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- Fixed bed adsorption of CO2, CH4, and N2 and their mixtures in potassium-exchanged binder-free beads of Y zeolitePublication . Aly, Ezzeldin; Zafanelli, Lucas F.A.S.; Henrique, Adriano; Pires, Marcella Golini; Rodrigues, Alírio; Gleichmann, Kristin; Silva, José A.C.; Pires, Marcella GoliniThe adsorption of carbon dioxide (CO2), methane (CH4), and nitrogen (N2) has been studied on potassium-exchanged (95%) binder-free beads of Y zeolite through single, binary, and ternary fixed bed breakthrough experiments, covering the temperature range between 313 and 423 K and a pressure of up to 350 kPa. At 313 K and 350 kPa, the single-component data obtained showed that the amounts adsorbed of CO2, CH4, and N2 are around 6.42, 1.45, and 0.671 mol kg-1, respectively. The binary experiments CO2/N2 carried out under typical post-combustion conditions show a selectivity of CO2 over N2 around 104. The ternary experiments resulted in the selectivities of CO2 over CH4 and N2 around 19 and 45, respectively. The adsorption equilibrium data have been modeled by the dual-site Langmuir model, and the breakthrough experiments were numerically simulated with a suitable dynamic fixed bed adsorption model. The model predicts with good accuracy the systematic behavior of all breakthrough experiments. The results shown in the present work prove that the potassium-exchanged binder-free beads of Y zeolite enhance the amount adsorbed of CO2 at low partial pressure over other alkali metal-exchanged faujasites and efficiently separate it from binary (CO2/N2) and ternary (CO2/CH4/N2) mixtures by fixed bed adsorption.
- Novel insights into activated carbon derived from municipal solid waste for CO2 uptake: synthesis, adsorption isotherms and scale-upPublication . Karimi, Mohsen; Zafanelli, Lucas F.A.S.; Almeida, João P.; Ströher, Gylles R.; Rodrigues, Alírio; Silva, José A.C.Recently, developing bio-based carbon materials due to the surface chemistry and a large spectrum of pore structures have received much attention. In the present work, a series of activated carbon (AC) adsorbents were synthesized from the compost derived by the mechanical/biological treatment of municipal solid wastes and evaluated regarding their CO2uptake. The AC samples were characterized by sulfuric acid and calcination by N2at 400 and 800 °C. Then, the CO2uptake capacities were evaluated by dynamic breakthrough experiments in a temperature range of 40-100 °C and pressures up to 3 bar. The presented data were properly described by Langmuir model and it was revealed that the CMSW-S-800 sample, treated with sulfuric acid and activated at 800 °C, has the highest CO2uptake capacity with an amount adsorbed around 2.6 mol/kg at 40 °C. In the next step, a mathematical model has been developed to match the experimental dynamic breakthrough data and design a pressure swing adsorption (PSA) cyclic process to evaluate the capacity and potential of the best AC sample for CO2adsorption. The results arising from this work showed a possible route for the application of the compost as a source of activated carbon for the sorption of greenhouse gases.
- Single- A nd multicomponent fixed bed adsorption of CO2, CH4, and N2in binder-free beads of 4A zeolitePublication . Zafanelli, Lucas F.A.S.; Karimi, Mohsen; Henrique, Adriano; Rodrigues, Alírio; Silva, José A.C.Single- A nd multicomponent adsorption fixed bed breakthrough experiments of carbon dioxide (CO2), methane (CH4), and nitrogen (N2) on commercial binder-free beads of 4A zeolite have been studied at 313, 373, and 423 K and a total pressure of up to 5 bar. The ternary experiments (CO2/CH4/N2) show a practically complete separation of CO2 from CH4/N2 at all the temperatures studied, with selectivity at 313 K of CO2 around 24 over CH4 and 50 over N2. The adsorption equilibrium data measured from the breakthrough experiments were modeled by the dual-site Langmuir isotherm, and the breakthrough results were simulated with a fixed bed adsorption model taking into account axial dispersion, mass-transfer resistances, and heat effects. The mathematical model predicts with a good accuracy the systematic behavior of the single- A nd multicomponent breakthrough results based on the independent parameters calculated from well-established correlations and intracrystalline diffusivities for zeolite 4A available in the literature. The results showed in the present work evidence that the binder-free beads of zeolite 4A can be employed to efficiently separate CO2 from CO2/CH4/N2 mixtures by fixed bed adsorption.
- Capture of CO2 in activated carbon synthesized from municipal solid waste compostPublication . Karimi, Mohsen; Zafanelli, Lucas F.A.S.; Almeida, João P.; Silva, José A.C.; Rodrigues, Alírio; Ströher, Gylles R.In this study, municipal solid waste composts obtained from mechanical biological treat-ment has been considered as a source of adsorbents for CO2 capture. Three samples de-rived from the maturated compost in the municipal solid wastes were modified to produce activated carbon. The first sample was treated with sulfuric acid, the second one was thermally treated at 800 0C and the last one was modified chemically and thermally with sulfuric acid and at 800 0C. Then, the CO2 uptake capacity of prepared samples was measured through breakthrough adsorption experiments at the post combustion operation-al conditions to collect isotherm data. Also a fixed bed adsorption mathematical model was developed by applying mass and energy balances. Results showed the municipal solid wastes have an excellent capacity to be considered as source of adsorbent for CO2 capture also the mathematical model is able to predict breakthrough data.
- Post-combustion capture of CO2 in potassium-exchanged binder-free beads of Y zeolitePublication . Aly, Ezzeldin; Zafanelli, Lucas F.A.S.; Henrique, Adriano; Freitas, Francisco A. da Silva; Rodrigues, Alírio; Silva, José A.C.The generation of carbon dioxide is inherent in the combustion of fossil fuels, and the efficient capture of CO2 from industrial operations is regarded as an important strategy to achieve a significant reduction in atmospheric CO2 levels. Adsorption processes are promising capture technologies as they can use specific adsorbents by acting in the limit as molecular sieves to separate CO2 from other flue gas constituents. Experimental and theoretical studies concerning the adsorption of CO2 and N2 and their mixtures in potassium-exchanged Y zeolite (KY) are lacking information in the literature. Accordingly, this work aims to investigate by a series of fixed-bed adsorption breakthrough experiments the adsorption of single and binary mixtures (under compositions typical of post-combustion) of CO2/N2 in binder-free beads of KY zeolite, at 313, 373, and 423 K and total pressures up to 350 K. The single and multi-component breakthrough apparatus used in this work is shown in Figure 1. The dynamic equilibrium loading is calculated by integrating the molar flow profiles of the breakthrough curves, as explained in previous works [1]. The adsorption equilibrium data was then modelled by the extended dual-site Langmuir model, and the breakthrough curves were numerically simulated using ASPEN ADSORPTION. At 313 K and 350 kPa, the single-component data obtained showed that the amount adsorbed of CO2, and N2 is around 6.42 and 0.671 mol.kg-1, respectively. The binary experiments CO2/N2 carried out under typical post-combustion conditions, show a selectivity of CO2 over N2 around 104. Overall the numerical simulations performed on ASPEN ASDSORPTION provided results with decent accuracy and the model can predict the systematic behaviour of the breakthrough experiments as well as the dynamics of the fixed bed adsorption system. The results shown in the present work proves that potassium-exchanged binder-free beads of Y zeolite is a promising adsorbent that can efficiently separate CO2 from post-combustion streams by fixed bed adsorption.
- Vacuum pressure swing adsorption process using binder-free K(23)Y zeolite for post-combustion CO2 capturePublication . Aly, Ezzeldin; Zafanelli, Lucas F.A.S.; Henrique, Adriano; Gleichmann, Kristin; Rodrigues, Alírio; Freitas, Francisco A. da Silva; Silva, José A.C.This study presents the development of a Vacuum Pressure Swing Adsorption (VPSA) process utilizing binder- free K(23)Y zeolite for post-combustion CO2 capture. The ion-exchanged K(23)Y zeolite, characterized by a high CO2 selectivity of 97 over N2 at 10 kPa and an adsorption capacity exceeding 7 mol⋅kg− 1 350 kPa at 306 K, was evaluated under various operational conditions to optimize the VPSA process. Experimental and simulated breakthrough analyses provided essential data for adsorption equilibrium and sorption kinetics, which were modelled using Aspen Adsorption software. Optimization of key cycle steps, including pressurization, adsorption, blowdown, and evacuation, revealed that Light Product Pressurization significantly enhances process performance. Parametric studies demonstrated that reducing intermediate pressure from 0.2 bar to 0.07 bar increased CO2 purity from 84 % to 93 %, though it decreased recovery from around 99 % to 78 %, revealing a key trade-off. Similarly, extending adsorption time beyond 86 s enabled CO2 purity to exceed 90 %, though recovery decreased slightly. Under optimal conditions, the VPSA process achieved a CO2 purity and recovery of ~90 % and productivity of 0.367 molCO2⋅m− 3ads⋅s− 1 , with specific energy consumption of 144 kWh per ton of CO2 captured. The study demonstrates the viability of a simple 4-step VPSA configuration with binder-free K(23)Y, offering competitive performance and low energy consumption.
- 3D-printed activated carbon for post-combustion CO2 capturePublication . Zafanelli, Lucas F.A.S.; Henrique, Adriano; Steldinger, Hendryk; Díaz de Tuesta, Jose Luis; Gläsel, Jan; Rodrigues, Alírio; Gomes, Helder; Etzold, Bastian J.M.; Silva, José A.C.The applicability of 3D-printed activated carbons for their use to CO2 capture in post-combustion streams and the influence of activation conditions on CO2 uptake and CO2 to N2 selectivity were studied. For two monoliths with the same open cellular foam geometry but low and high burnoff during activation, a series of fixed-bed breakthrough adsorption experiments under typical post-combustion conditions, in a wide range of temperature (313 and 373 K), and partial pressure of CO2 up to 120 kPa were carried out. It is shown that the higher burnoff during activation of the 3D printed carbon enhances the adsorption capacity of CO2 and N2 due to the increased specific surface area with sorption uptakes that can reach 3.17 mol/kg at 313 K and 120 kPa. Nevertheless, the lower burnoff time on monolith 1 leads to higher selectivity of CO2 over N2, up to 18 against 10 on monolith 2, considering a binary interaction to a mixture of CO2/N2 (15/85 vol%) at 313 K. The single and multicomponent adsorption equilibrium is conveniently described through the dual-site Langmuir isotherm model, while the breakthrough curves simulated using a dynamic fixed-bed adsorption linear driving force model. Working capacities for the 3D printed carbon with lower burnoff time lead to the best results, varying of 0.15–1.1 mol/kg for the regeneration temperature 300–390 K. Finally, consecutive adsorption-desorption experiments show excellent stability and regenerability for both 3D printed activated carbon monoliths and the whole study underpins the high potential of these materials for CO2 capture in post-combustion streams.
- Single- and multi-component fixed-bed adsorption of CO2, CH4, and N2 on ion-exchanged binder-free NaY zeolitesPublication . Aly, Ezzeldin; Zafanelli, Lucas F.A.S.; Henrique, Adriano; Freitas, Francisco A. da Silva; Rodrigues, Alírio; Silva, José A.C.Ion-exchange was performed on bare commercial binder-free NaY zeolite with alkali (K+) and alkaline earth (Ca2+) metal cations in the range 23, 58, and 95% exchange for K+, and 56 and 71% for Ca2+, to be used as candidates regarding CO2 post-combustion capture (PCC) and biogas upgrading by adsorption processes. Adsorption equilibrium isotherms of CO2, CH4 and N2 were measured on all these cation-exchanged samples using a chromatographic technique between 308 and 348 K and pressures up to 350 kPa and modelled by the dual-site Langmuir isotherm. The CO2 adsorption capacity increases as Na+ is exchanged further by K+ and the reverse for the Ca2+ exchange. The single- and binary-component breakthrough curves were numerically simulated and accurately predicted using the Aspen Adsorption package. This work discloses the importance of ion-exchange on binder-free beads of NaY zeolite to improve its performance in PCC and biogas upgrading applications
- Separation of n/iso-paraffins in a hierarchically structured 3D-printed porous carbon monolithPublication . Henrique, Adriano; Zafanelli, Lucas F.A.S.; Aly, Ezzeldin; Steldinger, Hendryk; Gläsel, Jan; Rodrigues, Alírio; Etzold, Bastian J.M.; Silva, José A.C.Hierarchically structured 3D-printed porous carbons monoliths were investigated for their applicability in adsorptive n/iso-paraffin separation. Three materials of the same macroscopic shape were employed, which varied in the micro- and mesoporosity by altering the final CO2 activation step: non-activated and activated at 1133 K for 6 and 12 h, respectively. Chromatographic breakthrough experiments were conducted for pentane and hexane isomer mixtures at industrially relevant separation conditions. Results demonstrated that the initial porosity for the non-activated monolith enables the complete separation of linear paraffins from their branched isomers (slightly adsorbed) via a near molecular sieving effect. The Langmuir isotherm conveniently fitted the adsorption equilibrium data, and a dynamic mathematical model suitably predicted the breakthrough curves. Regarding the CO2 activated monoliths, both showed adsorption towards all alkanes with practically no selectivity between them.
- Separation of Branched Alkane Feeds with Metal-Organic FrameworksPublication . Henrique, Adriano; Brântuas, Pedro; Zafanelli, Lucas F.A.S.; Aly, Ezzeldin; Rodrigues, Alírio; Maurin, Guillaume; Serre, Christian; Silva, José A.C.The production of high-quality gasoline is currently achieved through the Total Isomerization Process that separates n/iso-paraffins in the pentane (C5) and hexane (C6) range while not reaching the ultimate goal of a research octane number (RON) higher than 92. This work demonstrates two promising alternatives/strategies using metal-organic frameworks (MOF) that lead to a novel adsorptive separation process to overcome this limitation. Here, the efficient discrimination of C5/C6 alkane isomers into valuable fractions of high RON (HRON – 2,3-dimethylbutane (23DMB; RON 105), 2,2-dimethylbutane (22DMB; RON 94), and isopentane (iC5; RON 93.5)) and low RON (LRON – n-pentane (nC5; RON 61.7), (nC6; RON 30), 2-methylpentane (2MP; RON 74.5), and 3-methylpentane (3MP; RON 75.5)) compounds is achieved.