“Preparation of general arrangements engineering drawings of energy efficient typical 15 tph top

fired pusher hearth re-heating furnace with coal based producer gas firing”

for the project

“Upscaling energy efficient production in small scale steel industry in India”

Submitted to:

United Nations Development Programme

55, Lodhi Estate, New Delhi 110003

Submitted by:

M/s R.K. Industrial Enterprises, Faridabad

Submission on:

29th April, 2014

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ABBREVIATIONS:

mm millimeter tph tonne per hour kg/h kilogram per hour hp horse power kW kilo watt l litre l/h litre per hour NB Nominal bore mmWC millimeter of water column Rs Indian rupee CFM cubic feet per minute

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CONTENTS

EXECUTIVE SUMMARY………………………………………………………………………………………………3

1. INTRODUCTION……………………………………………………………………………………………..…...5

2. FURNACE DESIGN PARAMETERS……………………………………………………………..………….5

3. ENERGY EFFICIENT MEASURES IN THE RE-HEATING FURNACE…………..………………9

4. COST OF THE FURNACE………………………………………………………………………………..……..9

5. BENEFITS W.R.T. PERFORMANCE AND PAY-BACK…………………………………………..…11

6. GENERAL ARRANGEMENT DRAWING: LAYOUT & AUXILIARY…………………...……….12

7. GENERAL ARRANGEMENT DRAWING: STRUCTURAL……………….…………………………13

8. GENERAL ARRANGEMENT DRAWING: PIPING NETWORK…………………………………..14

9. GENERAL ARRANGEMENT DRAWING: REFRACTORY LINING……………………………...15

10. SINGLE LINE DIAGRAM……………………………………………………………………………………...16

11. GENERAL ARRANGEMENT DRAWING: RECUPERATOR………………………………………17

12. GENERAL ARRANGEMENT DRAWING: CHIMNEY…………………………………………….....18

LIST OF TABLES

Table 1 : Design data of the furnace ........................................................................................................ 5

Table 2 : Dimensions of the furnace ....................................................................................................... 6

Table 3 : Details of combustion system of the furnace .................................................................... 7

Table 4 : Cost breakup for furnace .......................................................................................................... 9

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EXECUTIVE SUMMARY

UNDP in association with Australian Aid Programme & Ministry of Steel, Government of

India is implementing a project titled “Upscaling energy efficient production in small

scale steel industry in India”. The objective of this project, which was launched in July

2013, is to scale-up adoption of energy efficient technologies in small scale steel

industry in India. In line with project’s continuous endeavor to provide inputs on energy

conservation, a typical design of re-heating furnace, based on pulverized coal as fuel,

was developed.

Re-heating furnace was designed based on most commonly prevailing operational

practices in small scale steel industry in India. The basic design has been carried out

considering “state of the art” technology and accessories. The capacity for design was

considered as 15 tph as it was the mean average of varying capacity of re-heating

furnaces in small scale steel industry in India and to provide inputs to larger section of

the sector on ideal scenario. The overall designing and development of general

arrangement drawings were done by aiming the best possible specific coal consumption

of 70 to 120 kg/t for producer gas based furnace. Further consideration on design of

various systems of re-heating furnace is depicted in below table.

Parameter Design consideration

Billet dimension & temperature

gradient

100x100x1,500 mm &

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As compared to conventional producer gas fired furnace, this energy efficient furnace

would ensure saving of atleast 20 to 30 kg/t in specific coal consumption. And such

saving is projected by incorporating various energy conservation measures in re-

heating furnace viz. installation of PID controller system for air fuel control ratio in

soaking zone and heating zone-1 & 2, waste heating recovery system, optimum

refractory & insulation etc. Overall investment for installing energy efficient furnace is

arrived at by considering prevailing market rates for various equipment, structural steel

& civil works. It is estimated that the investment for re-heating furnace can be

recovered in 2 ½ years and such calculation is done by considering difference in specific

fuel consumption of conventional furnace & energy efficient furnace.

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1. INTRODUCTION

UNDP in association with Australian Aid Programme & Ministry of Steel,

Government of India is implementing a project titled “Upscaling energy efficient

production in small scale steel industry in India”. The objective of this project, which

was launched in July 2013, is to scale-up adoption of energy efficient technologies in

small scale steel industry in India.

There is a massive scope of energy saving in existing and new upcoming units.

The project seeks to facilitate the dissemination of energy efficient technologies in the

Steel Re-rolling Mill (SRRM) sector to improve productivity and cost competitiveness,

and reduction of Greenhouse Gas (GHG) emissions. The re-heating furnace forms the

key area for energy efficiency intervention in a typical SRRM unit, due to high energy

(thermal energy) consumption.

Considering a large potential for energy conservation in the SRRM sector, the

core objectives of this project is to create an access for adopting energy efficient

technologies for the SRRM units.

In view of the above, general arrangement drawings (with dimensions) for

typical 15 tph energy efficient furnace with producer gas as fuel has been prepared.

2. FURNACE DESIGN PARAMETERS 2.1 Design criteria:

A capacity of 15 tph has been considered for designing the furnace. Nominal

capacity of the furnace is related to (i) Size of the billets, (ii) Discharge temperature, (iii)

Permitted temperature gradient across the billet height, (iv) Grade of material (thermal

conductivity) and (v) Heating regime. Therefore, the furnace has been designed taking

into consideration, certain typical operational practices prevailing in the SRRM sector.

The basic design data considered are as below:

Table 1 : Design data of the furnace

Sl.

No.

Parameter Unit Dimension

a. Design capacity of the

furnace

tph 15

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Sl.

No.

Parameter Unit Dimension

b. Biller cross-section mm X mm

X mm

100X100X1,500

c. Material - MS Grades

d. Discharge temperature OC 1150.

e. Permissible temperature

gradient from top to

bottom

OC < 50

f. Fuel - Coal based producer gas with the

following composition by weight

(%):

CO=23-28; H2=7-10; CH4=1-2; CO2=

4-5; O2=0.2-0.8; N2=45-50;

2.2 Discharge capacity of the furnace:

Depending up on the variations of the input parameters, the discharge capacity

can be higher or lower than the specified 15 tph. Productivity of the furnace also

depends upon the temperature profiles maintained by the operator in the respective

zones. The furnace can also be used for heating of alloy steels but the production

capacity of the furnace will reduce due to change in the grade of the input material.

2.3 Broad dimensions of the furnace:

The broad dimensions of the furnace are given below:

Table 2 : Dimensions of the furnace

Sl. No. Parameter Unit Dimension

1. Overall length of the furnace m 22.00

2. Effective length of the furnace m 18.90

3. Length of the soaking zone m 5.0

4. Length of the heating zone m 6.5

5. Length of the pre-heating zone m 7.4

6. Overall width of the furnace m 4.732

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Sl. No. Parameter Unit Dimension

7. Inside width of the furnace m 3.5

8. Height of the roof above the hearth

At soaking & heating zones

At pre-heating zones (Unfired zone)

mm

1500

600 2.4 Type of roof: Flat roof with hanger bricks 2.5 Combustion system:

The combustion system is divided into three zones viz. Soaking Zone, Heating

Zone and Pre-heating Zone. Details are below:

Table 3 : Details of combustion system of the furnace

1. Total heat load as per the heat balance: 6500 nm3/h.

2. No. of burners: Soaking zone: 3 (size: 5A ), Heating zone: 6 (size: 4A ) Make :

Continental.

3. Location of the burners:

Soaking zone: On the discharge end wall.

Heating zones: On the side walls; 3 burners on each side with staggering

arrangement.

4. Combustion air supply: Combustion air will be supplied by a centrifugal fan of

below specifications:

Capacity of the fan: 5400 CFM

Discharge pressure: 900 mmWC

Motor capacity: 75 kW

5. Pipelines: Pipelines for supply of combustion air are designed with sufficient

reserve capacity so that pressure drop will meet the blower discharge capacity.

The dimensions for various pipelines are as follows:

Air pipeline (main header): 450 NB, Air pipeline (branch pipes for burners): 1.

Soaking Zone: 300 NB, 2. Heating Zone: 250 NB.

Gas pipeline (main header): 800 NB, Gas Pipeline (branch pipes for burners):

600 NB.

6. Flue system: Exhaust system for evacuating flue gases is designed taking into

account the resistance of the flue path, as envisaged in the general layout.

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Flue port is taken from the side and the flue line will be underground. For 15 tph

furnace, the dimensions of flue duct is: 1,000 mm.

The chimney has been designed considering pollution control norms. The broad

dimensions of the chimney are as follows: height : 30,000 mm; diameter: 900

mm.

7. Waste heat recovery: Waste heat recovery is done through a tubular cross flow

type two pass metallic u-tube type recuperator with a capacity for preheating air

to a temperature of 300 to 3500C. The recuperator will be located in

underground flue line. Detailed specifications are provided in the recuperator

drawing.

8. Refractory & insulation: Refractory & insulations forms a major role in

minimizing heat losses from the side walls and roof. An optimum refractory &

insulation pattern has been suggested to minimize the heat loss due to radiation.

Soaking & heating zones: For the soaking and heating zone sidewalls, a

refractory lining should consisting of 230 mm thick H.D. firebricks (60%

Alumina) followed by 115 mm thick light weight firebricks (hot face insulation)

backed by 115 mm thick Mica insulation bricks (cold face insulation) backed by

75 mm thick calcium Silicate block insulation.

Preheating zone: For the pre-heating zone, it is suggested to go for 230 mm

thick H.D. firebricks (60% Alumina) backed by 115 mm thick light weight

firebricks (hot face insulation) backed by 115 mm thick mica insulation bricks

(cold face insulation) backed by 75 mm thick calcium Silicate block insulation

has been considered.

Roof:- For the re-heating furnace roof, high alumina firebricks 60% Al2O3, 340

mm for anchored bricks and 225 mm for unanchored bricks partly backed by 65

mm thick ceramic fiber blanket (128 kg/m³), 50 mm thick insulation castable

and 50 mm thick calcium silicate block insulation has been considered.

10. Control system: The furnace has been provided with controls for the following.

1. Temperature monitoring for all the three zones

2. Air to fuel ratio control.

3. Furnace pressure control

The furnace has been designed with three control zones. All the three zones will

be with controls for temperature and air to fuel ratio.

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3. ENERGY EFFICIENT MEASURES IN THE RE-HEATING FURNACE

Furnace design is based on the calculations. Some of the energy efficient

measures incorporated in the design are:

Furnace length has been determined by heat transfer calculations. The furnace

length is calculated considering the preheated air up to the temperature of 3500C

The locations of the burners are suggested for proper heat transfer and

maximum efficiency.

Low thermal mass and low conductivity ceramic fiber is used as back up

insulation for walls and total roof insulation in the preheating zone to minimize

heat losses through walls and roof.

Furnace pressure control has been suggested to avoid the air ingress in the

furnace as it reduces the temperature of furnace and increases scale loss.

Chimney is design as per the pollution control norms and for effective flow of

flue gases.

Refractories and insulation suggested in order minimizing the radiation heat loss

from the side walls and roof.

High efficiency U-tube type cross-flow metallic recuperator has been suggested

to maximize the combustion pre-heat temperature to reduce fuel consumption.

4. COST OF THE FURNACE

The Total cost of 15 tph energy efficient re-heating furnace will be approx. Rs

1.15 crore and breakup is as below:

Table 4 : Cost breakup for furnace

Sl. No.

Description Qty. Rate Amount

1 Fabricated steel structure total weight

23,000 kg

70.00 per kg 16,10,000.00

2 H.R. casting total weight 16750 kg

58.00 per kg 9,71,500.00

3 Combustion air pipe line One lot 2,85,000.00 each

2,85,000.00

4 Gas pipe line from the gas plant to furnace burner side with complete accessories

One lot

12,30,000.00 each

12,30,000.00

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Sl. No.

Description Qty. Rate Amount

5 Blower 75 hp x 36” WGP with motor

01 no. 2,20,000.00 each

2,20,000.00

6 Recuperator model 70 FS One 65,0000.00 each 65,0000.00 7 Ejector with gear box 15 hp

motor One 5,25,000.00

each 5,25,000.00

8 Hydraulic pusher with suitable power pack

One 7,50,000.00 each

7,50,000.00

9 Chimney 900 mm 30 meter length

One 6,25,000.00 each

6,25,000.00

10 Door and damper plate lifting manually up down movement arrangement like wire rope, pulley, winch, nut bolt etc.

One lot 65,000.00 each

65,000.00

REFRACTORY MATERIAL 11 Insulation brick std 230 x 115 x

76 (cold face) 19,800

nos. 16.50 each 3,26,700.00

12 Insulation brick std 230 x 115 x 76 (Hot face)

4,000 nos.

55.00 each 2,20,000.00

13 Fire bricks IS-6 std 230 x 115 x 76

18,150 nos.

24.00 each 4,35,600.00

14 Fire bricks std IS-8 230 x 115 x 76

5,500 nos.

28.00 each 1,54,000.00

15 Fire bricks std Al203 60% 230 x 115 x 76

6,600 nos.

75.00 each 4,95,000.00

16 Fire bricks end arch Al203 60% 230 x 115 x 76 x 63

660 nos. 28.00 each 18,480.00

17 Fire bricks side arch IS6 230 x 115 x 76 x 63

1,500 nos.

24.00 each 36,000.00

18 Skew block IS-8 4.5” X 4.5” X 4.5” 355 nos. 200.00 each 71,000.00 19 Skew block 9” x 9” x 9” AL203

60% 88 nos. 275.00 each 24,200.00

20 Hanger bricks Al203 60% 1,350 nos.

390.00 each 5,26,500.00

21 Shoulder bricks Al203 60% 1,170

nos.

380.00 each 4,44,600.00 22 Accoset 50 (fire cement) 120 bags 675.00 each 81,000.00 23 Castable refractory super 30 bags 1,075.00 each 32,250.00 24 Fire clay 50 kg packing 100 bags 250.00 each 25,000.00 25 White heat ‘K’ 20 bags 1,475.00 each 29,500.00 26 Ceramic fiber blanket 64 RT 55 rolls 1,000.00 each 55,000.00 27 Hysil block 900x600x50 TH 170

sheets 950.00 each 1,61,500.00

28 Chrome magnesite bricks Std 1045 nos.

250.00 each 2,61,250.00

29 S.S. 304 stud with washer 8” long

100 nos. 95.00 each 9,500.00

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Sl. No.

Description Qty. Rate Amount

30 C.I. casting hangar with rod 1,350 sets

250.00 each 3,37,500.00

Total material value 1,06,76,080.00 31 Furnace structure fabrication, refractory lining , erection &

commissioning labor charges with installation of all equipments and erection of chimney etc.

8,50,000.00

Total 1,15,26,080.00

Note: The above table gives only a rough estimate. The actual cost will vary as

per detailed engineering.

5. BENEFITS W.R.T. PERFORMANCE AND PAY-BACK

On successful operations the furnace will be rated to produce within ±10% of its

rated capacity.

The hearth life will be more than 1½ years and the roof life will be more than 2½

years.

Scale losses shall be less than 1.0%.

Compared to typical furnace, the saving potential envisaged for the energy

efficient furnace is approximately in the range 15-20%.

Uniform temperature of the input material will also reduce the crop losses and

yield will also improve.

Pay back for newly designed furnace would be around 2 to 2 ½ years.

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UHRGUD A@MCGT L@GDMCQ@ 'BNMRTKS@MS(

UNDP15 TPH REHEATING FURNACEWITH FURNACE OIL FIRING

GENERAL ARRANGEMENT: RECUPERATOR

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