This presentation will discuss the different technical solutions including advantages and disadvantages users will have to face. It will show a few examples of experiences learned in different plants world-wide as well as some guidance how to find the best possible pumping solution.

1. 18. – 21. October 2015
DIVISION RHEINHÜTTE PUMPEN
COBRAS, IX Brazilian Congress of Sulfuric Acid
Fortaleza, Brazil
SULPHURIC ACID:
A CHALLENGE FOR MATERIALS
AND SEALING SYSTEMS FOR
CENTRIFUGAL PUMPS

2. CONTENT
2
Introduction
Overview
Materials
Pump Design & Sealing Systems

3. Rheinhütte Pumpen are experts for sophisticated
pumping applications for corrosive, abrasive and
toxic fluids.
■ Our unique material expertise
■ Our broad variety of materials
■ And more than 150 years of experience (1857)
always offer you the right solution:
Pumps which reliably convey the most difficult
fluids throughout demanding industries -
worldwide.
COMPANY PROFILE
ABOUT US
3

4. COMPANY PROFILE
GLOBAL EXPERTISE
 Headquarter in
Wiesbaden / Germany
 Production plants in
• Wiesbaden and
Rennerod / Germany
• Cataguases / Brazil
• Shanghai / China
• Odessa / Florida
 Worldwide more than
70 Sales Offices and
Service Depots
4
Rheinhütte Pumpen sites
Group-affiliated-companies
Sales companies
HQ in Germany:
2 Factories
300 employees
Brazil:
Cataguases
90 employees

5. COMPANY PROFILE
FACTORY CATAGUASES

6. COMPANY PROFILE
FACTORY CATAGUASES

7. CONTENT
7
Introduction
Overview
Materials
Pump Design & Sealing Systems

8. OVERVIEW
8
Materials
Metal
Plastic
Sealing Systems
Gland Packing
Pump Design
Vertical
Horizontal Mechanical Seal
Mag Drives
Hydrodynamic Seal
Sulphuric Acid
Ceramic

9. CONTENT
9
Introduction
Overview
Materials
Pump Design & Sealing Systems

10. MATERIALS
OVERVIEW
Siguss
PTFE
nur bis 180°C
Concentration H SO in %2 4
Temperature
20
50
100
200
300
0 50 100
[°C]
Boiling line
Plastic
PP, Pe1000, PVDF, ETFE
Ferretic&
specialmetal
alloys
Special metal alloys like:
•SX
•Saramet 35
•Lewmet
•1.4136S
1.4408
1.4408

11. MATERIALS
CORROSION BEHAVIOR OF SULPHURIC ACID
0 10 20 30 40 50 60 70 80 90 100
Concentration [%]
Relativecorrosiveness
low
high

12. MATERIALS
CORROSION OF PLASTIC MATERIALS IN H2SO4
ISO Corrosion Curve H2SO4
0
25
50
75
100
125
150
175
200
225
250
275
300
325
350
0 10 20 30 40 50 60 70 80 90 100
Concentration [%]
Temperature[°C]
Boiling curve sulphuric acid
Corrosion curve PP
Corrosion curve PE UHMW
Corrosion curve PVDF
Corrosion curve PTFE / PFA
Corrosion curve ETFE
no responsibility is taken for the correctness of this information !

13. MATERIALS
SILICON CAST IRON (15% SILICON) - CORROSION RATE PER YEAR
20
40
60
80
100
120
140
160
180
200
220
240
260
280
300
320
340
0 10 20 30 40 50 60 70 80 90 100
T(°C)
< 0,4 mm/a
< 0,02 mm/a
< 0,1 mm/a
%
H2SO4
Source: Rheinhuette technical
information 1
Siguss is resistant against corrosion of sulphuric acid at all
concentrations and temperatures

14. MATERIALS
CORROSION AND ROTATING SPEED
Corrosion rate of SS 316 for different concentrations of H2SO4 at
different rotation speed.
0,01
0,1
1
10
100
0 10 20 30 40 50 60 70 80 90 100
0 m/s
2 m/s
4 m/s
25° C
Corrosionrateinmmperyear
Concentration in % H2SO4

15. MATERIALS
UNIFORM CORROSION
■ Typical for metallic materials
■ Uniform (homogeneous) material loss on the surface
■ Corrosion rate is calculable by corrosion tests
■ Max. 0,5 mm per year – resistant material
■ Iso-corrosion-curves often available
■ This corrosion form is acceptable
Please note
■ Especially for mixtures – corrosion rates of the single
components are not summable!
■ Already traces can boost, but also inhibit the corrosion rate!
15

16. MATERIALS
H2SO4 ISO CORROSION CURVES
original
resistantnot resistant
0,1mm/a curve – static tests
note: no flow and no impurities
Source: Outokumpu stainless corrosion handbook
DIN EN 1.4571
= 316 Ti

17. MATERIALS
H2SO4 AND ADDITIVES
The corrosiveness of sulphuric acid could be significantly different, by the presence
of various additives.
Some matters inhibit and other matters enforce the corrosiveness of sulphuric acid.
Inhibiting effect
- CuSO4
- FeSO4
- Nitrates / HNO3
Enforcing effect
- SO2
- Chlorides
- Traces of other acids (HCl)
Example: 1.4539 (904L) Corrosion rate
in 20% H2SO4 at 50 °C 0,01 mm/a
in 500 ppm Cl- at 50 °C 0,0025 mm/a
in 20% H2SO4 with 500 ppm Cl- at 50 °C 0,1 mm/a
1.4571 (316Ti) Corrosion rate
in 20% H2SO4 at 50 °C 1,3 mm/a
in 20% H2SO4 with 500 ppm CuSO4 at 50 °C 0,01 mm/a

18. MATERIALS
EROSION (CORROSION)
Erosion is a known problem for flowing media
■ High flow rates may cause eddies at obstacles,
defects or at turnarounds
■ Increased material losses aground of eddies
■ Typical are “erosion scars” like tears
Specific liquids enforce the effect of erosion!
Serious consequence could be an erosion corrosion

19. MATERIALS
EROSION - CORROSION IN DETAIL
■ Effect is known for metallic and plastic materials
■ Localized (inhomogeneous) material loss on the surface
■ Only in regions with high flow rates
■ Flow washes the passive layer away – velocity of the
removal is higher as the velocity of the reformation
■ Corrosion rate by flowing media is higher than in static media
■ The harder the material, the higher the resistance against
erosion corrosion
■ This corrosion form is not acceptable

20. MATERIALS
EROSION – CORROSION ON A PUMP IMPELLER
• Mag-Drive pump
• Highly alloyed Austenitic
• 96% H2SO4 at 30 °C
• In application for 3 years

21. CONTENT
21
Introduction
Overview
Materials
Pump Design & Sealing Systems

22. SEALING SYSTEMS
OVERVIEW
Concentration H SO in %2 4
Temperature
20
50
100
200
300
0 50 100
[°C]
Boiling line
Vertical or
Hydrodynamic
Mag-Drive
Mechanical Seal

23. PUMP DESIGN
VERTICAL PUMP TYPE VS4 OR VS1, STRONG ACID CIRCULATING PUMPS
Photo: Lewis Pumps Photo: Ensival-Moret

24. 24
Corrosion resistant sleeve bearing lubricated by the fluid with
different groove systems available
Double volute casing to balance
radial loads on the sleeve
bearing system
PUMP DESIGN
MTBF - VERTICAL PUMP STRONG ACID CIRCULATING PUMPS

25. 25
PUMP DESIGN
MTBF - VERTICAL PUMP STRONG ACID CIRCULATING PUMPS
Ceramic catalyst
always an
issue for sleeve
bearing system

26. 26
PUMP DESIGN
MTBF - VERTICAL PUMP STRONG ACID CIRCULATING PUMPS

27. 27
PUMP DESIGN
MTBF - VERTICAL PUMP STRONG ACID CIRCULATING PUMPS

28. 28
PUMP DESIGN
MTBF - VERTICAL PUMP STRONG ACID CIRCULATING PUMPS
Groove system with high pressure
injection from discharge.
Gap clearance can be adjusted

29. PUMP DESIGN
HORIZONTAL WEAK ACID PLASTIC PUMP
Cast iron armour
Solid plastic

30. PUMP DESIGN
PLASTIC IMPELLER

31. PUMP DESIGN
MASSIV PLASTIC CASING

32. PUMP DESIGN
HORIZONTAL WEAK ACID PUMP
10% H2SO4
with Ni, Cu &
Co powder
Material: PE
T: 70°C
Q: 2500 m³/h
H: 29 m
Motor: 280 kW

33. PUMP DESIGN
HORIZONTAL WEAK ACID PUMP
10% H2SO4
with Ni, Cu &
Co powder
Material: PE
T: 70°C
Q: 2500 m³/h
H: 29 m
Motor: 280 kW

34. PUMP DESIGN
SILICON CAST IRON PUMP WITH HYDRODYNAMIC SHAFT SEAL
Hydrodynamic shaft seal
with up to 3 expellers
Standstill seal:
grease, pneumatic, packing
Concret
filling
Silicon cast iron
Cast iron armour

35. PUMP DESIGN
HORIZONTAL MAGNETIC DRIVEN METAL PUMP
Critical
Components:
-Spacer Can
-Inner Rotor
Inner rotor
Spacer can
Materials:
-SX
-Hastelloy C4
-1.4539 (904L)
-1.4136S

36. PUMP DESIGN
ACID CIRCULATING PUMP WITH AN „INDUCER“ IMPELLER
Hydrodynamic shaft seal
with up to 3 expellers
Pneumatic standstill
seal
Concret filling
Silicon cast iron
Cast iron armour

37. PUMP DESIGN
ACID CIRCULATING PUMP WITH AN „INDUCER“ IMPELLER
30 - 80% H2SO4
with metal sulfate
chrystals
T: 50 - 190°C
Q: 1500 m³/h
H: 3 m
DN 500
A Special Pump
for a Special
Application
German
History

38. PUMP DESIGN
ACID CIRCULATING PUMP WITH AN „INDUCER“ IMPELLER
30 - 80% H2SO4
with metal sulfate
chrystals
T: 50 - 190°C
Q: 1500 m³/h
H: 3 m
DN 500
A Special Pump
for a Special
Application
German
History

39. REFERENCES
EUROPEAN END-USERS AN ENGINEERING COMPANIES
39

40. REFERENCES
■ Vertical Acid Pumps: 237 units
■ Horizontal Acid Pumps: 952 units
NUMBER OF DELIVERED PUMPS IN H2SO4 SERVICE SINCE 2004
40

41. THANK YOU!