Percorrer por autor "Ferreira, Alexandre"
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- Adsorption equilibrium and dynamics of fixed bed adsorption of CH4/N2in binderless beads of 5A zeolitePublication . Silva, José A.C.; Ferreira, Alexandre; Mendes, Patrícia A.P.; Cunha, Adelino F.; Gleichmann, Kristin; Rodrigues, AlírioThe sorption equilibrium of methane (CH4) and nitrogen (N2) in binderless beads of 5A zeolite is presented between 305 and 373 K and pressures up to 3 bar in a static electronic microbalance. The adsorbed amount of CH4 and N2 is around 1.6 and 1.02 mol/kgads, respectively, at 305 K and 3 bar. A comparison of these values with the ones in literature shows that the adsorption capacity of the 5A binderless beads is 20% higher than that of the 5A binder commercial materials. The CH4 and N2 adsorption isotherms were fitted with the simplest Langmuir model with a prediction of the maximum amount adsorbed for both compounds of 5.0 mol/kg. The heats of sorption are -16.6 and -15.1 kJ/mol for CH4 and N2, respectively. In the overall pressure and temperature range the isotherms of N2 seems practically linear. However, it was observed that the experimental data of N2 at low coverage (below 0.2 bar) deviates slightly from Type I isotherms. Thereafter, the binary sorption of CH4 and N2 has been investigated in a fixed bed adsorber at 313 and 343 K and total pressures up to 5 bar for 50(CH4)/50(N2) and 75(CH4)//25(N2) mixture ratios diluted in an inert helium stream. A mathematical model was formulated to compute the dynamic behavior of the fixed bed adsorber using the extended binary Langmuir model, showing close agreement with the measured binary breakthrough experiments in the partial pressure range of the components above 0.2 and below 3 bar. © 2015 American Chemical Society.
- Biogas upgrading using shaped MOF MIL-160(Al) by pressure swing adsorption process: Experimental and dynamic modelling assessmentPublication . Karimi, Mohsen; Siqueira, Rafael M.; Rodrigues, Alírio; Nouar, Farid; Silva, José A.C.; Serre, Christian; Ferreira, AlexandreBiogas has been introduced as a sustainable source of energy, which is considered as a promising alternative for conventional fossil fuels. Indeed, biogas requires to be upgraded from the impurities, specifically, carbon dioxide to be commercially utilized. In this study, the potential of shaped form MIL-160(Al) as a water stable Al dicarboxylate microporous MOF has been assessed concerning the biogas upgrading application. To this end, firstly, the dynamic fixed-bed adsorption of carbon dioxide and methane was investigated at 313 K and 4.0 bar. The measured breakthrough outcomes were simulated with a developed mathematical model, which the results confirmed an acceptable potential of model predictions. Afterwards, a pressure swing adsorption (PSA) process with 5-steps was designed relying on dynamic equilibrium results, and experimentally validated by a lab-scale PSA set-up for a 50:50 CO2/CH4 mixture. Finally, an industrial PSA process was designed to have a precise knowledge on the potential of MIL-160(Al) for biogas upgrading for large scale applications. The results demonstrated the purity and recovery of methane around 99 % and 63 %, respectively, which indicated the appealing capacity of this adsorbent for such a purpose.
- Developing pressure swing adsorption process for biogas upgrading using shaped MIL-160(Al)Publication . Karimi, Mohsen; Rodrigues, Alírio; Ferreira, Alexandre; Nouar, Farid; Cho, Kyung Ho; Lee, Hwang; Serre, Christian; Silva, José A.C.In this study, regarding the increasing interest on renewable sources of energy as well as considering the challenges of climate changes, the potential of shaped MOF MIL-160 (Al) for biogas upgrading has been evaluated. Accordingly, firstly the breakthrough assessments of CO2 and CH4 adsorption onto this sorbents were studied. Afterwards, a pressure swing adsorption (PSA) process to this end was designed and developed. The results showed MIL-160(Al) has an excellent potential for biogas upgrading concerning CO2 and CH4 separation.
- MIL-160(Al) as a candidate for biogas upgrading and CO2 capture by adsorption processesPublication . Karimi, Mohsen; Ferreira, Alexandre; Rodrigues, Alírio; Nouar, Farid; Serre, Christian; Silva, José A.C.The microporous bioderived Al dicarboxylate MIL-160(Al) MOF in its shaped form has been evaluated as a candidate for biogas upgrading (BU) and/or carbon capture and storage (CCS) by studying adsorption isotherms of CO2, CH4, and N2 at 313, 343, and 373 K until 8 bar. The isotherms disclosed the following loading capacities: 4.2 (CO2), 2.07 (CH4), and 0.69 (N2) mol/kg at 5.8 bar and 313 K, which fitted with the dual-site Langmuir model. The linear-driving-force coefficients (LDFs) for CO2 and CH4 calculated from uptake rate experiments are in the order of 0.021-0.096 and 0.041-0.165 s-1 at 313 K between 0.11 and 2.76 bar, respectively. The Response Surface Methodology (RSM) was also applied to maximize the selectivity for mixtures CO2/CH4 and CO2/N2 with interest for BU or CCS. Breakthrough curve experiments with mixtures CO2/CH4 and CO2/N2 at the optimum selectivity conditions were developed and simulated using ASPEN Adsorption. This work clearly demonstrates the potential of MIL-160(Al) to be used in BU and/or CCS-related applications.
- Multicomponent chiral separations by multicolumn and simulated moving bed adsorption processesPublication . Ribeiro, António E.; Graça, Nuno S.; Ferreira, Alexandre; Rodrigues, Alírio; Pais, Luís S.This work will present a complete methodology concerning experimental, modelling and simulation results. Both the CHIRALPAK AD and CHIRALPAK IA CSP will be evaluated. The selection of the proper CSP/solvent combination for preparative operation will be fully study taking into account the screening strategy proposed by Zhang et al. Additional results include the measurement of nadolol stereoisomers solubilities, equilibrium adsorption data and fixed bed (breakthroughs) experiments. The complete screening of CSP/solvent combination will lead to the choice of the better solutions for the separation of nadolol stereoisomers, considering the target component or components to be obtained. Simulation and experimental results will be presented for the multicomponent separation of nadolol stereoisomers by multicolumn and Simulated Moving Bed adsorption processes.
- Separation of CO2/N2 mixture by pressure swing adsorption process using shaped MI-160(Al) for CO2 post-combustion capturePublication . Karimi, Mohsen; Rodrigues, Alírio; Ferreira, Alexandre; Nouar, Farid; Cho, Kyung Ho; Lee, Hwang; Serre, Christian; Silva, José A.C.Breakthrough experiments were properly simulated with ASPEN ADSIM. Cyclic steady state were developed after 10 cycles. Shaped MOF MIL-160(Al) showed and excellent capacity for Post-combustion CO2 Capture. Life cycle assessment (LCA) of MIL-160 for Postcombustion CO2 Capture can be considered as a future direction.
- Separation performance of shaped MOF MIL-160(AL) for double applications of pre and post combustion carbon capturePublication . Karimi, Mohsen; Ferreira, Alexandre; Rodrigues, Alírio; Nouar, Farid; Cho, Kyung Ho; Lee, Hwang; Serre, Christian; Silva, José A.C.The world currently faces the dual challenges: climate changes caused by global warming and a high energy demand regarding the exponential population expansion and industrial development [1, 2]. Carbon dioxide, methane, nitrogen oxide and halogenated components are the main anthropogenic greenhouse gases (GHGs) [1]. The challenge of reducing GHGs emission can be overcome by successful developing post-combustion CO2 capture also advancing the green and renewable sources of energy including biogas [3]. Nevertheless, the main drawback concerning the biogas is its high content on carbon dioxide (it might be as high as 40% or more), which significantly reduces its heating capacity. Therefore, for biogas applications, a previous separation step is required to reduce the CO2 content [2,3]. Among the different methodologies for biogas upgrading and postcombustion CO2 capture, adsorption is among the most attractive ones
- Solar-driven thermo-photocatalytic CO2 methanation over a structured RuO2:TiO2/SBA-15 nanocomposite at low temperaturePublication . Paulista, Larissa Oliveira; Ferreira, Alexandre; Castanheira, Bruna; Ðolić, Maja B.; Martins, Ramiro; Boaventura, Rui; Vilar, Vítor J.P.; Silva, Tânia F.C.V.A new hybrid catalyst composed of mesostructured silica SBA-15 functionalized with TiO2 and further loaded with RuO2 was developed to efficiently promote thermo-photocatalytic CO2 hydrogenation into methane at low temperatures. The catalytic activity was assessed with respect to TiO2:RuO2 loading, catalyst dosage, illumination source (polychromatic sunlight and monochromatic LEDs) and power, [H2]:[CO2] molar ratio, temperature, and catalyst reusability. The best methanation yields were attained for the RuO2(6.4%):TiO2(16.9%)/SBA-15 nanocomposite at 150 ºC, under simulated sunlight (0.21 W) and stoichiometric [H2]:[CO2] molar ratio, reaching: a specific CH4 production rate of 13.6 mmol g-c1a t h-1; 99.8 % selectivity; 96.8 % CO2 conversion (110- min; 40 mL); and apparent photonic efficiency/quantum yield of 39.5 %/42.1 %. Considering only the active RuO2:TiO2 photocatalyst mass (23.3 %), the CH4 production rate increased to 58.6 mmol g-a1c tive_cat h-1. Besides, this highly-active photocatalyst featured excellent UV-Vis-IR light absorbance, high surface area, and stability for reuse when moist gas was removed between cycles.
- Zeolite Beta Membranes for the Octane Upgrading of C5/C6 Light NaphtaPublication . Silva, José A.C.; Rodrigues, Alírio; Bárcia, Patrick da Silva; Ferreira, Alexandre; Gascon, Jorge; Aguado, Sónia; Kapteijn, FreekThe zeolite Beta membranes were prepared by secondary growth method in asymmetric tubular Al2O3 supports (Inocermic GmbH, Germany), combining three different types of seeding techniques and crystallization conditions. Figure 1 show SEM micrographs of a typical non-calcined beta membrane synthesized in this work (cross section view). The vapour permeation experiments performed in the apparatus shown in Figure 2 with mixtures of nHEX, 3MP, 23DMB and 22DMB show that permeate flux increase as the degree of branching decreases following the order: nHEX>>3MP>23DMB>22DMB. Approximately one third of the feed stream cross the membranes. Figure 3 shows that in the retentate stream the fractions of monobranched and normal hexane isomers (low RON compounds) decrease while the concentration of dibranched isomers (high RON compounds) is increased in relation to the equimolar feed composition. Consequently, the RON can be boosted in retentate up to 3.8 points. These results demonstrate the potential of the zeolite beta membranes for application in the production of additive-free premium gasoline.
- Zeolite Beta membranes for the separation of hexane isomersPublication . Bárcia, Patrick da Silva; Silva, José A.C.; Gascon, Jorge; Aguado, Sónia; Ferreira, Alexandre; Rodrigues, Alírio; Kapteijn, FreekThe preparation of a-alumina supported zeolite Beta membranes was successfully achieved and sped up by exploring combinations of three seeding techniques and three synthetic methods. The surface of the membranes was completely covered by well intergrown crystals; the thickness of the zeolite layers ranged from 2 to 6 lm depending on the synthesis method used. The quality of the membranes was tested by means of pervaporation of ethanol/1,3,5-triisopropylbenzene (TIPB) mixtures together with permporometry experiments. The performance in the vapour separation of quaternary equimolar mixtures of nhexane (nHEX), 3-methylpentane (3MP), 2,3-dimethylbutane (23DMB) and 2,2-dimethylbutane (22DMB) in the range 343–443 K showed that permeate flux decreases as the branching degree increases following the order: nHEX 3MP > 23DMB > 22DMB. In the retentate, the fractions of monobranched and normal hexane decrease while the concentration of dibranched isomers is increased compared to the feed composition. The influence of the temperature in the permeation fluxes indicates the existence of an activated transport mechanism which favours the permeation of more nHEX and 3MP with regard to their dibranched isomers. The octane number (ON) of the quaternary mixture was enhanced up to 5 points with the best synthesized membrane.