🤖 AI Summary
This study addresses the well-known limitations of conventional cubic equations of state—such as the Peng–Robinson equation (PR-EOS)—in accurately predicting vapor–liquid equilibrium (VLE) for hydrocarbon–nitrogen mixtures, as well as the lack of interpretability in existing deep learning approaches. To overcome these challenges, the authors propose the first interpretable correction framework based on symbolic regression. Their two-stage strategy first derives symbolic correction terms from experimental VLE data for individual hydrocarbon systems, then models the resulting correction coefficients as explicit functions of carbon number, enabling unified generalization across varying chain lengths. This approach significantly enhances the predictive accuracy of PR-EOS while preserving physically meaningful analytical expressions, thereby achieving a balanced trade-off between accuracy and interpretability.
📝 Abstract
Accurate prediction of vapor--liquid equilibrium (VLE) for hydrocarbon-nitrogen mixtures remains challenging for cubic equations of state, particularly across broad ranges of composition and hydrocarbon chain length. While deep learning models can provide accurate predictions, they often lack interpretability and explicit analytical expressions. In this work, we propose a symbolic machine learning approach to discover interpretable symbolic corrections to Peng-Robinson equation-of-state (PR-EOS) predictions from experimental data. The proposed approach adopts a two-level strategy: symbolic expressions are first identified for individual hydrocarbon systems, after which their coefficients are represented as functions of carbon number to enable accurate prediction across different hydrocarbon systems. The results demonstrate significantly improved prediction accuracy over the original PR-EOS across all hydrocarbon-nitrogen systems. Overall, the proposed approach provides an interpretable symbolic correction framework for improving PR-EOS predictions of hydrocarbon-nitrogen VLE.