Functions Cleaning fluid sprayed into the compressor during the cleaning operation collects at several locations in the gas turbine.. Configuration Cleaning fluid is drained off at the
Trang 1DRAWING/DOCUMENT STATUS FOR REFERENCE
PROJECT :
CAMAU 1 750MW COMBINED CYCLE POWER PLANT
PETRO VIETNAM CPMB
s
DRAWING TITLE :
System Description Drainage System
Ursprung/Original Ursprung-Nr./Original-No Urspr.-PKZ-Nr Orig.-PC
Datum
Date
Name Maßstab
Scale N/A A4 UA/DCC Type XS00
gezeich
Drawn 06-04-10 STEENM Benennung/Title
Inhaltskennzeichen Contents Code bearb
Coord 06-04-10 LIEDTKE
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Refer also to:
List of Control Settings (SREL) 3.1-0210
List of Electrical Loads 3.1-0230
Equipment List 3.1-0240
P+I Diagram, Drainage System 3.1-1210
P+I Diagram, Blowoff System 3.1-1410
P+I Diagram, Turbine Cooling 3.1-2010
Settings, limits and measuring ranges of the devices
listed here are given in the List of Measuring Instruments,
Equipment List and List of Control Settings (SREL) This
description only gives guideline values
Functions
Cleaning fluid sprayed into the compressor during the
cleaning operation collects at several locations in the gas
turbine This fluid is removed via the drainage system
before the gas turbine is restarted
Danger!
Risk of scalding! The compressor cleaning operation and also the subsequent draining operation are performed manually I.e the switches and valves must be operated by hand It is absolutely imperative that all the valves opened during the draining operation
be closed once draining has been completed If they are not closed, hot gases will escape from the drainage piping and equipment may be damaged or persons injured In addition, crosscurrent flow may occur between the individual gas turbine drain connections
Configuration
Cleaning fluid is drained off at the following gas turbine locations:
1 Compressor stage 0
2 Compressor stage 9
3 Compressor stage 13
4 Compressor outlet
5 Turbine stage 2
6 Turbine stage 3
7 Turbine stage 4
8 Extraction ring E1/A1 stage 5
21 Compressor stage 5 blowoff line
22 Compressor stage 9 blowoff line
23 Compressor stage 5 cooling air line
24 Compressor stage 9 cooling air line
25 Compressor stage 13 cooling air line
26 Compressor stage 13 cooling air line
Pipes connect these locations to header MBA25BB001
The shutoff valves in these lines must be opened manually
to drain cleaning fluid and then closed after completion of draining Cleaning fluid must be routed from header MBA25BB001 via connection 30A and a hose line to a disposal tank, the latter of which must be supplied locally
The header only has a small volume and therefore cannot function as a collecting vessel For this reason it must be ensured that the cleaning fluid can freely flow from the header into a disposal tank at all times A venting nozzle prevents the buildup of pressure in the collecting tank
When cleaning the compressor, some of the cleaning fluid flows to the lowest point of the compressor intake structure which is not depicted in the P+ID This lowest point is connected to the disposal tank via a duct which has
no shutoff valve Instead the duct contains a hydraulic seal which must be filled with water before the gas turbine is started up During operation of the gas turbine this hydraulic seal prevents the subatmospheric pressure that prevails upstream of the compressor from drawing air in the disposal tank into the compressor
The shutoff valves of the blowoff system drains and also those of the turbine cooling system drains are depicted in the drainage system P+ID
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Fuel Oil Drainage System
When the gas turbine is started on liquid fuel (fuel oil),
the latter is injected into the combustion chamber during
the ignition phase In the event that the flames do not ignite
immediately on startup with fuel oil⎯or if they initially light
and then extinguish⎯fuel oil may precipitate on the
combustion chamber walls This uncombusted fuel oil must
be drained off before the gas turbine is restarted Draining
is achieved via the same pipe connection at the
compressor outlet that is used to drain the spent cleaning
fluid after cleaning the turbine or compressor
Three-way solenoid valve MBA22AA001 is used to
route fluid from this drain, either to shutoff valve
MBA22AA251 or to a drain pipe equipped with solenoid
valve MBA22AA002 The fuel oil must be fed from
connection 111A into a disposal tank for used oil (supplied
locally) This tank must have provision for continuous
venting since air can also escape at connection 111A
These solenoid valves remain in their drainage settings
during standstills or turning gear operation to allow any
uncombusted oil that collects to drain off For this purpose,
these two solenoid valves are always actuated to their oil
drainage setting at speeds below S.TURB.05 (for example
5% rated speed) 3-way valve MBA22AA001 then has the
setting “A-C open; B closed” and solenoid valve
MBA22AA002 is open
Solenoid valve MBA22AA002 is closed in one of the
first steps of the fuel-independent startup program During
a start with fuel oil, the 3-way valve is actuated such that
the fuel oil drain is open (A-C open; B closed) as it cannot
be ascertained in advance whether the start will be
successful or aborted These solenoid valve settings
ensure that any fuel oil which may collect does not enter
the water drainage system and no hot air can escape from
the fuel oil drainage system In the case of a fault-free start,
the 3-way valve is actuated to its drain setting “A-B open; C
closed” when flames are detected in the combustion
chamber A distinction is made between two types of failed start:
Fuel oil is injected without formation of flames If this type of failed start occurs, the absence of a signal from the flame monitor keeps the 3-way valve in its fuel oil drainage setting
Fuel oil is injected, flames initially form, however they subsequently extinguish This type of failed start is always followed by GT trip When flames extinguish, the 3-way valve receives the signal “Flame out” from the flame monitor and is returned to the fuel oil drainage setting
Each time the gas turbine is shut down, including after failed starts, both solenoid valves are energized, i.e
actuated to their oil drainage settings, when speed drops below S.TURB.21 (for example 25% rated speed) After a failed start, oil flows via connection 111A into the used oil disposal tank At speeds below S.TURB.21 it is ensured that pressure does not become excessive when draining oil from the combustion chamber and thus that oil and air cannot flow into the leakage oil tank at an impermissibly high velocity To ensure that all uncombusted oil collecting after a failed start has sufficient time to drain out of the combustion chamber, it is not possible to restart the gas turbine until monitoring period K.ENTOEL.01 (for example
5 minutes) has elapsed
Wastewater that accumulates during compressor cleaning must be drained off To do this, solenoid valves MBA22AA001 and MBA22AA002 must be manually actuated to their drain settings At speeds below S.TURB.05 (for example 5% rated speed) these solenoid valves can be actuated manually
These solenoid valves are equipped with limit switches
If none of the solenoid valves are in the drain setting during operation at high speed (>S.TURB.21) the protection system alarm “Fuel oil drainage valve not closed” is issued and overall trip is triggered