Mathematical Modelling and Dynamic Simulation of the Ethan Separation Unit in Natural Gas Liquefaction Plant

Abstract; Separation is one of the most important processes in all chemical industries, including the petroleum industry. Ethane gas separation is the simplest example of a gas mixture separation process. A mathematical model and dynamic simulation of the ethane gas separation unit at a natural gas liquefaction (NGL) plant were developed, focusing on developing an accurate mathematical representation that relies solely on temperature as the main dynamic variable, without introducing flow rate or pressure effects. This allows for a flexible and realistic simulation of the system's behaviour. The mathematical model was built using first-order differential equations that describe the temporal relationship between the temperatures at the inlets and outlets of the system components using matrix algebra. Actual operational data recorded from the work site were used, providing the model with a high degree of reliability and validity in simulating the system's actual performance under both steady-state and unsteady-state operating conditions. The simulation was implemented using the MATLAB/Simulink environment to represent the thermal relationships and analyze the dynamic interaction between the system units. The model results demonstrate good agreement with practical applications, making it possible to provide a ready-to-use simulation as a testbed for advanced process monitoring or operational decision support. Through system simulation, the model's ability to accurately and realistically represent system behaviour was demonstrated, matching the actual operational behavior with the help of gain factors. This work represents a qualitative contribution to the field of modelling industrial thermal systems and paves the way for further development toward building more comprehensive models for gas processing units.