Gas Turbine Handbook : Principles and Practices

Hardware 23
Chapter 3
Hardware
Aero-derivative and industrial gas turbines have demonstrated
their suitability for heavy duty, continuous, base load operation
in power generation, pump and compressor applications.
While they share many similarities, there are times when
their differences make them uniquely more suitable for a specific
application. These differences are not always adequately considered
during the equipment selection phase. As a result operations and
maintenance personnel must deal with them throughout the plants
useful life. As shown in the previous chapter, schematically there are
little differences between the various types of gas turbines. However,
considering the actual hardware, primarily in the 20,000-horsepower
and above range, the differences are very significant.
SIMILARITIES AND DIFFERENCES 1
In spite of their common background, there are variations between
the aero-derivative and heavy industrial gas turbines. These
are weight, combustor design, turbine design, and bearing design
(including the lube-oil system). Grouping units in the same or similar
horsepower output range, the most obvious difference is in the physical
size of the heavy industrial compared to the aero-derivative gas
turbines (Figure 3-1 and 3-2). This physical size difference leads to
the comparisons in the following table.
The differences between the aero-derivatives and the hybrid industrial
gas turbines are less significant (Figure 3-3). Size, rotating
speed, air flow, and maintenance requirements are similar for both
type machines. The primary distinction is in the bearing selection
where the hybrids use hydrodynamic bearings (similar to the heavy
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