Entrained Gas Management (EGM)

EGM was developed for OPTIMASS Coriolis mass flowmeters to overcome problems caused by air or gas entrainments in a liquid. Powerful control algorithms allow the flowmeter to maintain operation over a wide range of gas fractions and complex flow conditions, even during a complete transition from a pure liquid phase to a gas phase and back. Mass flow and density measurements remain stable and continuous, which has been demonstrated in batch/ loading/ empty-full-empty applications.

Entrained Gas Management (EGM)

EGM was developed for OPTIMASS Coriolis mass flowmeters to overcome problems caused by air or gas entrainments in a liquid. Powerful control algorithms allow the flowmeter to maintain operation over a wide range of gas fractions and complex flow conditions, even during a complete transition from a pure liquid phase to a gas phase and back. Mass flow and density measurements remain stable and continuous, which has been demonstrated in batch/ loading/ empty-full-empty applications.

  • Technology pioneer with over 8 years of experience

  • Standard for all OPTIMASS flowmeters without extra cost

  • Continuous measurement through complete transition from pure liquid phase to a gas phase and back (full-empty-full)

  • Process diagnostic: reliable detection and indication of 2-phase flows, air/gas entrainments

Entrained gas - required or unwanted?

Entrained gas may either be required for the process or the product (e.g. with aerated products) or occur as an unwanted side-effect caused by:

  • Leaking pumps

  • Cavitation

  • Vaporisation

  • Mixing of liquids

  • Empty-full-empty applications

  • Top filling tanks with long drops

How entrained air or gas affects the Coriolis flow measurement

With conventional Coriolis mass flowmeters, difficulties arise with entrained air or gas in the liquid, e.g. overreporting, or maintaining measurement. This is because the entrained air or gas affects the measurement.

Without entrained gas, the measuring tubes in the Coriolis mass flowmeter have the desired regular oscillation. Gas entrained in the liquid dampens this regular oscillation, and as the gas content increases, the oscillation can come to a complete stop.

To overcome this, KROHNE has developed powerful control algorithms for the OPTIMASS series of Coriolis flowmeters, and implemented them in a synthesised drive control.

Continuous operation even with complex flow regimes

The difficulty of measuring a liquid with entrained gas increases with the gas volume fraction (GVF). A number of other process factors such as temperature, increased viscosity, pressure, and the relative velocity between liquid and gas also affect the resulting flow regime.

EGM technology allows the flowmeter to maintain the oscillation with complex flow regimes. Even during a complete transition from a pure liquid phase to a gas phase and back, i.e. from 0 to 100% gas content, the device will continue to operate.

Benefits

EGM technology presents a number of advantages for your process:

  • Considerable improvements with plant start-up and shut-down, troubleshooting in the process: no more plant standstill due to gas bubble disturbance of meters

  • Uninterrupted measuring operation for coordinated dosing procedures without downtime

  • Reliable detection and indication of 2-phase flows or air/gas entrainments in the process

  • Added reliability for safety critical control functions  (SIS)

  • Gas separators can be much smaller or even be omitted

Watch our EGM Video

Applications

Typical applications for OPTIMASS flowmeters with EGM are:

Chemical
  • Production of polyurethane foams

Oil & Gas
  • Crude oil production

  • LNG loading/unloading

Food & beverage
  • Spinach production

  • Ice cream production

  • Yoghurt production

  • Mayonaise production

  • Beer production

Mass or density – both are possible even with gas entrainment

Density measurement of single-phase fluids is common practice, but for traditional meters it becomes challenging with entrained gas. In many applications where entrained gas is present, OPTIMASS flowmeters with EGM show excellent performance and repeatability for process control, batching, loading, unloading and transfer measurement.

Related products

OPTIMASS 6400

Coriolis mass flowmeter for advanced process applications

  • High accuracy (±0.05% flat), for cryogenic to high temperature media (-200…+400°C / -328…+752°F); maintains operation over a wide range of gas fractions and complex flow conditions (EGMTM)
  • SIL 2/3; CT: OIML R117, R137, MI-005, MI-002; API, AGA; hygienic certifications
  • Flange: DN10…300 / ½…12", max. PN 160 / ASME Cl 1500
  • 3 x 4…20 mA, HART®7, Modbus, FF, Profibus-PA/DP, PROFINET, EtherNet/IP™, Bluetooth®

OPTIMASS 2400

Coriolis mass flowmeter for highest capacity bulk measurement

  • For gases and liquids up to 4,600 t/h; maintains operation over a wide range of gas fractions and complex flow conditions (EGMTM)
  • CT: OIML R117, MI-005, MI-002; API and AGA compliant
  • Flange: DN100…400 / 4…16", max. PN160 / ASME Cl 1500
  • 3 x 4…20 mA, HART®7, Modbus, FF, Profibus-PA/DP, PROFINET, EtherNet/IP™, Bluetooth®

OPTIMASS 7400

Coriolis mass flowmeter for advanced process applications

  • High accuracy (±0.1%), for viscous, aggressive or shear-sensitive media; maintains operation over a wide range of gas fractions and complex flow conditions (EGMTM)
  • CT: OIML R117, MI-005; API; hygienic certifications
  • Flange: DN10…100 / ½…4", max. PN100 / ASME Cl 600; others
  • 3 x 4…20 mA, HART®7, Modbus, FF, Profibus-PA/DP, PROFINET, EtherNet/IP™, Bluetooth®

OPTIMASS 1400

Coriolis mass flowmeter for universal applications and process control

  • Mass, density and volume flow of gases and liquids; maintains operation over a wide range of gas fractions and complex flow conditions (EGMTM)
  • Also certified for hygienic use
  • Flange: DN15…100 / ½…4", max. PN100 / ASME Cl 600; many hygienic fittings
  • 3 x 4…20 mA, HART®7, FF, Profibus-PA/DP, Modbus, PROFINET, EtherNet/IP™, Bluetooth®

OPTIMASS 3400

Coriolis mass flowmeter for low flow and dosing applications

  • High accuracy (±0.1%) for gases and liquids >0.3 kg/h / 0.01 lb/min; maintains operation over a wide range of gas fractions and complex flow conditions (EGMTM)
  • Standard pressure rating up to 300 bar / 4351 psi
  • Flange: DN15 / 1/2"; also thread and clamp connections
  • 3 x 4…20 mA, HART®7, Modbus, FF, Profibus-PA/DP, PROFINET, EtherNet/IP™, Bluetooth®
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