Hydrogen Blending In Western Australia Gas Network - Pilbara Pipeline System

Abstract Hydrogen blending with natural gas (H2-NG blending) is a pragmatic solution to effectively mitigate and tackle the carbon footprint of natural gas consumption while providing an economical means of transporting large-scale H2. The study aims to evaluate the Pilbara Pipeline System for H2 transportation. It offers the effect of varying H2 concentrations within the gas mixture on the corrosion rates, erosional velocity ratio (EVR), and pressure performance at each 50 km interval along the pipeline. The APA Group's Pilbara Pipeline System spans 216 kilometers, transporting gas from the Burrup Extension Pipeline to Port Hedland with a capacity of 166 TJ/d. Using an innovative approach, we developed a simulation model in PIPESIM-Net software that integrates a GIS map to capture precise terrain profiles, calculate pressure drops, and accurately replicate steady-state gaseous flow. It incorporates parameters like pipeline specifications, and elevation, and specifies nodes (sink/source) with appropriate boundary conditions (pressure or flow rate), including the gas composition. Model accuracy was verified against historical data, and a sensitivity analysis assessed network performance by varying H2 concentration. The findings show that as the H2 concentration increases, the corrosion rate rises a little, with 80% H2 showing the highest corrosion rate, followed by a decrease in the H2 fraction every 10% and the reported corrosion rates (CRs) remain within the safe limits recommended by the National Association of Corrosion Engineers (NACE), which are less than 0.4 mm/a. This increased pressure along the pipeline due to higher levels of H2. However, the erosional velocity ratio exhibits a contrasting trend, increasing H2 composition resulted in a slight decrease in EVR. In all scenarios, the observed EVR values at checkpoints along the pipeline route remained below the safe limit of 1, indicating no erosion risk. The corrosion rates and EVR are both noteworthy for being within the industry-acceptable range, confirming the system's overall safety and practicality for blending H2-NG. This pioneering study comprehensively evaluates the impact of corrosion rate, EVR, and pressure profile on H2-NG blending in the Pilbara Pipeline System. Utilizing an innovative simulation model incorporating precise terrain profiles and elevation data, we provide novel insights into corrosion rates and EVR variations with H2 concentration. Our findings demonstrate the system's safety, and practicality, and address a significant research gap, illuminating corrosion, erosion, and pressure dynamics specific to this pipeline network.