Agreement of Sand Sl by pat67327

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									     EFFECT OF SAND DISTRIBUTION ON
  EROSION IN ANNULAR THREE- PHASE FLOW

Quamrul H. Mazumder, Siamack A. Shirazi, and
             Brenton S. McLaury


  Erosion/Corrosion Research Center (E/CRC)
     Mechanical Engineering Department
           The University of Tulsa
                April 1, 2004
                     Overview

   Introduction
   Objective
   Background
   Mechanistic Model Development
   Experimental Investigation of Erosion
   Experimental Investigation of Sand Distribution
   Summary and Conclusion
               Introduction

Erosion in fluid handling equipment is a major
problem in several industries due to entrained
solid particles in the fluid
                  Introduction
 Erosion is a process by which material is removed
 from a solid surface due to mechanical effects
 such as impingement of solid particles on a
 surface
 Erosion can cause severe damage to the piping
 and equipment wall, resulting in loss of equipment
 and production downtime
 Erosion phenomenon is complicated due to a wide
 range of parameters such as fluid properties, solid
 particle size and distribution in flow, wall
 materials, geometry, etc.
               Introduction
 Elbows and Plugged Tees are geometries
 that are used to redirect fluid and are
 susceptible to erosion damage.
            Introduction (Continued)
 Prediction of erosion in multiphase flow is a
  complex problem due to lack of understanding of
  the particle impact velocity that causes erosion
 Particle impact velocity depends upon the
  geometry, carrying fluid velocity, flow pattern,
  particle size and distribution
 The complexity of erosion prediction increases
  significantly for three phase flow (gas, liquid and
  solid)
 Among different flow patterns, severe erosion
  damage occurs in annular flow with high gas and
  low liquid velocities
                   Objectives

 The Objective of this work is to investigate
  erosion behavior in behavior in annular
  three-phase flow ( solid/ liquid/ gas)
 Investigate solid particle (sand) distribution
  and its effect on erosion in annular flow.
 Investigate erosion behavior in horizontal
  and vertical flow.
 Develop a mechanistic erosion prediction
  model to predict erosion in annular flow
                  Background
 Most of the currently available erosion
  prediction models are based on empirical data
 Accuracy of these models are limited to
  certain flow conditions and are not general
 Erosion Corrosion Research Center (E/CRC) of
  The University of Tulsa developed a semi-
  mechanistic model based on empirical data
  and CFD model to predict erosion
 The model uses characteristic particle impact
  velocity to calculate erosion
               Background (continued)
The E/CRC model for calculating maximum penetration
rate for an elbow or tee can be written as
                                             1.73
                                    WV
                  h  FMFSFPFr / D          L
                                                 2
                                   (D / D )   0

  –h = penetration rate in mm/year or mpy
  –FM = empirical constant related to material hardness
  –FS = empirical sand sharpness factor
  –FP = penetration factor for steel based in 1” pipe diameter, (m/kg)
  –Fr/D = penetration factor for long radius elbows
  –W = sand production rate, (kg/s)
  –VL = characteristic particle impact velocity, (m/s)
  –D = pipe diameter, (in mm)
  –D0 = 25.4 mm
            Background (continued)
  For a given geometry, material, sand sharpness,
  sand rate, the erosion prediction equation can
  be written as
                     h  KVL
                               1.73



Where VL is the characteristic particle impact velocity.

• A method for calculating the characteristic
impact velocity was developed by using a simple
model for stagnation layer in pipe geometry
• The stagnation zone is a region where the
particles must travel and penetrate to strike the
pipe wall to cause erosion
             Background (E/CRC Model)
Stagnation                  Equivalent Stagnation Length
     Zone


                                              L

                           Particle Initial
                           Position

                Tee
Stagnation
     Zone                  vo

                                    x



               Elbow
                    Present Work

 We are proposing a new Mechanistic Model to
  calculate characteristic initial particle velocity Vo.
 The mechanistic model velocity calculation is
  based on theory of two phase flow.
 The mechanistic model will use flow velocities
  and sand distribution in the flow
 The mechanistic model attempts to shed more
  light on the physics of erosion phenomenon
 Mechanistic model is expected to be more
  reliable and general compared to the semi-
  empirical model
 Schematic of Annular Flow
VFilm      Vdroplet
                      Annular
                      Liquid Film
                      Thickness, *

                      Sand
                      Particles in
                      the film


                      Entrained Sand
                      Particles and Liquid
                      Droplets in The Gas
                      Core Region




        DCore
     Mechanistic Model Development
The proposed mechanistic model for sand particle
initial characteristic velocity is:
Vo = (Mass fraction of sand in film x Vfilm) +
                   (Mass fraction of sand in gas core x Vd)

Assuming sand concentration (mass of sand/ mass of
liquid) is uniform in annular flow
Vo = (Mass fraction of liquid in film x Vfilm) +
                   (Mass fraction of liquid in gas core x Vd)

 Vo = (1-E)Vfilm + E x Vd
Where, E = Fraction of liquid entrained in the gas core
            Vfilm = Average liquid film velocity (ft/sec)
            Vd = Average liquid droplet velocity (ft/sec)
         Liquid Film and Droplet Velocity
                   Calculations

 Vfilm and entrainment fraction were calculated
  based on two phase flow model developed by
  Ansari (1989) at TUFFP
 A simplified method for calculating droplet
  velocity was developed as the effect of sand
  particles in the droplets are higher on erosion
 Calculated mean centerline droplet velocities
  were compared to Dukler (1994) droplet velocity
  measurements and showed good agreement
                                     Comparison of Calculated and
                                     Experimental Droplet Velocities
                           45
                                       Re(Liq.) = 750 (Calculated)
                                       Re(Liq.) = 750 (Dukler)
Droplet Velocity (m/sec)




                                       Re(Liq.)=3000 (Calculated)
                           35          Re(Liq.)=3000 (Dukler)




                           25




                           15
                                15               20                  25             30   35
                                                    Superficial Gas Velocity ( m/sec)
Comparison of Measured Erosion with E/CRC
  Semi-empirical and Mechanistic Models
 Mechanistic model was compared with erosion
 data reported by Salama (1998) and Bourgoyne
 (1989)
 Bourgoyne erosion data was for high gas
 velocities and low liquid rates with 350 micron
 sand
 The above erosion data reported by Salama were
 gathered at DNV and AEA for
     • One and two-inch flow loops
     • Carbon Steel and Stainless Steel
     • Annular, slug and bubble flows
     • Two different sand sizes (150 and 350 microns)
          Comparison of Measured Erosion with
            New Mechanistic Model Predictions
                                                           Mech.Model
 Superficial Superficial Elbow         Sand Measured        Predicted
  Liq. Vel.      Gas Vel.      Dia.     Size    Erosion       Erosion
V SL (m/sec) V SG (m/sec) (mm) (Micron) (mm/kg)              (mm/kg)    Note
      1             30          49      150    5.52E-04     8.93E-04      1
     0.5            30          49      150    2.46E-03     1.45E-03      1
     5.8            20          49      150    5.19E-05     5.48E-05      1
     3.1            20          49      150    6.93E-05     1.20E-04      1
      5             15          49      150    6.38E-05     1.11E-05      1
      1             15          49      150    1.47E-04     1.09E-04      1
     1.5           14.4        26.5     250    2.30E-04     5.38E-04      2
     1.5           14.6        26.5     250    4.20E-04     5.58E-04      2
     2.1            34         26.5     250    2.83E-03     3.79E-03      2
      1             35         26.5     250    6.56E-03     5.78E-03      2
     0.5           34.3        26.5     250    7.20E-03     6.92E-03      2
     0.7            37         26.5     250    8.03E-03     7.38E-03      2
     0.5           38.5        26.5     250    8.03E-03     8.84E-03      2
     1.5            44         26.5     250    1.05E-02     8.23E-03      2
     0.6            51         26.5     250    1.34E-02     1.52E-02      2
     0.7            52         26.5     250    1.33E-02     1.51E-02      2
(1) Fluid: air/ water at 2 bar, Material: Carbon Steel (Brinell Hardness 160)
(2) Fluid: nitrogen/water at 7 bars, Material: Duplex Stainless Steel
  Experimental Investigation of Erosion

 Erosion experiments were conducted at
 E/CRC using two different one-inch multiphase
 flow loops with Lf / D = 70 and Lf / D = 160
 One-inch elbow specimen was used during the
 erosion experiment
 Examined the effects of variables on erosion
   –Liquid and gas velocities
   –Inclination angle (Horizontal, Vertical)
         E/CRC Multiphase Flow Loop
                       (One inch Lf/D  70)


  Test Cell
  (Vertical)
                                                    Air to
                                                 Compressors



                  Slurry
                   Tank                  Drain
                  (Liq+Sand)
5.5 ft

                                                       Air From
                                                      Compressors
                  6.2 ft
                           Mixing Zone
Test Cell Horizontal
E/CRC Multiphase Flow Loop (One inch Lf/D  160)

                               Filter                Cyclone
                                                     Separator


                                 Test Cell-Ver

                 Slurry Tank
                                                         13 ft

   Water Tank
                               Test Cell- Hor    Drain

                                   13.3 ft


                           Flowmeter


                Compressors
           Test Cell




Erosion
Specimen
             Measured Horizontal and Vertical Erosion at
                  Vsg=30.48 m/sec, Vsl=0.30 m/sec
                       1.3
                                   L/ D   =7 0 : V e rt ic a l
                                   L/ D   =7 0 : H o rizo nt a l
Normalized Mass Loss



                       1.0         L/ D   =16 0 : V e rt ic a l
                                   L/ D   =16 0 : H o rizo nt a l

                       0.8
                                              Vertical

                       0.5                         FLOW



                                     Horiz
                       0.3

                       0.0
                             0.0             3.0          6.0       9.0   12.0   15.0

                                             Sand Throughput (Kilograms)
 Comparison of Horizontal and Vertical Erosion
                              Vsg=22.86 m/sec, Vsl = 0.30 m/sec, Lf/D=160
Normalized Mass Loss



                       1.0             Horizontal
                                      Vertical
                       0.8
                                                                             Vertical
                                                                             Vertical
                       0.5                                                       FLOW
                                                                                 FLOW



                       0.3                                           Horiz
                                                                    Horiz


                       0.0
                             0.0    4.0      8.0    12.0     16.0      20.0             24.0
                                      Sand Throughput (Kilograms)
   Sand Distribution in Multiphase Flow
                                                  Sand
                                                 Entrainment
                      Liquid droplets


                           Liquid
                           Film




                         Sand
                         Particles
      Vertical flow                     Horizontal Flow

More sand particles in horizontal annular liquid film
Intrusive Probe Used for Sand Sampling
            Sand and Liquid Distribution in Vertical Pipe
Percent Sand and Water       Vsg=30.48 m/sec, Vsl = 0.30 m/sec, Lf/D=160

                         6            M easured liquid/to tal liquid thro ughput
                                      M easured sand/to tal sand thro ughput
                         5

                         4
                         3
                         2

                         1
                         0
                                  1          2           3           4             5
                                                 Probe Location
Sand and Liquid Distribution in Horizontal Pipe
                    Vsg=30.48 m/sec, Vsl = 0.30 m/sec, Lf/D=160

                    5                             Measured sand/total
                                                  sand throughput
                    4
   Probe location



                                                  Measured liquid/total
                                                  liquid throughput
                    3

                    2

                    1

                        0      1         2         3         4            5

                                   Percent Sand and Water
Sand and Liquid Distribution in Vertical Pipe
                          Vsg= 22.86 m/sec, Vsl = 0.30 m/sec, Lf/D=160

                          4
 Percent Sand and Water
                                     M easured liquid/to tal liquid thro ughput
                                     M easured sand/to tal sand thro ughput

                          3


                          2


                          1


                          0
                                 1            2           3            4          5
                                              Probe Location
Sand and Liquid Distribution in Horizontal Pipe
                    Vsg= 22.86 m/sec, Vsl = 0.30 m/sec, Lf/D=160

                    5              M easured sand/to tal sand thro ughput
                                   M easured liquid/to tal liquid thro ughput
   Probe location



                    4

                    3

                    2

                    1

                        0        2        4      6                              8
                               Percent Sand and Water
                       Measured Horizontal and Vertical Erosion at
                            Vsg=30.48 m/sec, Vsl=0.30 m/sec
                        1.3




                                                                     Percent Sand and Water
                                                                                              6                            M easured liquid/to tal liquid thro ughput
                                                                                                                           M easured sand/to tal sand thro ughput
                                                                                              5
                                    L/ D   =7 0 : V e rt ic a l
                                                                                              4
                                    L/ D   =7 0 : H o rizo nt a l
Normalized Mass Loss



                                                                                              3
                        1.0         L/ D   =16 0 : V e rt ic a l                              2
                                    L/ D   =16 0 : H o rizo nt a l                            1
                                                                                              0
                        0.8                                                                                            1            2           3
                                                                                                                                        Probe Location
                                                                                                                                                           4            5




                                                                                                               5                                      Measured sand/total
                        0.5                                                                                    4
                                                                                                                                                      sand throughput




                                                                                              Probe location
                                                                                                                                                      Measured liquid/total
                                                                                                                                                      liquid throughput
                                                                                                               3

                                                                                                               2

                        0.3                                                                                    1

                                                                                                                   0            1           2          3           4          5

                                                                                                                                    Percent Sand and Water
                        0.0
                              0.0            3.0           6.0       9.0                                                                 12.0                           15.0

                                             Sand Throughput (Kilograms)
 Comparison of Horizontal and Vertical Erosion
                              Vsg=22.86 m/sec, Vsl = 0.30 m/sec, Lf/D=160
                                                                                       4




                                                            Percent Sand and Water
                                                                                                       M easured liquid/to tal liquid thro ughput
                                                                                                       M easured sand/to tal sand thro ughput

                                                                                       3
Normalized Mass Loss



                       1.0             Horizontal                                      2

                                                                                       1
                                      Vertical                                         0
                       0.8                                                                         1            2     3      4
                                                                                                                Probe Location                      5



                                                                                           5                    M easured sand/to tal sand thro ughput
                                                                                                                M easured liquid/to tal liquid thro ughput
                       0.5




                                                                      Probe location
                                                                                           4

                                                                                           3

                                                                                           2
                       0.3                                                                 1

                                                                                               0            2        4      6                                8
                                                                                                          Percent Sand and Water
                       0.0
                             0.0    4.0      8.0    12.0                     16.0                                    20.0                           24.0
                                      Sand Throughput (Kilograms)
          Summary and Conclusions

 Mechanistic erosion prediction model has been
 developed for annular three- phase flow
 Mechanistic model predictions showed good
 agreement with experimental results in the
 literature
 Different erosion rates were observed Between
 Lf /D=70 and Lf /D=160 flow loops
 Higher erosion was observed in the vertical
 specimen compared to the horizontal specimen.

								
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