First Time in the Kingdom of Saudi Arabia – Removing of Gas Turbine Rotor of GE-7001E as One-Piece

 Shedgum Power Plant is the largest combustion gas generating facility of SEC-ERB. This plant consists of 9 Westinghouse Model W-501D and 8 General Electric Frame-7001E units. The total plant capacity at ISO is 1,338 MW .

The only technique known to SEC-ERB to remove the complete GE-7001E gas turbine rotor was by decoupling the turbine and compressor sections and drag them separately. This is the only procedure approved by the manufacturer, which leads to a special alignment during the assembly stage.   This alignment takes about one week and highly skilled technicians are required.

 A committee consists of Shedgum Plant Engineers and  T&I Team was established to study and improve the process to come up with a new process ensuring quality, time and cost. The main challenge was to achieve quality with low cost and less time The committee finds out that removing turbine-compressor rotor, as one segment will save a lot. Saving includes time in unit outage and cost of skilled manpower (no alignment is required). This issue was discussed with the GE, the Manufacturer of the Gas Turbine but they report that such practice never adopted before and have no written and approved procedure to remove the rotor as complete. Moreover, they request to send their representative for technical support, which will cost about SR 100, 000.

Then the issue was discussed internal between plant maintenance and engineering and the decision was to adopt the new procedure by plant personnel only with the support of plant and GD management. The old technique known in Saudi Arabia is to remove the complete Gas turbine rotor (GE-7001E) by decoupling the turbine and compressor sections and drag them separately.  But, during the Major Overhaul of Shedgum unit 14 (GE-7001E) that was carried out on 2001 T&I, the new technique was adopted and the rotor had been removed as complete rotor (one piece).

The total  capacity of the carne which was used during rotor  lifting    was 300 tones which was calculated based on the total rotor assembly wight and  the height which was supposed to be  reached with considering all safety factor required . Moreover all dimension  and clearances were determined to allow safe vertical lifting  .

 The rotor was lifted in three locations using special sling wires. Due to the small clearances  between rotor blades and stationary blades in the bottom half casing, special guides were used during  lifting-up. These special guides were fabricated in house from carbon steel. All the process tasks were closely directed by T&I engineer to ensure implementation of the new procedure. It was a challenge by Generation Department to take this opportunity with all risk involving in this work and it had been done successfully.

Abdulhaq A. Al-Khars

Senior Engineer

Generation Department

Eastern Region Branch

Saudi Electricity Company