Kinetics of water adsorption in microporous aluminophosphate layers for regenerative heat exchangers

Heyden, Hendrik van; Munz, Gunther; Schnabel, Lena; Schmidt, Ferdinand; Mintova, Svetlana; Bein, Thomas

doi:10.1016/j.applthermaleng.2008.07.001

Cited by 66 publications

(32 citation statements)

References 36 publications

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“…A number of studies were carried out on different types of (silico)aluminophosphates (AlPO5, AlPO18, SAPO34, etc.) [39][40][41], confirming the interesting properties of such materials for adsorption cycles. Originally synthesized for catalytic interest, only few SAPO zeolites have been utilized in industrial processes for their moderate Bronsted acidity, like in lube oil dewaxing by Chevron and in methanol-to-olefins conversion by UOP.…”

Section: Zeolitessupporting

confidence: 61%

Basics of Adsorption Heat Pump Processes

Freni

Dawoud

Bonaccorsi

et al. 2015

SpringerBriefs in Applied Sciences and Technology

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Section: Zeolitessupporting

confidence: 61%

Basics of Adsorption Heat Pump Processes

Freni

Dawoud

Bonaccorsi

et al. 2015

SpringerBriefs in Applied Sciences and Technology

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“…More recently, SAPO zeotypes have been successfully proposed as possible alternative to alluminosilicate zeolites [4,5]. SAPO-34, for example, shows a water adsorption equilibrium curve with a typical ''S-shaped'' trend particularly suitable in the range of temperatures and pressures used in the thermodynamic cycle of adsorption heat pumps driven by low temperature sources [6].…”

Section: Introductionmentioning

confidence: 99%

Hydrothermal and microwave synthesis of SAPO (CHA) zeolites on aluminium foams for heat pumping applications

Bonaccorsi

Calabrese

Freni

et al. 2013

Microporous and Mesoporous Materials

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“…13 For AlPOs, where such strong interaction sites are absent, it can be expected that the heat of adsorption changes only moderately as a function of the water loading. In addition to the investigation of powder samples, composites of AlPOs or SAPOs and support materials, primarily aluminium sheets or foams, 5,[17][18][19][20] have been successfully prepared and characterised. The development of stable composites is pivotal for the actual application of these materials in adsorptive heat transformations.…”

Section: Introductionmentioning

confidence: 99%

Interaction of water with (silico)aluminophosphate zeotypes: a comparative investigation using dispersion-corrected DFT

Fischer

2016

Phys. Chem. Chem. Phys.

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Porous aluminophosphates (AlPOs) and silicoaluminophosphates (SAPOs) with zeolite-like structures have received considerable attention as potential adsorbents for heat transformation applications using water adsorption/desorption cycles. Since a detailed experimental characterisation of the water adsorption properties has only been performed for some of these materials, such as AlPO-18 (AEI topology) and SAPO-34 (CHA topology), more systematic insights regarding the influence of the pore topology and (for SAPOs) the arrangement of the framework protons on the affinity towards water are lacking. To study the relationships between structure and properties in more detail, the interaction of water with six structurally different AlPOs (with AEI, AFX, CHA, ERI, GIS, RHO topologies) and their SAPO analogues was investigated using dispersion-corrected density-functional theory (DFT-D) calculations. Different possible locations of silicon atoms and charge-balancing protons were considered for the SAPO systems. The calculations for SAPOs at low water loadings (one H2O molecule per framework proton) revealed that the interaction energies exhibit a considerable variation, ranging from -75 to -100 kJ mol(-1) (per water molecule). The differences in interaction energy were rationalised with the different structural environment of the framework protons at which the water molecules are adsorbed. At high water uptakes (near saturation), interaction energies in the range of -65 kJ mol(-1) were obtained for all AlPOs, and there was no evidence for a marked influence of pore size and/or topology on the interaction strength. The interaction of water with SAPOs was found to be approximately 5 kJ mol(-1) stronger than for AlPOs due to an increased contribution of electrostatic interactions. An analysis of the structural changes upon water adsorption revealed striking differences between the distinct topologies, with the materials with GIS and RHO topologies being distorted much more drastically than the systems based on double six-ring (d6r) units. Moreover, the direct coordination of water molecules to framework aluminium atoms occurs more frequently in these materials, an observation that points towards a reduced structural stability upon hydration.

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Kinetics of water adsorption in microporous aluminophosphate layers for regenerative heat exchangers

Cited by 66 publications

References 36 publications

Basics of Adsorption Heat Pump Processes

Basics of Adsorption Heat Pump Processes

Hydrothermal and microwave synthesis of SAPO (CHA) zeolites on aluminium foams for heat pumping applications

Interaction of water with (silico)aluminophosphate zeotypes: a comparative investigation using dispersion-corrected DFT

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