THE EFFECT OF WHOLE CROP PROCESSING ON SUGAR RECOVERY AND SUGAR QUALITY

THIS PAPER reports on experiments conducted at Condong and Broadwater factories in 2009 where three-day tests with different trash levels in the cane supply were conducted and large differences in trash levels were achieved. These experiments have shown quite conclusively that trash in the cane supply is detrimental to both sugar recovery and sugar quality. The results showed sugar recovery reduces by about 0.9 units for each 1 unit increase in cane fibre content caused by increased trash content. The sugar analysis results showed increased ash and colour and some evidence of decreased filtrability. The results indicated that the reduced sugar recovery was caused by greater pol losses in molasses, bagasse and mud, in decreasing order of importance. Increased pol loss in molasses occurs mainly through increased molasses production owing to the increased loading of soluble impurities entering with the cane supply containing higher trash levels. Higher C molasses purities also occurred and these are mainly attributed to a worsening of exhaustion in the high grade massecuites and a subsequent increase in C massecuite purity. The greater pol loss in bagasse appears to be caused mainly by the greater quantity of bagasse, and minimising that pol loss will require that cane preparation and added water rates are maintained at satisfactory levels. The results show increased quantities of mud solids with increased quantities of trash and this is largely responsible for the increased pol loss in mud.