Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/16—Articles comprising two or more components, e.g. co-extruded layers
  • B29C48/18—Articles comprising two or more components, e.g. co-extruded layers the components being layers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
  • B01D53/34—Chemical or biological purification of waste gases
  • B01D53/38—Removing components of undefined structure
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
  • B29C48/04—Particle-shaped
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
  • B29C48/06—Rod-shaped
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/16—Articles comprising two or more components, e.g. co-extruded layers
  • B29C48/18—Articles comprising two or more components, e.g. co-extruded layers the components being layers
  • B29C48/21—Articles comprising two or more components, e.g. co-extruded layers the components being layers the layers being joined at their surfaces
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/25—Component parts, details or accessories; Auxiliary operations
  • B29C48/30—Extrusion nozzles or dies
  • B29C48/304—Extrusion nozzles or dies specially adapted for bringing together components, e.g. melts within the die
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/25—Component parts, details or accessories; Auxiliary operations
  • B29C48/36—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die
  • B29C48/49—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die using two or more extruders to feed one die or nozzle
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/25—Component parts, details or accessories; Auxiliary operations
  • B29C48/36—Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die
  • B29C48/50—Details of extruders
  • B29C48/76—Venting, drying means; Degassing means

Definitions

• the present invention relates to a medium for use in pollution control and an apparatus for and method of manufacturing the same.
• the present invention relates to a medium with high bioaffinity and low specific gravity, capable of controlling biomass with ease and treating wastewater and polluted air at high efficiency, and an apparatus for and method of manufacturing the same.
• cellulose-rich materials such as compost, peat moss, wood chips, etc.
• ceramic type materials such as sand, pebbles, pumice, etc.
• synthetic resins such as polyethylene, polypropylene, polystyrene, ABS, etc.
• Cellulose-rich materials provide small and thin particles for the media.
• these media are used to treat a gas-phase wastes which has a large pollution load or a waste water, the growth of microorganisms in the media is too fast to control, thereby clogging the pores inside of the media.
• cellulose-type media are used to treat gas-phase wastes which are low in pollution load.
• cellulose-type media suffer from the disadvantage of being not used for a long period of time not only because their water-content is difficult to control, but because compaction and settling occur during use, deteriorating the air permeation of the media.
• Media comprising pellets molded from ceramic-type materials are excellent in terms of the adsorption of organisms. However, they are produced at high cost. Like cellulose-type media, the ceramic-type media become unworkable to clog the pores of the media when they are applied to the gas-phase wastes which has a large pollution load, or waste water.
• the removal of the microorganisms unduly grown in the media resorts to back-wash with water or air.
• the volume of the medium layer is usually expanded by approximately 40%.
• the volume expansion upon back- wash requires an excess of water compared to the capacity of the facility used, owing to the high specific gravity of the media.
• the flow speed of water used for 40% volume expansion and back- wash of the media must amount to as high as 190 m/hr when the ceramic media have a mean particle size of 6.35 mm in diameter and 10 mm in length. This water speed needs a flow rate of 190 rrrYhr for a cross area of 1 m 2 in the reactor.
• the media are advantageous in that their shape and size can be freely controlled and they can be made to have a specific gravity of 1 or less.
• they are still unsuitable for use in treating wastes of a high pollution load because they are poor in bioaffinity, unlike natural materials such as cellulose- and ceramic-type materials.
• natural materials such as ceramic- and cellulose-type materials, are molded in combination with synthetic materials such as thermoplastic resins, as disclosed in Korean Pat. Laid-Open Publication No. 2000-18194, entitled "Method for preparing media for use in pollution control, using extrusion process".
• an apparatus comprising a first extruder for kneading and extruding a natural material and a synthetic polymeric material; and a second extruder for kneading and extruding a synthetic polymeric material of low specific gravity.
• Each extruder is composed essentially of a cylindrical housing, a screw housed in the cylindrical housing, and an operating means for operating the screw, said cylindrical housing being extended to form a discharge pipe having an outlet, with a gradual reduction in diameter.
• a cutting means for cutting a kneaded mass coming out of the outlet into a predetermined size is also provided to the outlet. Also, the cutting means may be provided with a cooling means for cooling the medium so cut.
• the first extruder and the second extruder are arranged at a right angle or parallel to each other.
• a hole is provided for ventilating the moisture and gas generated during the compression and heating of the natural material and the synthetic polymeric material, whereby the kneaded mass of the natural and synthetic materials can be discharged smoothly.
• a method for manufacturing a medium for use in pollution control comprising the steps of: kneading and extruding a mixture of a natural material and a synthetic polymeric material to form a first region of the medium; kneading and extruding a material of low specific gravity to form a second region of the medium; and locating the second region in the center of the first region.
• the method may further comprises the steps of: ventilating moisture and gas, the moisture and gas being generated during the kneading and extrusion of the natural material and synthetic polymeric material for the formation of the first region; cutting the medium having the first and the second region into a predetermined size; and cooling the cut medium.
• the mixture comprises 45-75 % by weight of a ceramic, 20-40 % by weight of a thermoplastic resin, 0-30 % by weight of sawdust, and 0-5 % by weight of phosphate.
• the material of low specific gravity comprises 95-100 % by weight of a thermoplastic resin and 0-5 % by weight of a foaming agent.
• a medium for use in pollution control comprising: a first region comprising 45-75 % by weight of a ceramic, 20-40 % by weight of a thermoplastic resin, 0-30 % by weight of sawdust, and 0-5 % by weight of phosphate; and a second region comprising 95-100 % by weight of a thermoplastic resin and 0-5 % by weight of a foaming agent, said second region being located in the center of the first region.
• Fig. 1 is a schematic cross sectional view of a medium according to the present invention
• Fig. 2 is a cross sectional view of an apparatus for manufacturing a medium, in accordance with an embodiment of the present invention
• Fig. 3 is a cross sectional view of an apparatus for manufacturing a medium, in accordance with another embodiment of the present invention
• Fig. 4 is a schematic cross sectional view of an outlet used in the apparatuses of Figs. 2 and 3;
• Fig. 5 is a schematic front view of an outlet region provided to the apparatuses of Figs. 2 and 3.
• the medium for use in pollution control of the present invention is divided into two regions: a first region made of a mixture of natural and synthetic polymeric materials; and a second region made of a synthetic polymeric material alone. With a lower specific gravity than the first region, the second region is centrally positioned as a core in a cylindrical sheath structure constituted by the first region.
• a core 3 with a lower specific gravity is surrounded by a surface layer 5 made of a mixture of natural and synthetic materials 5.
• Figs. 2 and 3 there is shown an apparatus for manufacturing the medium.
• the apparatus as shown in Figs. 2 and 3, is generally composed of a first and a second extruder 10 and 20 and a cooling means 33 for cooling molded media 1.
• the cooling means 33 comprises a cooling bath 31 containing cold water, and a conveyer 32 for delivering cooled media 1 from the water to the exterior.
• the first extruder 10 is provided for molding the surface layer of the medium 1, materials for the core of the medium 1 are fed into and extruded from the first extruder 20.
• the first extruder 10 comprises a cylindrical housing 11; a screw 13, housed in the cylinder 11, for mixing and extruding the materials for the surface layer of the medium 1; a hopper 17, provided onto the cylinder 11, for feeding the materials to the screw 13 therethrough; and an actuator for operating the screw 13.
• the second extruder 20 comprises a cylindrical housing 21, a screw 23, a hopper 27, and an actuator, all of which are positioned and function like corresponding parts of the first extruder 10.
• a cutting blade 35 is provided for cutting extrudates from the cylinders 11 and 21.
• the actuators of the first and the second extruder 10 and 20 comprise motors 15 and 25 for driving the screws 13 and 23, and decelerators 14 and 24 for attenuating the driving forces of the motors 15 and 25 and transferring the attenuated driving forces to the screws 13 and 23, respectively.
• a blade 35 provided to the outlets.
• the blade 35 may be moved up and down by a power unit (not shown), as shown in Fig. 5.
• the blade 35 may be set forth in such a way that it moves right and left or is rotated.
• each of the cylinders 11 and 21 defines a closed space in which the materials introduced are mixed and extruded under heat.
• the motor 15 (or 25) and the decelerator 14 (or 24) To one terminus of each of the cylinders 11 and 21 are provided the motor 15 (or 25) and the decelerator 14 (or 24), and the hopper 17 (or 27) is mounted onto the cylinder at a site near the terminal part.
• a hole 12 for ventilating the moisture and gases generated during the mixing and kneading of materials is formed at a site nearer an output device 30 to be explained later, than the hopper 17.
• the first extruder 10 is connected to the second extruder 20 at the other terminal part to which is provided the output device 30 in which the extrudate from the first extruder 10 is conjugated with that from the second extruder 20.
• the output device 30 comprises a first discharge pipe 19 of a predetermined diameter extended from the other terminus of the first extruder 10, with a gradual reduction in diameter, and a second discharge pipe 29 of a predetermined diameter, extended from the other terminus of the second extruder 20, with a gradual reduction in diameter.
• An outlet is formed at the free terminus of each of the first and the second discharge pipes 19 and 29, and the diameter of the first discharge pipe 19 is larger than that of the second discharge pipe 29.
• the second discharge pipe 29 is arranged concentrically with the first discharge pipe 19.
• the second discharge pipe 29 is located within the first discharge pipe 19, along its central axis. Further, the second discharge pipe 29 is shorter than the first discharge 19, so that an outlet of the second discharge pipe 29 is positioned at a longer distance from the cutting blade 35 than is an outlet 19a of the first discharge pipe 19. On the inner surface of a terminal part of the outlet 19a, as shown in Fig. 4, grooves 18 are formed, so as to enlarge the surface area of the media 1 coming from the first discharge pipe 19. Any arrangement may be applied to the first and the second extruder 10 and
• the first and the second extruder 10 and 20 are arranged such that the cylinder 11 is at right angles to the cylinder 21, as shown in Fig. 2, or is parallel to the cylinder 21, as in Fig. 3.
• the materials to be fed into the first extruder 10 to constitute the surface 5 of the medium 1 comprises 45-75 % by weight of a ceramic, 20-40 % by weight of a thermoplastic resin, 0-30 % by weight of sawdust, and 0-5 % by weight of phosphate.
• the ceramic material suitable in the present invention is selected from the group consisting of powders of natural ores (crushed rock), fly ash generated upon incineration of wastes, and mixtures thereof.
• the natural ores include perlite, celite, and zeolite.
• the ceramic material is preferably limited to 50 meshes in size as it passes through the first discharge pipe 19 surrounding the second discharge pipe 29.
• the thermoplastic resin may be exemplified by polypropylene, polyethylene, or mixtures thereof.
• the thermoplastic resin is preferably used in an amount of 20 to 40 % by weight. For example, when the content of the thermoplastic resin is below 20 % by weight, the medium 1 is too poor in strength to properly fulfill its role. On the other hand, a content more than 40 % by weight of the thermoplastic resin makes the medium 1 poor in bioaffinity.
• sawdust is preferably 20 meshes or less in size. Its content in the medium is limited to up to 30 % by weight. Sawdust turns brown when it is heated within the first extruder 10 by the external heater. The brown color is eluted into the water which has been in contact with the medium 1 for a long period of time, so that the water must be decolorized if too much sawdust is used. Additionally, sawdust is carbonized upon heating, generating a lot of gas. Thus, if the sawdust content is over 30 % by weight, the gas is generated in abundant quantities sufficient to remain within the first extruder 10 even if it is ventilated out through the hole 12.
• the core 3 of the medium 1 comprises 95-100 % by weight of a thermoplastic resin and 0-5 % by weight of a foaming agent.
• This thermoplastic resin like the resin used for the surface layer 5 of the medium 1, is selected from the group consisting of polypropylene, polyethylene and mixtures thereof. Together with the foaming agent, the thermoplastic resin is melted in and extruded from the second extruder 20.
• thermoplastic resin in the first extruder 10 is melted by the heat from the heater and the frictional heat generated according to the rotation of the screw 13, and kneaded with the other materials.
• thermoplastic resin in the second extruder 20 is melted and optionally kneaded with the foaming agent.
• the inside of each cylinder is maintained at 150-250 °C.
• the materials are kneaded and advanced by the screw 13, with concurrent production of moisture and gas. These are ventilated out of the first extruder 10 through the hole 12.
• the kneaded mass of the thermoplastic resin and foaming agent is discharged from the second extruder 20 through the outlet as the screw 23 is operated.
• the kneaded mass from the second extruder 20 is conjugated with the kneaded mass from the first extruder 10, which is to form the surface layer 5 of the medium 1, in the output device 30.
• the conjugation is conducted in such a way that the kneaded mass from the second extruder 20 is surrounded by the kneaded mass from the first extruder 10.
• the conjugate in which the masses kneaded in the first and the second extruder 10 and 20 form a surface layer 5 and a core 3 is discharged from the outlet 19a of the first extruder 10 with the surface being rugged by the grooves 18.
• the medium 1 is increased in surface area.
• the thermoplastic resin responsible for the core 3 of the medium 1 is foamed to form closed pores in the central region of the medium 1. The closed pores greatly lower the specific gravity of the medium 1.
• the kneaded mass for the surface layer 5 of the medium 1 is bubbled by the gas remaining in the cylinder.
• the conjugate As the conjugate is advanced to the exterior of the extruder, it is cut into chips of a predetermined size by the cutting blade 35, and the chips are dropped into the cooling bath 31. After being cooled in the cooling bath 31, the chips 1 are delivered by the conveyer 32 into a predetermined place.
• the medium 1 of the present invention shows excellent affinity for organisms, as well as ranging, in specific gravity, from 1 to 1.2. Additionally, the medium 1 is excellent in terms of air permeability. Also, even after being in contact with water, the medium is found to not allow the elution of color or harmful materials into the water therefrom.
• the medium of the present invention can be usefully applied for the treatment of wastewater of high pollution load, as well as for the purification of polluted air. Further, over conventional media, the medium of the present invention has advantages in that it is applied to a biofilter to control the biomass with ease, and the manufacturing apparatus is simple and can be operated with ease and at low cost. Furthermore, with the rugged surface area by the grooves 18 of the first discharge pipe 19, the medium 1 can accommodate more microorganisms. The closed pores in the medium 1 enhance its air permeability and thus the treatment efficiency. Also, when being applied for the treatment of air pollution, the pores act to reduce the loss of the gas pressure exerted against the medium, thereby lowering the operating energy consumption.
• media for use in pollution control can be produced, showing high bioaffinity and a low specific gravity, at low cost and with ease.
• the media of the present invention show high constant treatment efficiency with no clogging problems.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Chemical & Material Sciences (AREA)
• General Chemical & Material Sciences (AREA)
• Environmental & Geological Engineering (AREA)
• Analytical Chemistry (AREA)
• Health & Medical Sciences (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Manufacturing & Machinery (AREA)
• Biomedical Technology (AREA)
• Biological Treatment Of Waste Water (AREA)
• Immobilizing And Processing Of Enzymes And Microorganisms (AREA)

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Citations (8)

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• 2001
  • 2001-03-08 KR KR10-2001-0012082A patent/KR100431542B1/ko not_active IP Right Cessation
• 2002
  • 2002-03-06 WO PCT/KR2002/000383 patent/WO2002070103A1/en not_active Application Discontinuation

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