. This paper presents thermodynamic cycle analysis of a CLC-power plant. A steady-state model has been developed for the solid-gas reactions occurring in the reactor system. The model is applied to analyse the system under two configurations; a combined cycle and a conventional steam cycle. A turbine-cooling model has also been implemented to evaluate the turbine cooling penalty in the combined cycle configuration. Effects of exhaust recirculation for coking prevention and incomplete fuel conversion have also been investigated. Performance of the oxygen carrier has been idealised except for the degrees of reduction and oxidation. Energy needs for CO2 capture have properly been taken into account. The results show that an optimum efficiency of 49.7% can be achieved under given conditions with a CLC-combined cycle at zero emissions level. With turbine cooling, efficiency falls by 1.2% points under the same conditions. The CLC-steam cycle is capable of achieving 40.1% efficiency with zero emissions. The results show that CLC has high potential for power generation with inherent CO2 capture. This work will be useful in designing CLC systems after the reactor system has been analysed experimentally for long-term operations.

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Inherent CO2 Capture Using Chemical Looping Combustion in a Natural Gas Fired Power Cycle

Volume 2: Turbo Expo 2002, Parts A and B ◽

10.1115/gt2002-30129 ◽

2002 ◽

Cited By ~ 3

Author(s):

O̸yvind Brandvoll ◽

Olav Bolland

Keyword(s):

Metal Oxide ◽

Co2 Capture ◽

Exergy Analysis ◽

Oxygen Carrier ◽

Fuel Combustion ◽

Chemical Looping Combustion ◽

Chemical Looping ◽

Conventional Combustion ◽

Oxidation Reactor ◽

Cycle Efficiency

In this paper an alternative to the so-called “oxy-fuel” combustion for CO2 capture is evaluated. “Chemical looping combustion” (CLC), is closely related to oxy-fuel combustion as the chemically bound oxygen reacts in a stoichiometric ratio with the fuel. In the CLC process the overall combustion reaction takes place in two reaction steps in two separate reactors. In the reduction reactor, the fuel is oxidised by the oxygen carrier, i.e. the metal oxide MeO. The metal oxide is reduced to a metal oxide with a lower oxidation number, Me, in the reaction with the fuel. In this manner, pure oxygen is supplied to the reaction with the fuel without using a traditional air separation plant, like cryogenic distillation of air. The paper presents a thermodynamic cycle analysis, where CLC is applied in a Humid Air Turbine concept. Main parameters are identified, and these are varied to examine the influence on cycle efficiency. Results on cycle efficiency are presented and compared to other CO2 capture options. Further, an evaluation of the oxygen carrier, metals/oxides, is presented. An exergy analysis is carried out in order to understand where losses occur, and to explain the difference between CLC and conventional combustion. The oxidation reactor air inlet temperature and the oxidation reactor exhaust temperature have a significant impact on the overall efficiency. This can be attributed to the controlling effect of these parameters on the required airflow rate. An optimum efficiency of 55.9% has been found for a given set of input parameters. Crucial issues of oxygen carrier durability, chemical performance and mechanical properties have been idealized, and further research on the feasibility of CLC is needed. Whether or not the assumption 100% gas conversion holds, is a crucial issue and remains to be determined experimentally. Successful long-term operation of chemical looping systems of this particular type has not yet been demonstrated. The simulation points out a very promising potential of CLC as a power/heat generating method with inherent capture of CO2. Exergy analysis show reduced irreversibilities for CLC compared to conventional combustion. Simulations of this type will prove useful in designing CLC systems in the future when promising oxygen carriers have been investigated in more detail.

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Bioethanol combustion with CO2 capture in a 1kWth Chemical Looping Combustion prototype: Suitability of the oxygen carrier

Chemical Engineering Journal ◽

10.1016/j.cej.2015.08.085 ◽

2016 ◽

Vol 283 ◽

pp. 1405-1413 ◽

Cited By ~ 16

Author(s):

L.F. de Diego ◽

A. Serrano ◽

F. García-Labiano ◽

E. García-Díez ◽

A. Abad ◽

...

Keyword(s):

Co2 Capture ◽

Oxygen Carrier ◽

Chemical Looping Combustion ◽

Chemical Looping

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Particulate Formation from a Copper Oxide-Based Oxygen Carrier in Chemical Looping Combustion for CO2 Capture

Environmental Science & Technology ◽

10.1021/acs.est.6b04043 ◽

2017 ◽

Vol 51 (4) ◽

pp. 2482-2490 ◽

Cited By ~ 15

Author(s):

Feng He ◽

William P. Linak ◽

Shuang Deng ◽

Fanxing Li

Keyword(s):

Copper Oxide ◽

Co2 Capture ◽

Oxygen Carrier ◽

Chemical Looping Combustion ◽

Chemical Looping

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A Parametric Study of Multi-Stage Chemical Looping Combustion for CO2 Capture Power Plant

Volume 2: Heat Transfer Enhancement for Practical Applications; Fire and Combustion; Multi-Phase Systems; Heat Transfer in Electronic Equipment; Low Temperature Heat Transfer; Computational Heat Transfer ◽

10.1115/ht2012-58597 ◽

2012 ◽

Cited By ~ 3

Author(s):

Bilal Hassan ◽

Tariq Shamim ◽

Ahmed F. Ghoniem

Keyword(s):

Power Plant ◽

Natural Gas ◽

Co2 Capture ◽

Waste Heat ◽

Oxygen Carrier ◽

Chemical Looping Combustion ◽

Chemical Looping ◽

Operating Pressure ◽

Efficiency Gain ◽

Multi Stage

A thermodynamic model and parametric analysis of a natural gas fired power plant with carbon dioxide (CO2) capture using multi-stage chemical looping combustion (CLC) are presented. CLC is an innovative concept and an attractive option to capture CO2 with a significantly lower energy penalty than other carbon-capture technologies. The principal idea behind CLC is to split the combustion process into two separate steps (redox reactions) carried out in two separate reactors: an oxidation reaction and a reduction reaction, by introducing suitable metal oxide which acts as an oxygen-carrier that circulates between the two reactors. In this study, an Aspen Plus model was developed by employing the conservation of mass and energy for all the components of the CLC system. In the analysis, equilibrium based thermodynamic reactions with no oxygen-carrier deactivation were considered. The model was employed to investigate the effect of various key operating parameters such as air, fuel and oxygen carrier (OC) mass flow rates, operating pressure, and waste heat recovery on the performance of a natural gas fired power plant with multi-stage CLC. Results of these parameters on the plant efficiency are presented. The analysis shows efficiency gain of more than 6% over that of conventional power plant with CO2 capture technologies when CLC is integrated with the power plant.

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