A non-linear model is developed to capture the transient flow and pressure behaviour of methane-rich gas (MRG) in industrial pipelines for the use in simulation and control applications. Hyperbolic partial differential equations describe the pipe pressure and flow profiles, and composition analyses are used to develop the physical properties of the gas appearing in the pipe segment equations. The spectral element method (SEM) is used to numerically solve the spatial profiles within the pipeline, and a model verification is done on the SEM tuning parameter choices. The model is developed into a compact state–space description for improved usability. Furthermore, the developed model achieves good accuracy when validated on real process data of an industrial MRG network and can be used for simulation and model-based control applications.