Sulphuric Acid: A Challenge for Materials and Sealing ... Acid: A Challenge for Materials and Sealing Systems for Centrifugal Pumps AIChE Clearwater Convention 2010; Dr. Jürgen Weinerth

Sulphuric Acid: A Challenge for Materials and SealingSystems for Centrifugal Pumps

AIChE Clearwater Convention 2010; Dr. Jürgen Weinerth

SulphuricSulphuric AcidAcid: :

A A ChallengeChallenge forfor Materials and Materials and SealingSealing Systems Systems forfor CentrifugalCentrifugal

PumpsPumps

Dr. Juergen Dr. Juergen WeinerthWeinerthFriatecFriatec AGAG -- Division Division Rheinhuette Rheinhuette PumpenPumpen

RheingaustrasseRheingaustrasse 96 96 –– 989865203 Wiesbaden, Germany65203 Wiesbaden, Germany



Overview

Materials

Pump Design & Sealing Systems

Contents



Materials

Metal

Plastic

Sealing Systems

Gland Packing

Pump Design

Vertical

Horizontal Mechanical Seal

Mag Drives

Hydrodynamic Seal

Sulphuric Acid

Overview

Ceramic



Overview

Materials


Contents



Siguss

PTFEnur 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

alloy

s

1.4408

1.4408

Special metal alloyslike:

SXSaramet 35Lewmet1.4136S

Materials

Overview



Boiling 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 100Concentration [%]

Tem

pera

ture

[°C

]Boiling curve Sulphuric acid Corrosion curve PPCorrosion curve HD-PE 1000Corrosion curve PVDFCorrosion curve PTFE / PFACorrosion curve ETFE

Materials

Corrosion of Plastic Materials in H2SO4



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

% H2SO4

mm

/aC

orro

sion

rate

in m

m p

er y

ear

Concentration in

Materials

Corrosion and Rotation Speed



Overview

Materials


Contents



Concentration H SO in %2 4

Tem

pera

ture

20

50

100

200

300

0 50 100

[°C]

Boiling line

Vertical orHydrodynamic

Mag-Drive

SealingSystems

Mechanical Seal

Overview



PumpDesign

Vertical “Strong” Acid Circulating Pumps

Photo: Lewis PumpsTM Photo: Ensival-Moret



PumpDesign

Horizontal “Weak” Acid Plastic Pumps

Cast iron armourSolid plastic



PumpDesign

Plastic Impeller Design



PumpDesign

Massive Plastic Casing



PumpDesign

10% H2SO4with Ni, Cu &Co powder

Material: PET: 70°CQ: 2500 m³/hH: 29 mMotor: 280 kW




PumpDesign


10% H2SO4with Ni, Cu &Co powder

Material: PET: 70°CQ: 2500 m³/hH: 29 mMotor: 280 kW



Ceramic Pumps

PumpDesign

SilicateceramicFrikorundTM

Mixed acidsat anyconcentrationwith solids(e.g. TiO2)

Massive ceramic

Concret fillingCast iron armour



Pump SealingSystems

CriticalComponents:-Spacer Can-Inner Rotor

Materials:-SX-Hastelloy C4-1.4539 (904L)

Horizontal Magnetic Driven Pumps

Inner rotor

Spacer can



Pump SealingSystems

&

UniqueMaterialSilicon CastIron (15% Si)

Hydrodynamic Shaft Seal

Hydrodynamic shaft sealwith up to 3 expellers

Standstill seal:grease, pneumatic, packing

Concretfilling

Silicon cast iron

Cast iron armour



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 technicalinformation 1

Siguss is resistant against corrosion of sulphuric acid at all concentrations and temperatures

Silicon CastIron(15% Silicon)

Corrosion Rate per Year



Pump SealingSystems

&

UniqueMaterialSilicon CastIron (15% Si)

Pumps in a Weak Acid Evaporation Plant



Ilmenit Ore is digested in sulphuric acidFinal Product: white TiO2 pigments

Sulfate Processindustrially since 1916

A Special Pumpfor a SpecialApplication

GermanHistory

Titanium Dioxide Production – Sulfate Process



Sulfate Processwithout spend acid regeneration

Sulfate Processwith spend acid regeneration

Chloride Process

Prohibition of Ocean Dumping

Development of Production Processes forTitanium Dioxide at Kronos Titan


GermanHistory

Titanium Dioxide Production – Sulfate Process




GermanHistory

Weak Acid Dumping at the North Sea




GermanHistory

Acid Circulating Pump with an “Inducer” Impeller

Hydrodynamic shaft sealwith up to 3 expellers

Pneumatic standstillseal

Concret filling

Silicon cast iron

Cast iron armour



30 - 80% H2SO4with metal sulfatechrystals

T: 50 - 190°CQ: 1500 m³/hH: 3 mDN 500


GermanHistory




30 - 80% H2SO4with metal sulfatechrystals

T: 50 - 190°CQ: 1500 m³/hH: 3 mDN 500


GermanHistory




New SealingSystemDevelopment

Cardridge seal

Gas Lubricated Shaft Seal for Hot Sulphuric Acid



Documents

Sulphuric Acid: A Challenge for Materials and Sealing ... Acid: A Challenge for Materials and Sealing Systems for Centrifugal Pumps AIChE Clearwater Convention 2010; Dr. Jürgen Weinerth