A review on hydrogen blending in gas network: Insight into safety, corrosion, embrittlement, coatings and liners, and bibliometric analysis

Performance Evaluation of an Anode-Supported SOFC Short-Stack Operating with Different Fuel Blends as Stationary-CHP System

“…13 Given the different physical and chemical characteristics of hydrogen compared to the natural gas, with the current gas grid this condition is all but guaranteed: the high permeability of the hydrogen molecule makes it prone to diffuse into the metallic lattice, 14 causing embrittlement and pipeline corrosion. 15 Embrittlement is the permeation of the molecules through the steel structure, whose consequences are loss in material ductility and strength, as well as material failure; the fracture toughness of the metal can be reduced to one tenth of its original value. 14 Corrosion is electrochemical material deterioration, 16 a phenomenon exacerbated by the presence of impurities such as sulphur, chloride, CO 2 in the gas mixture.…”

“…14 Corrosion is electrochemical material deterioration, 16 a phenomenon exacerbated by the presence of impurities such as sulphur, chloride, CO 2 in the gas mixture. 15 The issue can be tackled by using coatings (organic, inorganic or metallic layers 17 ) that work as barriers to prevent excessive exposure of metal materials to hydrogen and impurities. 15 The compatibility with H 2 -NG of the current gas grid pipelines appears to be a big concern, and numerous studies and research projects conducted in recent years have explored different case studies.…”

“…15 The issue can be tackled by using coatings (organic, inorganic or metallic layers 17 ) that work as barriers to prevent excessive exposure of metal materials to hydrogen and impurities. 15 The compatibility with H 2 -NG of the current gas grid pipelines appears to be a big concern, and numerous studies and research projects conducted in recent years have explored different case studies. 15 It has been shown that, when working with low gas pressure, hydrogen leakage is comparable to NG leakage; as the operating pressure rises, H 2 leaks more easily.…”

“…15 The compatibility with H 2 -NG of the current gas grid pipelines appears to be a big concern, and numerous studies and research projects conducted in recent years have explored different case studies. 15 It has been shown that, when working with low gas pressure, hydrogen leakage is comparable to NG leakage; as the operating pressure rises, H 2 leaks more easily. 13 Moreover, improper injection (hence mixing) of H 2 with NG can lead to separation of the two gas streams, causing higher levels of leakages and pipeline material degradation.…”

“…13 Moreover, improper injection (hence mixing) of H 2 with NG can lead to separation of the two gas streams, causing higher levels of leakages and pipeline material degradation. 15 ENTSOG have shown that in case of very low presence of hydrogen into the gas mixture (blending percentage of up to 2%vol in NG), no specific adaptations in the infrastructure nor measures of any kind need to be taken, regardless of the operating pressure; for higher concentrations of H 2 this might not be true. 13,18 Sánchez-Laínez et al 13 have tested the most common pipelines material transporting a 20%vol H 2 in NG at 80 bar: the experimental campaign lasted 3000 h and still no significant embrittlement consequence was found.…”