computational t-junction separator fluid dynamic study on for liquid-gas separation introduction the...
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COMPUTATIONAL
T-JUNCTION SEPARATOR
FLUID DYNAMIC STUDY ON
FOR LIQUID-GAS SEPARATION
INTRODUCTIONThe separations of liquid-gas flows are performed in large vessels under the effect of gravity. The application of a simple defined partial phase separator(T-junction) would produce two streams, one rich in gas and the other rich in liquid. This would be beneficial for offshore oil platforms where safety, space, weight and cost are highly emphasized.
OBJECTIVES Apply knowledge of flow split of liquid-gas flows at T-
junction to develop a novel/improved partial phase separator.
Apply numerical study to simulate the separation of liquid–gas and analyze the separation efficiency of existing T-junction designs to create a fluid flow model.
Apply fluid model and simulate liquid-gas separation on proposed T-junction design to analyze separation efficiency.
PROBLEM STATEMENTUnequal separation (maldistribution) of liquid-gas causes the gas scrubber to unable to isolate the liquid and gas due to large amount of wet gas channeled into it.
SCOPE OF STUDY Horizontal liquid-gas flow in horizontal T-junction
configuration with 90 degree vertical side arm.
Diverging T-junction of 1 inlet and 2 outlets with no internal attachments.
METHODOLOGY
1. Research on horizontal T-
junction experiment or
simulation study
2. Build fluid model based on
selected experiment or
simulation settings
3. Validate fluid model with the
selected experiment or
simulation result
6. Validate /analyze
separation efficiency with
other published work
5. Analyze liquid-gas
separation with alteration of fluid model
4. Apply fluid model to
proposed T-junction design
RESULTS & DISCUSSION
Selected work for fluid model development:
Experiment: Azzopardi et. al. (2000)
Simulation: Cavalcanti et. al. (2011)
Proposed T-junction design
Diameter(cm)
Length(cm)
INLET 10 55
OUTLETUP
10 50
OUTLET DOWN
10 50
i. Fluid model validation
ii. Proposed T-junction design with base fluid model
The fluid model from the simulation work is selected to study the liquid-gas separation on the proposed T-junction based on:
Less % error in output data
Less assumptions made during Cavalcanti’s simulation work
Cavalcanti’s T-junction Proposed T-junction
Outlet 1
(horizontal)
Outlet 2
(vertical)
Outlet
downward
Outlet upward
Water 0.1845 0.05110 0.117425 0.118606
Gas 0.0001154 0.0001483 0.000131024 0.000132303
Oil 0.11826 0.10584 0.111429 0.112675
The outlet data is based on base model fluid without the effect of gravity.
The mass flow rates at the outlets are almost equally divided with the outlet upward having slightly higher intake values for all 3 fluids.
iii. Proposed T-junction design with modified fluid model
Water Gas Oil
Water Gas Oil
Cavalcanti’s T-junction Proposed T-junction
Outlet 1
(horizontal)
Outlet 2
(vertical)
Outlet
downward
Outlet upward
Water 0.1845 0.05110 0.305239 0
Gas 0.0001154 0.0001483 8.208 E-0.08 0
Oil 0.11826 0.10584 0.395789 0
The outlet data is based on base model fluid with the effect of gravity.
Outlet upward produce zero value due to the low superficial velocity of fluid at the inlet.
iv. Proposed T-junction design with experiment work (Baker, 2003)
Proposed T-junction
Inlet
(kg/s)
Outlet
downward
(%)
Outlet
upward
(%)
Water 2.183 46.5 53.5
Gas 0.216 48.6 51.4
Oil 2.076 47.9 52.1
The outlet data is based on base model fluid with the effect of gravity and increased fluid velocity.
A similar split (almost equal) was obtained during separation at the T-junction with outlet upward having higher intake value.
CONCLUSION
RECOMMENDATION
The proposed T-junction design is capable to split liquid-gas fluid into liquid rich stream and gas rich stream at respective outlets with the condition gravity effect and increased velocity are taken into account.
Simulate liquid-gas separation with different fluid superficial velocity to find the margin/boundary at which the velocity is applicable for the applied diameter size, and vice-versa by simulating separation with different diameter for applied fluid superficial velocity.
Create correlation between diameter size and fluid superficial velocity for proposed T-junction design.
Name
ID
Programme
Supervisor
: Dinesh A/L Balakrishnan
: 12561
: Petroleum Engineering
: Miss Raja Rajeswary Suppiah
INFORMATION
Water Gas Oil