A study of factors contributing to molasses formation in sugar manufacturing atTriveni Engineering & Industries Ltd.
Disclaimer - These papers/articles/ppts written by TEIL officials may have appeared in various journals/proceedings etc.
ByRajesh Singh
Sr. Manager(QC)Triveni Engineering & Industries Ltd.
Sugar Unit : Khatauli & Deoband . UP. INDIATechnical committee member-BIS (FAD2)
National committee member-ICUMSA
INTRODUCTION-TRIVENI ENGINEERING & INDUSTRIES LTD(SUGAR BUSINESS)
• Triveni Engineering & Industries Ltd- 7 sugar producing units situated in U.P
• 5 Double sulphitation & 2 back end refineries
• Total Cane crushing capacity- 61000 TCD
• Back end refinery (Khatauli) – 1200 TPD
• Back end refinery (Sabitgarh) - 600 TPD
INTRODUCTION-MOLASSES
• The term “molasses "is applied to the final effluent obtained in the preparation of sugar by repeated crystallization.
• The quantity of molasses obtained and its quality(composition) provides information about the nature of sugarcane and the processing in the sugar factory, such as efficiency of juice clarification, method of crystallization during boiling and the separation of the sugar crystals from the low-grade massecuite.
INTRODUCTION-MOLASSES
• In white sugar production the yield of molasses is in neighborhood of 4%-4.50%(Phosphotation ) and 4.75%-5.25%(sulphitation) of sugarcane .
• With an average sugar content in the cane of 12 to 12.50% only 10.25 to 10.50% of the sugar is recovered as a commercial product.
• As an average 8 to 10 % sugar of total sugar of cane goes into the molasses when sugar is produced.
INTRODUCTION
• This paper is an attempt made to understand the formation of molasses and to find out a way forward to reduce its formation to a practical level.
• In order to optimize molasses formation and increase crystallization, it is necessary to understand the mechanism and factors responsible for molasses formation during sugar production from sugar cane.
EARLIER INVESTIGATIONS AND THEORY OF MOLASSES FORMATION
• Theory of molasses formation:• The Mechanical Theory.• Chemical Molasses Theory.• Helderman was of the opinion that every molasses can crystallize out Still
further on continued evaporation; only the velocity of crystallization and the size of the crystals become very much
• reduced, so that the last crystals may be only visible under the microscope.
EARLIER INVESTIGATIONS: REDUCING SUGAR & MOLASSES
• Gunning has said that glucose renders a certain amount of sucrose uncrystallizable. Pellet put down the melassigenic coefficient of glucose as 0.60. Flourens allows various values for that figure, fluctuating between 0.30 and 1.0, whilst Degener mentioned having found glucose to possess no melassigenic power of its own, but able to transform sucrose into invert sugar by the action of its acid products of decomposition. In that connection Pellet also mentioned two distinct sources of molasses-forming by glucose, namely, one as a consequence of the inverting action of glucose, which he calculates as 0.16, and further the pure melassigenic power, at a value of 0.60.
EARLIER INVESTIGATIONS: NON SUGARS & MOLASSES
• Geerling added that the quantity of molasses and the loss of sugar depend, on the amount of non-sugar in the juice, and impure (juice with higher non-sugar) juice will yield more molasses than a pure one.
EARLIER INVESTIGATIONS: GUMMY SUBSTANCES & MOLASSES:
• While investigating composition of cane molasses Geerling observed that gummy substances (5-6%), decomposition products of reducing sugar, increases the viscosity in the process and stated that massecuites should be as little viscous as possible in order to enable it to be easily separated from the crystals without much washing in the centrifugals.
INVESTIGATION CARRIED OUT AT SUGAR UNIT KHATAULI AND DISCUSSIONS:
• With the above back ground and understanding the vital role of Reducing sugar and gummy substances (Dextran in particular) in molasses formation, a study was initiated at sugar unit – Khatauli, during season 2014-15, to analyze Reducing sugar in all major cane varieties in supply ,Reducing sugar during various stages of sugar processing, Dextran in fresh cane ,Dextran in Primary Juice, ambient temperature , early variety supply ,and all above factors were correlated with Molasses production.
INVESTIGATION CARRIED OUT AT SUGAR UNIT KHATAULI AND DISCUSSIONS:
• Cane supply zones: 8 Zones(Distant as well as near)• Sugarcane varieties:• Co 238, Co 98014, CoS 8436 - Early maturing (Highly sugared varieties)• CoJ 88- Improved variety (Highly sugared variety)• CoS 767-Mid maturing variety(Average sugared variety)• CoSe 92423-Late maturing variety(Poor sugared variety)• Co 1148 - Reject variety (Poor sugared variety)• Fresh cane samples (Approximately 2500 samples) from field, of ratoon cane during month
- December, Ratoon and Plant cane during month –February, & Plant cane during months –March & April were analyzed.
RATOON (RIPENED) ANALYSES OF ALL MAJOR SUGAR CANE VARIETIES (DEC-2014)
Variety Brix Pol PurityPol % Cane
RS % /100brix
RS%/100BX %
Bx%Juice
Dextra n in ppm
Dextra n/100 Bx
CO 0238
20.34 18.26 89.79 13.151.83
9.0083 408
CoJ 88 20.94 18.70 89.29 13.46 0.99 4.73 82 392CO 98014
19.65 17.45 88.82 12.56 2.94 14.96 94 478
Co 1148 17.45 14.47 82.94 9.90 8.92 51.12 99 567
CoS 767 18.55 15.88 85.64 11.15 3.50 18.87 70 377
CoS 767 18.55 15.98 86.16 11.22 4.01 21.62 102 550
RATOON (RIPENED) & PLANT (ON GOING RIPENING) ANALYSIS OF ALL MAJOR SUGAR CANE VARIETIES (FEB- 2015)
Variety Brix Pol Purity Pol % Cane RS % /100 brix
RS % / 100Brix%of
Bx%Juic eDextran inppm
Dextran/100 Bx
CoJ- 88(Ratoon)
20.57 18.47 89.80 13.30 1.20 5.83 84 408
CoJ- 88(Plant)
19.48 17.26 88.60 12.42 2.07 10.63 89 457
CO - 0238(Ratoon)
20.07 18.03 89.84 12.98 1.51 7.52 93 463
CO - 0238(Plant)
19.38 17.21 88.85 12.39 2.24 11.56 96 495
CO - 98014(Ratoon)
19.58 17.44 89.10 12.56 1.61 8.22 105 536
CO - 98014(Plant)
18.58 16.50 88.82 11.88 3.68 19.81 113 608
Co-1148(Ratoon)
17.18 14.11 82.14 9.65 6.58 38.30 97 565
Co-1148(Plant)
16.78 13.40 79.88 9.17 11.92 71.04 102 608
Cos-767(Ratoon)
18.48 15.83 85.67 11.11 3.13 16.94 96 519
Cos-767(Plant)
17.58 14.82 84.31 10.40 5.38 30.60 97 552
FRESH PLANT (RIPENED) ANALYSIS OF ALL MAJOR SUGAR CANE VARIETIES (MARCH- 2015)
Variety Brix Pol PurityPol % Cane
RS % /100 brix
RS % /100
Brix%of Bx%Juice
Dextran in ppm
Dextran/100 Bx
Co 023821.11 18.70 88.60
13.47 0.86 4.07 152 720
CoJ 88
20.51 18.32 89.31 13.19 0.92 4.49 160 780
Co 98014
20.41 18.23 89.32 13.13 0.94 4.61 154 755
CoS 767
19.81 17.07 86.19 11.98 1.33 6.71 157 793COS 8436
22.62 20.35 89.96 14.65 1.05 4.64 152 672CO-1148
19.12 16.63 86.98 11.31 3.34 17.47 160 837CoSe-92423
20.32 17.88 87.99 12.16 3.18 15.65 185 910
FRESH PLANT (RIPENED) ANALYSIS OF ALL MAJOR SUGAR CANE VARIETIES (APRIL-2015)
Variety Brix Pol Purity Pol % Cane
RS % /100 Brix
RS % /100 Brix% of Brix%Juic e
Dextran in ppm
Dextran/100 Bx
Co-0238 22.70 20.27 89.31 14.601.21 5.33 160 705
Co-0238 22.60 20.11 89.00 14.481.26 5.58 154 681
Coj-88 22.00 19.41 88.25 13.981.39 6.32 165 750
Coj-88 22.80 20.19 88.56 14.541.27 5.57 162 711
Cos-8436 22.80 20.26 88.88 14.591.34 5.88 154 675
Cos-8436 22.10 19.36 87.60 13.941.40 6.33 171 774
Cos-767 19.99 17.09 85.53 12.002.17 10.86 181 905
Co-1148 21.00 18.01 85.75 12.643.84 18.29 171 814
EARLY MATURING HIGHLY SUGARED VARIETIES & MOLASSES% CANE
REDUCING SUGAR STUDY DURING PROCESSING
Analysis: 28.11.14 20.12.14 13.01.15 12.02.15 12.03.15 25.04.15
PrimaryJuice
5.857.67 7.25 6.35 6.44 7.68
Mixed Juice6.34
8.08 7.58 6.66 6.80 8.08
Oliver Filtrate Juice
7.558.63 7.99 7.21 7.53 8.53
Clear Juice6.28
8.23 7.60 6.76 6.87 8.13
Semi Kestner6.36
8.39 7.83 6.92 6.97 8.21
V.Cell6.64
8.53 7.98 7.15 7.19 8.37
Deficated Syrup
6.928.65 8.15 7.44 7.66 8.86
Raw Melt0.32
0.21 0.24 0.21 0.19 0.23
Clear Melt0.33
0.22 0.25 0.23 0.21 0.24
Fine Liquor0.35
0.23 0.26 0.24 0.22 0.25
Final Molasses 19.45 25.37 24.54 24.10 21.48 25.39
REDUCING SUGAR ANALYSIS OF PROCESS
Observations: 28.11.14 20.12.14 13.01.15 12.02.15 12.03.15 25.04.15
BX%Primary Juice 17.5616.99 16.14 17.46 18.26 18.79
Reducing sugar in Primary
Juice% Primaryjuice Brix 33.31 45.12 44.95 36.38 35.25 40.86
% Increase Primaryjuice to Mixed
juice 8.38 5.39 4.48 4.90 5.63 5.27
% Increase Mixedjuice to Clear
Juice -0.95 1.93 0.22 1.40 1.00 0.56
%Increase Clearjuice to
Semikestner 1.27 1.83 3.03 2.42 1.54 0.98
INFERENCE OF REDUCING SUGAR STUDY
• Reducing sugar in Primary juice-Cane freshness ,maturity, high in sugar
• Reducing sugar rise during milling- Sanitary conditions at mills & recirculation.
• Reducing sugar rise during clarification- Heat & chemical addition.
• Reducing sugar rise during evaporation-Heat & fluctuation in crush rate.
• Reducing sugar rise during melt clarification-Concentration & chemical addition.
• Reducing sugar rise during ion exchange – Concentration & retention.
REDUCING SUGAR ANALYSIS OF PROCESS
Observations: 28.11.14 20.12.14 13.01.15 12.02.15 12.03.15 25.04.15
%Increase Semikestner to
Vapour cell 4.40 1.71 1.96 3.38 3.08 1.94
%Increase in Evaporation 10.19 5.08 7.32 10.07 11.57 9.00
%Increase in Melt clarification
3.13 7.00 3.62 12.04 10.85 4.45
%Increase in IonExchange 6.06 4.02 5.03 3.57 5.18 4.78
REDUCING SUGAR IN PRIMARY JUICE & MOLASSES% CANE
REDUCING SUGAR OF PROCESS STREAM & MOLASSES% CANE
0.00
10.00
20.00
30.00
40.00
50.00
60.00
70.00
Nov
Dec
Jan
Feb
March
Apr
Mol%cane
RS(final
Mol)
RS(Def
SYR)
RS(Cl.J)
RS(MJ)
RS(PJ)
DEXTRAN CONTENT & MOLASSES% CANE
AMBIENT TEMPERATURE & MOLASSES% CANE
FACTORS AFFECTING MOLASSES FORMATION
MonthHighly
sugaredvariety
%
Pol % Rec % Mol % Dextranin ppm
RS % inP.Juice
Maxtemp
Nov
57.944 11.46 9.37 4.47 277 5.85 29.19
Dec
45.71 10.87 8.89 4.99 281 6.46 22.04
Jan
18.831 10.59 8.53 5.29 336 7.03 17.94
Feb35.292 11.70 9.74 5.01 397 5.70 27.11
Mar
46.177 12.12 10.04 5.11 428 6.18 30.27
April
28.446 11.83 9.50 5.56 504 6.65 35.20
FACTORS AFFECTING MOLASSES FORMATION
Early maturing cane supply and molasses formation.
Reducing sugar%PJ content and molasses formation.
Dextran and molasses formation.
Ambient Temperature & molasses formation.
Non-sugar & Molasses formation
CAO STUDY IN MIXED JUICE AND CLEAR JUICE
Mixed juice Clear juice
Month CaO mg/Ltr CaO mg/LtrCaO mg/Ltr % Rise
from Mixed Juice Mol% cane
Nov 800 1100 37.50 4.47
Dec 950 1220 32.95 4.99
Jan 950 1190 21.18 5.29
Feb 1040 1330 27.25 5.01
Mar 1030 1280 25.57 5.11
April 1020 1300 27.06 5.56
%CAO RISE FROM MJ TO CLEAR JUICE AND MOLASSES% CANE
15.00
10.00
5.00
0.00
20.00
45.00
40.00
35.00
30.00
25.00
Nov Dec Jan Feb March Apr
Mol%cane
%Cao rise from MJ to Cl.Juice
MIXED JUICE PURITIES & MOLASSES% CANE OF TRIVENI GROUP SUGAR UNITS
81.74 79.94
79.51
80.91
81.76 80.1
0
4.26 4.87 4.46 4.77 4.37 4.62 5.05
78.39
77.50
78.63
77.51
82.3178.87
78.66
77.19
5.17
5.28 4.80 5.30 5.04 4.88 4.86
0
30
20
10
40
50
70
60
80
90
Khatauli Deoband
Sabitgarh
Ramkola
CHP RNG MNP
Mixed juice Purity(15-
16) Molasses%cane(15-
16) Mixed juice
purity(14-15)
Molasses%cane(14-15)
MIXED JUICE PURITIES OF TRIVENIGROUP SUGAR UNITS
81.74
79.94
79.51
80.91
82.31
81.76
80.10
78.39
77.50
78.63
77.51
78.8778.66
77.19
77
76
75
74
78
79
80
81
82
83
Khatauli Deoband Sabitgarh Ramkola CHP RNG MNP
Mixed juice Purity(15-16)
Mixed juice purity(14-15)
MOLASSES% CANE OF TRIVENI GROUPSUGAR UNITS(SEASONS 14-15 & 15-16)
4.26
4.87
4.46
4.77
4.374.62
5.05
5.17
5.28
4.80
5.30 5.04
4.88 4.86
0
1
2
3
4
5
6
Khatauli Deoband
Sabitgarh
Ramkola
CHP RNG MNP
Molasses%cane(15-16)
Molasses%cane(14-15)
MOLASSES% CANE OF REFINED SUGAR PRODUCING UNITS OF UP
4.264.46
4.183.95
4.53
3.96
4.89
4.48 4.56 4.60
5.17
4.80 4.89
4.39
5.21
4.18
4.68 4.74.85
5.07
0
1
2
3
4
5
6
KHT SBT
Asmoli Naglamal
Kinoni Simbhaoli
Rozagaon
Libberhedi
Shermau
Khaikheri
Mol%cane(15-16)
Mol%cane(14-15)
CONCLUSION
• Propagation of varieties high in sugar, low in RS and less susceptible of post harvestdeterioration/extreme weather condition, like CoJ 88 ,Co 98014,Co0238. It was observed that on account of lesser Reducing Sugar at the same age crop variety CoJ 88 is having a less molasses formation tendency among all highly sugared & early maturingsugarcane varieties.
• RS in Primary juice should not exceed 25% of its Brix.
• Dextran in Sugar cane max-100-150 ppm.
• RS Variation not more than 5% in any unit operation.
• Cao rise from Mixed juice to clear juice –maximum 50% in sulphitation and 25 % +- 5% inphosphotation.
• Sugar crystallization can be improved if all factors responsible for molasses formation arewell taken care from cane management up to process management.
ACKNOWLEDGEMENT
• I sincerely express my gratitude to our CMD Shri D.M.Sawhney and Vice Chairman & Managing Director Shri Tarun Sawhney for theirencouragement, interest in the subject and allowing me to publish &present this paper. My thanks are also due to Dr.Ashok Kumar, VP(S), Sugar Unit-Khatauli & Shri.D.N.Mishra VP(S) Sugar unit Deoband for theirencouragement and valuable guidance.
THANK YOU
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