Cycle Development and Process Optimization of
High-purity Oxygen Production using
Silver-Exchanged Titanosilicates (Ag-ETS-10)
Sayed Alireza Hosseinzadeh Hejazi, Libardo Estupinan Perez, Arvind
Rajendran,
∗and Steven Kuznicki
Department of Chemical and Materials Engineering, University of Alberta, 12th Floor, Donadeo Innovation Centre for Engineering (ICE), 9211 - 116 Street, Edmonton, Alberta,
CANADA, T6G 1H9
E-mail: *[email protected]
Table S1: Reported Henry’s law selectivity of adsorbents showing Ar/O2 selectivity.
Adsorbent Ar/O2 Temperature Reference
selectivity [K]
CMS 0.81-0.93 293.15 K Jin et al.1
VA-class hydrophobic
dipeptides
1.3 278.15 K Afonso et al.2
Ag-Mordenite 1.17-1.19 303.15 K Sebastian and Jasra3
Ag-ZSM-5 1.11-1.29 303.15 K Sebastian and Jasra3
Ag-X 1.11 303.15 K Sebastian and Jasra3
Ag-LiLSX 1.14 298.15 K Ferreira et al.4
Ag-ETS-10 binderless 1.41-1.49 303.15 K Anson et al.5 and Shi et
al.6
Ag-ETS-10 with binder 1.39 303.15 K This study
Table S2: Fitted Langmuir adsorption parameters for N2, O2, and Ar on Ag-ETS-10 at low pressure. Parameter N2 Ar O2 b0 (m3 mol-1) 3.02 × 10−6 8.35 × 10−6 1.27 × 10−5 qs (mol kg-1) 0.53 0.53 0.53 −∆Ui (kJ mol-1) 26.34 18.82 16.93 S3
Table S3: Equations for modeling adsorption column dynamics.
overall mass balance
1 P ∂P ∂t − 1 T ∂T ∂t = − T P ∂ ∂z P Tv −RT P 1 − ncomp X i=1 ∂qi ∂t (1)
component mass balance
∂yi ∂t + yi P ∂P ∂t − yi T ∂T ∂t = T PDL ∂ ∂z P T ∂yi ∂z −T P ∂ ∂z yiP T v −RT P 1 − ∂qi ∂t (2) solid phase mass balance ∂qi
∂t = ki(q
∗
i − qi) (3)
mass transfer coeffcient ki=
15pDp r2 p (4) pressure drop −∂P ∂z = 150 4 1 r2 p 1 − 2 µv (5)
column energy balance
1 − ρsCp,s+ Cp,a ncomp X i=1 qi ! ∂T ∂t = Kz ∂2T ∂2z − Cp,g R ∂ ∂z(vP ) − Cp,g R ∂P ∂t − 1 − Cp,aT ncomp X i=1 ∂qi ∂t +1 − ncomp X i=1 (−∆Hi) ∂qi ∂t −2hin rin (T − Tw) (6) wall energy balance ρwCp,w
∂Tw ∂t = Kw ∂2T w ∂2z + 2rinhin r2 out− rin2 (T − Tw) − 2routhout r2 out− r2in (Tw− Ta) (7) S4
Table S4: Parameters used in cycle simulations and optimizations.
Parameter Value Source
Column properties
column length, L [m] 0.32 measured inner column radius, rin[m] 0.01805 measured
outer column radius, rout[m] 0.02415 measured
column void fraction, 0.32 measured particle voidage, p 0.35 assumed
extrudates dimensions [cm], dpand Lp 1.0 and 0.1 measured
tortuosity, τ 3 assumed
Properties and constants
universal gas constant, R [m3Pa mol-1K-1] 8.314 standard value
adsorbent particle density, ρs[kg m-3] 990 measured
column wall density, ρw[kg m-3] 7800 standard value for stainless steel
specific heat capacity, Cp,g[J kg-1K-1] 1041.3 (N2), 895.63 (O2) and 521.45 (Ar) standard values
specific heat capacity of adsorbed phase, Cp,a[J kg-1K-1] 1041.3 (N2), 895.63 (O2) and 521.45 (Ar) assumed
specific heat capacity of adsorbent, Cp,s[J kg-1K-1] 715.9 fitted
specific heat capacity of column wall, Cp,w[J kg-1K-1] 502 standard value for stainless steel
fluid viscosity, µ [kg m-1s-1] 1.801 × 10−5(N
2), 2.095 × 10 −5(O
2), and 2.291 × 10
−5(Ar) standard values
molecular diffusivity, Dm[m2s-1] 7.185 × 10−5(N2), 7.481 × 10−5(O2), and 7.614 × 10−5(Ar) standard values
effective gas thermal conductivity, Kz[J m-1K-1s-1] 0.0903 assumed
thermal conductivity of column wall, Kw[J m-1K-1s-1] 16 standard value for stainless steel
inside heat transfer coefficient, hin[J m-2K-1s-1] 15.2 fitted
outside heat transfer coefficient, hout[J m-2K-1s-1] 1462.1 fitted
0.5 0.4 0.3 0.2 0.1 0.0
Equilibrium Loading [mol/kg]
120 100 80 60 40 20 0 Pressure [kPa]60 80 100 120 40 20 0 30°C 50°C 70°C 'FitQN2-30' 'FitQN2-50' 'FitQN2-70' N2 303.15 K 323.15 K 343.15 K (a) 0.5 0.4 0.3 0.2 0.1 0.0
Equilibrium Loading [mol/kg]
120 100 80 60 40 20 0 Pressure [kPa] 303.15 K 323.15 K 343.15 K Ar (b) 0.5 0.4 0.3 0.2 0.1 0.0
Equilibrium Loading [mol/kg]
120 100 80 60 40 20 0 Pressure [kPa] 303.15 K 323.15 K 343.15 K O2 (c) 0.5 0.4 0.3 0.2 0.1 0.0
Equilibrium Loading [mol/kg]
120 100 80 60 40 20 0 Pressure [kPa] N2 Ar O2 T= 303.15 K (d)
Figure S1: Single component low pressure adsorption isotherms of a)N2, b)Ar, and c)O2
on Ag-ETS-10 extrudates. Symbols are experimental values and lines are fitted Langmuir model. (d) compares the isotherms of three gases at 303.15 K.
Figure S2: Results of process optimization to maximize O2 purity and recovery for 95.0%
O2/5.0% Ar as the feed. Experimental data* and column dimension for the simulations are
obtained form Ferreira et al.7
* The experimental data form Ferreira et al7 is based on the assumption that the value of recovery reported is for the O 2
purification stage alone.
Figure S3: Sensitivity analysis on the effect of operating conditions on O2 purity of the optimal point for the Skarstrom cycle. Blue and red bars represent the change in the purity due to +10% and -10% change in the corrosponding operating condition, respectively. The other operating conditions are kept constant while conducting the sensitivity analysis for each of the decision variables.
Figure S4: Sensitivity analysis on the effect of operating conditions on O2 recovery of the optimal point for the Skarstrom cycle. Blue and red bars represent the change in the recovery due to+10% and -10% change in the corrosponding operating condition, respectively. The other operating conditions are kept constant while conducting the sensitivity analysis for each of the decision variables.
Nomenclature
b0 parameter in Langmuir isotherm [m3 mol−1]
c fluid phase concentration [mol m−3]
Cpa specific heat capacity of the adsorbed phase [J mol−1 K−1]
Cpg specific heat capacity of the gas phase [J mol−1 K−1]
Cps specific heat capacity of the adsorbent [J kg−1 K−1]
Cpw specific heat capacity of the column wall [J kg−1 K−1]
DL axial dispersion [m2 s−1]
Dm molecular diffusivity [m2 s−1]
Dp macropore diffusivity [m2 s−1]
hin inside heat transfer coefficient [J m−2 K−1 s−1]
hout outside heat transfer coefficient [J m−2 K−1 s−1]
ki mass transfer coefficient [s−1]
Kw thermal conductivity of column wall [J m−1 K−1 s−1]
Kz effective gas thermal conductivity [J m−1 K−1 s−1]
L column length [m]
P pressure [Pa]
q solid phase concentration [mol kg−1]
qs saturation concentration in the solid phase [mol kg−1]
q∗ equilibrium solid phase concentration [mol kg−1]
R universal gas constant [Pa m3 mol−1 K−1]
rin column inner radius [m]
rout column outer radius [m]
rp particle radius [m]
T temperature [K]
Ta ambient temperature [K]
Tbath water bath temperature [K]
Tw column wall temperature [K]
t time [s]
U internal energy [J mol−1]
v interstitial velocity [m s−1]
y gas phase composition [-]
z axial coordinate [m]
Greek symbols
bed voidage [-]
p particle voidage [-]
µ fluid viscosity [kg m−1 s−1]
ρs adsorbent particle density [kg m−3]
ρw wall density [kg m−3]
τ tortuosity [-]
References
(1) Jin, X.; Malek, A.; Farooq, S. Production of Argon from an Oxygen-Argon Mixture by Pressure Swing Adsorption. Ind. Eng. Chem. Res. 2006, 45, 5775.
(2) Afonso, R.; Mendes, A.; Gales, L. Hydrophobic Dipeptide Crystals: A Promising Ag-free Class of Ultramicroporous Materials Showing Argon/Oxygen Adsorption Selectivity. Phys. Chem. Chem. Phys. 2014, 16, 19386.
(3) Sebastian, J.; Jasra, R. V. Sorption of Nitrogen, Oxygen, and Argon in Silver-Exchanged Zeolites. Ind. Eng. Chem. Res. 2005, 44, 8014.
(4) Ferreira, D.; Magalh˜aes, R.; Bessa, J.; Taveira, P.; Sousa, J.; Whitley, R. D.; Mendes, A.
Study of AgLiLSX for Single-Stage High-Purity Oxygen Production. Ind. Eng. Chem. Res. 2014, 53, 15508.
(5) Anson, A.; Kuznicki, S. M.; Kuznicki, T.; Haastrup, T.; Wang, Y.; Lin, C. C.; Sawada, J. A.; Eyring, E. M.; Hunter, D. Adsorption of Argon, Oxygen, and Nitro-gen on Silver Exchanged ETS-10 Molecular Sieve. Micropor. Mesopor. Mater. 2008, 109, 577.
(6) Shi, M.; Kim, J.; Sawada, J. A.; Lam, J.; Sarabadan, S.; Kuznicki, T. M.; Kuznicki, S. M. Production of Argon Free Oxygen by Adsorptive Air Separation on Ag-ETS-10. AIChE J. 2013, 59, 982.
(7) Ferreira, D.; Boaventura, M.; B´arcia, P.; Whitley, R. D.; Mendes, A. Two-Stage Vacuum
Pressure Swing Adsorption Using AgLiLSX Zeolite for Producing 99.5+% Oxygen from Air. Ind. Eng. Chem. Res. 2016, 55, 722
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