Starch Dewatering by Hi-Bar Filtration

Transcription

1 Starch Dewatering by Hi-Bar Dewatering of Starch Suspensions by Continuous Pressure 3 t2 = OO t2 = 6 s t2 = 3 s t2 = s Pressure difference p 2 1 p ce,5 1 2 / 211 e S r Saturation S

2 BOKELA Hi-Bar Oyster Filter Continuous Pressure The Oyster Filter a continuous pressure filter especially designed for the chemical, pharmaceutical, food and life science industry. The Oyster Filter is made for applications with: valuable products fine and difficult to filter particles toxic products low-boiling suspensions frequent product changing high quality standards extreme process conditions Basics The Product A-Starch Globules The smaller the particles, the more difficult the solid liquid separation Particle Size Distribution of Wheat Starch (schematic) 35 B-Starch A-Starch 3 B-Starch Globules Volume% Wheat Starch 1 5 x 5 (B-Starch) x 5 (A-Starch) Particle Diameter (µm)

3 Basics The Process A-Starch Suspension Horizontal Peeler Centrifuges Mechanical Dewatering Vacuum Filters Vertical Belt Presses (Automatic Pressure Filters) Hi-Bar-Filters (hyperbaric Filters) Thermal Dryer Native A-Starch Basics The Objectives Good Dewatering (low residual moisture content) Energy saving in the succeeding dryer Investment saving for new plants (smaller thermal dryer Capacity improvement for existing plants High Starch Throughput Small apparatus sizes Continuous Operation Investment saving for peripheral equipment (smaller storage tanks etc.) Mechanical Dewatering

4 Basics The Equipment Equipment Driving force Dewatering Throughput Size Operation Horizontal Peeler Centrifuge 8 x g-force (& p up to.9 bar) 38-4% (37-38%) 4-5 kg/m²/h up to 18 mm diameter discontinuous Vacuum Filter p up to.7 bar 4-42% 1-2 kg/m²/h up to 1 m² continuous Vertical Belt Press p up to 6 bar 34-36% 5-15 kg/m²/h up to 144 m² discontinuous Hi-Bar Filter p up to 6 bar 34-36% 6 8 kg/m²/h up to 24 m² continuous -5- Basics The Equipment Equipment Invest cost for Equipment Invest cost for periphery Energy cost / Invest cost for thermal dryer Horizontal Peeler Centrifuge Vacuum Filter Vertical Belt Press Hi-Bar Filter

5 Basics The Equipment Equipment Horizontal Peeler Centrifuge Vacuum Filter Vertical Belt Press Hi-Bar Filter Advantages Good flexibility to changing products Good accessibility Continuous operation Residual moisture low High throughput of modified starches possible Residual moisture low High throughput Continuous operation Good accessibility CIP of modified starches possible Disadvantages Residual moisture high Discontinuous operation CIP only limited Throughput limited Residual moisture high Large units required Discontinuous operation Difficult belt alignment CIP only limited Accessibility limited Only two operational units installed (but working successfully) Why Pressure : Low Residual Moisture Content capillary entry pressure p ce pressure difference p t 2 = OO mechanical demoisturing limit (S R = remaining Saturation) t 2 = 6 s t 2 = 3 s t 2 = s S r,5 1 Saturation S reduced moisture contents (overcoming of capillary forces) p = 2 bar p <,8 bar p < P ce S = f [ ( p p ce ), t 2,...] p 1 p 1 p 1 filter cloth p 2 p 2 p 2 p = p 1 p

6 Why Pressure : Low Residual Moisture Content Vacuum filter cake: wet and sticky mc = 41 % Hi-Bar filter cake: dry (powder like) mc = 35 % Why Pressure : High Solids Throughput. M s = m& s A F = ρ s 2 η r n 6 1 ( 1 ε) κ p A 3, 6 L c α 36 F product parameters process parameters machine parameters product parameters process parameters machine parameters m s [kg/m²s] specific solids throughput η L [kg/ms] filtrate viscosity κ [-] solids concentration coefficient r C [1/m] cake resistance ε [-] porositiy n [1/min] filter speed p [N/m²] pressure difference in form zone α 1 [ ] cake forming angle Α [m²] filter area

7 BOKELA Hi-Bar Process and Plant Design Compressed air steam (p Dampf ) Wash water Standard design (large units) with horizontal pressure vessel for bulk materials P Dampf = P 1 P 1 : vessel pressure P 2 : at cake discharge P 2 > P 1 Filter cake Feed Filtrate, condensate and air p = P 1 -P ATM 6 bar OYSTER-Design (smaller units) with vertical pressure vessel for sophisticated applications (chemical, pharmaceutical and food industry) BOKELA Hi-Bar Oyster Filter Disc and Drum Filter Oyster Disc Filter Oyster Drum Filter Main Parts steam cabin Filter Pressure Vessel Sluice

8 BOKELA Hi-Bar Oyster Filter Exchangeable Filter Cells / Segments Disc filter segments prepared for fitting Drum filter cells Simple and quick cloth change due to exchangeable filter segments BOKELA Hi-Bar Oyster Filter Cleaning in Place Enclosed system: No emissions to atmosphere or surrounding No pollution of product Cleaning in Place of complete system possible Filter cloth cleaning deflector plates Cloth wash bar with nozzle Several Rotating CIP-Nozzles installed inside the vessel

9 BOKELA Hi-Bar Oyster Filter Excellent Accessibility - Easy Maintenance excellent accessibility for maintenance work by completely hinged pressure vessel no "release of vessel" inspection required Pressure Vessel Vertical pressure vessel for optimum accessibility Opens and closes automatically MOC: stainless steel possible Hydraulical locking device (Scholz) BOKELA Hi-Bar Oyster Filter Discharge Sluice Sluice with proven and well established valves Conical intermediate chamber to avoid bulk bridging MOC: Stainless steel Heating of intermediate chamber possible CIP

10 BOKELA Hi-Bar Oyster Filter Sizing Type Diameter Filter Area Floor Space XS1.9 m 1. m² 2.,2 x 2.4 m XS2.9 m 2. m² 2.2 x 2.4 m S4 1.4 m 3.6 m² 2,8 x 2,8 m Drum Filter S5 M7 1.4 m 1.9 m 5. m² 6.8 m² 2.8 x 2.8 m 3.5 x 3.5 m M9* 1.9 m 8.8 m² 3.5 x 3.5 m M11* 1.9 m 1.8 m² 4,5 x 4.5 m M12* 1.9 m 12.8 m² 4.5 x 4,.5 m * no single cell design Type Diameter Discs Filter Area Floor Space XS1 2.2 m 1 6. m² 3.5 x 3.5 m Disc Filter XS2 XS3 2.2 m 2.2 m m² 18. m² 3.5 x 3.5 m 3.5 x 3.5 m XS4 2.2 m m² 3.5 x 3.5 m BOKELA Hi-Bar Performance Data Duty p Specific troughput Cake moisture Filter speed Filter area for 2 to/d Filter type [bar] [kg/m²/h] min [kg/m²/h] max [Weight %] [rpm] [m²] [-] Native A- Starch Oyster disc XS2 Native A- Starch Oyster disc XS1 or Oyster drum M7 modified A- Starch Oyster disc XS

11 BOKELA Hi-Bar Performance Diagram Product: native A-Starch Range of Operation 6. bar 2 Dry Solids Throughput [kg/m²/h] bar 4 2 min..5 rpm standard 1.5 rpm max. 3. rpm,,2,4,6,8 1, 1,2 1,4 1,6 1,8 2, Square Root of Filter Speed [rpm.5 ] BOKELA Hi-Bar Oyster Filter In Brief Low residual moisture High specific throughput Continuous filtration process with disc- or drum filters, installed inside a pressure vessel High filtration pressure difference of up to p = 6 bar Complete cake discharge by air-blow-back with snap-blow valve (blow-off air serves for the filtration process) Enclosed system Good accessibility Simple maintenance Simple and quick filter cloth change due to filter segments / cells High flexibility at fluctuating product properties by - Variable cake formation angle (adaptation during operation) - Variable cake thickness from 5 to 5 mm - different pressures in single process zones possible Available in a wide range of filtration area and throughput

12 Vacuum Dynamic Crossflow Membrane Sieve DYNO Filter (MF) Filter Revamping Services Disc Filter Hi-Bar Filter DYNO Filter (sieve) Filter Revamping Trouble Shooting Consulting Development Backflush Drum Filter Hi-Bar Oyster Filter FILTRATEST Pan Filter Pressure Hi-Bar Pressure & Steam Pressure Backflush Filter Laboratory Equipment FILTRATEST DYNOTEST BOKELA GmbH Tullastr Karlsruhe Deutschland Tel.: Fax: BOKELA Australia Pty Building 5 Spring Lake Commercial 1 Springfield Lakes Blvd Springfield Lakes, QLD 43 Australia phone : fax: bokelaofaustralia@bokela.com BOKELA do Brasil Ltda R. Santiago Ballesteros 61 Sala 6, Cinco Contagem MG Brazil phone: fax: bokeladobrasil@bokela.com