Fluid and Heat Transfer in a pilot plant. PEX exposure experiment. Testing of Exposed PEX.

3. PIPING CORP.
RAD TECH
Ryan Lee
Chief Engineer
Aimmaz Hasnain
Data Manager
Darika Bhatia
Project Engineer
Pilot Plant 15

4. Overview of the Project
Week 2-3 Pilot Plant Modification

5. Plant Modification
Original Plant (Week1) Modified Plant (Week5)
ASTM F2023-15
HX

6. Overview of the Project
Week 2-3 Pilot Plant Modification
Week 3-5 Fluid Mechanics Studies
Week 5-8 Heat Transfer Studies

7. Fluid Mechanics & Heat Transfer

8. Fluid Mechanics & Heat Transfer
0.5” x 12’ HX

9. Overview of the Project
Week 2-3 Pilot Plant Modification
Week 3-5 Fluid Mechanics Studies
Week 5-8 Heat Transfer Studies
Week 9-13 PEX Oxidation Studies

10. Table of Contents
1. Modified ASTM F2023 testing on PEX specimens
2. PEX exposure experiment
3. Analysis of exposed PEX
- Visual Assessment
- Infrared Spectrometry
- Tensile Test
4. Conclusions and Recommendations

11. Overview of Exposure Conditions
Purpose: To examine the oxidative degradation of plastic piping (PEX) used
in potable water by exposing it to the free chlorine environment
Experiment:
1. Exposure of the test specimens to oxidative environment
2. Examination of exposed specimens

12. Overview of Exposure Conditions
There are the parameters that must be controlled during the exposure of the
specimen to the oxidative environment over 1 hour period!!
1. Total Chlorine concentration
o Circulating in system: 4.2 ± 0.2 ppm
o In feed: 20 ppm
2. pH: 7.0 ± 0.1
3. Temperature: 30 ± 1 °C
4. Pressure: Estimate at PEX specimen entrance
5. Flowrate: Rotameter at the best flowrate to control temperature: 12 LPM

13. Instrument involved in maintaining test conditions
Pressure gauge:
- PEX entrance pressure every 3 minutes
Temperature Monitoring:
pH Monitoring: Sampling location
Free Chlorine Conc.: Sampling location
Rotameter:
- Flowrate monitoring every 3 minutes

14. Instrument Involved in Maintaining Test Conditions
Temperature Probe:
- Monitoring Temperature in
circulating tank every
3 minutes
pH Meter:
- Monitoring pH in circulating
Tank every 12 minutes
Spectrophotometer:
- Monitoring free chlorine
concentration every 12 minutes

15. Methodology for Detection of Free Chlorine
1. Determine the “Absorption Spectrum” of DPD-Free Chlorine Complex
:To obtain the wavelength at high absorbance (525 nm)
2. Prepare standard chlorines at various concentration and generate “Calibration
Curve for Free Chlorine”
:To obtain working range of free chlorine concentration (Quadratic Equation)
3. Analysis of Process Water Free Chlorine Concentration
:Utilize the Calibration Curve to monitor the free chlorine concentration
during PEX oxidation experiment
To monitor the presence/ concentration of free chlorine the reagent DPD is used
to produce a magenta color in aqueous solution as it forms DPD-Free Chlorine
Complex

16. Methodology for Detection of Free Chlorine
Absorption Spectrum
0.0000
0.0200
0.0400
0.0600
0.0800
0.1000
0.1200
0.1400
400 425 450 475 500 525 550 575 600
Absorbance
Wavelength (nm)
Absorption Spectrum of free chlorine between
400 nm and 600 nm
0.000
0.050
0.100
0.150
0.200
0.250
0.300
500 505 510 515 520 525 530 535Absorbance
Wavelength (nm)
Absorption Spectrum of free chlorine
between 500 nm and 535 nm

17. Methodology for Detection of Free Chlorine
Calibration Curve
y = 0.0122x2 - 0.0105x
R² = 0.999
0.000
0.100
0.200
0.300
0.400
0.500
0.600
0.700
0.800
0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0
Absorbance
Free Chlorine Concentration (ppm)
Calibration Curve of Free Chlorine between 0.0 ppm and
10.0 ppm measured at 525 nm

18. PEX Exposure Experiment
Mass and Energy
Balance:Mass Balance: Energy Balance:
Control Strategy: ‘On/Off’
System System 𝑄 𝐿𝑜𝑠𝑠 𝑖𝑛 𝑟𝑒−𝑐𝑖𝑟𝑐𝑢𝑙𝑎𝑡𝑖𝑜𝑛
𝑄 𝐶𝑜𝑛𝑡𝑟𝑜𝑙𝑙𝑒𝑑 𝐼𝑛𝑝𝑢𝑡𝑚 𝐶𝑜𝑛𝑡𝑟𝑜𝑙𝑙𝑒𝑑 𝐼𝑛𝑝𝑢𝑡 𝑚 𝑃𝑟𝑜𝑑𝑢𝑐𝑡 𝑃𝑢𝑚𝑝 𝑂𝑢𝑡𝑝𝑢𝑡
20.66 W 20.66 W186 ug/min134 ug/min 134.0 ug/min
PLC
ON Time: 36 sec per 1 count ON Time: 33 sec per 15 counts
Purpose: To perform PEX oxidation by controlling exposure conditions and keeping a
steady state system.
𝑚 𝐹𝑒𝑒𝑑 𝑃𝑢𝑚𝑝 𝐼𝑛𝑝𝑢𝑡 𝐼𝑛𝑝𝑢𝑡 𝑄 𝐻𝑒𝑎𝑡𝑖𝑛𝑔 𝑇𝑎𝑝𝑒 𝑃𝑜𝑤𝑒𝑟
465.71 W
Unbalance EnergyUnbalanced Mass
Balanced EnergyBalanced Mass

19. PEX Exposure Experiment
Control of Exposure Conditions
28.5
29
29.5
30
30.5
31
31.5
0 10 20 30 40 50 60 70
Temperature(Celsius)
Time (minutes)
Chlorine Water-Temperature Control Chart
Upper Control Limit
Lower Control Limit
Setp
oint
Increasing and Decreasing
In Control
0
0.05
0.1
0.15
0.2
0.25
0.3
0 20 40 60 80
Pressure(Bar)
Time (minutes)
Chlorine Water-Pressure Chart

20. PEX Exposure Experiment
Control of Exposure Conditions
6
6.2
6.4
6.6
6.8
7
7.2
7.4
7.6
0 10 20 30 40 50 60 70
pH
Time (minutes)
Chlorine water-pH Control Chart
Out of Control
2.50
3.00
3.50
4.00
4.50
5.00
0 10 20 30 40 50 60
Concentration(ppm)
Time (minutes)
Chlorine Water-Concentration Control Chart
A
B
C
D
E
F
Out of Control
Setpoint
Lower Control Limit
Upper Control Limit
Setpoint
Lower Control Limit
Upper Control Limit

21. Visual Assessment
Purpose: To observe any visible oxidation features of the exposed PEX pipes’ inner surfaces
Sample Preparation:
R L U
Cut 1” of each specimen off
Cut it in half along its axis
Bend-back
Using pliers and hand
Cut 8” of each PEX

22. Visual Assessment
Examine the Surface:
1. By eye
Right exposedLeft exposed Unexposed

23. Visual Assessment
2. ProScope HR
Right exposedLeft exposed Unexposed

24. Visual Assessment
3. Microscope
Magnification 100 XRight exposedLeft exposed Unexposed
Microcracks

25. Visual Assessment
Conclusion:
PEX Specimens Cracks / Crazing Hazing White layer
Exposed Left Microcracks N/A N/A
Exposed Right N/A N/A N/A
Unexposed N/A N/A N/A
There was no significant difference between specimens
PEX tubings were possibly not oxidized during the experiment
High performance instrument may be required (e.g. SEM - Scanning Electron Microscope)

26. Infrared Spectrophometry: FTIR
Purpose: Estimate the carbonyl index (CI) of chlorine-exposed PEX specimen
which may have undergone oxidative degradation by compared to the CI of an
unexposed PEX specimen
Test Method:
o Determined the IR spectrum of the specimens using ATR
o Find carbonyl peak (C-O) at wavenumber 1775 cm-1 and recorded peak area
o Find methylene peak (-CH2) at wavenumber 2870 cm-1 and recorded peak area
o Determined the carbonyl index (CI) for specimen: CI =
Area C−O
Area C−H

27. Infrared Spectrophometry: FTIR
C-O

28. Infrared Spectrophometry: FTIR

29. Infrared Spectrophometry: FTIR
Sample Area C-O Area C-H CI
Unexposed PEX 1.320 106.041 0.0124
Left Side PEX 12.256 494.212 0.0248
Right Side PEX 5.454 282.283 0.0193
 Carbonyl Index Comparison:
 There was no significant difference
between Unexposed and Exposed PEX
 The CI was relatively low (lower than 0)
demonstrated that there was no
significant oxidative degradation in the
process
 But!!! “There was a trend” showing a
slight change in the CI:
 Left Side > Right Side > Unexposed

30. Analysis of Oxidized PEX
Tensile Testing
0
2000000
4000000
6000000
8000000
10000000
12000000
14000000
0 0.2 0.4 0.6 0.8 1 1.2 1.4
Stress(N/m2)
Strain
Left PEX Sample 2: Stress-Strain Curve
Elastic Limit = 11.80 MPa
UTS = 13.00 MPa

31. Analysis of Oxidized PEX
Tensile Testing
0
2000000
4000000
6000000
8000000
10000000
12000000
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35
Stress(N/m2)
Strain
Right PEX Sample 3: Stress-Strain Curve
Elastic Limit = 9.76 MPa
UTS = 10.40 MPa

32. Analysis of Oxidized PEX
Tensile Testing
0
2000000
4000000
6000000
8000000
10000000
12000000
14000000
16000000
18000000
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
Stress(N/m2)
Strain
Unexposed PEX Sample3: Stress-Strain Curve
Elastic Limit = 14.00 MPa
UTS = 17.10 MPa

33. Analysis of Oxidized PEX
Tensile Testing
Summary of Results
Left
PEX Sample 2:
Right
PEX Sample 3:
Unexposed
PEX Sample 3:
Elastic Limit (MPa) 11.80 9.76 14.00
Ductility Moderate Least Most
PEX Oxidation Moderate Most Least

34. Conclusions
Conclusion: The effect of exposure on PEX
PEX Specimens Visual Assessment FTIR Tensile
Exposed Left Microcrack Most Middle
Exposed Right N/A Middle Most
Unexposed N/A Least Least
However, there was no significant difference between left exposed and right exposed one
The least evidence of oxidation was observed on unexposed PEX

35. Further Study
Recommendation:
1. Examine specimens by using DSC
2. Set up the temperature higher (i.e. 30℃ 40℃)
3. Set up the concentration of chorine higher (i.e. 4.2ppm 8.0ppm)
4. Run the experiment longer (i.e. 1 hour 2 hours)

36. Reference
Angelo, P. (2018). CNG633: Fundamentals of Chemical Engineering II:
Transport Phenomina. Toronto: Sececa College of Applied Arts &
Technology: School of Biological Sciences & Applied Chemistry.
Lee, R., Bhatia, D., Hasnain, A. (2018). Fluid Mechanics Studies Lab
report Pilot plant 15. Toronto, ON.
Lee, R., Bhatia, D., Hasnain, A. (2018). Heat Transfer Studies Lab
report Pilot plant 15. Toronto, ON.

37. THANK YOU