Design of Strong Acid System · 2013. 5. 30. · Alloy Acid Coolers –Advantages Low Maintenance Practically no maintenance, physical and chemical cleaning periodically. No need

Design of Strong Acid System:An Efficient, Safer, Cleaner and Economical System

Chile 15th Oct ’12

9th Roundtable of Sulphuric Acid Plants

Aditya Sheth

Galiakotwala Engineering Co.

India

Introduction by

Gonzalo Irarrazaval

Section 1Section 1Introduction to Galiakotwala Engineering Division

Galiakotwala Engineering Division

Galiakotwala Group was founded in 1923

� Galiakotwala Engineering Division manufactures strong acid circulation equipment

and mist elimination equipment for Sulphuric acid industry

� Galiakotwala Engineering Division is a part of the Galiakotwala Group of

Companies that also has an interest in

- Cotton Trading- Cotton Trading

- Paints Manufacturing

- Steel Barrel Manufacturing

- Real Estate Development

- Hardware and Electronics Marketing

� Galiakotwala Engineering Division was founded in 1985 and managed by

Mr. Mahendra Sheth (Managing Director) and 50 employee team

Directors Profile

Mr. Mahendra Sheth

Education:

Chemical Engineering (B.S and M.S.) - New Mexico University (U.S.A.)

Industrial Engineering (B.S) - New Mexico University (U.S.A.)

Work Experience :

Phelps Dodge Corporation (U.S.A.) - (1975-78)

MECS - (U.S.A.) (1978-84)MECS - (U.S.A.) (1978-84)

Galiakotwala Engineering Division (Founded 1985)

Mr. Aditya Sheth

Education:

Chemical Engineering (B.S.) - Columbia University (New York, U.S.A.)

Economics (B.A.) - Denison University (Ohio, U.S.A.)

Work Experience:

UBS Investment Bank (New York, U.S.A.) – Chemical Division (2006-2008)

Galiakotwala Engineering Division (2008 onwards)

Section 2Section 2Introduction to Sulphuric Acid Plants

Importance of Sulphuric Acid

� Manufacturing of Phosphate Fertilizer

� Hydrometallurgy(Copper, Nickel, Zinc, Lead)

� Lead – Acid Batteries

� Production of Titanium Dioxide

� Alkylation in Petrochemical plant

Sulphuric Acid is one of the most widely used chemical in the world.

� Dehydrating Agent(Chlorine Manufacturing)

� Metal Process (Pickling)

� Production of Rayon / Viscose Fibers

� Water Treatment Industry(PH Control)

� Manufacturing of Dyestuff

� Extraction of Uranium

� Electronic Industry

History Of Sulphuric Acid Plants

� Discovered in 10th Century by

Persian Alchemist

� Contact process patented by Philip

in 1831

� BASF commercializes contact

process in 1901process in 1901

Types of Acid Plants

Sulphur Burning

Elemental sulphur is a raw material.

S(Rhombic) + O2(g) -> SO2(g) EXOTHERMIC -297 kJ/mol

Acid Regeneration

There are mainly three types of Sulphuric acid plants:

Acid Regeneration

Decompose spent sulphuric acid into SO2 and H2O.

H2SO4-> SO2 + H2 O + 1/2O2 ENDOTHERMIC +202 kJ/mol

Metallurgical

SO2 gas comes from a wide variety of pyro metallurgical processes.

M(S) + O2 -> Metallic Fumes + SO2 EXOTHERMIC

Section 3Section 3Acid Circuit of Sulphuric Acid Plants

Typical Contact Section

Drawing for Illustration purpose only

Typical Conventional Acid Circuit


Equipments in Acid Circuit

� Acid Towers

� Acid Distributors

� Mist Eliminators

� Acid Pump Tanks

� Acid Piping

� Acid Coolers

Acid Circuit - Acid Towers


Conventional M.S.-Brick Lined Tower

� M.S. towers requires brick-rephanol lining

which significantly increase complexity

and installation time

� Heavy structural support and foundation

required

� Brick joints are extremely difficult to locate� Brick joints are extremely difficult to locate

and repair

� Reduce area for gas flow due to brick

arches that support packing. Gas flow not

uniform through cross section


Alloy Tower

� No brick lining, prefabricated

� Low weight, easy to install, light structural

support and foundation

� Long service life, usually 20+ yrs. Low

corrosion and iron content

� Reliable operation - Fully weldable, leaks� Reliable operation - Fully weldable, leaks

can be quickly located and repaired

� Alloy packing support ensures greater than

80% open area ensuring optimum gas

distribution through the packing distribution

� Higher drying and absorption efficiency with

alloy internals


Acid Circuit Upgrade - Acid Towers


Acid Circuit – Acid Distributors


Conventional Distributors - Cast Iron

� Several joints due to casting process

� Higher corrosion rate

� Orifice sizes become bigger,

changing distribution flow pattern in

tower

� Sulphate formation, plugging tower

and mist eliminators

� Heavy and bulky making it difficult to

handle and clean

� Stocking of spare parts is required as no

possibility of welding

Alloy Pipe Acid Distributors

Alloy Trough Acid Distributors

Higher Efficiency can be

achieved by trough

distributor albeit at a higher

cost

Alloy Acid Distributors - Advantages

� More Irrigation per unit area:

~ 2-4x more orifices points

� Uniform Distribution:

Distribution points will be evenly

spaced

� Unchanged Performance:

No change in orifice diameter in alloy

� No Solids Buildup:

Low corrosion rate there is no

iron sulphate formation and build up

in the tower

� Easy to Install and Maintain:

Due to light weight compared to cast

iron it is easy to install and maintainNo change in orifice diameter in alloy

distributors due to low corrosion

� Low Gas Pressure Drop:

Give gentle distribution, reduced

generation of acid mist

iron it is easy to install and maintain

� Minimum Downtime:

Maintenance free and therefore will

be no downtime

Acid DistributorsAcid Distributors after operations for ~8 yrs

Severe corrosion seen in cast iron distributors, in

some location pipes have broken

Alloy distributor is unaffected

Acid Circuit Upgrade – Alloy Acid Distributors


Acid Circuit – Mist Eliminators


Conventional Mist Eliminators –

PTFE/ETFE Mesh Pads

Mesh Pads in Hostaflon

Mist Eliminators – PTFE/ETFE Mesh Pads

Hostaflon mesh pads after 3 years of

service in Drying Tower of Sulphuric

Acid Plant

Shrinkage and Gaps

can be seen

Mist Elimination - Alloy Mesh Pads

� Mesh pads can be made from metallic

alloys such as SX and Alloy 20

� Long life due to low corrosion in Sulphuric

Acid. Lowest corrosion in SX

� No problems with shrinkage and melting

associated with fluoropolymers such as

Teflon and Hostaflon

� Efficiency can be increased by co-knitting

alloy demisters pads with fine PTFE fiber

or glass fiber

Mist Elimination - Alloy Mesh Pads

MESHPAD in SX after 15 years of continous

service in sulphuric acid (no washing)

No gaps can be seen, mesh pad

has no major damage

or loss of performance

Mist Eliminators - Brownian Type

1st Generation 2nd Generation 3rd Generation

� Fiber Donuts packed

between two cages

� Possibility of gas

bypass between two

donuts

� Fiber Mat wrapped

around cage

� Choking possibility and

low efficiency below 0.5

microns

� Loose fiber packed

between cages

� Solves problem of

gas bypass


� Rope type roving fiber

machine wrapped around

cage

� Dual layer technology with

dedicated drainage layer

Mist Eliminators - Impaction Type

3rd Generation1st Generation 2nd Generation

� Dual layer technology with fiber

layer acting as filtration layer and

co-knit layer for enhanced

drainage with longer cleaning cycles

� Fiber Mat or loose fiber

wrapped/packed

between cages

� No dedicated drainage layer

� Dual layer technology with

fiber layer acting

as filtration layer and metallic layer for enhanced drainage


Acid Circuit Upgrade – Mist Eliminators


Acid Circuit – Acid Pump Tank


Acid Pump Tanks

� Vertical pumps tanks with flat bottoms

have risk of brick lining of base coming

loose

� Dished bottom vertical and horizontal

brick lined tanks are under compression

reducing possibility of brick loosening

� Horizontal pumps tanks made from alloy

material are a further advancement inmaterial are a further advancement in

pump tanks where no brick lining is

required

� Size of horizontal pump tank can be

reduced as part of the acid can be stored

in tower

� U-seal can be avoided as liquid seal is

completed by leaving part of the acid in

the tower

Acid Circuit Upgrade – Alloy Horizontal Pump Tanks


Acid Circuit – Acid Piping


Conventional Acid Piping – Ductile or Cast Iron Piping

� Large number of flanges due to casting

limitations significantly increasing risk of

acid leaks

� Constant requirement of maintenance

and inventory of spares. No possibilities

of welding

� Difficult handling due to heavy weight

and bulk

� Low ductility in case of cast iron, higher

risk of brittle failure resulting in lower

safety

� High corrosion and erosion rate in case of

Cast Iron

� High Iron Sulphate formation (sludge)

plugging packing and mist eliminators

Acid Piping – Alloy Piping

Alloy Acid Piping - Advantages

� Longer Life:

Very low corrosion rate ~ 0.025m/yr

to 0.1mm/yr resulting in life of 15+ yrs

� Reliable and Safe Operation:

Welded construction significantly

reduces number of flanges and

minimizing possibility of acid leaks

� Easy Handling:

Easy erection and movement of alloy

pipes due to lightweight and compact

size

� No Possibility of Brittle Failure:Higher ductility and malleability,

minimized risk of brittle failureminimizing possibility of acid leaks

� No Solids Buildup:

No Iron Sulphate formation due to

negligible corrosion resulting in

reduced plugging and maintenance

of tower

� No Maintenance or Inventory:Practically zero maintenance and no

requirement for any spares.

Full possibility to weld and repair

on-site using conventional welding

techniques

minimized risk of brittle failure

resulting in higher safety levels

Acid Circuit Upgrade – Alloy Acid Piping


Acid Circuit – Acid Coolers


Conventional Acid Coolers

1st Generation – Trombone Cooler 2nd Generation – PHE

� CI pipes cooled by water showers

� High water loss and huge

generation of sludge

� Low reliability, safety of cooler is low

due frequent breakdowns

� Large requirements of spare parts

� Metallic plates are pressed with

acid/water flow direction and are

placed together with gaskets or semi-

welded

� Small clearance between plates,

mortar, bricks and other solid particles

can plug PHEs

Shell & Tube Type – 3rd Generation

Anodically protected coolers

� Corrosion rate of an active-passive metal

can be significantly reduced by shifting

the potential of the metal so that it is at a

value in the passive range

� Cooler MOC is generally SS 316L or SS

304L with electronics added for anodic

protection

Alloy Coolers

� No anodic protection, base material is

corrosion resistant

Shell & Tube Type

Heat Exchanger

Photo for Illustration purpose only

Alloy Shell & Tube Acid Coolers - 3rd Generation

Alloy Acid Coolers – Advantages

� Low Maintenance

Practically no maintenance, physical

and chemical cleaning periodically.

No need of changing expensive

gaskets or replacing electrical parts

� Leak Free Design

Fully welded construction withoutgaskets or joints

Safe and clean operating area, nopossibility of leakage in operatingarea

� Self Cleaning

Water side of the heat exchanger is cleaning when right quantity andcorrect composition of water ismaintained.

� Longer Life

Corrosion rate is very low

15+ years of life if operatedcorrectly

Alloy Acid Coolers – Advantages

Does not have sensitivity to higher

temperatures and higher velocities

No risk in counter current design

possible due to lower risk of elevated

tube wall temperatures unlike AP

� Thermally Optimal Design � Heat Recovery

Energy can be recovered from acid

circuit by heating process water

tube wall temperatures unlike AP

type coolers

An Efficient, Safer, Cleaner and Economical

Acid Circuit

Equipment Efficient Safer Cleaner Economical

Alloy Tower � Reduced

diameter

� Light weight

� Higher eff.

� Leaks can be

quickly

identified/fixed

� No Iron

Sulphate

sludge

formed

� No brick lining

� Quick installation

Alloy

Distributor

� More

irrigation pts

� Easier handling

due to light

� No Iron

Sulphate

� Longer life

� MinimumDistributor irrigation pts

� Uniform

distribution

� Unchanged

performance

due to light

weight

Sulphate

sludge

formed

� Minimum

downtime

Alloy Mesh

Pads

BMW and

IMW Candles

� Better eff

with lower

pressure

drop

� Re

-entrainment

control

� Less possibility

of mist bypass

reducing

equipment

failure or

environmental

damage

� Less

possibility

of mist

bypass

reducing

equipment

corrosion

� Longer life

� Reduces equip

damage

� Lower pressure

drop reducing

required power


Acid Circuit


Alloy

Horizontal

Pump Tank

� Not susceptible

to brick

loosening

� Smaller size

� No U-seal

� Reduces

piping

reducing

leaks

� Leaks

easily

� No

formation

of Iron

Sulphate

sludge

� Longer life

� Reduced piping

easily

identified

and fixed

Alloy Piping � Reduced piping

length and

diameter

� Higher velocities

and temperatures

can be used

� Practically zero

maintenance

required

� Significantly

less flange

joints

� Leaks can

be easily

fixed

� No

possibility of

brittle failure

� No

formation

of Iron

Sulphate

sludge

� Longer life

� Correct alloy

selection based

on process data

� No need to

maintain

inventory


Acid Circuit


Alloy

Vertical

Coolers

� Thermally

optimal, counter

current design

can be used

due to low

� Leak free

design,

fully welded

construction

� No changing

� No possibility

of any acid

outside

cooler, clean

operating

� Longer life

� Allows

vertical

installation

significantlydue to low

sensitivity to

temperature

and velocity

� No changing

of gaskets or

electrical

parts

operating

area

significantly

reducing

piping

Contact Information

Satisfied more than 150 Sulphuric Acid plantacross 27 years

Quality Comes First

Galiakotwala Engineering Division

Galiakotwala Group

66, Maker Chambers 3, Nariman Point

Mumbai-400021, India.

Tel: +91 02 2 22843758 | Fax: +91 022 22048801

www.galiakotwala.in

Documents

Design of Strong Acid System · 2013. 5. 30. · Alloy Acid Coolers –Advantages Low Maintenance Practically no maintenance, physical and chemical cleaning periodically. No need