Computational Fluid Dynamics (CFD) Transient Pressure and Temperature Simulation of a Natural Gas– Hydrogen Gas Blend Transportation Pipeline

The need for a CFD exploratory investigation into the possible effect of hydrogen injection into existing natural gas pipeline network, was the driver for this study. Recent technical feasibility reports on transporting a blend of both gases (JIR, 2019), did not mention if a study was done to rule out the possible effect of natural gas-hydrogen blend on hydrate formation in a hydrate-prone gas pipeline. A CFD model of 0.0508m and 10m length, with a mesh size of 20,000 elements was developed and simulated using ANSYS Fluent version R19.3. Hydrogen concentration by volume of 5%, 10%, 15% and 20% were simulated at velocities of 5m/s and 10m/s. The results indicated that increasing the volume concentration of hydrogen gas in the blend led to a reduction of downstream temperature. Again, the force on the inner wall decreased as the volume of hydrogen injected increased. The inference was that the reduction in temperature could lead to hydrates formation, whereas the reduction in exerted force on the pipe wall by the fluid could suggest a reduction in turbulence. However, this study was exploratory in nature and it is recommended that a detailed experimental study be carried out to clearly define the hydraulic and thermal behavior of a pipeline transporting a natural gas-hydrogen blend under various subcooling temperatures.