Flow dynamics study of catalyst powder in CCU for ......2017/04/25  · S1 450 2 9 13 S2 1650 4 10 11 S3 2850 3 8 12 Inlet Detector Outlet Detector Primary RC1: Blue RC2: Green RC3:

Flow dynamics study of catalyst powder in CCU for troubleshooting

Board of Radiation & Isotope Technology,

Deptt. of Atomic Energy, Govt. of India,

Vashi Complex, Navi Mumbai, INDIA

Vivek Yelgaonkar, Gaurav Agrahari, Dhakar Vikrant, Rao Prasanna, Pathak B.K.

Problem:

Catalyst powder was observed

in the fractionator tower which is not at all desired

Scheme:

1. Gamma scanning of

each set of primary and

secondary cyclones and

compare the densities

obtained at various

locations

2. Radiotracer study to

understand flow dynamics

of catalyst powder

S3P3

S2

P2S1

P1

0 20 40 60 80 100 120 140 160 180 200

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igh

t in

mm

count rate

CCU line1

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CCU line2

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CCU L3

S2 S3 S1

0 50 100 150 200 250

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t in

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CCU L3

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CCU line2h

eig

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in m

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count rate

CCU line1

Handling of radiotracer at site

Catalyst Powder (irradiated)

Steam

(~10Kg/cm2) Injection of Radiotracer

in to riser

Radiotracer Study

D2,3,4

D11,12,13

D8,9,10

D16,6,7

Secondarynumber

Secondaryangle

Detector placed at vortex breaker

Detector placed at secondary body

Detector placed at outlet of plenum chamber

S1 450 2 9 13

S2 1650 4 10 11

S3 2850 3 8 12

Inlet Detector

Outlet Detector

Primary

RC1: Blue

RC2: Green

RC3: Red

Vortex Breaker

S1 (450): Blue

S2 (1650): Red

S3 (2850): Green

Secondary Body

S1 (450): Blue

S2 (1650): Red

S3 (2850): Green

Plenum Chamber

S1 (450): Blue

S2 (1650): Red

S3 (2850): Green

Plenum Chamber

S2 (1650): Red

Secondarynumber

Secondaryangle

Area under tracer curve

Percentage of powder travelledthrough

Mean residence time(seconds)

S1 450 17532 35 1.58

S2 1650 6483 13 1.56

S3 2850 26841 52 2.18

Secondary Body

S1

S2

S3

Secondarynumber

Secondaryangle

Area under tracer curve

Percentage of powder travelledthrough

Mean residence time(seconds)

S1 450 29799 42 2.34

S2 1650 2517 4 1.94

S3 2850 38593 54 2.28

Vortex breaker

S1

S2

S3

Outlet of plenum Chamber

Secondarynumber

Secondaryangle

Area under tracer curve

Percentage of powder travelledthrough

Mean residence time(seconds)

S1 450 80164 17.5 77.5

S2 1650 333205 73 192

S3 2850 43712 9.5 6.18

S1

S2

S3

Outlet of plenum Chamber

S2 (1650): Red

Complete powder release from this secondary plenum requires 192 seconds

Conclusions Gamma Scanning • S2 - Filled with powder.

• S1 - Uneven density distribution isobserved indicating disturbances incatalyst powder flow.

• S3 – Normal catalyst flowRadiotracer Studies• Since secondary cyclone S2 is filled with powder, quantity of

radiotracer catalyst powder received is least (13%).

• The same trend is reflected in vortex breaker where only 4% ofthe powder escapes.

• Outlet of S2 to plenum chamber slowly releases the radiotracercatalyst powder(in 192s). Quantity of powder released throughthis outlet is very high (73%) which could be responsible forcatalyst powder carrying over towards fractionator.

• Secondary cyclone S1 also shows partial filling of catalystpowder. The quantity of catalyst powder received is 35%.

• The vortex breaker receives 42%.

• Release of radiotracer catalyst powder through outlet ofS1 to plenum chamber is 17.5%.

• It appears that S1 also contributes slightly highercatalyst flow towards fractionator.

• Secondary cyclone S3 receives maximum quantity ofcatalyst powder (52%).

• Vortex breaker of this cyclone releases 54% of catalystpowder, indicating good working of the cyclone.

• Outlet of S3 to plenum chamber releases the leastquantity of the powder (9.5%).

• Mathematical modelling of the radiotracer data obtainedat various locations corroborated the scanning results