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
Drawing for Illustration purpose only
Equipments in Acid Circuit
� Acid Towers
� Acid Distributors
� Mist Eliminators
� Acid Pump Tanks
� Acid Piping
� Acid Coolers
Acid Circuit - Acid Towers
Drawing for Illustration purpose only
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
Drawing for Illustration purpose only
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
Drawing for Illustration purpose only
Acid Circuit Upgrade - Acid Towers
Drawing for Illustration purpose only
Acid Circuit – Acid Distributors
Drawing for Illustration purpose only
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
Drawing for Illustration purpose only
Acid Circuit – Mist Eliminators
Drawing for Illustration purpose only
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
Drawing for Illustration purpose only
� 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
Drawing for Illustration purpose only
Acid Circuit Upgrade – Mist Eliminators
Drawing for Illustration purpose only
Acid Circuit – Acid Pump Tank
Drawing for Illustration purpose only
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
Drawing for Illustration purpose only
Acid Circuit – Acid Piping
Drawing for Illustration purpose only
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
Drawing for Illustration purpose only
Acid Circuit – Acid Coolers
Drawing for Illustration purpose only
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
An Efficient, Safer, Cleaner and Economical
Acid Circuit
Equipment Efficient Safer Cleaner Economical
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
An Efficient, Safer, Cleaner and Economical
Acid Circuit
Equipment Efficient Safer Cleaner Economical
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