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Why is there a discrepancy of solids at sampling points?

Q: Ours is a fertilizer industry and within the premises we transfer phosphoric acid from the phosphoric acid production facility to the fertilizer production facility. The distance of the pipeline might be around 400m but the difference in issue and receipts generally comes out to be 100s of tons per day. Can you tell me what could be the possible problem? Other info required:

1. Phosphoric acid has around 5% solids
2. Sampling point in phosphoric acid tank is at the bottom
3. Sampling point in the fertilizer plant is at a higher level(25 ft) and is preceded by a lot of bends.

A: There could be a difference in solids at the two sampling points. Solids tend to accumulate in the bottom unless the tank is agitated. Solids may also accumulate in bends.

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Why is there a discrepancy of solids at sampling points?
Ours is a fertilizer industry and within the premises we transfer phosphoric acid from the phosphoric acid production facility to the fertilizer production facility. The distance of the pipeline might be around 400m but the difference in issue and receipts generally comes out to be 100s of tons per day. Can you tell me what could be the possible problem? Other info required:

1. Phosphoric acid has around 5% solids
2. Sampling point in phosphoric acid tank is at the bottom
3. Sampling point in the fertilizer plant is at a higher level(25 ft) and is preceded by a lot of bends.

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