View
234
Download
0
Category
Preview:
Citation preview
7/26/2019 CO2 Capture Using DEA+MDEA
1/29
Rate-Based Model of theCO2Capture Process byDEA+MDEA AqueousSolution using AspenHYSYS
7/26/2019 CO2 Capture Using DEA+MDEA
2/29
Copyright (c) 2008-2011 by Aspen Technology, Inc. All rights reserved.
Aspen Properties, the aspen leaf logo and Plantelligence and Enterprise Optimization are trademarks or registeredtrademarks of Aspen Technology, Inc., Burlington, MA.
All other brand and product names are trademarks or registered trademarks of their respective companies.
This document is intended as a guide to using AspenTech's software. This documentation contains AspenTechproprietary and confidential information and may not be disclosed, used, or copied without the prior consent ofAspenTech or as set forth in the applicable license agreement. Users are solely responsible for the proper use ofthe software and the application of the results obtained.
Although AspenTech has tested the software and reviewed the documentation, the sole warranty for the softwaremay be found in the applicable license agreement between AspenTech and the user. ASPENTECH MAKES NOWARRANTY OR REPRESENTATION, EITHER EXPRESSED OR IMPLIED, WITH RESPECT TO THIS DOCUMENTATION,ITS QUALITY, PERFORMANCE, MERCHANTABILITY, OR FITNESS FOR A PARTICULAR PURPOSE.
Aspen Technology, Inc.200 Wheeler RoadBurlington, MA 01803-5501USAPhone: (1) (781) 221-6400Toll Free: (1) (888) 996-7100URL: http://www.aspentech.com
7/26/2019 CO2 Capture Using DEA+MDEA
3/29
Contents 1
Contents
Introduction ............................................................................................................ 2
1 Components ......................................................................................................... 3
2 Physical Properties ............................................................................................... 4
4 Reactions ........................................................................................................... 16
5 Simulation Approach .......................................................................................... 20
6 Simulation Results ............................................................................................. 24
References ............................................................................................................ 25
7/26/2019 CO2 Capture Using DEA+MDEA
4/29
2 Introduction
Introduction
The supplied HYSYS case CO2+H2S Capture Using DEA+MDEA.hscillustrates the use of rigorous rate-based distillation to accurately model CO2capture by a mixed DEA and MDEA aqueous solution from a gas mixture ofCO2, CH4, C2H6, C3H8, n-C4H10, i-C4H10, n-C5H12and N2. The actual fieldperformance data for an operating column from Weiland (2001)[1]were usedto specify feed conditions and specifications for the absorber.
Key features of this rigorous simulation include electrolyte thermodynamicsand solution chemistry, reaction kinetics for the liquid phase reactions,rigorous transport property modeling, rate-based multi-stage simulation withAspen Rate-Based Distillation which incorporates heat and mass transfercorrelations accounting for columns specifics and hydraulics.
The model is meant to be used as a guide for modeling the CO2captureprocess with DEA+MDEA. It may be used as a starting point for moresophisticated models for process development, debottlenecking, plant andequipment design, among others.
7/26/2019 CO2 Capture Using DEA+MDEA
5/29
1 Components 3
1 Components
The following components represent the chemical species present in theprocess:
Table 1. Components Used in the Model
ID Type Name Formula
DEA Conventional DIETHANOLAMINE C4H11NO2-1
H2O Conventional WATER H2O
CO2 Conventional CARBON-DIOXIDE CO2
H2S Conventional HYDROGEN-SULFIDE H2S
H3O+ Conventional H3O+ H3O+
OH- Conventional OH- OH-
HCO3- Conventional HCO3- HCO3-
CO3-2 Conventional CO3-- CO3-2
DEAH+ Conventional DEA+ C4H12NO2+
DEACOO- Conventional DEACOO- C5H10NO4-HS- Conventional HS- HS-
S-2 Conventional S-- S-2
MDEA Conventional METHYL-DIETHANOLAMINE C5H13NO2
MDEAH+ Conventional MDEA+ C5H14NO2+
CH4 Conventional METHANE CH4
C2H6 Conventional ETHANE C2H6
C3H8 Conventional PROPANE C3H8
C4H10-01 Conventional N-BUTANE C4H10-1
C4H10-02 Conventional ISOBUTANE C4H10-2
C5H12-01 Conventional N-PENTANE C5H12-1N2 Conventional NITROGEN N2
O2 Conventional OXYGEN O2
CO Conventional CARBON-MONOXIDE CO
H2 Conventional HYDROGEN H2
7/26/2019 CO2 Capture Using DEA+MDEA
6/29
4 2 Physical Properties
2 Physical Properties
The physical properties for the simulation were configured using AspenProperties. A pre-configured Aspen Properties file (DEA+MDEAProperties.aprbkp) has been provided. The details of the physical propertiesconfiguration are provided below.
The electrolyte NRTL method is used for liquid and RK equation of state isused for the vapor. The NRTL parameters were regressed against
CO2solubility data in aqueous DEA solutions from Maddox et al. (1987,1989)[6,7]for the sub-system CO2-DEA-H2O
CO2solubility data in aqueous MDEA solutions from Jou et al. (1982,1993)[8,9,10], Kuranov et al. (1996)[11]and Kamps et al. (2001)[12]for thesub-system CO2-MDEA-H2O
CO2solubility data in aqueous DEA+MDEA solutions from Benamor andAroua (2005)[13]for the mixed amine system CO2-DEA-MDEA-H2O systemon the basis of the NRTL parameters for the sub-systems CO2-DEA-H2Oand CO2-MDEA-H2O
H2S solubility data in aqueous DEA solutions from Barreau et al. (2006)[14]
and from Lawson and Garst (1976)[15]for the sub-system H2S-DEA-H2O H2S solubility data in aqueous MDEA solutions from Kuranov et al.
(1996)[11]and Kamps et al. (2001)[12]for the sub-system H2S-MDEA-H2O
CO2, CH4, C2H6, C3H8, n-C4H10, i-C4H10, n-C5H12, N2, O2, CO and H2areselected as Henry-components to which Henrys law is applied.The Henrysconstants are retrieved from Aspen Properties databanks for thesecomponents with water, except for those for n-C5H12with H2O, which aretaken from NIST web database. For solvents MEA and MDEA, the Henrysconstants are obtained as follows:
For CO2with DEA, regressed from CO2 solubility data[6,7]in aqueous DEA
solutions
For CO2with MDEA, regressed from CO2solubility data[8-12]in aqueous
MDEA solutions
For H2S with DEA, regressed from H2Ssolubility data[14,15]in aqueous DEA
solutions
For H2S with MDEA, regressed from H2S solubility data[11,12]in aqueous
MDEA solutions
However, we do not have any information to identify the Henrys constantsfor the hydrocarbon species with DEA or MDEA. In the reactions calculations,
7/26/2019 CO2 Capture Using DEA+MDEA
7/29
2 Physical Properties 5
the activity coefficient basis for the Henrys components (solutes) is chosen tobe Aqueous. Therefore, in calculating the unsymmetric activity coefficients(GAMUS) of the solutes, the infinite dilution activity coefficients are calculatedbased on infinite-dilution condition in pure water, instead of in mixedsolvents.
The liquid molar volume model and transport property models have beenvalidated for the sub-systems CO2-DEA-H2O and CO2-MDEA-H2O and modelparameters are regressed from literature experimental data[16-26]for thesetwo sub-systems. However, no data are found for the mixed amine systemloaded with CO2. And we did not check these properties of the DEA and/orMDEA systems loaded with H2S. Specifications of the transport propertymodels include:
For liquid molar volume, the Clarke model, called VAQCLK in AspenProperties, is used with option code 1 to use the quadratic mixing rule forsolvents.The interaction parameter VLQKIJ for the quadratic mixing rule betweenDEA and H2O is regressed against experimental DEA-H2O density datafrom Maham et al. (1994)[16], and VLQKIJ between MDEA and H2O isregressed against experimental MDEA-H2O density data from Bernal-Garcia et al. (2003)[17].
The Clarke model parameter VLCLK/1 is also regressed for mainelectrolytes (DEAH+, HCO
3), (DEAH+, DEACOO ) and (DEAH+, CO 2
3
)
against experimental density data of the CO2-DEA-H2O system fromWeiland (1998)[18]and for (MDEAH+, HCO
3) and (MDEAH+, CO 2
3) against
experimental density data of the CO2-MDEA-H2O system from Weiland(1998)[18]
For liquid viscosity, the Jones-Dole electrolyte correction model, calledMUL2JONS in Aspen Properties, is used with the mass fraction basedASPEN liquid mixture viscosity model for the solvent. There are threemodels for electrolyte correction and the DEA+MDEA model always usesthe Jones-Dole correction model. The three option codes for MUL2JONSare set to 1 (mixture viscosity weighted by mass fraction), 1 (always useJones and Dole equation when the parameters are available), and 2(ASPEN liquid mixture viscosity model), respectively.
The interaction parameters between DEA and H2O in the ASPEN liquidmixture viscosity model, MUKIJ and MULIJ, are regressed againstexperimental DEA-H2O viscosity data from Oyevaar(1989)
[19], Rinker et al.(1994)[20], Hsu and Li (1997)[21], Weiland (1998)[18], and Mandal et al.(2003)[22]. MUKIJ and MULIJ between MDEA and H2O are regressedagainst experimental viscosity data of the MDEA-H2O system from Teng etal. (1994)[23].
The Jones-Dole model parameters, IONMUB, for DEAH+and DEACOO-areregressed against CO2-DEA-H2O viscosity data from Weiland (1998)
[18];for MDEAH+, is regressed against CO2-MDEA-H2O viscosity data fromWeiland (1998)[18]; for CO 2
3
, is regressed against K2CO3-H2O viscosity
data from Pac et al. (1984)[24]; and for HCO3-, is regressed against KHCO3-
H2O viscosity data from Palaty (1992)[25].
For liquid surface tension, the Onsager-Samaras model, called SIG2ONSGin Aspen Properties, is used with its option codes being -9 (exponent in
7/26/2019 CO2 Capture Using DEA+MDEA
8/29
6 2 Physical Properties
mixing rule) and 1 (electrolyte system), respectively. Predictions for thesub-systems CO2-DEA-H2O and CO2-MDEA-H2O are within the range of theexperimental data from Weiland (1996)[26].
For thermal conductivity, the Riedel electrolyte correction model, calledKL2RDL in Aspen Properties, is used.
For binary diffusivity, the Nernst-Hartley model, called DL0NST in AspenPlus, is used with option code of 1 (mixture viscosity weighted by massfraction).
In addition to the updates with the above transport properties, heat capacityat infinite dilution (CPAQ0) for MDEAH+, DEAH+and DEACOO-are adjusted tofit to heat capacity data from Weiland (1996)[26].
The aqueous phase heat of formation at infinite dilution and 25C (DHAQFM)for DEAH+and DEACOO-are adjusted to fit to the literature heat of solutiondata from Carson et al. (2000)[27]of the sub-system CO2-DEA-H2O. ForMDEAH+, the databank value for DHAQFM is -5.0471 x108J/kmol, whichresults in heat of solution predictions for the sub-system CO2-MDEA-H2O asshown in Figure 6b-1 together with the data from Carson et al. (2000)[27].
However, to match the temperature profile data of an plant absorber for CO2capture by aqueous MDEA solutions[28], its found that a value of -5.0x108J/kmol for DHAQFM of MDEAH+ is better. This value is used in thecurrent simulation and results in heat of solution predictions as shown inFigure 6b-2.
The estimation results of various transport and thermal properties aresummarized in Figures 1-8:
900
950
1000
1050
1100
1150
1200
0 0.1 0.2 0.3 0.4 0.5
CO2 Loading, mol/mol
Dens
ity,
kg
/m3
EXP DEA 10w t%EXP DEA 20w t%EXP DEA 30w t%EXP DEA 40w t%EST DEA 10w t%
EST DEA 20w t%EST DEA 30w t%EST DEA 40w t%
Figure 1a. Liquid Density of DEA-CO2-H2O at 298.15K, experimental datafrom Weiland (1998)[18]
7/26/2019 CO2 Capture Using DEA+MDEA
9/29
2 Physical Properties 7
900
950
1000
1050
1100
1150
1200
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
CO2 Loading, mol/mol
Dens
ity,
kg
/m3
EXP MDEA 30w t%
EXP MDEA 40w t%
EXP MDEA 50w t%
EXP MDEA 60w t%
EST MDEA 30w t%
EST MDEA 40w t%
EST MDEA 50w t%
EST MDEA 60w t%
Figure 1b. Liquid Density of MDEA-CO2-H2O at 298.15K, experimental datafrom Weiland (1998)[18]
0.1
1
10
0 0.1 0.2 0.3 0.4 0.5
CO2 Loading, mol/mol
Viscosity,mPaS
EXP DEA 20w t%
EXP DEA 30w t%
EXP DEA 40w t%
EST DEA 20w t%
EST DEA 30w t%
EST DEA 40w t%
Figure 2a. Liquid Viscosity of DEA-CO2-H2O at 298.15K, experimental datafrom Weiland (1998)[18]
7/26/2019 CO2 Capture Using DEA+MDEA
10/29
8 2 Physical Properties
1.00
10.00
100.00
1000.00
0 0.1 0.2 0.3 0.4 0.5
CO2 Loading
Log
(Viscos
ity,
mPaS
)
EXP MDEA 30w t%EST MDEA 30w t%EXP MDEA 40w t%EST MDEA 40w t%EXP MDEA 50w t%EST MDEA 50w t%EXP MDEA 60w t%EST MDEA 60w t%
Figure 2b. Liquid Viscosity of MDEA-CO2-H2O at 298.15K, experimental datafrom Weiland (1998)[18]
0
10
20
30
40
50
60
70
80
90
100
0.00 0.10 0.20 0.30 0.40 0.50
CO2 Loading, mol/mol
Surface
Tens
ion,
mN/m
EXP DEA 10w t%EST DEA 10w t%EXP DEA 20w t%EST DEA 20w t%EXP DEA 30w t%EST DEA 30w t%EXP DEA 40w t%EST DEA 40w t%
Figure 3a. Surface tension of DEA-CO2-H2O at 298.15K, experimental datafrom Weiland (1996)[26]
7/26/2019 CO2 Capture Using DEA+MDEA
11/29
2 Physical Properties 9
0.03
0.04
0.05
0.06
0.07
0.08
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
CO2 Loading
Surface
Tens
ion,N
/m
EXP MDEA 30w t%EST MDEA 30w t%EXP MDEA 40w t%EST MDEA 40w t%EXP MDEA 50w t%EST MDEA 50w t%EXP MDEA 60w t%
EST MDEA 60w t%
Figure 3b. Surface tension of MDEA-CO2-H2O at 298.15K, experimental datafrom Weiland (1996)[26]
0
0.1
0.2
0.3
0.4
0.5
0.6
0 0.1 0.2 0.3 0.4 0.5 0.6
CO2 Loading, mol/mol
ThermalConductivity,
Wat
t/m-K
DEA 10w t%
DEA 20w t%
DEA 30w t%
DEA 40w t%
Figure 4a. Liquid Thermal Conductivity of DEA-CO2-H2O at 298.15K
7/26/2019 CO2 Capture Using DEA+MDEA
12/29
10 2 Physical Properties
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0 0.1 0.2 0.3 0.4 0.5
CO2 Loading, mol/mol
Therma
lCon
duc
tiv
ity,
Wa
tt/mK
EST MDEA 30w t%
EST MDEA 40w t%
EST MDEA 40w t%
EST MDEA 60w t%
Figure 4b. Liquid Thermal Conductivity of MDEA-CO2-H2O at 298.15K
Figure 5a. Liquid Heat Capacity of DEA-CO2-H2O at 298.15K, experimentaldata from Weiland (1996)[26]
7/26/2019 CO2 Capture Using DEA+MDEA
13/29
2 Physical Properties 11
0
20
40
60
80
100
120
140
160
0 0.1 0.2 0.3 0.4 0.5
CO2 Loading
Hea
tCapac
ity,
J/mol-
K
EXP MDEA 30w t%
EXP MDEA 40w t%
EXP MDEA 50w t%
EXP MDEA 60w t%
EST MDEA 30w t%
EST MDEA 40w t%
EST MDEA 50w t%
EST MDEA 60w t%
Figure 5b. Liquid Heat Capacity of MDEA-CO2-H2O at 298.15K, experimentaldata from Weiland (1996)[26]
Figure 6a. Heat of Solution of DEA-CO2-H2O at 298.15K, experimental datafrom Carson et al. (2000)[27]
7/26/2019 CO2 Capture Using DEA+MDEA
14/29
12 2 Physical Properties
Figure 6b-1. Heat of Solution of CO2in MDEA-H2O using ASPEN databankDHAQFM(MDEAH+) value (-5.0471E8J/kmol), experimental data from Carsonet al. (2000)[27]
Figure 6b-2. Heat of Solution of CO2in MDEA-H2O using DHAQFM(MDEAH+)=-
5.0E8J/kmol, experimental data from Carson et al. (2000)[27]
7/26/2019 CO2 Capture Using DEA+MDEA
15/29
2 Physical Properties 13
Figure 7a. CO2partial pressure of DEA-CO2-H2O (DEA mass fraction = 0.20),experimental data from Maddox et al. (1989)[7]
1
10
100
1000
10000
0.1 1 10
CO2 Loading
CO2Pressure,
KPa
EXP 310.9K
EST 310.9K
EXP 338.7K
EST 338.7K
EXP 388.7K
EST 388.7K
Figure 7b. CO2Partial Pressure of MDEA-CO2-H2O (MDEA mass fraction =0.20), experimental data from Maddox et al. (1987)[6]
7/26/2019 CO2 Capture Using DEA+MDEA
16/29
14 2 Physical Properties
0.1
1
10
100
1000
0.01 0.1 1
CO2 Loading
CO2Pressure,k
Pa
EXP 303K
EST 303K
EXP 313K
EST 313K
EXP 323K
EST 323K
Figure 7c. CO2Partial Pressure of DEA-MDEA-CO2-H2O (MDEA 1m and DEA1m), experimental data from Benamor and Aroua (2005)[13]
0.001
0.01
0.1
1
10
100
1000
10000
100000
0.001 0.01 0.1 1 10
H2S Loading
H2
SPressure,mm
Hg
EXP 100F
EST 100F
EXP 150F
EST 150F
EXP 200F
EST 200F
EXP 250F
EST 250F
Figure 8a. H2S partial pressure of DEA-H2S-H2O (DEA mass fraction = 0.25),experimental data from Lawson and Garst (1976)[15].
7/26/2019 CO2 Capture Using DEA+MDEA
17/29
2 Physical Properties 15
0.1
1
10
1 10
m_H2S, mol/kg
H2SPressure,M
Pa
EXP 313.15KEST 313.15KEXP 333.15KEST 333.15KEXP 373.15KEST 373.15KEXP 393.15KEST 393.15KEXP 413.15KEST 413.15K
Figure 8b. H2S Partial Pressure of MDEA-H2S-H2O (MDEA molality = 4),experimental data from Kuranov et al. (1996)[11]
7/26/2019 CO2 Capture Using DEA+MDEA
18/29
16 4 Reactions
4 Reactions
DEA is a secondary ethanolamine, as shown in Figure 9. It can associate withH+to form an ion DEAH+, and can also react with CO2to form a carbamateion DEACOO-.
Figure 9. DEA Molecular Structure
MDEA is a tertiary ethanolamine, as shown below in Figure 10. It canassociate with H+to form MDEAH+but can not react with CO2to producecarbamate as is the case for primary or secondary ethanolamines.
Figure 10. MDEA Molecular Structure
The electrolyte solution chemistry has been modeled in Aspen Properties (seeDEA+MDEA Properties.aprbkp) using the CHEMISTRY model DEAMDEA.Chemical equilibrium is assumed with all the ionic reactions in the CHEMISTRYDEAMDEA. Since the kinetics of CO2 absorption play an important role indetermining the extent of CO2 capture in the absorber, the assumption ofchemical equilibrium made in the Chemistry model is insufficient. A ReactionSet called RDEAMDEA has been created in HYSYS to accurately model thekinetics. In RDEAMDEA, all reactions are assumed to be in chemicalequilibrium except those of CO2with OH
-, CO2with DEA and CO2with MDEA.
A. Chemistry : DEAMDEA (Configured in Aspen Properties)
1 Equilibrium OHOHO2H 32
7/26/2019 CO2 Capture Using DEA+MDEA
19/29
4 Reactions 17
2 Equilibrium 3322 HCOOHO2HCO
3 Equilibrium 23323 COOHOHHCO
4 Equilibrium OHDEAOHDEAH 32
5 Equilibrium
32 HCODEAOHDEACOO 6 Equilibrium OHHSSHOH 322
7 Equilibrium OHSHSOH 32
2
8 Equilibrium OHMDEAOHMDEAH 32
B. Reaction ID: RDEAMDEA (Configured in Aspen HYSYS)
R1 Equilibrium OHDEAOHDEAH 32
R2 Equilibrium OHOHO2H 32
R3 Equilibrium OHCOOHHCO 32323
R4 Equilibrium OHMDEAOHMDEAH 32
R5 Equilibrium OHHSSHOH 322
R6 Equilibrium OHSHSOH 32
2
R7 Kinetic 32 HCOOHCO
R8 Kinetic OHCOHCO 23
R9 Kinetic OHDEACOOOHCODEA 3-
22
R10 Kinetic 223- COOHDEAOHDEACOO
R11 Kinetic -322 HCOMDEAHOHCOMDEA
R12 Kinetic OHCOMDEAHCOMDEAH 22-
3
The equilibrium expressions for the reactions are taken from the work ofAustgen et al. (1988, 1991)[29,30]and Jou et al. (1982, 1993)[8,9, 10]. Thepower law expressions (T0not specified) are used for the rate-controlledreactions (reactions R7-R12 in RDEAMDEA):
N
i
a
i
n iC)RT
E(kTr
1
exp (1)
Where:
r= Rate of reaction;
k= Pre-exponential factor;
T= Absolute temperature;
n= Temperature exponent;
7/26/2019 CO2 Capture Using DEA+MDEA
20/29
18 4 Reactions
E= Activation energy;
R= Universal gas constant;
N= Number of components in the reaction;
Ci= Concentration of component i;
ai= The stoichiometric coefficient of component iin the reaction equation.In equation (1), the concentration basis is Molarity, the factor n is zero, k and Eare given in Table 2.
Zhang (2002)[31]assumed that free DEA can transfer CO2to MDEA andregenerate by itself simultaneously:
(A)22 CODEACODEA
(B) DEACOMDEAMDEACODEA 22
(C) -322 HCOMDEAHOHCOMDEA
We combine these three reactions and obtain the following reaction:(D) -
322 HCOMDEAHOHCOMDEA
Reaction (D) is used to represent the chemical equilibrium between MDEA andCO2, and the following rate expression is used to represent the catalytic effectof DEA on reaction (D):
2exp CODEAMDEA
n CC)CRT
E(kTr (2)
To implement the catalytic effect of DEA on reaction (D), we set thestoichiometric coefficient of DEA to 0 and the concentration exponent of DEAto 1 when we edit reactions R11 and R12 (Figure 11).
Figure 11a. Specifications of Reaction 11
7/26/2019 CO2 Capture Using DEA+MDEA
21/29
4 Reactions 19
Figure 11b. Specifications of Reaction 12
The kinetic parameters for reactions R7, R9 and R11 in Table 2 are derivedfrom the work of Rinker et al. (1996)[3],Pinsent et al. (1956)[4], andRamachandran et al. (2006)[5]. The kinetic parameters for the correspondingreversible reactions R8, R10 and R12 are calculated by using the kineticparameters and the equilibrium constants of the forward reactions R7, R9 andR11.
Table 2. Parameters k and Ein Equation (1)
Reaction k E, cal/mol
R7 4.32e+13 13249
R8 2.38e+17 29451
R9 6.48e+6 5072
R10 1.34e+17 11497
R11 3.12e+8 7432
R12 1.26e+12 15334
7/26/2019 CO2 Capture Using DEA+MDEA
22/29
20 5 Simulation Approach
5 Simulation Approach
The HYSYS flowsheet used to model the removal of CO2 using DEA andMDEA is shown below:
Figure 12. Rate-Based DEA+MDEA Simulation Flowsheet in Aspen HYSYS
The actual field performance data for an operating column from Weiland(2001)[1]were used to specify feed conditions and specifications for theabsorber.
7/26/2019 CO2 Capture Using DEA+MDEA
23/29
5 Simulation Approach 21
Unit Operations- Major unit operations used in this flowsheet are describedin Table 3
Table 3. HYSYS Unit Operation Blocks Used in the Rate-Based DEA+MDEA Model
Unit Operation HYSYS Block Comments / Specifications
ABSORB
ER
RateBased Column Purpose: Models amine/sour gas contactor/absorber
1. Calculation type: Rate-Based
2. 22 Stages
3. Top Pressure: 900psig
4. Reaction condition factor: 0.5
5. Film discretization ratio: 2
6. Heater Cooler: Heat loss is ignored for the absorber
7. Reaction: Reaction ID is RDEAMDEA for all stages
8. Tray Type: Sieve
9. Tray Diameter: 5ft
10 Sieve hole area to active area fraction: 0.0811. Mass transfer coefficient method: Chan and fair (1984)
12. Interfacial area method: Zuiderweg (1982)
13. Interfacial area factor: 1
14. Heat transfer coefficient method: Chilton and Colburn
15. Holdup correlation: Bennett et al. (1983)
16. Film resistance: Discrxn for liquid film; Film for vaporfilm
17. Additional discretization points for liquid film: 5
18. Flow model: Mixed
19. Estimates: provide temperature estimates for all stages.
These estimates are intended to aid convergenceNote:
1. The ABSORBER RateBased Column uses the Truesimulation approach because the reaction rateexpression requires the composition of individual ions.
2. A True to Apparent transition is used to compute theapparent composition of the RICH AMINE stream toensure consistent calculations in the downstream blocks
VLV-100 Valve Purpose : Reduces RICH AMINE pressure to 90 psi
FLASH TK Separator Flash Tank
L/R HX Heat Exchanger Purpose: Lean/Rich heat exchanger
Tube-side outlet temperature:200F
REGENERATOR RateBased Column Purpose: Models the stripper/regenerator
1. Calculation type: Equilibrium
2. 20 Stages including Condenser and Reboiler
3. Top Pressure: 21 psi
7/26/2019 CO2 Capture Using DEA+MDEA
24/29
22 5 Simulation Approach
Unit Operation HYSYS Block Comments / Specifications
4. Distillate Mass Flow Rate : 5000 lb/hr
5. Mass Reflux Ratio : 1
Note:
1. The REGENERATOR RateBased Column uses the True
simulation approach because the reaction rateexpression requires the composition of individual ions.
2. A True to Apparent transition is used to compute theapparent composition of the REGEN BTTMSstream toensure consistent calculations in the downstream blocks
TANK Mixer Purpose : Models tank holding DEA+MDEA solution
Computes MAKEUP H2O flow from specified recirculation rate
COOLER Cooler Purpose : Cools lean amine solution to 118F
P-100 Pump Purpose : Raises pressure of lean amine to 900 psig
7/26/2019 CO2 Capture Using DEA+MDEA
25/29
5 Simulation Approach 23
Streams- Feeds to the absorber are SOUR GAS containing N2, CH4, C2H6,C3H8, n-C4H10, i-C4H10, n-C5H12and CO2and AMINE TO CONTACTORcontaining aqueous DEA and MDEA solution loaded with some CO2. Feedconditions are summarized in Table 4.
Table 4. Feed specificationsStream ID SOUR GAS AMINE TO CONTACTOR
Temperature: F 80 118
Pressure: psig 910 910
Total flow 106351.7 lb/hr 7.548e4 lb/hr
Composition Mole-Frac Mass-Frac
H2O 0 0.564
CO2 0.0199 0.006
DEA 0 0.15
MDEA 0 0.28
CH4 0.8544 0C2H6 0.066 0
C3H8 0.0236 0
C4H10-01 0.0077 0
C4H10-02 0.0089 0
C5H12-01 0.017 0
N2 0.0019 0
7/26/2019 CO2 Capture Using DEA+MDEA
26/29
24 6 Simulation Results
6 Simulation Results
The simulation was performed using Aspen HYSYS V7.3. Key simulationresults are presented in Table 5.
Table 5. Key Simulation Results
CO2mole fraction in SWEET GAS 1082 ppmLoading of Rich Amine, Moles Acid Gas/Moles Amine 0.3902
Loading of Lean Amine, Moles Acid Gas/Moles Amine 0.036
7/26/2019 CO2 Capture Using DEA+MDEA
27/29
References 25
References
[1] R.H. Weiland, J.C. Dingman,Eliminating Guess Work,HydrocarbonEngineering, 2001
[2] Aspen Technology Inc., 2007
[3] E.B. Rinker, S.S. Ashour, O.C. Sandall,Kinetics and Modeling of CarbonDioxide Absorption into Aqueous Solutions of Diethanolamine, Ind. Eng.Chem. Res., 35, 1107-1114 (1996)
[4] B.R. Pinsent, L. Pearson, F.J.W. Roughton, The Kinetics of Combination ofCarbon Dioxide with Hydroxide Ions, Trans. Faraday Soc., 52, 1512-1520(1956)
[5] N. Ramachandran, A. Aboudheir, R. Idem, P. Tontiwachwuthikul,Kineticsof the Absorption of CO2into Mixed Aqueous Loaded Solutions ofMonoethanolamine and Methyldiethanolamine, Ind. Eng. Chem. Res., 45,2608-2616(2006)
[6] R.N. Maddox, A.H. Bhairl, J.R. Diers, P.A. Thomas, Equilibrium Solubilityof Carbon Dioxide or Hydrogen Sulfide in Aqueous Solutions ofMonoethanolamine, Diglycolamine, Diethanolamine andMethyldiethanolamine, GPA Research Report, NO. 104, 1987
[7] R.N. Maddox, E.M. Elizondo, Equilibrium Solubility of Carbon Dioxide orHydrogen Sulfide in Aqueous Solutions of Diethanolamine at Low PartialPressures, GPA Research Report, NO. 124, 1989
[8] F.-Y. Jou, A.E. Mather, F.D. Otto,Solubility of Hydrogen Sulfide andCarbon Dioxide in Aqueous Methyldiethanolamine Solutions,Ind. Eng. Chem.Proc. Des. Dev., 21, 539-544 (1982)
[9] F.-Y. Jou, J.J. Carroll, A.E. Mather, F.D. Otto,Solubility of Mixtures ofHydrogen Sulfide And Carbon Dioxide in Aqueous N-MethyldiethanolamineSolutions,J. Chem. Eng. Data, 38, 75-77 (1993)
[10] F.-Y. Jou, J.J. Carroll, A.E. Mather, F.D. Otto,The Solubility of CarbonDioxide and Hydrogen Sulfide in a 35 wt% Aqueous Solution ofMethyldiethanolamine,Can. J. Chem. Eng., 71, 264-268 (1993)
[11] G. Kuranov, B. Rumpf, N.A. Smirnova, G. Maurer, "Solubility of SingleGases Carbon Dioxide and Hydrogen Sulfide in Aqueous Solutions of N-Methyldiethanolamine in the Temperature Range 313-413 K at Pressures upto 5 MPa", Ind. Eng. Chem. Res., 35, 1959-1966 (1996)
7/26/2019 CO2 Capture Using DEA+MDEA
28/29
26 References
[12] . P.-S. Kamps, A. Balaban, M. Jdecke, G. Kuranov, N.A. Smirnova, G.Maurer, "Solubility of Single Gases Carbon Dioxide and Hydrogen Sulfide inAqueous Solutions of N-Methyldiethanolamine at Temperatures from 313 to393 K and Pressures up to 7.6 MPa: New Experimental Data and ModelExtension", Ind. Eng. Chem. Res., 40, 696-706 (2001)
[13] A. Benamor, M.K. Aroua, "Modeling of CO2 solubility and carbamateconcentration in DEA, MDEA and their mixtures using the DeshmukhMathermodel", Fluid Phase Equilibria, 231, 150162 (2005)
[14] A. Barreau, E. Blanchon le Bouhelec, K.N. Habchi Tounsi, P. Mougin, andF. Lecomte, "Absorption of H2S and CO2 in Alkanolamine Aqueous Solution:Experimental Data and Modelling with the Electrolyte-NRTL Model", Oil & GasScience and Technology Rev. IFP, 61, 3, 345-361(2006)
[15] J.D. Lawson and A.W. Garst, "Gas Sweetening Data: EquilibriumSolubility of Hydrogen Sulfide and Carbon Dioxide in AqueousMonoethanolamine and Aqueous Diethanolamine Solutions", J. Chem. Eng.Data, 21, 20-30(1976)
[16] Y. Maham, T.-T. Teng, L.G. Hepler, A.E. Mather,Densities, excess molarvolumes, and partial molar volumes for binary mixtures of water withmonoethanolamine, diethanolamine, and triethanolamine from 25 to 80C, J.Solution Chem., 23, 2, 195-205(1994)
[17] J.M. Bernal-Garcia, M. Romas-Estrada, G.A. Iglesias-Silva,Densitiesand Excess Molar Volumes of Aqueous Solutions of N-Methyldiethanolamine(MDEA) at Temperatures from (283.15 to 363.15)K, J.Chem. Eng. Data, 48, 1442-1445 (2003)
[18] R.H. Weiland, J.C. Dingman, D.B. Cronin, G.J. Browning G.J.,Densityand viscosity of some partially carbonated aqueous alkanolamine solutionsand their blends, J. Chem. Eng. Data, Vol. 43, 378-382(1998)
[19] M.H. Oyevaar, R.W.J. Morsinkhof, K.R. Westerterp,Density, Viscosity,
Solubility, and Diffusivity of Diethanolamine in Aqueous Ethlyene Glycol at298K, J. Chem. Eng. Data., Vol. 34, Issue. 1, 77-82(1989)
[20] E.B. Rinker, D.W. Oleschager, A.T. Colussi, K.R. Henry, O.C. Sandall,Viscosity, Density, and Surface Tension of Binary Mixtures of Water and N-Methyldiethanolamine and Water and Diethanolamine and Tertiary Mixtures ofThese Amines with Water over the Temperature Range 20-100C, J. Chem.Eng. Data., 39, 392-395(1994)
[21] C.H. Hsu, M.H. Li,Viscosities of aqueous blended amines, J. Chem. Eng.Data., 42, 714-720(1997)
[22] B.P. Mandal, M. Kundu, S.S. Bandyopadhyay,Density and viscosity ofaqueous solutions of (N-methyldiethanolamine + monoethanolamine), (N-
methyldiethanolamine + diethanolamine), (2-amino-2-methyl-1-propanol +monoethanolamine), and (2-amino-2-methyl-1-propanol + diethanolamine),J. Chem. Eng. Data., 48, 703-707(2003)
[23] T.T. Teng, Y. Maham, L.G. Hepler, A.E. Mather, Viscosity of AqueousSolution of N-Methyldiethanolamine and of Diethanolamine, J. Chem. Eng.Data., 39, 290-293 (1994)
7/26/2019 CO2 Capture Using DEA+MDEA
29/29
[24] J.S. Pac, I.N. Maksimova, L.V. Glushenko, Viscosity of Alkali SaltSolutions and Comparative Calculation Method, J. Appl. Chem. USSR, 57,846 (1984)
[25] Z. Palaty,Viscosity of diluted aqueous K2CO3/KHCO3 solutions, Collect.Czech. Chem. Commun., 57, 1879(1992)
[26] R.H. Weiland,Physical Properties of MEA, DEA, MDEA and MDEA-BasedBlends Loaded with CO2, GPA Research Report, No. 152, 1996
[27] J.K. Carson, K.N. Marsh, A.E. Mather, Enthalpy of solution of carbondioxide in (water + monoethanolamine, or diethanolamine, or N-methyldiethanolamine) and (water + monoethanolamine + N-methyldiethanolamine) at T = 298.15 K, J. Chem. Thermodyn., 32, 1285-1296 (2000)
[28] R. Giesen., Mathematische Modellierung des MDEAAbsorptionsprozesses. PhD Diss., the Rheinisch Westfli Technical Universityat Aachen, 2004
[29] D.M. Austgen, G.T. Rochelle, X. Peng, C.-C. Chen, A Model of Vapor-
Liquid Equilibria in the Aqueous Acid Gas-Alkanolamine System Using theElectrolyte-NRTL Equation, paper presented at the New Orleans AIChEmeeting, March 1988
[30] D.M. Austgen, G.T. Rochelle, C.-C. Chen, Model of Vapor-LiquidEquilibria for Aqueous Acid Gas-Alkanolamine Systems. 2. Representation ofH2S and CO2 Solubility in Aqueous MDEA and CO2 Solubility in AqueousMixtures of MDEA with MEA and DEA, Ind. Eng.Chem. Res., 30, 543-555(1991)
[31] X. Zhang, C.F. Zhang, Y. Liu,Kinetics of Absorption of CO2into AqueousSolution of MDEA Blended with DEA,Ind. Eng. Chem. Res., 41, 1135-1141(2002)
Recommended