The effect of particle size on Dorr first and second carbonatation filtration

As beet factories continually seek to maximize throughput and minimize lime usage, considerable demand is placed on juice filtration. Difficulties with first carbonatation filtration can result in more sugar being lost with the carbonatation lime (‘LimeX’ co-product) as well as lost throughput opportunity. Difficulties with second carbonatation filtration can result in lost throughput opportunity as well as high levels of particulate matter in the juice going forward to evaporators. British Sugar’s work during the 2000/01 beet processing campaign has explored the relationship between precipitate particle size and juice filtration in both first and second carbonatation juices.

A Malvern Mastersizer laser was successfully used for particle size analysis. As might be expected, a strong negative correlation was established between particle size and juice filterability i.e. the smaller the particle size, the slower the juice filtration. Factors which are believed to influence particle size are discussed.

For future work, the authors hope to establish those parameters which can be influenced in order to optimize the particle size.