Transcript ROC20: A Novel Amine Solvent for CO2 Capture

Stephanie Freeman
January 10th, 2007
Rochelle Group
University of Texas at Austin – Dept. of Chemical Engineering
Presentation Outline

Introduction to ROC16
 CO2 Solubility
 Solid-Liquid Equilibrium of ROC16
 Volatility of ROC16
 Capacity and Viscosity
 Comparison of Kinetics
Oxidative Degradation with Metals
 Thermal Degradation
 Conclusions and Current Issues
 Future Work on ROC16

2
Introduction to ROC16
3

ROC16 is a novel amine solvent
recently patented by the Rochelle Group

The Rochelle group is currently
investigating ROC16 as an viable
alternative to 7 m MEA
Hilliard (2007)
CO2 Solubility in ROC10 at 40°C
10
CO2 Partial Pressure (kPa)
PCO2 = 7.5 kPa
1
PCO2 = 0.75 kPa
0.1
0.25
4
Rich Loading = 0.42
Lean Loading = 0.33
0.3
0.35
0.4
Loading (mol CO2/mol ROC10)
0.45
Hilliard (2007)
Solubility of ROC20
50
ROC20
ROC10
At a loading of
~0.22, ROC20 is
soluble at ambient
temperature
Temperature (°C)
40
30
ROC04
20
10
0
0.00
5
0.10
0.20
0.30
0.40
Loading (mol CO2/mol ROC20)
Hilliard (2007)
Solubility of ROC16 (cont.)
50
ROC20
Current
optimized
absorber
loadings
ROC10
Temperature (°C)
40
30
ROC04
20
10
0
0.00
6
0.10
0.20
0.30
0.40
Loading (mol CO2/mol ROC20)
Hilliard (2007)
Expected Volatility at 40°C
PAmine/[Amine] (kPa/m)
0.001
7 m MEA
ROC10
0.0001
0.01
7
0.1
1
PCO2 (kPa)
10
Kinetics: ROC16 vs. 7 m MEA
Comparison at 60°C, PCO2* = 1 kPa
 kg’ = 1.5x10-9 kmol/m2-Pa-s, 7.0 m MEA(a)
 kg’ = 2.7x10-9 kmol/m2-Pa-s, ROC04 (b)
 kg’ for ROC16 was estimated

k 'g, 
Amine D  A μ-0.8
 k'g,ROC16
 '
k
 g,ROC04




 AROC16

 AROC04
 μROC04

 μROC16



0.8

~ 4~ 0.150.8  1
Rate of ROC16 is roughly 2X
faster than 7 m MEA
8
(a) Aboudheir (2003)
(b) Cullinane (2005)
Oxidative Degradation - Methods
 Low gas flow experiments
 100 mL/min 98% O2 / 2% CO2

Analysis using Anion and Cation IC to
detect:





Organic acids (formate, acetate, etc.)
Inorganic ions (nitrite and nitrate)
Amides (through formate production)
Amines
Not yet testing for:
 Amino Acids
 Aldehydes
9
Oxidative Degradation - Results
Rate of Production mM/hr
Solvent
7 m MEA
ROC10
ROC20
ROC20
0.6 mM Fe
0.1 mM Fe
30 ppm Cr, 10
ppm Ni and Fe
250 ppm Cu
Total Formate
0.40
0.01
0.011
0.42
Glycolate
0.10
0
0
0
Nitrite/Nitrate
0.46
0.001
0.001
0.01
-
-
0
0.39
0.73
0.05
0.016
1.24
Metals Present
Amine Products
Carbon in Products
10
Thermal Degradation - Methods
 Degradation
of ROC20 studied at
135°C and 150°C
 Loadings of α=0.3 and α=0.4
 Stainless
steel bombs used
 Amine concentration analyzed by:
 Cation IC
 Acid pH titration
11
Thermal Degradation over 5 weeks
Solvent
T (°C)
135
ROC20
150
12
Loading
Total Amine
Loss (%)
0.3
4
0.4
5
0.3
0
0.4
-2
ROC30
150
0.3
0
ROC40
150
0.3
2
7 m MEA
135
0.4
29
7 m MEA
150
0.4
84
Conclusions
ADVANTAGES OF ROC16 OVER MEA
Faster rates of absorption (Cullinane 2005)
 Higher capacity for CO2:

 CapROC16 = 1.44 mol CO2 / kg solution
 CapMEA = 0.84 mol CO2 / kg solution
Negligible oxidative degradation (w/o Cu2+)
 Negligible thermal degradation (potentially
greater stripper P and T)
 Comparable heat of absorption
 Comparable volatilities

13
Conclusions (cont.)
ISSUES THAT NEED TO BE ADDRESSED
Increased viscosity decreases diffusion
 Precipitation with loss of CO2 loading or
over-loading
 Feasibility of onsite loading of ROC16
 Narrow solubility range
 Volatility management

14
Conclusions (cont.)
POTENTIALLY INTRACTABLE OBSTACLES

Pseudo-polymerization of ROC16
 Rapid increase in viscosity
 Trigger unknown

Anomalous gas/liquid behavior
 Oxidation experiments with either Fe/Cr/Ni
or Cu produced some kind of “foam”
15
Future Work on ROC16






16
Additional degradation experiments with
higher concentrations of Cr, Ni, and Fe
Obtain rate data for ROC16
Further study phase equilibrium behavior of
ROC16
Investigate pseudo-polymerization
Develop plausible onsite loading
procedures
Determine true extent of foaming
Questions?
17