Page 472 - Practical Machinery Management for Process Plants Major Process Equipment Maintenance and Repair

Gas Turbines 449

3. Machine failures have been reduced drastically, with only one gas
turbine operating failure in eight years. This failure was caused by
operator error-the operator didn’t believe the instrumentation.
4. Component life has been extended by carefbl inspection, metal-
lurgical analysis, rewelding, and heat-treating.

Spare ParWSpeclal Tools

A maintenance policy for gas turbines must address the level of spare
parts required to achieve the reliability and availability objectives of the
user organization. There is no absolute guide to the purchasing of these
parts. The OEM will normally recommend a list of spare parts or in
some cases a number of lists such as commissioning spares, norm1 oper-
ating spares, major replacement spares, and in some cases contingency
spares. In certain instances users have been known to purchase entire en-
gines as spares, depending on the design, number, and critical nature of
the units.
A typical recommended spare parts list for a two-shaft, simple cycle
industrial turbine is shown in Table 9-1. This list does not include any of the
bolting materials which will certainly be required on any major overhaul or
the spare parts required for the control system.

~~ ~
Table 9-1
Typical Recommended Spare Parts List for Industrial Gas Turbines
Item Quantitv DescriDtion
1 1 Set of gas turbine and auxiliary gearbox bearing
shoes and gas turbine thrust plate and thrust bear-
ing pads.
2 1 Set of primary combustor baskets
3 1 Set of secondary combustor bask-
4 1 Set of combustor swirl plates
4 1 Set of fuel nozzles
J
6 1 Set of cross flame tubes and clamps
7 2 Flexible fuel gas hoses
8 1 Set of gas turbine thermocouples
9 1 Speed probe and extension cable
10 1 #2 Bearing vibration probe extension cable and
gland assembly and proximitor.
11 2 Sets of lube oil filter cartridges and gaskets
12 2 IgNtor plugs
13 1 Ignitor extension cable