Lessons learned during a 7FA.03 CI/Package 3 upgrade

When owner/operators participating in the 7F Users Group’s 2014 Conference were polled using the organization’s new wireless audience response system, more than one-quarter of the attendees said they had responsibilities tied to 7FA.03 engines—many of those with the OEM’s so-called Package 3 compressor enhancement.

The Package 3 can take from two to four weeks to complete and involves the following compressor upgrades, in broad general terms:

  • Optimum-start feature assures IGV position is not conducive to R0 excitation.

  • IGV mods are designed to reduce R0 excitation.

  • R0 mods improve damage tolerance and reduce blade and edge-of-contact stress.

  • S0-S5 mods reduce FOD risk, maintain airfoil dampening, reduce airfoil stress, and improve damage tolerance.

  • S6-S8 mods to improve tolerance to damage are optional.

One user presented on his plant’s experience implementing two Package 3 upgrades, combined with combustion inspections (CIs), on dual-fuel, simple-cycle engines. He shared lessons learned with his colleagues, beginning with the recommendation to insist on a pre-outage meeting with the OEM at least two to three months prior to commencement of work.

It’s important to define roles and responsibilities during this meeting, the speaker said. Plus, it is in your best interest to create a single point of contact with GE, he continued, because it avoids having multiple groups competing for resources. Safety expectations and required documentation should be part of the discussion; so should the format and time for daily status update meetings.

Pre-outage lessons-learned checklist

  • Borescope the compressor and combustion sections, at a minimum, to identify any additional parts or spares that may be necessary.

  • Water wash the compressor to both facilitate blade mapping and possibly make it easier to free-up ring segments in S0-S4.

  • Mark rotation of all motors prior to disassembly.

  • Metal-stamp or mark the top and bottom of the IGV actuator arm, including the end yokes.

  • Measure and record the center of the lower IGV actuator pin to the base plate for use as a reference point during reassembly.

  • Measure and record total IGV actuator stroke.

  • Tape over the holes in the floor of the inlet plenum.

  • Inspect and document the condition of all flexible metal hoses.

  • Inspect and document all flange conditions (tightness, square, etc).

 Lock-out/tag-out checklist

  • Do not tag out the main air isolation valve because you will need air to adjust the ninth- and 13th-stage compressor bleed air valves. Instead, tag out the valve protecting the liquid-fuel atomizing air compressor.

  • Do not tag out the inlet valve for the water-injection skid because you will need demin water for quenching blade segments; do not use tap water. Instead, tag out the water exit valve serving the skid.

  • Do not tag/lock the IGV arm. The plates will be removed during the outage.

  • LOTO the turbine-compartment heat detectors with the main outage.

  • Have the IGV pin on the lube-oil lock-out.

 Outage lessons learned

  • Remove piping and obstructions and install scaffolding prior to breaking the compressor horizontal joint. This helps reduce the possibility of an accident when the casing is unbolted.

  • Request blade mapping be completed as soon as is reasonable after the compressor case comes off; witness same.

  • Prevent wood from being used to hammer on ring segments. Wood chips from such activities fall to the bottom of the compressor case and can create problems on restart. Good housekeeping in and around an open compressor is necessary to prevent self-inflicted issues.

  • Remove all clamps from bearing instrument wiring when disconnecting same.

  • Readjust the lower setting on plant air compressors to ensure they start at 100 psig. Technicians will need a large amount of high-pressure air when cutting blades and drilling load dams.

  • Mark Bently probes (thrust and radial pickups) before removing bearing caps.

  • Ensure CPD sensors are calibrated; they must be extremely accurate for starts on liquid fuel.

  • Remove extraction piping from the compressor case instead of at flange breaks.

  • Make sure scaffolding is secured and provide a swinging gate for access to the sides of the compressor case.

  • Mark and stage removed components in an area that will not lead to congestion. This can be challenging between units at a multi-unit site.

  • QA/QC is extremely important. Insist on documentation and have plant personnel assigned to witness all QA/QC activities. The speaker reported that four blade segments fell to the ground when lifting the upper half for one of his plant’s compressor cases.

  • Assign plant personnel to continually monitor site activities during an outage. If something doesn’t seem right, stop the job and get an explanation. The upper casing for one of the subject units was cut when removing old airfoils.

  • The lift-oil line mod described in Technical Information Letter 1582-R2 also was completed during the compressor enhancement/CI outage. When preparing for this work, be sure all of the parts identified in the TIL are ordered—not just hoses and clamps. Two additional tips: a mechanical tubing bender is essential; it’s important to adhere to the tubing routing plan described in the TIL.

  • Develop thorough rigging and lift plans for all components requiring removal.

  • Regarding IGV settings, keep an engineer or blade technician on-site until this adjustment is finalized.

  • QA/QC the IGV angles on all blades with a protractor as final adjustments are made when the IGVs are re-pinned during installation. CCJ