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Colloquium Prof. Richon Paris, September 3Colloquium Prof. Richon Paris, September 3--4, 20094, 2009
Gas Solubility and Volumetric Behaviour ofCarbon Dioxide + Lubricant Systems
Josefa.Fernandez@usc.esThermophysical Properties Laboratory,University of Santiago de Compostela, Spain
Josefa Fernández
Dr. Olivia Fandiño
Ms. Teresa Regueira
Dr. Luis Lugo
Dr. Enriqueta Lopez
Dr. María J. P. Comuñas
Dr. Alfonso Pensado
Dr. Josefa García
Density of lubricants and their CO2 mixtures
Experimental technique
Results
Index
Density Solubility ConclusionsIntroduction
Introduction
Solubility of CO2 in lubricants
Experimental technique
Results
Conclusions
Introduction Density Solubility Conclusions
Environmental problemsOzone Depletion
Problem CO2 Systems of refrigeration Products
Global warming
Colloquium Prof. Richon Paris, September 3Colloquium Prof. Richon Paris, September 3--4, 20094, 2009
Introduction Density Solubility Conclusions
CO2 AS ALTERNATIVE REFRIGERANT
Natural refrigerant: low cost
Low GWP (Global Warming Potential )
GWP(HFC) ≈1000·GWP(CO2)
Null ODP (Ozone Depletion Potential )
No flammable
Slight or no toxic action
High thermal conductivity
Low critical temperature: 30.976 ºC
High working pressure (Critical pressure: 73.77 bar)
Problem CO2 Systems of refrigeration Products
o6
Diapositive 4
o6 La principal ventaja de la utliización del CO2 como refrigerante alternativo es su bajo coste, puesto que como todos sabemos es un productonatural que no necesita de síntesis.Además, una molécula de dióxido de carbono contribuye al calentamiento global unas 1000 veces menos que una molécula de HFC (que sonlos actuales refrigerantes en uso). Otra característica importante es que el CO2 tiene un potencial de destrucción de la capa de ozono nulo.Otras ventajas son la no inflamabilidad y su muy baja toxidad.A todo esto debes añadir que este fluido presenta una alta conductiv idad térmica.
Como contraindicaciones, señalar que posee un muy baja temperatura crítica, lo que ha obligado a rediseñar los ciclos de refrigeración,dando lugar a los ciclos transcríticos. Por otro lado resaltar la necesidad de utilizar mayores medidas de seguridad en estos equipos que lapresión de trabajo para los equipos que trabajan con CO2 es mucho más elevada que la de los aparatos que utilizan HFCs.Finalmente decir que estas contraindicaciones ya han sido superadas porque ya se están probando máquinas que emplean el CO2 comorefrigerante.Olivia, 4/22/2009
Introduction Density Solubility Conclusions
Problem CO2 Systems of refrigeration Products
Basic diagram of a refrigeration circuit
)
“The choice of lubricant has a great
impact on energy efficiency, reliability,
lifetime and noise levels of various
refrigeration systems”
High solubility of the refrigerant
Viscosity wear Performance
Heat transfercoefficients
Viscosity gradesAntiwear additives
Introduction Density Solubility Conclusions
Basic circuit for CO2
Oil accumulationHeat transfer coefficients
Phase separationPoor oil return
Compressor wear
Oil accumulation
Introduction Density Solubility Conclusions
Basic circuit for CO2
High MiscibilityHigh Miscibility
Presence of compressor oil in cooling system
Presence of refrigerant dissolved in the lubricant
ImmiscibilityImmiscibility
No return of oil to the compressor
Accumulation of oil within the circuit
Barotropic effect (density inversion of the phases)
Problems in refrigeration systems
Introduction Density Solubility Conclusions
Problem CO2 Systems of refrigeration Products
Lubricant Miscibilitywith CO2
Mineral oils Immiscible
PAOs Immiscible
Alkylbenzenes Immiscible
Ester Miscible
PAG PartiallyMiscible
0.7
0.8
0.9
1.0
1.1
10 20 30 40 50 60
p/MPa
r/g
·cm
-3
CO2 con 8% PEC9
PEC9
CO2
Pensado et al. J. Sup. Fluids 2007T=303.15 K
Introduction Density Solubility Conclusions
0
25
50
75
100
0 0,2 0,4 0,6 0,8 1
Oil Content
Tem
pera
ture
[°C
] p = 40 bar
p = 50 bar
p = 60 bar
Temperatura de saturación CO2-aceiteFauser et al. VTMS6 ConferenceConference 2003
0.05
0.08
0.10
0.13
0.15
20 30 40 50 60 70 80 90
T/ºC
h/m
Pa·
s
CO2 con 8% PEB8
CO2 puro
CO2 + 8% PEC5
0.05
0.08
0.10
0.13
0.15
20 30 40 50 60 70 80 90
T/ºC
h/m
Pa·
s
CO2 con 8% PEB8
CO2 puro
CO2 + 8% PEC5
Pensado et al.Pensado et al. J. Sup.J. Sup. FluidsFluids 20072007
p=25 MPa
Vaporization TemperatureFauser et al. VTMS6 ConferenceConference 2003
The thermophysical properties of the circulating fluid (refrigerant withsmall quantíties of the lubricant) are different of the pure refrigerant:tranfer coeficient, viscosity, vaporization temperature, enthalpy,….Similarly, the real lubricant has different properties than the purelubricant.
Name Pure SubstanceMw
g·mol-1
Pentaerythritol esters
PEC5 Pentaerythritol tetrapentanoate 472.61
PEC7 Pentaerythritol tetraheptanoate 584.82
PEB8 Pentaerythritol 2-ethylhexanoate 640.93
PEC9 Pentaerythritol tetranonanoate 697.04
Introduction Density Solubility Conclusions
Problem CO2 Systems of refrigeration Products
Indications POE. For medium an big refrigeration systems, for semi-hermetic compressors
Name Pure SubstanceMw
g·mol-1
DiPentaerythritol esters
DiPEC5 Dipentaerythritol hexapentanoate 758.98
DiPEC7 Dipentaerythritol hexaheptanoate 927.29
DiPEiC9 Dipentaerythritol hexaisononanoate 1095.61
Introduction Density Solubility Conclusions
Problem CO2 Systems of refrigeration Products
Viscosities of DIPEs are around ten times bigger that those of PEs.
Pensado et al. Ind. End. Chem. Res 2006a 2006b
Introduction Density Solubility Conclusions
Name SubstanceMw
g·mol-1
Polyalkylene glycols
PAG1 Poly(propylene glycol) dimethyl ether ~ 1700
PAG2 Poly(propylene glycol) dimethyl ether ~ 1400
PAG3 Poly(propylene glycol) monomethyl ether ~ 1200
Problem CO2 Systems of refrigeration Products
Small polymers or propylene oxide are used in refrigeration mainly in automotive airconditioning and heat pumps.
Introduction Density Solubility Conclusions
Name of mixture Components Viscosity (mPa·s)
PEB8 + PEC5 PEB8 and PEC5 32
PEB8 + PEC7 PEB8 and PEC7 32
POE0 From PEC5 to PEC9 32
POE1From PEC5 to PEC9
From DiPEC5 to DiPEC968
POE2From PEC5 to PEC9
From DiPEC5 to DiPEC9100
POE3 From DiPEC5 to DiPEC9 220
POE4 From TMPC16 to TMPC20 91
Problem CO2 Systems of refrigeration Products
TMP
j
p1
Colloquium Prof. Richon Paris, September 3Colloquium Prof. Richon Paris, September 3--4, 20094, 2009
Density of lubricants and their CO2 mixtures
Experimental technique
Results
Index
Density Solubility ConclusionsIntroduction
Introduction
Solubility of CO2 in lubricants
Experimental technique
Results
Conclusions
Colloquium Prof. Richon Paris, September 3Colloquium Prof. Richon Paris, September 3--4, 20094, 2009
Solubility ConclusionsIntroduction Density
Experimental technique
Mechanical oscillator densimeter
DMA HPM
Colloquium Prof. Richon Paris, September 3Colloquium Prof. Richon Paris, September 3--4, 20094, 2009
Solubility ConclusionsIntroduction Density
Experimental technique
278.15 K < T < 373.15 KLagourette et al. (1992)
Vacuum and water
T ≥ 373.15 KLagourette et al. modified by Comuñas et al. JCED (2008)
Vacuum, water and n-decane
),(),(),(),( 2 pTBpTpTApT
),( pTA
Calibration
)MPa1.0,T(B)0,T(B
O1
Diapositive 16
O1 Poner 0 K me parecía un poco exagerado.
Quizás quedaría mejor poner T< 373.15 KOlivia, 8/28/2009
Solubility ConclusionsIntroduction Density
Experimental technique
2
1
2
0
2
0
2
2
2
2
2
u
TAu
TAu
TATAU w
w
w
w
2
1
2
0
2
02
2
222
222
2
u
TAu
TAu
TATAU
w
w
w
ww
w
pTBTA ,2
Uncertainty Calculation
T < 373.15 K : Vacuum and water
Applying the uncertainty propagation law:
TT
TTA
vacuumw
w
22 MPa1.0,
MPa1.0,
Solubility ConclusionsIntroduction Density
Experimental technique
B(T,p) can be written as:
Applying the uncertainty propagation law:
2
1
2
0
2
0
2
2
2
2
,,,2,
u
pTBu
pTBu
pTBpTBU w
w
w
w
2
1
02
22202
22202
22 )(2)(21
)(2,
u
TAu
TAu
TApTBU
w
ww
w
ww
w
w
Uncertainty Calculation
pTpTTApTB ww ,,, 2
),(),(
MPa1.0,
MPa1.0,, 2
20
2pTpT
TT
TpTB ww
w
w
Solubility ConclusionsIntroduction Density
Experimental technique
Units Estimate Divisor u(x)kg/m3
u(ref) Referencematerial
kg/m3 0.01 3 0.006
Calibration 0.020 2
Resolution 0.010 23 0.0025u(T)
Repeatability
K
0.005 1
Calibration 0.02 2Resolution 0.01 23 0.014u(p)
Repeatability
MPa
0.01 1
u() Repeatability s 5 10-4 1 0.0075
Resolution 1 10-3
23U(A(T)) kg/m3
s2 k=2 7 10-8
Uncertainties: A(T)
2
1
2
0
2
02
2
222
222
2
u
TAu
TAu
TATAU
w
w
w
ww
w
EA_4/02 Guide
Expression of the Uncertainty of Measurement in Calibration, European Cooperation forAccreditation, EA-4/02, 1999.
Colloquium Prof. Richon Paris, September 3Colloquium Prof. Richon Paris, September 3--4, 20094, 2009
Solubility ConclusionsIntroduction Density
Experimental technique
Uncertainties: B(T,p)
EA_4/02 Guide
2
1
02
22202
22202
22 )(2)(21
)(2,
u
TAu
TAu
TApTBU
w
ww
w
ww
w
w
Units Estimate Divisor u(x)kg/m3
u(ref) Referencematerial
kg/m3 0.01 3 0.006
Calibration 0.020 2
Resolution 0.010 23 0.0025u(T)
Repeatability
K
0.005 1
Calibration 0.02 2Resolution 0.01 23 0.014u(p)
Repeatability
MPa
0.01 1
u() Repeatability s 5 10-4 1 0.0075
Resolution 1 10-3
23U(B(T,p)) kg/m3 k=2 0.5
kg/m3
Colloquium Prof. Richon Paris, September 3Colloquium Prof. Richon Paris, September 3--4, 20094, 2009
Solubility ConclusionsIntroduction Density
Experimental technique
pTBTA ,2
2
1
2
2
22
2
2
,,
2
pTBu
pTBuTAu
TAU
21
222222 ,22 pTBuuATAuU
Uncertainties: ρ
Applying the uncertainty propagation law:
Segovia et al. J. Chem. Thermodyn., 41, 632, 2009.
Colloquium Prof. Richon Paris, September 3Colloquium Prof. Richon Paris, September 3--4, 20094, 2009
Solubility ConclusionsIntroduction Density
Experimental technique
EA_4/02 Guide
21
222222 ,22 pTBuuATAuU 0.7 kg·m-3 (T<373.15 K, and p ≥0.1 MPa)
5 kg·m-3 (T=(373.15 and 398.15) K, and p =0.1 MPa)
3 kg·m-3 (T=(373.15 and 398.15) K, and p >0.1 MPa)(k=2)
u(x)Units Estimate Divisorkg/m3
u() Repetibility s 5 10-4 1
Resolution 1 10-3
230.0075
u(A(T)) kg/m3s2 7 10-8 2 0.25
u(B(T,p)) kg/m3 0.5 2 0.25
u() kg/m3 k=1 0.35
U() kg/m3 k=2 0.7
U() kg/m3/kg/m3 k=2 8 10-4
Segovia et al. J. Chem. Thermodyn., 41, 632, 2009.
Expression of the Uncertainty of Measurement in Calibration, European Cooperation forAccreditation, EA-4/02, 1999.
Solubility ConclusionsIntroduction Density
Experimental technique
Toluene: 283.15-398.15 K up to 70 MPa
() Cibulka and Takagi. J.Chem. Eng. Data, 1999,44, 411-429.
() Assael et al. Int. J.
Thermophys., 2001, 22,789-799.
() Lemmon and Span. J.Chem. Eng. Data, 2006,51, 785-850.
Bias (%) AAD (%) Dmax (%)
Cibulka and Takagi 0.002 0.03 0.09
Assael et al. 0.04 0.05 0.13
Lemmon and Span 0.02 0.03 0.08
DMA HPM: experimental deviations
Solubility ConclusionsIntroduction Density
Experimental technique
AAD %
0.06
0.02
0.03
0.03
( ) Cibulka and Takagi. J. Chem. Eng. Data, 1999, 44, 411-429.
() Lemmon and Span. J. Chem. Eng. Data, 2006, 51, 785-850.
(●) Troncoso et al. J. Chem. Eng. Data, 2004, 49, 923-927.
() Zúñiga-Moreno et al. J. Chem. Eng. Data, 2005, 50, 1030-1037.
DMA HPM: experimental deviationsn-Decane: 283.15-398.15 K up to 130 MPa
Solubility ConclusionsIntroduction Density
Experimental technique
Correction due to the viscosity for HPM densimeter
4105.7
HPM
HPM
4101627.04482.0
HPM
HPM
Fandiño et al. J: Chem. Thermodyn. 2009, ASAP
Solubility ConclusionsIntroduction Density
Experimental technique
4
512
512 1045.05.0
P
realP
DMA 512P
• η<100 mPa·s
• η>400 mPa·s
4
512
512 105
P
realP
4105.7
HPM
HPM
4101627.04482.0
HPM
HPM
• η<289 mPa·s
DMA HPM
• η>289 mPa·s
DMA HPM
DMA 512P
DMA 602H
DMA HPM
DMA 512P
DMA 602H
Correction due to the viscosity for several densimeters
Solubility ConclusionsIntroduction Density
Experimental technique
Squalane: 298.15-398.15 K up to 60 MPawith correction term due to the viscosity
(□) Fandiño et al. J. Chem. Eng.Data, 2005, 50, 939-946
() Kuss y Taslimi. Chem. Ing.Tech., 1970, 42, 1073-1081
(♦) Fermeglia y Torriano. J.Chem. Eng. Data, 1999, 44,965-969
() Kumagai et al. Int. J.Thermophys., 2006, 27,376-393
Bias (%) AAD (%) Dmax (%)
Kuss and Taslimi 0.02 0.03 0.05
Fandiño et al. -0.02 0.02 0.03
Kumagai et al. 0.08 0.09 0.19
Fermeglia and Torriano 0.005 0.005 0.005
DMA HPM: experimental deviations
Solubility ConclusionsIntroduction Density
Results
Fandiño et al. J. Chem. Eng. Data 2005, Green Chemistry 2006, Ind. Eng. Chem. Res. 2006
Solubility ConclusionsIntroduction Density
rr(alkanes)<<(alkanes)<< rr(POE4) <(POE4) < rr(PEs)(PEs) < r(DiDP) < r(PAG) << rr(DiPEs)(DiPEs)
Summary Density for all Fluids
-COO- r
For esters
-CH2- r
Branched r
For endcapped PAGs
-PO- r
Solubility ConclusionsIntroduction Density
Results
kkTT(POE4) <(POE4) < kkTT((DiDPDiDP) <) < kkTT((DiPEDiPE)) < kkTT(PEPE) < kkTT(PAGPAG) << kkTT(alkanes)
Isothermal Compressibility
-COO- kT
For PEs, DiPEs
-CH2- kT
Branched kT
For endcapped PAGs
-PO- kT
323,15 K
Solubility ConclusionsIntroduction Density
Results
Isobaric Thermal Expansivity
PAG1
Crossing pointThe crossing point of theisothermal of ap has beenfound for the most of the
fluids except for the DiPEs.
aapp(DiPE)<(DiPE)< aapp(POE4) <(POE4) < aapp(DiDP)(DiDP) < aapp(PAG) << aapp(alkanes)
-COO- ap??
For PEs, DiPEs,alkanes
-CH2- ap
Branched ap
For PAGs (dialkylated)
-PO- ap
323,15 K
High PressureDensimetry
Solubility ConclusionsIntroduction Density
Lubricant + Refrigerant MixturesB)
Solubility ConclusionsIntroduction Density
Experimental technique
The sample is a mixture of two components:
lubricant: liquid at atmospheric pressure
refrigerant: gas at atmospheric pressure
Transfer the sample must be carried outthrough enclosed recipient
Solubility ConclusionsIntroduction Density
Experimental technique
The new transfersystem
Measurements: DMA HPM
Solubility ConclusionsIntroduction Density
Experimental technique
Syringe pumpsSyringe pumps
Teledyne ISCOTeledyne ISCO
Grove regulatorGrove regulator
PressurePressurelimiting valvelimiting valve
Thermostatic bathsThermostatic baths
Transfer system
Solubility ConclusionsIntroduction Density
Experimental technique
Transfer system
Thermostatic bathsThermostatic baths
i
iii
M
pTn
)·,(
Moles of the fluid i in time unit
Grove regulatorGrove regulator
PressurePressurelimiting valvelimiting valve
Syringe pumpsSyringe pumps
Teledyne ISCOTeledyne ISCO
Solubility ConclusionsIntroduction Density
Experimental technique
Units Estimation Divisoru(x)
xCO2≤0.8 xCO2
≥0.8
u(T) K 0.5 √3 0.0003 0.0004
u(p) MPa 0.05 √3 8·10-5 4·10-5
u(rCO2) 0.05% r 2 0.0001 2·10-5
u(fCO2) 0.5% f 2 0.001 0.0004
u(ri) kg·m-3 0.7 2 0.0001 2·10-5
u(fi) 0.5% f 2 0.001 0.0004
u(xCO2) 0.002 0.001
U(xCO2) (k=2) 0.004 0.002
Uncertainties: mole fraction
Expression of the Uncertainty of Measurement in Calibration, European Cooperation forAccreditation, EA-4/02, 1999.
EA_4/02 Guide
Solubility ConclusionsIntroduction Density
Results
Uncertainty AAD (%)
Zúñiga-Moreno et al. (2005) 0.2 kg·m-3 0.1
Bessières et al. (2001) 0.2 kg·m-3 0.1
Cullick and Mathis (1984) 0.5 kg·m-3 0.2
Crossing point of lines of
constant concentration
x Carbon dioxide + (1-x) n-decane
Solubility ConclusionsIntroduction Density
Results
x Carbon dioxide + (1-x) n-decane
),(
1
),(
1)1(
),(
1
),(
1),,(
2
2 pTpTMx
pTpTMxxpTv
oil
oil
CO
COE
For T>314 K is not correct to name excessproperties since the CO2 is a supercritical fluid
(,, ,) Zúñiga-Moreno et al. J. Chem. Eng. Data, 2005, 50, 1030-1037.
() Bessières et al. J. Chem. Eng. Data, 2001, 46, 1136-1139
Colloquium Prof. Richon Paris, September 3Colloquium Prof. Richon Paris, September 3--4, 20094, 2009
Solubility ConclusionsIntroduction Density
Results
x CO2 + (1-x) DiPEC5
0.92
0.97
1.02
1.07
1.12
0 20 40 60 80 100 120
p, MPa
r,g
·cm
-3
398.15 K
278.15 K
0.1 MPa – 120 MPap
278.15 K – 398.15 KT
x= 0x= 0.209x= 0.597
x= 0.209
Colloquium Prof. Richon Paris, September 3Colloquium Prof. Richon Paris, September 3--4, 20094, 2009
Solubility ConclusionsIntroduction Density
Results
x CO2 + (1-x) DiPEC5
0.2
0.4
0.6
0.8
1.0
1.2
0 20 40 60 80 100 120p, MPa
r,
g·c
m-3
0.94
0.98
1.02
1.06
1.10
1.14
273.15 303.15 333.15 363.15 393.15
T, K
r,
g·c
m-3
CO2
() x= 0.209
333.15 K x= 0.597
() x= 0.597
() x= 0
10 MPa
120 MPa
() x= 1
Solubility ConclusionsIntroduction Density
Results
0.000 0.301 0,701 0.984 1.000
Crossing point of lines of
constant concentrationSame behaviourfor other
asymmetricmixtures. as found
by Marchi et al.,Comuñas et al.
and Pensado et al.
x CO2 + (1-x) DiPEC7
Colloquium Prof. Richon Paris, September 3Colloquium Prof. Richon Paris, September 3--4, 20094, 2009
Solubility ConclusionsIntroduction Density
Results
CO2 + PEs
0.75
0.80
0.85
0.90
0.95
1.00
1.05
10 20 30 40 50 60
p / MPa
/g
·cm
-3
0.06
0.08
0.10
0.12
0.14
0.16
0.18
0.20
10 20 30 40 50 60
p / MPa
/m
Pa·
sat 303.15 K and 10 MPahPEB8 ~ 83 mPa·s
(■) xPEB8=0.0058
() xPEB8=0.0115
Pensado et al. J. Sup. Fluids 2007, AIChE 2008
Colloquium Prof. Richon Paris, September 3Colloquium Prof. Richon Paris, September 3--4, 20094, 2009
Solubility ConclusionsIntroduction Density
Results
CO2 + PEs
Pensado et al. J. Sup. Fluids 2007, AIChE 2008
Isothermal Compressibility
2
4
6
8
10
12
10 20 30 40 50 60
p / MPa
103
T/
MP
a-1
2
4
6
8
10
10 20 30 40 50 60
p / MPa
103
T/
MP
a-1
353.15 K
303.15 K
353.15 K
303.15 K
x PEB8 + (1-x) CO2
at 303.15 K and 15 MPakT CO2 ~ 13·10-3 MPa-1
kT PEB8 ~ 6·10-4 MPa-1
xPEB8 = 0.0058 xPEB8 = 0.0155
Colloquium Prof. Richon Paris, September 3Colloquium Prof. Richon Paris, September 3--4, 20094, 2009
Density of lubricants and their CO2 mixtures
Experimental technique
Results
Index
Density Solubility ConclusionsIntroduction
Introduction
Solubility of CO2 in lubricants
Experimental technique
Results
Conclusions
ConclusionsIntroduction Density
Experimental technique
Solubility
Ranges:
o Pressure 0.1 a 10 MPa
oTemperature 283-348 K
Isochoric technique
For non-volatile liquids
Fandiño et al. J. Chem. Eng. Data 2008, 53, 1854–1861
Whalström and Vamling J. Chem. Eng. Data 1999 44, 823–828.
ConclusionsIntroduction Density
Experimental technique
Solubility
PressureTransducer
CO2
V1
V2
V3
V4
V5
AuxiliaryThermostatic Bath
Gascylinder
Measurementcell
Lubricant
PC
ONOFF
Temperature
Transduce
CO2
V1
V2
V3
V4
V5
AuxiliaryThermostatic Bath
Environmental Chamber
Gascylinder
Measurementcell
Magnetic Stirrer
PCPC
ONOFF
VC Vacuumpump
±0.02 K
±0.003 MPa
283.15 ≤ T/K ≤ 348.15p/MPa ≤ 8.0
ConclusionsIntroduction Density
Experimental technique
Solubility
PressureTransducer
V1
V2
V3
V4
V5
AuxiliaryThermostatic Bath
PC
ONOFF
Temperature
Transduce
CO2CO2
V1
V2
V3
V4
V5
AuxiliaryThermostatic Bath
Environmental Chamber
Magnetic Stirrer
PCPC
ONOFF
VC
• Measured p, T for theCO2
• Known Vsystem
Equation of stateNumber of moles of
CO2 gas in the system
EquilibriumPressure const.
Temperature const.
Moles of CO2 absorbed in the lubricant =
= initial moles CO2 - moles CO2 gas equilibrium
)(. Tv absCO2
),(
)(1
),(
)()(
),(
)(
),(
)(
.
..
.
..
..
....
2
2
222
pTv
Tv
pTv
TVTV
pTv
TV
pTv
TV
n
l iqeqvCO
liqeqabsCO
liqeqvCO
liqeqliql iqeqcélula
gassisteqvCO
gassisteqgassist
inicinicvCO
inicgassist
g
),( pTvvCO2
)(. TV gassis
)T(Vcell
),( pTVliq
Volume of system gas
Volume of measurement cell
Volume of lubricant inside of measurement cell
Mole volume of CO2 in vapour phase
Mole volume of CO2 absorbed
ConclusionsIntroduction Density
Experimental technique
Solubility
Calculations
ggasg nMm
Solubility ConclusionsIntroduction Density
Experimental technique
Estimation Unitsu(x)
Low xCO2High xCO2
u(T) 0.02 K 0.0003
u(p) 0.0007 MPa 0.001 0.0001
u(rl) 0.0002 g·cm-3 2·10-5
u(vvg) 0.04% g·cm-3 0.0009
u(ml) 0.004 g 2·10-5
u(Vsist. gas) 0.1 cm-3 0.001 0.0001
u(Vmeas. cell) 0.2 cm-3 0.002 0.0001
u(Vgas abs) 50% cm-3 0.0004 0.007
u(xCO2) k=1 0.003 0.007
U(xCO2) k=2 0.006 0.01
U(xCO2) % k=2 6 2
Uncertainties: mole fraction
Colloquium Prof. Richon Paris, September 3Colloquium Prof. Richon Paris, September 3--4, 20094, 2009
Results
ConclusionsIntroduction Density Solubility
Vapor Pressures
-22
-20
-18
-16
-14
-12
-10
0.0020 0.0022 0.0024 0.0026 0.0028 0.0030 0.0032
1/T(K)
lnP
(bar)
PEC5
PEC7
PEC9
PEB8
Símbolos: puntos experimentales
(Razzouk et al. 2007)PC-SAFT
Razzouk et al. / Fluid Phase Equilibria 260 (2007) 248–261
Results
ConclusionsIntroduction Density Solubility
xCO2(PEC5) <xCO2
(PEC7) <xCO2(PEB8) <xCO2
(PEC9)
x CO2 + (1-x) PE
Comparison with literature
ConclusionsIntroduction Density Solubility
Results
AAD with
Bobbo et al.
IIR Conferences in Vicenza(2005)
2%
xCO2(PECn) ≈xCO2
(PEBn)
Comparison with literature
ConclusionsIntroduction Density Solubility
Results
PEC4. Bobbo et al. (2005)PEC5 PEBM5. Bobbo et al. (2007)PEC6. Bobbo et al. PEBM6. Bobbo et al. (2007) PEC7 PEBM7. Bobbo et al. (2007)
PEB8 Castrol Icematic SW32. Bobbo et al. (2006)
wCO2(PECn) < wCO2
(PEBn)
n wCO2(PECn)
Results
ConclusionsIntroduction Density Solubility
PEC7 PEB8DiPEC7PAG2 POE ISO56. Marcelino-Neto (2006) PAG. García et al. (2008) Squalane. Kukova (2003)
POE3
Colloquium Prof. Richon Paris, September 3Colloquium Prof. Richon Paris, September 3--4, 20094, 2009
ConclusionsIntroduction Density Solubility
Results
Ley de Raoult
Negative deviations show the presence of strongerinteractions between unlike molecules in the mixture
satii pxp CO2+PEs
A2
Diapositive 60
A2 La solubilidad aumenta ligeramente con la masa molecular de los aceites estudiados. El efecto es inverso pero mas claro si se observa enporcentaje en peso. Esto también ha sido encontrado por Bobbo y co. como veremos a continuación.
La solubilidad es mayor que la ideal. Desviación negativa de la ley de Raoult. (Ver que implicaciones tiene).avi, 9/7/2006
ConclusionsIntroduction Density Solubility
Results
experimental (Hauk 2001)PC-SAFT kij(T),
Garcia et al. J Sup. Fluids 2007,2008
0 0.2 0.4 0.6 0.8 1
fracción en peso de CO2 en PAG2
0
2
4
6
8
10
12
14
16
18
Pre
sió
n/M
Pa
CO2 + PAG2 (a)
278.15 K
298.15 K
31
3.1
5K
37
3.1
5K
ELLV
230
255
280
305
0 20 40 60 80 100
masa de CO2 % en PAG2
T/K
Fin ELLV
(b)
inmiscibleinmisciblemisciblemiscible
We have implemented a computer-operated-densimetricequipment and evaluated of the density uncertainty usingthe EA-4/02 Guide:
.
With (k=2),0.7 kg·m-3 (T<373.15 K, and p≥0.1 MPa)5 kg·m-3 (T=(373.15 and 398.15) K, and p=0.1 MPa)3 kg·m-3 (T=(373.15 and 398.15) K, and p>0.1 MPa)
We have presented a new loading system for gas + liquidcompressed systems, which consists in two syringe pumpsISCO Teledyne with electronic valves which deliver the gasand the liquid pure components at programmable constantflow rates.
New pVTx values were obtained for binary CO2 + (decane,
DiPEC7, DiPEC5) are presented.
Introduction Density Solubility Conclusions
Introduction Density Solubility Conclusions
The uncertainties of the solubility measurementsobtained, following the guide EA-4/02, are smaller than6% to low xCO2
and 2% to high xCO2
The solubility increases with the pressure and decreaseswith the temperature to all mixtures.
The solubilities, expressed in terms of mole fractions, donot change practically with the branching and the size ofthe acid chains
Negative deviations of Raoult’s law Strong interactionsbetween different fluids due to important quadrupolemomentum of the CO2
xPEs < xDiPEC7 < xPAG2
Dr. Steve J. Randles, UNIQEMA (now Croda)
• Prof. Agilio Padua, University Blaise Pascal
• Prof. Jacques Jose, Dra Mokbel and Razzouk, Un. Lyon 1
• Dr. M. Youbi-Iddrissi, Cemagref, Paris
• Prof. José Juan Segovia, University of Valladolid
• Ministerio Educación y Ciencia
• Xunta de Galicia
ACKNOWLEDGEMENTS
Colloquium Prof. Richon Paris, September 3Colloquium Prof. Richon Paris, September 3--4, 20094, 2009
Gas absorbed volume
1- Estimations
Experimental techniqueConclusionsIntroduction Solubility
Results
12
1
1
11 35,2095.0c
c
c
c
Tc
Tp
RT
Vp
Brelvi and O’Connell. AlChE J., 1972, 18, 1239-1243
Zellner et al. Ind. Eng. Chem. Fundam., 1970, 9, 549-564
Heidemann y Prausnitz. Ind. Eng. Chem. Process Des.
Dev., 1977, 16, 375-381