New maintenance strategy delivers many benefits

Using proven methodologies, specialist companies can now help process industry companies achieve optimized asset management by reducing time, money and manpower for repairs and maintenance. One example is the biggest oil refinery in Bulgaria.

Many industrial companies want to reduce time, money and manpower for repairs and maintenance, but don’t want to jeopardize equipment reliability and safety or endanger the environment. For many companies, it is a complex task, requiring experience and expertise that they do not possess in-house. They need help from an outside specialist company.

One example is the situation at the biggest refinery in Bulgaria. This company has an annual capacity of seven million tonnes of crude oil – more than 140,000 barrels a day.

Despite its undoubted success, the refinery has a 10-year plan that includes several programs to improve performance. One of the programs will sound familiar: They want to improve reliability, safety, health and environmental issues while at the same time lowering maintenance and repair costs.

Lacking the specialist expertise
Knowing they lacked the special expertise to develop a maintenance strategy with such seemingly contradictory objectives, the refinery management invited proposals from two companies with experience in the field. They asked the companies to put forward ideas for a limited-scale pilot operation for planning and implementing a maintenance strategy on one of the refinery’s four atmospheric distillation units. They compared the two proposals and then chose SKF Bulgaria as the company to carry through the pilot project.

SKF Bulgaria’s proposal was to combine a Reliability-Centered Maintenance study, using SKF’s proprietary SRCM analysis process, together with a risk-based inspection (RBI) study. The objective for the analysis process was to develop an optimized reliability-based maintenance strategy while the inspection study was risk-based, focusing on mechanical integrity.

One of the factors which led to the selection of SKF Bulgaria was its suggestion to begin with a pilot project. This called for fewer resources from the refinery by focusing on SRCM, which specifically reduces the resource requirements originally associated with classical RCM studies.

Functionality-based methodology
SRCM is a logical, functionality-based methodology used to evaluate and optimize a maintenance program. It is applicable to any facility in a wide range of industries, such as electric power (nuclear, fossil, hydro), petrochemical, oil refineries, pulp and paper, manufacturing, biotech-pharmaceutical and other processes.

During the evaluation, step-by-step considerations are made of the functions integral to the operation of a system or unit. This includes the mechanisms of failure for each of these functions; the effects of failure; and the selection of applicable and effective maintenance tasks to address the identified failures.

The overall aim is to develop a maintenance program based on system functionality that will enhance system reliability and availability; make optimum use of available maintenance resources; and provide adequate documentation for additions and/or revisions to existing maintenance programs.

Primary benefits include:

  • the concentration of maintenance resources where they will do the most good;
  • the application of a least-cost strategy;
  • the elimination of unnecessary maintenance tasks;
  • finding the simplest and most cost-effective means of maintaining equipment or testing for degradation;
  • the development of a documented basis for the maintenance program; and,
  • full utilization of maintenance personnel and contractor experience when determining proactive maintenance (PM) tasks and frequencies.

Core team training
Introducing the SRCM process into any plant system entails a coordinated effort between plant personnel and the process analyst. The plant personnel are usually craft, engineering and operations personnel as well as those directly responsible for the project (the core team). To obtain the most thorough and accurate information about the system under analysis, the analyst must solicit input from these various sources.

Typically, the core team consists of personnel from engineering, operations, planning and maintenance (including supervisors foremen and craft personnel) who are empowered to make decisions and implement changes in the maintenance program (change existing preventive maintenance tasks, add new tasks, purchase predictive maintenance technology/equipment, etc.). The core team will also know who is an “expert” on particular systems and will ensure that these experts are present during analysis review sessions.

At the Bulgarian refinery, the pilot program began by introducing the core team of six refinery personnel to SRCM. Using presentations, meetings and on-site visits, it was explained how all equipment is not equally important and that SRCM concentrates on the reliability factor. It makes sure that the equipment most critical to the continuing operation of the plant receives the highest level of maintenance attention.

It was also explained to the core team that whereas SRCM considers all plant systems associated with the process and attempts to quantify all risks, the Risk-Based Inspection (RBI) is concerned primarily with pressure and containment systems such as vessels and boilers, pressurized and refrigerated storage tanks, compressors and pumps, with associated pipe work and valves. The main focus is on integrity and the lessening of risks associated with safety and the environment.

The RBI is done using a variety of inspection techniques such as visual inspection, penetration testing, magnetic particle inspection, eddy current, radiography, ultrasonic (for thickness and flaws), remote screening (thermography, ultrasound, pulsed eddy current), and specialist NDT technologies.

RBI also offers an opportunity to optimize the cost of achieving compliance with statutory obligations in terms of health and safety. This is achieved mainly through the use of a Tischuk OCA system (T-OCA). This computerized database applies a set of rules to each specific item. For the pilot study, T-OCA software was used to assess both the consequences and the probability of failure of the process equipment and piping. Bulgarian legal inspection requirements were built into the software, but it can be supplied to suit United States, United Kingdom, Australia, world and Gulf State oil producers.

The system also enables users to select from probability rule sets for oil and gas production, chemicals production or refining – with imperial or metric units.

Learning by doing
The team received further training on the theories and science related to the SRCM and RBI methodologies, then they were mentored and coached as they put their training into practical use (learning by doing).

Their first assignment was to consider and agree upon reliability criteria and acceptable risk levels for equipment and agreed process flows. They then considered system boundaries.

The second assignment for the core team was to identify and analyze the atmospheric distillation unit’s equipment to determine each item’s criticality and risk level.

With both assignments satisfactorily completed, the core team began work on the SRCM analysis and the Risk-Based Inspection. All work on the pilot operation was completed within three months and resulted in a maintenance strategy for the distillation unit. After approval from the refinery top management, it was put into operation.

Twelve months later, the feedback indicates that the results are in line with expectations.

One concern that is always connected with such “change” projects is how maintenance people will respond to the pilot program and the resulting maintenance strategy. After all, many have been doing the same job for 30 years and can understandably be reluctant to change. In such situations, it is typical for some to claim it would be impossible to implement. But the new system is in place and working well.

One of the reasons why things went so smoothly was the involvement of the refinery’s top management right from the start. Without strong support from the top, such projects become difficult if not impossible. The refinery top management commitment was strengthened by good communication and training. Everyone understood what was being done, why and how it would impact on their job.

Repeat job
Valeriy Konev, managing director of SKF Bulgaria, said, “The refinery was satisfied with the job we did, and we were asked to do a repeat job on three more units – the hydrodesulpharization unit 2, fluidized catalytic cracking unit section 200 and the catalytic reformer unit 1. Then, the refinery used their own team to carry out similar programs on a further 19 units. More recently, the refinery management created a central working group to coordinate and implement further studies using SKF methodologies in their remaining six refineries.”

This is good news for any process-industry based company seeking to improve performance and optimise asset management. With assistance from companies such as SKF and others, they can, using proven methodologies, successfully improve plant performance and be more profitable.

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