Risk assessment is one of the main tools that oil and gas industries use to assess the hazards and risks in their facilities worldwide. Qualitative and quantitative risk assessments are carried out at various phases of the process industry: conceptual stage, design stage, construction stage, operational stage, decommissioning stage, etc. The quantitative risk assessment is directed during the detailed design stage to decide the spacing and layout out of equipment for safe operation and maintenance of oil and gas industries. The equipment layout and spacing are based on the safe distances are to be carried out on various design safety studies. In this work, a study was carried out on upstream onshore natural gas gathering stations and associated equipment and pipeline networks. The fire, explosion assessment, and toxic gas dispersion are conducted to evaluate how it affects people, assets, and the environment. Whether the design protection systems are adequate to mitigate the consequences or any additional measures to reduce risk to an acceptable level is analyzed.

Cylindrical shells are principal structural elements that are used for many purposes, such as offshore, sub-marine, and airborne structures. The nonlinear mechanics model of internal blast loading was established to predict the dynamic blast pressure of cylindrical shells. However, due to the complexity of the nonlinear mechanical model, the solution process is time-consuming. In this study, the nonlinear mechanics model of internal blast loading is linearized, and the dynamic blast pressure of cylindrical shells is solved. First, a mechanical model of cylindrical shells subjected to internal blast loading is proposed. To simplify the calculation, the internal blast loading is reduced to linearly uniform variations. Second, according to the stress function method, the dynamic blast pressure equation of cylindrical shells subjected to blast loading is derived. Third, the calculated results are compared with those of the finite element method (FEM) under different durations of dynamic pressure pulse. Finally, to reduce the errors, the dynamic blast pressure equation is further optimized. The results demonstrate that the optimized equation is in good agreement with the FEM, and is feasible to linearize the internal blast loading of cylindrical shells.