E a 1 1 sat sat ln Py x P Py x P K H k Ae R E sat a Py x P 1 1 sat ln K1 R Py x P K H k Ae R 1 CO P H 1 1 abs ln K H H 1/ R Q C 1 1 CO P ln S K H K1 R 1 P H abs H P K1 R CP 1 K1 R 1/ R S Q P 1 E a E du q w a du q w du q w Q k Ae R k Ae R E du q w a E a Q sat S Py x P Q Q k Ae R k Ae R S sat S S Py x P G U S PV G U S PV CO P H dq du PdV dq du PdV G abs dq du PdV CO dq du PdV P H abs E a 1/ R E a G E i E a k Ae R N k Ae R i, P, N j i Q a 1/ R S k Ae R i k Ae R N An Innovative Approach in the i, P, N Q j i S CO H H C P H H CO H P abs C P C P H P P CP P 1/ R H abs P 1/ R H C P G U S PV G U S PV Q P G U S PV CP S G U S PV Development of H U PV H Physical P U PV Properties P H U PV H U PV S Q for H U PV H U PV PV nr H PV nr PV nr PV nr H PV nr C PV nr C P P P G G G G G Carbon Capture echnologies P G i Ni PV i,, nr N i i i Ni, P, N Ni i, P, N PV N j i P N,, j i nr i, P, Nj i P N j i j i i N 1 1 ln K H sat i, P, Nj i Py x P CO 1 1 P H ln CO P H K1 R du q w abs K H sat CO P H Py x P CO abs P H abs 1/ R K1 R 1 du q w 1/ R 1 abs 1/ R 1/ R sat Py x P 1 1 sat ln Py x P K H sat sat Py x P 1 1 Py x P ln K H E a CO P H K1 R CO K1 R k Ae 1 R 1 abs P H 1 1 ln K H 1/ R K1 R S Q abs 1 1 ln K H 1/ R 1 K1 R S Q H CP 1 P du q w du q w E du q w E a du q w a S Q S Q k Ae R S Q S Q k Ae R E a k Ae R sat G U S PV G U S PV Py x P By dq du PdV dq du PdV dq du PdV dq du PdV CO G G P H E a E a E a k Ae R k Ae R i E a Marcus abs Ni, P, Hilliard k Ae R i Nj i k Ae R N 1/ R i, P, Nj i H C H CO P CP P P H H S Q abs H CO C CP P P H P 1/ R abs P P 1/ R G U S PV G U S PV S Q G U S PV H G U S PV H U PV S Q CP he Dow Chemical Company P H U PV H U PV H U PV H U PV PV nr PV nr H CP PV nr G i PV nr H C PV nr P P Gary. Rochelle G G N G P G i, P, N i j i i Ni PV nr i i, P, N N N i i j i, P, N, P, N PV nr Ni j i CO sat j i, P, Nj i P H abs 1/ R ln K H 1 1 Py he x P University of exas at Austin CO du q w P ln K H 1 1 sat Py x P CO H abs P H abs
background carbon capture technologies his research addresses the solvent development of carbon capture technologies for use in coal fired power plants (CFPP) Post-combustion capture with aqueous alkanolamines is an attractive technology for CO removal in conventional CFPP ail end process Lower capital cost for existing power plants Easy to develop and demonstrate Mature capture technology (30 wt % MEA) Acid gas 70 years CH 4 combustion 30 years Coal in smaller plants 0 years
background carbon capture technologies he design of optimal processes and solvents Requires the development of a robust physical property model to describe the reactive separation Key modeling challenges: he design of process equipment he characterization of phase equilibrium and thermal effects Solvents considered Monoethanolamine (MEA) Increase in capacity, faster rates, robustness Piperazine (PZ) K CO 3 /PZ N-methyldiethanolamine (MDEA)
process - aqueous absorption Clean Gas 1% CO Cooler -4 mol H O/mol CO Absorber 40 60 o C 1 atm Stripper 100 10 o C 1- atm Flue Gas 10% CO Rich Solvent Lean Solvent Reboiler
approach for solvent development Mass ransfer Driving force Capacity Speciation Calorimetry C p CO P as f,ldg [amine] kinetics Volatility Amine P* H abs with solvent characterization through rigorous modeling
aspen plus 006.5 framework Enthalpy Hm R Gm / R G x x x x G * * * E m ww k k j ln j m k j P E ngm / R ln i n i ln P,, n i G R K i * m ln K i f C pm, H m P Phase Equilibrium Aqueous Chemistry G o o o o 0 0 0 1 o o m G H H CP CP d ln Ki d R R R R R 0 0 0
elecnrl property method Activity coefficient model in Aspen Plus 006.5 E E E E G PDH Born NRL G G G R R R R Electrolyte NRL model for the liquid phase Redlich-Kwong EoS for the vapor phase Reference state convention: Inf. Dil. Aqu. phase for molecular solutes (i.e. CO ) and ions Pure liquid for molecular solvents (i.e. H O and MEA)
elecnrl modeling approach Modeling the phase equilibrium and thermal effects hrough sequential non-linear regressions with multiple, independent data sets Adjusting temperature dependant binary interaction parameters ypically, two types of binary interaction parameters are used in aqueous mixtures: Molecule-Molecule Binary Parameters B mm, A C ln F Electrolyte-Molecule Pair Parameters m, ca D 98.15K C E ln 98.15 K
aqueous chemistry CO Solubility CO H abs Complex Mass ransfer with Chemical Reactions HO CO MEA Vapor Phase Amine Volatility HO CO H O H O OH 3 H O CO H O HCO 3 3 H O HCO H O CO 3 3 3 3 MEA H O MEAH H O MEA l Liquid Phase H O MEACOO MEA l HCO 3 NMR Speciation Specific Heat Capacity
international collaboration High Pres. CO Solubility (100 10 o C) Measured by Marcus Hilliard (NNU) Calorimeter (40 10 o C) Measured by Inna Kim (NNU) AM Pres. Reactor (30 70 o C) (multi-component vapor phase analysis reactor) Measured by Marcus Hilliard (U) Differential Scanning Calorimeter: Specific Heat Capacity & PZ Solubility Measured by Marcus Hilliard (U) NMR Speciation Measured by Steve Sorey and Jim Wallin (U) X-ray Diffraction H abs Crystallization Identification Measured by Vince Lynch (U)
sequential regression Number of System Sources Parameters AARD (%) H O 4 1.3 MEA 6.3 PZ 3.7 H O-MEA 10 6.6 H O-PZ 3 4 5.8 H O-MEA-PZ * 1 10 4.3 H O-MEA-N O 4 3 3.5 H O-K CO 3 -CO 6 3 3.9 H O-MEA-CO 8 35 4.8 H O-PZ-CO 3 4 35 10.6 H O-K CO 3 -PZ-CO 3 33 15.5 H O-MEA-PZ-CO 4 (6) 37.9
approach for solvent development Mass ransfer Driving force Capacity Speciation Calorimetry C p CO P as f,ldg [amine] kinetics Volatility Amine P* H abs with solvent characterization through rigorous modeling
CO Partial Pressure (kpa) CO Solubility in 7m MEA at 40 o C 10000 1000 100 Austgen (1989) - Aspen ech (008) 10 Freguia (00) 1 0.1 0.01 0.001 Jou et al. (1995) Hilliard (008) Lee et al. (1976) - corrected 0.0001 0 0.1 0. 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Loading (mol CO /mol MEA)
CO Partial Pressure (kpa) CO Solubility in 7m MEA at 60 o C 100000 10000 1000 Austgen (1989) - Aspen ech (008) 100 10 1 0.1 Differential Capacity Jou et al. (1995) Hilliard (008) Freguia (00) 0.01 Lee et al. (1976) - corrected 0.001 0 0.1 0. 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Loading (mol CO /mol MEA)
Differential Capacity (mol CO /kg-h O) Differential Capacity wrt P CO (0.01 1.0 kpa) at 60 o C 4 3.5 3 H O-MEA-CO.5 H O-MEA-PZ-CO 1.5 H O-K CO 3 -MEA-PZ-CO 1 0.5 H O-PZ-CO H O-MDEA-CO H O-K CO 3 -MEA-CO H O-K CO 3 -PZ-CO 0 0 4 6 8 10 1 14 16 18 0 otal Alkalinity (m)
approach for solvent development Mass ransfer Driving force Capacity Speciation Calorimetry C p CO P as f,ldg [amine] kinetics Volatility Amine P* H abs with solvent characterization through rigorous modeling
MEA Partial Pressure (kpa) MEA Volatility in 7 m MEA 1 0.1 0.01 Closed Pt: Hilliard (008) Solid Curves: Hilliard (008) Dashed Curves: Austgen (1989) - Aspen ech (008) 0.001 30 35 40 45 50 55 60 65 70 75 80 emperature ( o C)
MEA Partial Pressure (kpa) MEA Volatility in 7 m MEA at 40 and 60 o C 0.1 0.01 0.001 43 ppm v 60 o C 0.0001 40 o C 0.00001 Closed Pt: Hilliard (008) Solid Curves: Hilliard (008) Dashed Curves: Austgen (1989) - Aspen ech (008) 0 0.1 0. 0.3 0.4 0.5 0.6 0.7 Loading (mol CO /mol MEA)
H O Partial Pressure (kpa) H O Volatility in 7 m MEA at 40 and 60 o C 100 60 o C 10 40 o C 1 Closed Pt: Hilliard (008) Solid Curves: Hilliard (008) Dashed Curves: Austgen (1989) - Aspen ech (008) 0 0.1 0. 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Loading (mol CO /mol MEA)
approach for solvent development Mass ransfer Driving force Capacity Speciation Calorimetry C p CO P as f,ldg [amine] kinetics Volatility Amine P* H abs with solvent characterization through rigorous modeling
nmr speciation Phase equilibrium measurements rely on total [amine] and total [CO ] Equilibrium conditions apply to the activities rather than concentrations NMR provides concentrations of: MEA/MEAH + = MEA + MEAH + MEACOO -1 C 13 CO HCO 3-1 /CO 3 - = HCO 3-1 + CO 3 - Reference: 1 wt % Dioxane Regression based on user subroutine
C 13 NMR Speciation for 7 m MEA at 40 o C 10 MEA + MEAH + mole/kg-h O of Species i 1 0.1 0.01 0.001 MEACOO -1 MEA HCO -1 3 + CO - 3 Solid Pt: Poplsteinovo (004) Open Pt: Hilliard (008) Solid Curves: Hilliard (008) Dashed Curves: Austgen (1989) - Aspen ech (008) 0 0.1 0. 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Loading (mol CO /mol MEA)
Mole Fraction of Species i CO Speciation for 7 m MEA at 40 o C 1 0.1 Solid Curves: Hilliard (008) Dashed Curves: Austgen (1989) - Aspen ech (008) 0.01 0.001 HCO 3-1 0.0001 0.00001 CO 3-0.000001 0.0000001 CO 0.00000001 0 0.1 0. 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Loading (mol CO /mol MEA)
approach for solvent development Mass ransfer Driving force Capacity Speciation Calorimetry C p CO P as f,ldg [amine] kinetics Volatility Amine P* H abs with solvent characterization through rigorous modeling
enthalpy of co absorption Characterized by the heat of CO dissolution and the reaction between CO and the amine he magnitude of the H abs : determining the gas treating thermal effects Heat required for regeneration emperature dependence of P CO Can be measured directly or estimated from CO solubility H ln R 1/ Px, i Regression based on user subroutine abs f i
Differential -H CO (kj/mol-co ) Enthalpy of CO Absorption in 7 m MEA at 40 and 10 o C 140 10 10 o C 100 80 40 o C 60 40 0 0 Solid Pt: Kim and Svendsen (007) Solid Curves: Hilliard (008) Dashed Curves: Austgen (1989) - Aspen ech (008) 0 0.1 0. 0.3 0.4 0.5 0.6 0.7 Loading (mol CO /mol MEA)
enthalpy of co absorption Kim (009) determined the H abs based on equilibrium constants n k i Habs i n 1 O coz H r is evaluated through H i H R i ln K i P emperature dependant K i ln f K i Apply this method to H O-MDEA-CO
Integral - H CO (kj/mol-co ) Enthalpy of CO Absorption in 40 wt% MDEA at 60 and 115 o C 100 80 115 o C 60 60 o C 40 0 0 Solid Pt: Merkley et al. (1986) Solid Curves: his work Dashed Curves: Aspen ech (008) 0 0.1 0. 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Loading (mol CO /mol MDEA)
differences By implementing temperature dependant K i Process simulations converge faster Greater predictive capacity and robustness wrt concentrated solvents Allows a simplified yet accurate treatment of chemical reaction equilibrium Both approaches provide a rigorous characterization of the electrolyte thermodynamics and solution chemistry
approach for solvent development Mass ransfer Driving force Capacity Speciation Calorimetry C p CO P as f,ldg [amine] kinetics Volatility Amine P* H abs with solvent characterization through rigorous modeling
Cp (kj/kg-k) Specific Heat Capacity for loaded 7 m MEA 4.3 H O 4.1 3.9 3.7 Loading (a) = 0.0 a = 0.139 3.5 3.3 a = 0.541 3.1.9 MEA.7 40 50 60 70 80 90 100 emperature ( o C)
summary In this work: he Aspen Plus provides a robust framework for modeling of reactive mixtures and can be used as a starting point for more complex process model development Developed a new VLE apparatus = P CO, P Amine, P HO Amine blends illustrate an enhanced capacity over MEA At typical lean absorber conditions: P MEA = 43 ppm v Improved the enthalpy of CO absorption predictions ln K f Implementing through i Allows a simplified yet accurate treatment of chemical reaction equilibrium Improved the specific heat capacity predictions By including multiple independent data sets, into a sequential non-linear regression methodology, allows for substantial improvements in a model s overall predictive ability
his concludes my presentation hank you for your attention.
Additional Information
PZ Partial Pressure (kpa) PZ Volatility in m PZ at 40 o C 0.1 Hilliard (005) 0.01 5 ppm v 0.001 0.0001 his work 0.00001 0 0.05 0.1 0.15 0. 0.5 0.3 0.35 0.4 0.45 0.5 Loading (mol CO / mol PZ)
Solubility emperature ( o C) SLE Results for Mixtures of H O-PZ using DSC 10 110 100 90 Liquid Solution 80 70 Bishnoi (00) 60 10 m PZ 50 40 30 his work 5 m PZ PZ (s) 0 0 m PZ 10 PZ 6H O (s) 0 0 0.1 0. 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Piperazine (weight fraction)
emperature ( o C) SLE Predictions for loaded PZ Solutions 50 10 m PZ Possible Operating Region 40 5 m PZ 4 m PZ 30 3 m PZ Liquid 0 m PZ 10 1 m PZ 0 PZ 6H O (s) 0 0.05 0.1 0.15 0. 0.5 0.3 0.35 0.4 0.45 0.5 Loading (mol CO / mol PZ)
unit cell of K PZ(COO) COO - complex SEM image PZ K Crystal Size: 0.43 x 0.33 x 0.08 mm
SLE Results for K + + PZ Solutions 55 50 KHCO 3 (s) emperature ( o C) 45 40 35 5 m K + + 3.6 m PZ K PZ(COO) (s) 30 5 K + /PZ Ratio 3 4 5 m K + +.5 m PZ 6 m K + + 1. m PZ 5 6 0.30 0.35 0.55 0.50 0.45 0.40 0.60 0.65 Loading (mol CO /mol K + + mol PZ)
K + (m) Systems Exhibiting SLE Behavior for K + + PZ Solutions 7 6 5 6 m K + + 1. m PZ Systems which may exhibit solid phase precipitation 5 m K + +.5 m PZ 5 m K + + 3.6 m PZ 4 3 1 0 0 0.5 1 1.5.5 3 3.5 4 4.5 5 PZ (m)