Environmental Risk Assessment of a Hydrocracker Unit in Abadan Oil Refinery Using the EFMEA Analysis

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workers. 26Risk assessment provides vital data for decision-making aimed at mitigating risks, improving the environment, managing hazardous facilities, emergency planning, determining acceptable risk levels, and establishing audit and maintenance schemes for industrial facilities, among other purposes. 27efining plants have made significant technological advancements in recent decades, but this progress has also brought about increased workplace risks and hazards, resulting in substantial financial losses for the industry. 28o address these hazards, an effective management system is necessary to mitigate risks, ensure employee safety and well-being, and safeguard the environment.It is of utmost importance to prioritize safety and implement measures such as accident analysis, hazard identification, and risk assessment in the oil and gas industries.These industries are particularly prone to accidents like explosions and fires due to the nature of their processes and materials used.For instance, the fire incident at the UMM SAUD Refinery Plant in Qatar in 1977 resulted in seven fatalities, 12 injuries, and financial damages of US$ 210.8 million, while the gas explosion at the ABQAIQ Refinery Plant in Saudi Arabia in 1978 caused no casualties but led to financial losses of US$ 148.9 million. 29Therefore, emphasizing safety and implementing measures such as accident analysis, hazard identification, and risk assessment are crucial in preventing accidents.Gas leaks in the gas path flanges and the associated fire and explosion hazards can have detrimental effects on water, soil, and air pollution throughout the lifecycle of these plants.
Failure modes and effects analysis (FMEA) is a widely utilized technique for system safety analysis.It was initially introduced in the late 1950s by an engineer and served as a dependable method for evaluating the safety of military systems.Since then, its applications have significantly expanded. 30This quantitative analysis technique examines a system or sub-system to identify potential faults in its components and assesses the potential impacts of these faults on other parts of the system. 31On the other hand, environmental failure modes and effects analysis (EFMEA) is a qualitative approach employed during the product development process to identify and prioritize significant environmental factors in a timely and efficient manner. 32Consequently, this study aimed to assess the safety, health, and environmental risks associated with the hydrocracker unit in the Abadan oil refinery plant using EFMEA.

Materials and Methods
The operations conducted within the hydrocracker unit at Abadan oil refinery encompass life cycle operations, control room operator duties, on-site staff activities, and maintenance tasks for the hydrocracker unit.
This study, utilizing a descriptive-cross-sectional approach, aimed to identify and assess safety, health, and environmental risks within the hydrocracker unit of the Abadan oil refinery plant through EFMEA.The EFMEA analysis was utilized to precisely evaluate occupational hazards and implement hazard mitigation measures in accordance with the severity of identified risks.The rationale for utilizing this approach is rooted in its extensive utilization within the realm of quality engineering and management tools in our country, as highlighted by Darvishi et al. 32 This technique involves assembling a team composed of a safety expert, plan executor, production supervisor, and technical expert, as well as collecting data to carry out occupational safety analysis.Jobs necessitating such analysis are selected based on their accident history and the hazards associated with each job.Subsequent to a safety evaluation that considers observations, documents, preliminary investigations, and hazard checklists, the most suitable candidates for occupational safety analysis are prioritized for evaluation.Hazard identification is accomplished through the implementation of EFMEA.The execution and implementation of this method necessitate collaboration within a professional HSE committee to identify hazards and assess risks.Consequently, in the current study, the hazards present on the site were identified by recruiting one professional health expert, two environmental health experts, two safety experts, and one master of industrial engineering.Risks were then ranked and evaluated in terms of intensity, occurrence probability, detection probability, pollution scope, and recycling possibility, utilizing the expertise of the professionals and standard tables employed in EFMEA.Subsequently, risk classification was performed, categorizing the hazards into low, moderate, and high risks, and corresponding measures were taken accordingly.

Results and Discussion
The hydrocracker unit at Abadan oil refinery involves various activities, including life cycle operation, control room operators' tasks, site staff activities, and hydrocracker unit repairs.During the analysis, a total of 34 risks associated with these activities were identified.The evaluation of these identified risks, including their probability, intensity, detection probability, and Risk Priority Number (RPN), is discussed in the following section.

Life Cycle Operations
The risk evaluation of life cycle operations in the hydrocracker unit at the Abadan refinery plant, as shown in Table 1, revealed that the highest risk priorities were attributed to gasket failure, valve control failure, and path (pipe) perforation.These specific risks were identified as having the greatest potential impact and were thus given the highest priority for mitigation and management.

Control Room Operators
The results of the risk assessment for control room operators in the hydrocracker unit of the Abadan refinery plant have been presented in Table 2.The findings highlight that the highest priority risk was associated with the potential technical failure of certain alarms, leading to the non-transmission of control room alarms.

Staff Activities in Open Sites
Results of site staff activities' risk evaluation in the Abadan refinery plant's hydrocracker unit indicated that failure to use personal protective gear had the highest risk priority (Table 3).

Maintenance
According to the findings presented in Table 4, the maintenance risk evaluation conducted at the hydrocracker unit of the Abadan refinery plant revealed that the failure to utilize personal protective gear was assigned the highest priority in terms of risk.
The risk level and index for each activity were determined according to Table 5 using the statistical technique of confidence intervals.Mean risk priorities and their standard deviation were initially calculated in SPSS to establish the confidence interval.The results indicated that risks scoring above 37.72 would be classified as high, risks scoring below 30.73 would be classified as low, and risks falling between these two values would be considered moderate.Based on this classification, control plans and mitigation measures were initially developed for highlevel (H) risks in order to reduce them to moderate-level (M) and low-level (L) risks.Subsequently, control plans were designed for moderate-level (M) risks with the objective of reducing them to low-level (L) risks through the implementation of control methods and continuous monitoring.
As Table 6 demonstrates, 67% of the risks in life cycle operations were at low levels while 33% were at high levels.As Table 7 demonstrates, 75% of the risks in control room operators were at low levels while 25% were at high levels.
As Table 8 demonstrates, 64% of the risks in sit staff activities were at low levels while 29% were at high levels.
As Table 9 demonstrates, 75% of the risks in repairs were at low levels while 25% were at high levels.
Analysis of occupational safety during repair operations identified the primary occupational hazards, encompassing risks associated with lifting heavy components, chemical spills, falls from elevated areas, electrical hazards, cable damage, personnel falls, and inadequate use of personal protective equipment.These findings align with similar studies. 7,30,33Loss and damage encompass broad concepts that can be defined from various perspectives.Each industrial unit faces diverse hazards and unique damages influenced by its processes, operational conditions, materials, equipment, personnel, location, urbanization geography, and other parameters.The hydrocracker unit at the Abadan oil refinery experiences the highest operational pressure among all units.Hydrocarbon cracking in the presence of hydrogen demands exceptionally high pressure due to the nature of the hydrocracking process.Operating under such pressure is highly sensitive, significantly increasing the risk of leaks.The operational sensitivity is particularly heightened at this pressure, coupled with extremely high temperatures and the presence of hydrogen, placing this unit in a distinctive position in terms of operational considerations.
Activities performed in the hydrocracker unit at the Abadan oil refinement plant include the life cycle operation, control room operators, site staff activities, and hydrocracker unit repairs.In the life cycle, hydrogen gas and feed mix and enter the catalyst reactor after being heated up and reaching the desired temperature for reaction, where desulfurization, denitrogenation, and hydrocracking reactions occur in contact with catalysts (alumina-silica-based catalyst with molybdenum and nickel metals) present in this unit.After passing through the reactor and undergoing the mentioned reactions, inlet feed enters the separation tower where various products (crude gasoline, liquefied gas, kerosene, gas oil, and oil cut) are produced and separated.The catalyst in the unit is designed based on the primary product obtained in the unit and could be either amorphous or a molecular sieve.Hydrocracker unit environmental risk assessment using the EFMEA analysis The results indicated that 67% of the risks associated with the life cycle operation were low while 33% of them were high in terms of intensity.Also, 75% of the risks associated with control room operators were low and 25% were low in terms of intensity.Moreover, 64%, 7%, and 29% of the risks associated with the activities of site employees were low, moderate, and high in terms of intensity, while the corresponding figures were 14%, 29, and 57% in the case of risks associated with repairs, respectively, which is consistent with other studies. 15,33he occurrence of accidents in technological systems and industrial facilities highlights the significance of continuous progress in safety research, encompassing safety standards, modification of safety evaluation methods, and identification and evaluation of the role of factors involved in safety.Managers of industrial facilities and technological systems typically aim to identify the factors that led to an incident after it occurs.Managers of industrial facilities and technological systems typically aim to identify the factors that led to an incident after it occurs. 34,35As a result, the study and identification of risk factors, along with their prioritization, play a prominent role in this industry.

Conclusion
The present study aimed to identify and evaluate risks associated with various activities through occupational safety analysis.Risk levels were calculated based on

Table 1 .
Risk Evaluation of the Activities Performed in Life Cycle Operations in the Abadan Refinery Plant's Hydrocracker Unit

Table 2 .
Risk evaluation of Control Room Operators in Abadan Refinery Plant's Hydrocracker Unit

Table 3 .
Risk Evaluation of Site Staff Activities in the Abadan Refinery Plant's Hydrocracker Unit

Table 4 .
Risk evaluation of maintenance in the Abadan refinery plant's hydrocracker unit

Table 5 .
Safety, Health, and Environment Risk Indices in the Hydrocracker Unit of the Abadan Oil Refinement Plant

Table 6 .
Risk Levels of Life Cycle Operations

Table 7 .
Risk Levels of Control Room Operators

Table 8 .
Risk Levels of Site Staff Activities identification of causes for safety, health, and environmental risk levels in the hydrocracker unit at the Abadan oil refinery.Occupational safety analysis of life cycle operations revealed tangible hazards, including gas leaks in gas pipe flanges and risks of fire and explosions.Control room operators faced safety risks such as technical failures in alarms, hindering their transmission to the control room.Site staff activities posed risks such as contact with noise and particles, slipping on surfaces with spilled substances, falling from heights, and more.Moreover, the ranking of risks in life cycle operations highlighted gasket failure, valve control failure, and path (pipe) perforation as the highest risk priorities.Similarly, technical failure in alarms ranked highest among risks for control room operators.The ranking of risks in site staff and repair activities in the hydrocracker unit of the Abadan oil refinement plant indicated potential issues, with the sentence incomplete and requiring additional information.

Table 9 .
Risk Levels of Repairs Injury to the spine Not working for a long time in one mode, rotating shift work if possible Providing and equipping work environments with the risk of falling from a height with appropriate protective equipment, holding long-term and short-term training (TBM) before starting work