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

2004 ◽  
Vol 126 (2) ◽  
pp. 316-321 ◽  
Author(s):  
O̸. Brandvoll ◽  
O. 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 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 .

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

2002 ◽  
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.

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

2004 ◽  
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.

scholarly journals Exergy Analysis of Gas Switching Chemical Looping IGCC Plants

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 544 ◽  
Author(s):  
Carlos Arnaiz del Pozo ◽  
Ángel Jiménez Álvaro ◽  
Jan Hendrik Cloete ◽  
Schalk Cloete ◽  
Shahriar Amini
Keyword(s):  
Co2 Capture ◽  
Exergy Analysis ◽  
High Efficiency ◽  
Oxygen Carrier ◽  
Scale Up ◽  
Air Separation ◽  
Chemical Looping ◽  
Oxygen Carriers ◽  
Constant Flow Rate ◽  
Oxidation Reactor

Integrated gasification combined cycles (IGCC) are promising power production systems from solid fuels due to their high efficiency and good environmental performance. Chemical looping combustion (CLC) is an effective route to reduce the energy penalty associated with CO2 capture. This concept comprises a metal oxygen carrier circulated between a reduction reactor, where syngas is combusted, and an oxidation reactor, where O2 is withdrawn from an air stream. Parallel to CLC, oxygen carriers that are capable of releasing free O2 in the reduction reactor, i.e., chemical looping oxygen production (CLOP), have been developed. This offers interesting integration opportunities in IGCC plants, replacing energy demanding air separation units (ASU) with CLOP. Gas switching (GS) reactor cluster technology consists of a set of reactors operating in reduction and oxidation stages alternatively, providing an averaged constant flow rate to the gas turbine and a CO2 stream readily available for purification and compression, and avoiding the transport of solids across reactors, which facilitates the scale up of this technology at pressurized conditions. In this work, exergy analyses of a gas switching combustion (GSC) IGCC plant and a GSOP–GSC IGCC plant are performed and consistently benchmarked against an unabated IGCC and a precombustion CO2 capture IGCC plant. Through the exergy analysis methodology, an accurate assessment of the irreversible loss distribution in the different power plant sections from a second-law perspective is provided, and new improvement pathways to utilize the exergy contained in the GSC reduction gases outlet are identified.

CuO promoted Mn2O3-based materials for solid fuel combustion with inherent CO2 capture

2015 ◽  
Vol 3 (19) ◽  
pp. 10545-10550 ◽  
Author(s):  
D. Hosseini ◽  
Q. Imtiaz ◽  
P. M. Abdala ◽  
S. Yoon ◽  
A. M. Kierzkowska ◽  
...  
Keyword(s):  
Co2 Capture ◽  
Solid Fuel ◽  
Oxygen Carrier ◽  
Fuel Combustion ◽  
Chemical Looping ◽  
Solid Fuel Combustion

A novel bimetallic Cu–Mn oxygen carrier for Chemical-Looping with Oxygen Uncoupling (CLOU) based CO2 capture.

Three Reactors Chemical Looping Combustion for High Efficiency Electricity Generation With CO2 Capture From Natural Gas

2006 ◽  
Author(s):  
Giovanni Lozza ◽  
Paolo Chiesa ◽  
Matteo Romano ◽  
Paolo Savoldelli
Keyword(s):  
Natural Gas ◽  
Metal Oxide ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Specific Power ◽  
Working Fluid ◽  
Chemical Looping Combustion ◽  
Chemical Looping ◽  
Water Separation ◽  
Oxidation Reactor

Chemical-Looping Combustion (CLC) is a process where fuel oxidation is accomplished by the oxygen carried by a metal oxide, circulating across two reactors: a reduction reactor (reducing the metal oxide by oxidizing the natural gas fuel) and an oxidation reactor (re-oxidizing the metal by reacting with air, a strongly exothermic reaction). The system produces: (i) a stream of oxidation products (CO2 and H2O), ready for carbon sequestration after water separation and CO2 liquefaction; (ii) a stream of hot air (deprived of some oxygen) used as working fluid of a gas turbine cycle. Due to the moderate temperature (∼850°C) of this stream, sensibly lower than those adopted in commercial gas turbines, the combined cycle arranged around this concept suffers from poor conversion efficiency and, therefore, economics. In the present paper, the basic CLC arrangement is modified by inserting a third reactor in the loop. This reactor, by exploiting an intermediate oxidation state of the circulating metal, produces H2 used as decarbonized fuel to raise the temperature of the air coming from the oxidation reactor, up to the highest value allowed by the modern gas turbine technology (∼1350°C), thus achieving elevated efficiency and specific power output. This paper is aimed to assess the potential of power cycles based on the three reactors (CLC3) arrangement. More specifically, we will discuss the plant configuration, the process optimization and the performance prediction. Results show that the CLC3 system is very promising: the net LHV efficiency of the best configuration exceeds 51%, an outstanding figure for a natural gas power cycle producing liquid, disposal-ready CO2 and negligible NOx emissions. Commercial gas turbines can be easily adapted to operate in the specific conditions of the CLC3 arrangement which, apart from the reactors system, does not require the development of novel technologies and/or high-risk components. The paper also reports a final comparison with a rival technology based on natural gas partial oxidation, water-gas shift reaction and CO2 separation by MDEA absorption. This work has been performed within the research on the Italian Electrical System “Ricerca di Sistema”, Ministerial Decrees of January 26 – 2000, and April 17 – 2001.

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

2016 ◽  
Vol 283 ◽  
pp. 1405-1413 ◽  
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

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

2018 ◽  
Vol 51 (18) ◽  
pp. 97-102 ◽  
Author(s):  
Huabei You ◽  
Yue Yuan ◽  
Jingde Li ◽  
Luis Ricardez Sandoval
Keyword(s):  
Co2 Capture ◽  
Oxygen Carrier ◽  
Scale Model ◽  
Chemical Looping Combustion ◽  
Chemical Looping ◽  
Multi Scale

Chemical-Looping Combustion for Combined Cycles With CO2 Capture

2006 ◽  
Vol 128 (3) ◽  
pp. 525-534 ◽  
Author(s):  
Stefano Consonni ◽  
Giovanni Lozza ◽  
Giampaolo Pelliccia ◽  
Stefano Rossini ◽  
Francesco Saviano
Keyword(s):  
Metal Oxide ◽  
Gas Turbines ◽  
Exothermic Reaction ◽  
Combined Cycle ◽  
Oxidation Products ◽  
Chemical Looping Combustion ◽  
Excess Oxygen ◽  
Chemical Looping ◽  
Combined Cycles ◽  
Oxidation Reactor

Chemical-Looping Combustion (CLC) is a process where fuel oxidation is carried out through an intermediate agent—a metal oxide—circulated across two fluidized bed reactors: a reduction reactor, where an endothermic reaction reduces the metal oxide and oxidizes the fuel, and an oxidation reactor, where an exothermic reaction oxidizes the metal oxide in air. Overall, the system carries out the same job of a conventional combustor, with the fundamental advantage of segregating the oxidation products (CO2 and H2O) into an output flow free of nitrogen and excess oxygen. The flow exiting the reduction reactor consists of water and CO2, the latter readily available for liquefaction, transport and long-term storage. The hot, vitiated air from the oxidation reactor is the means to produce power through a thermodynamic cycle. This paper reports of a study supported by the ENI group to assess the potential of the integration between CLC and combined gas-steam power cycles. More specifically, we focus on four issues: (i) optimization of plant configuration; (ii) prediction of overall efficiency; (iii) use of commercial gas turbines; (iv) preliminary economic estimates. The CLC system is based on iron oxides which, to maintain their physical characteristics, must operate below 900–1000°C. Given the crucial importance of the temperature of the vitiated air generated by CLC on the performance of the combined cycle, we consider two options: (i) “unfired” systems, where natural gas is fed only to the CLC system, (ii) “fired” systems, where the vitiated air is supplementary fired to reach gas turbine inlet temperatures ranging 1000–1200°C. Results show that unfired configurations with maximum process temperature 850–1050°C and zero emissions reach net LHV plant efficiencies ranging 43%–48%. Fired cycles where temperature is raised from 850 to 1200°C by supplementary firing can achieve 52% net LHV efficiency with CO2 emission about one half of those of a state-of-the-art combined cycles. Fired configurations allow significant capital cost and fuel cost savings compared to unfired configurations; however, a carbon tax high enough to make them attractive (close to 50 €/ton) would undermine these advantages.

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