k m tandon and ashwani kaul

Efficiency improvement and cost optimization in

Fertiliser Plant- Case Study

K M Tandon and Ashwani Kaul

1

FAI Programme on Business Intelligence, Forecasts and Planning for

the Fertiliser Sector – 27th Feb. – 1st March, 2012

Efficiency Improvement and Cost Optimization in Fertiliser Plant- A Case Study

Shriram Fertilisers & Chemicals : Kota( A Unit of DCM Shriram Consolidated Ltd.)

FAI Programme: 28th Feb, 2012

2

� Introduction

� Need for efficiency improvement and cost optimization

� Approach adopted at SFC Kota

� Modifications / up-gradations implemented

� Feedstock changeover to Natural Gas

� Conclusion

Contents




2



3

Introduction

Shriram Fertilisers & Chemicals

Shriram Vinyl Chemicals

Shriram Cement Works

Fenesta Building Systems

Shriram Polytech

Kota Complex




3



5

475 km from Delhi on the main western broad gauge line line from Delhi to Mumbai

235 km from Jaipur on the NH 12From Jaipur to Jabalpur

Location

Manufacturing Facilities

PLANTS / PRODUCTS UNIT CURRENT PRODUCTION LEVELS

Power MW 133

Fertiliser - Ammonia

- Urea

TPD

,,

700

1200

Chlor Alkali - Caustic Soda

- Chlorine Liquefaction

- HCl

- SBP

TPD

,,

,,

,,

325

180

175

35

Plastics - Calcium Carbide

- PVC Resin

TPD

,,

340

200

Cement TPD 1200

Shriram Polytech - PVC Compounds TPD 60

Fenesta - Window and Door profiles TPA 3000




4



Fertiliser Plant

Details

Commissioned in 1969 with capacity of 450 TPD Ammonia / 700 TPD Urea

Expanded in 1974 to 600 TPD Ammonia / 1000 TPD Urea

Present operation level is 700 TPD Ammonia / 1200 TPD Urea

� Ammonia Plant based on Haldor Topsoe’s steam reforming process

� Urea plant based on Stamicarbon’s total recycle process with crystallization route for urea finishing

� Ammonia plant modified to use Natural gas in 2006

� Plant running fully on NG since May,2009




5



9

Need for

Efficiency Improvement

and Cost Optimization

Bath - tub curve approach to plant lifecycle

Need

No. of Years in operation

No

. o

f B

reakd

ow

ns

Initial Defects

Wear & tear

5 10 15 20




6



11No. of Years in operation

No

. o

f B

reakd

ow

ns

5 10 15 20 25 30 35

Challenge is to negate the impact of efficiency loss

and equipment wear due to aging

Need

12

Approach adopted

at SFC Kota




7



13

� Increasing capacity utilization

� Re-look into original design of equipment

Approach adopted at SFC KotaApproach adopted at SFC Kota

� Steam conservation

� Water conservation

� Benfield system chemicals

� Feedstock conservation and substitution

14

• Identification of process bottlenecks

� Increasing capacity utilization

• Incorporation of available retrofits

• Systematic equipment replacement plan

• Reduction in shutdown frequency and duration

� Re-looking into original design of equipment

• Modifications in equipment

• Redesign of boilers and exchangers

• Simplification of piping and replacement to decrease ∆P

• Change of packings

Approach adopted at SFC Kota




8



15

� Feedstock conservation and substitution

• Heat recovery from flue gases from furnaces

• Packing gas recovery


• Better leakage class of vent valves

• Use of steam for heating instead of Naphtha / Natural Gas

� Steam conservation

• Use of steam at right temperature

• Steam Trap management

• Online leak sealing

• Reuse and recycle of water

• Cooling water treatment

� Water conservation

� Benfield system chemicals

• Re-oxidation cooler for V2O5

• Better house keeping and maintenance practices.





9



� Cost optimization

• Import substitution

• Local vendor development

• In house NDT

• Vibration monitoring

• Reclamation and reuse of old parts

• Replacements on condition monitoring results

� Reclamation of Lubricating Oil

� Use of Aspen for process analysis and design


18

� Reforming Section

Modifications / upgradations

• Reformer catalyst tubes MOC changed from original HK 40 to Manuarite in 2000. With this ID of tubes increased from 115 mm to 131.6 mm

• A water spray tower was installed in 1980 at the downstream of the waste heat boilers to maintain HTS inlet temperature by adding BFW

• The primary reformer induced draft fan was also replaced with a higher capacity one so that proper excess air of 2.5% O2 could be maintained

• In order to reduce the heat duty of fired preheater upstream of primary reformer, a steam fired heater was installed

• A convection section was added in direct fired preheaters to utilise waste heat from flue gases

• Additional heat recovery from the Reformer convection zone by addition of extra rows of tubes in air and steam coils




10



19

� Carbon dioxide removal and beyond

• 25 mm Metallic (SS) Pall rings were installed in the top two beds and 38 mm rings were installed in the bottom two beds in place of ceramic rings

• In order to reduce gas velocities at the CO2 Absorber outlet an additional Separator was installed in 1979 itself . This helped in avoiding liquid carryover to the Methanator

• To reduce the temperature of the bottom to top potassium carbonate solution a larger size HPC cooler had to be installed in 1983

• The synthesis gas compressors which are motor driven reciprocating machines posed a bottleneck in achieving full plant loads. The cylinder bores of 1st stage were increased from 289 to 305 mm as there was some margin in the motor. This enabled a capacity increase of 9 %


20

� Installation of a radial Ammonia Converter basket

• The original TVA Type Axial Flow Ammonia Converter Basket was due for replacement in 1992

• A radial flow converter was installed as replacement of old axial flow basket

• This has made the running of smaller 120 TPD Ammonia Synthesis loop unnecessary

• Since the loop did not have any waste heat boiler, the energy was being wasted to the cooling tower. This could be avoided with the installation of the radial converter





11



21

� Period between turnarounds

• Earlier the plant turnarounds were taken on annual basis. However, the IBR later allowed operation of waste heat boilers upto two years.

• With judicious planning of the overhauling of the reciprocating compressors the turnaround are now taken up once in two years.

• This has improved availability of plant


22

Feed stock conversion

from

Naphtha to Natural Gas




12



23

� Why change to Natural gas

• Energy cost constitutes about 80% of total cost of production of urea

• After removal of APM from naphtha, its prices touched a very high value of Rs. 55,000/MT

• Gas is a clean fuel as compared to naphtha

• Gas is cheaper as compared to naphtha

• Reduced cost of production leads to improved competitiveness

• Favourable government policy for feedstock changeover

� Reduced subsidy outgo

Conversion to Natural Gas

24

• Replacement of all 252 burners from self aspirating naphtha fired burners to forced draft Natural gas / Naphtha fired burners

• Installation of a Combustion Air preheater

• Installation of a new feed Natural Gas preheater

• Installation of new FD Fan and ID Fan at ground floor

• Installation of fuel NG preheaters

• Replacement of Steam Naphtha Coil and inlet distribution headers for steam naphtha mixture going to the catalyst tubes

• Removal of BFW Coil from convections section of primary reformer furtnace


� Modifications done




13



25

� Control system upgradation

• 35 year old pneumatic controls required frequent maintenance and were facing obsolescence

• More accurate control helps in better optimization of plant parameters

• Temperature scanner was also error prone and inaccurate

• Plant interlocks were relay based

• Pneumatic controls replaced by latest Digital Control System

• This has enabled

� Centralised Operation Monitoring� Process behaviour analysis� Monitoring of Alarm management

� Process history storage


26

� DCS Chosen is Emerson’s Delta – V system

� Plant safety interlocks have been implemented in integrated Delta - V SIS which is TUV approved system for SIL3 applications.

� Salient features are

� 1100 Nos I/O’s

� Ease of operation

� Trends , process history, alarms available.

� Built on commercially available personal computers as work

station and engineering stations.

� Windows platform

� Proven ethernet communication technology

� Scalable to add more controllers and operating stations as

required





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27

� SIL 3 safety system

� Latest Foundation field bus technology foundation field bus has been used for temperature signals and few pressure and flow monitoring requirements.

� Asset management system

� Delta –V AMS suite has been installed for centralised configuration , diagnostics, maintenance and history record for HART and FF field devices.

� Operator interface

� 5 Operating stations with 19” LCD monitors in a control room

� Screens interchangeable in all respects

� Operator can scroll through the entire plant seamlessly.


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Conclusion




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29

Old pneumatic controls replaced by state of the art Digital control System in 2006

Systematic effort to optimise the operation the energy consumption has been reduced significantly

7.3 2 5

7.4 4 7

7.7147.779

7.8 57.8 87.8 5

7.8 1

7.9 7

8 .0 9

8 .28 .15

8 .19

8 .4 3

8 .2 5

8 .3 5

8 .53

8 .3 8

8 .52

9 .0 2

7.3

7.5

7.7

7.9

8.1

8.3

8.5

8.7

8.9

9.1

9.3

91

-92

92

-93

93

-94

94

-95

95

-96

96

-97

97

-98

98

-99

99

-00

00

-01

01

-02

02

-03

03

-04

04

-05

05

-06

06

-07

07

-08

08

-09

09

-10

10

-11

MKCal/MT Urea

Energy performance of the plant

30

Old pneumatic controls replaced by state of the art Digital control System in 2006

Focus on reducing R & M Cost

12.24

13.85

12.312

12.33

14.84

5.25.8

4.7

7.5

5.7

10.7

7.5

10.0

8.3

11.0 10.5

12.911.5

9.7

12.9

13.1

8.0

0

2

4

6

8

10

12

14

16

18

20

88

-89

89

-90

90

-91

91

-92

92

-93

93

-94

94

-95

95

-96

96

-97

97

-98

98

-99

99

-00

00

-01

01

-02

02

-03

03

-04

04

-05

05

-06

06

-07

07

-08

08

-09

09

-10

10

-11

(P

)

Avg. inflation rate during last 7 years 5.18% per year

Growth rate R & M Cost during last 7 years 0.5% per year

R & M Cost contained to below inflation rate – Reduction in real terms

Rs.C

rs/Y

r.




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31

Maintaining Plant Health with min. Capex

1.9

1.8

2.813.72

6.158.7

8.1

9.6

2.2

8.4

4.3

18.2

6.0

34.7

6.68.0

6.74.4

1.8

30.4

1.10.92.0

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

88

-89

89

-90

90

-91

91

-92

92

-93

93

-94

94

-95

95

-96

96

-97

97

-98

98

-99

99

-00

00

-01

01

-02

02

-03

03

-04

04

-05

05

-06

06

-07

07

-08

08

-09

09

-10

10

-11

(P

)

Rs

.Crs

.

Average Capex Rs. 7.8 Cr./Year

32

� First Prize in Safety Performance FAI Annual Seminar for Safety in 2009

Recognition

� 2nd Prize in Energy Conservation in Fertilizer Sector by Bureau of Energy Efficiency ( BEE ) in 2011

� British Safety Council’s Sword of Honor for Safety Performanceat International level for four consecutive years ( 2007 – 2011)

� First Prize in Technical Article for FAI Newsletter in 2008




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The way forward - Energy savings schemes

S. No.

Scheme Expected energy savings

MKCal/MT Urea

A. AMMONIA PLANT

1 Heat Exchange Reformer (KRES) 0.32

2 Additional cell in cooling tower 0.04

3 Chiller at synthesis gas compressor suction 0.02

B UREA :

1 High Efficiency Combined (HEC) process for Urea or 1st stage heat recovery

0.16

2 Evaporation route for Urea Plant 0.073

3 Additional cell in cooling tower 0.04

4 Natural Draft prilling tower 0.02

5 DCS and N/C Metering for urea plant 0.01

Total (A+B) 0.683

34

Thank you

[email protected]

k m tandon and ashwani kaul

Documents

natural gas

fertiliser

approach adopted

efficiency

fai programme

business intelligence

case study

1st march