Raw Material Usage Out of Tank that is filled by 55 gal drums

[Brandon Vincent]

All,

I'm quite new to SEEQ, so bear with me. I'm trying to build out a workbench to reflect daily raw material usage out of a small tank. I would like to calculate the daily usage amount by taking the ending - starting tank levels. I have a formula to convert our storage tank level % into total mass (kgs). As you imagine, the calculation is quite easy whenever no new drums are added to the tank.

The problem arises when I have days they add new material to the tank (typically every 3-4 days). Since the new raw material is added via full 55 gal drums, I would rather calculate this additional volume at # of drums x "standard wt./drum" (versus direct tank level increase). I want to be able to capture any heels left in the 55 gal drums as "usage" for that day. Each drum increases the tank level by ~21%, so it should be pretty easily to identify and calculate # of drums and the corresponding total wt. Nearly every time the tank is filled, x2 drums are pumped into storage tank back-to-back, but there can be time either only 1 or as many as 3 drums are pumped in. 

Once I can identify these x2 conditions, the daily usage should be "EndTankVolume" - "StartTankVolume" - "#DrumsOffloaded"x"321kg/drum".

Any help would be much appreciated. 

 

 

[Siti Tay]

Hi Brandon Vincent, 

May I clarify the question? the issue arises when the drums loading occur in the middle of the day which causes your daily condition to split? If this is the case, one way to calculate the total material flow out of the tank daily could be as follows:

Step 1.  Use Composite Condition with intersection logic between "not loading condition" and "daily condition". 

This will result in splitting the daily condition based on the not loading condition

Step 2. Use Signal from Condition to calculate the tank level delta (End value - Start value) bounded to the condition (1) and place the statistic at the start of the capsule. The result below shows 2 value for Sep 2023 capsules, one at 00:00 and another one at 13:32 timestamp. 

Step 3. The delta value will be negative as the End value is smaller than Start value. Use Formula, abs() function to take the absolute value (positive value) 

$end_start.abs()

Step 4. Find the Sum of delta (End value - Start value) using Signal from Condition and bound the calculation to the "daily condition". This should be the total amount of material flow out from the tank daily despite having drum loading in the middle of the day.

 

If the steps mentioned earlier don't apply to the problem you're facing, here's how you can calculate how many drums have been loaded.

Step 1. Use Signal from Condition to calculate the tank level delta (End value - Start value) during "drum loading" condition. 

Step 2. Use formula to calculate the number of drums loaded by dividing it with 21% (as mentioned in the question, 21% level increased per drum loaded). The floor() function is used to round a numeric value down to the next smallest integer.

For example if the tank level during drum loading is 68.69%, 68.69%/21% = 3.27. The floor function round the value down to 3 drum. 

($level/21).floor().setunits('')

 

Let me know if this helps.

Edited October 9, 2023 by Siti Tay