Advantages and disadvantages of the oil unloading process and bin cleaning process for train tank cars

We use vacuum extraction here, followed by transfer to the tank area via a centrifugal pump; this method is effective for transferring ethylene glycol and acetic acid. During tank cleaning, a vacuum pump is used for suction, leaving about 40 to 50 kilograms of oil in the tank. We have not used any other processes. I think this method is relatively easy to maintain, with a low rate of equipment failures

In my opinion, the relatively good process at present is a combination of a submersible pump for oil transfer, a centrifugal pump for unloading, and a trough cleaning rotor pump. In the past, the process of \"vacuum oil extraction (tank cleaning) + truck-mounted centrifugal pump\" was used, which resulted in water waste and posed certain potential risks during oil extraction! ! I heard that abroad, first, the oil is unloaded there, and secondly, there are no pump rooms; instead, pipeline pumps are located outside the fire dike, which is very convenient. (In foreign oil tanks, the inlet and outlet for oil are separated, which is also something worth adopting by us!) ! :handshake :victory:

I strongly agree with the view of the gentleman above. 1. Vacuum evacuation leads to significant oil vaporization, which is harmful to the environment and safety ； The vacuum pump has low operating efficiency and high energy consumption ； The operation is complex; a vacuum pump requires a vacuum tank, and the vacuum tank constitutes a hazard, posing safety risks. It should be phased out! 2. Unloading oil using sliding vane pumps (rotor pumps); high-flow sliding vane pumps (rotor pumps) are expensive, have reduced efficiency, and their technology is not yet fully developed. 3. Oil is unloaded by combining a centrifugal pump with a vane pump (rotor pump). The vane pump is mainly used in conjunction with a centrifugal pump as an auxiliary unloading system; it is often employed for emptying the tank and transferring oil, thereby feeding the main pump. When only the residue at the bottom of the tank remains, the centrifugal pump is turned off and the vane pump is activated to empty the tank. It overcomes many of the disadvantages associated with pumping in vacuum systems, **eliminating safety hazards. 4. Unloading with an submersible pump: When using this method, neither the dip pipe nor the submersible pump experiences air blockage or cavitation, allowing the centrifugal pump to operate properly and efficiently and thus reducing the unloading time. 5. As for the three methods of removing residue from tanks, using a vacuum system is not favorable from an environmental and safety perspective. It is somewhat difficult to pump out the residual oil using submersible pumps. On the other hand, using positive-displacement pumps such as vane pumps (rotor pumps) to remove the residual oil offers advantages such as safer operation, lower levels of volatile gases produced, and the ability to send the oil directly to the storage area, with a simpler process. Therefore, using a submersible pump + unloading centrifugal pump + trough cleaning rotor pump for oil transfer is indeed the best process available at present. I wonder if anyone has any insights on equipment selection?

Currently, a combination of submersible pumps and centrifugal pumps is commonly used; swing pumps or paddle pumps are employed for bilge cleaning, while submersible pumps can be pneumatic, hydraulic, or electric. But there are also cases where submersible pumps are used directly for unloading, with slurry pumps used for cleaning the tank.

Is there a problem of hydraulic oil leakage and contamination when hydraulic submersible pumps are used in jet fuel tank cars?

Of course, there is pollution; generally, hydraulic submersible pumps are used only for transferring gasoline, not for transferring aviation kerosene. We have encountered accidents of hydraulic oil leakage in hydraulic submersible pumps. There must be no contamination in aviation fuel, especially Jet A-3 used in third-generation aircraft.

Which brother has the process diagrams for unloading methanol using train tank cars and for cleaning the silos? Please share them; I really need them. Thank you!

I work at a oil depot now, and centrifugal pumps are mainly used for cleaning the tanks; however, their efficiency isn’t very high. Recently, an experienced worker added a U-tube to the oil outlet, which significantly improved the efficiency. I’ve never understood why this works, and it’s really frustrating! ~

The gentleman on the 4th floor said that using a submersible pump + a centrifugal pump for unloading + a rotor pump for cleaning the tank is indeed the best process available at present; I’m not entirely in agreement with this. The new SP series of double-acting, contact-free vane pumps can eliminate one of these steps – specifically, the process becomes vane pump for transferring oil + centrifugal pump for unloading + vane pump for cleaning the tank. The residual oil can be completely removed, as the vacuum level can be maintained above 0.08. Moreover, the special internal structure ensures that there is no contact between the vanes and the stator, eliminating the need to replace the vanes. If the flow rate at the site is less than 250 cubic liters and the required head isn’t high, it’s even possible to use just one pump to carry out all three tasks: transferring oil, unloading, and cleaning the tank.

The vacuum method should not be recommended. There is a type of piston pump from Yueqing that is said to be good.