Major Project Report Final

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VISVESVARAYA TECHNOLOGICAL UNIVERSITY

BELGAUM-590014

A major Project Report on

“Debottlenecking of HMDS unit in SMS-2 (JSW Steel)”

A project report submitted in partial fulfillment of the requirement for the award of degree of

MECHANICAL ENGINEERING

Submitted by

Shivanna 2BV10ME106

Shouvik Das 2BV09ME107

Shreyas Kari 2BV09ME108

Yatiraj Singi 2BV09ME110

Under the guidance of

DR. Sanjay Kotabagi

ACADEMIC YEAR 2013-2014

KLE SOCIETY’S

B.V.BHOOMARADDI COLLEGE OF ENGINEERING AND TECHNOLOGY, HUBLI-31

(An Autonomous Institution Affiliated to VTU, Belgaum)

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KLE SOCIETY’S

B.V.BHOOMARADDI COLLEGE OF ENGINEERING AND TECHNOLOGY, HUBLI

(An Autonomous Institution Affiliated to VTU, Belgaum)

2013-2014

DEPARTMENT OF MECHANICAL ENGINEERING

Certificate

This is to certify that the project titled “Analysis of HMDS unit in SMS-2 (JSW Steel)” is a work

carried out by 1)Shivanna 2)Shouvik, 3)Shreyas, 4)Yatiraj, bonafide students of B.V.B College of

Engineering and Technology in the partial fulfillment for the award of Bachelor of Engineering in

Mechanical Engineering of the Vishvesvaraya Technology University, Belgaum during the year

2013-14. The project report has been approved as it satisfies the academic requirements in respect

of the project work prescribed for the above said course.

PROJECT GUIDE PROJECT GUIDE (JSW) HOD PRINCIPAL

Signature of Examiners

Name Signature with date

1.

2.

3

ACKNOWLEDGEMENTS

A sincere gratitude to all the kind and noble souls who blessed us and guided

us in the partial fulfilment of the course project. It gives immense pleasure in

acknowledging them; the following is the list with lots of thanks:

The Team MPB4 cordially expresses its acknowledgement to Dr. Sanjay

Kotabagi, for his guidance throughout the execution of our project and continued

support for the same.

We are thankful to our beloved Principal Dr. Ashok Shettar, for his support,

cooperation, and motivation provided to us during the field visits for constant

inspiration, presence and blessings.

It gives us immense pleasure in acknowledging our beloved HOD Dr.

P.G.Tewari, for providing us an opportunity to work on such practical based

projects.

Lastly, we would like to thank the almighty and our parents for their moral

support and our friends with whom we shared our day-to-day experience and

received lots of suggestions that improved our quality of work.

DEC 2013 MPB4

BVBCET,

Hubli

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ABSTRACT

In Hot Metal Desulphurisation Station, sulphur impurities are removed from hot

metal by a process. This metal is then taken to Basic oxygen furnace for charging.

Over a period of time this complete process got slowed. The converter at furnace

had to be kept idle for a long time. This resulted in heavy losses. The problem

has to be identified and analysis has to be carried on. Complete process steps

have to be verified for errors. Debottlenecking has to be removed from the

process so that the complete process goes on smoothly and at rapid rate. The hot

metal ladle is placed into a treatment chamber. The treatment chamber is closed

by a cover or a hood, dedusting is activated and the injection lance or the impeller

is lowered down to the final treatment position. After having injected or stirred

in the required amount of desulphurisation agents, the lance or the impeller is

retracted and the desulphurisation step is finished. Afterwards the top slag is

removed by a slag skimmer. The treatment chamber is opened and the ladle

transferred to the BOF shop.

Keywords: HMDS, BOF, hot metal, slag

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TABLE OF CONTENTS

Sl no. Topic Page No.

Plan of Action 6

2. Customer Need 7

3. Problem Definition 7

4. Learning Aspects 8

5. Process 8-9

6. Data Collection 10-11

7. Tilting car Problems 11-13

8. Problem Root Causes 14-22

9. Ansys Analysis 22-25

10. Load Calculation 26-28

11. Progress So Far 29

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12. Problems Identified 29

13. Flow Diagrams 30-31

14. Problems Identified 32

15. Solutions Suggested 32

16. Bill Of Materials 33-35

17. Operating Values 36

18. Cylinder Calculation 36-38

19. Changes Made 39-52

20. Comparison Of Breakdown Minute 53

21. Increase In Availability 54

22. Economics Of Maintenance 55

23. Cost Analysis 56

24. References 58

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PLAN OF ACTION

7th Sem

• Problem Identification

• Data Collection

• Problem Analysis

• 2D drawing review

• Search for solution

8th Sem

• Detail solution to each problem

• Implementation of solution

• Check for effectiveness

• Possible alternate solution

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CUSTOMER NEED/ CLIENT NEED

• At JSW Steel Limited the charging time of hot metal to the basic oxygen furnace has

reduced drastically over the span of time.

• The client needs to identify the reason causing the delay in the supply time and suggest

proper rectification.

• Delay in charging time is directly linked to the production rate.

PROBLEM DEFINITION

• The charging of desulphurised metal from HMDS to converter at BOF is slow.

• As a result of which the downtime is more and converter at BOF is idle for a long period

of time.

• The direct impact is in production cost and it`s productivity.

• All the electrical equipment's are at run for a longer time decreasing the overall

efficiency.

SPECIFICATIONS/LEARNING ASPECTS

In our project we would be basically involved with the following parameters of the plant:-

• Process flow

• Hydraulic equipment’s involved

• Production downtime

• Cost Benefit

• Productivity

PROCESS

The hot metal ladle is placed into a treatment chamber. The treatment chamber is closed by a

cover or a hood, dedusting is activated and the injection lance or the impeller is lowered down

to the final treatment position. After having injected or stirred in the required amount of

desulphurisation agents, the lance or the impeller is retracted and the desulphurisation step is

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finished. Afterwards the top slag is removed by a slag skimmer. The treatment

chamber is opened and the ladle transferred to the BOF shop.

Hot metal desulphurisation (HMD) is effected by a powder deep injection system

with refractory lined immersion lance(s). The unit consists of one or more

treatment chambers with movable covers, connected to a dedusting system. A

slag skimming device including a ladle tilting frame can be integrated or provided

in a separate position.

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The desulphurised metal is carried from HMDS unit to the BOF converter by means

of overhead cranes and rails. This desulphurised metal on reaching the vertical spot

above the converter is tilted so that it`s poured into the converter for steel making.

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DATA COLLECTION

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TRANSFER CAR PROBLEMS

TILTING CARS 15%

SRM 25%

H1S1 8%H1S2

7%H2S1 1%

H2S2 4%

H3P1 2%

H3P2 5%

H4P1 9%

HOODS 15%

UNLOADING STATION

9%

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Drive bogie shaft cut

14%

Hose leakage puncture leakage

7%

Tilting problems

38%Hyd Coupling

damage12%

Cylinder damage

29%

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15

HYDRAULIC TANK CONTAMINATIONS

• In the above figure shown, there are no filters. So this is the reason why the

hydraulic tank is getting contaminated.

• 8 microns of dust flows. Hence there is no smooth flow of oil.

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INTERNAL LEAKAGE LINE OPENINGS PROVIDED BY THE SUPPLIER WITHOUT ANY

PROPER SEALING

• In the above figure, the oil filter is not sealed properly, and hence the dust is

getting settled in the oil filter.

• Due to damaged oil filter there is no smooth flow of oil and dust gets enter

in the filter.

Damaged Oil Filter

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RETURN LINE FILTERS AND SUCTION LINE FILTERS ARE MISSING

There are no filters provided in the above case and oil does not enters

back to the hydraulic tank.

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DRIVE BOGIE SHAFT CUT

Transfer cars hitting to the rail stoppers because of no limit switches

and brakes to stop the car.

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CYLINDER DAMAGE

Under discussion with the suppliers to reduce the stroke of the hydraulic

cylinder.

Cylinder bottom hose fittings modifications to avoid the hose damages.

Cylinder trunions modifications.

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ROOT CAUSE:

Tank, pump and motor are mounted on a single structure. Existing clearance

is 235mm. A small jam may disturb the allignment. This leads to the

breakdown.

Now we are modifying the hydraulic systems supporting flames. So that we

will get 600mm bottom clearance.

HYDRAULIC MOTOR COUPLING DAMAGE

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TILTING CARS BEAMS CRACKS

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CRACKS OBSERVED IN FRAME INDICATED ON BEAMS

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HOOD DAMAGING

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ANSYS ANALYSIS OF BEAMS

Max deflection : 1.321mm

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Max Shear force : 146.193 KN

Min Shear force : -108.67 KN

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Max Bending Moment: 214.833 KN-m

Min Bending Moment: 0.146E-10 KN-m

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WHEEL LOAD CALCULATION 280t

Technical parameter of the car

• Load capacity – 280t

• Dead weight – 69t

• Speed – 3-30m/min

• Wheel diameter – 1100mm

• Bearing axle hole diameter – 180mm

• Quantity of wheels – 4 Nos.

Wheel Load Calculation:

• Material – C55Mn75

• Diameter – 1100mm

Wheel tread fatigue load:

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Pr = (2Pmax*1.10+Pmin*1.10)/3

= (2*1266.0*1.10+422.50*1.10)/3=1083.3KN

Pmax – max. wheel load (with filled ladle during tilting)

Pmin – min. wheel load (empty ladle)

1.10 – impact coefficient

Wheel tread fatigue strength calculation:

K1 DLC1C2>=Pr

Where,

K1 is a constant relevant to the material

D is a wheel diameter

L is the effective contact length of wheel and railway, contact length of wheel and

railway is about 110mm

C1 is the speed factor

C2 is work class factor

So we have ,

K1DLC1C2=7.2*1100*110*1.13*1=984456N=984.5KN<Pr=1083.3KN

Result of calculation:

The 1100mm material C55Mn75 forged wheels cannot meet the requirement of the

wheel load.

Suppose wheel diameter – 1200mm

k1DLc1c2=7.2*1200*110*1.13*1=1073952N=1073.95KN<Pr=1083.3KN

Wheel diameter 1200mm also cannot meet the requirement of the wheel load.

So the tilting transfer car must be designed with 8 wheels.

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Progress so Far

• New cylinder calculations with reduced stroke length and maintaining the

basic required parameters have been done. Cylinder specs and operating

conditions have been approved for manufacturing by Danieli Corus.

• Cost for transfer car modification was approved and implementation of

design changes has started.

• Changes in Filter design has already been implemented.

Problem Identification

• Silos placed at Steel Melt Shop wasn`t delivering required set point ratio of

Magnesium and Calcium Carbide.

• The set point ratio was 1:5 but the achievable ratio was 1:10.

• This led to a lot of wastage of Magnesium resources.

• 1 tonn of Magnesium costs 2 lakh rupees.

• Improper ratio led to two problems:

1. Process time of the complete process increased drastically for each cycle of

treatment.

2. Improper desulphurization process.

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Flow Diagrams

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FLOW DIAGRAMS

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Problems Identified

• Several problems were identified after going through the complete process

in detail. Few of them are:

1. Heavy vibration during raking.

2. Faulty reading by Load cell installed for weight calculation.

3. Improper Plant Layout.

4. Raking at only one side .

5. Also, the slag accumulated led to increased local temperature and damage to

load cells and other critical components.

Solution Suggested

• Improvements suggested are:

1. Rubber padding to be used surrounding the load cell to reduce the vibration .

2. Turn buckle to be applied to every dispenser/silo.

3. Flow in pipe was severely affected because of sharp T- shaped pipes. So

smooth bends have to be provided to allow unrestricted flow.

4. Also, use of purging was suggested to immediately unblock the obstruction

caused in the pipelines emerging from silos.

5. Pressure of N2 should be increased for Magnesium silo so that proper ratio

is maintained.

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BILL OF MATERIALS

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BILL OF MATERIALS

N105

2"QC01-1501

4"QC01-1502

PSE 1504 (Set @ -18mm WC & 5.2 kPa) Vacuum/Pressure relief valve

6" KN01-1501 Knife gate valve

2" : 1-1/2" Reducer

2" : 1" Reducer

1-1/2" : 3/4" Reducer

1-1/2" : 3/4" Reducer

1-1/2" : 3/4" Reducer

1-1/2" : 3/4" Reducer

3/4" : 1/2" Reducer

3/4" : 1/2" Reducer

3/4" : 1/2" Reducer

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BILL OF MATERIALS

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OPERATING VALUES

• Magnesium total mass flow: 62 Kg

• Calcium Carbide total mass flow : 504 Kg

• Mass flow rate of Magnesium: 7.6 kg/min

• Mass flow rate of Calcium Carbide: 53.3kg/min

• Calcium Carbide pre injection: 40 Kg

• Magnesium injection pressure: 324.7 Kpa

• Calcium Carbide injection pressure: 464.4 Kpa

• Nitrogen flow pressure: 983 Kpa

• Nitrogen gas temp: 320 c

• Duration of Magnesium flow: 8:4 min

• Duration of calcium carbide flow: 9:27 min

CYLINDER CALCULATIONS

Given:

Bore dia r = 280mm

Rod dia R = 140mm

Length l = 81.1023inch

Stroke = 43.3inch

Working Pressure P = 100bar

Formulas:

• Cylinder Blind End Area = pi*r2 = 3.14*(140)2

=95.48 inch2

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• Cylinder Rod End Area = Cylinder Blind End Area -(pi*R2) = 61602.8- (pi*

702 ) = 71.6134 inch2

• Cylinder Output force (In pounds):

For Push: Pressure*Cylinder Blind End Area

= 100*14.508*95.48 = 138446 pounds

For pull: Pressure*Cylinder Rod End Area

= 100*14.508*71.6134 = 103839.43 pounds

• Fluid pressure in PSI to lift load (in PSI) :

For push: Pounds of force needed/Cylinder area

= 138446/95.48 = 1450 PSI

For pull : 138446/71.61 = 1933.33 PSI

• GPM Of Flow Required For Cycle Speed:

(Cylinder Area x Stroke Length in Inches) ÷ (231 x 60) ÷ (Time in

seconds for one stroke)

= (95.48*43.3)/(231*60)/10= 3.5 GPM ( for extension)

= (71.61*43.3)/(231*60)/10= 2.51 GPM ( for retraction)

• Cylinder Speed (inch/sec):

(231*GPM)/(60*net cylinder area)

= (231*3.5)/ (60*95.48) =0.35 inch/sec ( for extension)

= (231*3.5)/ (60*71.61) =0.47 inch/sec ( for retraction)

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SNAPS

39

Changes Done:

1.Increase of ground clearence for rail cars:

Before- 235mm ground clearence

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After- 600mm ground clearence

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2. Beam cracking improvement

Before-

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After- Ribs of 20mm were welded to make the structure strong.

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3. Slag Raking machine: Turning of slag raking machine about its axis used to

cause damage as it used to collide with the rail car below

Before: (Straight Frame)

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After: ( Zig-Zag Frame)

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4.Hydraulic Tank Modification: Internal leakage port without any proper sealing

lead to hydraulic fluid contamination.

Before:

46

After: ( New sealed port provided)

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5.Modification of Cylinder Piston: 1498mm of stroke length used to bend the

piston rod because of excessive load.

Before-

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After- Piston stroke was reduced to 1390 mm without reducing the bore. The

reduction in piston stroke also increased the ground clearence as seen.

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6.Return line filters added: Earlier there was no filters provided on return line

because of which the dirt of piston used to flow into the hydraulic tank and thereby

contaminating the hydraulic fluid.

Before-

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After: A new filter fitted into the return line.

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7.Hood jamming: Because of larger thickness of the lance hood, slag of the hood

and slag of laddle used to hit each other and cause structural damage.

Before:

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After: ( thickness is reduced by 3mm)

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Comparison of Breakdown minutes

0

200

400

600

800

1000

1200

1400

1600

Dec Jan Feb March April

Before 1300 1400 1350 1230 1500

Post Car repair 0 463 550 432 440

Post completion 0 0 200 130 120

Bre

akd

ow

n M

inu

tes

Months

Pre Implementation VS Post Implementation

Before Post Car repair Post completion

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Increase in availability

Probability of equipment availability = Up time/ (up time+down

time)

Probability ( before) :

Up time= 4260 mins for 4 stations

Down time= 1500 mins

So, probability of availability = 4260/ (4260+1500)

= 0.73

Probability ( after):

Up time=4260 mins

Down time= 200mins

So, Probability of availability= 4260/ (4260+200)

= 0.95

Therefore, it is evident that after the structural changes were brought in

the equipment availabilty increased from 73% to 95%. This ensured

continous and smooth production process.

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Economics of Maintainance

Breakdown time/month= 1555.2 mins

Breakdown maintainance cost= Rs.75/min

Total cost=Rs. 1,16,640

Preventive maintainance cost=Rs. 20,00,000

Breakdown time/month post preventive maintainance= 288 mins

Total cost incurred for breakdown maintainance= Rs.21,600

So, the question now is was the preventive maintainance done economical?

Number of months required to recover the cost incurred for preventive

maintainance:

Cost of maintainance /month= 116640+21600 = Rs. 1,38,240

Months required to sum to preventive maintainance cost= 2000000/138240

= 14.46 months

So, the cost will be recovered in just 1year 3months. This project can thus be

considered to be very economical.

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Cost Analysis

The next important factor after time is the cost factor. Will this project be

able to save company funds?

A simple analysis based on previous obtained results will show the

following:

Previous monthly maintainance cost: Rs. 1,16,640

Current monthly maintainance cost: Rs. 21,600

% savings: (116640-21600)/ 116640 = 81.48%

Initial67%

1st Phase21%

Final Phase12%

Maintainance cost

Initial 1st Phase Final Phase

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Timeline of our project

Start Date- 8th September 2013

End Date- 25th April 2014

PROJECT START

PROBLEM STATEMENT

INVESTIGATION

COLLECTION OF DATA

BRAIN STORMING

ALTERNATIVE IDEAS

DESIGNING

APRROVAL

IMPLEMENTATION

TESTING AND MODIFICATION

PROJECT END

8 Sep 8 Oct 8 Nov 8 Dec 8 Jan 8 Feb 8 Mar 8 Apr

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References

www.jsw.in

www.sws-demag.com

www.google.com

Strength of Materials by Bhavikatti

Ansys tutorials

JSW supplier data

JSW technical library