Urgent! Question: Drainage issues in the oil tank area!
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In the design of oil depots, we generally consider installing drains and funnels in the tank area; the drainage pipes in this area are buried underground, with inspection wells also set up within the tank area. But now some experts say that wells should not be installed inside the fire dike, and that the drainage pipes in the tank area should be raised above ground level?
Wells indeed should not be installed within the tank area, but it’s not clear exactly how the drainage pipes should be laid!
Drain ditches are arranged around the tank area, using the slope to guide rainwater to the external rainwater wells.
Here, steel pipes are used to connect the flow and direct it to a zero-level tank, where it is pumped away after simple oil removal.
This problem stems from the fact that the codes for cofferdams in oil tank accidents do not permit the design of funnels, but they do not stipulate that drainage systems cannot be included within the cofferdam. We have encountered this problem as well, and the solution is to add valves at the outlet of the drainage design. The safety assessment also makes sense. Of course, those who set the standards don’t know whether they are copying others or have never been at the production site. In short, there are indeed unreasonable aspects in the relevant specifications for accident cofferdams.
Experts suggest that during heavy rainfall, water may enter the oily wastewater system through observation wells, resulting in a mixing of rainwater and wastewater; if this is the case, the upper part of the observation wells can be raised appropriately.
Here, we usually set up sump pits, and then create valve switching wells on the outside of the cofferdam; this is what’s known as three-level prevention and control. Since the pipeline is laid on the ground, is a pump used to move the fluid away?
We designed a bypass in the oil discharge pipeline of each tank inside the fire dike; each bypass is connected to a funnel for discharging the oily wastewater at the bottom of the tank. Valve chambers and water seal chambers for diverting rainwater and oily wastewater have been installed along the fire dike, but experts say funnels still cannot be set up in the tank area……
There is no need to set up wells within the cofferdam area anymore. Drain ditches can be installed around the cofferdam to drain the water from outside the cofferdam into the water seal well. Behind the water seal well, a pool for collecting initial rainwater or wastewater from accidents can be installed, as well as a valve well for diverting the flow – one route leading to the rainwater treatment system and the other to the wastewater treatment system. Enter the wastewater treatment system 15 minutes before it starts to rain, and enter later.