Recently Obtained Project Best Practices Guidelines for the Management of Pressure Parts in a Power Plant

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ETD is pleased to announce another triumphant achievement with guidelines for the Management of Pressure Parts in a Power Plant for a North African based plant.

The client has a program to develop a best practice manual for the management of pressure parts in a power plant. The thermal power plant is comprised of many high temperature and high-pressure components that are a critical part of the power generating cycle. These systems are susceptible to damage if not operated and maintained properly. Failure of these components is usually very catastrophic and could pose a risk to human life as well as incurring major downtime of a facility and associated costs of lost production. In most jurisdictions these systems are governed by regulatory bodies in order to ensure that they are maintained to a standard.

As ETD have carried out various practical review and survey type projects on risk assessment, condition assessment, life assessment and cost analysis studies including review of clients’ data on cost issues, risk events, maintenance programs, reliability and availability of plants, fleet wise comparison/benchmarking of plant performance for European, USA and Asian utilities, etc. Therefore ETD were asked to prepare a best practices document that identifies various pressure components in a boiler/ HRSG, describes the damage that can occur to them both under base-load and flexible operating conditions, the existing inspection and monitoring techniques, the development of new and more recent innovative techniques, repair practices and strategies and how to use all of these techniques to keep pressure parts in good condition and operate a power plant efficiently and at an optimum cost. This document included a management framework to ensure that all parts are being operated and maintained according to established standards in the industry and meet all the regulatory requirements. ETD have also carried out comprehensive reviews of related areas such as ‘on-line monitoring tools’, ‘developments in risk-based maintenance programs and inspection techniques’, ‘guidelines for CCGT/HRSG lifing and risk-based approaches’, ‘plant cycling (both conventional and CCGTs/ HRSGs)’, damage due to cyclic operation and risk-based inspection, power plant component replacement strategies and technical and financial risks, etc. Through its Group Sponsored Projects (GSPs) ETD has developed new and more sophisticated techniques for power plant inspection and these have included the development of the portable Scanning Force Microscope (SFM), Electrical Discharge Sampling Equipment (EDSE) - a spark erosion device for ‘boat sampling’, and its precision portable hardness tester known as the ‘Smart Sleeve’.

The document will explain the different challenges with respect to fired and non-fired boilers and describe the importance of burner adjustment to avoid flame impingement. It will cover the degradation mechanisms affecting the materials and the degradation rate. The understanding of these factors can lead to appropriate re-inspection intervals and to the establishment of effective inspection methods.

Both time-dependent and time-independent degradation mechanisms will be discussed. Waterside and fireside corrosion, flow assisted corrosion, the performance of different alloys in boilers and steam pipework, preservation while off-line, why when and how to chemically clean pressure parts, inspection, testing and record keeping procedures, keeping the steam turbine and condensers in good order, feed heaters, boiler feed pumps boiler chemistry and blowdown, steam blowing, efficiency checks, pressure tests will be discussed. Alternative methods to hydro testing, such as detailed NDE using new state-of-the-art NDE techniques, will be discussed to help limit the damage to pressure components in old plants. In terms of component preservation both dry and wet preservation techniques for long and short-term preservation will be discussed and guidelines provided.

The maintenance philosophy/ strategy should be based on the belief that it is possible to avoid unwanted equipment failures and unnecessary maintenance activities through appropriate application of various techniques supported by proven processes and procedures carried out by well-managed and competent personnel. To ensure maintenance management can achieve the business objectives such as plant availability and reliability targets, maintenance performance needs to be reported and monitored. This would then be used as input for initiating the improvement cycle. This improvement program will trigger revision of the maintenance strategies and/or change in the way utilities operate the plant. This is performed continuously to ensure that any operator can deliver what is expected by the owner.

The outcome of this project will be a manual for the management of pressure parts of power plant. This manual will offer a practical guide as to how the integrity of boiler / HRSG pressure parts is managed with emphasis on the best practices.

This study will help the participants to understand how a successful pressure part management program can deliver benefits related to better informed strategic decisions, increased operational efficiency, safety and integrity of the equipment.

For more information on our guidelines & reports, please click here.

Recent Completed Project on 'On-Site Inspection and Remaining Life Assessment of a Boiler' for a European Power Plant

ETD is pleased to announce the successful recent completion of a remaining life assessment project.

A European based power plant approached ETD to submit a proposal on Remaining Life Assessment (RLA) of one of their boilers. The work involved performing on-site inspections - ultrasonic thickness measurements (UT) of tubes (wall thickness & bore oxide scale), replication, hardness measurements of selected components from FSOH and ROH. The inspection data was then used to estimate tube metal temperature and identify material degradation which could then be used for damage assessment and predicting the remaining life of outlet headers and tubes of final superheater & reheater.

The scope of the work included:

  1. Reviewing the drawings of FSOH & ROH, tube banks of the boiler to be studied and identify accessible test locations for on-site inspections;
  2. Performing on-site ultrasonic thickness (UT) measurements of tube wall thickness and bore oxide scale considering ~40% of total tubes for FSOH & for ROH;
  3. Performing on-site replication and hardness measurements on straight tubes, T-piece nozzle weldments, stub tube weldments and hot reheat pipe weldment for FSOH & ROH;
  4. Assessment of all replicas by using OM (optical microscope) and to confirm the damage condition, further assessment of selected P/T/F91 & T23 replicas by using SEM (Scanning Electron Microscope) and if necessary, to confirm the damage condition, further assessment of selected P/T/F91 replicas by using ETD’s SFM (Scanning Force Microscope) at ETD lab;
  5. Assessment of damage and material degradation of outlet headers, tubes, T-piece nozzle weldments, stub tube weldments and hot reheat pipe weldments for FSOH & ROH based on the replication and hardness measurements data;
  6. Review & interpretation of UT inspection data and estimation of wall thickness loss & tube metal temperature;
  7. Assessment of the remaining life of FSOH & ROH components based on estimated tube metal temperature and other inspection data;
  8. Review & analysis of previous failures, inspection and maintenance data for other pressure parts of the boiler to complete the life assessment study;
  9. Preparing a full report including results of on-site inspections, analysis results of damage & life assessment study and make recommendations for any further actions to be taken for safe and reliable operation of the boiler.

 For more information on our remaining life assessment services, please click here.