Application of Decanter Centrifuge in Wheat Starch Production

1. Application Scenarios and Process Flow

1. Slurry Preparation: Mix flour and water at a ratio of approximately 1:0.85–0.95 to form homogeneous hydrated slurry.
2. Homogenization and Maturation: Conduct high-pressure homogenization (about 100 bar) to promote protein coagulation and particle dissociation, improving subsequent separation efficiency.
3. Core Three-phase Decanter Separation:
   • Heavy Phase (A-starch): With a density of about 1.5 g/cm³, large particle size (20–40 μm) and high purity, it is further refined into finished starch.
   • Intermediate Phase (B-starch + Gluten): B-starch has fine particles (less than 10 μm) and mixes with gluten protein; wet gluten and B-starch can be recovered through washing.
   • Light Phase (Pentosan / Yellow Water): Contains soluble sugar, residual protein and pentosan, available for by-product recovery or wastewater treatment.
4. Post-treatment: A-starch and B-starch undergo screening, multi-stage washing and dewatering (moisture content ≤ 40%), followed by flash drying; wet gluten is washed, squeezed and dried to produce vital wheat gluten.

2. Separation Principle (Density Difference & Centrifugal Sedimentation)

• Separation relies on density discrepancy: A-starch (1.5) ＞ B-starch/Gluten (1.3–1.4) ＞ Pentosan solution (≈1.0).
• The bowl runs at high speed (1500–4000 rpm, separation factor 3000–8000 g). A slight speed difference (2–5 rpm) between the bowl and conveyor pushes solid materials for continuous solid-solid-liquid three-phase separation.

3. Core Advantages (vs Traditional Water Washing & Disc Centrifuge)

• Fully Continuous High Efficiency: 24-hour stable operation, single unit capacity: 20–50 m³/h; traditional batch washing takes 8–12 hours per batch.
• High Yield and Purity: Total starch recovery ≥ 98%, A-starch purity ≥ 99%, gluten recovery rate ≥ 90%.
• Water & Energy Saving: Water consumption reduced by 30%–50% compared with the traditional washing process with closed water circulation, lowering environmental treatment costs.
• Strong Adaptability: Handles slurry with solid content of 15%–40%, tolerant to fine impurities without easy blockage; disc separators are prone to clogging and frequent cleaning.
• Stable Product Quality: Automatic control minimizes manual intervention and ensures consistent batch quality.

4. Main Models & Key Technical Parameters

• Mainstream Model: Three-phase Tricanter Decanter; double-cone decanter for fine starch recovery in partial working conditions.
• Typical Parameters:
  • Bowl diameter: 300–600 mm
  • Rotation speed: 2500–3500 rpm
  • Differential speed: 2–5 rpm
  • Separation factor: 5000–7000 g
  • Processing capacity: 30–40 m³/h (calculated by slurry)
  • Solid moisture content: A-starch ≤ 38%, B-starch ≤ 45%

5. Industrial Application Value

• High Comprehensive Economic Benefit: Co-production of food-grade high-purity A-starch, industrial/feed-grade B-starch and high-value vital wheat gluten to maximize profit.
• Production Cost Optimization: Continuous operation reduces labor cost, saves water and power consumption, and cuts raw material loss via high recovery rate.
• Environmental Compliance: Low water consumption and sewage discharge, easy to match with wastewater treatment systems to meet green production standards.

6. Common Operational Problems & Solutions

• Poor separation effect (low starch purity / gluten loss): Adjust rotation speed, differential speed, feed rate and slurry concentration & temperature; optimize homogenization performance.
• Excessive vibration and abrasion: Ensure dynamic balance of rotating parts, stable differential gear operation and intact wear-resistant lining on the conveyor; regularly maintain bearings and mechanical seals.
• Material blockage: Control slurry solid content within 40%, remove large particle impurities, and optimize conveyor lead and cone angle design.

7. Summary