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- Analyses of adsorption behavior of CO2, CH4, and N2 on different types of BETA ZeolitesPublication . Henrique, Adriano; Karimi, Mohsen; Silva, José A.C.; Rodrigues, AlírioThe adsorption equilibrium and kinetics of CO2, CH4, and N2 on three types of BETA zeolites were investigated at different temperatures and a defined partial pressure range from dynamic breakthrough experiments. The adsorbed amount followed the decreasing order of CO2 >CH4 >N2 for all studied materials. For the same ratio of SiO2/Al2O3, the Na-BETA-25 zeolite showed a higher uptake capacity than H-BETA-25, due to the presence of a Na+ cationic center. Comparing the same H+ compensation cation, zeolite H-BETA-25 expressed a slightly higher adsorption capacity than H-BETA-150. Regarding the selectivity of gases, based on their affinity constants, H-BETA-150 displayed the best ability. The adsorption kinetics was considered using the zero-length-column (ZLC) technique. Response surface methodology (RSM) was applied to evaluate the interactions between adsorption parameters and to describe the process.
- 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.; Golini Pires, MarcellaThe 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.
- 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.
- Thermally and chemically activated biochar obtained in mechanical biological treatment plants for carbon dioxide adsorptionPublication . Karimi, Mohsen; Brântuas, Pedro; Henrique, Adriano; Gonçalves, Carmem Natália de Pina; Silva, José A.C.; Rodrigues, AlírioIn this study, based on the scopes of CCS strategy and municipal solid waste management, a novel Integrated Environment Management (IEM) strategy has been proposed. In this way, the obtained compost in the mechanical biological treatment from municipal solid wastes has been considered as a source of adsorbents for CO2 capture. In this way, the maturated compost waste was modified by liquid phase treatment with sulfuric acid and thermal treatment at 800 ºC. Then, the prevalent operational conditions of post-combustion processes have been considered to find the best prepared samples for CO2 capture.
- Separation of hexane isomers in metal organic framework ZIF-8Publication . Karimi, Mohsen; Henrique, Adriano; Brântuas, Pedro; Silva, José A.C.; Rodrigues, AlírioThe performance of porous metal organic framework ZIF-8 in the separation of all five hexane isomers (nHEX, 2MP, 3MP, 23DMB, 22DMB), is evaluated through a series of multicomponent breakthrough adsorption experiments, at the temperatures of 373, 423 and 473 K and up to partial pressures of 0.5 bars. The reported data shows for all experiments the following sorption hierarchy: nHEX >> 2MP > 3MP >> 23DMB > 22DMB. It is also demonstrated that the sorption of nHEX is equilibrium based in contrast with the sorption of branched isomers which is kinetic controlled. The experimental data is also simulated through a mathematical model developed in MATLAB code, being the results in qualitatively agreement. This paper shows that it possible to separate the hexane isomers in ZIF-8 by classes linear/mono-branched/di-branched if proper experimental conditions are set-up, being the result of importance for the octane upgrading of gasoline.
- Equilibrium adsorption of CO2, CH4 and N2 on BETA zeolites at post-combustion operational conditionsPublication . Karimi, Mohsen; Brântuas, Pedro; Henrique, Adriano; Silva, José A.C.; Rodrigues, AlírioThe adsorption equilibrium and kinetics of CO2,CH4, and N2 on three types of BETA zeolites were investigated at different temperatures and a defined partial pressure range from dynamic breakthrough experiments. The adsorbed amount followed the decreasing order of CO2>CH4>N2 for all studied materials. For the same ratio of SiO2/Al2O3, the Na-BETA-25 zeolite showed a higher uptake capacity than H-BETA-25, due to the presence of a Na+cationic center. Comparing the same H+compensation cation, zeolite H-BETA-25 expressed a slightly higher adsorption capacity than H-BETA-150. Regarding the selectivity of gases, based on their affinity constants, H-BETA-150 displayed the best ability. The adsorption kinetics was considered using the zero-length-column (ZLC) technique.
- Separation of hexane isomers using ZIF-8Publication . Henrique, Adriano; Silva, José A.C.; Rodrigues, AlírioAn important process in petrochemical industry is the octane upgrading of gasoline by the separation of paraffin isomers in the range C5/C6. The gasoline obtained from crude oil has a high fraction of linear and monobranched alkanes, which must be converted into isomers with high degree of ramification to improve the research octane number (RON) (Ferreira et al. 2013). The RON is one of the parameters of gasoline quality and as higher its value, better is the combustion, reducing the tendency of a rapid and inefficient detonation of the hydrocarbons. In other words, the combustion occurs like a smooth explosion, improving the performance of the motor (Mendes et al. 2014). The separation of n/iso-paraffins is actually realized by the Total Isomerization Process (TIP), which consist in performing the isomerization of normal paraffins, with low levels of RON to mono or di-branched isomers, and then, the paraffins with a high octane degree are separated from the others (Peralta et al. 2012). The research octane number increase as the branching degree of the paraffin increases. In this way, the objective of this work is to study the separation of hexane isomers using a Metal Organic Framework (MOF) i.e. ZIF-8 (Zeolitic Imidazolate Framework) to improve the octane rating of gasoline in TIP processes. The MOF ZIF-8 shows chemical and thermal robustness and its structure consist of a cubic arrangement with 8 sodalite cages in the corner (Park et al. 2006). In this work, several studies of the adsorption of hexane isomers on ZIF-8 were performed, with an equimolar mixture of: n-hexane (n-HEX), 2,2-dymethilbutane (22DMB), 2,3- dymethilbutane (23DMB), 3-methylpentane (3MP) and 2-methypentane. During those experiments the temperatures and hydrocarbon pressure covers temperatures 373, 423 and 473 K and pressure range 2-10 kPa. Figure 1 shows a typical breakthrough curves for the C6 isomers at hydrocarbon pressure 5 kPa and temperature at 373 K. Figure 1 show that ZIF-8 is capable to perform the kinetic separation of hexane isomers in different classes, where the sorption hierarchy is: nHEX>>>2MP>3MP>>23DMB>22DMB. It is also being developed a numerical package using the Method of Lines (MOL) (Schiesser and Griffiths 2009) in MATLAB code to simulate the breakthrough-curves experiments. From this work, it can be concluded that ZIF-8 can be an efficient separator of hexane isomers in classes: linear>monobrached>dibranched paraffins, with a high impact in the upgrading of actual TIP processes in petrochemical industry.
- 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.
- Purificação do biogás em sólidos porososPublication . Henrique, Adriano; Lenzi, Giane G.; Silva, José A.C.biogás é uma mistura gasosa obtida pela decomposição anaeróbia da matéria orgânica, é constituído essencialmente por metano e dióxido de carbono e pequenas quantidades de outros compostos. Devido à sua alta quantidade de metano, o biogás pode ser utilizado como combustível, porém, necessita passar por um processo de purificação, com o objetivo de remover o CO2 dessa mistura e transformá-la em biometano. Nesse aspeto, o presente trabalho foi dedicado a estudar a purificação do biogás, utilizando o processo de adsorção, em que foram realizados estudos do equilíbrio de adsorção em três tipos de zeólitos da família BEA (H-BEA-25, H-BEA-150 e Na-BEA-25) por cromatografia gasosa, em leito fixo, para os componentes puros CO2, CH4 e N2 afim de obter as suas isotérmicas de adsorção. Também foram realizados estudos de transferência de massa, de modo a determinar o mecanismo de controle de difusão predominante no adsorvente utilizado. As isotérmicas de adsorção foram medidas nas temperaturas de 313, 373 e 423 K, e com pressões parciais na faixa de 0,33 a 4,16 bar. A quantidade de material adsorvida nos zeólitos BEA para os componentes estudados, decresce na seguinte ordem CO2 > CH4 > N2. Os estudos de transferência de massa foram realizados pela técnica ZLC (zero lenght column) utilizando como adsorbato o CO2 a uma pressão parcial de 0,03 bar, com o sistema a pressão total de 1 bar e temperatura de 313 K. Os resultados obtidos indicam que não existem resistências à transferência de massa, nas condições experimentais estudadas.