Quantitative risk assessments of hydrogen blending into transmission pipeline of natural gas

Recently, considerable attention has been paid to blending hydrogen with natural gas transmission pipelines. However, risk assessments using different hydrogen blend concentrations in natural gas pipelines have not been thoroughly investigated. Thus, the main objective of this study is to carry out a quantitative risk assessment of hydrogen blending into the transmission of natural gas. For this, six different concentrations of hydrogen blending, three pipes and four different release holes are used in this study. The effect distance decreased with increasing hydrogen concentration for the jet fire case. For case of vapor cloud explosions, the downwind distance of the maximum explosion overpressure increased with increasing hydrogen concentration. It was also found that as the hydrogen concentration increased, the individual risk was sensitive to adjacent to the pipelines, however, it was less for far-fields. This study is expected to contribute to the safety measures for business sites with hydrogen blending into natural gas pipelines.