28 research outputs found
Disputatio Iuridica De Consuetudine
No full textQuam Concedente Magnifico ICtorum Witteb. Ordine Praeside ... Dn. Wernero Theodoro Martini ... Publice Examinandam proponet Johann Christoph Gleichmann Dresdens. Misnic. In Auditorio ICtorum Die XXII. MartiiNicht identisch mit VD17 1:002431Q (unterschiedl. Schlüssels., vgl dort: "... proponet Author Responsurus Johann Christoph Gleichmann ..."
Green hydrogen recovery from natural gas grids by adsorption process
No full textIn this work, the binder-free zeolite 13X was tested to purify green
hydrogen injected into natural gas grids. Green hydrogen can be a key
factor in meeting global energy demand while contributing to climate
goals. In this way, breakthrough curve experiments were performed to
assess the equilibrium and kinetic adsorption for H2 and CH4 in binder-
free zeolite 13X. This work covers the lack of adsorption data and
multicomponent breakthrough curves of H2/CH4 at low temperatures
(until 195 K) which were not available in the literature. The
equilibrium data were modeled by using the dual-site Langmuir
isotherm model and the multicomponent breakthrough curves were
simulated using a mathematical model implemented in MATLAB.
Performance parameters based on equilibrium data were discussed.
Overall, binder-free zeolite 13X has great potential to separate H2 from
CH4 based on equilibrium (higher capacity for CH4 with fast diffusion
of both gases).The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) under project PTDC 2020 * 3599-PPCDTI *
Engenharia dos Processos Químicos * project PTDC/EQU- EPQ/0467/2020. Also, through national funds FCT/MCTES (PIDDAC)
to CIMO (UIDB/00690/2020 and UIDP/00690/2020), SusTEC (LA/P/0007/2021), ALiCE (LA/P/0045/2020), and LSRE-LCM
(UIDB/50020/2020 and UIDP/50020/2020). Additionally, we thank national funding by FCT through the individual Ph.D. research
grant SFRH/BD/7925/2020 of Lucas F. A. S. Zafanelli. Moreover, the authors are grateful to Kristin Gleichmann and Chemiewerk
Bad Koestritz GmbH for kindly providing the binder-free beads of zeolite 13X studied in this work.info:eu-repo/semantics/publishedVersio
Dynamics of droplet formation at T-shaped nozzles with elastic feed lines
No full textWe describe the formation of water in oil droplets, which are commonly used in lab-on-a-chip systems for sample generation and dosing, at microfluidic Tshaped nozzles from elastic feed lines. A narrow nozzle forms a barrier for a liquid–liquid interface, such that pressure can build up behind the nozzle up to a critical pressure. Above this critical pressure, the liquid bursts into the main channel. Build-up of pressure is possible when the fluid before the nozzle is compressible or when the channel that leads to the nozzle is elastic. We explore the value of the critical pressure and the time required to achieve it. We describe the fluid flow of the sudden burst, globally in terms of flow rate into the channel and spatially resolved in terms of flow fields measured using micro-PIV. A total of three different stages—the lag phase, a spill out phase, and a linear growth phase—can be clearly discriminated during droplet formation. The lag time linearly scales with the curvature of the interface inside the nozzle and is inversly proportional to the flow rate of the dispersed phase. A complete overview of the evolution of the growth of droplets and the internal flow structure is provided in the digital supplementChemical EngineeringApplied Science
Purification of green hydrogen from natural gas grids using zeolite 13X
No full textGreen hydrogen (GH) is a hot topic in the shift to clean energy, holding a promise
to meet global energy demand while contributing to climate action goals. Its transportation can
be done into Natural Gas (NG) grids, being necessary a separation technology to provide pure
GH and NG to the end user. Accordingly, in this work, a series of breakthrough experiments
evaluated the performance of binder-free zeolite 13X as a potential adsorbent to purify GH
blended into NG grids. Single and multicomponent experiments were performed at 195, 231, and
273 K and pressure up to 1800 kPa. Noteworthy, the material enables a thermodynamic-based
separation of these components due to its strong interaction with CH4, resulting in selectivity
values up to 17 at 195 K. The dual-site and standard Langmuir isotherm models fitted the adsorption equilibrium data, being the simulated multicomponent breakthrough curves suitably predicted by a homemade dynamic mathematical model.The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) under
project PTDC 2020 * 3599-PPCDTI * Engenharia dos Processos Químicos * project PTDC/EQU-EPQ/0467/2020. Also, through national funds FCT/MCTES (PIDDAC) to CIMO (UIDB/00690/2020 and UIDB/00690/2020), SusTEC (LA/P/0007/ 2021), ALiCE (LA/P/0045/2020), and LSRE-LCM (UIDB/50020/2020 and UIDP/50020/2020). Additionally,
we thank national funding by FCT through the individual PhD research grant
SFRH/BD/7925/2020 of Lucas F. A. S. Zafanelli. Moreover, the authors are grateful to Kristin
Gleichmann and Chemiewerk Bad Koestritz GmbH for kindly providing the binder-free beads of
zeolite 13X studied in this work.info:eu-repo/semantics/publishedVersio
Designing a simple volumetric apparatus for measuring gas adsorption equilibria and kinetics of sorption. Application and validation for CO
No full textThe screening of adsorbents (zeolites, MOFs, ACs, etc) requires the measurement of adsorption equilibria and kinetics at the milligram scale. In this regard, a volumetric apparatus (constant volume variable pressure – batch adsorber) has been developed for studying adsorption equilibria and kinetics of sorption. Its validation was accomplished by studying the adsorption equilibria of carbon dioxide (CO2), methane (CH4) and nitrogen (N2) and the kinetics of sorption of CO2 on commercial binder-free 4A zeolite. The data collected has an acceptable agreement with already published values by a gravimetric and breakthrough flow technique. The isotherms were modeled using Sips model from low pressure till 8 bar at 303, 343 and 373 K. The sorption kinetics of CO2 was measured from the uptake rate experiments and fitted with a solid-film linear-driving-force model (LDF). It was observed that the LDF mass transfer coefficients increase with pressure and temperature. Finally, the statistical analysis of the data was performed by Response Surface Methodology (RSM) to determine the interactions among process variables such as temperature and pressure in the respective gas adsorption equilibria data.Authors would like to acknowledge Kristin Gleichmann and Chemiewerk
Bad Koestritz GmbH for kindly providing the binder-free beads of
4A zeolite. This work was financially supported by: 1) Project
′′VALORCOMP′′ (ref.0119_VALORCOMP_2_P), financed through
INTERREG V A Spain Portugal (POCTEP) 2014-2020, under the European
Regional Development Fund (ERDF). 2) Project POCI-01-0145-
FEDER006984-Associate Laboratory LSRE-LCM funded by ERDF
through COMPETE2020, Programa Operacional Competitividade e
Internacionalizaç˜ao (POCI), and by national funds through Foundation
for Science and Technology (FCT, Portugal) and ERDF under Programme
PT2020 to CIMO (UID/AGR/00690/2019); 4) M. Karimi also
recognizes a PhD research grant awarded by FCT –under SFRH/BD/
140550/2018.info:eu-repo/semantics/publishedVersio
Performance of an open thermal adsorption storage system with Linde type A zeolites: Beads versus honeycombs
No full textS.179-184The process of the discharging performance of an open thermal adsorption storage was investigated by tests in a 1.5-L-lab-storage accompanied by computational fluid dynamics (CFD) simulations. The storage materials were Linde-type 4A-zeolite beads and honeycomb structures both with and without binder. Additional information about the water adsorption properties und secondary pore structure was obtained by thermogravimetry, isotherm measurements and mercury intrusion. In accordance to the experimental observations and different to the CFD-results the binderless zeolite honeycombs showed the best adsorption dynamics but not the binder containing honeycombs. The accelerated adsorption kinetics in the walls of the binderless honeycombs may be caused by the optimal secondary pore size distribution and leads to an improved adsorption/discharge performance.20
