1

J, 2008 U

Solvent Development for CO2 Capture

Ugochukwu E. Aronu and Hallvard F. SvendsenNorwegian University of Science and Technology (NTNU)

Trondheim, NORWAY

2

Outline

• Research Plan Overview

• CO2 Capture Amine Solvent Review

• Structure – pKa Relationship

• VLE Experiment

• Summary

3

Research Plan Overview

Review of CO2 capture solvents-Properties of an ideal solvent-Suggested/Future amine solvents

Screening Tests- Amine systems will be screened for absorption capacity and absorption rate

VLE Experiments -VLE experiment on selected system-Thermodynamic model of VLE results

Kinetics Experiments- Rate determination- Kinetics model

Physicochemical Properties Determination-pKa, Solubility, Viscousity, Activity Coefficient, Density

Simulations-HSYS

4

Objective

Objective of this project is to develop solvent(s) that will be able to meet considerably the present and/or future requirements of an ideal solvent for carbon dioxde capture.

Some of the key requirements of the solvent(s) include:

High absorption capacity High absorption rate Low regeneration energy Chemically stable Non-corrosive Cheap Environmentally friendly

5

CO2 Capture Solvents Review

• Ideal Solvent Properties of Interest

Here we look at the desired properties of an ideal solvent and how such property is related to CO2 capture process

- Dissociation Constant (pKa) - Heat of reaction- Solubility - Molecular weight- Degradation - Corrosion- Foaming - Vapour Pressure- Reaction Kinetics - Cost- Toxicity/Environmental properties

• Solvent Collection

– Commercial Solvent– Single Solvent– Blended Solvent

6

Commercial Amine Processes & Solvents

Amine Process/Solvent Developer Solvent Composition

Cansolv® CO2 capture System (Absorbent DC 101TM)

Cansolv Technologies Inc. Tertiary amine and promoter mixture

Flour Daniel Econamine FGSM process

Dow Chemical and Union Carbide

30wt% MEA with inhibitor

Kansai-Mitsubishi proprietary Carbon Dioxide Recovery Process (KM-CDR) KS-1

Mitsubishi Heavy Industries (MHI) Ltd and Kansai Electric Power Co., Ltd

Hindered amine and promoter mixture

BASF activated methyldiethanolamine (aMDEA)

BASF MDEA mixture with accelerator, Piperazine

Kerr-McGee/ABB Lummus Crest Technology

Kerr-McGee 15-20wt% MEA without inhibitors

UCARSOLTM AP 800 Series Dow Chemical Company Accelerated MDEA (MDEA/Piperazine mixture)

ADIP-X Technology Shell Global Solution Accelerated MDEA (MDEA/Piperazine mixture)

Just CatchTM Aker Kvaerner

7Some Single Amine Solvents

Name CAS NO Name CAS NOMonoethanolamine 141435 2-Amino-2-Ethyl-1,3-Propanediol 1157082-Ethylaminoethanol 110736 N-(2-aminoethyl)-1,3-propanediamine 13531527Monomethylethanolamine 109831 1,8-p -menthanediamine 80524Methyldiethanolamine 105599 2-piperidineethanol 14848402-Butylaminoethanol 111751 2-amino-2-methylpropionic acid 62577N-Aminoethylethanolamine 111411 2-amino-2-methyl-1-propanol 124685Piperazine 110850 1-amino-1-cyclopentanecarboxylic acid 52528Ammonia 7664417 1-amino-1-cyclohexanecarboxylic acid 21121379Methylamine 74895 2-amino-2-phenylpropionic acid 565071Ethylamine 75047 Pipecolinic acid 535751Dimethylamine 124403 2-amino-2-hdroxymethyl-1,3-propanediol 77861Trimethylamine 75503 Tetraethylenepentamine 112572Piperidine 110894 Bis(3-(dimethylamino)propyl)amine 6711484Morpholine 110918 Quinuclidine 100765Pyrrolidine 123751 2-Piperidinemethanol 34333722,2,6,6-Tetramethyl-4-piperidinol 2403885 2-Ethoxyethanol 1108051-amino-2-propanol 78966 tertiarybutylaminoethanol 46207062-amino-2-methylpropanol 124685 Diethylmonoethanolamine 100378Diethanolamine 111422 2-methyl-3-hydroxy piperidine 916083288Diisopropanolamine 110974 3-amino-3-methyl-1-butanol 42514501N-n- butylethanolamine 36386739 2-amino-2-methyl-1-butanol 10196302Triethanolamine 102716 3-amino-3-methyl-2-pentanol 1646568201,3-propanediamine 109762 1-methyl-3-hydroxypiperidine 35547432-(2-aminoethoxy)ethanol 929066 dimethylethanolamine 1080102-(diethylamino)ethanol 100378 3-amino-1,2-propanediol 6163082-(diisopropylamino)ethanol 96800 Diethylenetriamine 1114002-(tert-butylamino)ethanol 4620706 Triethylenetetramine 112243Ethylenediamine 107153 Tetraethylenepentamine 1125722-Amino-2-Methyl-1,3-Propanediol 115695 hexamethylenediamine 124094

8

Structure - pKa RelationshipChain Length Effect

NameCAS

Registry No.

Molecular Formula

Structural Formula Type pKa* 25oC

pKa** Calculated

25oC

Primary Amines

Primary Alkanolamines

Monoethanolamine (MEA) 141-43-5 C2H7NO p 9.5 9.16±0.10

3-amino-1-propanol (MPA) 156-87-6 C3H9NO p 9.96 9.91±0.10

4-amino-1-butanol 13325-10-5 C4H11NO p10.38

@ 20oC10.32±0.10

5-amino-1-pentanol 2508-29-4 C5H13NO p10.46

@ 23oC10.47±0.10

Primary Diamines

Ethylenediamine (EDA) 107-15-3 C2H8N2 p(2)pK1 = 9.92 pK2 = 6.86

9.89±0.10

1,3-propanediamine 109-76-2 C3H10N2 p(2)pK1 =10.55 pK2 = 8.88

10.43±0.10

1,4- diaminobutane 110-60-1 C4H12N2 p(2)pK1 = 10.8 pK2 = 9.63

10.68±0.10

1,5-Pentanediamine 462-94-2 C5H14N2 p(2)pK1 = 10.05 pK2 = 10.93

10.85±0.10

hexamethylenediamine (HMDA) 124-09-4 C6H16N2 p(2)pK1 = 11.02 pK2 = 10.24

10.92±0.10NH2

NH2

NH2 NH2

NH2

NH2

NH2 NH2

H2N

NH2

NH2 OH

NH2

OH

NH2 OH

NH2

OH

9

Structure - pKa relationshipMultifunctional Amine Group Effect

NameCAS

Registry No.

Molecular Formula

Structural Formula Type pKa* 25oC

pKa** Calculated

25oC

1,4-Butanediamine 110-60-1 C4H12N2 p(2)pK1 = 10.8 pK2 = 9.63

10.68±0.10

Diethylenetriamine(DETA) 111-40-0 C4H13N3 p(2), spK1 = 9.94 pK2 = 9.13 pK3 = 4.34

10.16±0.10

1,5-Pentanediamine 462-94-2 C5H14N2 p(2)pK1 = 10.05 pK2 = 10.93

10.85±0.10

N-(2-aminoethyl)-1,3-propanediamine (AEPDA)

13531-52-7 C5H15N3 p(2), s 10.17±0.10

Hexamethylenediamine (HMDA) 124-09-4 C6H16N2 p(2)pK1 = 11.02 pK2 = 10.24

10.92±0.10

N-(3-aminopropyl)-1,3-propanediamine

56-18-8 C6H17N3 p(2), spK1 = 10.65 pK2 = 9.57 pK3 = 7.72

10.71±0.10

Triethylenetetramine (TETA) 112-24-3 C6H18N4 p(2), s(2)

pK1 = 9.92 pK2 = 9.20 pK3 = 6.67 pK4 = 3.32

10.05±0.19NH2

NH

NH

NH2

NH2 NH NH2

NH2

NH NH2

NH2

NH2

NH2 NH2

NH2

NH

NH2

NH2

NH2

10

Structure - pKa relationshipAlkyl Group Effect

NameCAS

Registry No.

Molecular Formula

Structural Formula Type pKa* 25oC

pKa** Calculated

25oC

Tertiary amine

Trimethylamine 75-50-3 C3H9N t 9.80 9.75±0.28

Triethylamine 121-44-8 C6H15N t 10.75 10.62±0.25

Tripropylamine 102-69-2 C9H21N t 10.66 9.99±0.50

Tertiary alkanolamine

dimethylethanolamine (DMEA) 108-01-0 C4H11NO t 9.23 8.88±0.28

2-(diethylamino)ethanol (DEAE) 100-37-8 C6H15NO t 9.75 9.79±0.25

3-(diethylamino)-1-propanol 622-93-5 C7 H17NO t 10.13±0.25

1-(diethylamino)-2-propanol 4402-32-8 C7H17NO t 10.27±0.25

N

N

N

N

OH

N

OH

N

OH

N OH

11

Structure - pKa RelationshipHydroxyl Group Effect-Primary Alkanolamine

NameCAS

Registry No.

Molecular Formula

Structural Formula Type pKa* 25oC

pKa** Calculated

25oC

Primary Alkanolamines

2-amino-2-methylpropanol (AMP)

124-68-5 C4H11NO p,(SH) 9.72 9.20±0.25

2-amino-1-butanol 96-20-8 C4H11NO p 9.67 @ 20oC 9.27±0.10

Monoisopropanolamine (MIPA)

78-96-6 C3H9NO p 9.62 @ 20oC 9.18±0.10

2-Amino-2-Methyl-1,3-Propanediol (AMPD)

115-69-5 C4H11NO2 p,(SH) 8.80 8.90±0.29

2-Amino-2-Ethyl-1,3-Propanediol (AEPD)

115-70-8 C5H13NO2 p,(SH) 8.80 8.86±0.29

2-amino-2-hdroxymethyl-1,3-propanediol (AHPD)

77-86-1 C4H11NO3 p,(SH) 8.07 7.78±0.29

OH

NH2

H2N

OH

HO OH

NH2

OH

NH2

NH2HO

HO

HO OH

NH2

HO

12

VLE Apparatus

CO2

Oil Bath

Equilibrium Cell

Cooler

CO2

Analyzer

Hygrometer

PT

FI

MFC1

N2

Cooler

N2 or CO2V

G10

VG11

VG8

VG12

VG9

VG13

VG15

VG7

VG3 VG1 VG5

VG4 VG2 VG6

GS2 GS1

LS2 LS1

GS3

VG14

Saf

ety

Val

ve

VP1 VP2

Gas Pump 2

Gas Pump 1

Gear Pump

Feed Pump

MFC2

PT

VG17

PT

TI

FT

TI

Am

ine

solu

tion

VL1VL2

VG

16

13

VLE Test Result

VLE 30wt% MEA 40oC

0.0

0.0

0.1

1.0

10.0

100.0

1000.0

10000.0

100000.0

0.0 0.2 0.4 0.6 0.8 1.0

Loading(molCO2/molMEA)

PC

O2(

kPa)

Loadingfresh

Jou, et. al (1995)

Loadingtitration

Sholeh

Shen and Li (1992)

14

Summary

• Several amines solvents have been suggested for CO2 Capture

• It appears there is relationship between amines structures and

their pKa value

• Effort is to explain this relationship using electron donation and withdrawal through bonds and solvation effect

• To know the benefit that could be derived from this relationship in CO2 capture process, particularly in solvent selection

• VLE Experiments continues

15

Thank You