Fig. 20: Load/Time Chart; Table 18: Operating Point For Turbine Cleaning - ABB PT004165 Operation Manual

Operation Manual / Power2 850-M / High-pressure stage
7 Periodic maintenance / 7.3 Cleaning turbine and nozzle ring during
operation
7.3.3 Wet cleaning of turbine blades and nozzle ring
Cleaning procedure
The individual phases of the turbine cleaning procedure are shown in the following illustra-
tion.
Fig. 20: Load/time chart
1. Cool down phase
Reduction of the engine load to the operating point for turbine cleaning and subsequent
u
maintenance of the holding time according to the specifications in the following table.
Power2 Gas pulse at
the inlet in the
HP stage
[N/m
850 9500 ±2500
Table 18: Operating point for turbine cleaning
Algorithm for the gas pulse
For an optimum cleaning result, the gas pulse adopted when designing the cleaning process
should be set via the control system on the engine side. The algorithm for the gas pulse is
specified in the section
cified engine load point is to be set as an approximation.
Thermomechanical stress
Due to the thermomechanical stress of the turbine casing, the gas inlet temperature should
not exceed the specified maximum temperature before starting cleaning. If this is the case,
the engine load is to be lowered until the permissible temperature is reached.
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Gas pulse at
the inlet in the
LP stage
2 2
] [N/m ]
3200 ±800
Calculation of the gas pulse
HZTL4063_EN
Engine load Max. gas inlet
temperature
[%]
when starting
cleaning
[°C]
25 430
→58. If this is not possible, the spe-
Holding time
at reduced
load
[min]
≥10
Rev.F March 2022