Petro Vietnam’s Rapid Bearing Repair and Journal Machining
At Petro Vietnam Vung Ang 1 Thermal Power Plant, Mechanical Dynamics & Analysis (MD&A) experts repaired damaged babbitt bearings and refurbished journals for a customer on a steam turbine-generator with the unit in an assembled (rotor-in) condition.
The unit was forced from service due to turbine bearing failures. In a quick turnaround, journal refurbishment occurred in the field and was completed by MD&A Machining Services, while bearing repair occurred at MD&A Bearings Seals & Hydraulics Division in Euclid, Ohio, USA.
During the outage, bearings 1-8 along with the thrust bearing was removed and visually inspected to determine suitability for continued use. Bearings 3-6, all elliptical-type journal bearings, were found damaged and sent to MD&A (Ohio, USA) for repair. The bearings were refurbished using MD&A’s proven methods and final bore machining was completed after as machined journal dimensions were determined.
In addition to bearing repair, 8 journals were also restored. Journals 3-6 required machining and honing to remove minor radial grooving utilizing a stationary journal machine. Journals 1, 2, 7, and 8 only required polishing, which was also completed using stationary journal equipment. Because only polishing occurred, these journals had minimal stock removed and the customer continued to use the current size bearings as bearing clearances were well within specification. All journals met or exceeded the customer’s acceptance criteria.
Our team worked “in sync” with Petro Vietnam to fulfill all compliance requirements both in the USA and Vietnam to avoid any delay in transit and customs clearance. With all divisions working together, this team approach ensured the job was completed quickly and efficiently, minimizing the forced outage duration.
All incoming inspection data was provided to the customer daily along with an updated report. Inspection data consisted of axial journal measurements and concentricity checks. The same data was taken during the final inspection along with the addition of surface finish measurements.
Technical directors from MD&A provided oversight throughout reassembly and startup. During bearing reassembly, contact checks and clearance checks were performed.
Additional work completed during reassembly included:
- Coupling disassembly and alignment checks
- Alignment corrections by adjusting locations at bearings 1-6
- Alignment corrections by moving the generator assembly horizontally
- Disassembly of the thrust bearing to facilitate coupling disassembly
- Adjusting the position of the HP/IP turbine shell to match bearing moves at bearings 1 & 2
- Visual inspection and repairs of the thrust bearing pads and runner
- Final alignment checks and reassembly
- Oil flush utilizing on-base pumps
Our team quickly restored Petro Vietnam’s 8 journals and repaired 4 elliptical journal bearings, providing exceptional quality of workmanship and superior communication that met their expectations and exceeded the schedule.
MD&A experts are there when you need us! Providing comprehensive inspection and repair of turbine-generator components for many different OEMs across the world.
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