Vacuum filters Nutsche

The pressure versions of the nutsche filter, which falls into this category, are either simple pressurized filter boxes or more sophisticated agitated nutsches, much the same in design as the enclosed agitated vacuum filters described eadier. These are extremely versatile, batch-operated filters, used in many industries, eg, agrochemistry, pharmaceuticals, or dyestuff production. 

This family of filters consist of a vertical pressure vessel with a horizontal filter plate at the bottom. The filtrate from this equipment flows out a nozzle on the bottom of the filter. These devises are usually used for slurries where large amounts of solids are being collected. Variations of this equipment include equipment with removable lower heads for easy cake removal, ability to pressure or vacuum filter, ability to wash the filter cake, an agitator to break-up and rewash the filter cake, and heating or cooling jackets for the whole vessel. The Nutsche filter is the industrial version of the well known laboratory scale Buchner Funnel with the exception that it is designed to operate under either on vacuum or pressure. 

Batch vacuum filters were developed from gravity filters and, in essence, Buchner funnels as used in laboratories and Nutsche type filters as used in industry are similar to gravity filters, except that they feature a vacuum pump or some other vacuum generating equipment to reduce the pressure under the filter medium, thereby increasing the driving force across the filter medium. 

The flushed silanol is sampled to determine the solid residue, which should be 15-24%, and the gelatinisation time at 200 2 °C (the standard value is 0.5-60 minutes). After that, silanol is sent with vacuum through nutsch filter 8 into tank 9, which is an enameled apparatus with an agitator and a water vapour jacket, to distil the solvents. Before the distillation the product of hydrolytic condensation is held at 20-25 °C to eliminate traces of moisture. The distillation is conducted at 45-50 °C and a residual pressure of 105-80 GPa until the solid residue is 40-55%. Then the jacket of the tank is filled with water and the varnish is cooled to 20-25 °C. During the distillation of the solvents, the product of hydrolytic condensation is further condensed to form a higher-molecular polymer. 

Partial hydrolytic condensation can be carried out in the same apparatus 1. It is filled with a necessary amount of water within 0.5-1 hours, when the temperature of the reaction medium is 80-85 °C. The temperature in the reactor is increased to 95-100 °C, the reactive mixture is held at agitation for 7-8 hours and cooled down to 20-25 °C. The cooled polybutoxy-phenylsiloxane mixed with butyl alcohol, which has been formed in the process of hydrolytic condensation, is sent with vacuum through nutsch filter 5 into distillation tank 6. In the tank polybutoxyphenylsiloxane is clarified at 50-60 °C, poured into batch box 7 and sent with vacuum into reactor 8. Re-etherification is carried out in stainless steel apparatus 8 with a water vapour jacket and an anchor agitator. After loading polybutoxyphenylsiloxane, the apparatus is filled with a necessary amount of dipheny-... 

DISCONTINUOUS VACUUM FILTERS. Pressure filters are usually discontinuous vacuum filters are usually continuous. A discontinuous vacuum filter, however, is sometimes a useful tool. A vacuum nutsch is little more than a large Buchner funnel, 1 to 3 m (3 to 10 ft) in diameter and forming a layer of solids 100 to 300 mm (4 to 12 in.) thick. Because of its simplicity, a nutsch can readily be made of corrosion-resistant material and is valuable where experimental batches of a variety of corrosive materials are to be filtered. Nutsches are uncommon in large-scale processes because of the labor involved in digging out the cake they are, however, useful as pressure filters in combination filter-dryers for certain kinds of batch operations. ... 

The plant required for the above operations is relatively simple digestion is carried out in a stainless-steel vessel, steam jacketed, fitted with a stirrer, reflux condenser, conical base and bottom outlet. Special provision is made for passing a slow stream of hydrogen into the vessel via a pipe at the base. Filtration is on a Nutsche vacuum filter, a suitable filter medium being paper between two layers of terylene cloth. An additional clarification stage is also used to remove fine suspended particles of iron oxide. A bed of firmly packed paper pulp is satisfactory for this purpose. 

Single leaf (Nutsche) vacuum filter (Sections 1.4.1.1 and 6.1.1)... 

The tipping (tilting) pan filter obviously, and the rotary table filter somewhat less obviously, are developments of the simple batch vacuum filter described in the previous chapter. The single lipping pan is a batch filter, just like the Nutsche, but other versions, including the table filter, are intended to allow more or less continuous operation. 

Nutsche Filter. The nutsche filter (Fig. 8) is simply an industrial-scale equivalent of the laboratory Buckner funnel. Nutsche filters consist of cylindrical or rectangular tanks divided into two compartments of roughly the same size by a horizontal medium supported by a filter plate. Vacuum is apphed to the lower compartment, into which the filtrate is collected. It is customary to use the term nutsche only for filters that have sufficient capacity to hold the filtrate from one complete charge. The cake is removed manually or sometimes by reslurrying. 

Nutsche Filters A nutsche is one of the simplest batch filters. It is a tank with a false bottom, perforated or porous, which may either support a filter medium or act as the filter medium. The shiny is fed into the filter vessel, and separation occurs by gravity flow, gas pressure, vacuum, or a combination of these forces. The term nutsche comes from the German term for sucking, and vacuum is the common operating mode. 

Batch vacuum leaf Batch nutsche Batch pressure filters Plate and frame Vertical leaf Horizontal plate Cartridge edge... 

This type is similar in operation to a vacuum Nutsche filter. It consists of shallow pans with perforated bases, which support the filter medium. By arranging a series of pans around the circumference of a rotating wheel, the operation of filtering, washing, drying and discharging can be made automatic. 

The next step.was the removal of ammonia from the crude soln , which was done by steam-stripping in an evaporator to an ammonia recovery system, where NH, was absorbed in w. The resultant NH,-free crude soln was filtered through a Nutsch type filter to remove the catalyst and other insol impurities. The filtrate referred to as clear liquor was stored in a 1000 gal tank from which it could be transferred by suction into either of two 280 gal jacketed evaporators. The evaporation was conducted under 24" vacuum with 50 lb steam press in the jacket. A total of 425 gal of "clear liquor was concentrated until a sample of its "mother liquor showed the strength of 35% NaOH. During this operation the bulk of NaN, being less sol in w than NaOH, pptd. Then the mixt was cooled to 80-90°F (27-32°) (to cause the pptn of addnl NaN,) and dropped to a wringer. The yield was ca 75% NaN, and the overall cycling time was 5 6 hrs... 

Fig. 1. Production diagram of methylphenyldichlorosilane by organomagnesium-synthesis 1,2- dehydration boxes 3,4,7,11- batch boxes 5 - agitator 6, 9, 14 - coolers 8 - reactor of phenylmagnesiumchloride synthesis 10 - reactor of methylphenyldichlorosilane synthesis 12 — nutsch filter 13 — vacuum distill-ingtank 15-18- collectors 19- container.

After the distillation of toluene begins the distillation of aniline. The distillation of aniline is conducted up to 160-165°C in the tank (under a residual pressure of 30 GPa) and collected in receptacle 15. From there aniline is sent in vacuum into batch box 8 and used for another process of amidation. The target product which remains in tank 12, methyl(phenylaminomethyl)diethoxysilane, is cooled down to 30-50 °C, filtered in nutsch filter 16 and collected in box 17. After 2-3 days of standing, methyl(phenylaminomethyl)diethoxysilane is sent from box 17 into depository 18. 

The second stage, the amidation of chloromethyltriethoxysilane with hexamethylenediamine solution in toluene is conducted at 90-120 °C for 3.5-5 hours. The l-aminohexamethylene-6-aminomethyltriethoxysilane (raw AHM-3) formed is filtered in the nutsch filter and purified from the cake of hydrogen chloride hexamethylenediamine. Then toluene is distilled from raw AHM-3. Toluene is distilled in vacuum (P 52+160 GPa) up to 145 °C (liquid). The distillation is considered complete when the density of the product ranges from 0.945 to -0.965 g/cm3 and no20 =1.440-1.446. The prepared product, l-aminohexamethylene-6-... 

Fig. 33. Diagram of triacetoxymethylsilane production with potassium acetate 1 -vacuum drafts 2-4 -batch boxers 5 - cooler 6 - reactor 7, 9, 10 - collecors 8 nutsch filter.

Apart from triacetoxymethylsilane, the acetylation also yields potassium chloride, which is separated from the target product in nutsch filter 8 at 0.07 MPa. The toluene solution of triacetoxymethylsilane, separated from potassium chloride, is collected into collector 9 and then sent to the vacuum distillation of toluene, which takes place in a conventional distillation tank (not shown in the diagram). 

Fig. 39. Production diagram of high-viscosity oligomethylsiloxanes 1-4, 6- batch boxes 5- agitator 7- hydrolyser 8, 13 - condensers 9- absorption column 10, 12 - collectors 11 - vacuum distillation tank 14 - receptacle 15 - settling box 16 -nutsch filter...

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