Filter dryer

Fig. 3. Typical nitric acid oxidation process. A, reactor B, optional cleanup reactor C, bleacher D, NO absorber E, concentrating stUl F, crude crystallizer G, centrifuge or filter H, refined crystallizer I, centrifuge or filter , dryer K, purge evaporator L, purge crystallizer M, centrifuge or filter N,...

Agitated/Monoplate Nutsche Filter/Dryer Horizontal Plate Filter/Dryer Continuous Equipment Rotary Drum Filter Centrifugal Filter Horizontal Belt Filter... 

The pressurized air goes to an air receiver for storage and then is processed for use by passing through filters, dryers and, in some cases, lubricators. This pressurized air is normally classified as instrument air when it is used in control systems. This air must be moisture and oil free to prevent the control devices from clogging up. 

Balance over reactor-filter-dryer sub-system gives flows to recovery column. 

When taking gas samples, the goal is to obtain representative samples with minimum time lag, using short, small-volume sampling lines. Whenever possible, it is preferred to draw dry and clean samples to minimize the need for filters, dryers, knockout traps, or steam tracing. 

Wet Dilevalol-DBTA Salt Slurry to Titus Filter Dryer... 

Balance over reactor-filter-dryer subsystem gives flows to recovery column, water, 44,892 + 10,101 — 532 = 54,461 kg monomer, unreacted monomer = 1122 kg... 

Vertical Agitated Dryers This classification includes vertical pan dryers, filter dryers, and spherical and conical dryers. 

Filter dryer The basic Nutsche filter dryer is like a vertical pan dryer, but with the bottom heated plate replaced by a filter plate. Hence, a slurry can be fed in and filtered, and the wet cake dried in situ. These units are especially popular in the pharmaceutical industry, as containment is good and a difficult wet solids transfer operation is eliminated by carrying out both filtration and drying in the same vessel. Drying times tend to be longer than for vertical pan dryers as the bottom plate is no longer heatra. Some types (e.g., Mitchell Thermovac,... 

Also, the mechanical power input of the agitator can be a significant additional heat source, and microwave assistance has also been used in filter dryers and conical dryers to shorten drying times (and is feasible in other es). 

The paddle with heated agitator has the shortest drying time, and the filter dryer the longest (because the bottom plate is unheated). Other types are fairly comparable. The spherical dryer would usually have a higher heat-transfer coefficient and shorter drying time than shown. 

Filter Dryers Basically this is a Nutsche filter (Sec. 18, Liquid-Solid Operations and Equipment ) followed by a batch dryer, usually of vertical pan type (see Batch Agitated and Rotating Dryers section). They are popular in the pharmaceutical and specialty chemicals industries as two unit operations are performed in the same piece of equipment without intermediate solids transfer, and containment is good. 

Slurries of Tree-filtering solids that are difficult to suspend are sometimes filtered on a top-feed drum filter or filter-dryer. An example application is in the production of table salt. An alternative for slurries of extremely coarse, dense solids is the internal drum filter. In the chemical-process industry both top-feed and internal drums (which are described briefly by Emmett in Schweitzer, op. cit., p. 4-41) have largely been displaced by the horizontal vacuum filter (q.v.). 

The vessel can also be jacketed for heating and/or cooling and the agitator blade heated. This design can now be a reactor in combination with a filter-dryer or alone as a filter-dryer (Fig. 10) (see also Chapter 17). This is particularly advantageous for dedicated production of toxic materials requiring an enclosed system. Operator exposure and product handling are minimized. 

Figure 10. Agitated nutsche type filter/dryer. (Courtesy of COGEMSpA).

The filtration unit can be a centrifuge or closed filter that is either a pressure or vacuum unit. Some processes may require solution washing of the crystalline product. Facility design should therefore be optimized for flexibility. Recent pressure/vacuum filtration units can perform several functions such as collection washing with appropriate solvents, solution washing, and drying of a crystalline product. These filter/dryer units offer the advantage of a closed system that protects product from people and vice... 

---