Universal Relation Between the Boundary Temperatures of a Basic Cycle of Sorption Heat Machines
Science article
Общее 
Language:
Английский,
Genre:
Full article,
Status:
Published,
Source type:
Original

Journal 
Chemical Engineering Science
ISSN: 00092509
, EISSN: 18734405

Output data 
Year: 2008,
Volume: 63,
Number: 11,
Pages: 29072912
Pages count
: 6
DOI:
10.1016/j.ces.2008.03.011

Tags 
Adsorption heat machines, Ammoniacarbon, Ammoniawater, Methanolcarbon, Trouton's rule, Waterlithium bromide, Watersilica gel, WaterSWS, Waterzeolite 
Authors 
Aristov Yu.I.
^{1}
,
Tokarev M.M.
^{1}
,
Sharonov V.E.
^{1}

Affiliations 
1 
Boreskov Institute of Catalysis SB RAS


For analyzing a basic cycle of an adsorption heat machine (AHM) an empiric rule was suggested, which manifests that adsorption isosters and equilibrium line View the MathML source for the pure sorbate intersect at T approaching infinity. This rule prompts how to plot the cycle, gives a link between the boundary temperatures of the cycle and allows estimation of a minimal temperature View the MathML source of an external heat source that is necessary to drive the cycle. In this paper the validity of the View the MathML source estimation was justified for working pairs which are most commonly used for adsorption units: water–silica gel, water–zeolite 13X, water–zeolite 4A, water–selective water sorbents (SWSs), CO2–carbon, methanol–carbons (AC35, TA90), methanol–hydrophobic zeolite CBV 901 Y and ammonia–carbon PX31. Four main working pairs for absorption heat machines—ammonia–water, water–LiBr, methanol–LiBr and R22–isobutylacetate—are also analyzed. This allowed the formulation of requirements to an optimal adsorbent to be used in a singleeffect nonregenerative cycle of an AHM. The accuracy of the View the MathML source estimation was examined for each pair. Moreover, it was shown that Trouton's rule is always valid if sorption equilibrium obeys the Polanyi potential theory, i.e., the equilibrium sorption is a unique function of the sorption potential ΔF=RTln(P/P0). For chemical reactions between various salts and sorbates this rule is violated because of a large difference between the standard changes of the entropy and enthalpy in the course of reaction and evaporation. In this case View the MathML source can be calculated from the Clausius–Clapeyron and VantHoff equations.