Bradley Lake Power Project (BLPP) Nozzle Refurbish

Transcription

1 Bradley Lake Power Project (BLPP) Nozzle Refurbish

2 Bradley Lake Unit Overview 2 FUJI generating units rated at 63 MW each

3 Overview Vertical shaft with a single turbine/runner

4 Overview Pelton wheel design runner

5 Overview 6 nozzles per unit (4 ft. x 6 ft.)

6 Overview 6 nozzles per unit 3 control modes Speed mode - all 6 nozzles function as a group Power mode - nozzles sequentially operate in pairs 2, 4, or 6 nozzles Divider mode system load rejection events the divider plates enter the water stream to deflect water flow until the nozzle position is reduced, (nozzles have a 90 second stroke time)

7 History 1992 Commercial Operation 2002 First nozzle refurbish due to intermittent sticking 2006 Major runner, divider, and governor control changes Replaced original cast runners with forged runners Replaced the governor with a SAT automation PLC Replaced the electro/hydraulic servos Added additional hydraulic accumulator storage Replaced the original water deflector plates with a modified divider plate design 2014 Governor PLC replaced with DCS system Second nozzle refurbish project initiated due to oil leakage from unit #2 nozzle #1 internal oil drain

8 Bradley Lake Nozzle Refurbish Plan Step 1 Replace nozzle 2-1 with the spare nozzle Tested and proved the functionality of the spare nozzle. Utilizing personnel that were involved in the 2002 and 2006 unit modifications, the spare nozzle was installed on unit #2 and the failed nozzle was dismantled to investigate the cause of the failure. Catalogued and numbered each O-ring, seal, bushing, and hard metal part.

9 Refurbish Plan Step 1 Replace nozzle 2-1 with the on site spare nozzle Step 2 Re-establish contact with the current FUJI authorized vendor. In the 10 years since the original nozzle refurbish, FUJI had undergone various mergers and changed their distributorship in North America.

10 Refurbish Plan Step 1 Replace nozzle 2-1 with the on site spare nozzle Step 2 Re-establish contact with FUJI who had undergone various mergers and changed their distributorship in North America Step 3 Locate parts and suppliers (4 categories) Hard parts, (nozzle tips, bushings, piston rings, etc.) Soft parts, (O-rings, gaskets, u-cup seals) Machine shop for piston rod refurbishment Shipping and transportation as Bradley Lake is not connected to the road system and is landing craft or air freight dependent (approximately 17 tide to dock a landing craft at Bradley Lake)

11 Main Nozzle Parts

12 Hard wearable parts Large tip / 32 mm hex Small nozzle tip Nozzle tip seat ring Eight bushings (3 to 18 ) Piston and rings

13 O-rings and seals 22 various O-rings range from 17 mm to 319 mm (.6 in to 12 in.) 4 large O-ring cords per nozzle U-cup seals range from 60 mm to 230 mm (3 to 9 )

14 Nozzle wear evaluation

15 O-Ring wear rolled and/or worn Oil side O-ring

16 Piston Rod Wear Sludge buildup Piston rod corrosion

17 Conclusions Actions Nozzle tips Seat rings Bushings Minor wear, still very serviceable Large tip / 32 mm hex Nozzle tip seat ring Eight bushings (3 to 18 )

18 Conclusions Actions Nozzle tips Seat rings Bushings Nozzle body Minor wear, still very serviceable Some corrosion and wear in areas where the coal tar coating had failed. Applied epoxy paint is various test areas.

19 Conclusions Actions Piston rod corrosion The damaged areas were repaired and sprayed with a High Velocity Oxygen Fuel (HVOF) spray. The spray material should improve corrosion resistance. Some of the sprayed areas were polished where needed on sealing surfaces and other areas were left rough where applicable.

20 Conclusions Actions O-rings The O-rings were replaced with standard OEM material Future considerations: Modern O-ring material options, resistant to rolling? Design options such as quadring etc. Addition of a second O-ring groove or backer ring

21 Conclusions Actions U-cup seals Original material was fabric impregnated NBR that is not widely used today. The larger metric seals were custom ordered to fit NBR material seals well but also wears (contributed to O-ring failure) Testing was conducted with Polyurethane AU 92A material. Wears better but is less forgiving in terms of fit. Variances in dimension tolerances.

22 Conclusions Actions Nozzle design Future considerations Are there better more modern designs? Refurbish expense vs. complete upgrade? Ease of serviceability in different design? Longer wear of seal parts?

23 Piston Shaft Surface Roughness Piston Rod Spec Sheet mm = in 90 mm = ID# Ø Ø Ra/Average A A A A A A B Surface Roughness Chart 2016 ID# Ø Ø Ra B B B B B Spare