PLANT EXPERIENCE WITH REPLACEMENT OF A THREE STEP DRUM FILTER PLANT BY A ONE STEP PAN FILTER AT AL-HYDRATE PRODUCT FILTRATION

Hahn, J., Bott, R. and Langeloh, T.

In the last decade BOKELA has introduced a new generation of rotary pan filters with new and innovative design. Plant experience with operating pan filters at several Al-refineries verify that the filtration and washing of Al-hydrate product with this new pan filter generation is performed with improved filter capacity, improved product quality and reduced operation and maintenance cost.

Now, the first pan filter equipped with FrameTrak - a new method of filter cloth attachment to rotary drum and pan filters – has started operation replacing a 3-step drum filter plant in an alumina refinery. Operation results show that product filtration is now performed with significantly improved results such as 50% reduced wash condensate consumption with simultaneously reduced Na2O-content (no more peaks) and with reduced filter cake moisture.

Operation results and design characteristics of this modern pan filter, which is the first pan filter world-wide that is equipped with FrameTrak, are presented and it is reported on first plant experience with this new method of filter cloth attachment that replaces the traditional caulking method or bolt down clamping methods.