Interface Level Measurement with Emulsions

1

2008 API Spring Refining and Equipment Standards
Meeting

• Interface Level Measurement with Emulsions
• Richard von Brecht
• BECHTEL

2
Interface Level Measurement Methods

• Displacer (Negative Buoyancy)
• Magnostrictive (Positive Buoyancy)
• Traversing Nuclear Detector
• Sounding Probe
• Differential Pressure
• RF Admittance/Capacitance
• Microwave Absorption
• Guide Wave Radar

3
Typical Measurement Problems

• 50 Water-Oil Point Read
• Vapor-HC reading cant overlap the HC-Water
  reading
• Density variances magnified
• Measured mid point drifts away from the true mid
  point

4
Installation Methods

• Two Tap External Installation
• Multi-Tap External Installation
• Direct probe installation

5
Displacer

• Traditional method for interface measurement
• Four sizes from 14 to 60 for economic and
  mechanical reasons
• Mechanical, less reliable than other devices
• Calibration procedure complex
• Density variance effects are almost doubled
• Problems with coatings

6
Differential Pressure

• Well understood, most widely use for standard
  level measurement
• Continuing to evolve in accuracy, reliability and
  communication capabilities
• Avoids drifting and coating issues
• Maintain a constant leg composition
• Sensitive to density variance

7
RF Admittance/Capacitance

• Mature technology
• Calibrated for the conductive water phase
• In-situ calibration for low dielectric fluids
• Can measure interface over the entire vessel
• Temperature issues
• Can compensate to some extent for coatings

8
Microwave Absorption

• Measures water
• Not influenced by coatings
• Un-affected by vessel geometry
• Probe maintainable online
• Bench calibrated
• Maximum range four feet
• Requires external power

9
Guided Wave Radar

• Bench calibrated, un-affected by vessel
• Coating influence less
• Maximum range 150 feet
• Works with boiling fluids
• Measures the upper layer
• Mixed results with emulsions
• Probe not maintainable online

10
Summary

• Displacer
• Differential Pressure
• RF Admittance/Capacitance
• Microwave Absorption
• Guide Wave Radar