CCQTA TVP Project Update

Transcription

1 CCQTA TVP Project Update HPLIS/Gas Chromatograph vs ASTM D6377 VPCR Results Cameron Konecnik, P.Eng October 30 th, 2014

2 Outline 1) Review the rational for CCQTA TVP Project initiation in ) 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

3 Average Vapor Pressure (psi) Rational for CCQTA Project Initiation TransCanada/Maxxam 2012 Vapor Pressure Study on Mixed Sweet Crude D6377 D323M D323C D323A Vapor Pressure Method 3

4 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

5 ASTM D6377 VPCR 4 (100 o F) Other Significant Results from TVP Project ASTM D6377 VPCR 4 (100 o F) Results vs Sample Collection Method Constant Volume Cylinder Floating Piston Cylinder 5

6 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

7 Pressure (psi) Other Significant Results from TVP Project ASTM D323A RVP vs ASTM D6377 VPCR 4 (100 o F) RVP VPCR4(100oF) 7

8 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 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*VPCR 4 (100 o F). This is fairly close to the specified multiplier recommended within the Appendix of the ASTM D Standard. However, 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

9 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

10 HPLIS Results for SWB Sample 10

11 Pressure (psi) Vapor Pressure for SWB Sample Temperature ( o F) Rault's Law (All) Rault's Law (EPA) VPCR4 TVP/RVP RVPE = 0.834*VPCR 4 C5+ Mass% = 5.4% C3 + C4 Mass% = 2.9% 11

12 HPLIS Results for WCS Sample 12

13 Pressure (psi) Vapor Pressure for WCS Sample Rault's Law (All) VPCR0.2 Rault's Law (EPA) VPCR4 TVP/RVP Temperature ( o F) RVPE = 0.834*VPCR 4 C5+ Mass% = 8.5% C3 + C4 Mass% = 2.7% 13

14 HPLIS Results for KH Sample 14

15 Pressure (psi) Vapor Pressure for KH Sample Rault's Law (All) VPCR0.2 Rault's Law (EPA) VPCR4 TVP/RVP Temperature ( o F) RVPE = 0.834*VPCR 4 C5+ Mass% = 10.2% C3 + C4 Mass% = 0.8% 15

16 HPLIS Results for SHB Sample 16

17 Pressure (psi) Vapor Pressure for SHB Sample Temperature ( o F) Rault's Law (All) VPCR0.2 Rault's Law (EPA) VPCR4 TVP/RVP RVPE = 0.834*VPCR 4 C5+ Mass% = 2.5% C3 + C4 Mass% = 0.6% 17

18 HPLIS Results for CL Sample 18

19 Pressure (psi) Vapor Pressure for CL Sample Temperature ( o F) Rault's Law (All) VPCR0.2 Rault's Law (EPA) VPCR4 TVP/RVP RVPE = 0.834*VPCR 4 C5+ Mass% = 6.6% C3 + C4 Mass% = 1.0% 19

20 HPLIS Results for CDB Sample 20

21 Pressure (psi) Vapor Pressure for CDB Sample Rault's Law (All) VPCR0.2 Rault's Law (EPA) VPCR4 TVP/RVP Temperature ( o F) RVPE = 0.834*VPCR 4 C5+ Mass% = 7.1% C3 + C4 Mass% = 0.6% 21

22 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. VPCR 4 results from ASTM D6377 are highly repeatable and reproducible (TCPL vs AITF testing & TCPL duplicate tests). The multiplier relating VPCR 4 to RVPE may be satisfactory on average. However, it should be highly suspect for both highly stable and highly volatile crudes. 22

23 Observations and Conclusions The initial hypothesis that the VPCR 0.2 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 VPCR 4 provides much more confidence than does the RVP + nomograph method. The initial hypothesis that the VPCR 4 may be equivalent to the EPA defined TVP does show promise with the first 6 samples. Current testing shows the VPCR 4 to be conservative on average but is near exact for crudes with a relatively high C3 and C4 fraction (winter blend crudes). 23

24 Questions 24