Restriction in Coker unit thruput

[sinhackParticipant]

We are running 4 drum DCU with 24 hr cycle and we are making anode grade coke. The design capacity of the unit is 2000 MTPD. But we are not able to increase the thruput more than 1400 MTPD as increasing the thruput results in coke bed height going beyond safe filling height of coke drum in 24 hr. Our recycle ratio is 1.9 as we are constrained on furnace feed flow also. We are operating with minimum furnace feed flow. In current set up we are not able to decrease heading-unheading time. Coke bed cooling schedule is 2 hr steam cooling, 1.5 hr low range water cooling and 2 hr deluge water cooling. Can we decrease this time by giving more flow of cooling media and what should be the basis i.e how to go about this ? If any changes in process condition will help us ?

[Anonymous]

please give me suggestion in fractionator bottom circulation pump suction line chokin @ remove it problem more suggestion.
 
please send me ess_1980@yahoo.co.in
 
ok,
 Thanks

[Anonymous]

[quote]ORIGINAL: Guest

please g”e me suggest’on ‘n fract’onator bottom c’rculat’on pump suct’on l’ne chok’n @ remo’e ‘t problem more suggest’on.

please send me ess_1980@yahoo.co.’n

ok,
Thanks
[/quote]

[Anonymous]

[quote]ORIGINAL: Guest

[quote]ORIGINAL: Guest

please g”e me suggest’on ‘n fract’onator bottom c’rculat’on pump suct’on l’ne chok’n @ remo’e ‘t problem more suggest’on.

please send me ess_1980@yahoo.co.in

ok,
Thanks
[/quote]
[/quote]

[Anonymous]

There are a number of changes that could be made but I need to understand the economic drivers and the feed availability/constraints.  24-hour cycle is a long cycle time even for an anode coker.  This applies to the recycle ratio as well 1.9 is very high.  The most straightforward reply to your question is to reduce your recycle.  You should have plenty of time to cool and cut the offline drum.  Here is a typical cycle time you can review;

Total Fill Cycle, hrs

24

20

18

16

Time Requirements For The Offline Drum In Hours

Drum Switch

0.25

0.25

0.25

0.25

Steam to Fractionator

1.5

1.5

1.5

1

Steam to Blowdown

1.5

1.5

1

1

Water Quench

5

5

5

4.5

Drain

1

1

1

1

Unhead Drum

0.5

0.5

0.5

0.5

Cut Coke

4

4

4

4

Rehead Drum

0.5

0.5

0.5

0.5

Pressure Test

0.25

0.25

0.25

0.25

Backwarm Drum

9.5

5.5

4

3

 

24

20

18

16

Feed Rate,  MTPD

1400

1680

2240

3360

– sim
(sim.romero@gmail.com)

[Author]

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