A new model of the carbonator reactor in the calcium looping technology for post-combustion CO2 capture

Ortíz, C.; Chacartegui, Ricardo; Becerra, J. A.; Pérez‐Maqueda, Luis A.

doi:10.1016/j.fuel.2015.07.095

Cited by 49 publications

(34 citation statements)

References 47 publications

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“…That crystal growth results in slower decarbonation kinetics as can be observed in Figure 2a This enhanced decarbonation kinetics constitutes an important advantage since, given the limited lifetime of the makeup flow of fresh material fed into the calciner, it is of paramount importance to maximize the CaO carbonation reactivity from the first cycle at a reduced calcination temperature. As seen in our work this is possible for dolomite by operating the calciner at 900ºC whereas in the case of limestone the calciner temperature has to be increased up to 930-950ºC, which enhances further CaO deactivation [48].…”

Section: Influence Of Crystal Growth and Sintering On Cao Conversionmentioning

confidence: 84%

Effect of dolomite decomposition under CO₂ on its multicycle CO₂ capture behaviour under calcium looping conditions

Martos

Valverde

Jiménez

et al. 2016

Phys. Chem. Chem. Phys.

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One of the main drawbacks that hinder the industrial competitiveness of the Calcium Looping (CaL) process for CO 2 capture is the high temperatures (~930-950ºC) needed in practice to attain full calcination of limestone under a high CO 2 partial pressure environment for short residence times as required in practice. In this work, the multicycle CO 2 capture performance of dolomite and limestone is analysed under realistic CaL conditions and using a reduced calcination temperature of 900ºC, which would serve to mitigate the energy penalty caused by integrating the CaL process into fossil fuel fired power plants. The results show that the fundamental mechanism of dolomite decomposition under CO 2 has a main influence on its superior performance compared to limestone. The inert MgO grains resulting from dolomite decomposition help preserving a nanocrystalline CaO structure wherein carbonation in the solid-state diffusion controlled phase is promoted. The major role played by dolomite decomposition mechanism under CO 2 is clearly demonstrated by the multicycle CaO conversion behaviour observed for samples decomposed at different preheating rates. Limestone decomposition at slow heating rates yields a highly crystalline and poorly reactive CaCO 3 structure that requires long periods to fully decarbonate and shows a severely reduced capture capacity in subsequent cycles. On the other hand, the nascent CaCO 3 produced after dolomite half-decomposition consists of nanosized crystals with a fast decarbonation kinetics regardless of the preheating rate, thus fully decomposing from the very first cycle at a reduced calcination temperature into a CaO skeleton with enhanced reactivity as compared to limestone derived CaO.

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Section: Influence Of Crystal Growth and Sintering On Cao Conversionmentioning

confidence: 84%

Effect of dolomite decomposition under CO₂ on its multicycle CO₂ capture behaviour under calcium looping conditions

Martos

Valverde

Jiménez

et al. 2016

Phys. Chem. Chem. Phys.

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“…One of the main drawbacks of the CaL process is the progressive loss of activity of CaO particles at short residence times as the number of carbonation/calcination cycles is increased. This is especially true for limestone‐derived CaO at CaL conditions corresponding to post‐combustion CO 2 capture because of the enhanced sintering of the CaO grains. Enhanced sintering during the CaCO 3 /CaO transformation drastically reduces the active surface of the solids in the reaction‐controlled fast phase that takes place in the first seconds of carbonation .…”

Section: Multicycle Co2 Capture Behavior Of Limestone Dolomite and Smentioning

confidence: 99%

“…Here we briefly summarize the kinetic model developed elsewhere in which the relevant contribution of carbonation in the SDP, as described above, is explicitly considered . The model is used to describe the multicycle CO 2 capture capacity of limestone‐, dolomite‐, and steel slag‐derived sorbents.…”

Section: Multicycle Co2 Capture Behavior Of Limestone Dolomite and Smentioning

confidence: 99%

“…in which [CO 2 ] and [CO 2 ] eq are the actual and equilibrium CO 2 concentrations, respectively, k s is the kinetic constant, CC max is the maximum CO 2 capture capacity, and S N is the sorbent specific area available for reaction after N cycles, which is proportional to the capture capacity degree. The rate of capture capacity in the diffusion‐controlled phase can be expressed by using an effective diffusion constant ( D * eff )

true r_{N_{S D P}} \approx {D^{*}}_{normale normalf normalf} (() [normalC O_{2}] - {([], C, {normalO}_{2})}_{e q})

…”

Section: Multicycle Co2 Capture Behavior Of Limestone Dolomite and Smentioning

confidence: 99%

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Energy Consumption for CO₂ Capture by means of the Calcium Looping Process: A Comparative Analysis using Limestone, Dolomite, and Steel Slag

Ortíz

Chacartegui

2016

Energy Tech

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The calcium looping (CaL) process, based upon the dry carbonation/calcination of CaO/CaCO3, is at the center of a potentially low‐cost, second‐generation technology for CO2 capture. This manuscript analyzes the energy penalty that arises from the integration of the CaL process into a coal‐fired power plant using cheap and abundantly available CaO precursors such as natural limestone, dolomite, and steel slag. Experimental results on their multicycle capture capacity behavior obtained from thermogravimetric analysis (TGA) at realistic CaL conditions for CO2 capture are used to this end. This work shows that the specific energy consumption for CO2 avoided (SPECCA) is reduced by using either dolomite or steel slag, whose carbonation kinetics in the diffusive phase are accelerated as compared to limestone. Thus, the use of dolomite as CaO precursor would yield a low SPECCA value of approximately 2 MJ kg−1 CO2 for a residence time of the solids in the carbonator of approximately 10 minutes, which is clearly below the SPECCA value usually reported for conventional amine‐based CO2 capture systems.

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“…Once CO 2 is captured in the carbonator and heat from the exothermic reaction is recovered, the almost CO 2 free flue gas is released into the atmosphere. Several carbonator reactor models have been developed to predict the CO 2 capture efficiency as depending on operating conditions and CaO multicycle conversion under CaL conditions for CO 2 capture [29][30][31]. These involve carbonation under relatively low CO 2 partial pressure (about 0.15 atm) and calcination at very high temperatures (around 950ºC) under high CO 2 partial pressure with short residence times at both stages.…”

Section: Introductionmentioning

confidence: 99%

Thermochemical energy storage of concentrated solar power by integration of the calcium looping process and a CO2 power cycle

et al. 2016

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Energy storage is the main challenge for a deep penetration of renewable energies into the grid to overcome their intrinsic variability. Thus, the commercial expansion of renewable energy, particularly wind and solar, at large scale depends crucially on the development of cheap, efficient and non-toxic energy storage systems enabling to supply more flexibility to the grid. The Ca-Looping (CaL) process, based upon the reversible carbonation/calcination of CaO, is one of the most promising technologies for thermochemical energy storage (TCES), which offers a high potential for the long-term storage of energy with relatively small storage volume. This manuscript explores the use of the CaL process to store Concentrated Solar Power (CSP). A CSP-CaL integration scheme is proposed mainly characterized by the use of a CO 2 closed loop for the CaL cycle and power production, which provides heat decoupled from the solar source and temperatures well above the ~550ºC limit that poses the use of molten salts currently used to store energy as sensible heat. The proposed CSP-CaL integration leads to high values of plant global efficiency (of around 45-46%) with a storage capacity that allows for long time gaps between load and discharge. Moreover, the use of environmentally benign, abundantly available and cheap raw materials such as natural limestone would mark a milestone on the road towards the industrial competitiveness of CSP.

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A new model of the carbonator reactor in the calcium looping technology for post-combustion CO2 capture

Abstract: The Ca-Looping (CaL) process is considered as a promising technology for CO 2 post-combustion capture in power

Cited by 49 publications

References 47 publications

Effect of dolomite decomposition under CO₂ on its multicycle CO₂ capture behaviour under calcium looping conditions

Effect of dolomite decomposition under CO₂ on its multicycle CO₂ capture behaviour under calcium looping conditions

Energy Consumption for CO₂ Capture by means of the Calcium Looping Process: A Comparative Analysis using Limestone, Dolomite, and Steel Slag

Thermochemical energy storage of concentrated solar power by integration of the calcium looping process and a CO2 power cycle

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A new model of the carbonator reactor in the calcium looping technology for post-combustion CO2 capture

Abstract: The Ca-Looping (CaL) process is considered as a promising technology for CO 2 post-combustion capture in power

Cited by 49 publications

References 47 publications

Effect of dolomite decomposition under CO2 on its multicycle CO2 capture behaviour under calcium looping conditions

Effect of dolomite decomposition under CO2 on its multicycle CO2 capture behaviour under calcium looping conditions

Energy Consumption for CO2 Capture by means of the Calcium Looping Process: A Comparative Analysis using Limestone, Dolomite, and Steel Slag

Thermochemical energy storage of concentrated solar power by integration of the calcium looping process and a CO2 power cycle

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Resources

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Effect of dolomite decomposition under CO₂ on its multicycle CO₂ capture behaviour under calcium looping conditions

Effect of dolomite decomposition under CO₂ on its multicycle CO₂ capture behaviour under calcium looping conditions

Energy Consumption for CO₂ Capture by means of the Calcium Looping Process: A Comparative Analysis using Limestone, Dolomite, and Steel Slag