Post on 11-Aug-2020
Freezing Point Depression of Aqueous Solutions of DEEAFreezing Point Depression of Aqueous Solutions of DEEA, MAPA and DEEA‐MAPA with and without CO2 Loading
Muhammad Waseem ArshadMuhammad Waseem Arshad
Supervisor: Assoc. Prof. Kaj Thomsen
2nd ICEPE, 20‐22 June, 2011
PRESENTATION OUTLINE
IntroductionIntroduction
Materials
i h iReaction Mechanism
Experimental Methodp
Results
ConclusionsConclusions
Future Work
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INTRODUCTION
Freezing Point Depression:The phenomenon in which the freezing point of a LiquidThe phenomenon in which the freezing point of a Liquid(Solvent) is depressed when another compound is added in it.This means that the solution has lower freezing than the purelsolvent.
Why we need Freezing Point Depression Data???Why we need Freezing Point Depression Data???We want to model H2O‐DEEA‐MAPA‐CO2 systemWater activity is a key parameter for the amount of water
t d i th d bevaporated in the desorberLow water activity means less evaporation of water in thedesorber and low energy consumption during solventregenerationWater activity can be determined very accurately fromFreezing point data
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g p
MATERIALS
2‐(Diethylamino)‐ethanol OR DEEA (99%)l li id i h li h ll lClear liquid with light yellow colour
Freezing point = ‐70 oC
Boiling point = 163 oC g p
pH = 11.5 at 100 g/l at 20 oC
Completely soluble in water
3‐(Methylamino)propylamine OR MAPA (97‐98%)Clear and colourless liquid
Freezing point = ‐72 oC
Boiling point = 140 oCBoiling point = 140 oC
pH = 13.5 at 100 g/l at 20 oC
Completely soluble in water
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REACTION MECHANISM
2‐(Diethylamino)‐ethanol OR DEEA 2 5 R C HR CH CH OH
= −′ = − 2 2
2
DEEA
R CH CH OHR R N
=′∴ =
( )2 2 2 2 3 1R R N H O CO R R N H HCO+ −′ ′+ + → +
Base catalytic effect on hydration of CO2
( )
( )2 2 2 1R R N CO R R NCOO a−′ ′+ ↔Zwitterion mechanism
( )( )
2 2 2
2 2 2 3
1
1
R R N CO R R NCOO a
R R NCOO H O R R N H HCO b− + −
+ ↔
′ ′+ → +
( )2 3 2CO OH HCO− −+ ↔Following reactions may also take place simultaneously
( )2 2 3 3CO H O HCO H− ++ ↔ +
[Ref] Vaidya, P. D.; Kenig, E. Y. A Study on CO2 Absorption Kinetics by Aqueous Solutions of N,N‐Diethylethanolamine and N Ethylethanolamine Chem Eng Technol 2009 32 No 4 556 563
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Diethylethanolamine and N‐Ethylethanolamine. Chem. Eng. Technol. 2009, 32, No. 4, 556‐563
REACTION MECHANISM
3‐(Methylamino)propylamine OR MAPA
P t ti
3 6 3
2
and MAPA
R C H R CHH NRR NH
′= − = −′∴ =
( )( )
2 2 2
2 3
Protonation: 1
2
H NRR NH H H NRR NH
H NRR NH H H NRR NH
+ +
+ +
+ ↔′ ′
+ ↔′ ′ 8 Possible( )2 3
2 3 2 2 H NRR NH H H NRR NH+ + ++ ↔′ ′ ( ) 38 Possible species of MAPA
( )( )
2 2 2
2 2
Carbamate: 4
5H NRR NH CO H NRR NCOO HH NRR NH CO OOCHNRR NH H
− +
− +
+ ↔ +′ ′
+ ↔ +′ ′ ( )( )
2 2
2 2
5 2 2 6
H NRR NH CO OOCHNRR NH HH NRR NH CO OOCHNRR NCOO H− − +
+ ↔ +
+ ↔ +′ ′
2
Protonated Carbamate:H ( )
( )3 7
8NRR NCOO H H NRR NCOO
OOCHNRR NH H OOCHNRR NH
− + + −
− + − +
+ ↔′ ′
+ ↔′ ′
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( )2 8OOCHNRR NH H OOCHNRR NH+ ↔
EXPERIMENTAL METHOD
A, Thermostatic bath with ethanol
B, Cooling jacket
C, Sample glass with magnetic
stirrer
D, Rubber stopper with sample
glass lidglass lid
E, Device for manual stirring
F, Controlled temperature ethanol
bath with magnetic stirrer
G, Pt100 Thermometer
H, Data acquisition unit
Experimental Setup[Ref] Fosbøl, P. L.; Pedersen, M. G.; Thomsen, K. Freezing Point Depressions of Aqueous MEA, MDEA, and MEA‐
d h h l h h f
2nd ICEPE, 20‐22 June, 2011
MDEA Measured with a New Apparatus. J. Chem. & Eng. Data 2010, Special Issue: John M. Prausnitz Festschrift
7
EXPERIMENTAL METHOD
Measured Freezing Point
Heat of Crystallisation
Crystallisationy
[Ref] Fosbøl, P. L.; Pedersen, M. G.; Thomsen, K. Freezing Point Depressions of Aqueous MEA, MDEA, and MEA‐d h h l h h f
2nd ICEPE, 20‐22 June, 2011
MDEA Measured with a New Apparatus. J. Chem. & Eng. Data 2010, Special Issue: John M. Prausnitz Festschrift
8
RESULTS
Aqueous solutions of DEEA and MAPA
270
275
K)
265
erature (K
255
260
zing
Tem
pe
DEEA
250Freez
MAPA
245
0 2 4 6 8 10 12
Solvent Molality (mole / kg water)
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RESULTS
Aqueous solutions of DEEA‐MAPA with different molar ratios
270
275
265
rature (K)
255
260
ng Tem
per
DEEA
DEEA/MAPA 5:1
DEEA/MAPA 3:1
250Freezi DEEA/MAPA 1:1
DEEA/MAPA 1:3
DEEA/MAPA 1:5
MAPA
245
0 10 20 30 40 50 60
Solvent Mass Percent
2nd ICEPE, 20‐22 June, 2011
Solvent Mass Percent
10
RESULTS
Aqueous solutions of MAPA loaded with CO2
270
272
266
268
rature (K)
262
264
ng Tem
per
258
260
Freezi 10% MAPA
20% MAPA
27% MAPA256
0 0,2 0,4 0,6 0,8 1 1,2 1,4 1,6 1,8
CO2 Loading (mol CO2 / mol MAPA)
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RESULTS
Aqueous solutions of DEEA loaded with CO2
271
272
)
269
270
erature (K
)
267
268
zing
Tem
pe
265
266Freez
12% DEEA
20% DEEA
0 0,2 0,4 0,6 0,8 1
CO2 Loading (mol CO2 / mol DEEA)
Work in Progress for 30%
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and 35% DEEA solutions
CONCLUSIONS
Freezing point depression (FPD) are measured for H2O‐DEEAd O d l f O f diff land H2O‐MAPA and also for H2O‐DEEA‐MAPA for different molar
ratios of DEEA/MAPA [Data point = 76]
FPD are measured for H2O‐DEEA‐CO2 and H2O‐MAPA‐CO2systems at different CO2 loading [Data points = 57]systems at different CO2 loading [Data points 57]
Measured freezing point data illustrates that the MAPA‐watereasu ed ee g po t data ust ates t at t e ateinteraction is stronger than DEEA‐water interaction
The measured data can be used for modeling CO2 absorption/desorption system when aqueous blend of DEEA/MAPA is used
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FUTURE WORK
Measurement of FPD for 30% and 35% DEEA solutions withdifferent CO2 loadings
Measurement of freezing points For aqueous solutions of DEEA‐MAPA with different molar ratios loaded with CO2
Development of correlations for the freezing points as afunction of the solution compositionp
Thermodynamic modeling of H2O‐DEEA‐MAPA‐CO2 system usingy g 2 2 y gExtended UNIQUAC model
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THANK YOUTHANK YOU FOR
YOUR ATTENTION
QUESTIONS ?????
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