Post on 11-Feb-2017
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
IntroductionOverviewMaterialsPump Design & Sealing Systems
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
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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
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Rheinhütte Pumpen sitesGroup-affiliated-companiesSales companies
HQ in Germany:2 Factories300 employees
Brazil:Cataguases90 employees
COMPANY PROFILE
FACTORY CATAGUASES
COMPANY PROFILE
FACTORY CATAGUASES
7
CONTENT
IntroductionOverviewMaterialsPump Design & Sealing Systems
OVERVIEW
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Materials
Metal
Plastic
Sealing Systems
Gland Packing
Pump Design
Vertical
Horizontal Mechanical Seal
Mag Drives
Hydrodynamic Seal
Sulphuric Acid
Ceramic
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CONTENT
IntroductionOverviewMaterialsPump Design & Sealing Systems
MATERIALS
OVERVIEW
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SigussPTFEnur bis 180°C
Concentration H SO in %2 4
Tem
pera
ture
20
50
100
200
300
0 50 100
[°C]
Boiling line
PlasticPP, Pe1000, PVDF, ETFE
Ferre
tic &
spec
ial m
etal
allo
ys
Special metal alloys like:
•SX•Saramet 35•Lewmet•1.4136S
1.4408
1.4408
MATERIALS
CORROSION BEHAVIOR OF SULPHURIC ACID
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0 10 20 30 40 50 60 70 80 90 100
Concentration [%]
Rel
ativ
e co
rros
iven
ess
low
high
Iron base materials
Plastics
Ceramics
MATERIALSCORROSION 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 [%]
Tem
pera
ture
[°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 !
MATERIALS
SILICON CAST IRON (15% SILICON) - CORROSION RATE PER YEAR
20406080
100120140160180
200220240260280
300320340
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
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
Cor
rosi
on ra
te in
mm
per
yea
r
Concentration in % H2SO4
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!
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MATERIALSH2SO4 ISO CORROSION CURVES
original
resistantnot resistant
0,1mm/a curve – static testsnote: no flow and no impurities
Source: Outokumpu stainless corrosion handbook
DIN EN 1.4571= 316 Ti
MATERIALSH2SO4 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 ratein 20% H2SO4 at 50 °C 0,01 mm/a in 500 ppm Cl- at 50 °C 0,0025 mm/ain 20% H2SO4 with 500 ppm Cl- at 50 °C 0,1 mm/a
1.4571 (316Ti) Corrosion ratein 20% H2SO4 at 50 °C 1,3 mm/ain 20% H2SO4 with 500 ppm CuSO4 at 50 °C 0,01 mm/a
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
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
MATERIALS
EROSION – CORROSION ON A PUMP IMPELLER
MAG-DRIVE PUMP HIGHLY ALLOYED AUSTENITIC96% H2SO4 AT 30 °C IN APPLICATION FOR 3 YEARS
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CONTENT
IntroductionOverviewMaterialsPump Design & Sealing Systems
SEALING SYSTEMS
OVERVIEW
Concentration H SO in %2 4
Tem
pera
ture
20
50
100
200
300
0 50 100
[°C]
Boiling line
Vertical orHydrodynamic
Mag-Drive
Mechanical Seal
PUMP DESIGN
VERTICAL PUMP TYPE VS4 OR VS1, STRONG ACID CIRCULATING PUMPS
Photo: Lewis Pumps Photo: Ensival-Moret
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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
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PUMP DESIGN
MTBF - VERTICAL PUMP STRONG ACID CIRCULATING PUMPS
Ceramic catalyst always anissue for sleeve bearing system
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PUMP DESIGN
MTBF - VERTICAL PUMP STRONG ACID CIRCULATING PUMPS
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PUMP DESIGN
MTBF - VERTICAL PUMP STRONG ACID CIRCULATING PUMPS
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PUMP DESIGN
MTBF - VERTICAL PUMP STRONG ACID CIRCULATING PUMPS
Groove system with high pressure injection from discharge.
Gap clearance can be adjusted
PUMP DESIGN
HORIZONTAL WEAK ACID PLASTIC PUMP
Cast iron armourSolid plastic
PUMP DESIGN
PLASTIC IMPELLER
PUMP DESIGN
MASSIV PLASTIC CASING
PUMP DESIGN
HORIZONTAL WEAK ACID PUMP
10% H2SO4
with Ni, Cu &Co powder
Material: PET: 70°CQ: 2500 m³/hH: 29 mMotor: 280 kW
PUMP DESIGN
HORIZONTAL WEAK ACID PUMP
10% H2SO4
with Ni, Cu &Co powder
Material: PET: 70°CQ: 2500 m³/hH: 29 mMotor: 280 kW
PUMP DESIGN
SILICON CAST IRON PUMP WITH HYDRODYNAMIC SHAFT SEAL
Hydrodynamic shaft sealwith up to 3 expellers
Standstill seal:grease, pneumatic, packing
Concretfilling
Silicon cast iron
Cast iron armour
PUMP DESIGN
HORIZONTAL MAGNETIC DRIVEN METAL PUMP
CriticalComponents:-Spacer Can-Inner Rotor
Inner rotor
Spacer can
Materials:-SX-Hastelloy C4-1.4539 (904L)-1.4136S
PUMP DESIGN
ACID CIRCULATING PUMP WITH AN „INDUCER“ IMPELLER
Hydrodynamic shaft sealwith up to 3 expellers
Pneumatic standstillseal
Concret filling
Silicon cast iron
Cast iron armour
PUMP DESIGN
ACID CIRCULATING PUMP WITH AN „INDUCER“ IMPELLER
30 - 80% H2SO4
with metal sulfatechrystals
T: 50 - 190°CQ: 1500 m³/hH: 3 mDN 500
A Special Pumpfor a SpecialApplication
GermanHistory
PUMP DESIGN
ACID CIRCULATING PUMP WITH AN „INDUCER“ IMPELLER
30 - 80% H2SO4
with metal sulfatechrystals
T: 50 - 190°CQ: 1500 m³/hH: 3 mDN 500
A Special Pumpfor a SpecialApplication
GermanHistory
39
REFERENCES
EUROPEAN END-USERS AN ENGINEERING COMPANIES
40
REFERENCES
■ Vertical Acid Pumps: 237 units
■ Horizontal Acid Pumps: 952 units
NUMBER OF DELIVERED PUMPS IN H2SO4 SERVICE SINCE 2004
THANK YOU!