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Title: Evaluation and optimization of process conditions for Lime saccharate clarification in the manufacture of plantation white sugar:The case of Metahara sugar Factory
???metadata.dc.contributor.*???: Gizachew Shiferaw (Eng.)
Abayneh, Bazezew
Keywords: Sugar;Clarification;Lime saccharate;Optimization
Issue Date: Jun-2011
Publisher: AAU
Abstract: This paper analyses the possibility to adopt lime saccharate clarification in Metahara Sugar Factory and also tries to find optimum process conditions for better juice purification. Mixed juice samples of 5 l each were taken from weighed mixed juice pumps’ return line and pretreated so as to be used for settling test. To get the targeted P2O5 content in juice, calculated amount of phosphoric acid was added to the sample and subjected to heating to 750C.Then, the pH was raised to the pH of 8.5-9.5 by the addition of lime or lime saccharate, heated to the boiling point. The prepared sample was taken and poured in to the 1000 ml graduated cylinder containing flocculant (separan).The required parameters were determined from the clarified juice sample. The data obtained from the comparative experiments were subjected to statistical analysis using design expert software whereby the significance was set at 5% level. The result of the experiment has shown that mixed juice sample from different combinations of cane varieties did not show any significant variation in quality parameters at 5% significance level. At P2O5 content of 300ppm and separan concentration of 3ppm, the upper limit of the preliming pH of 9.5 gave better results for lime saccharate such as purity of 84.7%, CaO of 936ppm, and turbidity of 477TU. But, when the P2O5 content was increased to 350ppm, at separan concentration at 3 ppm, the mid value, pH of 9, gave better results i.e, purity of 84.8%, turbidity of 163 Tu, settling rate of 10 cm/min, reducing content of 0.52%. On the other hand, when the P2O5 content was raised to 350 ppm with a separan concentration lowered to 1ppm, the lower limit value of PH=8.5 gave better values. Furthermore, analysis of data of both treatments using the design expert software has proved to be significant for all the parameters except that of CaO. The analysis had also shown that the optimum process parameters of clarification were identified to be pH=8.87, P2O5=321.15 and separan concentration of 3 ppm, which gave acceptable values of the response variables considered. Using the optimum pH, evaluation of the chemical consumption revealed that there is about 71% reduction in lime consumption which can be taken as a positive outcome to bring cost reduction and increased profitability to Metahara Sugar Factory in particular and all other sugar factories in general.
Appears in Collections:Thesis - Food Engineering

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