New equation refines vapor pressure calculations for diverse conditions

The Korea Institute of Civil Engineering and Building Technology has introduced a vapor pressure equation. It addresses the limitations of the Lee-Kesler method, which has been a widely used method in the field of thermodynamics, offering a versatile and comprehensive solution for vapor pressure calculations across diverse conditions.

The study is published in the journal Chemical Engineering Communications.

The Lee-Kesler method has been a reliable calculation method in chemical process design, particularly for predicting vapor pressure based on material properties. By referring the acentric factor, it accounts for non-ideal behavior and delivers stable, accurate results, even near critical points.

Its simplicity—requiring only the acentric factor and critical properties—has made it a preferred alternative to Antoine’s equation, which depends on extensive substance-specific temperature data. However, its limitations in temperature range and accuracy at lower temperatures have long posed challenges.

Dr. Lee Jaiyeop of KICT developed this new equation, which represents a significant improvement, achieving an impressive average error rate of 0.49%, slightly better than the Lee-Kesler method’s 0.50%. In a study involving 76 substances, it outperformed the Lee-Kesler method in 45 cases.

Most notably, at reduced temperatures below 0.7, the equation demonstrated an average error rate of 0.57%, compared to the Lee-Kesler method’s 0.72%. This enhanced precision at relatively lower temperatures could be particularly valuable for cryogenic and other extreme environments such as Antarctica or the lunar surface.

A key breakthrough is its extended temperature range. While the Lee-Kesler method is restricted to calculations around a reduced temperature of 0.7, the new equation is applicable across a broad range, from 0.25 to 0.95. This flexibility makes it suitable for substances with limited experimental data, addressing the data dependency challenges faced by other methods. Consequently, it provides a more adaptable and efficient computational environment for engineers and researchers.

The equation has received international recognition as a significant extension of the Antoine and Lee-Kesler methods. Its potential applications span diverse fields, including energy, pharmaceuticals, and environmental monitoring. Its precision and versatility make it a valuable tool for addressing high-pressure and low-temperature challenges in industrial operations.

Moreover, the equation is designed to integrate seamlessly with IoT-based monitoring systems. This compatibility enables real-time data analysis and process optimization, which are expected to enhance productivity and safety across industries. By bridging theoretical innovation with practical applications, this new approach promises to set a new benchmark in vapor pressure calculations.

Dr. Lee said, “This research not only sets a new benchmark but also introduces a transformative tool for the chemical engineering community.”

He mentioned that with its adoption, industries are expected to achieve significant advancements. As its influence grows, this groundbreaking equation is set to leave a lasting mark across various disciplines.