Nigeria Ogun Project launches expanded medium repair for GT8


On July 22, 2019, Nigeria Ogun Project held the kick-off meeting of the GT8’s expanded medium repair, which means that the HGPI (Hot Gas Path Inspection) jobs of GT8 was started.
Up to the maintenance outage, the GT8 had been operating for 40,663.6 hours, and it tripped 72 times and was started 565 times. Through the BSI, it was found that there was serious cracking and ablation in the first-order double-pass flow passage; there was a crack at the joint between the outlet edge of the secondary nozzle and the root of the outer wall. Among them, combustion and hot aisle components have seriously exceeded the GE standard hot runner component repair and replacement cycle, so the project’s O&M team coordinated all the parties to actively prepare for the GT8 HGPI work.
As the key job of the project in 2019, the repair mainly includes the replacement of turbine first, second and third stage nozzles, moving blades, complex rings and all combustion parts, turbine and generator’s link brass checking, the exhaust silencer sunken and reinforced. The maintenance work range is enlarged compared with the GT7, and the replacement parts are all using GE upgrade parts. Replacing the second and third stage moving blades and the double ring without taking out the rotor, disassembly and assembly and clearance adjustment are the new challenges due to the small operation space.
In order to ensure the completion of the GT8 maintenance task within the 30-day planned period, the project set up a maintenance team led by the project leaders, and established six professional teams for safety supervision, quality management, mechanical, electrical, I&C and operation and a logistics support team to clearly and carefully deploy all the jobs and to overcome various difficulties caused by the rainy season, improve the quality of maintenance and work efficiency in all aspects.
The Production Department organized the mechanical personnel to make the HSE Program for the GT8 Hot Gas Path Inspection and passed the review of the technical departments of the headquarters; the project coordination meeting was held with the owner to communicate and coordinate the maintenance process and related matters; according to the HGPI maintenance standardization process developed at the beginning of the year, revise and improve the overhaul process and check the preparation works, which built foundation for insuring all the parts of the repair jobs.
Next, the Nigeria Ogun O&M team will strictly follow the repair plan to carry out the jobs and try to completed maintenance tasks on time with high quality and ensure that the unit can be put into operation as soon as possible.