Reduced Percentage Open Cells – a new parameter for comparing the efficiency of cane-preparation devices

As for the Reduced Mill Extraction and Reduced Boiling House Extraction formulae, which are used for comparing the mill and boiling house efficiencies, respectively, there is a need for a similar reduced efficiency parameter to determine the degree of cane preparation. A new parameter is proposed for judging the efficiency of cane preparation, termed Reduced Percentage Open Cells (RPOC). The degree of cane preparation is currently assessed, primarily, with two methods, Pol Percentage Open Cells (PPOC) and Preparation Index (PI). An analysis concluded that the PI value is not a true indication of the percentage of cell rupture in the prepared cane, but is simply an arbitrary ratio of the concentrations of dissolved solids in the extracts from leaching and disintegration of prepared cane samples with equal cane to water ratios. Similarly, analysis of the method to determine PPOC shows that the assumptions and treatment considered with respect to fibre % cane need some minor corrections. To overcome the limitations of both PI and PPOC methods, a modified method for assessing the percentage of open cells, termed Percentage Open Cells (POC), is suggested and it forms the basis for the derivation of the formula for Reduced Percentage Open Cells (RPOC), at a standard fibre % cane value of 12.50. RPOC values are useful for meaningful comparisons and evaluation of cane preparation efficiencies. RPOC figures may be further extended to evaluate the power consumption for cane preparation, design of preparatory devices, mill tandem performance, etc. Key words Preparation efficiency, reduced preparation index, reduced percentage open cells, preparation index, pol percentage open cells, fibre% cane, percentage open cells