Retrofitting – When Steam Turbines Age

Steam-Turbine
Steam-Turbine

Statistics show that as a power plant reaches its rated lifetime, the number of its forced outages begins to grow substantially, and its reliability and availability fall.

Simultaneously, in the operation process the turbine’s efficiency lowers more and more, even though it is partially restored at overhauls.

It is possible to find steam turbines that have successfully operated for 40 – 50 years or more. Lately, power equipment lifetime extension has substantially gained in its scope and acquired much more serious significance.

Steam turbine performance can degrade with time due to such factors as higher seal clearances, increased surface roughness in the steam path, WDE, and so on. But just replacing old components with their spares may not be enough to prolong its operation for at least another ten years. Nozzle and bucket aerodynamic-profile losses, secondary-flow losses, and leakage losses account for roughly 80-to-90 percent of the total stage losses.

In order to ensure high-efficiency turbine designs without sacrificing turbine reliability, it is necessary to use both highly-efficient nozzle and bucket designs to minimize profile and secondary losses, and advanced clearance controls to minimize leakage flows.

If you’re interested in learning more about advanced 3D blade design or upgrading steam turbines, you can view a recent recording in our User Center and sign up for our upcoming webinar, “Is It Feasible To Upgrade My Steam Turbines?” scheduled for February 12, 2014.

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