REGRESSION MODELING OF THERMAL DEGRADATION KINETICS, OF CONCENTRATED, AQUEOUS PIPERAZINE IN CARBON DIOXIDE CAPTURE Idris Mohamed Saeed Department of chemical engineering, university of Malaya, Kuala Lumpur, Malaysia. 1
Climate change and its Consequences Melting glaciers. Rise in temperature. Thunderstorms. Wildfires. Floods. Droughts. “I believe global warming and climate change are real threats to our planet.” -Andrew Cuomo 2
Global CO 2 emissions CO 2 emissions increased by 71% from 1990 to 2010 (IEA, 2012). Global CO 2 emissions can grow up to 29% by the year 2035, which are nearly double to that of 1990 (BP Outlook, 2014). Reduction in 50% of the global CO 2 emissions would be compulsory to limit temperature from 2 to 2.4 °C by the year 2050 (IPCC, 2013). 3
Carbon capture options (IPCC 2006). 4
Why amine scrubbing technology? Retrofitting the existing fleet of power plants. More than 85 per cent of the CO 2 from flue gas can be captured (CSIRO). Economically feasible under specific conditions (IPCC 2006). Overall thermodynamic efficiency of 50% ( Rochelle et al., 2011). A number of pilot plants tested. 5
Amine-based absorption-stripping system Freeman (2011) 6
Solvents and their management Solvent makeup costs 10% of the operating (Rubbin and Rao 2002). Traditional amines used: Monoethanolamine Diethanolamine Methyldiethanolamine Amino-methylpropanol New amines of interest: Piperazine Morpholine 7
Objectives of the study To propose a regression model that fits thermal degradation kinetic data with high accuracy. 8
Methodology 9
Linear and Nonlinear forms of first and second order rate equations ExpressionTypeEquationCurve fitting (Y Vs X) Expression 1, First Order LinearlnC PZ Vs t Expression 2, Second Order Linear1/C PZ Vs t Expression 3, Second Order Linear1/C PZ.t Vs 1/t Expression 4, Second Order LinearC PZ /C PZ0 Vs C PZ.t Expression 5, Second Order Quadratict/C PZ0 Vs t Expression 6, First Order ExponentialC PZ Vs t 10
First order rate models results for thermal degradation of 8 m PZ with 0.3 mole CO 2 per mole alkalinity initially at 135 °C to 175 °C. Temperature (°C)k 1 ( s -1 )R2R2 R2R2 Expression 1, First order kinetics Literature results Model results * * * * * * * * Expression 6, First order kinetics Literature results Model results * * * * * * * *
Results of k 2 of second order models of thermal degradation of 8 m PZ with 0.3 mole CO 2 per mole alkalinity initially at temperatures, 135 °C to 175 °C. Temperature (°C) k 2 (kg/mmol.s) R 2 k 2 ( kg/mmol.s)R2R2 Expression 2, First order kinetics Literature results Model results * * * * * * * * Expression 3, First order kinetics Literature results Model results * * * * * * * * Expression 4, First order kinetics Literature results Model results * * * * * * * * Expression 5, First order kinetics Literature results Model results * * * * * * * *
Comparison of results obtained through expression 1 and 6 to those observed in the literature. 13
Comparison of results of literature for k 2 and second order models of the study. 14
Conclusions Thermal degradation data o PZ is found to follow both first order and second order kinetics. Conventional equations failed to present better results for second order kinetics, especially at 135 °C. The results of first order rate models, expressions 1 and 6 and second order models, expressions 2 and 4 are in agreement with the results of literature. Expression 3, in the linear form and expression 5, in quadratic form provides the most feasible fits with R 2 values higher than
Question and Answers 16
Thank You..! 17