Stephanie FreemanJanuary 10th, 2007

Rochelle GroupUniversity of Texas at Austin – Dept. of Chemical Engineering

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Presentation Outline Introduction to ROC16

CO2 Solubility

Solid-Liquid Equilibrium of ROC16Volatility of ROC16Capacity and ViscosityComparison of Kinetics

Oxidative Degradation with Metals Thermal Degradation Conclusions and Current Issues Future Work on ROC16

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Introduction to ROC16 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

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CO2 Solubility in ROC10 at 40°CHilliard (2007)

PCO2 = 7.5 kPa

PCO2 = 0.75 kPa

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Solubility of ROC20

At a loading of ~0.22, ROC20 is

soluble at ambient temperature

Hilliard (2007)

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Solubility of ROC16 (cont.)Hilliard (2007)

Current optimized absorber loadings

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Expected Volatility at 40°CHilliard (2007)

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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

(a) Aboudheir (2003)(b) Cullinane (2005)

-0.8'g, μADAminek

10.15~4~

μ

μ

A

A

k

k 0.8

0.8

ROC16

ROC04

ROC04

ROC16'

ROC04g,

'ROC16g,

Rate of ROC16 is roughly 2X faster than 7 m MEA

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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 AcidsAldehydes

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Oxidative Degradation - Results

Rate of Production mM/hr

Solvent 7 m MEA ROC10 ROC20 ROC20

Metals Present 0.6 mM Fe 0.1 mM Fe30 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

Amine Products - - 0 0.39

Carbon in Products 0.73 0.05 0.016 1.24

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Thermal Degradation - Methods

Degradation of ROC20 studied at 135°C and 150°CLoadings of α=0.3 and α=0.4

Stainless steel bombs used Amine concentration analyzed by:

Cation ICAcid pH titration

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Thermal Degradation over 5 weeks

Solvent T (°C) LoadingTotal Amine

Loss (%)

ROC20

1350.3 4

0.4 5

1500.3 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

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Conclusions

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

ADVANTAGES OF ROC16 OVER MEA

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Conclusions (cont.)

Increased viscosity decreases diffusion Precipitation with loss of CO2 loading or

over-loading Feasibility of onsite loading of ROC16 Narrow solubility range Volatility management

ISSUES THAT NEED TO BE ADDRESSED

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Conclusions (cont.)

Pseudo-polymerization of ROC16Rapid increase in viscosityTrigger unknown

Anomalous gas/liquid behavior Oxidation experiments with either Fe/Cr/Ni

or Cu produced some kind of “foam”

POTENTIALLY INTRACTABLE OBSTACLES

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Future Work on ROC16

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

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Questions?