Performance Evaluation of Sugar Cane Milling Plant and Optimization of Process Parameters: A Case of Wonji-Shoa Sugar Factory

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Addis Ababa University


Performance assessment of WSSF and setting targets for the relatively inefficient mills to improve the efficiency and productivity is crucial. This study, focus on performance evaluation of milling plant and optimization of its process parameters. The milling plant (WSSF) performances have been evaluated in terms of its Brix juice extracted at all mill sets (5 sets). The performance of each mill was monitored by drawing juice Brix curves. From the Brix curve, the second mill front roller Brix curve overlays the back roller Brix curve this was not appropriate hence, improvement for delivery mill setting was desired. However, the reverse curve showed acceptable result. The juice and bagasse sample analysis for each mill set were analyzed then maximum loss areas were identified and the process optimization were done. The Brix free water for WSSF were done and found to be averagely 30.63 % on cane fiber. The statistical analysis were done by design expert software (6.08, version) of central composite design. The study were done by varying the effect of hydraulic pressure and imbibition water flow on the last mill for the response variables of pol and moisture % of final bagasse. The experimental design combination were held by inserting the lowest and highest values of hydraulic pressure and quantity of imbibition water flow rate for the last mill. The optimal results of pol and moisture % of bagasse were between 1.63 - 1.88% and 50.47 - 51.31% respectively, with the respective hydraulic pressure and quantity of imbibition water application of 195 - 200 kg/cm 2 3 and 71.3 - 72 m /hr. The pol and Brix extraction trends were done for how each and individual mills can perform well for a given milling season. The existing milling plant flow diagram were modified by recycling the primary juice Cush-Cush prior to the first mill and secondary juice Cush-Cush to the second mill. Using the optimum values of application of hydraulic pressure and quantity of imbibition water flow rate on the last mill, drawing juice Brix curve, Brix free water on cane fiber and recycling of respective Cush – Cush to recommended point and the optimum output of pol and moisture content of last mill bagasse which can be taken as a positive outcome to bring efficiency improvement, product maximization, for energy saving, cost reduction and increased profitability to WSSF in particular and all other sugar factories as general.



Extraction, Imbibition, Hydraulic Pressure, Moisture, Pol, Optimization, Bagasse, Milling Loss, Milling Efficiency