Sample Purity: The Effect of Sample System Lines and Dead Legs Swagelok Company IFPAC 2013

Transcription

1 Sample Purity: The Effect of Sample System Lines and Dead Legs Swagelok Company IFPAC 2013

2 NeSSI to the Rescue 80% of analyzer problems are due to the sample system Question 1: Why??? Question 2: Can NeSSI REALLY help with this?

3 System Design What is really meant by 80% of the problems? Cal Gas Inlet It s red! PI PI Sample Inlet 1000 cc/min FI Analyzer 100 cc/min Lab Sample FI Bypass Flow 900 cc/min

4 NeSSI to the Rescue 80% of analyzer problems are due to the sample system Question 1: Why??? 1. Poor component selection for the application 2. Malfunctioning components 3. Sample is not representative Question 2: Can NeSSI REALLY help with this?

5 NeSSI to the Rescue How can NeSSI help with poor component selection? Case Study Results NeSSI = 86% faster at reconfiguring systems

6 NeSSI to the Rescue How can NeSSI help with malfunctioning components? Case Study Results NeSSI = operators can manage 2.7 times the number of systems

7 NeSSI to the Rescue How can NeSSI help with improving sample representation? Is the sample system supplying a representative sample? How long does it take to acquire a pure sample? How would we even know what level of representation is achieved?

8 Application Example 25.0% Percent Concentration 20.0% 15.0% 10.0% System Inlet 5.0% 0.0% Time (sec)

9 Application Example 25.0% Percent Concentration 20.0% 15.0% System Inlet 10.0% Nitrogen 5.0% 0.0% Time (sec)

10 Application Example 25.0% 20.0% Percent Concentration What if we take a liquid sample after 30 seconds? 15.0% 10.0% System Inlet Nitrogen Water 5.0% 0.0% Time (sec)

11 NeSSI to the Rescue How can NeSSI help with improving sample representation? Each concentration line can be characterized by a series of equations. Variables include: Flow rate Viscosity System volume Wall finish Component entrapment 25.0% 20.0% 15.0% 10.0% 5.0% Percent Concentration 0.0% Time (sec) System Inlet Nitrogen Water

12 Historical Approach Length of Tube Estimation of the time for a representative sample to reach the analyzer assumed slug flow All fluid flows at average velocity Analyzer Actual velocity profile is not uniform slowest at tube walls Analyzer

13 Flow Geometry Tube Lengths (0.5m, 1.0m, 2.0m, 4.0m) Tube with Dead Legs (0.5m, 1.0m, 2.0m, 4.0m) Dead Leg Geometry (L/D), where L = Length of Dead Leg D = Inner Diameter of Tube

14 Remaining Mass Fraction of Original Solution CFD Simulation Results Tee Dead Legs 1 CFD - Water 5x 5:1 Dead Legs on 1/4 x.035" Tube 20 in Dead Leg Purge Time (sec)

15 Remaining Mass Fraction of Original Fluid CFD Results Tee Dead Legs Varied Length of Leg Nitrogen 100 sccm CFD Results Nitrogen - Varied L/D 1 Tee Dead Leg on 1/4 x 0.035" Tube 1.00E E-01 N2 L/D = 1 8 in. Tube N2 L/D =2 8 in. Tube 1.00E-02 N2 L/D =4 8 in. Tube 1.00E-03 N2 L/D = 6 8 in. Tube 1.00E Time (s)

16 Remaining Mass Fraction of Original Solution CFD Simulation Results Tee Dead Legs DV Lag Tee Dead Legs on 1/4 x.035" Tube 20 in CFD - Water 100 cc/min 1 Center of Tube Purge 0.1 Walls of Tube Purge CFD 5x Tee Dead Leg CFD 3x Tee Dead Leg 0.01 Dead Leg Purge CFD 1x Tee Dead Leg CFD 20 in. tube Historical Slug Flow Time (sec)

17 Internal Component Entrapment NPT Expansion to mixing volume at threaded joint Physical Parts Fluid Volume for CFD

18 Internal Component Entrapment Socket Weld Connection Gap at bottom of tube Physical Parts Fluid Volume for CFD

19 Internal Component Entrapment Swagelok Tube Fitting Connection Small diameter change Fluid Volume for CFD

20 Remaining Mass Fraction of Original Fluid Water 100 cc/min 1.00E+00 CFD Results Comparison of Fitting Designs on 1/4 x 0.035" Tube 8 in. long Water cc/min 1.00E E-02 1x Weld Fitting on 8 in. tube 1x NPT Fitting on 8 in. tube 1.00E E-04 1x Swagelok Tube Fitting on 8 in tube 8in tube 1.00E E Time (s)

21 Component Analysis Areas of low velocity Other Components (flow meter, filter, etc.)

22 Component Analysis Areas of low velocity Filter From Process 100 cc/min From Process 1000 cc/min To Analyzer 100 cc/min Cal Gas Inlet PI Bypass Flow 900 cc/min Sample Inlet FI Analyzer PI Lab Sample FI Bypass Flow

23 Remaining Mass Fraction of Original Fluid Water 100 cc/min 1.00E+00 CFD Results Comparison of 4TF with and without bypass Water cc/min to the analyzer 1.00E E-02 4TF without bypass 1.00E E-04 4TF with bypass 1.00E E Time (sec)

24 Component Analysis Areas of low velocity Flowmeter Cal Gas Inlet Sample Inlet PI FI Analyzer PI Lab Sample FI Bypass Flow

25 Remaining Mass Fraction of Original Fluid Water 100 cc/min 1.00E+00 CFD Results Flowmeter with 1/4" NPT Ends and 1/4 x 0.035" Tube 8 in. Long Water cc/min 1.00E E E-03 Flowmeter 1x w/ 1/4" NPT 1.00E E E Time (sec)

26 System Design Causes of Sample Contamination Original System (2 meters long) 18x NPTs Fitting 5x deadlegs Non-bypass filter Cal Gas Inlet PI PI Sample Inlet 1000 cc/min FI Analyzer 100 cc/min Lab Sample FI Bypass Flow 900 cc/min

27 System Design Causes of Sample Contamination Improved System (2 meters long) Cal Gas Inlet 2x NPT Fitting 1x PTX flow through pressure transducer Bypass filter 6x Swagelok Tube Fitting Sample Inlet PI FI Analyzer 100 cc/min PI Lab Sample FI Bypass Flow 900 cc/min

28 Remaining Mass Fraction of Original Fluid CFD Results System Comparison Water 100 cc/min 1.00E+00 CFD Results Comparison of Two Sampling Systems Water cc/min 1.00E E-02 Original System 1.00E E-04 Improved System 1.00E E Time (sec)

29 How Can NeSSI Help?

30 NeSSI to the Rescue How can NeSSI help with improving sample representation? Each concentration line can be characterized by a series of equations. Variables include: Flow rate Viscosity System volume Wall finish Component entrapment 25.0% 20.0% 15.0% 10.0% 5.0% Percent Concentration 0.0% Time (sec) System Inlet Nitrogen Water

31 NeSSI to the Rescue Reduction in footprint results in a reduction in volume Case Study Results NeSSI Gen 1 = 72% reduction in volume (Dimensions in mm)

32 NeSSI to the Rescue All NeSSI pieces are precision machined with polished surfaces

33 NeSSI to the Rescue How can NeSSI help? Each piece of the system is well defined. These can be optimized for best purity.

34 Remaining Mass Fraction of Original Fluid NeSSI to the Rescue The NeSSI connection is a smooth bore connection, similar to a compression fitting 1.00E+00 CFD Results Comparison of Fitting Designs on 1/4 x 0.035" Tube 8 in. long Water cc/min 1.00E E-02 1x Weld Fitting on 8 in. tube 1x NPT Fitting on 8 in. tube 1.00E E-04 1x Swagelok Tube Fitting on 8 in tube 8in tube 1.00E E Time (s)

35 Purge: Typical SP76 NPT Pressure Sensor Flow: 100sccm

36 Purge: Purge SP76 / MPC PTX Flow: 100sccm

37 Remaining Mass Fraction of Original Fluid Predicting System Response of a NeSSI System Curve Fit Prediction - Water Predicted Response of Concentration vs Time of System 1 60in tube 1 Tee Dead Leg Predicted in tube 4 Socket Welds Predicted in tube 2 NPTs Predicted 60in tube 1 Mixing Volume Predicted 60in tube only Predicted System Predicted Time (s)

38 System Design Causes of Sample Contamination System comparisons Original System (16x NPTs, 5x deadlegs, non-bypass filter) Improved System (NeSSI unit) Real World Example #1: Measuring Pentane Concentration Stream #1: 20% Pentane in Hexane Stream #2: 2% Pentane in Hexane Stream #3: 0.2% Pentane in Hexane

39 Analyzer Reading Concentration of Pentane System Comparison Pentane Changing from 2% to 20% Analyzer Reading % Comparison of Two Sampling Systems Analyzer Reading Pentane Changing from 2% to 20% % Actual Stream Chemistry 19.99% Pentane -0.03% error 20.00% 0.00% error 20.00% 0.00% error 19.4% -2.9% error 0.15 % % 10.2% Pentane -41% error 17.8% -11% error Actual Stream Chemistry Original System Improved System % 2% 0 % Time (sec)

40 Analyzer Reading Concentration of Pentane System Comparison Pentane Changing from 20% to 2% Analyzer Reading % Comparison of Two Sampling Systems Analyzer Reading Pentane Changing from 20% to 2% % Actual Stream Chemistry Original System 0.15 % Improved System % 10.2% Pentane 410% error % 2.01% Pentane 0.27% error 2% Actual Stream Chemistry 2.00% 0.01% error 0 % Time (sec) 4.2% 109% error 2.6% 29% error 2.00% 0.00% error

41 Analyzer Reading Concentration of Pentane System Comparison Pentane Changing from 20% to 0.2% Analyzer Reading % Comparison of Two Sampling Systems Analyzer Reading Pentane Changing from 20% to 0.2% % Actual Stream Chemistry Original System 0.15 % Improved System % 9.2% Pentane 4520% error % 0.21% Pentane 0.20% 2.9% error 0.84%, 320% error 0.02% 0.12% error 0 % %, 0.00% error Time (sec) 2.6% 1200% error

42 Remaining Mass Fraction of Original Fluid Predicting System Response of a NeSSI System 80% of analyzer problems are due to the sample system NeSSI will help address that Immediate analysis of system purity Design optimization BEFORE procurement Component precision and design for best analyzer measurement Curve Fit Prediction - Water Predicted Response of Concentration vs Time of System 60 1 P 60 4 P P 60 1 P 60 P S P Time (s)

43 Thank You