Measure Implemented
 |
Repair of compressed air leakages |
|
Rolling Mill 2 Reheating Furnace (RF)-furnace door
a d j u s t m e n t |
|
Replacement of old piston type air compressors with
new screw type air compressors |
|
Installation of Variable Speed Drives (VSD) |
|
Power factor improvement |
|
Timer Control for Air conditioning and lighting –
Production and Main offices |
Benefit
|
Total annual energy savings of 6581 GJ/yr . |
|
Total annual cost savings of RM 322,000 /an., and |
|
Annual CO2 reduction – approximately 1256 tonnes/an.
|
|
Simple payback period of 1.5 years |
Summary
In November, 2001 the MIEEIP team carried out an energy
audit exercise at Malayawata Steel Berhad . The objective of
the audit was to identify energy savings, energy cost savings
and reduction of C02 emission opportunities. During the
audit the MIEEIP team together with factory personnel
identified several no-cost, low-cost and high-cost energy
saving measures.
Recognising the cost-effectiveness of the audit
recommendations, the company has invested more than RM
400,000 for the implementation of some of the measures,
and has recorded:
Energy savings of 6581 GJ/yr,
Energy cost savings of RM 322,000 /yr., and
C02 reduction of 1256 tonnes/yr.
In addition to the measures proposed by the MIEEIP team the
Company has identified other measures on its own, and
successfully implemented them.
Company and Plant Overview
Malayawata Steel Berhad was incorporated in June 1961. It
has been listed on the Main Board of the Bursa Saham Kual a
Lumpur since 1967. Malayawata is a pioneer in the
Malaysian steel industry and was the first integrated steel mill
in South East Asia .
The factory’s core output is the production of steel bars and
wire rods, where close to a million tonnes of steel bars and
wire rods were produced for the year 2004.
In its early days, Malayawata an integrated steel producer,
started with one ch a rcoal based Blast Furnace, one 15 tonnes
Basic Oxygen Furnace and one Rolling Mill producing some
40,000 to 50,000 tonnes of steel bars for reinforced concrete.
The company has expanded over the years, taking advantage
of new and more efficient developments in steel making
technology.
Presently, Malayawata has a new electric arc
furnace replacing the old blast furnace. They also have
expanded their production with a second rolling mill plant.
At Malayawata, the iron and steel making processes are
d ivided into two distinct parts namely Steel making and
Rolling mill. The Steel making plant (SM2) converts steel
scrap into billets. The steel making process starts with the
transport of scrap using cranes and buckets from a huge scr p
yard to the plant, where it is discharged into the DC Electric
Arc Furnace (EAF).
The EAF operates in a batch melting mode producing batches
of molten steel of approximately 80 tonnes of molten steel
e a ch. Upon achieving the desired steel composition and
temperature (approximately 1600°C) in the EAF, a tap-hole is
opened and the steel is poured into a pre-heated ladle,
which
will then be transported using a ladle car to the AC ladle
furnace (LF) station. At the LF heat energy is supplied via
three AC electrodes to control steel temperature. During the
process, alloys such as SiMn, Lime, Coke, FeSi, FeMn etc. are
added into the LF in order to control the steel chemical composition based on analysis and the steel grade to be
produced (customer specification).The ladle containing refined
molten steel is then transported by over-head cranes to the
casting plant.
The casting plant operates as a continuous casting process,
converting molten steel to billets. Here, the billets are cooled
in the storage area before being transported to the rolling mills.
Billets need to be heated from atmospheric temperature to
about 1300°C before being rolled in the mill.
The reheating process is divided into two or three zones
namely the heating zones and soaking zone. Heat is
provided for each zone by a series of fuel oil burners (diesel
oil, supported by atomizing medium) located across the
furnace. The flue gas produced from the combustion exits the
furnace at about 600°C.
At the Rolling mill the billets are converted into finished
products such as deformed bars and wire rods.
Simplified Process Flow Diagram of the steel making and Rolling Mill process |
Project Overview
During the energy audit exercise numerous potential no-cost,
low-cost and high-cost measures were identified. In addition
to these measures the company has also identified and
implemented other energy saving measures. The following
measures have been implemented during the years 2003-
2004 .
1. Rolling Mill 1 (RM1) -Repair of compressed air leakages
The audit team carried out an air leakage test at RM1
compressed air system using the opportunity of RM1 roller
size change, and found that substantial leaks exist in the
compressed air system. The team recommended that the air
leakages are identified and repaired.
Measures Implemented |
Investment
(RM) |
Total Annual
(RM) Cost Saving |
| Rolling Mill 1 - Repair of compress air leakeges |
NIL |
322,000 |
| Rolling Mill 1 - Replacement of old piston type air compressors |
RM 80,000 |
| Rolling Mill 2 - Replacement of old piston type air compressors |
RM 300,000 |
| Rolling Mill 2RF - Furnace door adjustment |
RM 8,000 |
| Rolling Mill 2 Steel quenching pumps, installation of VSD |
RM 54,000 |
| Rolling Mill 2 colling blower fan for mill drive installation of VSD |
RM 54,000 |
| Power factor improvement |
NIL |
| Timer control for air conditioner and lighting (load management) |
100 |
Measure Implemented
Malayawata undertook an exercise to identify and reduce
leakages in the compressed air system of RM1, this measure
is a no-cost measure (needing no capital investment from the
company).
It is not possible to eliminate all leakages in a compressed air
system. For a medium size network a 5-7% leakage is
acceptable. Common locations of compressed air leakage
are :
Air using equipment left connected when not required,
Leaking pipes and joints,
Leaking hoses and couplings,
Leaking pressure regulators,
Shut off va l ves left open, and
Mistreatment of air guns.
It is important to note that compressed air is an expensive
s o u rce of energy and leakages in a compressed air system
can lead to significant energy losses and energy cost
escalation .
2. Rolling Mill 1- replacement of 2 old piston type air
compressors with 1 new screw type air compressor
During the MIEEIP energy audit the team noted that the
compressor station supplying the rolling mill with
compressed air consists of 3 compressors. Demand for
compressed air in the rolling mill line is met by running only
one compressor. The main consumer of this station is the
rolling mill line especially the hydraulic actuators at the
packing area. As, the operating pressure of this air system is
similar to RM1 Reheating Furnace (RF) compressed air
system, the possibility of integrating these two systems
together was investigated. Leakage test and load test was
conducted at this site.
Malayawata conducted a study on the workings of the
compressors and found that maintaining three air compressor
units was energy inefficient and also costly.
Measure Implemented
The company replaced the old piston type air compressors
with one new screw type compressor; and this enabled the
company to run plant operations with just one 75kW
compressor instead of two 75kW compressors as previously
done.
3. Rolling Mill 2RF furnace door adjustment
During the audit it was noted that under-pressure is
maintained in the RF, while the front part of the furnace is
slightly over pressurized to ensure that the temperature of
billets is maintained when they are discharged onto the
rolling mill train. The audit team found that both the
discharging door and the manipulation door of the RF
showed signs of leakage.
The team proposed that the following changes are made:
Setting the overpressure to a minimum
Adjusting the outlet door downer position 200 mm
lower
Repairing the support of the manipulation door so that
the inclination of the door is avoided
Due to the high temperature of the leaking flue gases and
relat ively high speed of the leak caused by low flue gas
density at that temperature, the savings from this measure are
expected to be high.
Measure Implemented
The energy management team at Malayawata implemented
two out of the three above mentioned recommended
measures. As per the MIEEIP audit recommendations the
team adjusted the outlet door downer position to 200 mm lower and they also repaired the support of the manipulation
door so that the inclination of the door was rectified.
4. Rolling Mill 2 (RM2) replacement of 3 old piston type air
compressors with 1 new screw type air compressor
RM2 consisted of three piston type air compressor units;
however, compressed air was supplied by only one out of the
3 compressors. The working compressor was operating at its
full capacity, while the second compressor was idling
continuously and was kept in operation for safety reasons. The third compressor was kept in stand-by mode.
Malayawata conducted a study on the workings of the
compressors and found that maintaining three air
compressor units was energy inefficient and also costly
Measure Implemented
In June 2004, the company replaced all 3 old piston type
air compressors with one new screw type compressor at a
cost of RM 300,000/- ; this exercise enabled the company to
run plant operations with just one compressor instead of two
previously. The change resulted in a 28% reduction in
p ower consumption from 380 kW to 275 kW.
5. Rolling Mill 2 steel quenching pumps Variable Speed Drive (VSD)
The system is designed to use throttle valves to reduce the
high pressure of quenching water to the required pressure.
The actual efficiency of the quenching pumps is low due to
wear and tear from the high number of operating hours and
infrequent overhauling. As VSDs can give considerable
savings, the audit team recommended for the company to
conduct a more detailed energy audit in which the
characteristics of the quenching pumps and the piping are
measured so that exact figures may be used in the
calculation to evaluate the cost-effectiveness of installing
VSDs. The team proposed to equip one 200 t/hr and another
400 t/hr quenching pump with frequency inverters.
Measure Implemented
For the period between November, 2003 and January, 2004,
the energy management team at Malayawata installed three
variable speed drives at the water plant pumps. Two units of
160 kW VSDs and one unit of 225 kW VSD were installed.
The team found that the ave rage power consumed by each
unit was 120 kW as against 160 kW previously consumed,
thus giving a saving of 25%.
6. Rolling Mill 2 cooling blower fan for mill drive motor
The cooling process takes place after the rolling process.
The finished sections are sheared and delivered onto the
cooling bed. Here the bars/rods are cooled through a bed
by blower fans that blows air from the bottom. RM2 is
equipped with 3 units of cooling blower fans in order to
control the cooling temperature profile of the bars/rods. All
these fans were driven by a motor at a constant speed.
Measure Implemented
After looking at the advantage of variable speed drives at the
quenching system, the energy management team decided
to install variable speed drives at each unit of the cooling
blower fans so that the speed of the motors can be
controlled at an optimum setting without any interruption to
the production. The motor speed for 2 units of 37 kW motor
is reduced from 975 rpm to 800 rpm resulting in a reduction
of power consumption from 30 kW to 24 kW and for motor
speed of 75 kW motor is reduced from 785 rpm to 700 rpm
resulting in a reduction of power consumption from 45 kW
to 39 kW.
7. Power Factor Improvement
Industrial power users have to pay a low power factor (pf)
penalty if the pf of their installation is lower than 0.85.
Rectifying the pf to a value higher than 0.85 eliminates the
pf penalty. Such initiatives are cost-effective and have a very
short pay back period
Measure Implemented
Between December, 2003 and May, 2004 the company
improved its power factor from 0.7 to 0.9. This was
a chieved by adding 1 MVAR capacitor bank at the Steel
Making Plant (SMP) 11kV and SMP Water Plant. This
resulted in a 22% reduction of the apparent power drawn
from the power system.
8. Timer Control for Air conditioner and lighting
In early 2003 the company carried out renovation works to
the main office and production office. To maintain good
house-keeping the company decided to include the
installation of a timer control for the air conditioning and
lighting system for both the main office and production
office areas. The energy management team found that with
the installation of the timer control system human errors can
be prevented, as the air conditioner and lights will
automatically shut off at the programmed time.
Conversion from the use of diesel to natural gas
The company is currently making final arrangements to
sw i t ch from the use of diesel and light fuel oil to natural gas
due to the competitive gas price. Another motivating factor
for the sw i t ch is the fact that natural gas is the cleanest of all
the fossil fuels. The combustion of natural gas releases very
small amounts of sulphur dioxide and nitrogen oxides,
virtually no ash or particulate matter, and lower levels of
carbon dioxide, carbon monoxide, and other reactive
hydrocarbon s .
Management - driven commitment towards EE
The success of EE activities in any factory relies heavily on
the attitude and far sightedness of the top management in
realizing the benefits of EE. At a recent interview,
Malayawata Division Head Mr Ye ow Kheng Kooi and
Section Manager En Wan Ali Wan Ismail explained that the
company is now able to implement EE measures in the
factory due to the setting up of an energy management
team, this team was instrumental in analyzing and
implementing the measures proposed by the MIEEIP audit
team. The energy management team is also actively seeking
for ways to further improve the ove rall energy performance
of the factory
They also explained that though the company realised the
potential benefits of EE , aspects such as availability of
budget , the efficiency of old machines, interruption to
op e rating processes and factory personnel getting used to
new machines and systems will need to be looked into.
Malayawata understands that by implementing EE measures
a company can increase its competitiveness through
operating cost reduction and improvement in machine
performance. Demonstrating the qualities of a good
corporate citizen the company also considers the social and
environmental benefits when implementing EE measures.
