Blade Failures on an Axial Compressor by Unexpected Gas Compositions

Abstract

A fifteen stage axial compressor including a bleed extraction was subject to a major overhaul after nearly 20 years of trouble free operation. Shortly after recommissioning and resumption of the production the compressor faced three major failures within two weeks. A root cause failure analysis was conducted and revealed that the process plant start-up procedures caused gas compositions which deviated strongly from the design conditions. The valve designs as well as the available control parameters were not able to protect the compressor from off-design operating conditions. For future compressor failure prevention, the process start-up procedures were adapted and the existing control parameters/logic was upgraded. The new control logic reacts to the transient process behaviours during start-up by continuous harmonization of the safety valves.