Analysis of static electricity risks in nonmetallic pipelines for hydrogen transportation.

Nonmetallic pipelines are promising for medium-short distance hydrogen transport due to their lightweight, corrosion resistance, and durability. However, their low conductivity raises electrostatic safety concerns, given hydrogen's exceptionally low ignition energy (0.017 mJ). This study employs electrostatic double-layer theory to quantify electrostatic risks under varying parameters, such as conductivity of nonmetallic materials, flow velocity, pipe diameter, and operating parameters including hydrogen pressure and temperature. The results indicate that lower electrical conductivity of nonmetallic materials, higher flow velocity and larger pipe diameter will increase the accumulation of static electricity. However, the accumulated static electricity energy in nonmetallic pipelines remains significantly below the minimum ignition potential of hydrogen, indicating a lower static electricity risk in nonmetallic pipelines. In addition, the static electricity risks of pipelines with different transportation media and pipeline materials were compared. Considering factors such as pipe surface roughness, electrical conductivity, and the ignition energy of the transportation medium, nonmetallic hydrogen pipelines exhibit lower static electricity risks. Existing applications have never reported electrostatic accidents in nonmetallic hydrogen pipelines, which also indicates that nonmetallic hydrogen pipelines have lower electrostatic risks. The results in this study could provide guidance for the application and safety evaluation of nonmetallic pipelines for hydrogen transportation.