This invention is generally directed to an apparatus and methods of its use for separating particulates from liquids by filtration and further removing liquids from the particulates by drying. The present invention is greatly efficient in filtering and drying to yield a high quality product by employing a single container for both filtering and drying operations.
As known, particularly in producing chemical and pharmaceutical compositions, use is made of large filtration chambers and fluid-bed dryers. The filtration chambers generally consist of vessels, usually cylindrical, comprising a bottom part, a filter plate assembly, and a top part having diameters between 300 and 5,000 mm. The filtration chambers are used to remove liquids from particulate materials and solids.
Furthermore, the solids can be transferred to a fluid-bed dryer that uses a gas stream to remove moisture from the solids. Significantly, during the transfer of the solids from the filtration chamber to the fluid-bed dryer, the solids can be contaminated, spilled, lost, and/or degraded.
The present invention provides a method and apparatus by means which a particulate material is filtered and dried in a single product container. Performing both filtering and drying operations in a single product container reduces the risk of contaminating, degrading, or losing the particulate material.
The apparatus of the present invention filters and dries a particulate material having a liquid (e.g. solvent) content and comprises a single product container holding the material, that fits and adapts to a pressure filter system and a fluid-bed dryer system. Examples of typical solvents include the following: water, isopropyl alcohol, acetone, methyl alcohol, ethylene dichloride, methyl chloride, toluene, xylene, benzene, methyl ethyl ketone and hexane. Particle shapes of the particulate material have sphericity shape factors of 0.3 to 1.0 (1.0 being a sphere). The particulate sizes range from 1 μm to 20,000 μm, and more commonly from 2 μm to 10,000 μm.
Regarding “shape factors”, it is understood that many particles in packed beds are often irregular in shape. The equivalent diameter of a particle is defined as the diameter of a sphere having the same volume as this particle. Sphericity shape factor of a particle is the ratio of the surface area of this sphere having the same volume as the particle to the actual surface area of the particle.
The product container includes a vessel, usually cylindrical, having a detachable bottom plate forming a support for a filtering assembly. The filter assembly 13 comprises a filter sheet and a filter netting bed, both anchored to the bottom plate. The bottom plate can be removed.
The product container also includes a detachable upper plate forming a support for a gas distribution plate. The gas distribution plate comprises a perforated, sintered, or grid plate with or without a retention screen. The gas distribution plate can be installed before or after the filtering process.
After filtering the particulate material, the gas distribution plate is installed and the product container is inverted. The gas distribution plate supports the filtered material in the inverted position. The filter plate assembly is then removed from the product container.
The product container is installed into a fluid-bed dryer system. The fluid-bed dryer system consists of a lower plenum, an upper plenum, a dust collector, and a gas handling system. The gas handling system comprises at least one of a heater, a pressure blower, and a condenser.
The product container is installed between the lower and upper plenums. The gas (for example, air, argon, nitrogen, and carbon dioxide) stream is introduced into lower plenum. The gas stream flows through the gas distribution plate and the particulate material. The solvent in the particulate material is removed by the gas stream.
A filtering device in the upper plenum, above the product container, removes particulates in the gas stream and may be recycled. The solvent can be condensed from the gas stream and retrieved. The gas stream can be recycled to the dryer or vented to the atmosphere.
After the particulate material is adequately dried, the product is removed from the product container for packaging or additional processing.
The present invention provides a method and apparatus by means which a particulate material is filtered and dried in a single product container.
The product container 10 is usually mounted on a trolley 15 that allows the container to be moved to and from the processing areas (
The liquid/solids are introduced into the product container 10 with the detachable filter assembly 13 attached, which are components of the nutsche type filter assembly shown in
After the material is fed into the product container 10, the inlet head 12 to the nutsche filter assembly is attached,
After some of the liquid is removed from the material, the filter is depressurized. The solvent content of the particulate material after filtering is 1%-50%. The inlet head 12 is removed from the product container. The detachable gas distribution plate 11 is installed above the material in the product container 10 shown in
The nutsche type filter assembly is inverted so that the gas distribution plate 21 is on the bottom of the product container 20 shown in
The product container 30 with the gas distribution plate 31 is transported to the fluid-bed assembly. A trolley 35 shown in
A detachable cover 36 shown in
The product container 40 is installed between the upper plenum 43 and lower plenum 42 of the fluid-bed assembly shown in
The gas stream flows out of the fluid-bed assembly through the exhaust nozzle 47 shown in
An additional structural embodiment is shown in
Another structural embodiment is a fluid-bed assembly with an upper plenum 63 having the same diameter as the product container 60 shown in
Using the inlet head 82 shown in
Another structural embodiment is shown in
The invention is further illustrated, but not limited, by the following Examples:
The filter/dryer apparatus of the present invention was operated and tested on several types of materials. The filter/dryer removes the liquid from a mixture of a liquid and bulk solid, where as the solid is insoluble or soluble in the liquid.
The general procedure entailed the following:
First, 300 ml of the bulk solid was measured into a 1000 ml beaker. Second, the liquid was added to the beaker until the material was completely submerged in the liquid. That is, the liquid level and bulk solid level were equal in the beaker. Third, the volume of liquid required to submerge the bulk solid was recorded.
Once the initial solid/liquid mixture was prepared, the mixture was poured in a 4″ (Examples 1-4) or 16″ (Examples 5 and 6) diameter product container 10, which is a component of the nutsche filter assembly shown in
After 15 minutes of filtering the liquid in the nutsche filter, the filter assembly was depressurized. The amount of liquid that flowed out of the discharge head was recorded. The inlet head 12 was removed and the detachable gas distribution plate 11, shown in
The product container 30 with the gas distribution plate 31 was transported to the fluid-bed assembly. A trolley 35 shown in
A detachable cover 36 shown in
In Examples 1-4, the product container 40 was installed between the upper plenum 43 and lower plenum 42 of the fluid-bed assembly shown in
In Examples 5 and 6, the product container and gas distribution plate were transported to a fluid-bed dryer assembly shown in
A mixture of methyl alcohol, 83%, and magnesium oxide, 17%, where the particle range of the magnesium oxide was 5-50 μm, was fed into a 4″ diameter product container, which was a component of the filter assembly shown in
The inlet head was depressurized and removed from the product container. The detachable gas distribution plate was installed on the product container. The 4″ diameter product container was inverted so the gas distribution plate was on the bottom of the product container. The discharge head and detachable filter assembly were removed from the product container.
The product container and gas distribution plate were transported to a fluid-bed dryer assembly shown in
The results of Example 1 show that a non-aqueous solvent, methyl alcohol, can be removed from a bulk solid, magnesium oxide, with a small particles size distribution, 5-50 μm. The physical properties of the liquid/solid mixture was a stiff dry cake after the filtration process, a 31% moisture content. The fluid-bed dryer reduced the moisture content of the cake from 31% to 1.4%, which was a free flowing powder, 5-50 μm.
The fluid-bed dryer apparatus used in Example 1 is shown in
A mixture of acetone, 50%, and titanium, 50%, where the particle range of the titanium was 250-420 μm, was fed into a 4″ diameter product container, which was a component of the filter assembly shown in
The inlet head was depressurized and removed from the product container. The detachable gas distribution plate was installed on the product container. The 4″ diameter product container was inverted so the gas distribution plate was on the bottom of the product container. The discharge head and detachable filter assembly were removed from the product container.
The product container and gas distribution plate were transported to a fluid-bed dryer assembly shown in
Example 2 shows that the majority of liquid, 48%, can be removed during the filtration step when the solid, titanium, does not absorb the liquid, acetone. After the filtration step, the material was a free flowing mixture as opposed to the dry cake in Example 1.
A mixture of water, 50%, and polyethylene (plastic) beads, 50%, where the particle range of the polyethylene beads was 3000-6000 μm, was fed into a 4″ diameter product container, which was a component of the filter assembly shown in
The inlet head was depressurized and removed from the product container. The detachable gas distribution plate was installed on the product container. The 4″ diameter product container was inverted so the gas distribution plate was on the bottom of the product container. The discharge head and detachable filter assembly were removed from the product container.
The product container and gas distribution plate were transported to a fluid-bed dryer assembly shown in
Similar to Example 2, the filtration step in Example 3 removed the majority of the liquid water, 47% of the aqueous solvent (liquid water). However, the particle size of the plastic beads (3000-6000 μm) was much larger than the magnesium oxide (5-50 μm) or the titanium (250-420 μm).
The plastic beads, due to the size and shape of the beads, fluidized with slugging characteristics shown in
A mixture of isopropyl alcohol, 75%, and polyethylene glycol, 25%, where the particle range of the polyethylene glycol was 125-250 μm, was fed into a product container with a 4″ diameter at the gas distribution assembly and a 11″ diameter at the filter assembly, which was a component of the filter assembly shown in
Nitrogen was fed into the inlet head until the pressure above the mixture was 8 psig for 15 minutes. The liquid, isopropyl alcohol, flowed through the filter assembly and into the discharge head. The mixture in the product container after the filtering process had an isopropyl alcohol content of 30%.
The inlet head was depressurized and removed from the product container. The detachable gas distribution plate was installed on the product container. The 4″ diameter product container was inverted so the gas distribution plate was on the bottom of the product container. The discharge head and detachable filter assembly were removed from the product container.
The product container and gas distribution plate were transported to a fluid-bed dryer assembly shown in
Example 4 shows a nitrogen gas stream used during the fluid-bed drying step. Nitrogen and other inert gases are commonly used to dry non aqueous solvents to lower the oxygen concentration in the apparatus, which reduces the risk of an explosion.
During the fluid-bed drying step, the fluidization characteristics went from bubbling to smooth, shown in
A different product container assembly, shown in
A mixture of isopropyl alcohol, 85%, and polyethylene glycol, 15%, where the particle range of the polyethylene glycol was 50-300 μm, was fed into a product container with a 16″ diameter at the gas distribution assembly and a 16″ diameter at the filter assembly, which was a component of the filter assembly shown in
Argon was fed into the inlet head until the pressure above the mixture was 60 psig for 60 minutes. The liquid, isopropyl alcohol, flowed through the filter assembly and into the discharge head. The mixture in the product container, a wet cake, after the filtering process had an isopropyl alcohol content of 45%.
The inlet head was depressurized and removed from the product container. The detachable gas distribution plate was installed on the product container. The 16″ diameter product container was inverted so the gas distribution plate was on the bottom of the product container. The discharge head and detachable filter assembly were removed from the product container.
The product container and gas distribution plate were transported to a fluid-bed dryer assembly shown in
Example 5 shows a larger product container, 16″ diameter, than previous examples, 4″ diameter. A different fluid-bed assembly, shown in
The argon gas stream in Example 5 was recirculated. The gas stream from the fluid-bed dryer was passed through a condenser, which removed the majority of the solvent in the argon gas stream. The argon gas stream was heated by a heat exchanger before being recirculated to the fluid-bed dryer apparatus. Since a small amount of solvent was recirculated to the inlet of the fluid-bed dryer, the recycling fluid-bed drying step took more time than the once through drying step described in Example 4.
A mixture of isopropyl alcohol, 75%, and polyethylene glycol, 25%, where the particle range of the polyethylene glycol was 100-500 μm, was fed into a product container with a 16″ diameter at the gas distribution assembly and a 16″ diameter at the filter assembly, which was a component of the filter assembly shown in
Argon was fed into the inlet head until the pressure above the mixture was 25 psig for 60 minutes. The liquid, isopropyl alcohol, flowed through the filter assembly and into the discharge head. The mixture in the product container, a dry cake, after the filtering process had an isopropyl alcohol content of 35%.
The inlet head was depressurized and removed from the product container. The detachable gas distribution plate was installed on the product container. The 16″ diameter product container was inverted so the gas distribution plate was on the bottom of the product container. The discharge head and detachable filter assembly were removed from the product container.
The product container and gas distribution plate were transported to a fluid-bed dryer assembly shown in
The average particle size of the polyethylene glycol described in Example 6 was larger than the average particle size described in Example 5. Therefore, the argon gas stream flow rate was higher in Example 6, 140-300 ft/min, than in Example 5, 100-240 ft/min, during the fluid-bed drying step. The higher gas flow rates were required because larger particles, with the same particle density and shape, require higher gas velocities for fluidization.
The filter/dryer procedure was performed for several mixtures of bulk solids and liquids. The bulk solids ranged in size from 5 μm to 6 mm in diameter. The liquids were aqueous and non aqueous. The results of the tests are shown in Table 1.
1) The filter/dryer assembly can remove liquids from bulk solids with a wide range of particle size, 5 μm to 6 mm.
2) The filter/dryer assembly also has the ability to remove aqueous and non-aqueous liquids from bulk solids.
3) The initial moisture of the liquid/bulk solids feed to the filter/dryer can be as high as 83% and yet still achieve good moisture removal.
This is a continuation application of U.S. application Ser. No. 10/439,379 filed May 16, 2003 now abandoned.
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Child | 11898651 | US |