Sulfuric Acid Manufacture, 2nd Edition

Preface

1. Overview

1.1 Catalytic oxidation of SO_{2} to SO_{3}

1.2 H_{2}SO_{4} production

1.3 Industrial flowsheet

1.4 Sulfur burning

1.5 Metallurgical offgas

1.6 Spent acid regeneration

1.7 Sulfuric acid product

1.8 Recent developments

1.9 Alternative processes

1.10 Summary

References

Suggested reading

2. Production and consumption

2.1 Uses

2.2 Acid plant locations

2.3 Price

2.4 Summary

References

Suggested reading

3. Sulfur burning

3.1 Objectives

3.2 Sulfur

3.3 Molten sulfur delivery

3.4 Sulfur atomizers and sulfur burning furnaces

3.5 Product gas

3.6 Heat recovery boiler

3.7 Summary

References

Suggested reading

4. Metallurgical offgas cooling and cleaning

4.1 Initial and final SO_{2} concentrations

4.2 Initial and final dust concentrations

4.3 Offgas cooling and heat recovery

4.4 Electrostatic collection of dust

4.5 Water scrubbing (Tables 4.5 and 4.6)

4.6 H_{2}O(g) removal from scrubber exit gas (Tables 4.5 and 4.6)

4.7 Summary

References

Suggested reading

5. Regeneration of spent sulfuric acid

5.1 Spent acid compositions

5.2 Spent acid handling

5.3 Decomposition

5.4 Decomposition furnace product

5.5 Optimum decomposition furnace operating conditions

5.6 Preparation of offgas for SO_{2} oxidation and H_{2}SO_{4} making

5.7 Summary

References

Suggested Reading

6. Dehydrating air and gases with strong sulfuric acid

6.1 Chapter objectives

6.2 Dehydration with strong sulfuric acid

6.3 Dehydration reaction mechanism

6.4 Residence times

6.5 Recent advances

6.6 Summary

References

7. Catalytic oxidation of SO_{2} to SO_{3}

7.1 Objectives

7.2 Industrial SO_{2} oxidation

7.3 Catalyst necessity

7.4 SO_{2} oxidation “heatup” path (Chapter 11)

7.5 Industrial multicatalyst bed SO_{2} oxidation (Tables 7.2–7.7)

7.6 Industrial operation (Table 7.2)

7.7 Recent advances

7.8 Summary

References

8. SO_{2} oxidation catalyst and catalyst beds

8.1 Catalytic reactions

8.2 Maximum and minimum catalyst operating temperatures

8.3 Composition and manufacture

8.4 Choice of size and shape

8.5 Catalyst bed thickness and diameter

8.6 Gas residence times

8.7 Catalyst bed temperatures

8.8 Catalyst bed maintenance

8.9 Summary

References

Suggested reading

9. Production of H_{2}SO_{4}(ℓ) from SO_{3}(g)

9.1 Objectives

9.2 Sulfuric acid rather than water

9.3 Absorption reaction mechanism

9.4 Industrial H_{2}SO_{4} making (Tables 9.3–9.8)

9.5 Choice of input and output acid compositions

9.6 Acid temperature

9.7 Gas temperatures

9.8 Operation and control

9.9 Double contact H_{2}SO_{4} making (Tables 19.3 and 23.2)

9.10 Intermediate versus final H_{2}SO_{4} making

9.11 Summary

References

Suggested reading

Break

10. Oxidation of SO_{2} to SO_{3}—Equilibrium curves

10.1 Catalytic oxidation

10.2 Equilibrium equation

10.3 *K*E as a function of temperature

10.4 *K*E in terms of *% SO*2*oxidized*

10.5 Equilibrium *% SO*_{2} oxidized as a function of temperature

10.6 Discussion

10.7 Summary

10.8 Problems

Reference

11. SO_{2} oxidation heatup paths

11.1 Heatup paths

11.2 Objectives

11.3 Preparing a heatup path—The first point

11.4 Assumptions

11.5 A specific example

11.6 Calculation strategy

11.7 Input SO_{2}, O_{2}, and N_{2} quantities

11.8 Sulfur, oxygen, and nitrogen molar balances

11.9 Enthalpy balance

11.10 Calculating level L quantities

11.11 Matrix calculation

11.12 Preparing a heatup path

11.13 Feed gas SO_{2} strength effect

11.14 Feed gas temperature effect

11.15 Significance of heatup path position and slope

11.16 Summary

11.17 Problems

12. Maximum SO_{2} oxidation: Heatup path-equilibrium curve intercepts

12.1 Initial specifications

12.2 *% SO*_{2} oxidized-temperature points near an intercept

12.3 Discussion

12.4 Effect of feed gas temperature on intercept

12.5 Inadequate *% SO*_{2} oxidized in first catalyst bed

12.6 Effect of feed gas SO_{2} strength on intercept

12.7 Minor influence—Equilibrium gas pressure

12.8 Minor influence—O_{2} strength in feed gas

12.9 Minor influence—CO_{2} in feed gas

12.10 Catalyst degradation, SO_{2} strength, and feed gas temperature

12.11 Maximum feed gas SO_{2} strength

12.12 Exit gas composition ≡ intercept gas composition

12.13 Summary

12.14 Problems

13. Cooling first catalyst bed exit gas

13.1 First catalyst bed summary

13.2 Cooldown path

13.3 Gas composition below equilibrium curve

13.4 Summary

13.5 Problem

Hints

14. Second catalyst bed heatup path

14.1 Objectives

14.2 *% SO*_{2} oxidized redefined

14.3 Second catalyst bed heatup path

14.4 A specific heatup path question

14.5 Second catalyst bed input gas quantities

14.6 S, O, and N molar balances

14.7 Enthalpy balance

14.8 Calculating 760 K (level L) quantities

14.9 Matrix calculation and result

14.10 Preparing a heatup path

14.11 Discussion

14.12 Summary

14.13 Problem

15. Maximum SO_{2} oxidation in a second catalyst bed

15.1 Second catalyst bed equilibrium curve equation

15.2 Second catalyst bed intercept calculation

15.3 Two bed SO_{2} oxidation efficiency

15.4 Summary

15.5 Problems

Hints

16. Third catalyst bed SO_{2} oxidation

16.1 2-3 Cooldown path

16.2 Heatup path

16.3 Heatup path-equilibrium curve intercept

16.4 Graphical representation

16.5 Summary

16.6 Problems

17. SO_{3} and CO_{2} in feed gas

17.1 SO_{3}

17.2 SO_{3} effects

17.3 CO_{2}

17.4 CO_{2} effects

17.5 Summary

17.6 Problems

18. Three catalyst bed acid plant

18.1 Calculation specifications

18.2 Example calculation

18.3 Calculation results

18.4 Three catalyst bed graphs

18.5 Minor effect—SO_{3} in feed gas

18.6 Minor effect—CO_{2} in feed gas

18.7 Minor effect—Bed pressure

18.8 Minor effect—SO_{2} strength in feed gas

18.9 Minor effect—O_{2} strength in feed gas

18.10 Summary of minor effects

18.11 Major effect—Catalyst bed input gas temperatures

18.12 Discussion of book’s assumptions

18.13 Summary

Reference

19. After-H_{2}SO_{4}-making SO_{2} oxidation

19.1 Double contact advantage

19.2 Objectives

19.3 After-H_{2}SO_{4}-making calculations

19.4 Equilibrium curve calculation

19.5 Heatup path calculation

19.6 Heatup path-equilibrium curve intercept calculation

19.7 Overall SO_{2} oxidation efficiency

19.8 Double/single contact comparison

19.9 Summary

19.10 Problems

Reference

20. Optimum double contact acidmaking

20.1 Total *% SO*_{2} oxidized after all catalyst beds

20.2 Four catalyst beds

20.3 Improved efficiency with five catalyst beds

20.4 Input gas temperature effect

20.5 Best bed for Cs catalyst

20.6 Triple contact acid plant

20.7 Summary

Reference

21. Enthalpies and enthalpy transfers

21.1 Input and output gas enthalpies

21.2 H_{2}SO_{4} making input gas enthalpy

21.3 Heat transfers

21.4 Heat transfer rate

21.5 Summary

21.6 Problems

22. Control of gas temperature by bypassing

22.1 Bypassing principle

22.2 Objective

22.3 Gas to economizer heat transfer

22.4 Heat transfer requirement for 480 K economizer output gas

22.5 Changing heat transfer by bypassing

22.6 460 K Economizer output gas

22.7 Bypassing for 460, 470, and 480 K economizer output gas

22.8 Bypassing for 470 K economizer output gas while input gas temperature is varying

22.9 Industrial bypassing

22.10 Summary

22.11 Problems

23. H_{2}SO_{4} making

23.1 Objectives

23.2 Mass balances

23.3 SO_{3} input mass

23.4 H_{2}O(g) input from moist acid plant input gas

23.5 Water for product acid

23.6 Calculation of mass water in and mass acid out

23.7 Interpretations

23.8 Summary

23.9 Problem

24. Acid temperature control and heat recovery

24.1 Objectives

24.2 Calculation of output acid temperature

24.3 Effect of input *acid* temperature

24.4 Effect of input *gas* temperature

24.5 Effect of input gas SO_{3} concentration on output acid temperature

24.6 Adjusting output acid temperature

24.7 Acid cooling

24.8 Target acid temperatures

24.9 Recovery of acid heat as steam

24.10 Steam production principles

24.11 Double-packed bed absorption tower

24.12 Steam injection

24.13 Sensible heat recovery efficiency

24.14 Materials of construction

24.15 Summary

24.16 Problems

References

25. Making sulfuric acid from wet feed gas

25.1 Chapter objectives

25.2 WSA feed Gas

25.3 WSA flowsheet

25.4 Catalyst bed reactions

25.5 Preparing the oxidized gas for H_{2}SO_{4}(ℓ) condensation

25.6 H_{2}SO_{4}(ℓ) condenser

25.7 Product acid composition

25.8 Comparison with conventional acidmaking

25.9 Appraisal

25.10 Alternatives

25.11 Summary

References

Suggested reading

26. Wet sulfuric acid process fundamentals

26.1 Wet gas sulfuric acid process SO_{2} oxidation

26.2 Injection of nanoparticles into cooled process gas

26.3 Sulfuric acid condensation

26.4 Condenser temperature choices

26.5 Condenser acid composition up the glass tube

26.6 Condenser re-evaporation of H_{2}O(ℓ)

26.7 Condenser acid production rate

26.8 Condenser appraisal

26.9 Summary

References

Suggested reading

27. SO_{3} gas recycle for high SO_{2} concentration gas treatment

27.1 Objectives

27.2 Calculations

27.3 Effect of recycle extent

27.4 Effect of recycle gas temperature on recycle requirement

27.5 Effect of gas recycle on first catalyst SO_{2} oxidation efficiency

27.6 Effect of first catalyst exit gas recycle on overall acid plant performance

27.7 Recycle equipment requirements

27.8 Appraisal

27.9 Industrial SO_{3} gas recycle

27.10 Alternatives to gas recycle

27.11 Summary

References

28. Sulfur from tail gas removal processes

28.1 Objectives

28.2 Environmental standards

28.3 Acid plant tail gas characteristics

28.4 Industrial acid plant tail gas treatment methods

28.5 Technology selection (after Hay et al., 2003)

28.6 Capital and operating costs

28.7 Summary

References

29. Minimizing sulfur emissions

29.1 Industrial catalytic SO_{2}+0.5O_{2}→SO_{3} oxidation

29.2 Methods to lower sulfur emissions

29.3 Summary

References

Suggested reading

30. Materials of construction

30.1 Chapter objectives

30.2 Corrosion rate factors for sulfuric acid plant equipment

30.3 Sulfuric acid plant materials of construction

30.4 Summary

References

31. Costs of sulfuric acid production

31.1 Investment costs

31.2 Production costs

31.3 Summary

References

Appendix A. Sulfuric acid properties

A.1 Sulfuric acid specific gravity at constant temperature

A.2 Specific gravity of sulfuric acid at elevated temperatures

A.3 Sulfuric acid freezing points

A.4 Oleum specific gravity

A.5 Electrical conductivity of sulfuric acid

A.6 Absolute viscosity of sulfuric acid

Appendix B. Derivation of equilibrium equation (10.12)

B.1 Modified equilibrium equation

B.2 Mole fractions defined

B.3 Feed and oxidized gas molar quantities

B.4 Mole fractions in oxidized gas

B.5 Equation applicability

B.6 Equilibrium equation

B.7 Equilibrium constant and molar quantities

B.8 Equilibrium and Φ^{E}

Appendix C. Free energy equations for equilibrium curve calculations

C.1 Production of SO_{3}(g) from SO_{2}(g) and O_{2}(g)

C.2 Production of H_{2}SO_{4}(g) from SO_{3}(g) and H_{2}O(g)

Appendix D. Preparation of Fig. 10.2’s equilibrium curve

D.1 Integer temperature calculations

D.2 Second and third catalyst bed equilibrium curves

Appendix E. Proof that volume%=mol% (for ideal gases)

E.1 Definitions

E.2 Characterization of partial volumes

E.3 Equality of volume% and mol%

Appendix F. Effect of CO_{2} and Ar on equilibrium equations (*none*)

F.1 CO_{2}

F.2 Ar

F.3 Conclusions

Appendix G. Enthalpy equations for heatup path calculations

G.1 An example—Enthalpy of SO_{3}(g) at 600 K

G.2 Preparation of equations

References

Appendix H. Matrix solving using Tables 11.2 and 14.2 as examples

Appendix I. Enthalpy equations in heatup path matrix cells

I.1 Example results

Appendix J. Heatup path-equilibrium curve: Intercept calculations

J.1 Calculation strategy

J.2 Worksheet

J.3 Intercept worksheet preparation instructions

J.4 Goal Seek instructions

J.5 Another example

Appendix K. Second catalyst bed heatup path calculations

Appendix L. Equilibrium equation for multicatalyst bed SO_{2} oxidation

L.1 Proof

L.2 Inapplicability

Appendix M. Second catalyst bed intercept calculations

M.1 Calculation strategy

M.2 Specifications (Fig. 14.2)

M.3 Worksheet

M.4 Goal Seek instructions

Appendix N. Third catalyst bed heatup path worksheet

Appendix O. Third catalyst bed intercept worksheet

Appendix P. Effect of SO_{3} in Fig. 10.1’s feed gas on equilibrium equations

P.1 Molar balances

P.2 Total kg mol of oxidized gas

P.3 Mole fractions in oxidized gas

P.4 New equilibrium equation

P.5 *% SO*_{2} oxidized in equilibrium equation

P.6 Equilibrium *% SO*_{2} oxidized as a function of temperature

Appendix Q. SO_{3}-in-feed-gas intercept worksheet

Appendix R. CO_{2}- and SO_{3}-in-feed-gas intercept worksheet

Appendix S. Three-catalyst-bed “converter” calculations

S.1 First catalyst bed calculations (cells A1 through M47)

S.2 Second catalyst bed calculations (cells AA1 through AM47)

S.3 Third catalyst bed calculations (cells BA1 through BM47)

Appendix T. Worksheet for calculating after-intermediate-H_{2}SO_{4}-making heatup path-equilibrium curve intercepts

Appendix U. After-H_{2}SO_{4}-making SO_{2} oxidation with SO_{3} and CO_{2} in input gas

U.1 Equilibrium equation with SO_{3} in after-H_{2}SO_{4}-making input gas

U.2 H_{2}SO_{4} making input gas quantity specification

U.3 H_{2}SO_{4} making exit gas quantity calculation

U.4 Calculation of H_{2}SO_{4} making exit gas volume percents

U.5 Worksheet construction and operation

U.6 Calculation of *% SO*_{2} oxidized after all catalyst beds

Appendix V. Moist air in H_{2}SO_{4} making calculations

V.1 Calculation

Appendix W. Calculation of H_{2}SO_{4} making tower mass flows

W.1 Input and output gas specifications

W.2 Input SO_{3}(g) equation

W.3 Input and output acid composition equations

W.4 Total mass balance equation

W.5 Sulfur balance equation

W.6 Solving for flows

W.7 Effect of output acid mass% H_{2}SO_{4} on input and output acid flows

Appendix X. Equilibrium equations for SO_{2}, O_{2}, H_{2}O(g), N2 feed gas

X.1 Equilibrium equations

X.2 Modified equilibrium equations

X.3 Mole fractions defined

X.4 Feed and oxidized gas molar quantities

X.5 Preparing Eqs. (X.1) and (X.2) from Eqs. (X.19) and (X.21)

Appendix Y. Cooled first catalyst bed exit gas recycle calculations

Y.1 Exit gas temperature without recycle

Y.2 Recycle calculation setup

Y.3 Recycle matrix (Table Y.2)

Y.3.2 Result

Y.4 Recalculation to steady state

Y.5 Different feed and recycle temperatures

Y.6 Third catalyst bed exit gas recycle calculations

Answers to numerical problems

Chapter 10

Chapter 11

Chapter 12

Chapter 13

Chapter 14

Chapter 15

Chapter 16

Chapter 17

Chapter 19

Chapter 21

Chapter 22

Chapter 23

Chapter 24

Index