1. AC Analytical Controls January 2001
Simdis Course
AC Analytical Controls
January 2001

2. Simdis - Introduction
Distillation is the most widely used separation process in the petrol industry
Knowledge of the boiling range is essential for quality assurance regulatory compliance refinery process control physical property predictions

3. Simdis Vs. Physical Distillation
D86, D1160 generates an average boiling point of a mixture at a given point
D 2892, 15 theoretical plate, true boiling point
Time consuming, labor intensive, imprecise

4. Simdis Vs Physical Distallation
GC analysis simulates a “true boiling point”
Simdis provides TBP of the individual components in a mixture at a given point
Automated
Accurate results
Fast
Detection of contamination or entrainment

5. Simdis Theory
The technique of simulated distillation is based upon the assumption that individual components of a sample elute from a GC column in order of their boiling point.

6. Available Simdis Methods
Final boiling point
ASTM °C
ASTM °C
2887 extended °C
Ht °C

7. ASTM D 3710 Gasoline, naphtha, kerosene
Final boiling point (FBP)<260°C
Packed or capillary column

8. ASTM D 2887 Petroleum products Final boiling point (FBP)<538°C
Packed or capillary column
Cryogenic option

9. ASTM D 2887 Extended Petroleum products
Final boiling point (FBP)<620°C
Capillary column
Cryogenic option

10. Ht 750 Crude's and crude fractions, petroleum products
Boiling range from 35°C-750°C
Capillary column
Cryogenic option

11. Requirements non-polar stationery phase linear temperature program
compensation of column bleeding

12. Hardware Gas chromatograph
Programmable temperature vaporizer (PTV injector)
FID detector
Column

13. Typical Gas Chromatograph
Mol-Sieve
Fixed
Traps
Restrictors
Injection
Port
Regulators
Detector
Electrometer
Flow PC
Controller
Column
Carrier
Hydrogen
Air
Gas

14. PTV

15. Flame Ionization Detector Schematic
FID Detector
Assembly
Air
Inlet
Capillary Column
End-Position
(1-2 mm from Top of Jet)
Jet
H2 Inlet +
Make-Up
Exit End of Column

16. Flame Ionization Detector
The FID is a destructive, mass sensing detector.
Cations generated in the flame are counted and produce the detector signal.
Analytes that have the greatest number of low oxidation state carbons produce the largest signal. H 2 CH 4
CHO + CO
H 0
Column
Jet

17. System Startup Electrical connections Gas connections – carrier, FID
GC and auto sampler configuration
Installation of liner & column
Installation of septum and syringe
Check flows

18. Simdis Theory
A n-paraffin standard is analyzed to determine retention times
The times relate to the n-paraffin boiling points
A boiling point calibration curve is created by the software

19. AC SIMDIS D 2887 Calibration
AC SIMDIS Analyzers

20. Calibration Report
AC SIMDIS Analyzers

21. Calibration Curve
AC SIMDIS Analyzers

22. Boiling Point Curve
AC SIMDIS Analyzers

23. Simdis Theory Every analysis should be corrected for column bleeding
Analyze a blank in every sequence
The blank signal is automatically subtracted from every sample and reference signal

24. Simdis Theory The net signal is used to determine boiling points
IBP at 0.5 % of the total area
FBP at 99.5 % of the total area
The total area lies between start and end elution point
The start and end time are determined by elution algorithms

25. Simdis Theory
A reference sample is analyzed to check system performance

26. AC SIMDIS D 2887 Reference
AC SIMDIS Analyzers

27. AC SIMDIS D 2887 reference reports
AC SIMDIS Analyzers

28. AC SIMDIS D 2887 Reference Reports
AC SIMDIS Analyzers

29. Starting Analysis Make & run a sequence Calibration Observe results
Reprocess if necessary

30. Non Fitting Blank Chromatogram: Boiling point (°C) Signal5 10 15 20 25 30 35 40 45
Retention time (min)
5000
10000
15000
20000
25000
30000
35000
40000
45000
50000
55000
60000
65000
70000
Signal
100
200
300
400
500
600
700
800
Boiling point (°C)
Start Time
End Time
IBP
FBP

31. End Time Found Incorrectly
Chromatogram: 5 10 15 20 25 30 35 40 45 50 55
Retention time (min)
200
400
600
800
1000
1200
1400
1600
1800
2000
2200
2400
2600
2800
3000
Signal
300
500
700
Boiling point (°C)
Start Time
End Time
IBP
FBP