August 2020

Special Focus: Valves, Pumps and Turbomachinery

Working together, MTBR can be improved

This article provides an overview of the actions carried out in recent years at Repsol’s Cartagena refinery in Spain to improve the mean time between repairs (MTBR) of the plant’s rotating equipment.

This article provides an overview of the actions carried out in recent years at Repsol’s Cartagena refinery in Spain to improve the mean time between repairs (MTBR) of the plant’s rotating equipment. MTBR is a key performance indicator (KPI) that enables refinery personnel to identify reliability improvements, along with opportunities for improvements to reduce rotating equipment failures.

MTBR evolution

The Cartagena refinery’s MTBR has increased 126% since 2012 (FIG. 1). The calculation of the indicator is carried out monthly for the entire refinery. Refining personnel separately calculate the MTBR of each type of equipment, such as centrifugal pumps, rotary pumps and reciprocating compressors. Likewise, this measure is completed at the level of each operational area, which allows refining personnel to calculate the MTBR by type of equipment in each area (FIG. 2).

FIG. 1. MTBR evolution at Repsol’s Cartagena refinery, 2012–2019.
FIG. 2. MTBR improvements in operating areas, 2012–2019.

At the beginning of each year, refining personnel set MTBR improvement objectives for each operational area, so that the monthly publication of the results allows personnel to evaluate the actions implemented or pending to achieve the proposed objectives.

Having multidisciplinary teams involved in improving reliability in operational areas has enabled personnel to improve the MTBR in all sectors, regardless of the age of the plant, severity of the process, etc. Other metrics enable personnel to assess the evolution of the plant’s MTBR. These include:

  • Maintenance costs
  • Reduction of urgent maintenance work orders
  • High availability of process and utilities plants.

Reliability Improvement Project

In 2014, Repsol’s Reliability Improvement Project was implemented as a process of cultural change, focusing on the systematic analysis of the most important failures. It applied root cause analysis (RCA) techniques, which led to a reduction of failures and maintenance costs. This project has been implemented in all five Repsol refineries in Spain (FIG. 3).

FIG. 3. Repsol’s Reliability Improvement Project was implemented at all five of its refineries in Spain.

Cells by each operating area were given the objective of reducing breakdowns and maintenance costs. Each operational area is defined with a matrix that considers the risk of the failures and the costs, among other variables, classifying the reliability cases from greater to lesser importance. Several cases are studied each year. The analysis teams are defined, and a schedule is made to address the analysis cases.

Having multidisciplinary teams in the analysis of RCAs allows refining personnel to have crucial details of the maintenance interventions and the operation of the facilities—enabling analysts to fully understand the events, and knowledgeable technicians to implement the modifications. This system has enabled refining personnel to perform approximately 30 RCAs/yr related to dynamic equipment.

Operational incidents (such as load drops to units or unexpected stops to operations), along with annual “bad actor” equipment reports, help teams to determine equipment that should be analyzed in the RCAs. For bad actors, these analyses are prioritized by the number of failures and the costs involved.

The identification and resolution of the root causes identified in the RCAs reach different types of actions and areas. For example:

  • Operations: Best practices, procedures, modifications
  • Maintenance: Preventive, predictive, procedures, lessons learned
  • Investments through change management that ensure the suitability of the proposed modifications.

Additional improvement actions

Following are additional improvement actions that have been taken.

Mechanical seal reliability contracts. The purpose of mechanical seal reliability contracts is to improve the reliability of the equipment, the safety of the facilities, the optimization of the inventory, and the reduction of the operational and maintenance costs.

To achieve these objectives, a working team must be established between the plant technicians and the mechanical seal manufacturer that will work toward the common objective of reducing faults. The main actions carried out with these contracts include:

  • Implementation of preventive routes for the operation of sealing systems
  • Training operations and maintenance personnel
  • Comprehensive analyses of all failures and improvement proposals
  • Realization of RCAs, with the participation of the mechanical seal manufacturer
  • Monthly monitoring reports.

Since 2014, mechanical seal reliability contracts have improved the plant’s MTBR by 46% (FIG. 4).

FIG. 4. MTBR improvement of mechanical seals, 2014–2019.

Lubrication. Undoubtedly, good management of lubricating oils—from storage to use—resulted in a reduction of lubrication failures. Over the past several years, various actions were developed to increase better management of lubricating oil in the plant. The first was to rationalize the number of oils used in the facilities. This prevents contamination or incorrect use.

For prevention, the Cartagena refinery has an oil sample analysis program that enables personnel to monitor the condition of the lubricating oil to ensure that it is in good working condition.

For storing lubricating oils, closed booths allow personnel to avoid contamination of the porta-feed and drums, as well as the degradation of the oils. The oil filler elements of bearings and bearing supports are standardized containers where, by means of a color code, operators know which container to use for each equipment, avoiding contamination due to the mixing of lubricating oils.

The refinery also has portable oil purifiers and portable filtering equipment for recovering oils that are in service, so there is no need to stop the equipment, which benefits availability.

Other improvement actions. Digitization is providing the refinery with improvements in various fields. These include:

  • Use of digital equipment on operator routes, which allows for efficient documentation of equipment operations
  • Wireless monitoring of equipment for early diagnoses of monitored parameters (e.g., vibrations and temperature).

Additional digital solutions integration with rotating equipment will result in greater reliability.

Operational and maintenance training, along with reliability, are necessary to help mitigate equipment breakdowns. Therefore, Repsol has trained its maintenance and reliability personnel in lubrication and vibration analysis and has trained its operations personnel in lubrication and mechanical seals. The rationalization, and continuous review, of preventive maintenance plans—in a fixed time and according to condition—must also be done to contribute to the reduction of equipment failures.

Takeaways

The MTBR is an indicator used to measure the reliability of the Cartagena refinery’s rotating equipment. The positive evolution means that the refinery has cut failures in half since 2012; there are fewer incidents in the plant caused by rotating equipment failures, and maintenance costs have decreased because of fewer breakdowns. These results are due to the work of the entire refinery team:

  • Operations: Monitoring equipment in service, detecting anomalies and correcting them—or notifying the reliability department, training personnel and using digital tools to report failures
  • Rotating equipment maintenance: Repairing equipment, training personnel and executing the fixed-time preventive maintenance plan
  • Rotating equipment reliability: Defining and reviewing preventive maintenance plans, training personnel and making decisions according to the condition of the equipment
  • Utilization of RCA studies to analyze the root causes of equipment failures.

In the coming years, Repsol expects its plants’ MTBR to continue to improve due to the introduction and consolidation of new digital tools—and the systematic implementation of the solutions identified in the RCAs, along with good management of lubrication and mechanical seal programs and operational and maintenance best practices. HP

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