flow dynamics study of catalyst powder in ccu for ......2017/04/25 · s1 450 2 9 13 s2 1650 4 10...
TRANSCRIPT
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
2000
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4000
5000
6000
he
igh
t in
mm
count rate
CCU line1
0 50 100 150 200 250 300
0
1000
2000
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4000
5000
he
igh
t in
mm
count rate
CCU line2
0 50 100 150 200 250
0
1000
2000
3000
4000
5000
he
igh
t in
mm
count rate
CCU L3
S2 S3 S1
0 50 100 150 200 250
0
1000
2000
3000
4000
5000
he
igh
t in
mm
count rate
CCU L3
0 50 100 150 200 250
0
1000
2000
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4000
5000
he
igh
t in
mm
count rate
CCU line2h
eig
ht
in m
m
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