Quantitative risk study on explosion accident of PSA hydrogen purification unit

Objective The aim is to reasonably determine the explosion risk of pressure swing adsorption(PSA) hydrogen purification unit and the anti-explosion fortification load of surrounding buildings so as to support the anti-explosion design and protection.

Method Taking PSA hydrogen purification unit as an example, CFD simulation was used to construct 40 explosion calculation scenarios to identify the three-dimensional distribution of explosion risk of hydrogen purification unit and its influence on the people gathering buildings.

Result According to the acceptable risk criterion of 10⁻⁴ times per year and the maximum explosion overpressure criterion within the acceptable risk range, anti-explosion transformation or design should be carried out on the people gathering building within 85 m distance from the adsorption tower skids of the hydrogen purification unit. Besides, this study also showed that the peak incident overpressure of the explosion shock wave of the people gathering building wall on the north side of the typical PSA unit is 9.4 kPa, and the maximum explosive impulse was 318 Pa·s, which requires anti-explosion transformation.

Conclusion With the consideration of the effects of the actual layout of the unit and obstacles on hydrogen leakage as well as diffusion and explosion overpressure, while eliminating the effects of scenarios with high consequences and low probability on the explosion protection value proof load, the quantitative analysis of explosion risk based on CFD in this study could provide an effective basis for the safe distance setting of PSA unit and the anti-explosion renovation or design of people gathering buildings.