Topsoe WSA technology for small compact sulfuric acid production unitsCOBRAS 2015, Fortaleza, Brazil

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Presentation – main contents

• Introduction to Rio Seco• Introduction to the WSA technology• Typical WSA plant design• WSA plant equipment• References• Summary

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Rio Seco

• Part of the large Buenaventura group in Peru• Procesadora Industrial Rio Seco S. A. plant, Hural 100 km from Lima• Processing of silver ore by use of among other things sulfuric acid• Magnesium sulphates are produced and an H2S stream is generated which needs

cleaning• The H2S stream and sulfur is burned in WSA plant for making 60 MTPD of 98 % acid

for local consumption at the site• Gas cleaning and acid production in same unit• High pressure steam from the WSA process is used for electricity production• Remote location so local electricity production has value• Avoid authority inspections/problems related to buying acid

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What is WSA?Wet gas Sulfuric AcidA catalytic process for purification of sulfur- containing streams while producing concentrated sulfuric acid

SH2SRSHCOSCS2

SO2

SO3

(NH4)2SO4

H2SO4

Sulfuric acid

Cleaned gas

HP Steam

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Why WSA?

• Up to 99.95 % of the sulfur content is recovered• Treats the mixture of H2S and S• Sulfur is recovered as concentrated sulfuric acid of commercial grade• No waste products• NH3 and hydrocarbons are accepted in the feed gas• Excellent heat management• Simple lay-out, few components• Attractive operating cost and lower investment than competing technologies

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Chemical reactions – WSA for H2S gas

H2S

SO2

SO3

H2SO4 (gas)

H2SO4 (liquid)

Combustion H2S + 1.5 O2 → SO2 + H2O + heat

Conversion SO2 + 0.5 O2 → SO3 + heat

SO3 + H2O → H2SO4 (gas) + heat

H2SO4 (gas) → H2SO4 (liquid) + heat

Gas cooling

Condensation

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WSA process lay-out, H2S gas

H2S gas

SO2 converter

Acid cooler

Product acid

Combustion air

Stack gas

Blower

WSAcondenser

Interbedcooler

Interbedcooler

Gascooler

Combustor

Air

Blower

Reaction:

H2SO4 (g) → H2SO4 (liq)

Reaction:

SO3 + H2O → H2SO4 (g)

BFW Steamdrum

WHB

Reaction:

SO2 + ½O2 → SO3

Reaction:

H2S + 1½O2 → SO2 + H2O CW

Superheated steam

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Rio Seco WSA plant process layout

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WSA plant lay-out, H2S based

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Rio Seco WSA plant

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Rio Seco WSA plant

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Combustor and waste heat boiler

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Rio Seco combustor and waste heat boiler

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Rio Seco burner internals including waste heat boiler internal by-pass

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SO2 converter

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SO2 conversion catalyst series VK-W

VK-WSX / VK-WL9 mm Daisy

VK-WSA25 mm Daisy

VK-WSA / VK-WH12 mm Daisy

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WSA condenser

Cooling air inlet

Clean gas outlet

Hot air outletSO3 gas inlet

Sulphuric acid

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WSA condenser – modular construction

Hot Air Outlet

Cooling Air Inlet

Clean Gas Outlet

Product Acid Outlet

Acid Gas Inlet

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WSA condenser design

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Rio Seco sulfuric acid product cooler

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Rio Seco plant data

• Acid capacity is 60 MTPD of 98 % acid. 50 % from H2S gas and 50 % from burning of S

• Electricity production approx 1 MW(e)• Foot print is 30 m x 18 m• Cooling water consumption (circulating) is very low• H2S waste gas incinerated with the sulphur

• H2S = 28 % vol• N2 = 25 % vol• CO2 = 45 % vol• H2O = 2 % vol

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Typical scope of supply

• License package• Basic engineering• Proprietary equipment• Catalyst• Supervision during erection and commissioningOptional:• Detailed engineering• Supply of other equipment

• WSA condenser internals• Acid vessel, pumps and cooler• Acid piping and instruments• Interbed heat exchangers• Process gas cooler• Mist control units

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WSA plants – applications

• Oil refining (39)• Coking (33)• Gasification (31)• Metallurgical industry (14)• Viscose fibre industry (8)• Other applications (10)• Total (135) – From the 135 plants 11 plants are burning sulphur as feed

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WSA/SNOXTM references

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3

4

1

2

6

1

13

1415

11 5

4

9 10

3

56

7

8

1

2

45

6

8 9

5

6

2

3

5

2

1

3

7

8

12

4

3

74

2

19

9

10

Oil refining

Coking

Gasification

Metallurgy

Viscose

Sundry applications

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4

1

7

3

17

16

118

9

20

10

11

13

12

10

5

11

17

15

12

14

24

2322

12

26

25

27

16

21

January 2014

15 1619 18

6

14

13

17

2021

19 1822

7

28

20

23

8

29

13

31

23

2825 2726

30

6 7

2532

33

2424

21

34

2931

9

30 35

14

26

27

36

3738

2829

3233

Acid production: 4 – 1,140 MTPDMore than 135 references

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WSA technology summary

• Clean, proven and reliable technology• No consumption of chemicals or other additives, and no production of waste products• High conversion of sulfur containing feeds into commercial-grade sulfuric acid, with

possibility for NOx reduction if required• Effective heat recovery• Simple layout with relatively small plot area• Attractive operating economy