ABB Power2 550-M44 Operation Manual page 67

Operation Manual / Power2 550-M / High-pressure stage
7 Periodic maintenance / 7.4 Cleaning turbines and nozzle rings during
operation
Repetitions of wet cleaning
The repetition of cleaning cycles one immediately after the other must be avoided as this
can lead to excessive mechanical stress and thus to a reduction in the operating life of the
components.
If the cleaning process is ineffective, the duration can be extended. If the injection time is ex-
tended, it is important to ensure that no impermissible volume of water collects in the gas
outlet casing. A drainage system should be installed for the gas outlet casing and opened
during cleaning. If there is no drainage system, the amount of water injected can be mon-
itored with a flowmeter in the water supply. The permitted amount of water must be de-
termined together with a Turbo Systems service station.
The action of the cleaning water on the peripheral units (such as boiler) must be clarified by
the operator.
Draining the gas outlet casing of the low-pressure stage
The following points must be observed with regard to draining the gas outlet casing:
¡
The exhaust gas temperature downstream of the low-pressure stage drops drastically
during cleaning (typical gas outlet temperatures during cleaning: 60...180 °C)
¡
Depending on the engine load, the drainage can take place through the drain pipe. This
drainage may occur after 2 ... 3 minutes or not at all.
¡
If the drainage of the gas outlet casing is omitted, the low-pressure stage speed and/or
the gas inlet temperature must be monitored during the cleaning process. If the load is
too low, water can collect in the gas outlet casing. Indications for this are a sudden
severe drop in the low-pressure stage speed or a very large increase in the gas inlet tem-
perature. In such cases, the cleaning operations must be stopped and the cleaning cycle
restarted with reduced water pressure or higher engine load.
© Copyright 2022 ABB. All rights reserved. HZTL4058_EN Rev.F March 2022