HDK-201004-v001 Case Story Plzen.indd - Howden

CASE:
NEW BOILER AND FGD PROCESSES
CALLED FOR A TOTAL CHANGE OF THE
ID/BOOSTER FAN.
HOWDEN’ S SOLUTION WAS TO
INSTALL A COMPLETE NEW FAN ON
THE EXISTING FAN FOUNDATION
REDUCING BOTH COSTS AND DURA-
TION OF THE PROJECT.
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INSTALLING A BRAND NEW FAN
ON AN EXISTING FOUNDATION
THE CHALLENGE
In 2008 the power plant of Plzen, Czech
Republic, owned by Plzenska energetika
a.s., planned to do a boiler refurbishment.
At the same time the FGD from the midnineties
had to be upgraded in order to
comply with today’s demands for bringing
down emissions.
The changes in the power plant processes
caused a demand for a total change of the
performance of the ID/Booster fan.
HISTORY
The original ID/Booster fan which alone
served all three boilers of the 346 MW
power plant was delivered by Howden in
1995. It was a single stage fan type ANN-
2500/1250N, speed of 990 rpm, and with
medium pressure blade profiles of aluminium
with wear noses and a cast hub.
The maximum operating temperature was
75°C, the Test Block volume = 198 m 3 /sec
and Test Block pressure = 2469 Pa. The
motor size was 750 kW.
OUR SOLUTION
First of all Howden provided a brand new
fan solution to meet the performance
demands.
It was a considerable bigger fan of the type
ANN 3200/1600B, speed of 740 rpm. The
new and strong fabricated hub was provided
with high pressure profiles of nodular
cast iron. The maximum flue gas temperature
had to be 160°C, the Test Block volume
= 360m 3 /sec and Test Block pressure = 2275
Pa. The new motor size was 1050 kW.
Total Fan Pressure (Pa)
x 1000
3.0
2.0
1.0
0.0
0.0 100 200 300 400 500 600 700
Volume Flow Rate [m 3 /s]
Black curve = Performance of the original fan
Red curve = Possibilities of the new fan

Suction box and diffusor of the new fan placed on the foundation
During the planning phase Howden presented
three alternatives concerning the fan
foundation:
•
•
•
The first option was to place the new
fan directly on a new standard foundation.
The second option was to establish a
support of springs between the new
fan and a new foundation.
The third option was to reuse the old
foundation from 1995 and modify it to
fit the new fan.
For further information on Fan Retrofi t and
Enhancement please visit www.howden.com
or contact your local Howden company
The plant had a very tight time schedule for
the upgrade process. In order to meet that
it was chosen to keep the existing foundation
of the original fan from 1995, modifying
it slightly with steel supports in each end
– one for the new motor and another for the
transport skates for the diffuser.
To secure that the foundation met all the
requirements of stiffness and frequency,
Howden also provided a thorough Foundation
Test consisting of a Fan Survey, Balance
Tests and Bump Tests.
www.howden.com
Keeping the existing foundation ensured
Plzenska energetika a.s that the erection
time and costs were reduced to an absolute
minimum.
THE RESULT
The power plant of Plzen obtained all the
advantages of a brand new fan:
•
•
•
•
Optimum efficiency
Improved operational reliability
Performance suited for the actual
operation values
The latest developed fan technology
And Plzen experienced savings by using the
existing foundation:
• No demand for establishing a brand
new foundation
• Minimum adjustment of existing foundation
and ductwork
• Cut down on total erection time – minimum
downtime
• Huge price savings for the total project
CONTACT HOWDEN
For more information on performance
upgrades, extension of fan lifetime/maintenance
intervals, and new features please
contact Howden for further advice and
information.
Howden Denmark A/S. All rights reserved. 2009
HDK-201004-v001/Case Study Plzen