Determination of the intrinsic rate constant and activation energy of CO 2 gas hydrate decomposition using in-situ particle size analysis

Abstract

Experimental data on the rate of decomposition of CO 2 gas hydrates has been obtained using a semi-batch stirred tank reactor, with an in-situ particle size analyser, at temperatures ranging from 274 to 281 K and pressures ranging from 1.4 to 3.3 MPa . A method for calculating the moments of the particle size distribution has been presented. The experimental data was analysed using the kinetic model of Clarke and Bishnoi (Determination of the intrinsic kinetics of gas hydrate decomposition kinetics using particle size analysis, Presented at the Third International Conference on Gas Hydrates, Salt Lake City, Utah, July 18–22, 1999; Chem. Eng. Sci. 55 (2000) 4869) in its differential form in order to account for the slight change in temperature during the decomposition of CO 2 hydrates. The applicability of the new instrument for measuring gas hydrate decomposition kinetics was examined by conducting experiments with ethane at conditions similar to those encountered by Clarke and Bishnoi (2000). It was seen that the previously obtained rate constants for ethane hydrate decomposition were able to predict the new obtained data. A new procedure for regressing the intrinsic rate constant and activation energy has also been described and it is seen that the activation energy is 102.88 kJ/ mol and the intrinsic rate constant is 1.83×10 8 mol/( m 2 Pa s ) for CO 2 gas hydrate decomposition.