docOlivier Rousseaux - Australian Oilseeds Federation
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Olivier Rousseaux - Australian Oilseeds Federation
GRINDING EFFICIENCY IN THE AQUAFEED INDUSTRY Olivier Rousseaux orousseaux@stolz.fr ASIA SALES DIRECTOR ISF – Sydney - 2009 GRINDING EFFICIENCY IN THE AQUAFEED INDUSTRY CONTENT INTRODUCTION A] Parameters affecting grinding in the aquafeed industry Raw Materials / Grinding design B] Main Mechanical parameters we can change for better result C] Global solution CONCLUSION ISF – Sydney - 2009 INTRODUCTION IMPORTANCE OF THE GRINDING GRINDING SIZE REDUCTION GRINDING SIZE REDUCTION GRINDING SIZE REDUCTION GRINDING SIZE REDUCTION • Surface area • Smoothen the process – Dies blockage – Uniformity of the powder • Quality of finished product – Gelatinization – Digestibility – Palatability ISF – Sydney - 2009 A] PARAMETERS AFFECTING FINE GRINDING A1] RAW MATERIALS Which raw materials: Corn, Soya, cassava… Wheat bran, rice bran… Fish meal, feather meal… Grinding design Either pre-grinding or post grinding system Either 1 or 2 step(s) grinding Using pulverizer or hammermill ISF – Sydney - 2009 A] PARAMETERS AFFECTING FINE GRINDING A2] RAW MATERIALS a) Physical aspects Initial size of the particles initial size, capacity b) Biological aspects a) Moisture content Moisture content, b) Fat content fat content, c) Hardness hardness, capacity capacity capacity BASICALLY , RAW MATERIALS have to be used as what they are ISF – Sydney - 2009 A] PARAMETERS AFFECTING FINE GRINDING A3] GRINDING SOLUTION / DESIGN • 2 Steps grinding – Coarse grinding using hammermill (screen 3mm) – Fine grinding using pulverizer • 1 Step grinding – Using hammermill (screen 0,7mm) – and special sifter (sieves 300µm to 600µm) • In both cases, the particles size of the ground product matches the requirement… but at which cost ISF – Sydney - 2009 A] PARAMETERS AFFECTING FINE GRINDING A4] FACTS : HAMMERMIL vs. PULVERIZER Pulverizer : Needs a lot of aspiration High aspiration means high moisture losses High power consumption Hammermill : Need aspiration Reasonable power consumption Reasonable Moisture losses Cost : Electrical cost: easy to evaluate Wearing parts cost: easy to evaluate Moisture losses: difficult to evaluate ISF – Sydney - 2009 A] PARAMETERS AFFECTING FINE GRINDING A5] GRINDING COST : HAMMERMIL vs. PULVERIZER No. 1 2 3 Parameter HM Stolz Pulverizer 10 Actual Cap (T/H) 4 Electric Consumption - in kWH/Ton 24 28 - Electric Cost (US$/Ton) 1,4 1,7 Spare Parts - Hammer / Beater (US$/Pcs) 2,6 50 Number of Hammers 152 72 Total Hammer Cost/mch 401 3 564 Hammer Lifetime (Tons) 5 000 3 600 Hammer Cost (US$/Tons) (assump. 5000 T/month) 0,1 1,0 - Screener / Liner (US$/Pcs) 133 285 2 2 Number of Screen/liners Total Screener / Liner Cost / mch Screener/Liner Lifetime (Tons) 266 570 2 500 3 600 HUGE SAVING Screener Cost (US$/Tons) (assump. 5000 T/month) 4 0,1 - - Counterbeater & Liner: in H26/Tons 0,06 - - Turbo sifter Screener: in US$/Tons 0,09 - TOTAL COST (IN US$/TON) 1.75 2.70 DIFFERENCE US$ 0.95 SAVING / MONTH (IN US$/MONTH) US$ 4 750 ISF – Sydney - 2009 A] PARAMETERS AFFECTING FINE GRINDING A6] COMPROMISE In terms of fineness Still with pulverizer we could get very fine particle … something which is not required Finer are the particles, higher is cost Compromise: Hammermill + Pneumatic System + TurboSifter ISF – Sydney - 2009 B] EQUIPMENT DESIGN AFFECTING EFFICIENCY B1] HAMMERMILL : ROTOR SPEED Generally : 1500 rpm hammermills rotors are of about 1 400 mm diameter 3000 rpm hammermills rotors are of 650 to 700 mm diameter Disadvantages of a 1500 rpm hammer mill vs. a 3000 rpm : The size Screen changing more difficult Needs more important screen surface Disadvantages of a 3000 rpm hammer mill vs. a 1500 rpm : Noise Fan makes more noise than hammermills, what ever its size Speed 3000 2900 2800 2700 2600 2500 2400 2300 2200 2100 2000 1900 1800 1700 1600 1500 1400 1300 1200 1100 1000 Screen 2,0 mm 2,5 mm 3,0 mm 3,5 mm 4,0 mm 5,0 mm 6,0 mm 570 593 612 626 637 647 641 559 591 620 645 665 695 709 549 592 630 665 696 745 779 542 594 643 688 728 798 851 537 599 658 712 763 852 926 534 607 675 740 800 909 1003 534 616 694 769 839 968 1082 535 628 716 800 881 1030 1163 539 642 740 834 925 1094 1247 546 658 766 870 971 1159 1332 554 676 794 909 1019 1228 1420 565 697 825 949 1069 1298 1511 578 720 858 992 1122 1371 1603 593 745 893 1037 1177 1445 1698 610 772 930 1084 1234 1522 1795 630 802 970 1134 1294 1602 1894 652 833 1011 1185 1355 1683 1995 676 867 1055 1239 1419 1767 2099 702 904 1102 1295 1485 1853 2205 730 942 1150 1354 1554 1941 2313 761 983 1201 1414 1624 2032 2424 Table giving medium size of particles in function of Screen size and rotor speed. ROTOR SPEED, PARTICLES SIZE ISF – Sydney - 2009 B] EQUIPMENT DESIGN AFFECTING EFFICIENCY B2] HAMMERMILL : SCREEN – DIMENSION AND SPECIFICATION Useful Screen Size , capacity Screen perforation, Particles size Screen Opening (%) , capacity Screen Thickness , Particles size Screen worn-out, capacity New screen t uc od Pr D o reb un WORN: while rebounding, the grain is taken again by the hammers Worn screen g din od Pr Opening% = D² * 0.907 / EA² NEW: while rebounding, the grain is returned outside Screen wearing effect t uc EA re u bo in g nd ISF – Sydney - 2009 B] EQUIPMENT DESIGN AFFECTING EFFICIENCY B3] HAMMERMILL : BEATER Beaters : Steel treatment and Wearing How can you control the best quality? A: no steel heat treatment or bad treatment B: correct steel heat treatment + C Addition 1: new beater 2: one side worn 3: both sides worn A: no steel heat treatment or bad treatment •concave wearing B: correct steel heat treatment : •convex wearing A: no steel heat treatment or bad treatment •Round shape wear B: correct steel heat treatment : •Spoon shape wear ISF – Sydney - 2009 B] EQUIPMENT DESIGN AFFECTING EFFICIENCY B4] AIR FLOW Air flow is made 2 main parameters: • Air flow : m3/h, … • Pressure: WC, bar For Coarse Grinding (Screens 2 mm and more): • Air Flow of about 8500 m3/h for 1 m² • Air Pressure is of about 300 to 500 mm water column on the screen For Fine Grinding (screen 1.5 mm and less): • Air Flow of about 5500 m3/h for 1 m² • Air Pressure of about 700 to 1000 mm water column on the screen ISF – Sydney - 2009 B] EQUIPMENT DESIGN AFFECTING EFFICIENCY B5] AIR FLOW THROUGH HAMMERMILL & AIR JET FILTER AIR SPEED : Air speeds: 22-23 m/s through the destoner 4-6 m/s through the grid 2.5 to 3 m/s through the filtering media AIR FLOW ACTIONS: Generally little effect on the particle size Enables product passing through the screen Depending of the hammermill feeder design: Better heavy materials removal. Will help reducing the T°increase of the ground product, avoiding down stream condensation AIR FLOW REGULATION : Allows a constant flow rate, whatever may be the pressure loss From where, a better de stoning Avoids any overload of the filtering media Allows a progressive air flow increase, avoiding inopportunely emptying of the stone box ISF – Sydney - 2009 B] EQUIPMENT DESIGN AFFECTING EFFICIENCY B6] GRINDING LINE DESIGN a) Mechanical handling b) Pneumatical handling ISF – Sydney - 2009 C] GRINDING EFFICIENCY IN THE AQUAFEED C1] HAMMERMILL : FEEDER + GRINDER The Feeder Dimension same as the grinding room Pneumatic Magnet Heavy particle remover Unique Very advanced System The Grinder Liner Screen Beaters Counters beaters But also for safety reasons Temperature control Auto greasing Screen sliding ISF – Sydney - 2009 C] GRINDING EFFICIENCY IN THE AQUAFEED C2] HAMMERMILL : FEEDER DESIGN Raw materials Air flap Layer thickness adjustable Feeder with variable speed Air inlet Magnet Air Heavy particles separator - Stainless steel Material to be ground –Stone –Sand –Any high density particle ISF – Sydney - 2009 C] GRINDING EFFICIENCY IN THE AQUAFEED C3] HAMMERMILL : BEATER & COUNTER BEATER Counters beaters Counters beaters increase Flow rate and fineness ISF – Sydney - 2009 C] GRINDING EFFICIENCY IN THE AQUAFEED C4] HAMMERMILL : SCREEN REPLACEMENT Step 1: Stop of feeder Step 2: Unlocking Step 3: Pushing out Step 4: Change of screen Step 5: Pulling in Step 6: Locking Step 7: Start of feeder Time = Maximum 3 MINUTES SAVE POWER AND TIME ISF – Sydney - 2009 C] GRINDING EFFICIENCY IN THE AQUAFEED C5] TURBOSIFTER Main features Rotor specially designed High speed Clock rotation Sieving drum rotates Low speed Clock rotation Sequenced rotation Compressed air @ 7bars When sieving drum could rotates Sequenced air pulsing Cross contamination less ISF – Sydney - 2009 C] GRINDING EFFICIENCY IN THE AQUAFEED C6] GLOBAL SOLUTION Grinding line for shrimps feeds or fish feeds ISF – Sydney - 2009 ISF – Sydney - 2009
