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Binary and ternary adsorption equilibria for CO2/CH4/N2 mixtures on Zeolite 13X beads from 273 to 333 K and pressures to 900 kPa

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Reliable adsorption equilibrium data and theoretical models for their accurate representation are crucial to the design of any adsorption based separation. The adsorption equilibria of carbon dioxide, methane and nitrogen are particularly important to the development of industrial pressure swing adsorption processes intended to separate CO2 and N2 from a variety of conventional as well as unconventional natural gas sources. The adsorption equilibrium capacities of gas mixtures needed for process design and simulation are often predicted from pure component adsorption data using various models including the ideal adsorbed solution theory (IAST). In this work, we present the adsorption equilibrium capacity data for a ternary gas mixture of CO2, CH4 and N2 as well as pure and binary gas mixtures of the same components on a commercial zeolite 13X, measured at temperatures of (273, 303 and 333 K) and pressures from (25 to 900 kPa) using a dynamic column breakthrough (DCB) apparatus. Although previous adsorption studies have reported the adsorption equilibria of pure and to a lesser degree binary gas mixtures on zeolite 13X, no experimental data are available in the literature for a ternary gas mixture of CO2, CH4 and N2 on zeolite 13X APG-III, a promising adsorbent for carbon capture and natural gas separation. The measured pure component adsorption capacities were regressed to a Toth isotherm model and the obtained Toth parameters were used to implement an IAST model for binary and ternary adsorption predictions. The IAST predictions of mixture gas adsorption represented the binary and ternary adsorption equilibria well with their corresponding maximum deviations being 0.055 and 0.3 mmol/g, respectively. This indicates the IAST can be applied successfully to these adsorption systems even though they involve molecules with different adsorption affinity and adsorbents with heterogeneous surfaces.
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Adsorption (2018) 24:381–392
https://doi.org/10.1007/s10450-018-9952-3
Binary andternary adsorption equilibria for CO2/CH4/N2 mixtures
onZeolite 13X beads from273 to333K andpressures to900kPa
GhazalAvijegon1· GongkuiXiao1· GangLi1· EricF.May1
Received: 30 December 2017 / Revised: 25 April 2018 / Accepted: 30 April 2018 / Published online: 9 May 2018
© Springer Science+Business Media, LLC, part of Springer Nature 2018
Abstract
Reliable adsorption equilibrium data and theoretical models for their accurate representation are crucial to the design of any
adsorption based separation. The adsorption equilibria of carbon dioxide, methane and nitrogen are particularly important
to the development of industrial pressure swing adsorption processes intended to separate CO2 and N2 from a variety of
conventional as well as unconventional natural gas sources. The adsorption equilibrium capacities of gas mixtures needed
for process design and simulation are often predicted from pure component adsorption data using various models including
the ideal adsorbed solution theory (IAST). In this work, we present the adsorption equilibrium capacity data for a ternary gas
mixture of CO2, CH4 and N2 as well as pure and binary gas mixtures of the same components on a commercial zeolite 13X,
measured at temperatures of (273, 303 and 333K) and pressures from (25 to 900kPa) using a dynamic column breakthrough
(DCB) apparatus. Although previous adsorption studies have reported the adsorption equilibria of pure and to a lesser degree
binary gas mixtures on zeolite 13X, no experimental data are available in the literature for a ternary gas mixture of CO2, CH4
and N2 on zeolite 13X APG-III, a promising adsorbent for carbon capture and natural gas separation. The measured pure
component adsorption capacities were regressed to a Toth isotherm model and the obtained Toth parameters were used to
implement anIAST model for binary and ternary adsorption predictions. The IAST predictions of mixture gas adsorption
represented the binary and ternary adsorption equilibria well with their corresponding maximum deviations being 0.055
and 0.3mmol/g, respectively. This indicates the IAST can be applied successfully to these adsorption systems even though
they involve molecules with different adsorption affinity and adsorbents with heterogeneous surfaces.
Keywords Carbon dioxide· Zeolite 13X APG-III· Ternary adsorption· Dynamic column breakthrough· IAST
1 Introduction
The separation of CO2 and N2 from CH4 containing gas mix-
tures is an essential step in many industrial applications such
as upgrading wellhead natural gas to pipeline gas specifi-
cations (Watson etal. 2011), ensuring the safe production
and storage of liquefied natural gas (LNG) (Kidnay etal.
2011), and promoting the commercialisation of sub-quality
reservoirs that comprise a significant portion of the reserves
world-wide (Rufford etal. 2012). In recent years, pressure
swing adsorption (PSA) technology has attracted much
attention for the separation of CO2 and N2 from CH4 due to
its potential in lowering the separation cost (Rufford etal.
2012; Saleman etal. 2017; Xiao etal. 2016).
For a PSA separation, the mixture gas adsorption equi-
librium data are essential to the design and simulation of
the process. However, there are limited literature data for
experimental mixture gas adsorption equilibrium because
the measurement of such data is still one of the most chal-
lenging experiments in adsorption research (Walton and
Sholl 2015). Instead, multicomponent adsorption data used
for design or simulation are often predictions from various
models basedonly onpure component adsorption experi-
ments. The ideal adsorbed solution theory (IAST) developed
by Myers and Prausnitz (1965) is the most widely used and a
generally reliable method for predicting mixture adsorption
using only pure component adsorption isotherms (Walton
Electronic supplementary material The online version of this
article (https ://doi.org/10.1007/s1045 0-018-9952-3) contains
supplementary material, which is available to authorized users.
* Eric F. May
Eric.May@uwa.edu.au
1 Fluid Science & Resources Division, Department
ofChemical Engineering, The University ofWestern
Australia, 35 Stirling Highway, Perth, WA6009, Australia
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
... times less than what was predicted by IAST at 0, 30 and 50 • C at pressures between 1.06 to 9.03 bar [48]. ...
... The measured CH 4 µDCB data all display a positive deviation from IAST, which again was expected [7,48]. The EES model is able to predict the measured data better than IAST. ...
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