Probabilistic Assessment of Hydrogen Transportation System Components

Abstract Many countries are planning to transport hydrogen through existing natural gas pipeline infrastructure. The integrity of pipelines for hydrogen service has been examined extensively, but other components in the system, such as valves, compressors, pressure regulators, and many other discrete devices, have not been evaluated to any great extent. This paper presents a uniform approach to modeling the performance of these components under hydrogen blend service using a Bayesian network method. The baseline failure rate of system components under natural gas transport can be derived from industry databases. The Bayesian network approach modifies the baseline failure rates for hydrogen service by modeling the interactions of hydrogen with various materials in the system components. For each component, the materials, stresses, and environments are linked through conditional probabilities to predict failure modes. For metallic materials, the failure modes may be corrosion, fatigue life, or fracture resistance, leading to either integrity threat or loss of function (e.g., failure of a valve to close on demand). For elastomeric materials, the failure modes may be permanent set or volume change resulting in leaks. Examples of the approach for compressors, valves, and regulators are shown.