slurry bubble column hydrodynamics - progress report - novica s. rados department of chemical...

SLURRY BUBBLE COLUMNSLURRY BUBBLE COLUMNHYDRODYNAMICSHYDRODYNAMICS

- Progress Report -

Novica S. RadosNovica S. Rados

Department of Chemical Engineering, CRELWashington University, St. Louis

April 12, 2001

CHEMICAL REACTION ENGINEERING LABORATORY

Motivation and ObjectivesMotivation and Objectives

• There is a lack of experimental data on slurry bubble columns operatedat these conditions.

• Develop a new CARPT calibration apparatus and scanning procedurethat can be used for thick wall high pressure metal vessels.

• Slurry bubble columns are frequently used type of chemical reactors.They mostly operate in churn turbulent regime and at high pressure.

• Develop a more robust CARPT tracer particle position reconstructionalgorithm that can more accurately resolve arches and other “imperfections”of the CARPT calibration (count vs. distance) curves.

• Acquire CARPT experimental data of a slurry bubble column operatedat a wide range of gas velocities and pressures.


CARPT Calibration DeviceCARPT Calibration Device

tracer particleholding rod ass.

needle bearing

high pressure seals

PVDF guides

sprocket

tripod

rod

lead screw

theta dir. stepper motor

axial dir. stepper motor

8:1 gear box


CARPT CalibrationCARPT Calibration

Calibration yields count vs. distance curvecounts = f (distance, solid angle, wall path,

medium)

dE/d vs

0

0.2

0.4

0.6

0.8

1

1.2

1.4

0 100 200 300 400 500 600 700 800 900 1000

in mV

dE/d

det_9

Det_A

Det_K

Det_L

Det_M

Det_N

Det_O

Det_P

Det_Q

Det_R

0.89 M ev1.12 M ev

dE/d vs

0

0.2

0.4

0.6

0.8

1

1.2

1.4

0 100 200 300 400 500 600 700 800 900 1000

in mV

dE/d

det_9

Det_A

Det_K

Det_L

Det_M

Det_N

Det_O

Det_P

Det_Q

Det_R

0.89 M ev1.12 M ev

thresholdBuild-up problems

wall path

detectorcrystal

solidangle

ComptonScattering Photo peaks

Threshold = 45 mV


Spectrum StabilitySpectrum Stability

Acquisition of the photo peak fraction of the spectrum using a

high threshold

Stability of the Spectrum ?Spectrum f (source

strength)

Gupta:Spectrum = f (distance)

Rammohan:Spectrum = f (time)

0

0.1

0.2

0.3

0.4

0.5

550 600 650 700 750Energy, mV

Inte

nsi

ty

Det. 1 - airDet. 16 - airDet. 1 - waterDet. 16 - water

&Spectrum shifted slightly only when:

- distance was changed for more than 2 ft.- order of magnitude weaker particle was used

- gain wasn’t tuned over several daysrequired nearly ideal conditions


Calibration Calibration CurveCurve

Detector alignment and pile-up problems

Detectors well alignedand further away

0

5

10

15

20

25

30

35

40

0 100 200 300 400 500 600 700 800Distance, cm

Co

un

ts

dz = 0 cm

dz = -7.62 cm

dz = 8.50 cm

Threshold = 600 mV

G-L: Ug=30cm/s

Det #7


Pile Up LimitationsPile Up LimitationsPile up: Detectors are unable to count all incoming photons

0

500

1000

1500

2000

2500

3000

3500

-180-160-140-120-100-80-60-40-200 20 40 60 80 100120140160180

Theta, degrees

Co

un

ts

0

50

100

150

200

250

300

350

-18

0

-16

0

-14

0

-12

0

-10

0

-80

-60

-40

-20

0 20

40

60

80

10

0

12

0

14

0

16

0

18

0

Theta, degreesC

ou

nts

Detectors too close !

+ Distorted Spectrum +

Detectors further away !

+ Well Shaped Spectrum +

When using the photo peakfraction of the spectrum

CMax < 1000

detectorcrystal

8

12

16

20

24

28

0 100 200 300 400 500 600 700Counts

Dis

tan

ce

, cm

272 deg.

267 deg.


Laser Detector Laser Detector AlignmentAlignment- Posts not firm enough => middle detectors can vibrate / move- Angles between detectors not 45o => mismatched particle/detector positionsDeg. 45-1 30-1 8-1 14-1 30w35-130d300-130cs-1 30pph-1 45-4 30-4 8-10 29pph-10Mean StDev Position

1 -2 2 -2 0 -2 2 0.5 3 -1.5 -1 -2 -0.5 0.02 44.5 49 49 46.5 46.5 46 46 50 46 47 43 46 46.9 1.72 46.93 -2 0.5 0.5 0 -2 -1 -2 0 -3 -1 -3 -2 47.9 1.12 -1.04 43 44 44 44 44 45 43.5 46.5 43 45 43 45 45.4 1.11 44.45 -3 0.5 -1 -1 -2 -2 -3 1 -2 -1 -3.5 -2 45.8 0.97 -1.46 43 44 43.5 43.5 43.5 43.5 43.5 43.5 42 44 42 44.5 45.0 1.16 43.67 -5 -1 -3 -3 -3 -4 -3.5 -3.5 -3 -1.5 -3.5 -3.5 46.5 1.02 -2.98 42 45.5 44 44 43 43 42 42 43 45 44 44.5 46.6 0.74 43.79 88 91 89 89 89 89 89 89 90 91 90 91 46.1 0.67 89.810 134.5 137 136 136 135 135 134 136 136 136 136 136 46.0 0.72 135.811 91 91 90.5 90.5 90.5 91 87.5 91 91 91 90 92 45.0 0.88 90.812 136 137 136 136 136 136 135 136 136 135 135.5 137.5 45.4 0.79 136.213 89 90.5 91 91 91 91 90 91 92 91 89 90.5 45.4 1.02 90.814 136 138 138 137 137 136.5 137 139 138 138 133.5 136 46.4 0.95 137.215 91 94 91 91 90 92 92 95 91 91 89 92 45.4 1.24 91.8A 179 183 180 180 178.5 182.5 181 184 180 181 180 181 89.3 0.80 181.1K 224 229 228 229 226.5 226.5 226.5 228 226 226.5 223 225 45.7 1.78 226.8L 179 181 181 181 179 180 179 181 182 182 178.5 179.5 46.3 1.41 180.5M 224 226 226 225 224 224.5 224 227 224 226 223.5 224.5 44.6 0.94 225.1N 179 183 180.5 180.5 179 181 180.5 183 181 182 179 181.5 44.0 0.83 181.1O 222 228 224.5 226 224 223 223 224 225.5 226 222 224 43.5 1.32 224.6P 177.5 181 179 179 179 178 177 178 179.5 179.5 179 180 45.5 1.16 179.1Q 222 226 223 223 223 223 223 223 223 224 223 223.5 44.4 0.70 223.5R 264 267.5 266 267 266 266 265 267 267 268 265 266 42.9 0.89 266.4S 309 313 312 312 311 311 311 311 312 312 309 311 45.0 0.66 311.4T 266 270 269.5 270 268.5 268 267.5 271 268 268 267 268 42.7 1.03 268.7U 311 313 312 313 312 312 312 314 312.5 312.5 311 311.5 43.8 0.75 312.5V 268 270 270 272 269 270 269 271 268 269 267 268 43.0 0.90 269.5W 311 317 315 315 313.5 313 313.5 314 313 314 309 310 43.9 1.43 313.4X 267 272.5 269 272 269 271 270.5 272 268.5 268.5 267.5 269 43.5 1.55 269.9

Difference

All detectors arewithin 5 degrees


CARPT - Error AnalysisCARPT - Error Analysis

bC

ad

CC C

C

C

C

abd

b

C

Cb

d

d

C

d

dNS

C

dbd

=> =>

=>

3

1i

2Dji

2j )xx(d

d3

1x

assumed power law dependency

error in counts = std. distribution

weighing function

signal to noise ratio

exact error dependson the algorithm andthe number of useddetectors

a 106 b 0.38Cm dm, cm VarC %C dd, mm %d dx, mm

10 44.19 3.16 31.62 53.10 120.17 30.720 33.96 4.47 22.36 28.85 84.97 16.750 23.97 7.07 14.14 12.88 53.74 7.4

100 18.42 10.00 10.00 7.00 38.00 4.0500 9.99 22.36 4.47 1.70 16.99 1.0

1000 7.68 31.62 3.16 0.92 12.02 0.53000 5.06 54.77 1.83 0.35 6.94 0.2

C cm,d C 100*C

Cd 100*

d

dx

d = 105.55C-0.3779

0

5

10

15

20

25

30

0 500 1000 1500 2000 2500 3000 3500Counts

dist

ance

, cm

G-L: Ug=30cm/s

Det #3

1

10

100

10 100 1000 10000

f1,RC source strength,

sampling time


Particle Position Reconstruction Particle Position Reconstruction AlgorithmAlgorithm

0

5

10

15

20

25

30

35

40

0 100 200 300 400 500 600 700Counts

Dis

tan

ce

, cm

Rados

1. Find distance using beta beta spline fitspline fit of the

calibration curve. Determine particle

location using least square

approach.2. Find distance using Find distance using

powerpower law fit of the several law fit of the several surrounding calib. surrounding calib.

points.points. Determine particle


approach.

Step 1.

-10 -5 0 5 10-10

-8

-6

-4

-2

0

2

4

6

8

10

x,cm

y,cm

-10 -5 0 5 10-10

-8

-6

-4

-2

0

2

4

6

8

10

x,cmy,

cm

Disadvantages

- Only one z level considered- Far points on the same level unnecessarily considered

Step 2. Step 2.

improvement

Degaleesan

1. Find distance using qubicqubic

spline fitspline fit of the calibration

curve. Determine particle


approach.2. Find distance using2. Find distance using quadratic fit of all quadratic fit of all

calib.calib. points at a single points at a single

level.level. Determine particle


approach.


Local Power Law FittingLocal Power Law Fittingy = 103.9x-0.3792

R2 = 0.9592

7

9

11

13

15

100 300 500 700 900

y = 125.01x-0.4062

R2 = 0.9844

10

12

14

16

18

100 200 300 400

y = 115.04x-0.401

R2 = 0.9733

12

14

16

18

20

100 200 300

y = 73.276x-0.2562

R2 = 0.8839

35

37

39

41

43

45

7 8 9 10 11 12 13

Counts

Dis

tan

ce, c

m


Position ReconstructionPosition Reconstruction

Rados’ method: more spurious points (using less det.) better centered islands

comparable size of the islands to Degaleesan

G-LUg=30cm/s


Position ReconstructionPosition Reconstruction

off center ~ 4 (9) mm off center < 3 mmr ~ 7.5 (10) mm r ~ 7.5 mm < 15 mm < 13 (18) mmz ~ 10 (30) mm z < 5 mm

G-LUg=30cm/s


Calibration Curve - G-L Calibration Curve - G-L Beta-Spline FittingBeta-Spline Fitting

Ong: G-LUg=30cm/s

0

20

40

60

80

100

120

140

160

0 200 400 600 800

0

10

20

30

40

0 50 100 150 200 250 300

Detector #30 (X)

Dis

tan

ce, c

m

Counts


Position Reconstruction - Position Reconstruction - G-LG-L

off center < 6 mm off center < 2 mmr ~ 6 mm r < 5 mm < 9 mm < 5 mmz ~ 10 mm z < 3 (5) mm

Ong: G-LUg=30cm/s

-10 -5 0 5 10-10

-8

-6

-4

-2

0

2

4

6

8

10

x,cmy,

cm

Rados - 20 weighed det.

-10 -5 0 5 10-10

-8

-6

-4

-2

0

2

4

6

8

10

x,cm

y,cm

Degaleesan - 30 weighed det.


Calibration Curve - SlurryCalibration Curve - Slurry

0

5

10

15

20

25

30

35

40

0 100 200 300 400 500 600 700Counts

Dis

tan

ce

, cm

0

5

10

15

20

25

30

35

40

0 100 200 300 400 500 600 700Counts

Dis

tan

ce

, cm

ring 3: r = 7.62 cm

ring 0, 1, 2:r = 0, 2.54, 5.08 cm

0

5

10

15

20

25

30

35

40

0 100 200 300 400 500 600 700Counts

Dis

tan

ce

, cm

Arches are caused by the wall and solids (wall path) (medium)

G-L-SUg=45cm/s

Detector #30 (X)


Position Reconstruction - SlurryPosition Reconstruction - Slurry

off center ~ 6 (20) mm off center < 3.5 (6) mmr < 10 (20) mm r < 7 mm ~ 10 mm < 7 (10) mmz ~ 10 (30) mm z ~ 3 (10) mm

G-L-SUg=45cm/s


CARPT Slurry ExperimentsCARPT Slurry Experiments20-Jan 45-1c Total of 12 experiments was completed in 58 days !21-Jan 45-1r22-Jan 45-1r23-Jan Tripoid redesigned24-Jan | 30-1r25-Jan | 30-1r26-Jan | 8-1r27-Jan | 8-1r 14-1r28-Jan | 14-1r 30w-1r w - 35 wt.% loading29-Jan V 30w-1r30-Jan31-Jan 30-1c1-Feb 30-1c2-Feb 8-1c 14-1c3-Feb4-Feb 300 m tracer particle selected5-Feb 30w-1c6-Feb 30d-1c d - 300 m tracer particle7-Feb 30d-1r8-Feb 30d-1r9-Feb

10-Feb * 150 m tracer particle changed *11-Feb 30cs-1c cs - cross sparger12-Feb 30cs-1r13-Feb 30cs-1r14-Feb Detectors 15 and Q replaced15-Feb 30h-1c h - 1% OA PP sparger16-Feb 30h-1r17-Feb 30h-1r18-Feb

Modifications

1. Tripoid redesigned

2. Det. changed3. Plate

redesigned4. Det. moved

closer5. Gear box added6. Rod guides

added

Exp. Ug,cm/s P,bar Distrib. Note1 8 1 PPL2 14 1 PPL3 30 1 PPL4 45 1 PPL5 30 1 PPL 35wt.%6 30 1 PPL 300um7 30 1 CS8 30 1 PPH9 30 4 PPL10 45 4 PPL11 8 10 PPL12 30 10 PPH


CARPT Slurry ExperimentsCARPT Slurry Experiments19-Feb Device plate redesigned, device centered20-Feb |21-Feb |22-Feb |23-Feb |24-Feb |25-Feb V26-Feb Detectors moved closer to the column (2.5 ->1.75 in.)27-Feb 45-4c28-Feb 45-4r1-Mar 45-4r2-Mar * 150 m tracer particle changed * 30-4c3-Mar 30-4r4-Mar 30-4r5-Mar6-Mar Reducing gear box selected and ordered7-Mar |8-Mar Rod guides installed9-Mar |10-Mar |11-Mar V12-Mar Reducing gear box installed13-Mar V14-Mar 8-10c15-Mar 8-10r16-Mar 8-10r17-Mar 29h-10c18-Mar 29h-10r19-Mar 29h-10r


Conclusion and Future Conclusion and Future WorkWork

• Developed automated CARPT calibration device, detector alignment, photo peak scanning procedures and position reconstruction algorithm enable acquisition of CARPT experiments even in thick wall high pressure metal vessels.

• Process the acquired experimental data.- reconstruct the tracer particle (x,y,z) positions- filter the positions- process the velocities- process the “turbulent parameters” (stresses & TKE)- process the eddy diffusivites

• Finish the DP experiments and finish processing holdup profiles.

slurry bubble column hydrodynamics - progress report - novica s. rados department of chemical...

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