(129c) The Melhorado Process Hazard Analysis (mPHA) – Enhanced Risk Assessment Method for Mature Operating Facilities

ABSTRACT

Technical safety risk assessment aims to identify, assess, prioritize and mitigate process safety risks through standardized qualitative and quantitative approaches. Efficient and cost-effective planning is essential for successful risk assessments.

Process Hazard Analysis (PHA), a set of organized and systematic assessments, evaluates hazards associated with industrial processes. However, traditional PHA techniques like HAZOP can be time-consuming, resource-intensive, and often involve the recycling of recommendations, leading to inefficiencies. Additionally, the remoteness of the facility and rotational crew schedules add to the complexity of executing studies, delivering valuable outcomes and ensuring consistency.

To address these challenges, Angola LNG developed melhorado PHA (mPHA), an improved and enhanced approach to streamline the PHA revalidations for a mature operating facility. Adapted from IChemE’s Delta HAZOP, this approach utilizes existing PHA studies and focuses on identifying risks associated with the subtle and creeping changes. mPHA method includes three phases (i) pre-workshop (discipline lead), (ii) workshop (team based) and (iii) post workshop (smaller focused team).

This paper discusses Angola LNG’s four-year journey in developing and maturing mPHA, a fit-for purpose approach implemented at LNG plant operated for a decade. The paper highlights the significance of pre-workshop activities and of involving the right people, which include subject matter experts, experienced operational representatives and an independent facilitator. Systematic preparation and analysis help identify any addition or deletion of hazards, assess the effectiveness of process safety safeguards (barriers) and evaluate changes in the demand to these safeguards. The mPHA approach, reduced the over-all team time by 50%, ensured effective safeguards were in-place and eliminated risk management recommendations.