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T11 · Sustainability / LCARecycling Technology & ProcessingGATE 2027 Syllabus (XE5)Shop-Floor Standard
Mechanical Recycling Mass Balance & Washing Flake Yield
Calculates the net industrial yield percentage of clean, hot-washed flakes produced from raw baled post-consumer plastic waste after accounting for label, cap, dirt, and moisture losses.
Mathematical Canonical Relation
Plain Formula: Y_flake = (M_clean_flake / M_raw_bales) * 100
Live Engineering Parameter Solver
Input your production or test values below for instant, verified output.
Verified Engine
bale_input
Range: 10 – 5000 Tonnes
dirt_loss
Range: 2 – 25 %
label_loss
Range: 2 – 15 %
cap_fraction
Range: 2 – 10 %
Calculated Engineering Result:
72% Yield (720 Tonnes Flake)
Engineering Verification:Total reject loss is 28%. Also generates 60 Tonnes PO caps.
When & Where to Apply
Use when budgeting PET bottle washing plants, calculating recycling unit economics, and verifying mass-balance audits for CPCB EPR recycling credits.
Common Engineering Pitfalls
- Neglecting moisture in incoming wet bales during rainy season
- Failing to separate polyolefin cap yield (HDPE/PP) from clear PET flake yield
Physical Assumptions & Validity Limits
- Accurate weighbridge mass tracking for input bales and output gaylords/silos
- Moisture content of finished clean flakes is <1.0% after spin drying
- All reject streams (sludge, labels, PO caps, fines) are mass-accounted
Variable Symbols, SI Units & Dimensional Specifications
| Symbol | Variable Meaning | SI Unit | Typical Industrial Range |
|---|---|---|---|
| Y_{flake} | Net clean flake recovery yield | % | — |
| M_{clean\_flake} | Mass of clean hot-washed flakes produced | Tonnes | 720 |
| M_{raw\_bales} | Mass of raw incoming post-consumer bales | Tonnes | 1000 |
Worked Industrial Numerical Example: 1,000 Tonne PET Bottle Washing Plant Yield Audit
Problem Statement:
A recycling wash plant in Gujarat processes 1,000 Tonnes of post-consumer baled PET bottles. Process losses: 12% moisture & dirt, 6% PP/HDPE bottle caps, 8% PVC/OPP labels and fines, 2% color reject bottles. Determine clean rPET flake yield.
Step-by-Step Numerical Solution:
- Calculate total percentage loss: 28%
- Calculate clean flake mass: 1,000 Tonnes * (1 - 0.28) = 720 Tonnes
- Calculate yield: (720 / 1000) * 100 = 72.0%
Final Answer: Yield = 72.0% (720 Tonnes Clean rPET Flakes)
💡 Engineering Interpretation: A 72% net flake yield is benchmark performance for Indian municipal collection streams. The 60 Tonnes of separated HDPE/PP caps represent a secondary revenue stream at ₹45–55/kg.
Authoritative Technical Reference & Source Provenance
Recycling of Plastics by Francesco Paolo La Mantia (ChemTec Publishing, 2002), 1st Edition, Page 145-152.
Connected Curriculum Lesson
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