Filipe V. S. Lopes

Adsorption of H2, CO2, CH4, CO, N2 and H2O in Activated Carbon and Zeolite for Hydrogen Production

Abstract The design of a layered pressure swing adsorption unit to treat a specified off-gas stream is based on the properties of the adsorbent materials. In this work we provide adsorption equilibrium and kinetics of the pure gases in a SMR off-gas: H2O, CO2, CH4, CO, N2, and H2 on two different adsorbents: activated carbon and zeolite. Data were measured gravimetrically at 303–343 K and 0–7 bar. Water adsorption was only measured in the activated carbon at 303 K and kinetics was evaluated by measuring a breakthrough curve with high relative humidity.

Adsorption of Off‐Gases from Steam Methane Reforming (H2, CO2, CH4, CO and N2) on Activated Carbon

Abstract Hydrogen is the energy carrier of the future and could be employed in stationary sources for energy production. Commercial sources of hydrogen are actually operating employing the steam reforming of hydrocarbons, normally methane. Separation of hydrogen from other gases is performed by Pressure Swing Adsorption (PSA) units where recovery of high‐purity hydrogen does not exceed 80%. In this work we report adsorption equilibrium and kinetics of five pure gases present in off‐gases from steam reforming of methane for hydrogen production (H2, CO2, CH4, CO and N2). Adsorption equilibrium data were collected in activated carbon at 303, 323, and 343 K between 0‐22 bar and was fitted to a Virial isotherm model. Carbon dioxide is the most adsorbed gas followed by methane, carbon monoxide, nitrogen, and hydrogen. This adsorbent is suitable for selective removal of CO2 and CH4. Diffusion of all the gases studied was controlled by micropore resistances. Binary (H2‐CO2) and ternary (H2‐CO2‐CH4) breakthrough curves are also reported to describe the behavior of the mixtures in a fixed‐bed column. With the data reported it is possible to completely design a PSA unit for hydrogen purification from steam reforming natural gas in a wide range of pressures.

Bacteria and fungi inactivation by photocatalysis under UVA irradiation: liquid and gas phase.

AbstractIn the last decade, environmental risks associated with wastewater treatment plants (WWTPs) have become a concern in the scientific community due to the absence of specific legislation governing the occupational exposure limits (OEL) for microorganisms present in indoor air. Thus, it is necessary to develop techniques to effectively inactivate microorganisms present in the air of WWTPs facilities. In the present work, ultraviolet light A radiation was used as inactivation tool. The microbial population was not visibly reduced in the bioaerosol by ultraviolet light A (UVA) photolysis. The UVA photocatalytic process for the inactivation of microorganisms (bacteria and fungi, ATCC strains and isolates from indoor air samples of a WWTP) using titanium dioxide (TiO2 P25) and zinc oxide (ZnO) was tested in both liquid-phase and airborne conditions. In the slurry conditions at liquid phase, P25 showed a better performance in inactivation. For this reason, gas-phase assays were performed in a tubular photoreactor packed with cellulose acetate monolithic structures coated with P25. The survival rate of microorganisms under study decreased with the catalyst load and the UVA exposure time. Inactivation of fungi was slower than resistant bacteria, followed by Gram-positive bacteria and Gram-negative bacteria. Graphical abstractInactivation of fungi and bacteria in gas phase by photocatalitic process performed in a tubular photoreactor packed with cellulose acetate monolith structures coated with TiO2

Zeolite Apgiia for Adsorption Based Carbon Dioxide Capture

Adsorption of synthetic flue gas on a commercial zeolite 13X (APGIIA) with targeted Si/Al ratio has been studied aiming to design an adsorption process for CO2 capture from post-combustion power plants. Adsorption equilibrium of pure gases (CO2 and N2) has been measured in a wide range of temperatures: 303, 333, 363, 393, 423, 473 K. Adsorption equilibrium was fitted with the multisite Langmuir model. The adsorption capacity of the zeolite pellets for CO2 is 4.54 mol/kg and 0.26 mol/kg for N2 at 303 K and 100 kPa. The dynamic behavior of the pellets in a fixed bed was also studied by measuring breakthrough curves. Adsorption and desorption was analyzed in order to understand the regeneration of the adsorbent. Based on equilibrium and kinetic data, two different adsorption technologies were simulated: Vacuum Pressure Swing Adsorption (VPSA) and Temperature Swing Adsorption (TSA). A CO2 recovery of 63.0% with 72.1% purity was obtained using a five-step PSA cycle included rinse step. In a 5-step TSA process, however, a CO2 purity of 78.7% and recovery of 76.6% can be achieved under a heating temperature of 423 K.

Attractive demonstrations with wire programming robot “REDi”

Robots created for education have different purposes, from learning algorithms to learning robotics. It has been shown that robots can increase the students interest. Our proposed robot, REDi, uses wire programming to introduce students to the basics of robotics and algorithms. With this robot, attractive, interactive demonstrations can be achieved even with students that have no background in the area.