Florentine filter

As an alternative to the rotary filter drum, the filter may be stretched into a horizontal continuous belt, around two rotating drums, as shown in the diagram in Figure 12 of a Florentine filter from a Tirtiaux plant. Filtration takes place on the upper, horizontal surface of the belt, which has a vacuum chamber beneath it. In the diagram shown, the first portion of the filter belt, which in this case is perforated stainless steel, allows for any crystal fines to be recycled so they do not contaminate the olein fraction. 

Membrane filters are similar to the plate-and-frame filters that were once common in bleaching plants. A number of manufacturers offer these for fractionation, and each has its own particular preferences regarding the feed position and the materials used in manufacturing the plates. For example, Tirtiaux plants can be coupled with membrane filters as an alternative to the Florentine filter, as shown in Figure 13. 

Figure 31 Florentine filter, shrouded and air-conditioned for cryofractionation. 

In the production of edible oils from oil seeds and oil-rich fruits it is necessary to process the crude oil to separate pure oil (olein) from the crystalline solids (stearin), the amount of each depending on the temperature of the process. The growing importance of pahn oil processing meant that the traditional rotary vacuum filter was not sufficiently effective in this separation, and the Florentine filter was developed to enable higher processing rates in a continnons flow. This dry fractionation step is used in the treatment of a wide range of oils and fats, from 2°C (hardened soybean oil) up to 45°C (tallow). 

Fig. 48. Production diagram of tris ro-butoxyoligo[(propyleneoxy)(ethyleneoxy)-(dimethylsiloxy)] ethylsilane 7, 2, 9,11,12 - batch boxes 3, 10- reactors 4, 21 -coolers 5, 6, 8, 16, 17, 19, 22 - receptacles 7, 18 - pressure filters 13 - packed tower 14 - refluxer 75 - Florentine flask 20 - distillation tank 23 - container...

Fig. 65. Production diagram of polymethylsilsesquioxane varnish by the continuous technique 1, 2, 4, 5,8, 10 - batch boxes 3 - agitator 6 - hydrolyser 7, 12 -Florentine flasks 9 - heat exchanger 11 - neutraliser 13 - flusher-receptacle 14, 16, 18 - collectors, 15 - vacuum distillation tank 17 - cooler 19 - balancing tank 20 - druck filter...

Fig. 68. Production diagram of polyphenylsilsesquioxane from triacetoxyphenylsi-lane 1 - 4 - batch boxes 5 - reactor 6, 12 - coolers 7 - Florentine flask 8 - nutsch filter 9, 10, 13 - collectors 11 - distillation tank...

A popular variant of the rotating drum vacuum filter has been widely applied especially for the palm oil industry. The Florentine vacuum filter uses a horizontal stainless steel perforated belt with vacuum applied under the belt. This design includes a recycle from the first filter section, which is said to allow the first layer of stearine to act as a continuous precoat (25). 

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