

This paper will take into consideration aerodynamic design, mechanical limitations, machine life assessment, and physical space limitations both inside the casing of the machine and on the compressor deck when a plant operator is considering new operating conditions for compressors and/or steam turbines. It will help the operator determine whether it is more beneficial to rerate an existing machine, or replace it with a new drop-in machine.
Additionally, the difference in the time it takes to install a rerate and the time it takes to install a new drop-in machine will be evaluated with an eye toward minimizing the duration of a plant turnaround. The role of machine auxiliaries such as oil systems, buffer gas systems, injection systems, and control systems will also be explained.