AALBORG TABLE OF CONTENTS

INDUSTRIES

Table of contents

Descriptions
MIS SIONTm boiler 1
Boiler mountings 2
Water level control 3
Gauge board 4

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AALBORG MISSION TM OL BOILER SD9214#04.3
IN USTRIES

MISSION TM OL boiler

1 Description
7

The MISSIONTM OL boiler is a vertical two-drum boiler, insulated and pre-

assembled with boiler mountings for easy installation and operation.
The boiler is top-fired and equipped with a steam atomising burner. As the burner,
the local control panel and all relevant boiler mountings are mounted on top of the
boiler, this can easily be operated and monitored from the burner platform. Most of
the cabling for instrumentation and drain are pre-wired before delivery.
The control system supplied with the MISSIONTM OL boiler unit provides fully
automatic operation of the boiler and the steam atomising burner.

1.1 Boiler pressure part

The principal drawing of the MISSION TM OL boiler is shown in Figure 1. The steam
drum is cylindrical with two flat plates of equal thickness. Because of the internal
pressure, the flat plates are mutually connected by vertical solid stays. The steam
drum is furnished with the necessary internal fittings to ensure an even distribution
of the feed water, of the circulation water from the exhaust boiler and to ensure a
sufficient dryness of steam.
The burner cone in the furnace opening are an integrated part and accordingly no
refractory are provided in the top of the furnace room.
Manholes are conveniently placed in both drums and inside the drums enough space
is available for inspection and maintenance.
The water drum is designed similar to the steam drum. The drum size gives optimal
space for the heating coil and easy access for inspection.
As standard the boiler is prepared for tack welding along the foundation of the boiler
shell. Some boilers may, however, be provided with four support feet instead, one as
fixed foot and the others with the possibility of thermal expansion.
Both the furnace and the generating tube bank are located asymmetrically and are
separated by the screen wall. Besides the screen wall the furnace consists of gas
tight polygon shaped membrane watts. The generating tube bank consists of vertical
pin-tubes arranged in a staggered configuration. To avoid any risk of vibration
problems supports are arranged.
The filie gas passes through the deflected tubes at the bottom of the screen wall, up
through the generating tube bank and out through the smoke outlet box.
An effective circulation in the boiler is achieved bye means of down comers.
The bottom tube plate is first covered with coat of insulation refractory and aboye
with castable refractory.
Access to the furnace is possible through the access door at the bottom of the
furnace. Inspection of the generating tubes is also possible through the inspection
door at the bottom of the furnace.
Inspection of the burner flame is possible through the two inspection holes arranged
in two heights on the furnace panel wall.

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AALBORG MISSION TM OL BOILER SD9210#04.3
INDUSTRIES

Principal drawing of MISSIONTM OL boiler

Manhole

1 Burner

Smoke outlet Steam drum

box
E

Inspection hole

Membrane walls
••
Furnace
•
••
Screen
wall
• •
• r
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1^1^1^1^1^^ 0^•:1^1^1^1^1:1^1^1^ 1w • • : • ' • .!.:

Figure 1 miss olb.cdr

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 i
AALBORG BOILER MOUNTINGS SD9220#19.1
INDUSTRIES

oller mountings
:Ioiler
Mountings
The following is a brief description of the most important items of the boiler
mountings. The components mentioned in this section are referring to the general
arrangement drawing of the boiler.
Safety valves
Two safety valves are fitted to the pressure vessel of the boiler. They are installed
for security reasons, and designed to prevent the boiler pressure from rising aboye
the design valve.
The safety valves must be supplied with waste steam pipes and either expansion
devices, or bellows.
Main steam valve
The main steam valve is a shut off/non-return valve. When closed, it isolates the
boiler from the main steam ¡inc. When open, it prevents steam from flowing
backwards finto the boiler.
The main steam fine should be equipped with an expansion joint next or close to the
valve.
By-pass valve
The by-pass valve is a shut off valve. The purpose of the valve is to equalise the
pressure between the boiler and the steam system when the main steam valve is
closed. Please note that the by-pass valve is only supplied for larger boilers,
Feed water valve 1 feed water valve (sdnr)
Two groups of feed water valves are provided in the boiler. Each group comprises a
shut-off valve and a non-return valve.
The shut-off valve in the ordinary group must be open when the boiler is in
operation, or if the boiler is used as a steam drum.
The shut-off valves should be closed when the boiler is not in use.
Water level gauges
Two local water level gauges are connected to the front of the boiler, each gauge
being provided with two shut-off valves and a drain valve.
The shut-off valves, fitted at the top and bottom of the sight glass, have a quick-
closing mechanism to be used in case of broken glass.
The pipes from the drain cocks on the water level gauge must lead to an open drain,
visible for inspection.
Blow-down valve
Two blow-down valves of the ball valve type are mounted at the bottom of the
boiler body.
Air valve
The air/ventilation valve located on top of the boiler is a shut-off valve. It is
normally closed except when the boiler is being filled or completely drained. The

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AALBORG BOILER MOUNTINGS SD9220#19.1
INDUSTRIES

end of the drain pipe from the air valve must be visible in order to determine when
water or steam is coming out.
Scum valve
The scum valve is a combined shut-off/non-return valve. In the event of scum in the
boiler, this scum can be blown off from the water surface by opening this valve.
Valves for WHR inlet and outlet
The boiler is provided with two circulation valves for inlet and outlet connections to
the exhaust gas boiler(s).
The valves should be shut-off valves, and depending on deviations in the system,
these valves can also have a non-return function.
Sample valve
A sample valve is installed enabling connection to a sample cooler for taking test
samples to perform boiler water analyses.
Inspection hole
Two small inspection holes are provided in the furnace wall to enable inspection of
the burner flame. A proportion of the air supply is bled off from the burner fan to
cool the window of the inspection hole, and prevent soot deposits.
Manhole
Two manholes placed at the boiler top and boiler bottom allow inside inspection of
the steam/water drum.
Access doors
Access to the furnace and smoke outlet box are possible through the access doors
placed at the bottom of the furnace and at the smoke outlet box respectively. Both
access doors enable inspection of the generating tube bank.
Drain for furnace
The furnace bottom is provided with a socket for drain of the washing water.

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AALBORG WATER LEVEL CONTROL SD9230#17.0
INDUSTRIES

ater level control

1 Description
The water level control is a modulating system at this type of boiler. The system is
illustrated in Figure 1. The safety device system for too low water level alarm and
burner cut out consists of a level float switch mounted as an extemal unit. For
measuring and control of the water level, the boiler is equipped with a dp water level
transmitter unit, which includes external reference and variable legs, and a dp-
transmitter. The continuous 4-20 mA output signal from the dp-transmitter is
processed in the control system, which provides level warnings/alarms and control
of the regulating feed water valve.

Water level control system

Instrument aír

Regulating feed water valve

,
Feed water
valves ,

,,
Reference ieg
,
,

Variable Ieg ,
Boiler T ,

Valve Control
manifold system
(panel) ,
dp-transmitter ,
,

Feed water pumps

r-i r-^ r1

Figure 1 dp_1_mod.cdr

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AALBORG GAUGE BOARD SD9240#10.0
INDUSTRIES

Gauge board

11 Description
The function of the gauge board is to control the burner and to give warning and
alarm for low and high steam pressure.
• A pressure gauge is fitted for analogous reading of the actual steam pressure in
the boiler. The pressure gauge is located on the local control panel.
• A pressure switch "high steam pressure" gives alarm and cut-off the burner
when the steam pressure rises aboye the pre-adjusted set point. Furthermore, the
pressure switch locks the burner in stop mode. Operation of the burner is only
possible when the steam pressure falls below the differential set point of the
pressure switch and the alarm is reset.
• A pressure transmitter connected directly on the boiler converts the actual steam
pressure of the boiler finto corresponding electric signals. The signals are used to
give warnings for low/high steam pressure and alarm/burner cut-off for high
steam pressure. Furthermore, the signals are used to control start/stop and
modulation set point of the burner.

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