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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
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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
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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
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Carbon capture options (IPCC 2006). 4
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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
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Amine-based absorption-stripping system Freeman (2011) 6
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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
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Objectives of the study To propose a regression model that fits thermal degradation kinetic data with high accuracy. 8
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Methodology 9
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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
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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 1751.32*10 -7 0.981.20*10 -7 0.89 1653.14*10 -8 0.953.94*10 -8 0.88 1506.12*10 -9 0.968.63*10 -9 0.96 1359.69*10 -10 0.579.70*10 -10 0.56 Expression 6, First order kinetics Literature results Model results 1751.32*10 -7 0.981.20*10 -7 0.89 1653.14*10 -8 0.953.94*10 -8 0.88 1506.12*10 -9 0.968.63*10 -9 0.96 1359.69*10 -10 0.579.70*10 -10 0.56 11
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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 1754.94*10 -11 0.995.62*10 -11 0.91 1651.28*10 -11 0.941.22*10 -11 0.87 1501.49*10 -12 0.952.05*10 -12 0.96 1352.39*10 -13 0.582.40*10 -13 0.53 Expression 3, First order kinetics Literature results Model results 1754.94*10 -11 0.996.09*10 -11 0.99 1651.28*10 -11 0.947.95*10 -12 0.99 1501.49*10 -12 0.951.97*10 -12 1.00 1352.39*10 -13 0.581.64*10 -13 0.99 Expression 4, First order kinetics Literature results Model results 1754.94*10 -11 0.995.08*10 -11 0.84 1651.28*10 -11 0.931.17*10 -11 0.75 1501.49*10 -12 0.952.05*10 -12 0.95 1352.39*10 -13 0.582.37*10 -13 0.50 Expression 5, First order kinetics Literature results Model results 1754.94*10 -11 0.995.24*10 -11 0.99 1651.28*10 -11 0.941.77*10 -11 0.99 1501.49*10 -12 0.951.83*10 -12 0.99 1352.39*10 -13 0.585.06*10 -13 0.99 12
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Comparison of results obtained through expression 1 and 6 to those observed in the literature. 13
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Comparison of results of literature for k 2 and second order models of the study. 14
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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 0.99. 15
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Question and Answers 16
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Thank You..! 17
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