truck unloading air eliminators - pro-kut air eliminator · · 2009-10-01truck unloading air...
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PURPOSE The purpose of an air eliminator is to remove the gas
or air bubbles entrained in the fluid being pumped off
the truck.
Removing the bubbles, or void fraction, improves the
accuracy and performance of the meter.
When the fluid density is used to calculate the water
cut (Net Oil Calculation), removing the void fraction
increases the fluid density, which will increase the
calculated water cut.
Truck Unloading Air Eliminators
Void Fraction
The percentage or volume of product in a
meter that is composed of gas or air
bubbles.
8.2% Void Fraction
Truck Unloading Air Eliminators
Void Fraction
The effect on void fraction in a PD or turbine meter isobvious, an 8.2% void fraction would cause the meterto read 8.2% higher than the actual fluid volume. Thegas or air simply takes up the space in the meter.
8.2% Void Fraction
Truck Unloading Air Eliminators
Sources of Void Fraction
• Fluid being measured at or near bubble point.
• Introduction of air into the fluid, i.e. the truck pump.
• At the start of a load, hoses empty.• Switching tanks or compartments.• The end of a load.
Truck Unloading Air Eliminators
Void Fraction
The effect of void fraction in a Coriolis Meter.
• Causes the drive coil input to increase – shock
absorber effect.
• Reduces the measured density of the fluid.
• Some newer coriolis meters can accurately measure
the mass of the fluid at significant void fraction
levels.
Truck Unloading Air Eliminators
Ways to Reduce Void Fraction
• Increase back pressure on system to prevent
flashing.
• Increase back pressure to reduce the bubble
size.
• Increase pumping pressure to reduce the
amount of air the truck pump can move through
the meter.
• Install an air eliminator to remove the gas and
air from the fluid.
Truck Unloading Air Eliminators
Effect of Void Fraction on Density Measurement
• Reduces the measured Density
Example: Water Density = 1150 kg/m3
5% Void Fraction in Fluid
Indicated Density = (1150 x 0.95) + (1.2 x 0.05)
= 1092.5 + 0.06
= 1092.6 kg/m3
Truck Unloading Air Eliminators
Net Oil Calculation (NOC)
• Calculates Water percentage based on fluid densities
Water % = (Fluid Density – Oil Density) x 100
(Water Density – Oil Density)
Ex: Oil – 830 kg/m3 Water-1150 kg/m3 Fluid 935 kg/m3
Water % = (935 – 830) x 100
(1150 – 830)
= 32.8%
Truck Unloading Air Eliminators
Net Oil Calculation (NOC)
• Effect of 5% Void Fraction
Ex: Oil – 830 kg/m3 Water-1150 kg/m3 Fluid 1092.6
kg/m3
Water % = (1092.6 – 830) x 100 = 82.1%
(1150 – 830)
What you pay for = 17.9% Oil !
Reality = 100% Water !
Truck Unloading Air Eliminators
Net Oil Calculation (NOC)
• Effect of 25% Void Fraction
Ex: Oil – 830 kg/m3 Water-1150 kg/m3 Fluid 862.8 kg/m3
Water % = (862.8 – 830) x 100 = 10.25%
(1150 – 830)
What you pay for = 89.75% Oil !
Reality = 100% Water !
Truck Unloading Air Eliminators
Case #1 - A Tale of Two Meters
• Identical parallel meter runs
• M. M. D Body c/w 9739 transmitters
•One meter run with a Pro-Kut Air Eliminator and back pressure valve, and the other parallel meter run with no air eliminator or back pressure valve.
Truck Unloading Air Eliminators
0
0.2
0.4
0.6
0.8
1
1.2
1.4
0
0.2
0.4
0.6
0.8
1
1.2
1.4
300 400 500 600 700 800
Flo
w R
ate
m3
/min
De
nsi
ty g
m/c
c
Time in Seconds
East Riser Load 1 - 100% Water for Full Load
Density gm/cc Flow Rate m3/min
No data from meter at end of
load. 100% water at sample
point for entire load. Slug flow
for 58 seconds, water air mix,
but no fluid measurement.
58 Second
interval
Without Air Eliminator
Truck Unloading Air Eliminators
0
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0.8
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1.4
0 500 1000 1500 2000
Flo
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ate
m3
/min
.
De
nsi
ty g
m/c
c
Time seconds
East Riser Load 2 - Emulsion Full Load
Density Flow Rate
Tank SwitchRecorded flowvery erratic or at zero
Without Air Eliminator
Truck Unloading Air Eliminators
0
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0.6
0.8
1
1.2
1.4
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0.8
1
1.2
1.4
1000 1020 1040 1060 1080 1100 1120 1140 1160 1180
Flo
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ate
m3
/min
De
nsi
ty g
m/c
c
Time Seconds
East Riser Load 2 – Emulsion at Tank Switch
Density gm/cc
Flow Rate m3/min
1 Minute 40 second tank Switch
Gaps in data during sensor failand slug flow
Without Air Eliminator
Truck Unloading Air Eliminators
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1
0 50 100 150 200 250 300 350
Flo
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ate
m3
/min
De
nsi
ty g
m/c
c
Time Seconds
West Riset Load 1 - End of Condensate Load
Density gm/cc
Flow Rate m3/min
No change in density - no air in fluid during unload
With Air Eliminator
Truck Unloading Air Eliminators
0
0.2
0.4
0.6
0.8
1
1.2
1.4
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1.4
150 650 1150 1650 2150
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m
3
/
m
i
n
D
e
n
s
i
t
y
g
m
/
c
c
Time - Seconds
West Riser - Emulsion Load 2
Density gm/cc
Flow Rate m3/min
Tank Switch
With Air Eliminator
Increasing oil percentage
Truck Unloading Air Eliminators
0
0.2
0.4
0.6
0.8
1
1.2
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0 500 1000 1500 2000 2500
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m
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/
m
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D
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s
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t
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m
3
/
m
i
n
West Riser - Load 3 Emulsion
Density gm/cc
Flow Rate m3/min
Tank Switches
Density very Stable Density dropped for only 6 secondsat end of tank switch
With Air Eliminator
Truck Unloading Air Eliminators
0
0.2
0.4
0.6
0.8
1
1.2
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0.2
0.4
0.6
0.8
1
1.2
1040 1060 1080 1100 1120 1140 1160 1180 1200 1220
Flo
w R
ate
m3
/min
ute
De
nsi
ty g
m/c
c
Time Seconds
West Riser - Full Emulsion Load 3 At Tank Switch
Density gm/cc
Flow Rate m3/min
6 second low density interval
2 minute tank switch interval
With A.E.
Truck Unloading Air Eliminators
Case #2 – Same Meter Run
• First slide – inline horizontal air eliminator
•Second slide – same meter run with Pro-Kut Air Eliminator
• M. M. 3” Elite with 2700 Transmitter
Truck Unloading Air Eliminators
0
10
20
30
40
50
60
70
80
90
100
400
440
480
520
560
600
640
680
720
760
800
0 20 40 60 80 100 120 140 160
Flo
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ate
M3
/hr
De
ns
ity k
g/m
3
Time Seconds
Riser #2 Flow Pattern with 3" In Line Horizontal Air Eliminator
Density
Flow rate
Flow pattern from the meter in 2 second
intervals during the switch from the back to
the lead trailer. Gaps in lines indicates slug
flow and sensor failure due to entrained gas
from truck pump. Air eliminator was cycling
and dumping..
With Low Capacity in line Air Eliminator
Truck Unloading Air Eliminators
0
10
20
30
40
50
60
70
80
90
100
550
570
590
610
630
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710
730
750
0 50 100 150 200 250 300 350 400 450 500
Flo
w R
ate
m3
/hr
De
ns
ity k
g/m
3
Tme Seconds
Riser #2 Flow pattern with 3" Pro-Kut Air Eliminator
Density kg/m3
Flow Rate m3/hr
Flow pattern with vertical air eliminator
during tank switch on back and lead tanks
and end of load.
With Pro-Kut Air Eliminator
Truck Unloading Air Eliminators
Case #3 – Same Meter Run
• First slide – No air eliminator
•Second and third slide – same meter run with Pro-Kut Air Eliminator
•Same truck and driver for both situations
•First load is meter run with no air eliminator – 100% water
•Second load is same meter run with Pro-Kut Air Eliminator with small amount of oil at the top of each tank
• M. M. 3” D body with 9739 Transmitter
Truck Unloading Air Eliminators
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840
960
1080
1200
0.0 200.0 400.0 600.0 800.0 1000.0
Flo
w R
ate
m3
/hr
Den
sit
y k
g/m
3
Time Seconds
Battery 1 Truck Unload Meter Flow Pattern - No Air Eliminator
Density kg/m3
Flow Rate m3/hrTank Switch
Truck Unloading Air Eliminators
-10
0
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0
200
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800
1000
1200
200 400 600 800 1000 1200 1400
Flo
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ate
m3
/min
De
nsi
ty k
g/m
3
Time Seconds
Battery 1 Emulsion Load with Pro-Kut Air Eliminator - Oil At end of Truck Tank Volumes
Density kg/m3
Flow Rate m3/hr
Tank Switch
Truck Unloading Air Eliminators
0
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800
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1050
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1200
880 900 920 940 960 980 1000 1020 1040 1060
Flo
w R
ate
m3
/hr
De
nsi
ty k
g/m
3
Time Seconds
Battery 1 Emulsion Load at Tank Switch
Density kg/m3
Flow Rate m3/hr
Tank Switch
Density dropping as oilat the top of the truck tankstarts to enter meter
With Air Eliminator
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