Addressing formulating difficulties of high-temperature engineered coatings technologies

1. Advancements
in
Ceramic
Coating
Technology
for
the
Power
Generation
Industry
Aldrin
Arquillano
M.Eng,
Research
Associate
Furnace
Mineral
Products
Inc.
(FMP
Coatings)

2. Industrial processes are operating at higher temperatures and
the corrosion rates are accelerating
Conventional organic coatings are exhibiting limited success above
100 oC in immersion service
Next generation hybrid coatings are maximizing temperature resistance
These solvent free coatings can withstand temperatures above 200oC while
providing excellent erosion and chemical resistance

3. ØOperating
temperature
(wet/dry)
service
ØIntermittent
/
Upset
exposure
ØLevels
of
corrosive
liquids/gases
ØMicrobial
activity
(SRB)
ØCleaning
chemicals/steam
cleaning
ØRapid
decompression
ØCondensate
moisture
ØCost
of
failure

4. High sulphur fuel in the presence of moisture forms sulphuric acid
Acidic gas condenses out of the flue gas stream on cooling
Acid condenses at 115 – 160 oC resulting in aggressive corrosion
Coating have had limited success in this environment
The combination of erosion, high wet temperature and strong acidic
attack pushes the limits of organic coating technology

5. • Resistant
to
high
temperature
(265
oC
dry
– 200
oC
wet)
• High
wear
resistance
• Ambient
temperature
cure
• Environmentally
friendly,
zero
VOCs
• Chemical
resistant
(H2SO4,
HCl)
• Single
coat
high
build
application
• Spray
applied
• Rapid
return
to
service

6. ORGANIC
CHEMISTRY
Contains
backbones
comprised
of
chains
and/or
rings
of
carbon
(plant
based)
and
hydrogen
atoms.
INORGANIC
CHEMISTRY
Contains
backbones
comprised
of
non
carbon
containing
elements
such
as
silicon
(mineral
based).
Silicon
offers
extreme
thermal
stability
and
temperature
resistance

7. • Ceramic
inorganic
chemistry
for
combustion
service
ranging
from
370
to
800
oC
• Upon
curing
the
coating
forms
an
amorphous
layer
that
bonds
the
ceramic
matrix
to
the
substrate
surface
• Limitations
– requires
post
cure
at
elevated
temperature
– Not
suitable
for
immersion
service
– Difficult
to
apply
– Thin
film

8. Glass
Transition
Curve
Cross
Link
Density
Low
Tg Higher
Tg
Why
traditional
epoxies
fail
at
high
temperature
• Low
Tg
• Low
cross
link
density
• High
free
volume

9. • Epoxy
coatings
are
organic
thermosetting
polymers
• Cure
by
chemical
reaction
• Reaction
between
epoxide
resin
and
an
amine
curing
agent
• 3
main
components
to
epoxy
coatings
(resin,
hardener
and
modifier)
• Primary
indicator
of
temperature
resistance
is
Tg

10. Type Structure Viscosity Tg
Bisphenol A
15,000
cps 175 oC
Bisphenol F
5,000
cps 150 oC
Novolac
Semi Solid
at
Room
Temperature
200
oC

11. *Viscosity
of
water
is
1
cps
0
50
100
150
200
250
Bisphenol
F Bisphenol
A Novolac
Resin
Tg (oC)
0
10
20
30
40
50
60
70
80
90
Bisphenol
A Bisphenol
F Novolac
3.6
f
Temperature
at
4,000
cps
0
10
20
30
40
50
60
Bisphenol
A Bisphenol
F Novolac
3.6
f
Percentage
%
Diluent
Requirement
to
Drop
to
4,000
cps

12. • Types
of
Epoxy
Curatives
• Polyamide
• Aliphatic
• Cycloaliphatic
• Aromatic
0
50
100
150
200
250
Amide Aliphatic Cycloaliphatic Aromatic
Temperature
oC
Hardener
Curing
Temperature

13. • Hybridized
• Incorporate
silicon
bonding
• High
functionality
novolac epoxy
• Ceramic
fillers
• Cycloaliphatic amine
or
aromatic
amine

14. • Include
rubber,
ceramics,
pigment,
solvent,
fillers,
flame
retardants,
and
diluents
• Use
of
solvent
or
non
reactive
diluents
must
be
avoided
(xylene,
benzyl
alcohol)
• Reactive
diluent
avoided
or
only
low
levels
• Fillers
must
be
thermally
stable
at
higher
temperature

15. • Solvency
– viscosity
reduction
• Environmental
impact
• Sacrifice
performance
• Will
not
survive
high
temperature
exposure
Autoclave
Testing
96
hrs at
120
oC
at
vapour
pressure

16. • A
100%
solids
coating
system
is
defined
as
a
coating
that
results
in
no
film
thickness
change
during
application.
• So
how
does
a
formulator
of
100%
solids
coating
drive
down
the
viscosity
so
that
the
coating
can
be
sprayed
or
rolled
?
• The
trick
is
the
use
of
a
high
boiling
point
solvent
(ie,
benzyl
alcohol)
that
is
volatile
but
also
reacts
with
the
epoxide
group
of
the
coating
so
that
the
bulk
of
the
solvent
remains
in
the
coating
system.
• In
high
temperature
systems
this
approach
DOES
NOT
work
• To
overcome
the
need
for
solvent
or
diluent,
the
system
must
be
heated
to
reduce
viscosity

17. • Two
methods
• Single
leg
hot
pot
• Plural
component
spray
Characteristic Single Leg
(heated) Plural
Component
(heated)
Ease
of
Application Requires skilled
technician Requires skilled
technician
Cost
of
Equipment $7,000
USD $30,000
-­‐ 50,
000
USD
Solvent
consumption Flush every
30
min
(dependant
of
the
pot
life
and
exotherm)
Flush
at
the
end
of spray
Pot
Life Min
30 min No
limit
Max
Material
Viscosity 20,000 cps 80,000
cps
Max Temperature 38
oC 65 oC

19. Lower intercoat porosity
Single coat application reduces the
risk of intercoat failure
Improved edge retention
> 75 %
Improved pit coverage
Improved adhesive strength

20. Test
Method Description
ASTM
D648 Heat
Deflection Temperature
ASTM
D6137 Sulfuric Acid
Resistance of
Polymer
Linings
for
Flue
Gas
Desulfurization
Systems
ASTM
D5499 Heat
Resistance
of
Polymer Linings
for
Flue
Gas
Desulfurization
Systems
NACE
TM
0174 Laboratory
Methods
for
the
Evaluation
of
Protective
Coatings
and
Lining
Materials
on
Metallic
Substrates
in
Immersion
Service
NACE
TM
0185 Evaluation
of
Internal
Plastic
Coatings
for
Corrosion
Control
of
Tubular
Goods
by
Autoclave
Testing
ASTM
2485 Evaluating
Coating
for
High
Temperature Service
CSA
Z245.20 Hot Water
Soak
Test

22. • Use
more
aggressive
wheel
– H 18
(1
Kg,
1000
cycles)
• Result
must
be
less
than
100mg
to
survive
high
erosive
flue
gas
rates

23. • Modified version of ASTM G76
• 60 m/s aluminum oxide at a 30 mm stand off
• Evaluate both 90o and 30o angles

24. Atlas
Cell
Testing
Poor
wet
adhesion
Blisters
at
thin
coating
Hybrid
Material

25. Testing Result
Auotclave at
96 hrs at
160
oC Pass
Taber
Abrasion
CS-­‐18, 1kg,
1000
cycles
<
50
mg
Mix
Ratio 4:1
(resin:hardener)
Holiday
detectable Yes
Chemical
resistance Pass
H2SO4, HCl,
CH2Cl2 (168
hrs)
Autoclave
at
96
hrs
at
160
oC

26. • Hybridization
is
at
the
forefront
for
advanced
high
temperature
development
work
• Test
methods
must
best
simulate
the
service
environment
• Heated
plural
component
spray
adds
performance
benefit
• Proper
high
temperature
formulations
will
drive
longer
term
performance

27. www.fmpcoatings.com
aldrin@fmpcoatings.com