INDIAN FAREMRS FERTILISER COOPERATIVE LIMITED PHULPUR UNIT

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I F F C O

12/8/2011 Steam Reforming- Presented by Sanjay Katheria 502237

Outline of the Presentation

2 12/8/2011 Steam Reforming- Presented by Sanjay Katheria 502237

General Chemistry of Steam Reforming

Catalyst

Operating Conditions

Pre Reformer

Primary Reformer

Secondary Reformer

Source & References

Steam reforming of natural gas is the most common method of producing commercial bulk hydrogen as well as the hydrogen used in the industrial synthesis of ammonia.

Steam reforming can be described by the reversible reaction(s)

CnHm + nH2O nCO + (n + m/2 ) H2 CH4 + H2O CO + 3H2 [ΔH = +206 kJ mol-1] CO + H2O CO2 + H2 [ΔH = -41 kJ mol-1] CH4 + 2H2O CO2 + 4H2 [ΔH = +165 kJ mol-1]

Strongly endothermic reaction

General Chemistry Introduction

Conclusion

Steam Reformers

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Rhodium, Nickel, Palladium, Platinum and combinations of these metals.

Nickel based catalysts widely used, although nickel-based catalysts require a high reaction temperature and an excess amount of steam to prevent coke deposition on the catalyst surface.

Alumina, Zirconium dioxide and Magnesium Oxide etc. as catalysts support.

Low and high alkali catalysts

Catalysts

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Source & References

Introduction

Conclusion

Steam Reformers

Many poisons affect reforming catalysts including sulphur, metals, halides and phosphates. Sulphur is a particular problem because:

- Nickel is a very good sulphur adsorbent - Only a small amount of sulphur can cause problems , sulphur can totally deactivate a reforming catalyst

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Source & References

Introduction

Conclusion

Steam Reformers

Catalysts

Reforming: Diffusion Limited Reaction

Shape of the Catalyst - High Surface Area - Pressure drop across catalyst bed - Good uniform packing for better heat transfer/distribution

Tubular Reforming catalyst performance can chiefly be

measured by three variables: - Exit Gas Methane Leakage - Tube Metal Temperature (gradually increasing to the

equipment limitations) - Gas Pressure Drop

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Catalysts

Source & References

Introduction

Conclusion

Steam Reformers

Combination of a relatively small catalyst size in the top and a larger size in the lower part of the tubes.

Carbon formation over catalyst surface – 2 CO C + CO2 CH4 ➔ C + 2 H2 CO + H2 ➔ C + H2O

– Low S/C ratio – High C/H ratio and relative low temperature – Low temperature conditions at feed inlet (upper part of catalysts tubes).

Catalysts

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Source: HTAS Catalyst Manual Source &

References

Introduction

Conclusion

Steam Reformers

Carbon to Hydrogen (mass)ratio of feed -(C/H ratio)

Steam to Carbon (molar)ratio - (S/C ratio)

Temperature

Pressure – Higher temperatures result in less methane and more

carbon monoxide. – Surplus of steam favors both low methane and low carbon

monoxide. – High pressure increases the methane content.

Operating Conditions

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Source & References

Introduction

Conclusion

Steam Reformers

Operating Conditions

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%CH4 (dry)

%CH4 (dry)

Source: HTAS Catalyst Manual

Source & References

Introduction

Conclusion

Steam Reformers

Pre Reformer Primary Reformer Secondary Reformer

Type of furnaces: - Side fired furnace - Vertical fired multi row furnace

Comparison of Side Fired and Vertical Fired Furnace

– Mode of heat transfer – Temperature distribution – Size – Heat loss – Efficiency

Steam Reformers

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Source & References

Introduction

Conclusion

Steam Reformers

11 12/8/2011 Steam Reforming- Presented by Sanjay Katheria 502237

Adiabatic Pre Reformer

Main purpose of primary reformer to convert higher hydrocarbons in to methane.

To achieve the reaction temperature, feed is heated in mixed feed coil of convection section of primary reformer.

Two Catalyst Beds

Source & References

Introduction

Conclusion

Steam Reformers

Process Gas Inlet

Process Gas Outlet

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Reactions involved: CnH2n+2

+ 2H2O Cn -1H2n + CO2 + 3H2 - Heat CH4

+ 2H2O ➔ CO2 + 3H2 - Heat CO2 + H2 ➔ CO + H2O - Heat Net effect is slight increase in temperature (12oC) – Performance Indicator

12 Temperature Indicators: 7 in Top Bed and 5 in Lower Bed

Temperature Profile: indication of catalyst deactivation

Reactions in Pre Reformer…

Source & References

Introduction

Conclusion

Steam Reformers

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Inlet Outlet

Temperature 490oC 505 oC

Pressure 36.8 kg/cm2 35.7 kg/cm2

Composition(in % Dry basis)

CH4 0.35 50.80

H2 36.59 24.45

N2 12.20 3.02

Ar 0.15 0.04

CO - 0.54

CO2 0.46 20.15

C3 + 50.25 -

Process Gas Flow Rate(Dry) 18305 Nm3 /hr

Total Gas Flow Rate 192805 Nm3 /hr

Operating Conditions…

Source & References

Introduction

Conclusion

Steam Reformers

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Steam Reforming- Presented by Sanjay Katheria 502237

Operating Conditions

Minimum Maximum Normal

Temperature 0C 380 600 490

Pressure kg/cm2 34 46 39

Reactor Data

ID(mm) Height(mm) Volume(m3)

Bed # 1 2750 2350 13.90

Bed # 2 2750 1450 9.50

Size and Shape: 11x5 mm ( cylindrical with 7 holes)

Ni 25%

Al2O3 11%

MgO balanced

Pre Ref0rmer Catalyst

Source & References

Introduction

Conclusion

Steam Reformers

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Primary Reformer - Radiant Section - Convection Section

144 vertical mounted high

alloy steel(288 tubes in total).

576 forced draught burners in 6 rows.

8 Coils in Convection Section.

Primary Ref0rmer

Source & References

Introduction

Conclusion

Steam Reformers

Process Gas Inlet

Process Gas Outlet

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Inlet Outlet

Temperature 500oC 773 oC

Pressure 35.7 kg/cm2 33.4 kg/cm2

Composition(in % Dry basis)

CH4 94.03 13.0

H2 3.48 67.64

N2 1.64 0.55

Ar 0.01 0.01

CO - 8.29

CO2 0.15 10.51

C2H6 0.66 -

C3H8 0.03 -

Contd..

Source & References

Introduction

Conclusion

Steam Reformers

Catalyst Tube I.D. / O.D. – 129/150 mm

Catalyst tube length – 12090 mm

Catalyst bed height in tubes -11,370 mm

Tube Material – 25Cr 35Ni Nb Ti

Maximum tube wall temperature – 905 0 C

Actual design temperature – 872.5 0 C

Current tube wall temperature – 875 0 C

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Catalyst Tubes

Source & References

Introduction

Conclusion

Steam Reformers

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Primary Reformer Burner

Combustion Air

RLNG Fuel

Combustion Air Source & References

Introduction

Conclusion

Steam Reformers

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Burner Specification

Type: Radol MKILP1 Combustion Air: Forced Draught Combustion Air Temperature Designed: 280 oC Designed Excess Air: 10% Normal Excess Air: 5% Designed Air Pressure: 200 mmWg Maximum Furnace Draught: -15 mmWg Design Gas Pressure(Fuel): 1kg/cm2g Burner Duty, Maximum: 463,000 KCal/hr Burner Duty, Normal: 370,500 KCal/hr Burner Duty, Minimum: 92,500 Kcal/hr

• Burner Duties given above include the preheating of fuel

of combustion air. Source & References

Introduction

Conclusion

Steam Reformers

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Catalyst Shape: Ribbed Ring

Top Half Bottom Half

Ni 25 15-20

MgO Balance 20-25

Al2O3 11 55-60

SiO2 - <100 ppm

S - <2000 ppm

Cl- <50 ppm -

Bulk Density 0.9-1.0 kg/lt 0.9-1.0 kg/lt

Make HTAS Denmark HTAS Denmark

Type RKNR R-67-7H

Volume 21.4 m3 21.4 m3

Radial Crushing Strength 15-20 kg/cm 30 kg/cm

Catalyst

Source & References

Introduction

Conclusion

Steam Reformers

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Secondary Reformers

Reformer Outlet

Mixing and combustion of reformed process gas with process air.

- Mixing of N2 - Utilization of O2 by combustion - Temperature raised to 1200 o C

Amount of air(nitrogen) addition

depend on desired N2 to H2 ratio.

Thermo indicative coating.

Normal skin temperature 160 o C (designed 300o C)

Feed Gas

Process Air

Source & References

Introduction

Conclusion

Steam Reformers

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Inlet Outlet

Temperature 773 959

Pressure 33.4 32.8

Air entering in secondary reformer at temperature 5550 C

and pressure 34 kg/cm2

Composition(in % Dry basis)

CH4 13 0.45

H2 67.64 55.92

N2 0.55 23.29

Ar 0.01 0.28

CO 8.29 12.41

CO2 10.51 7.65

Operating Conditions

Source & References

Introduction

Conclusion

Steam Reformers

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Size and Shape: 11x5 mm (Ribbed Rings)

Ni 8-10%

Al2O3 87-90%

SiO2 <0.05 %

S < 0.05%

Make UCI, USA

Type C-14-02-RR

Volume 39 m3

Size 16mm x 16mm x 6mm

Shape Ribbed Rings

Bulk Density 1.1 + .1 kg/lt

Catalyst

Source & References

Introduction

Conclusion

Steam Reformers

Shape of the catalyst Ni based Catalyst Vertical and side fired furnaces Ni content of catalyst influenced by process gas

composition and reaction temperature CO and CO2 content in process gas after primary

reformer and secondary reformer

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Source & References

Introduction

Conclusion

Steam Reformers

Conclusion

Ammonia II Training Manual HTAS Manual Volume I and Volume VI Fertilizer Science and Technology Series, Volume II : Ammonia

Part I, Slack & James HTAS Reforming Catalyst Manual http://resources.schoolscience.co.uk/johnsonmatthey/page17.ht

m http://www.chemengservices.com/tech35.html Hydrogen production by steam reforming of LNG over Ni/Al2O3-

ZrO2 catalysts: Effect of ZrO2 and preparation method of Al2O3-ZrO2 by Jeong Gil Seo, Min Hye Youn, Sunyoung Park, Joohyung Lee, Sang Hee Lee, Howon Lee and In Kyu Song

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Source & References

Source & References

Introduction

Conclusion

Steam Reformers

Thank you..

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12/8/2011

Steam Reforming- Presented by Sanjay Katheria 502237