Abstract
In times of ongoing energy crisis and uncertainties, it is more important than ever before to reduce energy demand wherever possible, same is valid for the sugar industry. This triggered several European beet sugar factories to rethink dilution factors like for example in the remelt of c-massecuite centrifuge run-off, to save on water input as well as evaporation energy. A bottleneck lies within the filtration of these standard liquor streams, as the sugar content is a limiting factor for many available filter systems. Also sugar contents up to 80 brix and even higher are beyond their capability. This is not the case for the Lenzing OptiFil, which already before has proven to be a highly efficient equipment in 100+ sugar installations and was now challenged with the task of filtering standard liquor streams at 80 brix and finest filter ratings between 20 and 50 µm. Conventional automatic filters have not been able to backwash their filter material properly even at coarser filtration ratings (80 µm and coarser), leading to downtime for manual cleaning and requiring already limited manpower for the same. On the other hand, disposable filter bags have been used. However, due to the presence of sticky particulate in high concentrations, these filters required even more attention for exchange of the bags and therefore high operational expenses (OPEX) and manual labor. Not to mention the disposal of the same. On the other hand, the OptiFil – with its patented backwash mechanism – is capable of filtration down to 20 µm and operates fully automatic throughout a full campaign creating reject rates between 0.6 and 1.0 % of the respective inlet flow rate. Due to this fact and the extraordinary short ROI through reasonable energy savings, this filter system was implemented in six different factories throughout Europe in only one year, even more to come. This paper provides a comprehensive outline on the filtration systems tested for highly concentrated standard liquor and describes the implemented solution at several individual installations.
