KR20020066369A - Pressure filtration device and method employing a depressurizing chamber and material transport - Google Patents

Abstract

The present invention relates to an apparatus for separating solid material from a slurry constituting a pressure filtration device comprising a container and a filter media. The slurry 5 is provided to the filtering device 10, and is separated into a solid material and a liquid material. The filtering device 10 includes a solid outlet 12 for discharging the solid material to the material moving means 15. The material moving means 15 moves the solid material to the decompression chamber 20 having a pressure lower than that of the filtration device 10. The solid material is in contact with the decompression chamber 20, thereby exposing the lower pressure of the decompression chamber. The material moving means 15 maintains the pressure difference between the filtration device 10 and the decompression chamber 20. The reduced pressure solid material may then be transferred to another apparatus for drying or other processes.

Description

PRESSURE FILTRATION DEVICE AND METHOD EMPLOYING A DEPRESSURIZING CHAMBER AND MATERIAL TRANSPORT}

In chemical processes, the process of separating the solid material from the slurry is often necessary. For example, the slurry is produced by chemical reactors and accelerators. Generally, the solid material is separated from the slurry through a filter or centrifuge. Preferred filtration methods are gravity, vacuum and pressure filtration. For example, clarified terephthalic acid, terephthalic acid crystals are typically separated from the slurry via a rotary vacuum filter. The filtration device includes a cylindrical filter drum with a housing rotatably mounted therein. When the slurry is fed into the filter housing, a pressure difference is created inside the filter, which moves the liquid portion of the slurry through the filter media. The crystals adhere to a layer on the outer cylindrical surface of the drum.

After separating the solid material from the slurry, the solid material is removed from the filter media, usually before the next process or treatment, depending on the cake of the solid material. In some applications, injection of pressurized gas removes the solid material from the filter media and injects the solid material into the outlet. Processes using pressurized filters require that the solid material be discharged at lower pressures (such as atmospheric conditions) for subsequent processing. In the continuous process function, it is required that the pressure difference in the filtration device is not significantly different.

U. S. Patent 5,093, 001 relates to a pressure filtration device having a pair of valves at the output for material discharge. Such patents are incorporated in the present disclosure by reference herein. However, the structure is insufficient to solve the pressure control problem and to maintain a high level of material throughput through the filtration device. U.S. Patents 5,589,079 and 5,470,473 relate to a pair of valve devices and hoppers for batch processing solid materials in a pressure filtration device. Such patents are incorporated in the present disclosure by reference herein. Each valve device includes a dome type valve member. The solid material has a function of being discharged from the filtration apparatus to the first hopper. The valve device attached to the first hopper equalizes the pressure between the first and second hoppers while sealing the hopper. The pressure is halfway between the initial pressure and the lower late pressure. After the pressure is equalized between the hoppers, the solid material is transferred to the second hopper. The second hopper is depressurized to a lower late pressure, and then the solid material is discharged to a reservoir or conveyor. The apparatus and method are superior to conventional apparatus and methods, but the apparatus and method are limited to batch processing of solid materials. Multi-storage, batch processes can become a bottleneck, making high-speed, continuous processing of material yields impossible. In addition, the valve device and the pressure balancer require a normal sustaining function to keep the device operating efficiently. Accordingly, there is a need for a pressure filtration device for continuously processing solid materials. In particular, there is a need for a pressure filtration device that maintains the pressure difference between the filtration device and the subsequent device while continuously treating the slurry by depressurizing the solid material separated from the slurry at high speed.

The present invention relates to a filtering device and a method for separating a slurry into a solid phase and a liquid phase. More specifically, the present invention relates to a pressure filtration apparatus and a method for continuously separating solid materials from a slurry and decompressing solid materials at high speed.

1 shows a side view of a pressure reducing filtration device having a vessel wall cutout,

2 is a flow chart of an embodiment of a pressure filtration system.

An apparatus for continuously recovering solid material from a slurry, which is a vacuum filtering apparatus according to the present invention, includes a container provided with a filter medium for separating solid material from a slurry. The filtration device has a slurry input and optionally has a source of inert gas. The liquid outlet discharges the liquid material from the filtering device. Gas may also be vented through the liquid outlet, depending on the design of the filtration device. The liquid outlet discharges the solid material from the filtering device. The filtration device may optionally include a washing device for dispensing the washing fluid or solution onto a cake of material adhered to the filter media. The wash fluid removes impurities and / or other liquids from the cake.

The material moving means continuously moves the solid material from the solid outlet of the filtering device to the pressure reducing chamber. The decompression chamber has a lower pressure than the filtration device to facilitate the subsequent processing of the solid phase material. By moving the solid material into the decompression chamber, the solid material is decompressed directly and at high speed to the lower pressure of the chamber.

In addition, the high-speed decompression has the advantage of causing "flashing" of the solid material and removes residual liquid, gas and volatile components. The decompression chamber further comprises one or more outlets for spinning vapor, gas and / or volatile elements in the chamber. The decompression chamber contains an inert gas to stabilize reactive or other unstable solid materials. Any suitable delivery means can remove the solids from the chamber through the drying process.

The material moving means generally includes an inlet for receiving solid material from the solid outlet of the filtering device. The solid material is discharged to the material moving means inlet under pressure. It is a feature of the present invention that the material transport means maintains a pressure difference between the filtering device and the pressure reducing vessel. The solid material moves to the outlet and is discharged into the decompression chamber. The material is decompressed at high speed by exposure to low pressure in the decompression chamber.

According to another aspect of the present invention, in at least one filter system, a pressure reducing device and a means for moving the material are provided. The system further includes one or more chemical reactors or promoters to provide a source of slurry to the filtration device. The conveyor may be a spiral conveyor or other form of delivery means.

According to another aspect of the invention, according to another aspect, the step of separating the solid material from the slurry comprises the steps of (a) providing a filtration device comprising a vessel and a filter media maintained at a first pressure, (b) Injecting a slurry into the vessel, (c) separating the slurry into a solid material and a liquid material, and (d) continuously moving the solid material to the decompression chamber while maintaining a pressure difference between the filtration device and the chamber. And (e) depressurizing the solid phase material at high speed by exposing it to a decompression chamber. The solid phase material is substantially maintained at a first pressure state until it is exposed to the decompression chamber, and this state is maintained even if a small amount of controlled pressure leaks while the solid phase material is moved. Additional steps further include (f) providing the slurry from the chemical reactor and (g) delivering the reduced pressure solids material to the dryer.

Referring to FIG. 1, an apparatus for separating solid material from slurry 5 is schematically illustrated. The apparatus comprises a filtration device 10 with a solid outlet 12 for discharging solid material separated from the slurry by the filtration device 10. The liquid outlet 11 is for discharging the liquid material or, optionally, the gaseous material. The material movement means 15 is connected to the filtration device 10 at the solid outlet 12. Optionally, the filtration device 10 and the material transporter 15 may be interconnected by an adapter 14. The adapter 14 is particularly practical for improving the filtering device. The material moving means 15 is connected with the decompression chamber 20 on its downstream side. Chamber 20 preferably includes one or more outlets 25 that exhaust vapor, gas, and / or volatile elements (generally "vapor") from chamber 20. The chamber 20 may be further connected with a conveyor and / or dryer (not shown) for further processing of the solid material.

Filtration device 10 includes a vessel 13 containing slurry 5 and filter media 8. The filtration device 10 may be any device for separating the slurry 5 into solid and liquid materials. Since the filtration device 10 is pressurized, a cylindrical or spherical shape is preferred, although other forms are possible. For example, as described in US Pat. Nos. 5,589,079, 5,470,473, and 2,352,303 for rotating drum filtration devices, the filtration device 10 may be pressurized, which patent is incorporated by reference in the present disclosure. Slurry 5 is provided to filtration device 10 from a suitable source such as, for example, a chemical reactor or accelerator (not shown). The slurry 5 is fed into the filtration device 10 through the inlet 3. The inlet 3 can be configured and positioned to inject the slurry 5 into the filter device 10 according to the design and function of the particular filter device, as is known. Other pressure filtration devices, such as pressure disk filter devices, are also suitable for use in the present invention.

The filtration device 10 is pressurized to easily separate the slurry 5 through the filter media 8 into a solid material and a liquid material. The filtration device 10 is pressurized according to the design of the device. For example, referring to FIG. 1, the filtration device 10 is pressurized from a source 30 of pressurized gas, such as an inert gas. Another method of pressurizing the filtration device 10 is to inject the pressurized slurry into the filtration device 10.

The filter media 8 separates the slurry into liquid and solid materials. The filter media 8 is selected according to the separated slurry. For example, the filter media 8 may be a layer of cloth fibers or stainless steel provided to surround the outer surface of the steel drum. In some applications, it is desirable that the filter media be able to withstand elevated pressure as well as elevated pressure. The "liquid material" described above refers to the liquid separated from the slurry, even if the liquid contains some floating solid material. The " solid material " refers to a material separated from the slurry by the filter media 8, for example, a cake adhered to the filter media. The solid phase material also includes actual liquids such as liquids and / or wash fluids that are not separated from the solid material. The temperature of the solid material can be higher than the atmospheric boiling point of the liquid contained in the solid material. When the hot material is decompressed or flashed at high speed, the liquid vaporizes at high speed by lowering the pressure, or the pressure and temperature. For example, when a pressurized solid material containing water and having a temperature higher than 212 ° F. is rapidly depressurized to atmospheric pressure, the water of the solid material forms vapor and vaporizes at high speed. Other pressurized, heated, liquid-containing solid materials can be processed using the device.

The filtration device 10 optionally includes a washing device 7 for dispensing the washing fluid or solution onto the cake adhered on the filter media 8 during the filtration process. The washing fluid may be injected under pressure to the filter through the cake or solid material. The wash fluid removes residual moisture in the cake, impurities in the cake and / or removes liquid from the cake with the wash fluid. The wash fluid may be, for example, water used to remove acetic acid from the terephthalic acid crystals before the material exits the solid outlet 12. An example of a preferred washing apparatus is a header spanning vessel 13 which dispenses the washing liquid into the cake. Other washing fluids and devices are possible.

The solid material is known to be discharged from the filter media by a suitable mechanism. For example, the injection of pressurized gas inside the rotating cylindrical filter may push the adhered cake out of the outer surface of the filter media and the solid outlet 12. Similarly, the cake may be mechanically removed from the filter media 8 via a scraper or similar device (not shown). Other devices for discharging solid material from the filtering device are usable within the scope of the present invention.

The material moving means 15 includes an inlet 16 for receiving solid material from the solid outlet 12 of the filtering device 10. Since the inlet 16 communicates with the filtration device 10, the inlet is pressurized. The material moving means 15 moves the solid material to the outlet 18. The movement of the solid phase material is preferably continuous and the solid phase material moves from the inlet to the outlet without the phenomenon of stepwise pressure reduction or pressure equalization between the filtration device 10 and the pressure reduction chamber 20. The material moving means 15 allows the solid material to be continuously moved through it while maintaining the pressure difference between the filtration device 10 and the pressure reduction chamber 20. Referring to FIG. 1, there is a rotating valve as an example of the material moving means 15. The rotary valve has a plurality of rotatably mounted vanes 19. The solid material sticks between the vanes and is thus moved to the outlet 18. The vanes 19 are preferably in sealing contact with the inner surface 17 of the rotary valve so as to maintain a pressure differential between the filtration device 10 and the pressure reducing chamber 20. The vanes 19 also receive a small amount of controlled leakage of the pressure through the vanes, so that the cake on the filter media 8 does not change and the pressure difference between the filtration device 10 and the decompression chamber 20 is maintained. Other material transfer means 15 are possible.

The material moving means 15 is operated by suitable means. For example, referring to FIG. 1, the material moving means 15 is operated by the drive 40, the bearing device and the drive shaft 41. An example of drive 40 may be any device that provides mechanical force to material moving means 15, such as an electric motor, a combustion engine.

The decompression chamber 20 includes a solid inlet 22 for receiving solid material transferred from the filtration device 10. The side wall 24 is in a low pressure state of the decompression chamber 20 when solid material is introduced or exposed. The low pressure of the chamber 20 is preferably approximately atmospheric pressure, although the pressure used in the chamber 20 is higher or lower than atmospheric pressure. The decompression chamber 20 has at least one outlet 25 through which the vapor formed by exposing the solid material to the low pressure of the chamber. The outlet 25 may be exposed to the atmosphere or connected to a reservoir and / or a regeneration system (not shown). These systems facilitate the regeneration and purification of the gas or vapor liquid exiting the reduced pressure tank 20.

Decompression chamber 20 optionally contains a gas, such as an inert gas, to limit the reactivity of the solid material and / or to block the process to prevent ignition. For example, referring to FIG. 1, the reduced pressure chamber 20 is connected to a source 30 of inert gas such as nitrogen, argon, helium or carbon dioxide. As is known, the gas is selected according to the reactivity of the solid material.

In another aspect, a slurry filtration system is provided. One or more filtration devices 10 are connected with one or more material moving means 15 and one or more pressure reducing chambers 20. 2, an example of such a system is shown. Source 1 provides slurry 5 to filtration apparatus 10. Source 1 includes a chemical reactor, accelerator, extraction device, waste processor, or other suitable device for supplying a slurry containing solid and liquid materials. Each filtration device 10 is connected to a material moving means 15. The material moving means 15 moves the solid material to the common pressure reducing chamber 20, and it is also possible to use a plurality of pressure reducing chambers 20. The solid material is transferred from the decompression chamber 20 to a dryer or other solid material processing device 60 via a conveyor 50 (eg, a spiral conveyor or other machine for moving the solid material). The conveyor 50 and the device 60 are preferably subjected to continuous movement and continuous process processing. The operation ratio of the conveyor 50 is adjusted according to the output rate of the solid material and the slurry supply rate during operation. Other configurations of the system are possible.

In yet another aspect, a method of separating a solid material from a slurry is provided. The method includes providing a filtration device 10 with a container 13. The vessel 13 is maintained at a first pressure state. The slurry 5 is injected into the vessel 13 through the inlet 3. The slurry 5 is provided from a suitable source 1 such as a chemical reactor, accelerator, extraction device, processor, or other suitable device for supplying a slurry containing solid and liquid materials. The slurry 5 is separated into a solid material and a liquid material using the filter media 8. Optionally, the solid material may be washed. The solid material is then moved to the decompression chamber to maintain the pressure difference between the filtering device and the decompression chamber. The solid material is preferably continuously moved or continuously transferred from the filtering device 10 to the pressure reducing chamber 20, for continuous filtration and processing of the solid material. The solid material is decompressed directly and at high speed by being exposed to a decompression chamber, without a pressure balancer requiring another method. Preferably, the solid material is substantially maintained in the first pressure state until it is exposed to the decompression chamber. In addition, the solid phase material is transferred from the filtration apparatus to the chamber with partial pressure reduction. The decompressed solid material is transferred from the decompression chamber by a suitable delivery device. The next step is to dry the solid material and / or to provide the solid material to other devices for further processing or processing.

Preferred embodiments of the present invention are disclosed for purposes of illustration, and those skilled in the art will be able to make various modifications, changes, additions, and the like within the spirit and scope of the present invention. something to do. Accordingly, the accompanying drawings and the above description are intended to explain the present invention in detail and are not intended to limit the scope of the present invention.

Claims (29)

A container maintained at a first pressure state, a filter media in the container separating the slurry into a liquid material and a solid material, a liquid outlet for discharging the liquid material, and a solid outlet for discharging the solid material from a filtration device. A pressure filtration device; A reduced pressure chamber having a solid inlet, the solid pressure material being maintained at a second pressure lower than the first pressure and containing the solid material from the filtering device and exposed to the second low pressure; And A material transfer means is provided between the solid outlet of the filtration device and the solid inlet of the chamber to maintain a pressure difference between the filtration device and the chamber and to continuously move solid material from the solid outlet of the filtration device to the chamber, Continuous pressure filtering device for the slurry, characterized in that the solid material is decompressed to a second pressure lower than the first pressure. The method of claim 1, Continuous pressure filtering device for the slurry, characterized in that it further comprises a source of slurry connected to the filtration device. The method of claim 2, Continuous pressure filtering device for the slurry, characterized in that the source of the slurry is a chemical reactor. The method of claim 1, Continuous pressure filtering device for the slurry, characterized in that it further comprises a source of inert gas connected to the filtration device. The method of claim 1, And a dryer connected to the chamber to receive solid material from the chamber. The method of claim 1, Continuous pressure filtering device for the slurry, characterized in that it further comprises a conveyor for transferring the solid material from the chamber to the dryer. The method of claim 1, The material conveying means is a rotary valve comprising a housing having an outlet and an inlet and a rotor having a plurality of vanes, The housing inlet communicates with the outlet of the filtration device, while the housing outlet communicates with the decompression chamber inlet, at least a portion of the vane is exposed to the housing inlet, and at least a portion of the vane is exposed to the housing outlet, the vane Part of the continuous pressure filtering device for the slurry, characterized in that the sealing contact with the housing. The method of claim 1, Continuous pressure filtering device for the slurry, characterized in that the filter is a cylindrical filter rotatably mounted. The method of claim 1, And the solid phase material is crystallized at a temperature higher than the boiling point of the liquid at a second pressure. A container maintained at a first pressure, a filter media in the container separating the slurry into a solid material containing liquid material and a liquid, a liquid outlet for discharging the liquid material, and a solid outlet for discharging the solid material from the filtration apparatus. At least one pressure filtration device; A source of inert gas; Receive the inert gas and receive the inert gas in a second pressure state lower than the first pressure, and have an inlet for receiving solid material in the at least one filtering device, and directly to the second pressure which is lower pressure. At least one decompression chamber containing an exposed solid material and having an outlet for discharging steam formed by exposing the solid material to low pressure; At least one solid outlet of the filtration device to maintain a pressure difference between the at least one filtration device and the at least one chamber and to move solid material from the solid outlet of the at least one filtration device to the at least one chamber. And at least one material conveying means located between the solid inlets of the decompression chamber of By causing the solid material to have a temperature higher than the boiling point of the liquid contained in the solid material in the second pressure state; And pressure-reducing the liquid in the solid material as the solid material is decompressed as it is exposed to a second pressure, which is a low pressure. . The method of claim 11, And further comprising a source of slurry associated with said at least one filtration device. The method of claim 12. Pressurized filtration system for a slurry, characterized in that the source is a chemical reactor. The method of claim 11, And a conveyor for delivering solid material from the chamber. The method of claim 11, And at least one dryer connected to the chamber to receive the solid material. The method of claim 11, The material conveying means is a rotary valve comprising a housing having an outlet and an inlet and a rotor having a plurality of vanes, the housing inlet communicating with a filter outlet and simultaneously with the housing outlet communicating with a decompression chamber inlet. At least a portion of the vane is exposed to the housing inlet, at least a portion of the vane is exposed to the housing outlet, and a portion of the vane is in sealing contact with the housing. The method of claim 11, And at least one filtration device is a cylindrical filter rotatably mounted. The method of claim 11, Pressurized filtration system of the slurry, characterized in that the solid material is a crystal. The method of claim 11, And the second pressure is atmospheric pressure. The method of claim 11, And an adapter for connecting said filtration device to the material conveying means. Providing a filtration device comprising a container maintained at a first pressure and a filter media; Introducing a slurry into the vessel; Separating the slurry into a liquid material and a solid material; Maintaining the pressure difference between the filtration device and the chamber while continuously moving the solid material from the vessel to the pressure reducing chamber; And depressurizing the solid material in the chamber to a second pressure state lower than the first pressure. The method of claim 21, And supplying the source of the inert gas to the filtration device. The method of claim 22, And pressurizing the source of the inert gas to the chamber. The method of claim 21, Pressure filtration method of the slurry, characterized in that further comprising the step of discharging the gas formed during the decompression of the solid material. The method of claim 21, The pressure filtration method of the slurry, characterized in that it further comprises the step of transferring the reduced pressure solid material. The method of claim 24, The pressure filtration method of the slurry, characterized in that it further comprises the step of drying the reduced pressure solid material. The method of claim 21, And pressurizing the solid material to the at least one pressure reducing chamber. The method of claim 21, And the second pressure is substantially atmospheric pressure. The method of claim 21, And further comprising providing the slurry from a chemical reactor.