GIFSQ Tools · Module 17 — Food Processing, Thermal Engineering & Utilities · Tool 331 of 500
Work out the theoretical powder yield of a spray drying run from the feed solids and powder moisture, then the actual yield and the powder lost in the dryer.
Try sample values — fills the form with the worked example below.
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Theoretical powder (kg)
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Yield (%)
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Powder lost (kg)
Equation: Theoretical powder = feed × feed solids ÷ 100 ÷ (1 − powder moisture ÷ 100); yield (%) = powder collected ÷ theoretical × 100; loss = theoretical − collected.
Method: Solids mass balance for spray drying, standard food process engineering practice (Heldman and Singh); the theoretical powder carries all feed solids at the stated powder moisture.
Assumptions: all feed solids report to the powder; powder moisture is uniform; no solids leave with the exhaust air in the theoretical case.
Limitations: real losses include wall deposits, cyclone carry-over and fines; a yield above 100% means a weighing or moisture error.
Rounding: masses and yield to 2 decimal places; intermediates unrounded.
This is a calculation aid, not a laboratory report — confirm against your accredited method before citing a value.
Method: Solids mass balance for spray drying, standard food process engineering practice (Heldman and Singh); the theoretical powder carries all feed solids at the stated powder moisture.
Assumptions: all feed solids report to the powder; powder moisture is uniform; no solids leave with the exhaust air in the theoretical case.
Limitations: real losses include wall deposits, cyclone carry-over and fines; a yield above 100% means a weighing or moisture error.
Rounding: masses and yield to 2 decimal places; intermediates unrounded.
This is a calculation aid, not a laboratory report — confirm against your accredited method before citing a value.
Worked example: 1000 kg of feed at 30% solids, 290 kg collected at 4% moisture: theoretical powder = 312.50 kg, yield = 92.80%, loss = 22.50 kg.
Enter values above to see results.
Well-run milk powder dryers reach 90–95% yield; sticky products such as fruit juices run lower without a drying aid. Tool 331 of 500 — GIFSQ
