performance of an entegris phasor x heat exchanger in cabot semi...
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CTA pub #75.pptSlide 1
Performance of an Entegris pHasor® X Heat Exchanger in Cabot Semi-Sperse® 12
Mark Litchy, Dennis Chilcote and Don GrantCT Associates, Inc.
Bipin Parekh, Annie Xia, Michael Clarke, and Russ MollicaEntegris, Inc.
2008 CMP Users ConferenceFebruary 12, 2008
CTA pub #75.pptSlide 2
Introduction
• Heat exchangers can be used to efficiently remove heat from liquid delivery systems, such as those incorporating centrifugal pumps.
• The heat exchanger evaluated is constructed entirely of PFA to provide– High purity– Chemical compatibility
• Even though it is constructed of PFA, it is efficient at removing heat with an acceptable pressure drop.
• However, in slurry applications, there is concern that the heat exchanger may damage the slurry or clog.
CTA pub #75.pptSlide 3
Introduction
• Materials of construction and design are important:– Thermal conductivity– Corrosion resistance– Capable of withstanding thermal stresses and high pressures
• Since PFA has poor thermal conductivity properties relative to most metallic heat exchangers– Tube thickness must be thin– Exchanger must be well designed to prevent flow channeling and
streaming– Surface area must be large
• Tradeoffs:– Reducing the tube thickness reduces the operating temperature and
pressure rating of the device– Increasing the surface area increases cost and size of the device
CTA pub #75.pptSlide 5
Experiments performed in water
• Measurement of pressure drop (∆ P) in the tube and shell as a function of flow rate.– PHX03U (U configuration, short: surface area = 0.3 m2)– PHX08S (S configuration, long: surface area = 0.8 m2)– PHX08U (U configuration, long: surface area = 0.8 m2)
• Measurement of heat transfer coefficients at a series of flow rates for 3 different heat exchangers.– PHX03U– PHX08S– PHX08U
CTA pub #75.pptSlide 6
Schematic of pressure drop versus flow rate test system
circulationpumpwater tank
T
heat exchanger
flow controlvalve
FM
P
∆P
flowmeter
thermistor
differentialpressure gauge
CTA pub #75.pptSlide 7
Schematic of heat transfer coefficient test system
circulationpumpwarm
water tank
to drain
cold water supply
T1
T3
T4
heat exchanger
FM
T2
flow controlvalve
to mainwater loop
flow controlvalve
regulator
FM
inletfilter
FM
T1
flow meter
thermistor #1
CTA pub #75.pptSlide 8
Calculation of heat transfer coefficient
• where:– U = heat transfer coefficient (Btu/hr/ft2/°F)– Q = flow rate on the tube side (lb/hr)– c = specific heat of water (Btu/lb/°F) = 1.0– ∆Ttube = Ttube in- Ttube out (°F)– A = surface area of heat exchanger (ft2)– ∆Tln = logarithmic mean temperature difference =
[∆T0 – ∆TL]/[ln(∆T0/∆TL)] • where: ∆T0 and ∆TL= temperature differences between the hot
and cold fluids at the two ends of the heat exchanger, x = 0 andx = L
ln
tube
TA T c QU
∆
∆=
CTA pub #75.pptSlide 9
Experiments performed in slurry
• Measurement of the effect of the heat exchanger on the slurry particle size distribution (PSD) of Cabot Semi-Sperse® 12 (SS-12).– PHX08U (U-line long)
• 38.5 lpm• 10 lpm
– Stainless steel coil (control test)• 38.5 lpm
CTA pub #75.pptSlide 10
Slurry test system schematic
BPS4
T2
T4T5
Heat Exchanger
Chiller
flow meter
∆P
flow meter
SS12
Humidified N2
T3
T1
CTA pub #75.pptSlide 11
Details of tests performed in slurry
• Tests at 38.5 lpm (PHX08U and control test):– Test system volume: 50L of SS-12– Duration: 5 days (or ~5,700 turnovers)– Pump outlet pressure: 34 psig
• Test at 10 lpm (PHX08U test only):– Test system volume: 29L of SS-12– Duration: 10 days (or ~5,700 turnovers)– Pump outlet pressure: 3 psig
• All tests:– Tank blanketed with humidified N2: RH > 90%– Slurry temperature: 21 ± 1°C– SS-25 was filtered using an Entegris Planargard CMP5 10” filter prior to the
test– SS-25 was then diluted with ultra pure water as it was added to the test
system tank.
CTA pub #75.pptSlide 12
Particle size measurement
• “Working” particle size distribution– Measured using dynamic light scattering– Instrument used – NICOMP 380ZLS (Particle Sizing Systems)– All particles in a defined volume illuminated simultaneously– Particles are sized by measuring their diffusion coefficient– Measures relative concentrations– Sensitive to about 1% by volume
• “Large particle tail” size distribution– Instrument used:
• AccuSizer 780 sensor (Particle Sizing Systems)– Uses a combination of light scattering and light extinction to size
particles ≥ 0.56µm– Requires dilution
• CMP Slurries contain >1014 working particles/ml• The large particle tail contains ~106 particles/ml (≥ 0.56µm)
CTA pub #75.pptSlide 13
Working particle size distributions (PSDs)
Particle Diameter (µm)
0.02 0.03 0.04 0.06 0.08 0.2 0.3 0.4 0.6 0.80.01 0.1 1Rel
ativ
e V
olum
e-W
eigh
ted
Diff
eren
tial C
once
ntra
tion
(%)
0
5
10
15
20
25
CTA pub #75.pptSlide 14
AccuSizer dilution system schematic
CirculationPumpUltrapure Water
Tank
Static Mixer
Drain
PIAccuSizer
Sensor
SlurrySample
FilterInjection Pump
Bypass Loop
CTA pub #75.pptSlide 16
Comparison of ∆ P vs. flow rate: shell side
Flow rate (lpm)
0 5 10 15 20 25
Diff
eren
tial P
ress
ure
Acr
oss
Hea
t Exc
hang
er (p
sid)
0
1
2
3
Diff
eren
tial P
ress
ure
Acr
oss
Hea
t Exc
hang
er (k
Pa)
0
5
10
15
20PHX03U-shellPHX08U-shellPHX08S-shell
CTA pub #75.pptSlide 17
Comparison of ∆ P vs. flow rate: tube side
Flow rate (lpm)
0 5 10 15 20 25
Diff
eren
tial P
ress
ure
Acr
oss
Hea
t Exc
hang
er (p
sid)
0
1
2
3
Diff
eren
tial P
ress
ure
Acr
oss
Hea
t Exc
hang
er (k
Pa)
0
5
10
15
20PHX03U-tubePHX08U-tubePHX08S-tube
CTA pub #75.pptSlide 18
Summary of differential pressure results
• Differential pressure drop versus flow rate were similar for both the PHX08U and PHX08S configurations.
• The ∆ P across tubes for the PHX03U configuration was significantly lower.
CTA pub #75.pptSlide 19
Heat transfer coefficients vs. flow rate: PHX03U
Flow Rate (lpm)
0 5 10 15 20 25
Hea
t Tra
nsfe
r Coe
ffic
ient
(Btu
/hr/f
t2 /F)
50
75
100
125
150
175
200
Hea
t Tra
nsfe
r Coe
ffic
ient
(W/m
2 /K)
400
600
800
1000Vary tube flow rate, constant shell flow rate = 12 lpmVary shell flow rate, constant tube flow rate = 12 lpm
CTA pub #75.pptSlide 20
Heat transfer coefficients vs. flow rate: PHX08U
Flow Rate (lpm)
0 5 10 15 20 25
Hea
t Tra
nsfe
r Coe
ffic
ient
(Btu
/hr/f
t2 /F)
50
75
100
125
150
175
200
Hea
t Tra
nsfe
r Coe
ffic
ient
(W/m
2 /K)
400
600
800
1000Vary tube flow rate, constant shell flow rate = 12 lpmVary shell flow rate, constant tube flow rate = 12 lpm
CTA pub #75.pptSlide 21
Heat transfer coefficients vs. flow rate: PHX08S
Flow Rate (lpm)
0 5 10 15 20 25
Hea
t Tra
nsfe
r Coe
ffic
ient
(Btu
/hr/f
t2 /F)
50
75
100
125
150
175
200
Hea
t Tra
nsfe
r Coe
ffic
ient
(W/m
2 /K)
400
600
800
1000Vary tube flow rate, constant shell flow rate = 12 lpmVary shell flow rate, constant tube flow rate = 12 lpm
CTA pub #75.pptSlide 22
Summary of heat transfer coefficient results
• The S configuration is slightly more efficient than the U configuration.
• The long heat exchangers were more efficient than the short heat exchanger.
• Approach temperatures for these tests were ~10°F, which is a reasonable operating condition.
• Typical heat transfer coefficients in shell and tube heat exchangers ~30-300 Btu/hr/ft2/°F
Average Heat Transfer Coefficients (Btu/hr/ft2/°F) Configuration PHX08S PHX08U PHX03U
Average of 4 heating and cooling tests 134 124 110
Std. dev. 2.6 2.8 12.1
CTA pub #75.pptSlide 23
Cumulative PSDs of the large particle tailControl Test (38.5 lpm)
Particle Diameter (µm)1 10
Cum
ulat
ive
Con
cent
ratio
n (#
/ml)
103
104
105
106
01130105319101214522256367447755694
pHasor X Test (38.5 lpm)
Particle Diameter (µm)1 10
Cum
ulat
ive
Con
cent
ratio
n (#
/ml)
103
104
105
106
01029973189891410236534225704
pHasor X Test (10 lpm)
Particle Diameter (µm)1 10
Cum
ulat
ive
Con
cent
ratio
n (#
/ml)
103
104
105
106
0103299509114515882526355652315709
Turnovers
Turnovers
Turnovers
CTA pub #75.pptSlide 24
Concentrations relative to initial concentration
> 0.56 µm> 0.7 µm> 1.0 µm> 2.0 µm> 3.0 µm
pHasor X Test (10 lpm)
Turnovers10 100 1000 10000
Con
cent
ratio
n R
elat
ive
to In
itial
Con
cent
ratio
n
0.1
1.0
10.0
Control Test (38.5 lpm)
Turnovers10 100 1000 10000
Con
cent
ratio
n R
elat
ive
to In
itial
Con
cent
ratio
n
0.1
1.0
10.0
> 0.56 µm> 0.7 µm> 1.0 µm> 2.0 µm> 3.0 µm
pHasor X Test (38.5 lpm)
Turnovers10 100 1000 10000
Con
cent
ratio
n R
elat
ive
to In
itial
Con
cent
ratio
n
0.1
1.0
10.0
CTA pub #75.pptSlide 25
Change in concentrations for selected sizespHasor X Test (10 lpm)
Turnovers
0 1000 2000 3000 4000 5000 6000
Cha
nge
in C
once
ntra
tion
(#/m
l)
-10000
-5000
0
5000
10000
15000
20000
Control Test (38.5 lpm)
Turnovers
0 1000 2000 3000 4000 5000 6000
Cha
nge
in C
once
ntra
tion
(#/m
l)
-10000
-5000
0
5000
10000
15000
20000
> 1.0 µm> 2.0 µm> 3.0 µm
pHasor X Test (38.5 lpm)
Turnovers
0 1000 2000 3000 4000 5000 6000
Cha
nge
in C
once
ntra
tion
(#/m
l)
-10000
-5000
0
5000
10000
15000
20000
CTA pub #75.pptSlide 26
Discussion of large particle test results
• A slight decrease in the large particle tail was observed duringthe control test.
• An increase in the concentrations of particles ≥ 1 µm was observed during the heat exchanger test at the higher flow rate.
• Agglomeration at smaller sizes probably occurred as well, but since the concentration of these particles was higher, no increase was apparent.
• Particle concentrations tended to increase roughly linearly withincreasing turnovers.
CTA pub #75.pptSlide 27
Discussion of large particle test results
• For particles ≥ 2 µm, the concentration increased by roughly a factor of 5 by the end of the test. This equates to a 0.07% increase in particle concentration ≥ 2 µm per pass through the heat exchanger. In a typical slurry delivery system application, slurry is used with ~100 turnovers, thus only a fairly small increase, ~7%, in concentration would occur.
• This level of increase is dramatically lower than generated by some pumps. (Previous studies have shown up to a 500% increase particle concentrations within 100 turnovers.)
Diaphragm Pump
Turnovers
1 10 100 1000 10000
Con
cent
ratio
n R
elat
ive
to In
itial
Con
cent
ratio
n
0.1
1.0
10.0
100.0
> 0.56 µm> 0.7 µm> 1.0 µm> 1.5 µm> 2.0 µm> 5.0 µm
2007 CMP Users Conference
CTA pub #75.pptSlide 28
Working particle size measurementsControl Test (38.5 lpm)
Turnovers
1 10 100 1000 10000
Vol
ume-
Wei
ghte
d D
iam
eter
(nm
)
0
50
100
150
200
250
300
350
Mean99th Percentile Size
pHasor X Test (38.5 lpm)
Turnovers1 10 100 1000 10000
Vol
ume-
Wei
ghte
d D
iam
eter
(nm
)
0
50
100
150
200
250
300
350
Mean99th Percentile Size
pHasor X Test (10 lpm)
Turnovers
1 10 100 1000 10000
Vol
ume-
Wei
ghte
d D
iam
eter
(nm
)
0
50
100
150
200
250
300
350
Mean99th Percentile SizeError bars represent ± 3σ
Error bars represent ± 3σ
Error bars represent ± 3σ
CTA pub #75.pptSlide 29
Discussion of working particle results
• No significant change in the mean or 99th percentile size was observed due to the presence of the heat exchanger.
• A small increase (25-35 nm) in the 99th percentile size was observed during the test at the high flow rate. However, this increase was also observed during the control test, thus it may be attributed to the test system rather than the heat exchanger.
CTA pub #75.pptSlide 30
Summary of slurry test results
• No indication of clogging or settling of slurry in the heat exchanger during these tests.
• The heat exchanger was capable of efficiently removing heat so that a constant temperature could be maintained.
• No significant change in the mean or 99th percentile size was observed due to the presence of the heat exchanger.
• Minimal change in the large particle tail was observed during the control test and heat exchanger test at 10 lpm.
• During the heat exchanger test at higher flow, an increase in particle concentrations were observed for particles ≥ 1 µm in size.
• Since slurry is typically used within 100 turnovers in a typicaldelivery system, only a small (~7%) increase in particle concentrations ≥ 2 µm would occur.
• This level of increase, although significant, is dramatically lower than that generated by some pump systems.
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