Gas Turbine Handbook : Principles and Practices

Case Study #2 259
replaced and cracks in the combustor were field repaired.
It is necessary to point out that the two machines operate in a
very polluted environment. Traces of the lead, zinc and natrium were
found in the gas turbine compressors during the Major Inspection.
Furthermore, ABB Field Service personnel have observed, on occasions,
that implosion doors of the air inlet plenums were found to
be opened by operators during the plant operation. The subsequent
metallurgical analysis of the damaged parts indicated that the rapid
and frequent change of fuel quality is also contributed to the damages
and cracks in the combustor.
The spare parts and maintenance cost of the two GT10 turbines
up to the first Major Inspection was US $140,000 for the two units
(for the first three years). For a total of 50,000 operating hours at a
combined output of 34,000 kW, this service cost comes to less than 0.2
mils/kWhr. The estimated total cost of parts and service of the Major
Inspection of Unit #2 was US $1,120,000; which is equivalent to 2.6
mils/kWhr.
Using the same payback calculation technique that was employed
in the Corinth Motor Oil Project, the payback of the refinery
cogen plant is estimated at 3.5 years. Figure 15-6 describes the plant
operating characteristics.
Figure 15-6. Hellenic Aspropyrgos Refinery Aspropyrgos, Greece.
GT10 Combi/cogen Operating Parameters
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Gas Turbine Units
2 × GT10, ABB STAL
Unit Output 17 MW @ 95°F
Fuels
Steam Turbine-Generator
HRSG
High Pres. Steam
Refinery Flare Gas/Propane/
Diesel Oil
15 MW, ABB Type WG1000
30 tons/hr @ 609 psia/770°F
Low Pres. Steam
65 tons/hr @ 55 psia/338°F
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