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GTG_1471GR_ABBGT851.doc

1 1977 ABB 11D5 (GT-851) 67Mw 60Hz DF Gas Turbine Generator With HRSG

Asking Price; US $5.5MM AS/ISPlus Removal Costs

DETAILS 

Gas Turbine: GT-851Original Mfg: Brown Boveri (ABB)Type: 11D4, Converted To 11D5Year Built: 1977S/N: 19251.24

Design Features:

* 17 Stage Compressor* Single Side-Silo Combustor* 5 Stage Turbine

* Cold End Drive* Firing Temperature 1836f* Turbine Row 5 Blades Are Laced

Rating: 67 MW @ 59FSpeed: 3600 RPMFuel Type: Natural Gas, (original burner also had option of liquid fuel)Burner: Coen Design Gas Burner Installed 1988, Rebuilt 1997 & 2000Control System: Tri-Sen PLC System

Generator: Manufacturer: Electric Machinery Rating: 85,000 KVA Voltage: 14.4 KvPoles: Two Cooling: Hydrogen CooledPF : 0.85 S/N: 175870005

Attached Heat Recovery Steam Generator (HRSG) tag B-701:

Foster Wheeler DesignYear Built: 1977

2 Pressure Boiler (1400 Psig And 45 Psig)C/W High Pressure SuperheaterC/W Natural Gas Duct FiringRated For 538 kpph @ 1400 psig, With A Superheater Temperature Of 880F

1.0 General Comments: July 12, 2002: OH: 187,819 hrs EOH: estimated at 197,659 (30 starts x 20

hrs added since Nov/2000)

Last Major Overhaul Aug 11, 2000: OH: 170,187 hrs, EOH: 179,427 hrs (note that the turbine was started back up in Nov/2000)

Total OH since last major overhaul in 2000: 17,632 hrs. Total EOH since last major overhaul in 2000: 18,232 hrs

Assuming GT ran continuously after start-up on July 19/02, the machine would reach the 24,000 OH in about 265 days (6,360 hrs), on or about May 1, 2003.

Spare parts listing on server as well as in ABB hard-copy books

Overhaul in 1997 saw all the turbine blades and vanes replaced. Last major overhaul in 2000. Blade/Vane sets that were removed for re-

conditioning are not available.

Has been running at reduced firing temperatures compared to the design of 1836F. Temp. control of 1750F calculated based on TAT which corresponds to a firing temp of about 1800F.

2.0 Summary of Component Status (more details as per Dow Overhaul Records):2.1 Blades/Vanes:

Turbine Row

Blades Vanes

1 New set in 2000. (Dow Req.#10956104, ABB quote 3176SQ)

24k hrs life, recondition for 2nd cycle

Have high temp erosion protection SS-14

New set in 2000. (Dow Req.#10956104, ABB quote 8522SQ)

24k hrs life, recondition for 2nd cycle

Have high temp erosion protection SS-14

2 New set in 2000. (Dow Req.#10956104, ABB quote 8522SQ)

24k hrs life, recondition for 2nd cycle

Have high temp erosion protection SS-14.

New set in 2000. (Dow Req.#10956104, ABB quote 8522SQ)

48k hrs life, recondition for another 24k cycle, recondition again for 24k cycle (Dow practice)

3 Re-conditioning set installed in 2000 (2nd cycle).

24k hrs life, recondition for 2nd and 3rd cycle

blades changed to 11N2 design

New set in 1997. Visual Inspection in 2000.

48k hrs life, recondition for another 24k cycle, recondition again for 24k cycle (Dow practice)

4 New set in 1997. Visual inspection in 2000

48k hrs life, recondition for another 24k cycle, recondition again for 24k cycle (Dow practice)

New set in 1997. Visual Inspection in 2000.

48k hrs life, recondition for another 24k cycle, recondition again for 24k cycle (Dow practice)

5 New set in 2000. (Dow Req.#109663244, ABB quote 8895SQ)

48k hrs life, recondition for another 24k cycle, recondition again for 24k cycle (Dow practice)

blades are laced (Dow practice)

New set in 1997. Visual Inspection in 2000.

48k hrs life, recondition for another 24k cycle, recondition again for 24k cycle, and another 24k cycle (Dow practice)

2.2 Inner U-Duct:

Alstom recommends 9 yr life (3 cycles), current one will have 18 yrs service by 2003. Some ‘elephant-skin’ surface defects present. Needs to be replaced in 2003.

Original U-Duct was large grain structure. Current U-Duct has fine grain structure (fine killed steel) and can last longer

Dow uses Les Engles, Engles Metallurgical Co., Minneapolis, to do metallurgical analysis of coupons cut out of U-Duct (2 circular plugs, 1” dia). Plugs are cut out of bottom, act as additional drain holes until plugs can be welded back in during a major

1999 – sent 2 plugs to Les – okay

2000 – U-Duct removed, re-conditioned by Major Tool in Indianapolis (thru Alstom), and re-installed. Re-condition means solution annealed, sandblast with special pure oxide grit, welds dye pen checked and repaired, then solution annealed again if required. About $300k USD.

Pins that hold duct in place are inconel 601 and are cut-out each time and replaced.

Monty Seal at lower combustor insert joint needs machining at each overhaul (20 spring-loaded pads)

inconel 617 material, about $830k USD to replace

2.3 Lower Combustor Insert:

Will have 18 yrs service by 2003. Severe ‘elephant-skin’ surface defects present. Needs to be replaced in 2003.

Re-conditioned in 2000 same as U-Duct and re-installed.

Inconel 617 material, about $375k USD to replace

2.4 Hot Gas Casing:

replaced in 1997 with a used one from Chugach Alaska (1 cycle already). Alstom recommends 9 yr life (3 cycles).

Re-conditioned in 2000 (same as U-Duct) and re-installed for 3rd cycle

Inconel 617 material, about $950k USD to replace.

Can re-condition again in 2003 for a 4th cycle if metallurgy is okay

2.5 Vane Carrier:

re-conditioned in 2000 by Alstom. (replaced any loss of metal, repaired pins for vanes)

Originally was 11D4 style – Alstom upgraded to 11D5 style (row 4 & 5).

In good shape – can last to 2009.

2.6 Metal Tile Carrier:

Weld repair every major overhaul – each tile support hook slot and tile supports are weld-repaired and ground out with pencil grinder (319 tiles, 8 hooks per tile). 4-5 weeks work, 2 shifts.

Tiles reconditioned each major overhaul - Liburdi re-conditions tiles (410 SS)

Could have spare set of tile carriers (support rings) for quicker overhaul. 5 Tile support rings 410 SS - $40k USD per ring.

Full set of tiles 410SS about $400k USD

2.7 Burner:

Special Coen design (5 cans). Only other similar burners are the 2 in Dow in Plaquemine, Louisiana (Dave Milner)

Precision Industries in Baton Rouge (sub for Coen) re-conditioned burner in 2000 and re-built it in 2001.

2.8 Rotor:

No indications of cracking or deterioration. Runs under base load (limited starts/stops). Has been exchanged with rotor from Louisiana at one point. Estimate 150,000 OH.

Would recommend taking replica samples at each stage to check grain structure (polish rotor and take metallurgical replica sample).

Henry L. Bernstein [gtma@texas.net], in San Antonio Texas can do analysis

Other:

Woods Group, Texas, can manufacture new blades and vanes.