Lynne Wong's PhD thesis

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1.2.2 Cane reception The cane supply arriving at a factory or a cane reception centre is first sampled at the weighbridge by means of a core-sampler (Fig 1.3) and then weighed before being unloaded on the platform for crushing. The sample is sent to the laboratory of the Cane Planters and Millers Arbitration and Control Board for analysis of Brix and pol of press juice, mass of press cake and fibre % cane, all of which are required for cane payment purposes. Cane supply Bagasse Boiler plant Live stea m Electric power plant Milling plant Mixe d juice Low pressure steam Juice heaters Clarifier Evaporator Vacuum pans Rotary filter Barometric condenser s Fres h water Liming tank Milk of lime Electric prime movers Crystallizers Centrifugals Surplus bagasse Surplus electricity Sugar Final molasses Filter cake Figure 1.2. Flow-diagram of raw sugar manufacturing process in Mauritius (Anon., 1997). 5
Figure 1.3. Cane sampling by core sampler for analysis. 1.2.3 Juice extraction The cane is first prepared by revolving knives that cut the stalks into chips which are then cut by heavy duty shredder into long fibres before entering the milling plant. The latter consists of multiple units (4 – 7) of three-roller combinations through which the crushed cane or the cellulosic fibre (bagasse) successively passes. Fresh water is sprayed on the mat of bagasse as it enters the last mill to help leach out the maximum sugar. In this context, the thin juice extracted by each mill is sprayed on the bagasse entering the previous mill. This process is termed imbibition, and the water used, imbibition or maceration water. The combined juice collected after the first mill is called mixed juice. The fibre from the last mill, the final bagasse, contains unextracted sugar and 45 – 55% moisture. Bagasse normally goes to the boiler plant as fuel to produce steam and electricity for the factory's own demand. The surplus bagasse can be used to produce electricity for the national grid. 1.2.4 Clarification and filtration The mixed juice extracted from the cane is acidic in nature, of pH about 5.2; it consists of a solution of sucrose mixed with soluble and insoluble impurities. The clarification (or defecation) process removes most of the turbid impurities by the action of heat and lime. The mixed juice is heated, in most cases, to about 75 °C, and the juice pH is changed from 6
Page 1 and 2: THE BRIX-FREE WATER CAPACITY AND SO
Page 3 and 4: dissolved and hydrated waters, and
Page 5 and 6: ACKNOWLEDGEMENTS I am particularly
Page 7 and 8: Page 1.5 THE DELETERIOUS EFFECTS OF
Page 9 and 10: Page 2.2 THE PHENOMENON OF BRIX-FRE
Page 11 and 12: Page 3.4.3.3 Cane tops 83 3.4.4 Cha
Page 13 and 14: 4.3.3 Temperature at which Brix-fre
Page 15 and 16: 4.6.1 Materials 143 4.6.1.1 Samples
Page 17 and 18: CHAPTER 6. PROPERTIES OF THE SORBED
Page 19 and 20: APPENDIX 3. CALCULATIONS LEADING TO
Page 21 and 22: LIST OF FIGURES Page Figure 1.1. Fi
Page 23 and 24: Figure 3.1. Glucose and fructose an
Page 25 and 26: Figure 5.11. Residual plots for the
Page 27 and 28: total adsorbed water (m) and the pr
Page 29 and 30: Table 2.18. Moisture content in sug
Page 31 and 32: Page Table 4.4. Results of the dete
Page 33 and 34: Page Table 4.24. Analysis of varian
Page 35 and 36: Page Table 5.13. Table 5.14. Equili
Page 37 and 38: Table 6.3. Heat of sorption of the
Page 39 and 40: GLOSSARY OF TERMS Absorption is the
Page 41 and 42: Filterability of a raw sugar is mea
Page 43 and 44: Sorption is the generic term used w
Page 45 and 46: LIST OF MAIN SYMBOLS Symbol Descrip
Page 47 and 48: s c s Slope of Caurie I isotherm pl
Page 49 and 50: number of 255, and cane land covere
Page 51: Nouvelle Mon In Trésor ustrie and
Page 55 and 56: In Mauritius, most of the sugar fac
Page 57 and 58: are: cane tops, dry and green leave
Page 59 and 60: 1.4 TRENDS IN CANE QUALITY RECEIVED
Page 61 and 62: campaign was launched to encourage
Page 63 and 64: The level of extraneous matter in c
Page 65 and 66: In Australia (Cargill, 1976), cane
Page 67 and 68: The effect of soil on factory perfo
Page 69 and 70: leaves increased the level of impur
Page 71 and 72: • From 1976 to 1980, when the pro
Page 73 and 74: Clerget purity of molasses 40 Clerg
Page 75 and 76: CHAPTER 2. IMPACT OF EXTRANEOUS MAT
Page 77 and 78: Since the extrapolated purity of mo
Page 79 and 80: Figure 2.1. Jeffco cutter grinder.
Page 81 and 82: 2.1.4 Results The analytical result
Page 83 and 84: Table 2.3. Analytical results of re
Page 85 and 86: Table 2.5. Composition of dry trash
Page 87 and 88: Table 2.7. Predicted factory perfor
Page 89 and 90: Boiling house recovery 91.0 89.8 89
Page 91 and 92: 0 5 10 15 20 % EM in cane y = 0.572
Page 93 and 94: % EM in cane 0 5 10 15 20 0 -2 -4 -
Page 95 and 96: 1 y = 0.020 (% D) R 2 = 1.00 = 0.03
Page 97 and 98: % EM in cane 0 5 10 15 20 0 -2 y =
Page 99 and 100: esulting in 0.015 unit sucrose loss
Page 101 and 102: 2.2.1 Experimental procedure Cane m
Page 103 and 104:
filter paper, rejecting the first f
Page 105 and 106:
Table 2.9. Effect of increased addi
Page 107 and 108:
Table 2.11. Effect of increased add
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Table 2.13. Effect of increased add
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various components such as stalk fi
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in the presence of dry leaves, if c
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Table 2.17. Moisture content in sug
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CHAPTER 3. SEPARATION OF THE SUGAR
Page 119 and 120:
Table 3.1. It can be seen that the
Page 121 and 122:
Table 3.2. Fibrous physical composi
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R 579 R 570 M 1557/70 M 1400/86 74
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loosen the fibre. The woody core is
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agitate the mixture in the pot, and
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Figure 3.7. Custom-built fibre-pith
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The extraction of fibres starting f
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pre-treatment in a Jeffco cutter-gr
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Figure 3.19. Stalk cake washed free
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not have many dry leaves attached t
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Table 3.5. Masses of cane samples a
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Table 3.7. Masses of cane samples a
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Table 3.9. Masses of cane component
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3 57.6 126.3 23.7 97.2 31.1 53.8 11
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Table 3.12. Material loss (%) from
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3.5.3 Fibre/pith ratios in cane com
Page 151 and 152:
Table 3.15. Effect of extraneous ma
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Snow (1974) investigated the season
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from Figure 2.9 that the change in
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Table 3.18. Fibre % cane results by
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110
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(a). Dry leaf (b). Green leaf (c).
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dry fibre, or a factor, is used in
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Steuerwald (1912) applied sucrose s
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solution/fibre ratio was lowered fr
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leave some residual moisture on the
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instead of 150 g of 10° Brix sucro
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Table 4.2. Determination of Brix-fr
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Table 4.3. Comparison of Brix-free
Page 177 and 178:
Table 4.4. Results of the determina
Page 179 and 180:
In order to test for homogeneity of
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Table 4.7. Results of the repeat de
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The experiment was repeated with th
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e any residual moisture in the samp
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By means of the same technique, Won
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was still hot. Since the filter was
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value determined could be corrected
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Qin and White’s finding was confi
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A sample size of 3.5 g with 75 g co
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Figure 4.4. Fibre samples drying in
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- One large fibre sample (rind) of
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Table 4.18. Brix-free water values/
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Table 4.20. Brix-free water values/
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4.7.3 Statistical analysis It is es
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Table 4.23. Analysis of variance (B
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pointing out that at 52 weeks old,
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The crop of R 570 sampled in 2001 w
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4.7.4. Estimated Brix-free water co
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The main difference in the two sets
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Table 4.27. Predicted Brix-free wat
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4.8 SUMMARY AND CONCLUSIONS An anal
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component parts, and verify the Bri
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3) Thermodynamic, water in equilibr
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Langmuir (1916, 1917, 1918) propose
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to determine the moisture sorption
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Table 5.1. Some commonly used isoth
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Lomauro et al. (1985) found that wi
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and on agricultural products such a
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Bruijn (1963) studied the mass incr
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After measuring the EMC of dry corn
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approached, that is, either by adso
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Table 5.4. Water activity (a w ) of
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5.6.3 Procedure to determine equili
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5.6.4 Results and discussion An exa
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Table 5.8. Equilibrium moisture con
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Table 5.10. Equilibrium moisture co
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Table 5.12. Equilibrium moisture co
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30 o C 45 o C 55 o C 60 o C Water w
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m/m of 96% activity, a w (g/100g dr
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vaporisation generally decreases fr
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30 o C isotherm 45 o C isotherm 55
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4 0 Stalk fibre 5 0 Stalk pith 5 0
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5.6.4.4 Fitting of sorption models
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Table 5.19. Parameters of the sorpt
Page 267 and 268:
Page 269 and 270:
Page 271 and 272:
Page 273 and 274:
Page 275 and 276:
Modified GAB Kuhn Iglesias - Chirif
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Table 5.28. Classification of resid
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Stalk fibre Stalk pith Rind fibre 4
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5.6.4.5 Calculated EMC values of re
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Table 5.30. Calculated equilibrium
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m/m of 96% Table 5.32. Calculated e
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Table 5.33. Parameters of the Hailw
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CHAPTER 6. PROPERTIES OF THE SORBED
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where m is the equilibrium moisture
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Page 295 and 296:
Page 297 and 298:
6.2 THE NUMBER OF ADSORBED MONOLAYE
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6.3 TOTAL SOLID SURFACE AREA AVAILA
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Thus, for each cane component of ea
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abscissa. For each moisture level (
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Page 307 and 308:
A similar procedure was followed to
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10 0 Stalk fibre Stalk pith Rind fi
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Moreover, if T β > T hm the proces
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Table 6.5. Characteristic parameter
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Binding energy/kJ (kg mol) -1 2 0 0
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6.8 CALCULATION OF BOUND WATER AND
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The values of K 1 , K 2 and W were
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Table 6.7. Separation of the total
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Table 6.7. (Contd.) Sample 30 o C 4
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3 0 S talk fibre 4 0 Stalk pith 3 0
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3 0 Reconstituted cane at 30 o C 3
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when water is added to dry wood, wh
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It is evident that in some cases ma
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The number of adsorbed monolayers,
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Data in Tables 2.9 and 2.11 show th
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particular fibre is systematically
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Anon. (1985b). Laboratory manual fo
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Blanchi R.H. and A.G. Keller (1952)
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Day D.L. and G.L. Nelson (1965). De
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Heyrovsky J. (1970). Determination
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Kuhn I.J. (1964). A new theoretical
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Madamba P.S., R.H. Driscoll and K.A
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Prinsen Geerligs, H.C. (1897). Stud
Page 353 and 354:
Sing K.S.W., D.H. Everett, R.A.W. H
Page 355 and 356:
Van der Pol C., C.M. Young and K. D
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Lynne Wong's PhD thesis

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