Improvement in First Carbonation Sludge Settling by Selection of a Better Flocculent Addition point and. Flocculent. Jeffrey L. Carlson, Ph.

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1 Improvement in First Carbonation Sludge Settling by Selection of a Better Flocculent Addition point and the Addition of Starch as a Second Flocculent. Jeffrey L. Carlson, Ph.D Upasiri i Samaraweera, Ph.D PhD

2 Modified BMA 65 Purification System at Minn Dak

3 Conditions that affect Settling of First Carbonation Condition of the beets Operation of the tower Operation of the washhouse Amount of lime used in Carbonation Operation of Preliming Operation of Main Liming Operation of First Carbonation Flocculent addition

4 Pre Carbonation at o and Intermediate Liming Pre Carb ph = 8.8 Temp = 80ºC Intermediate Liming ph = 11.0 Temp = 80ºC Coagulate Protein and Pectin Build Calcium Carbonate Crystals Calcium Insoluble Salts Precipitate CO2 Raw Juice Ca(OH)2

5 First Carbonation 11% CO 2 Juice from Main Liming Create Calcium Carbonate precipitate Reduce Hydroxyl y Alkalinity (0.100 g/100 ml as CaO) End point balance between settling and filtering or color and nonsugar removal Temp = 87ºC 32% CO 2

6 First Carbonation Thickeners Precipitated solids settle in thickeners and separate from the Juice Clear Juice Juice from First Carbonation CaCO 3 Sludge to Press

7 Flocculants Polymeric materials that help small particles clump together Charged (anionic or cationic) Charged particles adsorb onto parts of polymer chain Charge neutralization Neutral Sweep out particles

8 Anionic Polyacrylamide Anionic polyacrylamide Copolymerized acrylimide with acrylic acid FDA limits: No more than 5 parts per million on slice Environmental Concerns Degradation of polyacrylamide yields acrylimide a nerve toxin

9 Location of Original Addition Point Added to feed pipe pp to the thickener distributor Flocculation occurred in distributor Turbulence during flow to thickener broke floc Floc had to reform in thickener trays

10 Breaking and Rf Reforming Floc Each time the flocculent is less effective Slower settling Lower clarity Affect on Settling of Breaking the Floc and Letting it Reform Volume of Slude below the Break (ml L) Seconds First Second Third

11 Flocculent after the Distributer Avoids the breakup of the initial floc Better settling Better clarity

12 Added Flocculent to Each Tray Can control to the characteristics of the tray.

13 Starch as a Flocculent for 1 st Carbonation Sludge Components of Starch Polymeric glucose (C 6 H 10 O 5 ) n about 20% Amylose (linear) about 80% Amylopectin (branched) Typical Sources Wheat Corn Potato Rice Cassava Used in many industrial applications as a flocculent

14 Accidental Discovery at Minn Dak that Starch works as Flocculent Discovered when reprocessing powdered sugar Powdered sugar contains 3% cornstarch plugged the sugar end filters so started introducing it on the beet end

15 Accidental Discovery at Minn Dak that Starch works as Flocculent Carbonation station operators claimed the process went better 1 st Carbonation Sludge Settling after one minuet without and with starch

16 Caustic Improves Starch as Flocculent Adding caustic to the dissolved starch increases its flocculation ability Minn Dak currently adds enough caustic to make the starch solution 0.17% caustic Break Point for first Carb Settling Using Starch w/o and with Caustic

Heating Starch Solution Necessary ude k (ml)

solution upon 1000 heating 800 600 400 200 0 0

17 Heating Starch Solution Necessary ude k (ml) ume of Slu the Break Volu below Affect of 10 PPM Cold and Heated Starch Insoluble in Cold Water Dissolves to a thick, 1200 translucent solution upon 1000 heating Minutes No Starch Cold Starch Heated Starch

18 Settling of First Carbonation Sludge No Starch 10 PPM Starch in 0.167% Caustic Seconds 0 Volume of Sludge below the Brea ak (ml)

19 Advantages of Using Starch as a Flocculent Relatively Inexpensive No FDA Limit Synergistic affect with anionic polyacrylamide clearer solutions floc is better stabilized 1 st Carbonation Sludge Settling with polymer only and anionic polymer plus starch

20 Future Considerations Modified Starches Acid Modified Oxidized carboxyl groups Dextrin's cold water soluble Derivative Cross linked Stabilized Cationic Starch Acetates Use in Flume Water

21 Questions?

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