Tank car unloading typically involves the connection of a hose between the tankcar bottom valve and the suction line of a transfer pump. Depending on the viscosity of the material being handled, the diameter of the hose may be 2,3, or 4 inches in diameter. If the material being unloaded must be kept hot during transfer, then the hose may also be steam-jacketed and insulated (increasing its diameter even further). Low clearances under the tankcar and the physical weight of the hose can make connecting the hose difficult. Globetech Services, Inc. is sensitive to these issues and employs proven methods to maximize unloading efficiency while minimizing product losses. In certain circumstances a Portable Unloading Pig launcher/receiver (PUP) can be used as part of a system to pig the unloading hose and piping from the tankcar all the way to the destination tank.

After the product has been transferred from the tankcar, the hose must be disconnected to prepare for the next unloading operation. During this activity, the residual material in the hose is often drained to a slop system and some of it may be spilled to the environment. If the hose is not completely drained, any product remaining may create cross-contamination issues the next time it is used. The unloading rate is a function of piping system hydraulics and is effected by the capacity of the pump, the viscosity of the material being handled, the length & diameter of the suction hose, and the piping system through which it must be transferred.

If the viscosity of the material being unloaded is too high, then flow (and pressure) at the suction of the pump will fall below minimums and cause the pump to cavitate. Repeated and/or prolonged cavitation will reduce the useful life of the pump. Globetech can suggest approaches that will eliminate cavitation, while maximizing pumping rates.

Finally, there is always the concern for spills during the unloading process. While concern for the environment is paramount; spills can also be quite costly due to product loss, clean-up and disposal costs, and potential employee exposure. Globetech can suggest systems and devices to help prevent spills in the first place, and to help contain them should they occur.