Coke Cutting Pump

[ShahabAPI]

What is the reliable mechanical seal plan for high pressure coke cutting pumps, BB5 Type? If we use plan 32, then approximately 10~20 lit/min is required for each mechanical seal cartridge. Any experience to use other plan such as 31?

Shahab Zardynezhad

 

[JJPellin]

Only one of our coke cutting water pumps uses mechanical seals. It uses utility water (basically, well water) for seal flush (API Plan 32) and has had excellent reliability. This pump was installed new to replace a much older pump about a year ago. It has never had any seal leakage. The previous pump and the pump in our other coker use packing with utility water flush.

Johnny Pellin

 

[ShahabAPI]

Thanks Johnny, considering discharge pressure about 300barg , using packing is interesting. Our pump is 12stages, BB5 with single mechanical seal each seal 20l/min seal flush of utility water. Do you use fixed speed motor in intermittent case?

Shahab Zardynezhad

 

[JJPellin]

The packing only sees suction pressure under any circumstances (about 1 bar), so discharge pressure really does not affect that part of the design. Both of our currently installed coker jet water pumps are 10 stages, BB5, close to 300 bar. Both of ours are driven by fixed speed induction motors larger than 3000 HP each. Our motors are only running when they are cutting coke.

Johnny Pellin

 

[SB1976]

Seal Plan 32 is absolutely fine for Coke Cutting pumps. Seal Plan 31 involves a cyclone separator which itself is prone to choking leading to damage of the mechanical seals due to starvation of seal fluid. In the case of Coke Cutting pumps, the pumping fluid is recycled water with coke fines. Hence, a much greater risk is involved.

Plan 32 may cause arrangement of good quality filtered water by end-user, but that's justified in view of the potential damage of the pump seal with plan 31 which is catastrophic.