31 9800 9073 e 2005 03

DRAWING/DOCUMENT STATUS

A

FOR REFERENCE

2006-04-10

First issue

Steenmeyer

DATE

DESCRIPTION

Bearb.
Coord.

Rev.

Liedtke

Sudhoff

Geprüft
Checked

APPD.

PROJECT :

CAMAU 1 750MW COMBINED CYCLE POWER PLANT
OWNER :

OWNER’S ENGINEER :

PETRO VIETNAM
CPMB
CONTRACTOR :

CONTRACTOR’S ENGINEER :

LILAMA CORPORATION

FICHTNER

SUBCONTRACTOR’S NAME :

SUBCONTRACTOR’S SUPPLIER :

s

BOGE

POWER GENERATION
DRAWING TITLE :

System Description Pneumatic System
PKZ

UAS

Contents Code

Ursprung/Original

Reg. No.

UNID

Urspr.-PKZ-Nr.
Orig.-PC

Ursprung-Nr./Original-No.

Projekt/Project

gezeich.
Drawn
bearb.
Coord.
geprüft
Checked

Abtlg.
Dept.

PKZ/PC

Datum

Date

Name

06-04-10

STEENM

06-04-10

LIEDTKE

06-04-10

SUDHOFF

P415

sgd.

s AG
POWER GENERATION

CA MAU 1 CCPP

VIT154

Maßstab
Scale

UA/DCC
Type
Inhaltskennzeichen
Contents Code

N/A

A4

Benennung/Title

System Description Pneumatic
System
Dienstst./Dept.

P415

UNID

423217085

XS00

MBX98
Zähl.-Nr.
Reg.-No.
Index/Rev.

355025
Version

A
Blatt-Nr./Page-No.

CM1-L1-M-MBX98.08-355025
Erstellt mit/designed with

Ersatz für
Supersedes

0 of 2


Gas Turbine
Description of Auxiliary Systems

Pneumatic Control Equipment
Pneumatic System

Refer also to:
List of Control Settings (SREL)
List of Measuring Instruments
List of Electrical Loads
Equipment List
P+I Diagram, Pneumatic Valves and Piping

3.1-0210
3.1-0220
3.1-0230
3.1-0240

3.1-9810

Settings, limits, and measuring ranges of the devices
referred to here are given in the List of Measuring
Instruments, Equipment List, and List of Control Settings
(SREL). The values stated in this description are only given
as examples.

The reproduction, transmission or use of this document or its
content is not permitted without express written authority.
Offenders will be liable for damages. All rights, including
rights created by patent grant or registration of a utility model
or design, are reserved.

Description
Compressed air is the working medium used by the
pneumatic actuators of various components in the gas
turbine auxiliary systems. As a rule, these pneumaticallyactuated valves are relevant to safety. For safety reasons,
the supply of compressed air to the gas turbine is therefore
independent of the power plant compressed air network
and is generated by a pneumatic station. Optionally, valves
in other systems can be supplied in addition to the blowoff
valves. In such cases, this information is depicted in the
corresponding P+I diagrams.

Configuration and Function of
Compressor Train
The compressed air station is equipped with two
redundant trains. Each train essentially comprises a
compressor, a cooler, and a filter. The system has full

redundancy, i.e., the capacity of each compressor train is
sufficient to ensure a reliable supply of control air to the
auxiliary systems (2x100%).
The two trains have an identical configuration, for this
reason only one train is described in the following.
Electrically-driven
compressor
MBX21AN001
compresses air. Filter MBX21AT001 prefilters the air as it
is drawn into the system.
Relief valve MBX21AA191 protects the compressor
against excessive pressure.

Class: RESTRICTED

Solenoid-type pressure relief valve MBX21AA501 is
installed downstream of the compressors to prevent the
reciprocating compressors from having to start up against
pressure (startup assistance). This solenoid valve is open
when the associated compressor is at standstill and is
closed after the compressor is switched on.
The escaping compressed air and any condensation
that forms are fed into condensation collecting tank
MBX23BB001. The condensation collecting tank is
equipped with silencer MBX23BS001 to reduce noise when
discharging compressed air to the atmosphere.

Siemens AG
Power Generation

Condensation that accumulates in the condensation
collecting tank is then fed to disposal tank MBX23BB002
that is at atmospheric pressure. Because the condensation
may contain oil, its disposal must comply with requirements
that apply to used oil.
Swing check valve MBX21AA201 prevents venting of
the train when the compressor is shut down.
Compressed air is dried in the next step. Compressed
air is cooled in chiller-type compressed air drier
MBX22AT001. Moisture condenses, thereby bringing the
air to the prescribed dew point pressure. The separator
system in the cooler separates water and oil from the
stream of compressed air. Condensation is removed via
drain MBX22AT011.
Any dirt particles or oil droplets still present in the
compressed air are removed by filter MBX22AT003. An
optical differential pressure indicator equipped with
differential pressure switch MBX22CP001 is provided at
the filter. A group fault alarm is annunciated if the
differential pressure setting of this switch is violated (cf.
subsection “Monitoring”). Then the filter element must be
replaced.
Condensation
is
removed
via
drain
MBX22AT013.
Shutoff valve MBX22AA251 can be used to isolate the
train for maintenance purposes, even during plant

operation.
The two trains merge downstream of the shutoff valve.
Swing check valve MBX23AA201 prevents the escape of
large volumes of air from the tank if there is a leak in one of
the trains.
Compressed air tank MBX24BB001 is used to store the
compressed air after it has been dried and cleaned.
Pressure control valve MBX24AA151 maintains system
pressure even during extended outages and in the case of
minor leaks. It only opens if pressure in the tank exceeds
the startup pressure of the compressors. Orifice
MBX24BP001 ensures that only a very small flow or air can
be returned even in the event the pressure control valve
malfunctions.
Tank pressure can be read off gauge MBX24CP501.
System pressure is limited by safety valve MBX24AA191.
Shutoff valve MBX24AA401 can be used as necessary
to check whether condensation has formed in the tank.

Open-loop Control
The open-loop control system for the pneumatic station
constitutes a black box for the gas turbine I&C system.
Once the pneumatic station has been started up by
manually actuating the main power switch, no further

3.1-9800-9073/1
0305E-X


Gas Turbine

Description of Auxiliary Systems

switching actions on the part of the gas turbine I&C system
are required for control of the pneumatic station.
The open-loop control equipment and power supply for
the electrical components are located in a separate
junction box for each compressor train (MBY40GH001 and
MBY40GH002 not shown).
Each of the compressors is provided with a dedicated
pressure switch (MBX24CP003 and MBX24CP004,
respectively) for startup and shutdown. These two switches
have the same pressure setting.

The tank pressure is monitored by pressure switches
MBX24CP001, MBX24CP002, and MBX24CP008. If tank
pressure drops below the setting of pressure switch
MBX24CP001, the pretrip alarm "PRESSURE LOW" is
annunciated. If pressure in the tank continues to decline,
pressure switches MBX24CP002 and MBX24CP008

operate, gas turbine trip is triggered (2-of-3 logic gating),
and the alarm message “Pressure TOO LOW” is
annunciated.
The messages “Compressor 1 ON” and “Compressor 2
ON” are displayed on the operation and monitoring system.
If the compressors are in operation for extended periods, it
can be assumed that the system is no longer leak-tight.
The pneumatic system, including all piping, must then be
checked for leaks.
The alarms “Fault in train 1” and “Fault in train 2” are

group fault alarms and are displayed on the operation and
monitoring system. If one of these alarms is annunciated,
the affected compressor train must be shut down and
serviced. Potential causes include, for example: response
of compressor circuit breaker, drier malfunction,
condensation separator malfunction, startup assistance
solenoid valve NOT CLOSED, response of filter differential
pressure switch, loss of power supply.

Class: RESTRICTED

The reproduction, transmission or use of this document or its
content is not permitted without express written authority.
Offenders will be liable for damages. All rights, including
rights created by patent grant or registration of a utility model
or design, are reserved.

Monitoring

Pneumatic Control Equipment
Pneumatic System

Siemens AG
Power Generation

3.1-9800-9073/2
0305E-X