ENERGY AUDIT
PROJECT AT PATWARI
STEELS P LTD
BY
LEAD CONSULTANT:
PHILIP G ITTYERAH
1
EE Report for Patwari Steels P ltd
FOREWORD
This study has been undertaken by State Bank of India under its Project
Uptech, in its endeavors for the up-gradation of technology in the SME
Sector Industries in the States of Jharkhand & Bihar. In a rapidly changing
industrial environment there is a clear need for every entrepreneur to
respond quickly to the atmospheric stimuli and to build upon its internal
capabilities to become a world class competitor. SBI would like the
entrepreneur to think globally, if he has not already initiated this thought.
In this, continuous technological Upgradation is a vital challenge to be
met.
State Bank’s Project Uptech is meant to support the endeavors of the
entrepreneur in this direction. Successful technological development
requires the commitment of the management and hard, systematic long
term efforts stemming, basically, from the entrepreneurs convictions. At
the
same
time,
State
Bank’s
Project
Uptech
also
addresses
the
environmental concerns as expressed by the Kyoto Protocol and has been
formulated on the lines of the concept on Energy Efficiency developed by
World Bank & UNF_UNEP (United Nations Foundation, United Nations
Environment Programme). It was desired by the international agencies
that Commercial Banks should promote and finance Energy Efficiency
projects
This study is only a beginning. Right now it may not find solutions to all
requirements nor present radical changes. This cannot be, because, in any
case, technological evolution is a long term process. State Bank of India is
confident that this will however, grow into a continuous process of
constructive co-operation between the Bank and the Industry to reach the
common
objective
of
attaining
national
importance
and
global
competitiveness
2
EE Report for Patwari Steels P ltd
CONTENTS
Sl No
Description
Pages
1.
Foreword
2
2.
Introduction
4
3.
Facilities – Scenario before and
after Project
6-16
4.
Study details – Methodology and
recommendations
17 - 20
5.
Line drawings
21
6.
Baseline – Project – Bench mark
22 -23
7.
Detailing of Study results &
Achievable Benefits
24 - 28
8.
Project Summary
29 -30
9.
Executive Summary, Energy
Balance & Investments
31 - 33
10.
Benefits of UPTECH Energy
Efficiency Measures
34 - 35
11.
Balance Sheet Analysis
36 – 38
12.
Calculation sheet for capacitance
additions
40 - 41
3
EE Report for Patwari Steels P ltd
1.0
INTRODUCTION
Patwari Iron & Steel P Ltd. is located in Fatuah, near Patna in Bihar State.
The unit has been selected as one of the sites under SBI Project Uptech
Energy Efficiency Programme, in Steel Rerolling Mills. The Company is a
Private Limited Company and headed by Technocrats. The Management of
the Unit is forward looking and highly Energy Efficiency conscious. Several
measures have already been undertaken by the Unit by way of Power
Factor improvement. Though the Management recognizes the immediate
necessity of having trained and qualified Technical Staff, they are unable
to get such staff due to the sudden upsurge in the Steel Industry where
the capacities have more than tripled in the past two years.
The unit is equipped with two numbers of three zone reheating furnaces
(two zone fired & one zone unfired) each and a cross – country rolling mill
with 9 stands driven by a single AC motor of 800 hp. The Unit has already
installed additional Motors to streamline the rolling as well as increase the
capacity of the rolling mills to 9 tph. The new system will go on stream as
soon as they receive the Power from the BSEB.
The power supply at 11 kV is from Bihar State Electricity Board (BSEB).
The unit has a Bore well for make up water supply and closed loop water
recirculation system with a cooling tower. The Unit has its own Induction
Furnaces, which make the ingots required by the Rerolling Mills, and a
foundry unit making grinding media alloy steel balls
BRIEF DESCRIPTION OF COMPANY’S FINANCIALS:
Income as on March 31, 2006:
Rs 17.68 Crores
Expenditure as on March 31, 2006:
Rs 17.45 Crores
Profit after tax as on March 31, 2006:
Rs 21.11 lakhs
Expenditure on power and fuel:
Rs
5.60 Crores
IMPACT OF PROJECT UPTECH INTERVENTION
Expected reduction in expenses on power and fuel:
Rs 10.25 Lakhs
Expected increase in income due to reduction in scale loss:
Rs 57.00 Lakhs
Expected increase in income due to increase in Production:
Rs 3.00 crores
4
EE Report for Patwari Steels P ltd
5
EE Report for Patwari Steels P ltd
1.1
Facilities
The specifications of major facilities installed in the unit are as listed below:
a)
Reheating Furnace
Sl.
No.
Parameters
Units
1.
Type of furnace
2
2.
No. of zones
3.
Inside length of each
Zone
4.
Inside
furnace
5.
Area of hearth
6.
Actual
achieved
7.
Present
productivity
of hearth
8.
Specific fuel
Consumption
9.
Charging System
PHZ/HZ
/ SZ
width
of
capacity
Parameters before Project
Implementation
Parameters after Project
Implementation
Pusher type, pulverized coal fired, Pusher type, pulverized coal fired,
end charged and side discharged
end charged and side discharged
3
3
M
21
PHZ – 7m
HZ – 7m
SZ – 7m
21
PHZ – 7m
HZ – 7m
SZ – 7m
m
2
2
40
40
tph
4-5
8.8 - 10
Kg/sqm
/hr
150
220
90 -100
85-90
Manual with ingots supplied by
tractors from the Induction
Manual with ingots supplied by
tractors from the Induction
Sq m
kgpt
6
EE Report for Patwari Steels P ltd
Sl.
No.
Parameters
10.
Scale loss in furnace
11.
Furnace pusher:
Units
(%)
Parameters before Project
Implementation
Parameters after Project
Implementation
Furnaces integral with the
Company and also from the
market
Furnaces integral with the
Company and also from the
market*
*It is expected that the Unit will
introduce Hot Charging of ingots
as soon as the 2nd furnace is
modified and made operational.
4-6
1.8 - 2
Electro- mechanical 30 hp
Electro- mechanical 30 hp
Cycle time
Min
---------------
---------------
Stroke
Min
4 feet
4 feet
12.
Furnace discharge
mechanism
Manual extraction from furnace, Mechanized ejection system
overhead chain trolley transfer to
mill
13.
Contour of roof
(arch/
Flat)
Arch
Arch
14.
Flue Duct Xn
dimensions
hxw
(mm)
900 x 600
900 x 600
15.
No. of charging rows
One
One
16.
Residence Time of
charge
4 -4.5
3.5 - 4
17.
Type of fuel
PulCoal
PulCoal
Nos.
hrs
FO/NG/
PulCoal
7
EE Report for Patwari Steels P ltd
Sl.
No.
Parameters
Units
Parameters before Project
Implementation
Parameters after Project
Implementation
4500
4500
Local, 100mm dia
Local, 100mm dia
Two (SZ, Front Firing)
Two (HZ, Top Firing)
Two (SZ, Front Firing)
Two (HZ, Top Firing)
NA
NA
/ PG
18.
CV of fuel
19.
Burner details
Kcal /
kg
Type & Make
Quantity
Nos.
Turndown ratio
20.
Air pipe dia HZ
mm
Header 8”
Downcomers 2 x 4”
Lagging - No
Valve dia –Butterfly, 4”
Header 8”
Downcomers 2 x 4”
Lagging - Yes
Valve dia –Butterfly, 4”
Hot recirculation gases:
Header 8”
Downcomers 2 x 4”
Lagging - Yes
Valve dia - Butterfly, 4”
Air pipe dia SZ
mm
Header 8”
Downcomers 2 x 4”
Lagging - No
Valve dia - Butterfly, 4”
Header 8”
Downcomers 2 x 4”
Lagging - Yes
Valve dia - Butterfly, 4”
Furnace refractory
8
EE Report for Patwari Steels P ltd
Sl.
No.
Parameters
Units
Parameters before Project
Implementation
Parameters after Project
Implementation
Unknown - Al2O3 + Insulation
blocks
45% Al2O3 + Insulation Blocks+
50mm thk ceramic fibre block
450 mm
450 mm
Unknown - Al2O3 + Insulation
60% Al2O3 + Insulation
Unknown
900
Unknown
550 Ceramic Fibre Blocks & Board
900 x 600
1200 x 600
Recuperator
Location
Below ground in flue duct
Inside furnace at charging end of
furnace, and recirculation system
from the duct
Recuperator Type

Side walls
Total thickness
mm
Hearth
Total thickness
mm
Roof
Chimney Base
Flue Duct Size
21.
22.
23.
mm
Waste gas entry temp
o
Combustion air
preheat at recuperator
o
Combustion air
preheat at burners
o
Coal conveyor air
blower
C
C
C
Hp/kw
Quantity
Nos.
Capacity
Nm /
hr
3
MS shell & tube type
550
140

MS shell & tube type
750
350 - 450
120 - for soaking zone & heating 300 - 400 after lagging the pipes
zone
15
10
2
2
Unknown -for heating zone & 2500 nM3/hr
Unknown for soaking zone
9
EE Report for Patwari Steels P ltd
Sl.
No.
Parameters
Units
Parameters before Project
Implementation
Parameters after Project
Implementation
350 mm WG Pressure
Delivery pressure
mm
WC
Unknown for heating zone
Unknown for soaking zone
24.
Delivery pipe dia
mm
150
25.
Chimney - Total
height
- Dia at
base
- Ht of
base
- Dia at
top
m
mm
m
mm
m
30
1500
1.5
450
26.
Length of flue duct
m
27.
Furnace
instrumentation:
Hot air temperature
gauges
Temperature
indicators for heating
and soaking zones
Manual/electric airfuel ratio control
Flue gas analyzer
Air & oil pressure
gauges Automation
7.5
Nil
Thermocouples fitted at
a) Soaking Zone
b) Heating Zone
c) Hot air at burner
d) Hand held flue gas analyzer
to
measure
furnace
atmosphere
e) In the second phase the
flue gas analyzer to be an
on-line apparatus, which
will be integrated with the
thermocouple sensors to
10
EE Report for Patwari Steels P ltd
Sl.
No.
Parameters
Units
Parameters before Project
Implementation
system
b)
Parameters after Project
Implementation
control coal feed
Rolling Mill
Sl.
No.
1
Description
Units
Roughing Mill – 1
Quantity
18”
No.
Type
Motor
Flywheel
6
Crop Shear
7
Stationery wall tilters
Quantity
Hp
T
8
800
--------------Fabric
Rpm
Nos
712 Rpm (Motor)/ 220 RPM (Mill)
2 – 1No for front end and 1 No
for back end cutting
Nil
Nos.
Location
Rotary Shear
One
3-hi open
Type of roll neck
bearing
Mill Speed
Parameters
Nil
Nil
Nos
TMT Cooling Box
One
Yes
11
EE Report for Patwari Steels P ltd
Sl.
No.
Description
Quantity
Units
Nos.
Location
9
Parameters
One
After Stand Nine
Cooling Bed
Quantity
Length
No.
m
Type
Capacity
1
55
W channel
T
2
12
EE Report for Patwari Steels P ltd
c)
Electrical Facilities
Sl.
No.
Description
1
Source of power
supply
2
Incoming
voltage
3
Transformer
Ratings
Voltage Ratio
Units
Parameters before
Proj
Implementation
Parameters
after Proj
Implementation
Bihar State Electricity
Board (BSEB)
kV
KVA
kV
Type
11
1000
11 KV/ 440 V
Star Delta, outdoor
duty
4
Total connected
load (HT & LT
load inclusive)
kVA
680 (approx)
5
Contract
demand
kVA
680
6
Maximum
demand
kVA
715
7
Average power
factor
8
HT & LT
Capacitor Bank
0.98
KVAr
Nil, LT - 380 KVAr for
Mill Motor
13
EE Report for Patwari Steels P ltd
Sl.
No.
Description
Units
Installed
9
Parameters
after Proj
Implementation
150 kvar for
auxiliaries
Roughing, intermediate & Finishing Mill Drive
Quantity
10
Parameters before
Proj
Implementation
No
1 Common for all the
nine stands
Type
AC Slip Ring
Induction Motor
(SRIM)
Ratings
800 hp, 415 V, 1400
A,
Major auxiliary
drives (LT)
Air Blowers
KW
KW
3 x 15
Oil pump
KW
Nil
Billet Pusher
KW
18.65
Cooling bed
chain transfer
KW
15
Crop shear
KW
2 x 3.75
Water pump
KW
15, 22.5
ID fan for
chimney
Nil
14
EE Report for Patwari Steels P ltd
Sl.
No.
Description
Other like oil
heaters,
conveyers,
hoist, Bore well
pump motor,
machine shop
man coolers
etc.
11
Lighting:
Type of
luminaries
12
Lighting:
Power
Consumption
Switching
arrangements
Units
KW
Parameters before
Proj
Implementation
Parameters
after Proj
Implementation
NA
2×400,17×250W
HPMV & HPSV lamps
,8×100W Filament
type lamps,6×40W
Fluorescent Tubes
kW
10KW (approx)
Manual
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EE Report for Patwari Steels P ltd
1.2
Input Stock & Product Mix
The mill is using Ingots of 3” x 4” x 1.3 m as input material weighing
approx 78 kgs (average). The product mix of the unit is TMT Rounds of
different sizes:
2.0
METHODOLOGY
M/s RPL Engineering Consultancy P Ltd, the empanelled consultant of SBI
Project Uptech, conducted the Energy Efficiency study.
As part of the Energy Efficiency study, M/s RPL Engineering Consultancy P
Ltd was asked to study the Rerolling mills reheating furnace and suggest a
method for reducing the scale losses in the furnace and the Mills. M/s RPL
Engineering Consultancy P Ltd was also asked to suggest a method to
reduce the specific fuel consumption.
For the study a comprehensive energy, process and design audit of the
selected unit was carried out by our team of experts with an objective to
gauge end-use energy efficiency and identification of system & design
deficiencies vis-à-vis energy savings opportunities, and to short-list costeffective investment options.
It was found that the Unit had carried out substantial energy saving
measures by way of improvement of the power factor of the electrical
system. In general the power factor hovered around 0.95- 0.99, which
was considered sufficient. The Unit has adopted Static Power Factor
Correction System, which was considered as more efficient than Bulk
Power Factor Correction System, but the final tuning of the system had
not been carried out, and is recommended by this team. The load on the
main mill motors reaches more than 2500 amps instantaneous loading for
a fraction of second and 900 amps continuously for more than 30
seconds. It is suggested that the capacitors of 320 KVAr be enhanced to
600 KVAr in two sections of 300 KVAr each, and this should be provided
with suitable controls to cut - in / out the capacitors according to the load
on the motor for more than 8 seconds. This is considering an average
requirement of 1700 HP for more than 6 seconds per bar rolled
The Unit has provided 150 kvar capacitors in their auxiliary & utility
systems for Power Factor Correction. Since Control of Energy Costs can be
done only if sufficient information is available, it is suggested that check
meters to display the power factor, energy consumption and phase
imbalance be installed at each panel. For this the Unit should be divided
into separate cost centres and the provision of the above meters will help
in determining the cost of production at each centre, and suitable
measures can be introduced to reduce the cost to the maximum extent
possible
In order to reduce their future cost of cabling and preventing losses
through use of cables, we recommend that the Unit installs a ring main of
16
EE Report for Patwari Steels P ltd
4 wire bare aluminium cables at + 6.5 m above ground level along the
entire lengths of their sheds. With this the Unit will have the advantage of
not having to invest in costly cabling to and from the Main Distribution
Panel situated at one end of the Unit, each time a new machine is
installed.
Next a detailed baseline measurement study to determine the realistic
baseline with respect to the scale losses in the furnace as well as in the
mill was made. It was found that the total scale loss was between 4.4 to
5.6%. We have suggested the following measures to reduce the scale loss
and improve the specific coal consumption per tonne of steel rolled: 1. Fit thermocouples (R Type) at the heating and soaking zones, with
digital read out indicators.
Action: Patwari Steels
2. Fit thermocouples (K Type) at the end of the preheating zone, with
digital read out indicators. This will give the temperature of the flue
gases exiting the furnace.
Action: Patwari Steels
3. Change the blowers to give 3200 Nm3/ hr air at 350mm pressure
for conveying the pulverized coal to the burners. The HP of the
motor would be around 5.00. Max. size of blower motor to be
installed 7.5 HP
Action: Patwari Steels
4. The burners should have a screw type impeller to direct the
pulverized coal into the furnace in a spiraling motion. This will help
in better combustion of the coal
Action: Patwari Steels/ RPLEC
5. Ensure a rich mixture of coal /air by decreasing the stoichiometric
air required for full combustion. The recirculation of flue gases from
flue ducting to the RHF should be done using this third blower, the
air being injected into the furnace at the heating zone. This will
ensure almost complete combustion of the unburnt coal/ carbon
monoxide just before the preheating zone and at the same time
ensure required temperature of 1150 -1200 0C temperature of the
ingot at the end of the heating zone of the furnace. The
temperature of the flue gases exiting the furnace should not be less
than 750 0C. The control of the recirculation gases should be done
by monitoring the CO percentage at the end of the preheating zone
approximately at the entrance to the flue duct. Part of the
recirculatory flue gases should be directed to the point where the
pulverized coal drops into the air conveyor for the heating zone.
The effect of such an action would increase the temperature of
17
EE Report for Patwari Steels P ltd
air/coal mixture to around 450 to 500 0C, and at the same time
ensures fuller burning of the unburnt gases due to recycling of the
unburnt fuel into the furnace. It also creates a reducing atmosphere
in the furnace in the hotter regions, leading to virtually no scaling of
the ingots. The above action will increase the Energy Efficiency of
the furnace, reduce the scale losses, reduce the specific coal
consumption and ensure more uniformity in the heating of the
ingot, which will go a long way to supply a quality product.
Action: Patwari Steels
6. The high temperature given to the combustion air will ensure an
increase in the flame temperature to around 1700 0C, almost as
much as obtained in furnace oil.
7. Fine tuning of the implementation of the above recommendations
will be done under the guidance of the expert team. The cost of
implementation of the above is not expected to be more than Rs
12,50,000, whereas the benefits are expected to be as follows:
a. Reduction in scale loss: from 4.5% to 1.8% - 30 kgs per
tonne of steel charged. On a conservative estimate of
reduction in scale loss of only 2%, 60 tonnes /day production
for 250 days of operation per year, for an annual production
of 15000 tonnes, this works out to a saving of 2.0 % @ Rs
19000 per tonne, it works out to Rs 57 lakhs per year
b. Decrease in specific fuel consumption from 100 kgs per tonne
to 85 kgs/ tonne, or Rs 67.50 per tonne steel rolled @ Rs
4.50 per kg of coal, which works out to Rs 4050 per day and
Rs 10,12,500 per year
c. More uniform heating of ingot to 1100 0C to ensure entry
temperature to the TMT Box at > 900 0C. This would be
made possible only after commissioning the second motor for
the Intermediate Stands and the finishing mill train
d. Increase in capacity of the furnace by 2 tonnes per hour,
providing the mill has the requisite capacity to take the
additional throughput from the furnace. Considering a net
margin per tonne of sold steel of Rs 3000 and considering
10000 tonnes per year extra production, this works out to Rs
300 lakhs/y additional earnings
8. The temperature profile of the furnace to be maintained as follows:
a. End of preheating zone and start of heating zone: 650 –
8000C
b. End of heating zone and start of soaking zone: 1200 0C
c. Discharge end or end of soaking zone of furnace: 1100 0C
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EE Report for Patwari Steels P ltd
9. The analysis of the furnace atmosphere should be as follows:
a. CO: 85 – 100 ppm at exit of furnace
b. CO: 200 to 500 ppm at heating zone & soaking zone
The above recommendations are to help the unit to improve the
performance of the unit with marginal or no investments and that only
through some minor debugging.
19
EE Report for Patwari Steels P ltd
Damper
Air from
Blower
Pulverized Coal
Dilution air
Chimney
Pulverized Coal + Hot
Air to burners
Flue Gas Recirculation System
Recommendation for Reduction of Scale Loss
1100C
7m
1200C
850C
7m
16 m
Furnace Temperature Profile
20
EE Report for Patwari Steels P ltd
Depending upon the Unit’s logistics, Product Mix and the scale of
operation the ideal operating parameters are developed over and above
the Baseline and the achievable parameters or the Bench Marks are set as
detailed below:Parameters
Base Line
Project UPTECH
Bench
Marks
RHF Capacity
5 tph
7.5 tph
11.5 tph
Area of hearth
37.80 sqm
37.80 sqm
37.80 sqm
RHF Hearth
Productivity
132.28
kgs/m2/hr
198.40 kgs/m2/hr
300
kgs/m2/hr
4.5 tph
9 tph
93 %
97.4 %
97.85 %
Scale loss in RHF
3%
1%
0.85 %
End Cuts Losses
3%
0.8%
0.8 %
Mill Scale Losses
1%
0.8 %
0.5 %
60 %
80 %
90 %
85 kgpt
85 kgpt
Item
RRM Capacity( for
multi piece rolling)
Overall Yield
Mill Utilization
Specific Fuel
Consumption (SFC)
100 kgpt
SFC expected after
implementing Hot
Charging
Specific Power
Consumption
a)
45 kgpt
kWh/t
100 kWh/t
95 kWh/t
Pre-feasibility and feasibility assessment is the next key step to
determine EE road map and corresponding project plan (PP) for the
unit. The assessment includes:
I.
Technical issues both at the plant engineering and HRD
levels, namely plant layout & design considerations including
scope and limitations for improvement; energy savings and
control potential based on current practices; technology and
vendor availability and the extent of training required to run
and maintain the relatively high-end EE technologies.
II.
Cost, investment and financial issues namely economic &
commercial viability (attractiveness of return on investment),
access to low cost capital, cost benefit analysis (savings – to
21
EE Report for Patwari Steels P ltd
– investment ratio (SIR)), internal rate of return (IRR), debt
service coverage ratio (DSCR), - financing scope - whether
to retrofit the existing equipment or completely install a new
one, and the financing pattern - whether short term or long
term.
22
EE Report for Patwari Steels P ltd
3.0
ACTUAL STUDY - Observations and Suggested Measures
During the Energy Audit and BL measurement studies, the Consultant, PG
Ittyerah made the following observations and suggested corrective
measures.
3.1
Reheating Furnace Area
3.1.1 Observation
The furnace has been provided with a total four nos. of burners (two nos.
in soaking zone and two nos. in heating Zone). The furnace is equipped
with a locally fabricated recuperator. During study it was observed that
the flue gas off-take temperature is around 350 0C, and the hot air
temperature at the recuperator outlet is around 180 0C. The furnace is
supplied with two numbers of blowers (one in each zone). The heating
zone is equipped with blower having air delivery capacity of (unknown)
Nm3 per hour and soaking zone is having (unknown) Nm3 per hour.
The scale formation was found to be very high (4.4 – 5.2%) and specific
fuel consumption was also on higher side (>100 kgpt).
The readings for various parameters as measured are given below:
Sl.
No.
Parameter
Measured
Readings
Envisaged
1.
Best specific coal (kgs/tonne)
>100
85
2.
Best 6 hours of most
production per hour (Tonnes)
5
8
3.
Average heating zone
temperature (0C)
850 – 900
Should be Around
-1200 0C
4.
Average soaking zone
temperature (0C)
1200
Should be Around –
1100 - 1150 0 C
6.
Preheat air temperature (0C)
180 0C
7.
Scale Loss (%)
4.4 – 5.2
8.
Breakdowns (%)
>15 %
350 - 4500C
Should not exceed
1.5 %
5 % excluding
power outages
Flue gas was also analyzed and the readings measured at different times
are as under.
Flue gas analyzer readings
23
EE Report for Patwari Steels P ltd
Heating zone
Chimney
Pre-heating
Zone
(Backend)
O2%
16
12
14
CO2%
12
12
12
CO ppm
10
0
0
Prs mBar
Not measured
Not
measured
Not measured
45
30
40
Not measured
Not
measured
Not measured
850
200
450
Parameter
X Air %
SO2 ppm
Flue 0C
Suggested Measures
In order to achieve a reduction in the scale losses it is necessary to reduce
the residence time in oxidizing atmospheres when temperatures are
higher than 7600 C in the furnace. It is proposed that the operating
practices at the RHF be changed to achieve indices as follows: a)
Scale loss less than 1.5 %
b)
Unit fuel consumption at less than 85 kgs/t charged, are fulfilled.
The proposed furnace operations should be fully automated in order to
achieve the desired technical parameters and at the same time remove
the dependence on individuals. The parameters that would be selected, as
reference points for controlling the combustion and heating of the charge
will be:
a)
Temperature at discharge door – 1100 – 1150
thermocouple
b)
Temperature at heating zone – 1150 – 1200
thermocouple
c)
Flue gas off-take temperature – >750
thermocouple
d)
Flue gas analysis excess air % - oxygen 2 – 4 %, CO 200-400 `% &
CO2 9-12% - Sensor used – hand held FG Analyzer
e)
Furnace pressure – 1 – 2 mm WG – Sensor used – Pressure probe
f)
Stoppages due to mill breakdowns – greater than 5 minutes should
be noticed and coal feed decreased at the heating zone first, and
coal feed increased at soaking zone, and if outage is more than 15
minutes the blowers should be run at much lower speed and the
coal feed should be decreased gradually at both zones
0
0
0
C – sensor used –
C – Sensor used –
C – Sensor
used –
3.1.2 Observation
24
EE Report for Patwari Steels P ltd
The excess air level is very high.
Suggested Measures
The blower speed should be decreased until flue gas analyzer reads 3 6% excess air
3.1.3 Observation
The recuperated hot air temperature was very low.
Suggested Measures
The system suggested by M/s REPLEC does not require any recuperator,
as the air is directly heated by the exiting flue gases. The provision of
dilution air to control excess air temperature should be utilized in
conjunction with damper opening at the chimney
3.1.4 Observation
The furnace productivity @ 120 kg / sqm/ hr from a hearth area of about
37.80 sq mtr is considered very low
Suggested Measures
The productivity has to be increased to 220 Kg / sq mtr/hr. For this the
hearth area to be reduced and/or specific heat input has to be increased.
It is suggested that the Unit refurbish the non running RHF to
meet the above suggested parameters
3.1.5 Observation
The scale loss was at a high of 4.4 – 5.2%
Suggested Measures
The furnace atmosphere & residence time have to be so adjusted that the
formation of scale is inhibited. The actions already suggested above will
automatically reduce the scale. It is expected that the scale loss would not
exceed 1.45% of charged steel tonnage assuming production @ 8 t/hr, 18
hrs/day and 250 working days/year, i.e. 36000 tpy
3.2
Rolling Mill Area
3.2.1 Observation
Overall housekeeping in the unit is not satisfactory and requires efforts for
betterment.
Suggested Measures
The unit should earmark the space for rolls, guides and other equipment.
Storage racks for rolls & equipment should be made and stacking done
accordingly. The templates for various roll grooves / guides etc should be
periodically checked and master templates preserved at a suitable
location.
25
EE Report for Patwari Steels P ltd
3.2.3 Observation
The cooling of rolls is inadequate and fire cracks were observed on the
used rolls.
Suggested Measures
Augmentation of roll cooling water quantity & pressure should be done by
installing water header ring and nozzles for effective cooling. The cooling
water spray should be directed only on the pass being used for the current
rolling
3.2.4 Observation
The current drawn with multiple-piece rolling often exceeded the drive
motor rating
Suggested Measures
This would be remedied after the bifurcation of the roughing stands and
intermediate stands by provision of additional motors
3.2.5 Observation
Mill scale accumulated near the entry guides of various stands was
observed which was rolled along with the stock during rolling.
The fixation of entry delivery guides was getting disturbed during rolling
and their readjustment took time thus increasing the idle time & lowering
the overall mill utilization.
Suggested Measures
The unit should make trenches 850 mm deep on both the sides of existing
stands with adequate slopes so that the water flows to the collecting
cooling water pit clearing the mill scale along the guides and shall also
result in proper fixation of guides due to access to setting.
3.2.6 Observation
The adjustment of stock size and roll gaps during the mill running was
done through the screw down mechanism without loosening the chocks.
This was resulting in higher transmission losses.
Suggested Measures
The rolling gaps and stock sizes should be adjusted only after loosening
the roll neck chocks to have effective settings. The tightening / loosening
of screw down mechanism without chocks loosening create extra
vibrations and loads.
3.2.7 Observation
26
EE Report for Patwari Steels P ltd
The connecting spindles (cotter type) between the rolls from stand to
stand had different inclinations, and were having vibrations.
Suggested Measures
The unit should identify rolls sets with almost equal diameters to be used
for rolling so that the spindle inclinations are minimized and reduce the
transmission losses. The unit should adopt universal type spindles /
couplings.
27
EE Report for Patwari Steels P ltd
4.0
PROJECT SUMMARY
The following is the project summary which gives improvement in
operational parameters through equipment process and design upgrade
highlights operation parameters, corresponding investments, annual EE
savings, cost-benefit analysis of EE investments.
4.1
Performance Parameters
Various operation parameters during the studies by REPLEC have been
taken as current practice. Baseline parameters are the parameters
measured by REPLEC. Project parameters indicate the values which the
unit can achieve with changes in the logistics and adopting the EE
measures.
Practice
Parameters on which performance is measured
Product
ivity
Utilizat
ion
(tph)
(%)
5
65
>100
Project
Case
8
80
BENCH
MARK
9.5
90
Current
Practice
Coal
(kg/t)
Power
Yield
(%)
End
Cuts,
Misro
lls
etc
(%)
110
4.5 5.6
6
88
<85
100
1.8
4.5
93.7
<60
(with
Hot
Chargi
ng)
95
1.2
3
95.8
(KWh/
t)
Scale
loss-
(%)
The norms projected and benchmark for burning loss and mill scale etc.
for the unit are as per standard audit practices.
This unit is rolling mild steel and material discharge temperature is
12000C which is on the higher side, we are suggesting the material
discharge temperature at 1150 0C, but the material should be well soaked
with difference in temperature between top and bottom of ingot to be
within +/- 100C. It was observed during study the finishing temperature
was way below the 900 0C required to get quality TMT. For this the
discharge temperature should be within the norms of 1050 0C – 1150 0C.
Also the rolling speed at the intermediate stands should be increased and
28
EE Report for Patwari Steels P ltd
Hot
Charging
additiona
Mill Motor
the end cutting after stand #1 should be speeded up by using automatic
shears instead of manually fed crop shear.
Description
Before Project
After Project
Ingot / billet dimensions
Length, Meters
1.8
1.8
80 x 80
80 x 80
1200 (non uniform
soaking)
1150 (properly
soaked)
8-10
5
20
20
mm x mm
Operating Parameters
Hot Discharge Temperature, C
Mill BD plus idle time, %
Mill Operational Hrs per day
As per Standard Audit
Min
Max
Min
Max
Burning loss total %
4.5
5.6
1.0
1.8
It is to be noted here that the projected norms and benchmark is
very much dependant on material input size and different
operating practices such as Material discharge temperature,
percentage mill breakdown (or total mill utilization) and no. of
operating hours etc.
The mill utilization of 65 % (average) and rolling rate of 5 tph have been
taken on the basis of actual studies conducted by REPLEC team during
Energy Audit study
However, the achievable capacity of the mill as 9.0 tph is taken on the
basis of reduction of idle time after project implementation and improved
Furnace operations, and connecting the additional motors for the
Intermediate Stands and Finishing Train. The project envisages
Upgradation of existing facilities with EE measures and installation of a
new Intermediate mill motor & finishing train
29
EE Report for Patwari Steels P ltd
EXECUTIVE SUMMARY OF ENERGY AUDIT
The energy balance sheet of the unit for Baseline and Uptech is presented
below:
Energy Audit Summary
Operational Parameters
Baseline
Uptech
100
85
Scale loss, (per MT of throughput), %
4
1.5
Through put rate (tonnes per hr), tph
5
8
1200
(improperly
soaked)
1150
(properly
soaked)
100
80 (after
change of
refractories)
O2 in flue gas, of (%)
16
3–4
CO2 in flue gas, (%)
12
13
CO in flue gas, (ppm)
10
100
Excess air, (%)
30
12- 18
Exhaust gas temp at furnace backend, in (0C)
350
700
Exhaust gas temp at stack, out ( C)
200
200
Air preheat Tf (0C)
180
550
Fuel preheat Tf (0C)
NA
400
Thickness of refractory lining, x (m)
0.450
0.450
Calorific value of fuel, NCV
4500
4500
450
383
Sensible heat of fuel (MCal/t)
1
1
Sensible heat of air (MCal/t)
45
40
Heat of formation of scale (MCal/t)
40
16
531
440
Steel, (MCal/t)
185
185
Scale, (MCal/t)
12
4
Dry exhaust gas, (MCal/t)
84
84
Water vapour, (MCal/t)
10
10
Fuel consumption (per MT of throughput), Kg
Furnace Measurement
Rolling Temperature, Hs (0C)
Avg, Skin Temperature, ts (0C)
0
Energy Input (Thermal)
Fuel (MCal/t)
Total
Energy Output (Thermal)
30
EE Report for Patwari Steels P ltd
Energy Audit Summary
Operational Parameters
Baseline
Uptech
5.5
6
3
3
40
36
Total
339.5
328
Other (difference), (MCal/t)
190.5
132
Efficiency
64%
74.50%
Heat loss due to radiation & Convection,
(MCal/t)
Heat loss due to opening, (MCal/t)
Heat loss due to non continuous operation
(MCal/t)
4.2
Investments (Rs. Lakhs)
During Energy Audit study conducted by REPLEC, a number of suggestions
for debugging have been given to the unit for performance enhancement
However the summarized concept for both EE measures and measures
with expansion are as given below.
(Rs in Lakhs)
Brief Description
Reheating Furnace
Rolling Mills
RHF:
Mill,
Energy
possibilities
Mill are:
Achieving
furnace Piping works: Rs 50,000
productivity
of Flue gas analyzer: Rs 70,000
220 kg/m2/hr
Thermocouples with indicator
Attaining hot air / controller: Rs 25000
4500C
Stainless steel blower for hot
flue gases: Rs 2.50 lakhs
Variable speed drives
blowers: Rs 1.25 lakhs
1.
Provision
of
antifriction
bearings for rolls
2.
Provision
universal
spindles
3.
Automatic end
cutting machines
4.
Wall tilters
Stand 1
for
Automation System: Rs 3.50
lakhs
On line Flue gas analyzer: Rs
3.50 Lakhs
Eff
in
of
at
5. Automatic cooling
bed
Total Investment required
for EE: Rs 12.20 lakhs
But the above do not
have attractive payback periods
4.3
Annual Energy Efficiency Savings (Rs Lakhs)
In view of the project, the net annual EE savings and productivity benefits
exclusively to EE measures have been worked out as under.
31
EE Report for Patwari Steels P ltd
(Rs in Lakhs)
Item
Investment Required
Expected Savings per
annum
Reheating Furnace
12.20
1. From scale loss
reduction:
@2%
reduction and @ Rs
19000 /t of steel, and
60
tonnes
steel
produced per day and
250 days working per
annum: Rs. 57 Lakhs
2.
From
increased
production from 6 tph
to 8 tph: Rs 3 crores @
Rs 3000 margin per
tonne of steel
3. From decreased fuel
consumption from 100
kgpt to 85 kgpt, and @
Rs 4500 pt of coal: Rs.
10.25 lakhs py
Total benefits: Rs
367 Lakhs per year
4.4
Costs-Benefit Analysis of Energy Efficiency and Investments
Since the investment amount is negligible – Rs 12.20 Lakhs against
expected benefits from Energy Efficiency Audit recommendations – Rs 367
Lakhs, it is meaningless to project the financial indices as the benefits are
overwhelming
32
EE Report for Patwari Steels P ltd
5.0
SUMMARY, CONCLUSIONS & FUTURE COURSE OF
5.1
Conclusion & Future Course of Action
ACTION
M/s Patwari Steels P Ltd has always been a progressive unit. They have
been doing various EE improvements in the mill and furnace over the last
3 to 4 years albeit in a piecemeal manner. The proposed Technical &
Financial Plan is a comprehensive energy efficiency roadmap that looks
into the mid and long-term future of the company. As it can be seen, the
proposed plan employs unique high efficiency flue gases recirculation
technology package. It is necessary for the success of the Project; the
Unit’s Management conducts training programmes for its shopfloor staff &
workers on the benefits accruing to the Company from the Energy
Efficiency measures to be introduced. Every sign of opposition to the
Energy Efficiency programme must be thoroughly examined by the
Management before abandoning the measures that would greatly benefit
the Company.
It is necessary to thoroughly overhaul the present shopfloor
supervision practices and introduce dynamically oriented
supervisory system to implement systems never before attempted
in rolling mill reheating furnaces, but which are common in
pulverized coal fired boilers. Results were demonstrated to the
PSPL Management, but to make it sustainable, there has to be
cooperative involvement in the proposed changes in operational
practices. Until the system is set, the Management & the
Supervisory staff have to be on their toes, as the benefits of the
recommendations are so huge that M/s PSPL can look forward to a
bright future with the cutting edge technology in their grasp.
33
EE Report for Patwari Steels P ltd
5.2
Balance Sheet Analysis
Since the amount required to be invested for implementing Energy
Efficiency measures is very much insignificant the Unit may want to
finance the same from internal accruals.
REPLEC has examined the Balance Sheet of M/s. Patwari Steels P Ltd
for the year 2004 – 05. Weightages have been assigned to the key
financial ratios to determine the relative strength (extent of credit
worthiness) of the Unit with respect to on-balance-sheet financing.
Balance Sheet Analysis
Financial
Ratio
Description
Formulae
Net Worth
Taking the total assets and Total Assetssubtracting
the
total Total Liabilities
liabilities
calculate
net
worth of a unit. Higher net
worth can increase the
comfort
level
of
Bankers/Fis.
Return on
Investme
nt (Before
Tax), RoI
%
Taking the PBT and dividing
by (current assets-current
liabilities+
secured
&
unsecured loans) calculate
RoI.
Higher
RoI
also
increases the comfort level
of Bankers/Fis.
Return on
equity
(ROE), %
Return on equity (ROE) is
one of the most important
indicators
of
a
unit’s
profitability and potential
growth. It is calculated
using the DuPont model:
Fixed
Asset
Turnover
Ratio
Asset Turnover Ratio is a
measure of how efficiently
a unit uses its assets (fixed
or total) to generate sales.
It is the ratio of sales to
total assets.
Total
Asset
As
above.
The
asset Sales/Total
turnover ratio tends to be
PBT/(current
assets-current
liabilities+
secured loans+
unsecured
loans) X100
Net Profit
Margin: Net
Income ÷
Turnover
Asset
Turnover:
Return on Equity = Net Turnover ÷
Profit
Margin
x
Asset Assets
Turnover
x
Equity Equity
multiplier:
Multiplier.
Assets ÷ Equity
Asset Turnover
= Sales
(Revenue) ÷
Fixed Assets
Weigh
t age
Scor
e
10
4
5
3
15
10
5
3
5
2
34
EE Report for Patwari Steels P ltd
Turnover
Ratio
inversely related to the net Assets
profit margin; i.e., the
higher
the
net
profit
margin, the lower the asset
turnover. It should always
be seen as a combination
of Asset Turnover Ratio and
Overall Profitability Ratio
given below.
Overall
Profitabilit
y Ratio
Overall Profitability Ratio is
simply the after-tax profit a
unit generates for each unit
of investment.
PAT ÷ (net
worth +
secured loans
+ unsecured
loans)
15
12
Current
Ratio
Also called working capital
ratio, it measures the
extent to which current
assets are available to
meet current liabilities (due
within
the
next
12
months). The Current Ratio
indicates whether the unit’s
business
has
ample
working capital i.e. the
excess of current liabilities
over current assets used to
meet
short-term
obligations, quickly take
advantage of opportunities,
and qualify for favorable
credit terms. However, a
very high ratio (greater
than
2.0)
indicates excessive current
assets in the form of
inventory, and underemplo
yed capital.
Current Ratio =
Current assets
/ Current
liabilities
10
6
Interest
Coverage
Ratio
The interest coverage ratio
is a measurement of the
number of times a unit
could make its interest
payments with its profits
before interest and taxes;
the lower the ratio, the
higher is the unit’s debt
burden.
PBIT (profit
before interest,
depreciation
and taxes) ÷
Interest
10
7
35
EE Report for Patwari Steels P ltd
Debt to
Equity
Ratio
Debt to Equity Ratio is also
referred to as Debt Ratio,
Financial Leverage Ratio or
Leverage Ratio. The ratio
indicates the extent to
which the business relies
on debt financing. Upper
acceptable limit of the debt
to equity) ratio is usually
2:1, with no more than
one-third of debt in long
term.
A
higher
Ratio
indicates possible difficulty
in paying interest and
principal while obtaining
more funding.
Net Profit
to
Turnover
Ratio
This ratio reflects the Net Profit after
position of profits earned tax÷ Sales
on sales. Increasing and
higher ratio is indicative of
better performance.
Total
Debt to Equity
Ratio = (Short
Term Debt +
Long Term
Debt) ÷ Total
Equity
15
10
10
6
100
Balance Sheet Ranking:
65
Very Strong: Aggregate marks >
90%
Strong: Aggregate marks > 70
< 90 %
Mediocre: Aggregate marks > 50
but < 70 %
Weak: Aggregate marks > 30 but
< 50 %
Very Weak: Aggregate marks
<30%
36
EE Report for Patwari Steels P ltd
37
EE Report for Patwari Steels P ltd
Annexure 1
PATWARI STEELS P LTD
CALCULATION OF CAPACITANCE REQUIRED FOR PF IMPROVEMENT
Rolling Mills
SL NO
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
PROCESS/
LOCATION
Main mill drive
Gear oil pump
Rotary shear
Rotary shear
Lathe motor
Furnace Blower
Dispenser
Pusher
Coal Grinder
Compressor
Compressor
Mill pump
Rod cutter
Rod cutter
Conveyer
Conveyer
Pinch roller
DC roller
Drill machine
Cooling pump
Cooling pump
Cooling pump
RATING IN
HP
800
5
15
5
5
15
3
30
50
50
10
15
30
15
15
5
5
30
2
100
15
7.5
QUANTITY
1
1
1
2
6
3
2
1
1
1
1
1
1
1
1
1
2
2
2
1
2
4
TOTAL
HP FOR
THE
DRIVE
800
5
15
10
30
45
6
30
50
50
10
15
30
15
15
5
10
60
4
100
30
30
RPM
712
1500
1500
1500
1500
1500
1500
1500
1500
1500
1500
1500
1500
1500
1500
1500
1500
1500
1500
1500
1500
750
RATED
CURRENT
1057
7.5
22.5
7.5
7.5
22.5
4.5
45
75
75
15
22.5
45
22.5
22.5
7.5
7.5
45
3
140
22.5
11.5
CAPACITANCE
REQUIRED
(KVAr)
320
1.75
5.25
3.5
10.5
15.75
2.1
10.5
17.5
17.5
3.5
5.25
10.5
5.25
5.25
1.75
3.5
35
10.5
10.5
CAPACITANCE
INSTALLED
(KVAr)
380
150
38
EE Report for Patwari Steels P ltd
23
24
Submerssible
pump
Fans
7.5
3
1
5
7.5
15
1500
1500
Total
11.5
4.5
2.625
5.25
497.975
530
Due to variance in the loading of the main mill motor, it is suggested that an additional capacitance bank of 320 kvar be installed
which should cut in and cut out with any higher load that occurs for more than 10 secs
LIGHT
LOAD
RatedKV
Sl no
1
2
3
4
Name
Sodium vapour
lamp
Sodium vapour
lamp
Tube light
Welding machine
A
Rated KW
15
Quantity
0.4
2
0.8
0.25
0.04
12
17
4
1
4.25
0.16
12
16.49
Total
39
EE Report for Patwari Steels P ltd
40
EE Report for Patwari Steels P ltd
This study has been made under State Bank’s Project Uptech for SMEs
& Steel Rerolling Mill Units in Patna Circle for the States of Jharkhand & Bihar
and finalized in consultation with the units’ Directors/Partners and
Branch
Official of Financing Bank
Placed with grateful acknowledgement for the support received from
the above persons and with the sincere hope that this report will be of use to
the Unit and serve the purpose of Project Uptech
The contents of this report are recommendatory in nature, based on
actual observations/ studies made in the limited time and on the data made
available to us in the course of our visits to the Unit. The Unit’s promoters/
financing agencies may undertake further studies in any area, wherever
found necessary, while taking investment decisions.
(PG Ittyerah)
Chief Consultant
(Shri SN Prasad)
Project Officer (EEP)
SBI Project Uptech,
Jamshedpur
(Shri Kanhaiya Verma)
Asst General Manager
SBI Project Uptech,
Jamshedpur
Jamshedpur
May 21, 2007
41
EE Report for Patwari Steels P ltd