KR100823151B1 - A multiporous polyurethane foam carrier a method for preparation of the same, and an aeration tank used for fluidized-bed biofilm reactor - Google Patents

Abstract

An aeration tank for a fluidized-bed biofilm reactor, which is filled with a porous polyurethane foam carrier having improved fluidity and wear resistance that is formed in the form of a constant hexahedron with width, length, and height ranging from 3 to 4.5 mm in the amount of 30 to 50% of the apparent volume of the entire aeration tank, is provided to make it not necessary to return carrier sludge, treat wastewater even under a high load condition, and substantially improve the wastewater treatment efficiency ultimately. As a method for preparing a porous polyurethane foam carrier formed in the form of a constant hexahedron with width, length, and height ranging from 3 to 4.5 mm, the method comprises: a first step of supplying an isocyanate compound, a polyol, a catalyst, a silicone surfactant, and a foaming agent to a mixing head and reacting the isocyanate compound, polyol, catalyst, silicone surfactant, and foaming agent to obtain a sponge-shaped porous polyurethane foam carrier; a second step of longitudinally cutting the sponge-shaped porous polyurethane foam carrier to form longitudinal blade marks on the carrier in an equal distance; a third step of laterally cutting the sponge-shaped porous polyurethane foam carrier having the longitudinal blade marks formed thereon to form lateral blade marks on the carrier in an equal distance; a fourth step of finally cutting the polyurethane foam carrier having the longitudinal and lateral blade marks formed thereon to obtain porous polyurethane foam carriers formed in the form of a constant hexahedron with a width, a length and a height ranging from 3 to 4.5 mm; and a fifth step of vacuum-sucking the cut hexahedral porous polyurethane foam carriers to remove fragments therefrom using a mesh net. As an aeration tank for a fluidized-bed biofilm reactor used in wastewater treatment, the aeration tank is filled with a porous polyurethane foam carrier(1) that is formed in the form of a constant hexahedron with a width, a length and a height ranging from 3 to 4.5 mm in the amount of 30 to 50% of the apparent volume of the entire aeration tank, and includes a wedge wire screen(2).

Description

Porous polyurethane foam carrier and method for preparing the same and aeration tank for fluidized bed biofilm reaction apparatus {A MULTIPOROUS POLYURETHANE FOAM CARRIER A METHOD FOR PREPARATION OF THE SAME, AND AN AERATION TANK USED FOR FLUIDIZED-BED BIOFILM REACTOR}

1 illustrates an aeration tank for a fluidized bed biofilm reaction apparatus.

2 shows a wedge wire screen installed in an aeration tank for a fluidized bed biofilm reactor.

3 is a perspective view of an apparatus for cutting a sponge-shaped porous polyurethane foam carrier.

4 is a circular rotary knife bundle for cutting the sponge by cutting the porous polyurethane foam carrier of the sponge shape is arranged at equal intervals in the range of 3 to 4.5 mm on the shaft, and the horizontal, vertical and height of 3 to 4.5 A band knife is shown which finish cuts into a porous polyurethane foam carrier in the form of a regular cube in the range of mm.

<Description of the symbols for the main parts of the drawings>

1: Porous polyurethane foam carrier in hexahedral form with a width, length and height in the range of 3 to 4.5 mm

2, 2 ': wedge wire screen

3: top of aeration tank 4: screen effective area (blinded)

5: diffuser for screen cleaning 6: treated water outlet

10: horizontal axis rotary knife bundle

20: vertical axis rotary knife bundle

30: band knife 40: container 41: transfer plate

42: rail 50: suction pump

A: Sheath line formed vertically by the horizontal axis circular rotating knife bundle.

B: Sheath line formed horizontally by the longitudinal rotary knife bundle.

C: Porous polyurethane foam carrier in the form of a hexahedron having a width, length, and height of 3 to 4.5 mm, which is finished cut by a band knife.

The present invention relates to a porous polyurethane foam carrier in the form of a hexahedron having a constant width, length, and height within a range of 3 to 4.5 mm, and a method of manufacturing the same. Moreover, this invention relates to the aeration tank for fluidized bed biofilm reaction apparatuses used for wastewater treatment.

Conventional microbial carriers used in fluidized bed type biofilm wastewater treatment devices have a disadvantage that not only the wastewater treatment efficiency is lowered due to the accumulation phenomenon, but also the transport of carrier sludge is inevitable.

On the other hand, sponge-like synthetic resins (especially polyurethane) foams have been used as microbial carriers for wastewater treatment by cutting into hexahedron, but if the size of the foam particles is too small, it is easy to be lost, and if the size of the foam particles is too large, the carrier There was a problem that the surface area of contact between the wastewater and the wastewater and the fluidity of the carrier were significantly reduced. Moreover, failure to uniformly cut the sponge-shaped foam carrier to an appropriate size and shape, leaving debris, adversely affects the wear resistance of the carrier.

It is an object of the present invention to provide a porous polyurethane foam carrier in the form of a hexahedron having a constant width, length and height within a range of 3 to 4.5 mm with improved flowability and wear resistance.

In addition, the present invention is a porous cube of polyurethane foam in the form of a regular cube in the range of 3 to 4.5 mm in width, length and height filled with 30 to 50% of the total volume of the aeration tank, wedge wire screen It is an object of the present invention to provide an aeration tank for a fluidized bed biofilm reaction device, which is characterized in that the carrier sludge is not necessary to be transported and the treatment at high load is possible.

The present invention provides a method for preparing a porous polyurethane foam carrier having a hexahedral form in the range of 3 to 4.5 mm in width, length and height, comprising: (a) i) 4,4-diphenylmethane diisocyanate, 2,4 An isocyanate compound selected from the group consisting of -toluene-diisocyanate, 2,6-toluene-diisocyanate and mixtures thereof, ii) polyols having a molecular weight of 3,000-8,000, iii) dimethylcyclohexylamine, tetramethylhexanediamine, pentamethylene A catalyst selected from the group consisting of diethylenetriamine and triethylenediamine, iv) silicon-based foam stabilizers having Si-C bonds or Si-OC bonds, and v) fluorohydrocarbons (HFC), chlorofluorohydrocarbons (HCFC) And reacting by supplying a blowing agent selected from the group consisting of cyclopentane to a mixing head equipped with a stirring rod through each independent line. As such, to obtain a porous polyurethane foam carrier of sponge shape; (b) the horizontal axis circular rotary knife bundle 10, in which the circular knives are arranged at equal intervals within the range of 3 to 4.5 mm, is vertically cut by vertically cutting the sponge-shaped porous polyurethane foam carrier on the shaft. Drawing a scabbard line (A) of the; (c) Horizontally moving the vertical axis circular rotary knife bundle 20, in which the circular knife is arranged at equal intervals within the range of 3 to 4.5 mm, to form a sponge-like porous polyurethane foam carrier having a vertical cut. Cutting horizontally to produce equally spaced sheath lines (B); (d) finishing cutting using a band knife to obtain a porous polyurethane foam carrier in the form of a cube that has a constant width, length, and height within a range of 3 to 4.5 mm; (e) using a pump for inhaling the carrier, suctioning a vacuum into the cut porous polyurethane carrier, and then removing the debris in two steps using a mesh net. Provide a way to.

In the main raw material used in the step (a) of obtaining a sponge-like porous polyurethane foam carrier, the isocyanate compound is 4,4-diphenylmethane diisocyanate or 2,4-toluene-di mixed in an 80/20 ratio. It is preferable that it is isocyanate / 2, 6-toluene diisocyanate (80/20), and it is preferable that a polyol is a polyol containing 2-4 -OH groups (or active hydrogen). Catalysts commonly used for the reaction of isocyanate compounds with polyols are tertiary amine compounds, for example dimethylcyclohexylamine (DMCHA), tetramethylhexanediamine (TMHDA), pentamethylenediethylenetriamine (PMDETA) and Triethylenediamine (TEDA) etc. are mentioned. Silicone foam stabilizers used in the production of polyurethane foams emulsify the raw materials to facilitate mixing, lower the surface tension of the polyurethane foam to help bubble growth, and lower the pressure difference between bubbles to prevent gas diffusion and polyurethane cells. The action of preventing the unevenness of the cell, the stabilization of the polyurethane cell membrane, and the improvement of the fluidity of the foam, and the like. It is preferable that a silicon foam stabilizer has a Si-C bond or a Si-O-C bond. Blowing agents are used to minimize adverse effects on the environment, such as ozone layer destruction, such as fluorohydrocarbon (HFC) (e.g., HFC-245fa, HFC-365mfc, etc.), chlorofluorohydrocarbon (HCFC) (e.g., HCFC-141b) and cyclopentane. Preference is given to using. In addition, additives such as a flame retardant, a chain extender, and a crosslinker may be administered.

As shown in FIG. 3, a device for cutting a sponge-shaped porous polyurethane foam carrier includes a horizontal axis circular rotary knife bundle 10, a vertical axis circular rotary knife bundle 20, a band knife 30, and a transfer. A container 40 with a plate 41, a rail 42, and a suction pump 50 are included. Adopting the principle of cutting the sponge fabric by using up, down, left and right flow knives, the device can achieve higher productivity compared to the press device using a wood die.

In step (b), the cut line A is cut out vertically by the vertical movement of the horizontal axis rotating knife bundle 10, and in step (c), the cut line is cut horizontally by the horizontal movement of the vertical axis rotating knife bundle 20. After (B) is cut out, it is possible to cut uniformly and precisely the porous polyurethane foam in the form of a cube having a width, length, and height of 3 to 4.5 mm by finishing cutting by the band knife 30 in step (d). .

In step (e), a vacuum is sucked into the cut polyurethane cube in the form of a hexahedral porous pump, followed by removal of debris in two steps using a mesh net. Abrasion resistance of the carrier can be improved.

The present invention also provides a porous polyurethane foam carrier in the form of a hexahedron having a width, length and height of 3 to 4.5 mm, which are produced by the above-described method. The smaller the carrier, the better, but if the carrier is smaller than 3 mm, for example, it is difficult to be separated from the treated water by a screen (especially a wedge wire screen), and when the carrier is larger than 5 mm, for example, It is easy to fall. In order to optimize the contact area and fluidity with the waste water and to prevent the carrier from being lost with the treated water, the carrier has a size of 3 to 4.5 mm. On the other hand, since the porous polyurethane foam carrier according to the present invention does not contain an activated carbon component or an adhesive resin component, the manufacturing process is simple.

Reference 1 below shows the results of comparative experiments of the rate of initialization (ΔN concentration over time) according to the size of the porous polyurethane foam carrier using synthetic drainage (containing sugar, fish meat extract, vegetable extract, etc.). will be.

[Reference Figure 1]

The reason for using the rate of mineralization as an index of determination is that the rate of growth of supernovae is slower than that of bacteria which contribute to the removal of organic matters. to be. As shown in the reference figure 1, it can be seen that the processing capacity of the carrier having a width, length, and height of 3 mm is about two times higher than that of the carrier having a width, length, and height of 5 mm.

In addition, the present invention is a porous cube of polyurethane foam in the form of a regular cube in the range of 3 to 4.5 mm in width, length and height filled with 30 to 50% of the total volume of the aeration tank, wedge wire screen It provides an aeration tank for a fluidized bed biofilm reaction apparatus, characterized by having a. The aeration tank converts organic matter into microorganisms or metabolizes microorganisms by contacting the contaminants in the influent wastewater with microorganisms attached to the fluidized bed carrier and mixing them with air using an diffuser. It converts energy and metabolic by-products (eg, carbon dioxide) to remove contaminants from wastewater. The aeration tank installed in the fluidized bed biofilm reaction device for wastewater treatment is filled with 30 to 50% of the total volume of the aeration tank, filled with a porous polyurethane foam carrier in the form of a cube having a width, length and height of 3 to 4.5 mm. And a screen (wedge wire screen). Aeration tanks can be used for both single-sided and front aeration. The wedge wire screen is installed perpendicular to the aeration tank wall to separate the carrier and the treated water. The wedge wire screen has a structure in which the occlusion of the screen can be visually confirmed, and the screen cleaning diffuser is provided at a suitable distance to allow air cleaning. Surplus sludge generated by biodegradation is continuously discharged from the aeration tank by friction with the flow of the carrier.

The present invention is for a biofilm reaction apparatus in which the porous polyurethane foam carrier in the form of a hexahedron having a constant hexahedral shape in the range of 3 to 4.5 mm in width, length and height is improved, and filled with 30 to 50% of the total volume of the aeration tank. By providing an aeration tank, the conveyance of carrier sludge is unnecessary, the treatment at high load is possible, and ultimately, wastewater treatment efficiency can be improved significantly.

Claims (9)

As a method for producing a porous polyurethane foam carrier having a hexahedron shape in the range of 3 to 4.5 mm in width, length and height, (a) i) an isocyanate compound selected from the group consisting of 4,4-diphenylmethane diisocyanate, 2,4-toluene-diisocyanate, 2,6-toluene-diisocyanate and mixtures thereof, ii) molecular weight 3,000 to 3,000 8,000 polyols, iii) a catalyst selected from the group consisting of dimethylcyclohexylamine, tetramethylhexanediamine, pentamethylenediethylenetriamine and triethylenediamine, iv) a silicon foam stabilizer having a Si-C bond or a Si-OC bond And v) supplying a blowing agent selected from the group consisting of fluorohydrocarbon (HFC), chlorofluorohydrocarbon (HCFC) and cyclopentane to the mixing head with a stirring rod through each separate line. By reacting to obtain a sponge-shaped porous polyurethane foam carrier; (b) Vertically cutting the sponge-shaped porous polyurethane foam carrier by vertically moving the horizontal axis circular rotary knife bundle in which the circular knives are arranged at equal intervals within the range of 3 to 4.5 mm on the shaft to cut the equally spaced sheaths. Making step; (c) Horizontal movement of the vertical axis circular rotary knife bundle with circular knives arranged at equal intervals within the range of 3 to 4.5 mm on the shaft, and the longitudinally cut sponge-like porous polyurethane foam carrier is cut horizontally. Equally spaced sheaths; (d) finishing cutting using a band knife to obtain a porous polyurethane foam carrier in the form of a cube that has a constant width, length, and height within a range of 3 to 4.5 mm; (e) using a pump for inhaling the carrier, suctioning a vacuum into the cut porous polyurethane carrier, and then removing the debris in two steps using a mesh net. How to. The method of claim 1, The isocyanate compound is 4,4-diphenylmethane diisocyanate, or 2,4-toluene-diisocyanate / 2,6-toluene-diisocyanate (80/20) mixed at an 80/20 ratio Way. The method of claim 1, The polyol is characterized in that it contains 2 to 4 -OH groups (or active hydrogen). A porous polyurethane foam carrier in the form of a hexahedron formed by the method of any one of claims 1 to 3, wherein the width, length and height are constant within a range of 3 to 4.5 mm. The method of claim 4, wherein The carrier is characterized in that it does not contain an activated carbon component or an adhesive resin component. Aeration tank for fluidized bed biofilm reaction apparatus used for wastewater treatment, Porous polyurethane foam carrier in the form of a hexagonal cube in the range of 3 to 4.5 mm in width, length and height is filled with 30 to 50% of the total volume of the aeration tank, and is provided with a wedge wire screen. Aeration tank made with. The method of claim 6, The aeration tank has a depth of 4 ~ 5m, a depth of width: the ratio of 1: 1 to 2: aeration tank. The method according to claim 6 or 7, The aeration tank is aeration tank, characterized in that both the one-sided aeration and the front aeration. The method according to claim 6 or 7, And the wedge wire screen is installed perpendicular to the aeration tank wall.

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