Stephanie Freeman January 10 th, 2007 Rochelle Group University of Texas at Austin – Dept. of Chemical Engineering

2 Presentation Outline  Introduction to ROC16 CO 2 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

3 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

4 CO 2 Solubility in ROC10 at 40°C Hilliard (2007) P CO2 = 7.5 kPa P CO2 = 0.75 kPa

5 Solubility of ROC20 At a loading of ~0.22, ROC20 is soluble at ambient temperature Hilliard (2007)

6 Solubility of ROC16 (cont.) Hilliard (2007) Current optimized absorber loadings

7 Expected Volatility at 40°C Hilliard (2007)

8 Kinetics: ROC16 vs. 7 m MEA  Comparison at 60°C, P CO2 * = 1 kPa  k g ’ = 1.5x10 -9 kmol/m 2 -Pa-s, 7.0 m MEA (a)  k g ’ = 2.7x10 -9 kmol/m 2 -Pa-s, ROC04 (b)  k g ’ for ROC16 was estimated (a)Aboudheir (2003) (b)Cullinane (2005) Rate of ROC16 is roughly 2X faster than 7 m MEA

9 Oxidative Degradation - Methods  Low gas flow experiments 100 mL/min 98% O 2 / 2% CO 2  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

10 Oxidative Degradation - Results Rate of Production mM/hr Solvent7 m MEAROC10ROC20 Metals Present0.6 mM Fe0.1 mM Fe 30 ppm Cr, 10 ppm Ni and Fe 250 ppm Cu Total Formate Glycolate Nitrite/Nitrate Amine Products Carbon in Products

11 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

12 Thermal Degradation over 5 weeks SolventT (°C)Loading Total Amine Loss (%) ROC ROC ROC m MEA m MEA

13 Conclusions  Faster rates of absorption (Cullinane 2005)  Higher capacity for CO 2 : Cap ROC16 = 1.44 mol CO 2 / kg solution Cap MEA = 0.84 mol CO 2 / kg solution  Negligible oxidative degradation (w/o Cu 2+ )  Negligible thermal degradation (potentially greater stripper P and T)  Comparable heat of absorption  Comparable volatilities A DVANTAGES OF ROC16 OVER MEA

14 Conclusions (cont.)  Increased viscosity decreases diffusion  Precipitation with loss of CO 2 loading or over-loading  Feasibility of onsite loading of ROC16  Narrow solubility range  Volatility management I SSUES THAT N EED TO BE A DDRESSED

15 Conclusions (cont.)  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” P OTENTIALLY I NTRACTABLE O BSTACLES

16 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

17 Questions?