Phase equilibrium modeling of structure H clathrate hydrates of methane + water "insoluble" hydrocarbon promoter Using QSPR molecular approach
Résumé
In this communication, the quantitative structure-property relationship (QSPR) strategy is applied to present two molecular models for determination of the structure H (sH) hydrate dissociation conditions with methane as help gas. Twenty-one water "insoluble" hydrocarbon promoters are examined. To propose reliable models, almost all of the available literature data are studied. Two mathematical methods including the genetic-algorithm-based multivariate linear regression (GA-MLR) and the least square support vector machines (LSSVM) are applied for determination (selection) of the model parameters. As a result, two reliable models are developed: (1) QSPR-GA-MLR linear model and (2) QSPR-LSSVM nonlinear model with satisfactory results quantified by the following statistical parameters: absolute average deviations (AAD) of the represented/predicted hydrate dissociation pressures from existing experimental values: about 9%, and squared correlation coefficient: 0.956 in the case of using the first model, and about 4% and 0.992 through applying the second model, respectively. These results demonstrate much better accuracy through the QSPR-LSSVM nonlinear model than applying the QSPR-MLR linear one.
Mots clés
Absolute average deviation
Clathrate hydrate
Equilibrium modeling
Experimental values
Hydrate dissociation
Least square support vector machines
Linear model
Literature data
Mathematical method
Model parameters
Molecular approach
Molecular models
Multivariate linear regressions
Non-linear model
Quantitative structure property relationships
Reliable models
Squared correlation coefficients
Statistical parameters
Dissociation
Genetic algorithms
Hydration
Least squares approximations
Methane
Nonlinear systems
Organic compounds
Phase equilibria
Support vector machines
Gas hydrates