Coke water tank

[Hedewandro Lucredi]

We increase the DCU feedrate but the coke water tank is the same. Our coke water tank is for drum decoking and drum quench. We are having a problem with coke fines in the decoking system and some dificulty to remove the coke fines by draining. Is there any criteria to design a new coke water tank ? Volum (diameter x height) ? Draining points ? Location of the suction pumps ? Hydrociclones ? We are analysing to replace this tank

[evan]

Hi. Conical bottom tanks are standard, inverted or normal depends. Taller is better with higher slopes to facilitate draining. Volume should be sufficient to quench and cut 1 drum with no additional water input. Jet pump suction is typically higher than quench pump. Cyclones can work if properly maintained but most sites do not have them. Automated draining valves with some DCS logic is a good approach to draining the system routinely because operators don’t do it……So yes, there are lots of design criteria and I think that’s the short list.

[Mike Kimbrell]

The key to managing fines in the decoking water tank is to keep the fines from getting into the tank. This means routine fines removal from the fines settling area in your pit. This is often called the maze as it is a tortuous path for the water to exit the coke pit and then get pumped into the decoking water tank. The design parameters are based on the size of the drum and the maze. If the maze gets full of fines, they were no longer settle and will end up in the decoking water tank. As long as you are draining only one coke drum at a time, the sizing of the maze and the decoking water tank should not need to change. The frequency of removing fines out of the maze will need to increase as the feed rate on the unit increases and the cycle time on the coke drums shortens.

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