Sugar boiling

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Part of The Sugar Cane Planter

Title: Sugar boiling
Language: English
Year: 1937
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Fulltext: 38 THE SUGAR CANE PLANTER (DECEMBER, 1937 . Sorne Boiling Notes on Systems Sugar By COLIN W. WADDELL Probably the last word concerning the art of sugar boiling never will be written, because it is beset with so many variables. Sorne notes and conclusions are here recorded in the hope that they may prove of interest or value to boilinghouse men who are faced with similar problems elsewhere. At the beginning of the 1936-37 milling season many factories in the Philippine Islands were called upon to produce raw sugar of about 1 per cent. higher pol. than had been the practice f ormerly, without any additional equipment, and with a rather venerable array of past capacity and recovery records to be met or improved upon. The increased load at pan and centrifuga! stations sharply demonstrated the importance of selecting a "boiling system" best adapted to local conditions. Weekly factory runs were made with the following:~ (a) Three Massecuite: in-b~d "A", Straight "B" and "C" A : 15 % Seed Magma, 70 % Syrup, 15 % AMolasses. B: 12 % Seed Magma, 21 % Syrup, 67 % .4.Molasses. C: 9 % Syrup, 91 % B-Molasses. ( b) Four Massecuite : straight.A: 10% Seed Magma, 90% Syrup. B: 10% Seed Magma, 63% Syrup, 27% AMolasses. C: 107a Seed Magma, 28% Syrup, 62% BMolasses. D: 9% Syrup, 91 % C-Molasses. (e) Three Massecuite : in-boiled "A" and "B", straight "C" A: 10% Seed Magma, 76% Syrup, 14% AMolasses. · B: 10% Seed Magma, 30% Syrup, 46% AMolasses, 14 % B-Molasses. C: 9 % Syrup, 91 % B-Molasses. (d) Three Massecuite : in-boiled all Massecuites: A: 10% Seed Magma, 76% Syrup, 14'/a AMolasses. B : 1 O% Seed Magma, 43 % Syrup, 38 % AMolasses, 9 % B-Molasses. C: 8% Syrup, 79% B-Molasses, 13% C or Final Molasses. (e) Modified Two-boiling System :A : 10 % Seed Magma, 90 % Syrup ( Only 4 strikes per day) . · B : 10 % Seed Magma, 44 % Syrup, 10 % AMolasses, 36 % B-Molasses. C: 9 % Syrup, 91 7o B-Molasses. (f) Three Massecuite : straight :A : 10 <fo Seed Magma, 90 % Syrup. B: 10% Seed Magma, 21 % Syrup, 69% AMolasses. C: 9 % Syrup, 91 % B-Molasses. A comparison of average factory results is shown in Graph No. 1, and equipment-production relationships at the Central under trial in Table 1 (in metric to ns) . TABLE l. EQUIPMENT-PRODUCTION RELATION. SHIPS. Per ton Per ton Per ton Per ton Dry Cane Sugar Fin. Mol. Non Suc. per hour per hour per hour per hour boiling boiling boiling boiling time. time. time. time. Pans, H.S., sq. ft. 42.5 350 2275 1514 Crystallizers, cub. ft. 109 .5 903 5868 3904 H.G. Centrifugals Screen area, sq. ft. 1.87 15.4 100 67 L.G. Centrifugals Screen area, sq. ft. 4.92 40.6 263 176 CONCLUSION. It will be observed that so-called "straight" boiling methods were compared with various "in-boiling" · methods in a factory which was inclined to be short of pan and centrifuga! capacity. Results point favourably towards system (e) Three Massecuite, in-boiled "A" and "B'', straight "C". In operation, this system consists of "toppingoff" both the "A" and the "B" Massecuites with 14 per cent. of "A" and "B" Molasses respectively, regardless of initial syrup purity. Variations in syrup purity, and consequently the "A" Molasses purity, are taken care of by varying the proportion of these in the "B" Massecuite, not by altering the amount of Iow purity molasses "inboiled." · COMMENTS. In the analysis of data pertaining to factory scale comparisons like the above, many factors have to be considered, and we find it impossible to give each one its true value in relation to the problem as a whole; for example: "Tons sugar per Boiling Hour" may be increased at the expense of another like "Boiling House Recovery," regardless of the boiling system used. The best simple figure for comparing the merits of one boiling system with another is "Volume of Total Massecuite Boiled per unit weight of Dry NonSucrose entering in Syrup. In almost any cane sugar producing country we will find sorne staunch advocates of the socalled "straight" boiling system, while others produce equally sound evidence in favour of "in· boiling." The question of re-circulation of impurities can be calculated accurately and invariably favours "straight" boi1>1g. We may also reasonably expect that if we recirculate impurities, as in the case of an "inboiling" system, we will increase the volume of massecuite boiled per ton sugar produced, exPlease Patronize Our Advertisers DECEMBER, 1937] THE SUGAR CANE PLANTER 39 posing the sucrose to more inversion, besides decomposing sorne of the impurities already present with a combined effect of increasing the "stickness" of massecuites, which in turn will reduce capacity and increase steam consumption. However no rule can ever be expected to fit all factories equally, due to differences in equipmentproduction relationships and variations in impurities present. A factory with ample and efficient pan and centrifuga} capacity, or where the nature of impurities does not seriously retard crystallization rates, as a rule will find "straight" boiling best; on the other hand, a factory which is forced to keep pans boiling under full steam pressure throughout the entire cycle may materially benefit from a little "topping-off" with low purity molasses. An explanation for this may be based upon two facts : ( 1) A crystal of sucrose grows fas ter in a high purity mother-liquor than in a low one, other conditions being the same; (2) the rate of crystal growth is approximately proportional to the crystal surface area exposed to the motherliquor. At a factory which is short of pan capacity and has to force evaporation rates to the maximum throughout, by selecting an "in-boiling" system we can build up a greater proportion of the strike on high purity material with its fast crystallizing rate, and thus avoid false grain formation in spite of the fast evaporation rate. Then, towards the end of the. strike, when it is necessary to take on the low purity molasses in order to finish at the required massecuite purity, we have already established a large crystal surface a.rea which compensates, to sorne extent, the reducing rate of crystal growth and enables the rapid evaporation rate to be continued without danger of false grain. SUMMARY. (1) A comparison of average weekly results from the operation of six different boiling systems in a factory which was rather short of pan and centrifuga} equipm~nt for the quantity and nature of impurities handled, resulted in the conclusion that faster and better work was done when commercial sugar massecuites were "topped-off" with 10 to 15 per cent. of molasses of the same grade of massecuite, than when any of the so-called "straight" methods were used. (2) Attention is drawn to the importance of taking numerous factors into consideration befare passing judgment upon any particular system, and support given to the importance of "volume of total massecuite boiled per unit weight of dry non-sucrose entering in syrup." The system which under existing conditions at any factory, reduces this figure most will almost invariably give the best overall results, regardless of whether this is achieved by "straight or by "inboiling" systems. (3) An explanation is submitted for the poorer recoveries obtained at a factory where pans had to be forced to maximum evaporation rates, when massecuites were boiled "straight" than when a little "in-boiling" was practised.- ( The International Sugar Journal). AZUCAREROS PREEMINENTES Don MANUEL URQUICO Distinguido azucarero de Tarlac y una de las columnas mas sólidas .de la industria del azúcar en Luzon, nació en Tárlac, Tárlac el 28 de abril de 1883. Cursó sus primeros estudios en el Colegio de Letrán, tomando luego algunos principios de derecho en la Escuela de Derecho de Manila. Es actualmente director de la Central Azucarera de Tarlac, al mismo tiempo que plantador progresivo y Presidente de la Asociación de Plantadores de Tárlac. Como plantador y azúcarero activo abriga temores por el futuro de la industria ante la perspectiva de una vida independiente atada, sin embargo, con fuertes cordeles de limitaciones e impuestos; pero cree que tal vez se pueda salvarla de un destino nebuloso con los esfuerzos de un sólido frente de los azúcareros que con enérgica batalla logre para ella mejor porvenir. Sobre el jornal mínimo opina que la clase obrera también necesita del Nuevo Trato, pero, que el tipo de jornal necesariamente varíe según las circunstancias. Las plantaciones y fábricas en la provincia de Tárlac están dispuestas a elevar los jornales hasta donde sea menester siempre y cuando sea razonable. Como plantador y centralista el Sr. Urquico es un colaborador activo en todas las empresas y movimientos que tiendan no sólo a desarrollar la industria azúcarera sino más aún a contrarrestar los obstáculos que, puedan salir al paso, en forma de legislaciones onerosas para su futuro. Please Patronize Our Ad·vertisers