H2 and H2 Blends with Natural Gas Transportation in Offshore Pipelines: An Overview from Flow Assurance Perspective

Abstract

Abstract The use of offshore existing or new pipeline is a solution to deliver the blue / green hydrogen at reduced transport cost and in proximity of final users. Pipeline design and repurposing for hydrogen transportation require the use of commercial design tools, originally developed for hydrocarbons. The applicability of available design tools shall be assessed versus. available experimental data and academic studies findings to understand the current applicability range of the design tools and the areas of further improvements of commercial software to model green H2 and H2 + Natural Gas blends, with focus on thermophysical properties relevant to transport and hydrate estimation capabilities in the identified operating ranges. Thermodynamic tools are used to evaluate the phase behavior, thermodynamic data, and potential operational issue (like hydrate formation risk). Fluid dynamic tools are needed for the assessment of hydraulic performance and to generate inputs for mechanical sizing. The combination of both tools to develop models is the first step for the pipeline design. This work will present the results obtained for multiple case studies of H2 and H2 blends transportation in offshore pipelines. Sensitivities have been performed with available EOSs considering different H2 rich mixture compositions and up to date available software. The results obtained with the models and typically used for the design, like pressure, temperature, density, velocity profiles, are compared and discussed. The outcome of this work is to present the status of available tools in the industry and open the discussion with interested parties about areas of improvement and the future development to cover the design requirements for H2 and H2 blends pipelines.