Purity Drop

purity Drop

1. BALRAMPUR CHINI MILLS, UNIT- TULSIPUR PURITY DROP MOHD ANWAR SIDDIQUI DY.CHIEF CHEMIST

2. Purity The percentage ratio of sucrose (or Pol) to the total soluble solid (Brix) in the sugar product known as Purity Purity = Pol % x 100 Brix % Loss of sucrose purity in one stage to another stage is known as purity drop

3. Purity drop between juices at different stages During milling and clarification of juice the purity drop from one stage to other stage given as- 1-Primary juice to mixed juice- 1.30 to 1.60 unit 2-Primary juice to last mill juice 10.00 to 13.00 unit 3- Mixed juice to clear juice +0.45 to +0.60 unit 4-Clear juice to Filtrate juice 2.50 to 3.50 unit 5-Clear juice to U. Syrup 0.25 to 1.50 unit

4. Purity drop between massecuite to molasses 0.25 to 1.50 unit During sugar production process the purity drop between different type of massecuite to molasses given as- 1-R1 Mass.to R1 Hy . Molasses 1.00 to 1.50 unit 2-Raw Mass. to Raw Hy Molasses 10.00 to 12.00 unit 3-B Mass.to B Hy . Molasses 20 .00 to 24.00 unit 4-C mass. to Final molasses 20.00 to 22.00unit 5-R3 Mass.to R3 Molasses 10.00 to 12.00 unit 6-C1 Mass.to C1 Hy Molasses 15.00 to 17.00 unit 7-A1 Mass. to A1 Hy Molasses 18 .00 to 20.00 unit

5. Reason of purity drop The drop in purity of juices and massecuite to molasses is due to the fallowing factors L oss of sucrose molecule due bacterial growth L oss of sucrose molecule due decomposition of sucrose molecule by over heating L oss of sucrose molecule due inversion of sucrose molecule Deposition of sucrose molecule from mother liquor to the sugar crystal in case of massecuite to molasses Extraction of non sugars

6. Purity drop during cane Harvesting S ugar cane is raw material for sugar industry. It is perishable material for microbial deterioration hence the harvested material is available to the factory at minimum possible delay. The microbial deterioration of cane lead the reduction of recoverable sugar i.e . drop in purity. The purity drop depend on time lag between harvesting to crushing , atmospheric temperature and humidity . About 0.5-1% loss of sugar after one day at the temperature in range max. 31°C. and min. 5°C And it increases 4-5 % after one week

7. Purity drop during milling During extraction of juice the mixed juice purity is near about 1.30-1.60 unit less than primary juice purity and last mill juice purity is near about 10.00- 13.00 unit less than primary juice purity The drop in purity from primary juice to mixed juice or primary juice to last mill is due to more extraction of non sugars from mill. D ue to more extraction of non sugar result reduces the purity of mixed juice or last mill juice The range of purity drop from primary to mixed juice is limited if it increases more indicate loss of sucrose in mill due to bacterial growth indicate poor sanitation in other hand if it decreases inducate the mill extraction is poor

8. Purity drop during Clarification of juice During clarification of juice it is observed that the purity rise from mixed juice to clear juice 0.45 to 0.65 unit this is due to removal of non sugars during clarification of mixed juice to clear juice The purity drop between clear juice to filterate juice in range 3.0 to 5.0 unit this is due to dissolution of some non sugars during cake washing at vacuum filters The range of purity drop between clear to filterate juice if exceeded from 3.0 to 5.0 indicate bacterial growth at vacuum filters station

9. Purity drop during setteling of juice Low pH with high temperature lead inversion of sucrose the drop in pH at 70°C is near about 0.1 unit from room temp in case of mixed juice this is increases about 0.45 to . 65 unit when temperature increases from 70°C to 102 ° C the reason of drop in pH from defecated juice to clear juice is Formation of hydroxy apatite 2Ca3(Po4)2.Ca(OH)2 The proteins on longer contact with heat produce amino acids Gums and pectins also forms organic acids known as uronic acids Reducing sugar on high temperature and alkaline medium decomposes to organic acids This drop in pH and retention of juice lead inversion of sucrose

10. Purity drop during evaporation of juice During evaporation, the juice undergo to high temperature ( 115 ° C -117 ° C ) due to high temperature and alkaline medium reducing sugars decomposes to acids such as gluconic , oxalic, sacharanic acids as well as some volatile amides of amino acids decomposes to form ammonia. Low pH and high temperature of clear juice. (<7.0) leads inversion of sucrose molecule . Generally the purity drop from clear juice to syrup is near about 0.25 unit to 1.50 unit. This drop in purity increases with decrease in clear juice p H and increase in retention time during formation of clear juice to syrup.

11. Purity Drop between massecuite to molasses The purity drop between massecuite to molasses is less in case of high grade massecuite and more in low grade massecuite . This drop in purity is due to deposition of sucrose molecule from mother liquor to sugar crystal during pan boiling as well as cooling of massecuite in crystallizers. The range of purity drop between different type of massecuite (R1, Raw, B and C ) is 2 to 24 unit. This purity drop between massecuite to molasses is beneficial due to more purity drop means more sugar deposition on the sugar crystal.

12. Purity drop between massecuite to molasses depend many factors such as:- size of sugar crystal Crystal content of massecuite Boiling time of massecuite Purity of mother liquor circulation of massecuite during pan boiling viscosity of massecuite cooling of massecuite curing of massecuite

13. Purity Drop during molasses storage During storage of molasses tank the purity drop 0.10 unit to 0.25 unit in 2 to 3 month This drop in purity is due to chemical reaction in the molasses. The purity drop is increases with increase in temperature and composition of molasses (mainly water content ) it observed that annual loss 2-3 % of fermentable sugar at 30-35 ° C which is four times more on increase of 10 °C temperature

14. How to minimize purity drop 1-Cane Harvesting The time loss between cane harvesting and milling has to be minimum.it is done by efficient communication between cane department and factory site ( minimum preferably 12-24 hrs .) 2-Washing and Steaming ( A ) Hot water washing of raw juice tank,inter rack carriers at mills on regular basis sift wise . we have done every 4 hrs. in each shift ( B ) Filterate juice tank mud tanks vacuum filters washing done regular basis . we have change and clean filterate receiving tank in every shift (C ) Washing and changing of vacuum filters in every shift

15. 3-Exhaust temperature The exhaust temperature at calandria of 1 st effect evaporator maintain near about 2-3 degree plus to saturated temp 4-Control of PH in clarification Control monitoring of pH of clear juice. it should be maintain between 6.95-7.05. lower pH of clear juice causes inversion of sucrose and higher pH causes destruction of reducing sugars 5-Retention More retention causes more purity drop at low pH and high temperature

16. T his is mainly in clarifier and evaporator bodies by decreasing the retention time in clarifier and evaporator bodies we have minimize the purity drop clarifier 6-Use of Chemical (A)use of Biocides (QAC and DTC )based at mills ( B) use of Biocide at mud run off tank ( C) use of biocide in clarifier during long stoppage 7- Periodic Lab Analysis (A ) A nalysis of RS % in primary and mixed juice ( B ) A nalysis of filtrate juice ( C) Analysis of TRS of final molasses tank ( D) Regular monitoring of temperature of final molasses 8-Final molasses storage tank (A) Recirculation of final molasses in final molasses tank (B) Water spraying outside the tank to control the temperature rise of molasses

17. Loss of sugar due to purity drop Example 1-purity of mixed juice -80 2-purity of mixed juice -79 mixed juice % cane-122 % mixed juice Bx-12.50 Available sugar at purity 80 =80 X 12.50 X 122/(100X100) = 12.20 Available sugar at purity 79 =79 X 12.50 X 122/(100X100) =12.04 Loss of sugar = 12.20-12.04 =0.16 unit 1 Unit purity drop of MJ gives 0.16 Unit loss of sugar

18. Gain of sugar due to purity drop from massecuite to molasses Example Purity of M assecuite -86 Purity of M olasses -72 Available sugar at Pty 72 = = 0.58 Available sugar at Pty 71 = = 0.60 G ain of sugar = 0.60-0.58 Gain in available sugar per unit drop in molasses purity = 0.02