Transcript Fluorinated solvents

F-solvents
What do you expect from a new cleaning technology?
 Cleaning
/ Drying Performance
 Material Compatibility
 Safety-in-use (toxicological profile, flammability, stability)
 Environmental Impact
 Sustainability (regulatory issues)
 Cost of Ownership
(long-term strategy vs. short-term thinking)
F-solvents are a balanced combination of properties related to performance,
material compatibility, safety, environmental issues, and costs.
F-solvents
Purpose of F-solvents
 F-solvents
are designed to replace ozone-depleting
solvents such as:



CFC-113 (Freon®)
HCFC-141b
HCFC-225
 F-solvents
are also an ideal replacement for 1.1.1-TCA,
Trichlorethylene (TCE) and Perchlorethylene
 F-solvents may also replace aqueous-, alcohol-, nPropyl Bromide- and hydrocarbon-based cleaning
systems
F-solvents
Key characteristics of F-solvents (1)
 Zero
Ozone Depletion Potential (ODP)
 Very low Global Warming Potential (GWP), due to lower
atmospheric lifetime and mainly uses in blends
 Non-flammable, no flashpoint, no auto-ignition (except HFC-365)
 Excellent toxicity profile
 Good boiling point and low surface tension
 Low viscosity
 High liquid density
F-solvents
Key characteristics of F-solvents (2)
 Excellent
thermal, chemical and hydrolytic stability
 High material compatibility
 Excellent dielectric properties
 Easily miscible with numerous common solvents
 Recyclability of azeotropic mixtures
 Low energy consuming process, thus cost efficiency
 Can be used in combination with low volatility solvating
agents (such as Hydrocarbons)
F-solvents
Comparison of F-solvents vs. CFC-113 and HCFC141b
Safety and Toxicity related Properties
Property / Unit
HFC 43-10mee
Flash Point °C
none
Flammable range % vol
AEL 8-hr weighted average ppm
1HFC
HFC-365mfc
HFE-449s1
CFC-113
HCFC-141b
- 221
none
none
none
none
3.5 –9.0
none
none
5.6 – 17.7
200
500
750
1000
400
365mfc is not used as a pure fluid for precision cleaning, it is mixed to others F-solvents to
inert its flammability
F-solvents
Comparison of F-solvents vs. CFC-113 and HCFC141b
Environmental Properties
Property / Unit
HFC 43-10mee
HFC-365mfc
HFE-449s1
CFC-113
HCFC-141b
Atmospheric lifetime yr
17
10
4
85
9
Ozone depletion potential
0.0
0.0
0.0
0.8
0.11
Global warming potential
100 years IHT
1300
700
300
5000
700
Solubility in water
ppm
140
170
2700
Solubility of water
ppm
490
90
320
F-solvents
F-solvents
 Due
to solvent properties and optimized equipment
design, F-solvents emissions are 6 to 9 times lower
than CFC-113 and HCFC-141b emissions in identical
applications!
 Consumption data (given as an indication):


in idle conditions:
in real operation conditions:



10-20 g/m2.h
40-60 g/m2.h
72-hour test with cooling system always turned on (closed top 16 hours)
heating system turned on 8 hours / day with open top during operation
cleaning of screws in a 10kg basket with a cycle time of 6 minutes
F-solvents - Equipment Design
Key Equipment Enhancements for Open Top Systems
 Increased
Freeboard height (recommended ratio = 1.8)
 Optimized cooling coil system (DuPont’s Triple Guard®)
 Robot vs. manual handling (maximum vertical speed =
0.01 m/s, and maximum horizontal speed = 0.03 m/s).
 Sliding lid, to avoid any piston effect
 Superheating chamber (10-15 ºC above boiling point)
Optimized equipment design impacts the solvent consumption,
NOT the cleaning and drying performance!
F-3
F-solvents - Equipment Design
Reference consumption data (indication)
With a higher freeboard and improved cooling system:

Machine (idle) with heat on & cooling system on (open top)
< 15 g / m2.h

Machine (idle) with heat off & cooling system on (closed top)
< 10 g / m2.h

Machine (work) with heat on & cooling system on (open top)
50 - 130 g / m2.h
40 - 80 g / m2.h (with robot)
20 - 60 g / m2.h (with robot & sliding lid)
F-solvents - Equipment Design
Recommended freeboard and cooling system design
L
l
Dehumidifier Coils
(3 to 6º C)


h2
H
Diffusion Control Coils
(-20 to -30 °C)

h1
Condensing Coils
(3 to 6 °C)

l
H = 1,5 L mini.
h1 = L
h2 = 0,5 L
Simpler (thus less expensive) design than the
original Triple Guard® System
Lower position of the dehumidifier coils and higher
temperature lead to reduced turbulence, thus
lower solvent losses
Deflectors break the convection movement
generated by the low temperature of the diffusion
control coils
Dehumidifier coils restrain the entry of air
moisture, thus the rapid freezing of the diffusion
control coils
F-solvents - Equipment Design
The equipment alternatives
 Open
Top machines
 Hermetic machines
 “Hybrid” solutions (pseudo-closed machines)
Choice depends on:




regulatory constraints
company internal policy (ISO 14000 certification)
characteristics of the cleaning process (type, number and
specificity of the parts)
batch or in-line production mode
F-1
Vertrel® - Equipment Design
Comparison of equipment types
+
Open Top
Hermetic
easy process integration
minimized floor space
lower capital investment
almost no solvent losses
eco-efficiency
long-term cost of ownership
Hybrid
THE
COMPROMISE
higher solvent consumption
atmospheric emissions
short-term cost of ownership
batch mode only
more floor space needed
high capital investment
F-2
F-solvents vs.
other cleaning agents
Aqueous systems
 Potential
corrosion of metal parts
 Low rinsing quality
 Separate drying step needed, lower drying quality
 Longer cycle time
 Energy intense
 High capital investment for the equipment
 Disposal & recycling possibilities of contaminated water
 Water availability & price in some regions
F-solvents vs.
other cleaning agents
Chlorinated & bromine-containing solvents
 Toxicity
 Material
compatibility
 Ozone depletion
 Flashpoint controversy
 Odor
 Presence of stabilizers (Need of periodical monitoring to avoid
hydrolysis (acidification) of the solvent)
 Difficult
process monitoring
 Need to use expensive equipments
F-solvents vs.
other cleaning agents
Alcohols and hydrocarbons
 Flammability
of alcohols
 Poor rinsing quality with hydrocarbons (no vapor zone)
 Difficult drying with hydrocarbons
(higher BP, thus higher drying temperature needed)