Standard liquor filtration using a Putsch Sibomat filter

Standard liquor filtration is typically accomplished using diatomaceous earth (filter aid) as the filtering medium. The Putsch Sibomat filter offers an alternative that does not require the use of filter aid. Rogers Sugar Ltd (Taber) initiated a test starting in the spring of 2003 with the objective to test the effectiveness of the Sibomat in terms of filtrate quality and filter capacity and to identify whether elimination of filter aid could be achieved. Standard liquor filtration at Taber consumes on average 2 kilograms of filter aid per tonne of sugar produced, at a campaign cost approaching $100,000 Canadian. Elimination or major reduction in the filter aid consumption can produce an attractive economic payback. The Sibomat filter test unit supplied by Putsch was a full-scale assembly with only one filter basket. Fitted with a 55-micron screen element, it was installed in parallel with the factory's main filter station. Following testing during two juice campaigns and two beet campaigns, results to date indicate suitable beet campaign operation with significant filter aid savings, but unacceptable performance over both juice campaign periods. During the first juice campaign, filter aid contamination of the Sibomat feed contributed significantly to the poor results. Unfortunately, correction of this issue for the second juice campaign did not produce an acceptable improvement in filtrate quality. Very fine suspended matter in the stored thick juice could not be removed even after changing to a 33-micron screen element. After correcting a number of commissioning issues during the first beet campaign, the Sibomat handled up to 75% of the total juice flow (34 m 3 /hour average) producing suitable quality filtrate with acceptable cycle times (80 to 90 minutes). The consumption of filter aid was reduced by more than 50%. During the second beet campaign, intermittent performance issues were identified. This, plus higher average liquor flow, contributed to reduced filter aid savings. Although there is excellent potential for significant filter aid savings when using the Sibomat for beet campaign, current data suggests that total elimination of the diatomaceous earth filtration station cannot be recommended.