|This article is part 2 of a 2-part series.|
|Part 1 | Part 2|
This series of articles describes the elements for a successful fixed equipment reliability program in a petrochemical facility. These articles will address management systems, engineering practices, preventive/predictive maintenance/inspection systems, performance metrics, and resources. The fixed equipment reliability program at Lyondell Chemical Company and a number of best practices developed as part of the reliability program will serve as much of the basis. Some success stories and lessons learned are shared.
A model fixed equipment reliability program is included in this article and can be used to evaluate the reliability program at any site. A list of abbreviations used in this article can be found at the bottom.
This article will pick up where the last one ended. As a refresher, Part 1 of this series covered:
- Management Systems
- Reliability Beliefs and Principles
- Performance Standards
- Inspection and Maintenance Standards
- Inspection and Maintenance Procedures
- Key Performance Indicators (KPIs)
- Compliance Audits
- Engineering Practices
- Engineering Standards
- Engineering Data Management
- Reliability Practices
- Inspection Management
On to Part 2 and the conclusion of Fixed Equipment Reliability Assuring Excellence.
A unit experienced a major leak in a column due to internal corrosion. The incident investigation indicated that a process change was documented and approved through the management of change (MOC) process. RBI analysis did not predict the leak and suggested inspection 10 years from now. What happened? The investigation further indicated that inspection personnel was not included in the MOC approval process; therefore, the RBI analysis was not updated with the higher corrosion rate expected from the change in the process.
It is critical to the success of a mechanical integrity program that operations, process, and maintenance personnel understand the inspection activities and work processes. At best-in-class facilities, the applicable MOC forms are routed through the inspection department for review, approval, and updating of inspection planning tools. Operators are trained on mechanical integrity critical variables. When these critical variables are exceeded, inspection personnel are notified, an investigation is performed and an action plan is developed.
Some other examples where operations activities and work processes can greatly enhance fixed equipment reliability are:
- Integrating the routine visual inspection of equipment and piping into operators’ rounds. Use of operators as first-line inspectors greatly enhances the inspection program. An example is a visual inspection of insulation for damage to jacket and caulking. This activity helps avoid CUI by maintaining insulation integrity.
- Maintaining cooling water quality and back flushing cooling water exchangers. This will have a significant positive impact on heat exchanger tube bundle reliability.
- Reporting all pressure boundary leaks irrespective of leak rate. Inspection personnel must be notified whenever there is a leak of any degree.
An exchanger leaked within a few months after a turnaround. This exchanger was retubed during the turnaround. Tube metallurgy was upgraded from carbon steel to duplex stainless steel (SS), and tube-to-tube sheet joints were welded to prevent leaks to the shell side. An investigation indicated that the tube-to-tube sheet welds had cracked. Engineering standards, which normally would be used for procuring new exchangers, had not been applied to this work. This omission resulted in the weld procedure for duplex SS to carbon steel weld not having been reviewed. Also, NDE requirements for the welds had not been specified.