Page 1 Interface Level Measurement with Emulsions Richard von Brecht B ECHTEL 2008 API Spring Refining and Equipment Standards Meeting
Page 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
Page 3 Typical Measurement Problems 50% Water-Oil Point Read Vapor-HC reading can’t overlap the HC-Water reading Density variances magnified Measured mid point drifts away from the true mid point
Page 4 Installation Methods Two Tap External Installation Multi-Tap External Installation Direct probe installation
Page 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
Page 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
Page 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
Page 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
Page 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
Page 10 Summary Displacer Differential Pressure RF Admittance/Capacitance Microwave Absorption Guide Wave Radar