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TGA‐DTAGroup 4
Norazana, Daniel, Johan
BiofuelsGS‐2
Analytical techniques in combustion
Part 4, ÅA
• Comparison of DTA and TGA techniques
• Group works
G1. Indium (DTA)
G3. Oxalate (TGA)
G2. KCl (TGA‐DTA)
G5. K2SO4 (TGA‐DTA)
G4. KCl‐K2SO4 eut mix (TGA‐DTA)
Presentation outline
Method approval
Phase diagram
DTA‐TGAone instrument – two functions
DTA
• Temperature difference
• Thermocouple
• Structural changes– Chrystallization
– Melting
• Chemical reactions causing temperature changes
TGA
• Mass change
• Microbalance
• Mass change by phase transition– Vaporization
– Sublimation
• Mass change by chemical reactions
Indium
• Standard for DTA
• Melting point:– Litterature: 156,6°C– Experimental: 153,95 °C
Method: Blank In-Al 25-700 °C_LF 25.0-700.0°C 30.00°C/min N2 50.0 ml/min
Method Name: Blank In-Al 25-700 °C_LF
Experiment: In-Al 25-700 °C_LF, 22.09.2009 16:10:35
SDTA In-Al 25-700 °C_LF,23.09.2009 10:29In-Al 25-700 °C_LF, 181.3201 mg
°C
-2.2
-2.0
-1.8
-1.6
-1.4
-1.2
-1.0
-0.8
-0.6
-0.4
-0.2
0.0
0.2
0.4
min
°C50 100 150 200 250 300 350 400 450 500 550 600 650
0 2 4 6 8 10 12 14 16 18 20
^exo
SW 8.10eRTASLab: METTLER
Integral -37.96 s°C normalized -0.21 ks°Cg -̂1Onset 153.95 °CHeating Rate 30.00 °Cmin -̂1Result Mode Sample Temp
[]SDTA In-Al 25-700 °C_LF,23.09.2009 10:In-Al 25-700 °C_LF, 181.3201 mg
°C
-1.4
-1.2
-1.0
-0.8
-0.6
-0.4
-0.2
0.0
min
°C120.0 130.0 140.0 150.0 160.0 170.0 180.0 190.0 200.0 210.0 220.0 230.0 240.0 250.0 260.0 270.0 280.0
3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 8.5
^exo
SW 8.10eRTASLab: METTLER
Calcium oxalate, CaC2O4•H2O
• Common material to show the TGA performance
• Step 1: release of water
• Step 2: release of CO
• Step 3: release of CO2
Module: TGA/SDTA851e/LF1600/UMT5/552, 01.12.2004 14:28:43
Method Name: Blank, no Lid, Oxalate
Experiment: oxalate group 3, 22.09.2009 09:36:40
!oxalate group 3oxalate group 3, 7.0000 mg
%
40
50
60
70
80
90
100
min
°C50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800 850 900
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44
SW 8.10eRTASLab: METTLER
-H2O
-CO
-CO2
KCl‐K2SO4 experiments
• In these experiments the 2 pure salts and an eutectic mixture were analyzed by DTA‐TGA
• The results were compared with theoretical values
• In order to create a complete phase diagram of a salt mixture the melting behavior of the pure salts and several mixtures are needed.
Method KCl Pure KCl
KCl – K2SO4 eutectic mixture
ExpectedMp(KCl): 771 °CMp(Eut.): 690 °C
Temp prog.Start T: 25 °CEnd T: 830 °CHeating rate: 20 °C/minGas: N2Flow rate: 50 ml / min
1
N250 ml/min
°C
0
100
200
300
400
500
600
700
800
900
1000
min0 5 10 15 20 25 30 35 40 45 50
TG KCl blank 25-830_LF 22.09.2009 12:39:36
SW 8.10eRTASLab: METTLER
Pure KCl
• Melting point:– Litterature: 771 °C
– Experimental: 770,29 °C
Integral -66.57 s°C normalized -12.80 ks°Cg -̂1Onset 770.29 °CHeating Rate 20.00 °Cmin^-1Result Mode Sample Temp
[]SDTA KCl_100%_group2,22.09.2009 14:52:KCl_100%_group2, 5.2000 mg
°C
-2.4
-2.2
-2.0
-1.8
-1.6
-1.4
-1.2
-1.0
-0.8
-0.6
-0.4
-0.2
min
°C620 640 660 680 700 720 740 760 780 800 820
29 30 31 32 33 34 35 36 37 38 39
^exo
SW 8.10eRTASLab: METTLER
SDTA KCl_100%_group2,22.09.2009 14:52:35KCl_100%_group2, 5.2000 mg
°C
-2.5
-2.0
-1.5
-1.0
-0.5
0.0
0.5
min
°C50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38
^exo
SW 8.10eRTASLab: METTLER
Pure K2SO4
• Phase transition:– Litterature: 587 °C
• Melting point:– Litterature: 1069 °C
Method: Blank + Lid_K2SO4 100%_25-1090_LF 25.0-1090.0°C 20.00°C/min N2 50.0 ml/min
Experiment: K2SO4 100%_25-1090_Group 5, 23.09.2009 13:49:24
SDTA !K2SO4 100%_25-1090_Group 5,K2SO4 100%_25-1090_Group 5, 4.1000 mg
°C
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
0.2
0.4
0.6
0.8
min
°C50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800 850 900 950 1000
0 5 10 15 20 25 30 35 40 45 50
^exo
SW 8.10eRTASLab: METTLER
???
Correct Baseline ??
Phase transition and meltingExperimental
• 582,54 °C • 1071,94 °C
Integral -20.93 s°C normalized -5.10 ks°Cg -̂1Onset 1071.94 °CHeating Rate 20.00 °Cmin^-1Result Mode Sample Temp
[]SDTA ! K2SO4 100%_25-1090_Group 5,K2SO4 100%_25-1090_Group 5, 4.1000 mg
°C
-1.8
-1.6
-1.4
-1.2
-1.0
-0.8
-0.6
min
°C1000.0 1005.0 1010.0 1015.0 1020.0 1025.0 1030.0 1035.0 1040.0 1045.0 1050.0 1055.0 1060.0 1065.0 1070.0 1075.0 1080.0 1085.0
48.6 48.8 49.0 49.2 49.4 49.6 49.8 50.0 50.2 50.4 50.6 50.8 51.0 51.2 51.4 51.6 51.8 52.0 52.2 52.4 52.6 52.8 53.0
^exo
SW 8.10eRTASLab: METTLER
Integral -4.21 s°C normalized -1.03 ks°Cg -̂1Onset 582.54 °CHeating Rate 20.00 °Cmin^-1Result Mode Sample Temp
°C
-0.10
-0.05
0.00
0.05
0.10
0.15
min
°C520.0 530.0 540.0 550.0 560.0 570.0 580.0 590.0 600.0 610.0 620.0 630.0 640.0 650.0
25.0 25.5 26.0 26.5 27.0 27.5 28.0 28.5 29.0 29.5 30.0 30.5 31.0
^exo
SW 8.10eRTASLab: METTLER
Sample preparationKCl – K2SO4 eutectic mixture
• 26 mole‐% K2SO4
• 74 mole‐% KCl
• 45 mg K2SO4
• 55 mg KCl
TGA curveKCl – K2SO4 eutectic mixture
!KCL-K2SO4 eut.mixt. 25-830°C_Group 4KCL-K2SO4 eut.mixt. 25-830°C_Group 4, 4.2000 mg
%
83
84
85
86
87
88
89
90
91
92
93
94
min
°C50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38
SW 8.10eRTASLab: METTLER
SDTA curveKCl – K2SO4 eutectic mixture
Integral -56.01 s°C normalized -13.34 ks°Cg -̂1Onset 683.85 °CHeating Rate 20.00 °Cmin^-1Result Mode Sample Temp
Integral -2.07 s°C normalized -0.49 ks°Cg -̂1Onset 580.08 °CHeating Rate 20.00 °Cmin^-1Result Mode Sample Temp
Method Name: KCl blank 25-830_LF
Experiment: KCL-K2SO4 eut.mixt. 25-830°C_Group 4, 24.09.2009 10:09:58
!SDTA KCL-K2SO4 eut.mixt. 25-830°C_GroupKCL-K2SO4 eut.mixt. 25-830°C_Group 4, 4.2000 mg
k°Cg -̂1
-0.50
-0.45
-0.40
-0.35
-0.30
-0.25
-0.20
-0.15
-0.10
-0.05
0.00
0.05
min
°C50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38
SW 8.10eRTASLab: METTLER
Integral -5.48 s°C normalized -1.30 ks°Cg -̂1Onset 579.42 °CHeating Rate 20.00 °Cmin -̂1Result Mode Sample Temp
°C
-0.14
-0.12
-0.10
-0.08
-0.06
-0.04
-0.02
0.00
0.02
0.04
min
°C530.0 540.0 550.0 560.0 570.0 580.0 590.0 600.0 610.0 620.0 630.0 640.0
25.5 26.0 26.5 27.0 27.5 28.0 28.5 29.0 29.5 30.0 30.5 31.0
^exo
SW 8.10eRTASLab: METTLER
Phase transformation peakKCl – K2SO4 eutectic mixture
Phase Transformation 587 °C
Integral -51.87 s°C normalized -12.35 ks°Cg -̂1Onset 683.87 °CHeating Rate 20.00 °Cmin^-1Result Mode Sample Temp
k°Cg -̂1
-0.50
-0.45
-0.40
-0.35
-0.30
-0.25
-0.20
-0.15
-0.10
-0.05
0.00
min
°C630.0 640.0 650.0 660.0 670.0 680.0 690.0 700.0 710.0 720.0 730.0
30.0 30.5 31.0 31.5 32.0 32.5 33.0 33.5 34.0 34.5 35.0
SW 8.10eRTASLab: METTLER
Melting peakKCl – K2SO4 eutectic mixture
Mp. 690 °C
TGA‐DTAKCl – K2SO4 eutectic mixture
°C
-2.2
-2.0
-1.8
-1.6
-1.4
-1.2
-1.0
-0.8
-0.6
-0.4
-0.2
0.0
0.2
min
°C50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38
%
83
84
85
86
87
88
89
90
91
92
93
94
min0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38
^exo
SW 8.10eRTASLab: METTLER
DTA
TGA
[°C] KCl Eut. Mix. K2SO4
PT theory ‐ 587 587
PT exp. ‐ 580,08 582,54
MP theory 771 690 1069
MP exp. 770,29 683,85 1071,94
PT = phase transition
MP = melting point
Summary
Conclusions
• KCl and K2SO4 system:
DTA results are in good agreement with the theoretical phase diagram
• Depending on fuel mixtures the melting range of the possibly forming salts have to be taken into careful consideration
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