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.