Dipping Tape and Measuring Oil Tonnage
Friday, November 02, 2007
In oil industry or oil plant, there are a lot of oil storage tanks available. It is vital for the oil company to know their daily oil stock simply because they are in the oil business. Therefore, they need to measure the oil volume and further work out its tonnage. They need to know the exact volume of oil and to do that there are various methods. One of the traditional method is by using a dipping tape.
What is a dipping tape? Sorry, I could not find a suitable and proper definition for it. My own definition would be a tape made of from stainless steel (can be other material as well) and has some sort of calibration along it (up to 15m, or 20m, it depends on your tank height) and it's used to measure the ullage in a storage tank (filled with oil/liquid). Does anybody have a suitable definition of dipping tape?
I guess the next question from you will be: What is ullage?
The amount which a tank or vessel lacks of being full.
is the empty space present when a shipping container is not full.
The space in a tank not occupied by its contents. Used as a measure of storage space still available.
I hope the ullage definition would give you some idea on the concept.
For each storage tank, there'll be some sort of calibration table. From it, we can know what is the volume of oil at certain height. The tank height is also recorded in the calibration table. So, in order to know the volume of oil, we substract the tank height from the ullage (which we get from the dipping tape measurement), and we shall get the oil level height. From there, we can already get the volume of oil and work out the tonnage (with the temperature reading available).
posted by zaki yamani @ 12:00 AM,
- At Saturday, November 03, 2007, profmaster said...
Though it is the most used OLD method of tank level or tonnage measurement but is very confusing & erratic. The reson is that the tape slacks whenever you dip it into the tank due to viscosity & density of oils for which they are generally used. So one should be very careful rather I do not consider this method at all because most of the time readings are so erroneous that you land up with wrong estimates.
I prefer using a tube connected to the bottom drain or any other nozzle & straighten it up then measure the height from any known datum. This will give you 99-100% accuracy then any costly tape.
- At Saturday, November 03, 2007, zaki said...
Yeah, actually the dipping tape is a very classic technique to measure the levels. There are a lot more techniques which have better accuracy and reliability. Perhaps later I should make some more posts on that...Thanks...
- At Saturday, November 03, 2007, said...
There are other methods to measure which is call ATG (auto tank gauging) where we can monitor the level, tonnage and volume at one time for a number of tanks.
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I’m Zaki. I used to be a project, process and chemical engineer. Few years ago I successfully became a Chartered Engineer (IChemE) and Professional Engineer (BEM). I'm now employed as a chemical engineering educator/researcher/consultant. Hope you like reading my blog. I welcome any feedback from you. My email: zaki.yz[alias]gmail.com. TQ!