CCQTA TVP Project Update
HPLIS/Gas Chromatograph vs ASTM D6377 VPCR Results
Cameron Konecnik, P.Eng
October 30th, 2014
Outline
1) Review the rational for CCQTA TVP Project initiation in 2012.
2) Review some other significant findings from within the TVP Project.
3) Review of the current Heated Pressurized Liquid Injection System (HPLIS)
and Gas Chromatograph Results vs ASTM D6377 Results.
4) Review the observations and conclusions from the CCQTA TVP Project to
date.
2
Rational for CCQTA Project Initiation
Average Vapor Pressure (psi)
TransCanada/Maxxam 2012 Vapor Pressure Study on Mixed Sweet Crude
12.0
11.5
11.0
10.5
10.0
9.5
9.0
8.5
8.0
7.5
7.0
6.5
6.0
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
D6377
D323M
D323C
D323A
Vapor Pressure Method
3
Rational for CCQTA Project Initiation
Conclusions from TransCanada/Maxxam Vapor Pressure Study
• Study was conducted in April 2012 on over 200 samples of a relatively
high vapor pressure Mixed Sweet crude. Testing was conducted to
examine the differences which may arise from sampling methodology
and testing methodology.
• For a given test method no material differences in final vapor
pressure results were observed when varying the sampling
methodology using the evacuated cylinder (flow through, brine
displacement or closed injection). Only the 80% full bottle collection
method showed lower results (light end loss).
• The 80% full bottle sample collection method (ASTM D323A method)
does not appear to be appropriate for higher vapor pressure crudes
due to significant light end loss (sampling loss, air saturation loss,
sample loading loss).
• ASTM D6377 showed the highest recorded vapor pressures and the
tightest repeatability out of all the methods tested. It was assumed
that this was due to preservation of the volatiles within the sample
and the effective design of the D6377 test chamber.
4
Other Significant Results from TVP Project
ASTM D6377 VPCR4(100oF) Results vs Sample Collection Method
11.0
10.5
10.0
9.5
9.0
ASTM D6377 VPCR4(100oF)
8.5
8.0
7.5
7.0
6.5
6.0
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
Constant Volume Cylinder
Floating Piston Cylinder
5
Other Significant Results from TVP Project
Conclusions from ASTM D6377 CVC vs FPC Testing
• Study was conducted in June 2013 on 12 samples collected over a few
days. Testing was conducted to examine the differences which may
arise from sampling methodology employed with ASTM D6377.
• In all cases the Floating Piston Cylinder results are higher than the
Constant Volume Cylinder results. This is expected since the CVC
samples must be subjected to atmosphere (light end loss) before
being drawn into the D6377 testing chamber.
• The very large difference between the FPC and CVC results on some
samples is not expected. Some other unknown factors were likely at
play (machine fouling??).
• Some difference could be attributed to the fact that the samples were
run at different labs on different machines.
6
Other Significant Results from TVP Project
10.0
ASTM D323A RVP vs ASTM D6377 VPCR4(100oF)
9.5
9.0
8.5
8.0
7.5
7.0
Pressure (psi)
6.5
6.0
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
RVP
VPCR4(100oF)
7
Other Significant Results from TVP Project
Conclusions from ASTM D323A vs ASTM D6377 Testing
• Study was conducted in September 2014 on 27 samples collected over
a week. Testing was conducted to confirm and re-validate the findings
from the TransCanada/Maxxam study in 2012.
• In all cases the ASTM D6377 Floating Piston Cylinder results are higher
than the ASTM D323A results.
• Average D323A/D6377 results indicate RVPE = 0.88*VPCR4(100oF).
This is fairly close to the specified 0.834 multiplier recommended within
the Appendix of the ASTM D6377-08 Standard.
However, 0.834
should not be taken as verbatim since testing showed the actual
values to fluctuate between 0.54 and 0.99 on these 27 samples.
8
HPLIS Development and Function
• HPLIS primary function is to facilitate a crude sample into a GC
column without subjecting the sample to atmosphere. Hence a crude
sample from a ASTM D3700 compliant cylinder can be injected into
the GC column directly through the HPLIS.
• Gas Chromatograph results (component mol%’s) can be used to
approximate the theoretical sample TVP either through Antoine
constants/Raoult’s Law or more sophisticated EOS software.
• TVP results are analyzed and compared with the ASTM D6377 curves
at various V/L ratios.
9
HPLIS Results for SWB Sample
10
Pressure (psi)
Vapor Pressure for SWB Sample
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Rault's Law (All)
Rault's Law (EPA)
VPCR4
TVP/RVP
75
80
85
90
95
100
105
110
115
Temperature
•
RVPE = 0.834*VPCR4
•
C5+ Mass% = 5.4%
•
120
125
130
135
140
145
150
(oF)
C3 + C4 Mass% = 2.9%
11
HPLIS Results for WCS Sample
12
Vapor Pressure for WCS Sample
32
30
28
26
24
22
Pressure (psi)
20
18
Rault's Law (All)
16
VPCR0.2
14
Rault's Law (EPA)
12
VPCR4
TVP/RVP
10
8
6
4
2
0
75
80
85
90
95
100
105
110
115
Temperature
•
RVPE = 0.834*VPCR4
•
C5+ Mass% = 8.5%
•
120
125
130
135
140
145
150
(oF)
C3 + C4 Mass% = 2.7%
13
HPLIS Results for KH Sample
14
Vapor Pressure for KH Sample
30
28
26
24
22
Pressure (psi)
20
18
Rault's Law (All)
16
VPCR0.2
14
Rault's Law (EPA)
12
VPCR4
10
TVP/RVP
8
6
4
2
0
75
80
85
90
95
100
105
110
115
Temperature
•
RVPE = 0.834*VPCR4
•
C5+ Mass% = 10.2%
•
120
125
130
135
140
145
150
(oF)
C3 + C4 Mass% = 0.8%
15
HPLIS Results for SHB Sample
16
Pressure (psi)
Vapor Pressure for SHB Sample
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Rault's Law (All)
VPCR0.2
Rault's Law (EPA)
VPCR4
TVP/RVP
75
80
85
90
95
100
105
110
115
Temperature
•
RVPE = 0.834*VPCR4
•
C5+ Mass% = 2.5%
•
120
125
130
135
140
145
150
(oF)
C3 + C4 Mass% = 0.6%
17
HPLIS Results for CL Sample
18
Pressure (psi)
Vapor Pressure for CL Sample
29
28
27
26
25
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Rault's Law (All)
VPCR0.2
Rault's Law (EPA)
VPCR4
TVP/RVP
75
80
85
90
95
100
105
110
115
Temperature
•
RVPE = 0.834*VPCR4
•
C5+ Mass% = 6.6%
•
120
125
130
135
140
145
150
(oF)
C3 + C4 Mass% = 1.0%
19
HPLIS Results for CDB Sample
20
Vapor Pressure for CDB Sample
32
30
28
26
24
22
Pressure (psi)
20
18
Rault's Law (All)
16
VPCR0.2
14
Rault's Law (EPA)
12
VPCR4
TVP/RVP
10
8
6
4
2
0
75
80
85
90
95
100
105
110
115
Temperature
•
RVPE = 0.834*VPCR4
•
C5+ Mass% = 7.1%
•
120
125
130
135
140
145
150
(oF)
C3 + C4 Mass% = 0.6%
21
Observations and Conclusions
• ASTM D323A will experience light end loss during sampling and testing.
This method does not appear to be appropriate for high vapor pressure
crudes.
• Current testing shows that for certain crudes with vapor pressures
between 2psi and 10psi light end loss can still occur when gathering
samples without a D3700 approved cylinder for ASTM D6377 testing.
• VPCR4 results from ASTM D6377 are highly repeatable and reproducible
(TCPL vs AITF testing & TCPL duplicate tests).
• The 0.834 multiplier relating VPCR4 to RVPE may be satisfactory on
average. However, it should be highly suspect for both highly stable
and highly volatile crudes.
22
Observations and Conclusions
• The initial hypothesis that the VPCR0.2 may be equivalent to “Bubble
Point TVP” does not show good correlation with the first 6 samples. A
lower V/L ratio may be more appropriate in estimating the “Bubble Point
TVP” through ASTM D6377.
• For TVP estimation (as defined by EPA for emissions regulations), ASTM
D6377 VPCR4 provides much more confidence than does the RVP +
nomograph method.
• The initial hypothesis that the VPCR4 may be equivalent to the EPA
defined TVP does show promise with the first 6 samples. Current
testing shows the VPCR4 to be conservative on average but is near exact
for crudes with a relatively high C3 and C4 fraction (winter blend
crudes).
23
Questions
24