FORM 2
THE PATENTS ACT 1970 (39 OF 1970)
COMPLETE SPECIFICATION (See section 10)
AN IMPROVED MASSECUITE BOILING SCHEME FOR WHITE SUGAR MANUFACTURING PROCESS FOR LOWERING FINAL MOLASSES PURITY
VASANTADADA SUGAR INSTITUTE, a public trust registered under Bombay
Public Trust Act-1960 having Indian Nationality and registered office at Manjari
(Budruk) Taluka Haveli District, Pune-412307, India
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The following specification particularly describes the nature of the invention and the manner in which it is carried out.
This invention relates to improved massecuite (m/c) boiling scheme for plantation white sugar manufacturing process. The plantation white sugar manufacturing process is divided in following unit operations.
§ Juice extraction at milling station
§ Juice clarification
§ Evaporation of clear juice from 15 to 60° brix in multiple effect
evaporator
§ Syrup sulphitation
§ Massecuite boiling operations
§ Centrifugation
The juice is extracted at milling station and further clarified to obtain clear juice. The concentrated clear juice obtained from evaporator is called as syrup and is further sulphited to 5.2 to 5.4 pH. After sulphitation of syrup to a pH 5.2 to 5.4, the syrup is subjected to massecuite boiling process. The massecuite boiling essentially consists of the removal of water by evaporation in single effect vessel and crystallizing out sugar by increasing the concentration. The vessel in which this boiling and crystallization process is completed is known as vacuum pan. The function of vacuum pan is to produce and develop sugar crystals of desired size from syrup or the molasses known as mother liquor. The aims of massecuite boiling operations are as follows,
§ Separation of sucrose from it's associated impurities by forming grains from liquid phase to solid phase.
§ Separation of granular crystallizing particle by centrifugation and get maximum sugar recovery by maximum desugarisation of mother liquor.
The various technical terms used in massecuite boiling operations are as follows.
1) Syrup:
The resulting material obtained after concentration of clear juice by evaporation of excess water in the multiple effect evaporators is called as syrup.
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2) Molasses:
Molasses means the effluent obtained from centrifugals on purging or spinning the massecuite. The discharged molasses before washing of sugar layer in centrifugal is termed as heavy molasses. The discharge molasses after washing of sugar layer in centrifugal is termed as light molasses.
3) Final molasses:
The molasses obtained from the manufacturing process and from which no more sugar can be recovered economically under factory condition is called as final molasses.
4) Massecuite:
The mixture of crystals and mother liquor delivered from vacuum pan at the end of each strike is called as massecuite. This is further divided into A, B, C or D massecuites depending upon position of massecuite in process operation and syrup /molasses used to boil the massecuite. The massecuite is further classified as High-grade massecuite and Low-grade massecuites. The massecuite from which the sugar is bagged is referred as high-grade massecuites. The massecuite from which the separated sugar is either used as seed for next massecuite or melted is referred as low-grade massecuites.
5) Strike:
Each pan with full of massecuite is called as a strike.
6) Seed Magma:
It consists of low-grade sugar mingled with syrup or molasses or water and stored in crystalliser from which it is drawn in pan to start high-grade strike.
7) Exhaustibility:
Exhaustibility is the degree to which the molasses is desugarised or exhausted.
8) Brix %:
The percentage of total dissolved solids (w/w) is called as Brix % of a sample.
9) Pol %:
The commercial sucrose % (w/w) in a material is called as pol % of a sample.
10) Purity:
The ratio of pol % to Brix % is called as purity of material. Purity= pol % * 100 / Brix %
11) Recovery:
The percentage of sugar obtained per 100 cane is called as recovery.
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12) Footing:
The low grade sugar magma used for high grade massecuite boiling as source of crystals is called as footing.
The process of desugarisation cannot be completed in one step due- to various technical reasons. The massecuite obtained from the syrup is centrifuged in batch type centrifugal machines to obtain sparkling crystalline sugar, A heavy (AH) and A Light (AL) molasses. The AL molasses is recycled to A massecuite boiling. From AH molasses, next massecuite is boiled called as B massecuite. B massecuite is centrifuged in continuous centrifugal machine. After B massecuite centrifugation, the obtained B sugar is of slightly impure and used as feeding to A boiling and molasses obtained from B massecuite is called as B Heavy (BH). The BH molasses is used for C massecuite boiling. Similar to B massecuite, C massecuite is also centrifuged to obtain C fore worker (CFW) sugar and heavy molasses. The Heavy molasses obtained from C massecuite centrifugation is called as Final molasses. The CFW sugar obtained from C first centrifugation is re-centrifuged to obtain C After worker (CAW) sugar having purity above 92 and C Light (CL) molasses which is reused for C massecuite boiling.
The final molasses still contains sucrose, however, it may not further recovered considering techno economics. The purity of final molasses is a deciding factor for the efficiency of overall massecuite boiling scheme. The purity of final molasses is in the range of 32 ± 3 depending on massecuite boiling scheme adopted and its efficiency. The normal three massecuite boiling scheme is shown in figure 1.
In the prior art of three massecuite boiling scheme, the clear juice purity varies from 78 to 87. Depending upon the clear juice purity, A massecuite purity varies from 85 to 92. With increased massecuite purity, the load of sugar content in AH molasses increases. Normal AH molasses purity is in the range of 72 to 75. However, with increased A massecuite purity, the AH molasses purity also increases even up to 81. Due to this higher purity of AH molasses all other low grade massecuite and molasses purities increases resulting in the increase of final molasses purity.
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To over come this, normally sugar mills adopt three and half massecuite boiling scheme as shown in figure 2. In three and half massecuite boiling scheme, intermediate massecuite in between B and C massecuite is prepared. The massecuite % cane of intermediate massecuite is kept in the range of 2 to 4 % on cane. The intermediate massecuite may be referred as B1/B2 or C1/C2 depending on the graining practice. This massecuite boiling scheme of three and half massecuite boiling type is helpful for controlling the final molasses purity to some extent. However, it associates with number of disadvantages as follows,
§ Increase in total massecuite % cane of the order of 3-5 % on cane.
§ Decrease in plant capacity to the tune of 15 % cane due to need of additional pan boiling capacity for intermediate massecuite.
§ Increase in steam consumption as well as power consumption.
§ Higher viscosity of low grade massecuite
The object of present invention, therefore, aims to overcome the disadvantages of three massecuite boiling scheme and three and half massecuite boiling scheme mentioned in the prior art by using an improved three and half massecuite boiling scheme for reducing final molasses purity with lower massecuite % cane. The present invention provides an improved three and half massecuite boiling scheme comprising A, A2, B and C massecuite boiling for controlling final molasses purity at desired level with lower massecuite % cane.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 describes the three massecuite boiling scheme.
Figure 2 describes the three and half massecuite boiling scheme.
Figure 3 describes an improved three and half massecuite boiling scheme.
DETAILED DESCRIPTION OF THE DRAWINGS:
Accordingly, the present invention provides an improved three and half massecuite boiling scheme for high purity juices as described in detail in figure 3 which comprises syrup (1) converted to A massecuite (2) stored in A crystalliser (3) which is used as input to A massecuite centrifugation (4) whose outputs are A light (5), A heavy (6), dry seed (7), graded sugar (8) and rori (9), the A2 massecuite (10) is
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prepared from A light (5) and A heavy (6) which is stored in Crystallisers (11) which goes as input to continuous centrifugals (12) whose outputs are A2 heavy (13) and A2 sugar (14), the A2 sugar (14) goes to melter (22), B massecuite is prepared from A heavy (6) and A2 heavy (13) which is stored in Crystallisers (16) and heated in B massecuite heater (17) whose output is connected to B massecuite continuous centrifugation single (18) whose output are B heavy (19) and BFW sugar (20), the B heavy (19) and C Light (32) are used for C massecuite (24) which is stored in Crystalliser (25), which is further heated in massecuite heaters (26) and fed to C massecuite first continuous centrifugals(27) whose outputs are final molasses (28) and CFW sugar (29), the CFW sugar (29) converted to CFW magma (30) after which it is going to C second centrifugation (31) whose outputs are CAW (23) and C light (32).
Referring to figure 3, thick line blocks indicates the invention in comparison to prior art and describes the detailed improved massecuite boiling process where an intermediate massecuite A2 (10) in between A and B massecuite is prepared. The improved process consists of syrup (1) after boiling is converted into A massecuite (2) of purity above 90 in a boiling vessel under vacuum. The A massecuite is converted into A light (5) and A heavy (6) of purity 76 where maximum purity drop is achieved by adjusting different centrifuge machine (4) operational parameters. All A light (5) and partial A heavy (6) are used together under controlled condition to get purity below 84 which is a new intermediate product called A2 massecuite (10). This massecuite is stored in A2 massecuite Crystallisers (11) which is centrifuged in continuous centrifugals (12) and controlling its parameter, new products such as A2 heavy (13) having purity below 64 is obtained along with A2 sugar (14) having purity 97 + are obtained. B massecuite (15) of purity below 74 is prepared from A Heavy (6) and A2 Heavy (13) under controlled condition after which it is stored in available B Crystallisers (16). This massecuite after heating is centrifuged in B massecuite continuous centrifugation (18) to get BFW sugar (20) of purity 94 and B heavy (19) of purity below 53. C massecuite (24) having purity below 56 is prepared from B heavy (19) and C light (32) under controlled condition. After its first continuous centrifugation (27), final molasses (28) of purity below 31 along with CFW sugar (29) of purity 80 + 1 is obtained.
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In a preferred embodiment of the present invention, the purity drop from A massecuite (2) to AH molasses (13) is achieved above 14 units. This is achieved by reducing syrup separator timer at A centrifugals (4) from 15-35 seconds to 2-3 seconds and limiting first water wash timing of A centrifugals (4) to 5 seconds.
In yet another embodiment, the purity of AL molasses (5) is controlled below 85 instead of 90+ as in existing boiling scheme.
In feature of the present invention a special intermediate massecuite A2 (10) is prepared from A light (5) molasses, the purity of which is controlled below 84 by using appropriate quantity of A Heavy molasses (6) and the A2 massecuite % cane is controlled to 3 to 3.5 % on cane by controlling the A Heavy (6) molasses quantity used for A2 massecuite (10).
In still another feature of present invention A2 massecuite curing is done in continuous centrifugals (12) where, A2 Heavy (13) purity is controlled below 64 by controlling water wash quantity and A2 massecuite (10) grain size controlled below 250 micron. The A2 sugar (14) purity is maintained above 97 + and is used as footing for A massecuite.
In still another feature, A2 heavy molasses (13) is used for B massecuite boiling. The purity of B massecuite is controlled below 74 from which the B Heavy molasses purity is controlled to be below 53.
In yet another feature, the purity of C m/c is controlled below 56, which helps in reducing final molasses purity.
The advantages of the present invention are
i) Decrease in total massecuite % cane.
ii) Decrease in sugar loss in final molasses
iii) Increase in plant capacity without increasing the boiling house equipments.
iv) Decrease in steam requirement as well as power consumption.
v) Decreases the viscosity of low grade massecuite.
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The results of field trials of an improved three and half massecuite boiling scheme are given in Table 1. Table 1- Comparative results of improved three and half massecuite boiling scheme

Sr. no. Particulars Conventional threemassecuite boilingscheme data An Improved three and halfmassecuite boiling schemedata
1 Massecuite % cane
Total 53.55 49.84
A 31.79 30.27
A2 - 3.20
B 13.81 10.08
C 7.95 6.29
2 Purity drop
A massecuite to AH 11.39 14.62
A2 massecuite to A2H - 19.13
B massecuite to BH 21.38 18.42
C massecuite to Final 28.46 21.18
3 % Exhaustion
A massecuite to AH 60.60 68.10
A2 massecuite to A2H - 63.96
B massecuite to BH 64.13 55.72
C massecuite to Final 69.20 58.25
4 Massecuite Purity
A 90.66 91.04
A2 - 83.17
B 79.38 73.35
C 60.62 54.68
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We claim:
1. Improved three and half massecuite boiling scheme which comprises syrup (1)
converted to A massecuite (2) stored in A crystalliser (3) which is used as
input to A massecuite centrifugation (4) whose outputs are A light (5), A
heavy (6), dry seed (7), graded sugar (8) and rori (9), the A2 massecuite (10) is
prepared from A light (5) and A heavy (6) which is stored in Crystallisers (11)
which goes as input to continuous centrifugals (12) whose outputs are A2
heavy (13) and A2 sugar (14), the A2 sugar (14) goes to melter (22), B massecuite is prepared from A heavy (6) and A2 heavy (13) which is stored in Crystallisers (16) and heated in B massecuite heater (17) whose output is connected to B massecuite continuous centrifugation single (18) whose output are B heavy (19) and BFW sugar (20), the B heavy (19) and C Light (32) are used for C massecuite (24) which is stored in Crystalliser (25), which is further heated in massecuite heaters (26) and fed to C massecuite first continuous centrifugation (27) whose outputs are final molasses (28) and CFW sugar (29), the CFW sugar (29) converted to CFW magma (30) after which it is going to C second centrifugation (31) whose outputs are CAW (23) and C light (32).
2. A process as claimed in claim 1 comprises A, A2, B and C massecuite with A2 massecuite boiled with AL and AH molasses.
3. A process as claimed in claim 1 and 2, where an intermediate A2 massecuite is prepared for controlling the further B and C massecuite purities.
4. An improved three and half massecuite boiling scheme as fully described herein before (Claim 1- 3) with reference to figure 3.

Dated this 10th day of May 2005.
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ABSTRACT
With increased juice purity above 84, it is difficult to control final molasses purity and sugar loss in final molasses by using general massecuite boiling schemes in sugar factory. Considering this Vasantdada Sugar Institute has designed and successfully developed and field tried an Improved Three and half massecuite boiling scheme for controlling final molasses purity at desired level with lower massecuite % cane as compared to conventional massecuite boiling schemes. The improved massecuite boiling scheme consists of A, A2, B and C massecuite. The special A2 massecuite is prepared with A Light and A Heavy molasses having purity below 85.
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