CO2 multicyclic capture of pretreated/doped CaO in the Ca-looping process. Theory and experiments

Valverde, José Manuel; Jiménez, Pilar; Pérez‐Maqueda, Luis A.

doi:10.1039/c3cp50480h

Cited by 45 publications

(31 citation statements)

References 53 publications

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“…99,100 TGA tests involving calcination at 950ºC under low CO 2 concentration show that multicyclic CaO conversion decays with the cycle number and converges to a residual value X r = 0.07-0.08. 21,92,101,102 The presence of CO 2 at high concentration in the calcination environment produces a significantly marked drop of conversion for CaO derived from limestone precalcined in air, with values around 0.05 after few cycles. 33,89,90,103 It has been proposed that a progressive growth of the regenerated crystal structure along preferential surfaces, which are more stable but less favorable for CaCO 3 nucleation, could play a role on the loss of multicyclic CaO conversion.…”

Section: The Multicyclic Co2 Capture Capacity Of Natural Limestone Atmentioning

confidence: 99%

The Calcium-Looping technology for CO2 capture: On the important roles of energy integration and sorbent behavior

et al. 2016

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The Calcium Looping (CaL) technology, based on the multicyclic carbonation/calcination of CaO in gassolid fluidized bed reactors at high temperature, has emerged in the last years as a potentially low cost technology for CO 2 capture. In this manuscript a critical review is made on the important roles of energy integration and sorbent behavior in the process efficiency. Firstly, the strategies proposed to reduce the energy demand by internal integration are discussed as well as process modifications aimed at optimizing the overall efficiency by means of external integration. The most important benefit of the high temperature CaL cycles is the possibility of using high temperature streams that could reduce significantly the energy penalty associated to CO 2 capture. The application of the CaL technology in precombustion capture systems and energy integration, and the coupling of the CaL technology with other industrial processes are also described. In particular, the CaL technology has a significant potential to be a feasible CO 2 capture system for cement plants. A precise knowledge of the multicyclic CO 2 capture behavior of the sorbent at the CaL conditions to be expected in practice is of great relevance in order to predict a realistic efficiency from process simulations. The second part of this manuscript will be devoted to this issue. Particular emphasis is put on the behavior of natural limestone and dolomite, which would be the only practical choices for the technology to meet its main goal of reducing CO 2 capture costs. Under CaL calcination conditions for CO 2 capture (necessarily implying high CO 2 concentration in the calciner), dolomite seems to be a better alternative to limestone as CaO precursor. The proposed techniques of recarbonation and thermal/mechanical pretreatment to reactivate the sorbent and accelerate calcination will be the final subjects of this review.

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Section: The Multicyclic Co2 Capture Capacity Of Natural Limestone Atmentioning

confidence: 99%

The Calcium-Looping technology for CO2 capture: On the important roles of energy integration and sorbent behavior

et al. 2016

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“…In general, it may be seen that CaO conversion in the FR phase is relatively small as compared to conversion in the SD phase. As reported in previous works [10][11], calcination under high CO 2 partial pressure yields a highly sintered CaO structure with a quite reduced surface area available for fast reaction controlled carbonation, which severely hampers carbonation in this initial phase. On the other hand, the diffusion controlled stage is relatively promoted.…”

Section: Co Capture Capacitymentioning

confidence: 60%

“…On one hand, it poses an energy penalty for the technology [8][9]. On the other, it causes a marked aggregation and sintering of the CaO nascent grains during the CaCO 3 /CaO transformation, which leads to a drastic decrease of the CaO surface area available for quick carbonation in a subsequent cycle [10][11]. As demonstrated in previous studies [12], carbonation of CaO particles takes place through two different phases.…”

Section: Introductionmentioning

confidence: 80%

“…Thus, the values of capture capacity for this sorbent are higher from the th cycle as compared to those obtained for the sorbent directly derived from natural dolomite calcination when a recarbonation stage is introduced. Multicycle capture capacity data obtained from the TGA tests were fitted using the semi-empirical equation [11,[45][46]:…”

Section: Co Capture Capacitymentioning

confidence: 99%

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CO2 capture performance of Ca-Mg acetates at realistic Calcium Looping conditions

Miranda-Pizarro

Perejón

Valverde

et al. 2017

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The Calcium Looping (CaL) process, based on the cyclic carbonation/calcination of CaO, has emerged in the last years as a potentially low cost technique for CO 2 capture at reduced energy penalty. In the present work, natural limestone and dolomite have been pretreated with diluted acetic acid to obtain Ca and Ca-Mg mixed acetates, whose CO 2 capture performance has been tested at CaL conditions that necessarily imply sorbent regeneration under high CO 2 partial pressure. The CaL multicycle capture performance of these sorbents has been compared with that of CaO directly derived from limestone and dolomite calcination. Results show that acetic acid pretreatment of limestone does not lead to an improvement of its capture capacity, although it allows for a higher calcination efficiency to regenerate CaO at reduced temperatures (~900ºC) as compared to natural limestone (>~930ºC). 3 On the other hand, if a recarbonation stage is introduced before calcination to reactivate the sorbent, a significantly higher residual capture capacity is obtained for the Ca-Mg mixed acetate derived from dolomite as compared to either natural dolomite or limestone. The main reason for this behavior is the enhancement of carbonation in the solid-state diffusion controlled phase. It is argued that the presence of inert MgO grains in the mixed acetate with reduced segregation notably promotes solid state diffusion of ions across the porous structure created after recarbonation.

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“…The carbonator temperature is maintained between 580-700 °C, which is the optimal capture temperature range due to the trade-off between the equilibrium forces and the reaction kinetics [24,25]. The calcination occurs at more than 900 °C, in a chamber that is modelled as a Gibbs reactor, where extra fuel is burned in an O 2 /CO 2 atmosphere to generate heat required for the endothermic calcination reaction [14,26]. As the sorbent conversion decreases during the carbonation/calcination cycles, the fresh sorbent make-up is considered.…”

Section: Capture Plantmentioning

confidence: 99%

Process modelling and techno-economic analysis of natural gas combined cycle integrated with calcium looping

et al. 2016

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Calcium looping is promising for large-scale CO 2 capture in the power generation and industrial sectors due to the cheap sorbent used and the relatively low energy penalties achieved with this process. Because of the high operating temperatures the heat utilisation is a major advantage of the process, since a significant amount of additional power can be generated from it. However, this increases its complexity and capital costs. Therefore, not only the energy efficiency performance is important for these cycles, but also the capital costs must be taken into account, i. e. techno-economic analyses are required in order to determine which parameters and configurations are optimal to enhance technology viability in different integration scenarios. In this study the integration scenarios of calcium looping and natural gas combined cycles are explored. The process models of the natural gas combined cycles and calcium looping CO 2 capture plant are developed to explore the most promising scenarios for natural gas combined cycles-calcium looping integration with regard to efficiency penalties. Two scenarios are analysed in detail, and show that the system with heat recovery steam generator before and after the capture plant exhibited better performance of 49.1% efficiency compared with that of 45.7% when only one heat recovery steam generator is located after the capture plant. However, the techno-economic analyses showed that the more energy efficient case, with two heat recovery steam generators, implies relatively higher cost of electricity, 44.1 €/MWh, when compared to that of the reference plant system (33.1 €/MWh). The predicted cost of CO 2 avoided for the case with two heat recovery steam generators is 29.3 € per tonne of CO 2 .

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CO2 multicyclic capture of pretreated/doped CaO in the Ca-looping process. Theory and experiments

Cited by 45 publications

References 53 publications

The Calcium-Looping technology for CO2 capture: On the important roles of energy integration and sorbent behavior

The Calcium-Looping technology for CO2 capture: On the important roles of energy integration and sorbent behavior

CO2 capture performance of Ca-Mg acetates at realistic Calcium Looping conditions

Process modelling and techno-economic analysis of natural gas combined cycle integrated with calcium looping

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