Regarding whether feeding and discharging of the spherical tank can be carried out simultaneously?
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My facility is equipped with 6 ethylene spheres, each with a capacity of 2000 m3. Some supervisors have said that it’s not possible to discharge material from the spheres while simultaneously feeding them. I checked various manuals related to such spheres but couldn’t find any clear regulations on this matter. I was wondering if there are any such rules among fellow sailors; what do everyone do in this regard? Is it possible to enter and exit simultaneously, thereby reducing the frequency of container switching and preventing mistakes?
This post was last edited by ylb913 on 2018-7-10 21:04. Theoretically, it shouldn’t be prohibited, but in practice, it becomes a bit more difficult to monitor the liquid level in one or two tanks. Especially when there are multiple tanks involved for receiving or dispensing liquid, the changes in the liquid level occur more slowly, making it harder to detect any abnormalities. When multiple tanks are involved in simultaneous transactions, it is generally not possible to see the amount of fluid transferred in each individual tank; instead, calculations are made based on changes in the liquid level.
Is the discharge from your ethylene sphere tanks done using pumps?
Yes, the quantity has to be calculated based on the liquid level. If material is not added and removed at the same time, the tank will fill up and become empty in just a few hours; it’s also necessary to switch tanks frequently at night, which makes problems likely to occur
Yes, the pressure required by the user is high; liquid ethylene is pressurized using a layer, vaporized, and then sent out
Under normal circumstances, it is best not to use this method; the disadvantages are: 1. It is difficult to measure the quantities of items entering and leaving the inventory； 2. The pump struggles to achieve the required flow rate, resulting in abnormal delivery ； 3. It is impossible to prove the compliance of the products delivered. 4. If there is a failure in the distillation tower system, it has a significant impact on the pumps and the quality of the product.
They are usually not done together, let alone in your case where there are 6 of them – there’s absolutely no need for that
There should be no problem ensuring the quality of the product, as issues with ethylene quality are mainly caused by problems in the deacetyleneation process in the upstream system; it takes some time for these issues to affect the product, so it’s possible to switch to the tank designated for defective products in advance； I also considered the possibility that the pump couldn’t deliver fluid, as I had never encountered this situation before. However, in the past there was a case where an ethylene tank wasn’t emptied for an extended period of time, and gas would accumulate at the liquid level at the bottom of the tank; this would in turn cause air to enter the pump, resulting in its inability to deliver fluid
None of the 6 tanks are large; they have a high production rate, so the tanks need to be replaced every few hours. Over time, this can easily lead to problems
First of all, ensuring product compliance is not a matter of choice; rather, it is necessary to obtain a test report to prove the product’s compliance. The fact that a problem has not occurred does not mean it will definitely not occur; in any case, there are potential risks. You must be aware of these potential risks, as well as the level of loss you are willing to accept under such operating conditions.
Well, this issue will be carefully discussed, and a suitable solution will be chosen in the end. Because a mistake could cause the 5 downstream users to stop operating, various factors need to be taken into consideration. Thank you!