ELECTRICITY CONSUMPTION IN 1999
Eregli Iron and steel works Inc. (ERDEMIR) is an
integrated steel mill where two blast furnaces are in operation. The function of
the blast furnace in the steel mill is important and vital. Unplanned shutdown
is not permitted. Turbo-blower is the compressor which supplies blast air to
blast furnace. In order to supply blast air without interruption a redundant
blower is needed.
Erdemir has by product gases obtained in the
processes and the excess gases are consumed as fuel in steam generators. After
the cogeneration system is established in Erdemir 100 t/h steam capacity became
as excess. Either this capacity should be used or some by product gases should
With TURBO-GENERATOR/MOTOR-BLOWER PROJECT both
requirement has been satisfied.
A BRIEF DESCRIPTION OF ERDEMIR
The total crude steel production of Turkey
in 1999 is 14,3 million tonnes, ranking as the 17 th. Largest steel producer in
Ereğli Iron and Steel Works Inc. (ERDEMİR)
is the largest steel producer of Turkey and the only integrated steel plant
producing flat steel products. Erdemirs share of the total crude steel
production in Turkey for 1999 was 18 percent.
Erdemir began operation in 1965 and now
has a crude steel capacity of 3 million tons per year. It is located on the
Black Sea coast at the town of Kdz.Ereğli, 270 km away from İstanbul.
Erdemir meets about 40-50 % of domestic
flat steel requirement and exports 20 25 % of its sales, mainly to European
Union, USA and Japan.
The integrated steel plant of Erdemir
occupy a site of 4 square kilometers and include harbour facilities, coal and
iron ore stockyards, coke plant, sinter plant, power house, dam and water
systems. The iron and steel making facilities include two blast furnaces, basic
oxygen furnaces, hot and cold rolling mills.
Erdemirs main strategy is to be a
global company by modernizing the existing facilities with latest technologies
and installing new hi-tech facilities. Erdemir was awarded ISO 9002 quality
systems certificate in 1997. ISO 14 001 environment certificate is under study
and probably will be awarded by the end of this year.
The quality and the price are main factors
in the market. The market itself determines the price. To make a profit the only
parameter which can be controlled is the cost. In flat steel production at ERDEMİR
the cost distribution is,
The only parameter which can be controlled
and reduced is the energy consumption.
In 1982 energy consumption per ton crude
steel was 8220 Mcal.
After the application of many energy
saving projects and modernization, energy consumption per ton crude steel was
5160 Mcal in 1999.
Energy saving percentage is 37 % .
In order to decrease the energy cost the
more by products have to be consumed as fuel in the processes .
In 1997 co-generation, consisting of;
2x38,5 MW Natural Gas Turbo
2x80 t/h Waste Heat Boilers, were taken
into operation .
Steam generators which consume by product
gases had 100 t/h excess capacity because of the waste heat boilers.
ERDEMİR has two Blast Furnaces which
produce 7000 tons/day hot metal.
There are three turbo blowers to supply
blast air to two Blast Furnaces. Two Blowers are in operation in one to one
correspondence and the third one is a stand by as a cold spare . If one of the
operating turbo blowers fails by some reason, the related blast furnace has to
shut down and a certain amount of damage might occur. The cold spare third turbo
blower can be started up nearly in two hours. The hot metal production decrease
and some damage in the Blast Furnace is unavoidable.
In order to prevent such a situation
BLAST FURNACES NEED A STAND -BY MOTOR DRIVEN BLOWER AS A SPARE
THE STUDY FOR;
2- TURBO GENERATOR / MOTOR BLOWER PROJECT
In order to have economical and efficient
operation in industry turbine-generator and turbine-blower are combined together
recently. Instead of having a cold spare blower (blast air copressor) which can
be put into operation in two hours, it is preferred to have a running steam
driven turbo-generator which is capable of driving a blower as soon as it is
needed. This combination is desingned for blast furnace use.
Steam turbine drives the generator to
generate electricity and during the operation it is possible to decrease the
generator load and drive the blower in 90 seconds to give service to the blast
furnace of which turbo-blower has tripped by some reason.
Turbo Generator/ Motor Blower System
As shown Figure 1 consist of;
Steam Turbine (as driver )
Motor-Generator (When steam is available
functions as generator to generate electricity and when steam is not available
functions as Electric Motor to drive the blower)
Voith geared turbo coupling ( Between
Motor/Generator and blower)
Blower (As driven by steam turbine)
MODE 1) STEAM TURBINE GENERATOR OPERATION
(Figure 2) Steam turbine drives only generator for generating electricity (maximum
load 25 MW)
VOITH GEARED TURBO COUPLING UNCOUPLED
MODE 2) STEAM TURBINE GENERATOR BLOWER
OPERATION (Figure 3)
The main purpose of installing this plant is to
provide blast air to BF 1 and BF 2 in case its existing turbo blower fails to
supply blast air due to any reason except planned trip. Normally the plant will
run in MODE 1. During MODE 1 operation if one of the turbo blowers trips, this
machine will automatically engage the Voith geared turbo coupling to drive the
blower and supply air totally in 90 seconds. The plant will supply blast air
with minimum required capacity of related blast furnace.
MODE 3) MOTOR-BLOWER OPERATION
When this plant is stand by (cold spare)
and one of the operating two turbo blowers fails to supply blast air, the motor
will start. When the motor has reached its nominal speed the Voith gear will be
activated and the blower will be coupled. In 90 seconds the blower will provide
blast air to blast furnace.
MODE 4) STEAM
TURBINE BLOWER OPERATION (Figure 5)
Steam turbine drives the generator rotor,
generator rotor only serves as a mechanical clutch and drives the blower through
Voith geared turbo coupling.
All of the operations can be performed
either on automatic or on manual control.
By this project Erdemir will have many
200 million kWh additional electricity
will be generated annually
-The price of purchased electricity is
about 6 cents/kWh
-The cost of generated electricity is
about 4 cents/kWh
(The cost of energy will be less)
All the by product gases will be consumed
in the steam generators. (The cost of energy will be less)
Erdemir will generate 85% of the
Redundancy of the blast air of blast
furnaces will be provided.