Storage issues of mixed aromatics
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I have a question for experts: recently, our company has been using internal floating roof tanks to store mixed aromatics, but the quantities recorded are always inconsistent. There is significant loss. I searched for many reasons, but no issues were found. Personally, I think it might be a problem with the valve that is causing the internal leakage. Because these internal floating roof tanks were originally intended for storing aviation fuel. The business now needs to install mixed aromatics. What kind of valves do people think are suitable for mixed aromatics? Or could it be some other problem? Appendix: Mixed aromatics, properties: colorless and transparent liquid; odor: has a distinctive smell; an aromatic mixture obtained through the extraction of narrow-distillation-range reformed aromatics. It contains benzene, toluene, and xylene. It can be used as a raw material for petroleum resins, gasoline, and solvents. Specifications: Specific gravity (at 20°C): 0.845–0.855; Initial boiling point: not less than 87°C; Final boiling point: not more than 115°C; Acid wash colorimetry (using standard color solutions): not more than grade 4, ≤20; Evaporation residue: 0.0012
Ball valves are not suitable for chemical products; gate valves should be used instead! Moreover, mixed aromatics are relatively easy to volatilize
It doesn’t seem to be due to internal leakage in the valve; if there were internal leakage, there would have to be some place for the fluid to go, right? After all, there’s only one feed line and one loading line. Is it because the floating disc isn’t sealed properly, or the oil measurement hole and the level gauge port aren’t tightly sealed leading to severe evaporation, or are the ventilation holes in the pipe wall too large? . For valves, choose a globe valve
There shouldn’t be any problem with choosing the tank type. I’m not sure what the poster means by saying the quantities don’t match
It’s that after sending out the goods in one container, the loss is too high. It far exceeds the specified loss!
Is it a measurement issue? With the density of the mixed aromatics at 0.85 as you mentioned, volatilization should not be too severe. It’s possible that there were inaccuracies in the measurements at various stages during shipment. I’m not sure whether you load the goods onto trucks or ships; is tank measurement used for shipping by sea? Is it still a flow meter? Still a ship? Still the scale? Is it dedicated for specific use? Is the pipeline properly handled after installation? Deviations are related to many factors, and a systematic analysis is required to identify them.
As the original poster said! It’s the excessive loss of oil during storage in the tank! The quantities don’t match! I wonder if your storage tanks are equipped with nitrogen sealing! If not, it could be this reason that causes the excessive volatilization of mixed benzene. Also, our company uses internal floating roof tanks to store mixed benzene! Such a thing has never happened before.
Oh, that’s the vehicle used for building houses in our city. It really has powerful functions. :(
Do internal floating roof tanks also require a nitrogen seal? It shouldn’t be necessary to do that!
Hehe, it’s necessary! The function of a nitrogen seal is as follows: it can reduce the evaporation of oil, thereby minimizing environmental pollution and the risk of fires caused by oil vapor evaporation. Supplying gas to oil tanks also helps to reduce the likelihood of those tanks collapsing. All the floating-roof tanks in our facility are equipped with nitrogen seals!
Reason 1: The mixed aromatics coming from the production units contain a high proportion of light components, which volatilize significantly during storage and loading (due to the absence of sealed, quantified loading systems and vapor recovery systems). 2. Inaccurate production equipment or storage and transportation measurement systems lead to errors. 3. Equipment or human factors (analyze more carefully).