Mechanistic insights of CO2-coke reaction during the regeneration step of the fluid cracking catalyst

Santos, Luciana T. dos; Santos, Fabiana M.; Silva, Raphael S.; Gomes, Thiana S.; Esteves, Pierre M.; Pimenta, Ricardo D.M.; Menezes, Sônia Maria Cabral de; Chamberlain, O.; Lam, Yiu Lau; Pereira, Marcelo Maciel

doi:10.1016/j.apcata.2007.10.005

Cited by 30 publications

(17 citation statements)

References 17 publications

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“…These observations suggest that CO 2 preferentially reacts or interacts with unsaturated carbon bonds and oxygen reacts with aliphatic carbons causing the formation of water (it is not possible to speculate reaction pathway so far). Previously, it was shown using ex situ 13 C NMR of spent catalyst exposed to different TOS that aliphatic carbons are first consumed compared with more aromatic and more condensed carbons in coke . According to these results, under CO 2 /He flow, coke disproportionation into H 2 and condensed carbon is favored over RB reaction enabling hydrogen to be released as H 2 .…”

Section: Resultsmentioning

confidence: 96%

Catalyst regeneration using CO₂ as reactant through reverse‐Boudouard reaction with coke

et al. 2017

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The possibility of CO2 recycling into standard refinery can largely mitigate greenhouse gas emissions. It was previously demonstrated that alumina modified by either potassium or lithium in the presence of vanadium was able to promote the reaction of CO2 with coke in the presence of O2 during the regeneration step of a spent catalyst. Herein, vanadium‐sodium and vanadium‐calcium on alumina were used to achieve that reaction. These catalysts showed slightly lower conversion compared to previously catalysts. However, regardless of the type of group I and II elements, all catalysts showed very similar apparent activation energy (Eaapp) for the coke oxidation with CO2 reaction (CO2+coketo2.6pc→EaappCO+coke−O), i.e., in the range of 188–193 kJ.mol−1. In contrast without vanadium, Eaapp was in the range of 242–253 kJ.mol−1. Therefore, CO2 is activated in a site composed of V‐O‐(group I or II) in the coke proximity. Moreover, these results clearly support that vanadium plays the main role in the type of activation complex, independently of the group I and II metal used and most probably in the dissociative step of CO2. © 2017 Society of Chemical Industry and John Wiley & Sons, Ltd.

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Section: Resultsmentioning

confidence: 96%

Catalyst regeneration using CO₂ as reactant through reverse‐Boudouard reaction with coke

et al. 2017

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“…Oxyfuel combustion is another technology proposed to capture CO 2 from the FCC regenerator (Santos et al, 2008;Melien and Roijen, 2009;Mello et al, 2009aMello et al, , 2013Mello et al, , 2015aMiracca, 2015;Silva et al, 2015). High purity oxygen is used in the regenerator to produce a flue gas consisting of mainly CO 2 and H 2 O.…”

Section: Oxyfuel Combustionmentioning

confidence: 99%

“…In addition to the feasibility studies of oxyfuel combustion for FCC, Santos et al (2008) and Silva et al (2015), focused on the reactions occurred in the regenerator. Santos et al (2008) reported mechanistic insights of coke-CO 2 reactions in the regenerator. Coke functionality, especially aliphatic carbon, having much more influence on the CO 2 -coke reaction than O 2coke reaction.…”

Section: Oxyfuel Combustionmentioning

confidence: 99%

“…Boudouard reaction, 12 CO and 12 CO 2 are affected by catalyst types and reaction temperatures. During regeneration, besides CO 2 capture, the FCC process may have an important role to supply CO for other processes (Santos et al, 2008;Silva et al, 2015). A two-stage regenerator system was suggested, as presented in Figure 9 (Silva et al, 2015).…”

Section: Oxyfuel Combustionmentioning

confidence: 99%

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Progress in the CO2 Capture Technologies for Fluid Catalytic Cracking (FCC) Units—A Review

2020

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Heavy industries including cement, iron and steel, oil refining, and petrochemicals are collectively responsible for about 22% of global CO 2 emissions. Among these industries, oil refineries account for 4-6%, of which typically 25-35% arise from the regenerators in Fluid Catalytic Cracking (FCC) units. This article reviews the progress in applying CO 2 capture technologies to FCC units. Post combustion and oxyfuel combustion have been investigated to mitigate CO 2 emissions in FCC and, more recently, Chemical Looping Combustion (CLC) has received attention. Post combustion capture can readily be deployed to the flue gas in FCC units and oxyfuel combustion, which requires air separation has been investigated in a pilot-scale unit by Petrobras (Brazil). However, in comparison, CLC offers considerably lower energy penalties. The applicability of CLC for FCC has also been experimentally investigated at a lab-scale. As a result, the studies demonstrated highly promising CO 2 capture capacities for FCC with the application of post combustion (85-90%), oxyfuel combustion (90-100%) and CLC (90-96%). Therefore, the method having lowest energy penalty and CO 2 avoided cost is highly important for the next generation of FCC units to optimize CO 2 capture. The energy penalty was calculated as 3.1-4.2 GJ/t CO 2 with an avoiding cost of 75-110 e/t CO 2 for the application of post combustion capture to FCC. However, the application of oxyfuel combustion provided lower energy penalty of 1.8-2.5 GJ/t CO 2 , and lower CO 2 avoided cost of 55-85 e/t CO 2 . More recently, lab-scale experiments demonstrated that the application of CLC to FCC demonstrate significant progress with an indicative much lower energy penalty of ca. 0.2 GJ/t CO 2 .

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“…Sousa-Aguiar et al, 2005). A possibilidade de realizar a queima do coque na presença de CO 2 /O 2 ao invés de ar pode contribuir para atenuar as emissões do efeito estufa e, simultaneamente, produzir uma quantidade enorme de CO (R.T dos Santos et al, 2008). Ressalta-se que acima de 700 ºC, o equilíbrio termodinâmico é deslocado no sentido da formação de CO.…”

Section: Introductionunclassified

Catalisador De Vanádio-Potássio-Alumina: Uma Forma De Promover a Reação De Co2 E Coque Na Presença De O2 Durante a Regeneração Do Catalisador De FCC

Marques¹,

Silva²,

Santos³

et al. 2015

Anais Do XX Congresso Brasileiro De Engenharia Química

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RESUMO -O processo de craqueamento catalítico em leito fluidizado (FCC) é responsável por cerca de 30% das emissões de CO 2 na refinaria. Tendo essa perspectiva, a proposta deste trabalho é estudar a possibilidade de queima do coque em atmosfera CO 2 /O 2 ao invés de ar como é correntemente utilizado na refinaria. A reação do CO 2 com o coque pode ser muito relevante, pois simultaneamente minimizaria as emissões e ainda produziria como produto o CO, que é uma molécula estratégica do ponto de vista industrial. Os resultados mostraram que os catalisadores de alumina contendo potássio e vanádio são potenciais para a reação do CO 2 com o coque, pois permitiram realizar esta reação com grande conversão e ainda na presença de oxigênio. Foi claramente mostrado uma sinergia entre potássio e vanádio. Desta forma, os resultados demonstraram que na etapa de regeneração do catalisador, o equilíbrio térmico pode ser mantido, assim como possibilita produção de CO, quanto mitigação de CO 2 .

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Mechanistic insights of CO2-coke reaction during the regeneration step of the fluid cracking catalyst

Cited by 30 publications

References 17 publications

Catalyst regeneration using CO₂ as reactant through reverse‐Boudouard reaction with coke

Catalyst regeneration using CO₂ as reactant through reverse‐Boudouard reaction with coke

Progress in the CO2 Capture Technologies for Fluid Catalytic Cracking (FCC) Units—A Review

Catalisador De Vanádio-Potássio-Alumina: Uma Forma De Promover a Reação De Co2 E Coque Na Presença De O2 Durante a Regeneração Do Catalisador De FCC

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Mechanistic insights of CO2-coke reaction during the regeneration step of the fluid cracking catalyst

Cited by 30 publications

References 17 publications

Catalyst regeneration using CO2 as reactant through reverse‐Boudouard reaction with coke

Catalyst regeneration using CO2 as reactant through reverse‐Boudouard reaction with coke

Progress in the CO2 Capture Technologies for Fluid Catalytic Cracking (FCC) Units—A Review

Catalisador De Vanádio-Potássio-Alumina: Uma Forma De Promover a Reação De Co2 E Coque Na Presença De O2 Durante a Regeneração Do Catalisador De FCC

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Catalyst regeneration using CO₂ as reactant through reverse‐Boudouard reaction with coke

Catalyst regeneration using CO₂ as reactant through reverse‐Boudouard reaction with coke