1. Coriolis flowmeters measure flow using vibrating tubes that detect the twisting motion caused by the acceleration and deceleration of fluid passing through. Ultrasonic flowmeters send and receive ultrasonic signals across a pipe to measure the time it takes signals to travel in each direction. 2. Ultrasonic meters are well-suited for measuring natural gas flow in large pipelines due to their ability to handle large diameters. Coriolis meters are commonly used for liquid hydrocarbon distribution downstream of refineries. 3. The document recommends ultrasonic flowmeters for dry natural gas applications due to their suitability for large pipes, approval for custody transfer, and insensitivity to vibration. It notes requirements for

1. CORIOLIS VS. ULTRASONIC
FLOWMETERS

2. CORIOLIS VS. ULTRASONIC FLOWMETERS
Principal of
Operation
Coriolis flowmeters composed of one or more vibrating tubes—usually bent. The fluid to be measured
passes through the vibrating tubes.
The fluid accelerates as it passes towards the point of maximum vibration and decelerates as it leaves
this point. The result is a twisting motion in the tubes.
The degree of twisting motion is directly proportional to the fluid’s mass flow. Position detectors sense
the positions of the tubes.
Coriolis flowmeters
Ultrasonic flowmeters—transit time and Doppler.
Transit-time ultrasonic flowmeters have both a sender and a receiver.
They send an ultrasonic signal across a pipe at an angle, and measure the time it takes for the signal
to travel from one side of the pipe to the other.
When the ultrasonic signal travels with the flow, it travels faster than when it travels against the flow.
The ultrasonic flowmeter determines how long it takes for the signal to cross the pipe in one direction,
and then determines how long it takes the signal to cross the pipe in the reverse direction.
Ultrasonic flowmeters

3. CORIOLIS METER
Diameter range: DN 50 - 400 (2”-16”)
Std Operating Temp: -25 to +55 ºC
Pressure range: Up to 900# ANSI Class
Measurement channels: Measuring tubes
Explosion Proof: II 2G Ex ib IIB/IIC T1–T4/T5/T6 Gb
Accuracy limits: Liquid Acc.; +/- 0.05%
Gas Accuracy:+/- 0.25%
Repeatability: <0.05% of reading
Turndown: upto 80:1
Features: 4-20mA output
Frequency Output
Temperature Output
Density Output
Failure & alarm Indication
There are no pipe run requirements for sensors. Straight runs of
pipe upstream or downstream are unnecessary
Keep the sensor tubes full of process fluid.

5. GAS ULTRASONIC METER
Diameter range: DN 100 - 1050 (4”-42”)
Std Operating Temp: -20 to +100 ºC
Pressure range: Up to 2500# ANSI Class
Measurement channels: 4 Path(8 Transducer)
Explosion Proof: EEx d ia IIB T4(ATEX)
Accuracy limits: Dry calibration +/- 0.30%
Flow calibration +/- 0.10%
Repeatability: <0.05% of reading
Velocity range: 0.3m/s to 30+m/s
Turndown: Greater than 100 to 1
Features: Bi-Directional Flow available
P / T input( Compensation)
Retractable Transducers
Replaceable Transducer Wiring

7. CORIOLIS VS. ULTRASONIC FLOWMETERS
Ultrasonic meters excel in measuring the flow of natural gas. They are widely used for custody transfer
of natural gas on pipeline transmission lines, where the pipe sizes can get quite large. The AGA-9 Report
approves them for custody transfer of natural gas. Multipath meters are required for custody transfer of
natural gas.
Ultrasonic meters are widely used on both hydrocarbon liquids. Multipath ultrasonic flowmeters,
meaning those with three or more paths, are used to measure the custody transfer of hydrocarbon liquids.
Coriolis flowmeters are widely used to measure hydrocarbon liquids, especially for distribution
purposes downstream from a refinery. Many of these are custody-transfer applications.
Coriolis meters can measure gas flow, but it is not an ideal application for them. Gas is not as dense as
liquids, and Coriolis meters rely on the momentum of the fluid to create the deflection necessary to
measure flow. Even though gas is not the ideal medium for Coriolis meters, they have still had significant
success in measuring gas flow. The AGA-11 Report approves them for custody transfer of natural gas

8. METER RUNS
As per Saudi Aramco spec: SAES-Y-103 :Royalty/Custody Metering Of Hydrocarbon Liquids
As per Exxon Mobil Engineering DS-2009-01 :Specification for the Gas Custody Metering Skid Rev. 3

9. RECOMMENDATION
1. Ultrasonic meters excel in measuring the flow of dry natural gas.
Advantage
• They are widely used for custody transfer of natural gas on pipeline transmission lines, where the pipe
sizes can get quite large.
• The AGA-9 Report approves them for custody transfer of natural gas.
• It is highly recommended that for dry gas and for the bigger pipes size.
• USM is not effected by vibration or noise disturbance in the line.
• High Turndown ratio
Disadvantage
Upstream and downstream distance is 20D and 5D. It can be reduced by 10D and 5D by the use of flow
profiler
Number of streams/ Runs:
• Minimum 2 streams required for the flow transfer of flow.
• The number streams runs are subjected to flow across the pipe and flow meter calculation.

10. RECOMMENDATION
Thank You.