Study of a Cu-CuO chemical loop for the calcination of CaCO3 in a fixed bed reactor

Alarcón, Juana M.; Fernández, José R.; Abanades, J.C.

doi:10.1016/j.cej.2017.05.070

Cited by 30 publications

(28 citation statements)

References 68 publications

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“…From t=2 min to t=4 min, the conversion of CH 4 is almost completely achieved. From that point onwards, the CH 4 in the product gas progressively rises during a long breakthrough period (until t<25 min), which demonstrates that the reactivity of CH 4 with CuO is significantly lower than that of H 2 and CO with the same oxygen carrier (as described in [48,49]). A small amount of CO (i.e., below 3 vol.%) is present in the product gas during the first minutes of the breakthrough period.…”

Section: Resultsmentioning

confidence: 88%

“…Both materials exhibited excellent performances after repetitive oxidation-reductionreforming cycles. Alarcón et al [48] showed that the dilution of the O 2 in the feed by simulating the recirculation of a large part of the product gas (virtually pure N 2 ) allows the maximum temperature achieved during the Cu oxidation to be kept below 800 ºC, which would minimize the calcination of the Ca-based sorbent during the operation.…”

Section: Introductionmentioning

confidence: 99%

“…Finally, the calcination of CaCO 3 by means of the in situ CuO reduction was also studied using mixtures of H 2 and CO as fuel gas [48,49].…”

Section: Introductionmentioning

confidence: 99%

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Study of the calcination of CaCO3 by means of a Cu/CuO chemical loop using methane as fuel gas

2019

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The Ca-Cu looping process allows a H 2-rich product gas to be obtained on the basis of the sorption enhanced reforming (SER) concept, while generating a concentrated stream of CO 2 suitable for geological storage or industrial use. Previous works have demonstrated that the Cu/CuO chemical loop provides a feasible alternative for regenerating the CO 2-sorbent required for the SER with potentially low energy penalties. In this work, the CuO reduction/CaCO 3 calcination operation, which is the key stage of the Ca-Cu looping process, is experimentally demonstrated in a fixed-bed reactor at TRL4 using pure methane as fuel gas. The effect of the temperature of the solids bed on the operation is also evaluated. A detailed characterization of both CuOand CaO-based materials resulting from the experiments has been carried out, revealing only minor changes in their textural properties, which demonstrates their high stability after successive oxidation-carbonation-reduction/calcination cycles.

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Section: Resultsmentioning

confidence: 88%

Section: Introductionmentioning

confidence: 99%

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Study of the calcination of CaCO3 by means of a Cu/CuO chemical loop using methane as fuel gas

2019

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“…The maximum temperature during Cu oxidation must be kept below 1173 K to minimize the calcination of CaCO 3 and the temperature profiles can be moderated by decreasing the concentration of the oxygen in the feed and the temperature of the inlet gas. Finally, the step C of the process has been evaluated in an adiabatic fixed bed using a dynamic pseudo-homogeneous model [23] and has been experimentally validated under industrially relevant conditions for this technology [24]. A sensitivity analysis of the main parameters involved in the process confirmed the viability of this step and an optimal CuO/CaCO 3 ratio ensured a suitable bed performance allowing that the calcination and reduction fronts advance together at moderate temperatures (1173 K) and leaving behind fully conversion of the materials.…”

Section: Introductionmentioning

confidence: 99%

Determination of the oxidation kinetics of high loaded CuO-based materials under suitable conditions for the Ca/Cu H2 production process

Díez-Martín

Grasa

Murillo

et al. 2018

Fuel

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In this work, the oxidation reaction of high loaded CuO-based materials was investigated under atmospheric and pressurized conditions. The oxygen transport capacity of the materials was firstly tested in the TGA and no losses greater than 5% were observed along 100 oxidation/reduction cycles. The kinetic parameters governing the oxidation reactions of the selected CuO-based materials were determined using a shrinking core model with chemical reaction control. The experimental results suggested that a SCM with chemical reaction control is able to predict the oxidation conversion of high loaded CuO-based materials in powder and pellet form. On the other hand, the effect of total pressure on materials reactivity was analyzed. The kinetic parameters obtained under atmospheric conditions were applied to fit the experimental data obtained under pressurized conditions. The results confirmed that the pressure has not an important effect on the oxidation kinetics of high loaded CuO-based materials and the parameters obtained at atmospheric pressure can be applied to study the oxidation under pressurized conditions.

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“…The initial works presented the conceptual design of the process [11,14] and relevant works have been focused on reactor modelling [7,[15][16][17] and process integration [18][19][20][21] to demonstrate the implementation of the concept on large-scale H 2 production process. Reaction stages involving Ca and Cu solids have been experimentally studied at laboratory scale [22,23] and simultaneous CuO reduction/CaCO3 calcination up to TRL4 [24]. The experimental studies on SER stage under relevant conditions of the process are currently scarce nevertheless high H2 production efficiencies have been corroborated for a mixture of CO2-sorbent with fresh or aged reforming catalyst at different mass hourly space velocities and pressures [25].…”

Section: Introductionmentioning

confidence: 99%

Catalyst evaluation for high-purity H2 production by sorption-enhanced steam-methane reforming coupled to a Ca/Cu process

Navarro

López

Garcı́a

et al. 2017

Journal of Power Sources

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The operational limits of a commercial nickel-based catalyst under the conditions of a sorption-enhanced steam-methane reforming process coupled to a Ca/Cu chemical loop are investigated for high-purity H 2 production in a cyclic operation. The performance of the reforming catalyst is tested by means of a high number of oxidation-reductionreforming cycles. After 100 oxidation-reduction cycles, this catalyst retains its exceptional reforming activity. The methane conversion values are close to the thermodynamic equilibrium under very demanding conditions: temperature between 500 ºC-700 ºC and mass hourly space velocity of 8.8 kgCH 4 h-1 kgcat-1. After 200 cycles, the sample shows reduction in its reforming activity in line with a lower dispersion of the Ni species. Sintering of Ni nanocrystals is evidenced during the oxidation-reduction multi-cycles. The performance of the catalyst after 200 oxidationreduction cycles mixed with a CaO-based CO 2 sorbent is studied under optimal conditions calculated for the sorption-enhanced reforming process coupled to a Ca/Cu cycle (temperature of 650 ºC, steam/methane ratio of 4, sorbent/catalyst ratio of 4 and space velocity of 0.75 kgCH 4 h-1 kgcat-1). Remarkably, an equilibrium value over 92 vol.% H 2 concentration is achieved, highlighting this catalyst as a promising candidate for the next steps of the process development.

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Study of a Cu-CuO chemical loop for the calcination of CaCO3 in a fixed bed reactor

Cited by 30 publications

References 68 publications

Study of the calcination of CaCO3 by means of a Cu/CuO chemical loop using methane as fuel gas

Study of the calcination of CaCO3 by means of a Cu/CuO chemical loop using methane as fuel gas

Determination of the oxidation kinetics of high loaded CuO-based materials under suitable conditions for the Ca/Cu H2 production process

Catalyst evaluation for high-purity H2 production by sorption-enhanced steam-methane reforming coupled to a Ca/Cu process

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