JP2593139B2 - Aqueous waste liquid primary molding equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for efficiently dewatering and preliminarily forming aqueous waste liquid obtained from fibrous waste such as paper waste.

[0002]

2. Description of the Related Art In a paperboard manufacturing plant, a mixture of mainly kraft pulp and waste paper is mainly used as a raw material for paperboard, which generates various papermaking wastes in the paperboard manufacturing process. For example, a large amount of knot (pulping) residue is generated during the production of kraft pulp, while pulper residue is generated when disintegrating waste paper or pulp. Scrap and terminal sludge are generated.

[0003] In these paper wastes, some knot residues and cleaner residues are used as raw materials for lower grade paper, terminal sludge is recycled to a papermaking plant, and chipper dust and the like are used as fuel for boilers. Most of the waste is not economically and effectively treated,
In addition, since it is generated in a very large amount, it is difficult to deal with it.

[0004] In particular, papermaking waste such as pulper chips generated when disintegrating used paperboard is used in the case of gum tape, vinyl tape, vinyl acetate adhesive, plastic film, spelling needle, earth and sand which have adhered to a paper container or a paper bag. Therefore, there is no suitable disposal method other than landfill, and this disposal method is costly and is accused of causing pollution.

[0005] Furthermore, as fibrous wastes, papers shredded by a shredder so as to prevent unnecessary documents from being taken outside in government offices and large companies, etc.
This has increased dramatically with the recent promotion of OA. The paper cut with a shredder is only a few mm wide and only a few tens of mm long.Since this paper is impregnated with a sizing agent or melamine resin, or has a vinyl coating,
Currently, only incineration or landfill methods are used.

[0006]

As a method for treating fibrous waste, there is, for example, Japanese Patent Publication No. 56-11581. Since the method described in this publication does not include a step of previously crushing the fibrous substance (pulp material, etc.) which is the main component of the waste, it is not possible to impart practical mechanical strength to the obtained fiberboard. Practically difficult. When a core is produced from a sol-like substance only by performing preforming and hot pressing as in this method, the entire production time becomes extremely long, which is extremely uneconomical.

[0007] The specification of Japanese Utility Model Laid-Open No. 55-116151 discloses that a form material for a concrete foundation pile is manufactured using papermaking waste as a raw material.
In this manufacturing process, asphalt emulsion and sodium sulfate were added to papermaking waste, dewatered by a round paper machine, and immediately heated and pressurized in a mold for about 5 minutes, or poured into a dehydration mold and vacuum-dewatered. After that, it is heated and compression-molded by a hot-press mold.

[0008] As in the above method, if heating and pressing are performed immediately after dehydration at a stage where the water content exceeds about 50%, moisture is likely to be enclosed in a mold material as a product. As a result, the heating time of the hot press mold required for drying becomes longer, the amount of electricity used extremely increases, and it is uneconomical. Becomes virtually impossible.

The present invention has been proposed in order to improve the above-mentioned problems concerning the treatment of fibrous waste discharged in large quantities from a paper mill or the like. An object of the present invention is to provide an apparatus for dehydrating and forming an aqueous waste liquid obtained from a fibrous waste in two stages in order to process the fibrous waste quickly and in a large amount.

[0010]

In order to achieve the above-mentioned object, a primary molding apparatus 10 according to the present invention has a large number of through-grooves 17 in a front wall 16 and a wire mesh 18 stretched on the surface thereof. Receiving plate 15 and the first pressing plate 1 arranged on the receiving plate
1, a mold frame 19 having an inner diameter substantially equal to the outer diameter of the front wall 12 and a plurality of through grooves 13 in the front wall 12 and a wire mesh 14 on the surface thereof.
And a flat second pressurizing plate (not shown).

The aqueous waste liquid to be fed into the apparatus of the present invention is obtained by removing metal pieces, earth and sand, and the like from the fibrous waste, and then disintegrating the pieces into small pieces to increase the fluidity at a predetermined concentration. Regarding the aqueous waste liquid to be used, when a binder, a waterproofing agent and the like are mixed with the crushed fibrous waste, the concentration is preferably set to about 2 to 4% by weight in order to enhance the fluidity.

After adding a binder, a waterproofing agent, etc. to this aqueous waste liquid, it is poured into a mold 19 of a primary molding device 10 as shown in FIG. Preliminarily dewatered from the through-grooves 13 and 17 of the pressing plate and the receiving plate 15, and then dehydrated at a relatively high pressure using a flat second pressing plate and removing the mold frame 19 to form a flat plate. . When the aqueous waste liquid is solidified in the primary molding, the water content of the obtained primary molded plate is reduced to about half.

[0013] As described above, the moisture content of the primary molded plate is reduced to about half, but since the moisture content is still high, drying is performed by a desired heating device such as an infrared device or hot air heating. The infrared device to be used is generally a dark infrared device, but a far infrared device may be used in some cases. After passing through the infrared device, the moisture content of the primary molded plate is about 22 ~
It drops to 25%.

[0014] In the apparatus of the present invention, it is preferable to provide a pipe for returning a filtrate or a washing liquid discharged from the primary molding apparatus to a mixing tank or a crushing tank via a tank. With such a closed circuit, the amount of waste liquid discharged from the apparatus of the present invention is reduced as much as possible, thereby preventing the occurrence of pollution.

[0015]

The aqueous waste liquid is solidified by the apparatus of the present invention,
The water content of the obtained primary molded plate is about half, preferably about 40 to 4
5% and its thickness is reduced to about 40-45% at inflow. At this time, since the water content of the primary molded plate does not exceed about 50%, the heating time in the next moisture evaporation step can be relatively short, and the amount of electricity used can be small.

The apparatus of the present invention can effectively treat fibrous waste, for example, pulper waste generated when pulp or waste paper is disintegrated, various screen wastes, cleaner wastes, and the like. OA-related waste such as used fax paper and copy paper may be used. In the apparatus of the present invention, even if the fibrous waste contains a gum tape, a vinyl tape, a vinyl acetate adhesive, a plastic film, or the like, it can be treated.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A plant including the apparatus of the present invention will be described in the order of steps with reference to FIG. Pulper waste, various screen waste and cleaner waste, which are high in solid waste in papermaking waste 1
In order to enhance the quality of the fiberboard and the fluidity of the aqueous waste liquid, the first is put into the crushing tank 2 and crushed into small pieces (for example, about 5 mm or less in length). In the crushing tank 2, the contents are agitated and circulated through one or two wet crushers 3 (for example, a trade name of Sulzer Pump, manufactured by Komatsu Zenoa). From the bottom 4 of the crushing tank 2, metal pieces such as spelling needles that cannot be crushed and earth and sand are removed.

The crushed contents generally pass through a cyclone 5 via a transfer pump (not shown), where the remaining metal pieces, earth and sand, etc. are completely removed, and then a screen is removed from the cyclone as required. And into the mixing tank 6 via a roller dehydrator (not shown). Chip-shaped knot residues and various sludges that do not need to be crushed may be directly charged into the mixing tank 6 as desired.

In the mixing tank 6, the concentration of the aqueous waste liquid is set to about 2 to 4% by weight by the concentration measuring device 7 to increase the fluidity of the aqueous waste liquid and to add a binder, a waterproofing agent and the like from the chemical tank 8. And stir vigorously. As an example, the binder is a thermosetting phenolic resin (for example, SK agent, trade name, manufactured by Dainippon Ink and Chemicals, Inc.), and the water-resistant agent is a paraffin-based emulsion (for example, trade name WR + N liquid, manufactured by Dainippon Ink and Chemicals, Inc.) ).

The addition amount of the thermosetting phenolic resin is
It is about 2 to 8 parts by weight based on 100 parts by weight of the aqueous waste liquid. Generally, the larger the amount of the aqueous waste, the higher the mechanical strength of the fiberboard. However, when the amount exceeds a predetermined amount, the mechanical strength does not increase. And if it is less than the predetermined amount, it cannot be used as a hard fiberboard. On the other hand, the addition amount of the water-proofing agent is 10% of the absolute dry amount of the aqueous waste liquid.
It is about 1 to 3 parts by weight with respect to 0 parts by weight, and within this range, it is effective to maintain the predetermined water resistance of the fiberboard.
In this case, in order to further fix the binder and the waterproofing agent, an appropriate amount of sodium sulfate is added to adjust the pH value of the aqueous waste solution to 4.5 to 5.5.
It may be adjusted to 0, and a paint or the like may be added from the chemical tank 8 as desired.

The aqueous waste liquid thus obtained is a sol-like substance using water as a dispersion medium, and is sent to the raw material tank 9 via, for example, a centrifugal pump (not shown). The raw material tank 9 is agitated, and then the aqueous waste liquid is fed into the primary molding apparatus 10 via a measuring tank (not shown) as required.

In the primary molding apparatus 10 of the present invention, the upper first pressing plate 11 has a large number of through-grooves 13 in the front wall 12, and a wire mesh 14 is stretched on the surface of the front wall. The first pressure plate 11 squeezes water in the direction of arrow V by a vacuum pump (not shown). A large number of through-grooves 17 are also provided on the front wall 16 of the receiving board 15, a wire mesh 18 is stretched on the surface of the front wall, and an inner diameter substantially equal to the outer diameter of the first pressure plate 11 on the receiving board 15. And the filtrate falling from the through groove 17 is discharged in the direction of arrow F.

The aqueous waste liquid is supplied to the input port 20 as shown by the arrow L.
From inside the mold 19. The aqueous waste liquid 21 in the mold 19 is 2
In the first stage, the first pressure plate 11 is moved in the direction of arrow D, for example, and the surface pressure is about 5 to 10 kg / cm.
Dehydrate with ² . Then, in the second stage, a flat plate-shaped second pressure plate (not shown) is used, the mold 19 is removed, and dehydration is performed at a high pressure of about 10 to 30 kg / cm ² to form a flat plate. As a result, the water content of the obtained primary molded plate was about 50%.
Hereinafter, it is preferably about 40 to 45%, and its thickness is about 40 to 45% at the time of inflow.

The filtrate discharged by the primary molding apparatus 10 is sent to a filtrate tank 22 (FIG. 2), and is returned from the filtrate tank to a mixing tank 6 via a transfer pump (not shown). Release as wastewater. Further, the washing water used in the primary molding apparatus 10 is sent to the filtration tank 23 and returned from the filtration tank to the crushing tank 2 via a transfer pump (not shown).

Since the obtained primary molded plate still has a high water content, it needs to be subjected to a water evaporation treatment.
Is preferably passed. In this moisture evaporation method, an infrared device such as a dark infrared device is used, and the dark infrared device (for example, product name: Infrastein, manufactured by Nippon Insulators Co., Ltd.)
It heat-drys to 00-250 degreeC. Instead of an infrared device,
Drying may be performed by hot air heating using a steam heat source, but the dark-infrared ray device is superior in terms of production efficiency and equipment area. After passing through the heating furnace 24, the water content of the primary formed plate drops to about 22 to 25%.

The primary molded plate after the water evaporation treatment has an additional 2
The secondary molding is performed by the secondary molding device 25 to a specified thickness. As the secondary molding device 25, for example, a known hot multi-stage press is used, and the temperature of the hot plate of the press is 170 to 18
The temperature is adjusted to about 0 ° C. and the surface pressure is adjusted to about 20 to 30 kg / cm ² . By the secondary molding, the water content of the fiberboard becomes 10% or less.

The obtained single-layer fiberboard 28 is sequentially placed in the slitter 2
6 is trimmed, loaded on the auto stocker 27 and stored in the warehouse. Store in the warehouse for 10-15 days,
It may be shipped after adjusting the humidity appropriately.

As shown in FIG. 3, about 20 to 30% by weight of gum tape, vinyl tape, vinyl acetate-based adhesive, plastic film, and the like in papermaking waste remain in the single-layer fiberboard 28 in the form of small pieces. However, these are mostly melted in the high-temperature heating / pressing step, and serve to increase the mechanical strength of the fiberboard 28 as the fusion material 29.

The fiber board 28 contains various fibrous solids 30 as a main component and has properties substantially similar to kraft paper, so that it has excellent heat insulation and sound insulation properties, and the presence of a water resistant agent. It is also excellent in water resistance and moisture resistance. Further, the fiber board 28 does not change its shape even when boiled in hot water of 100 ° C. for 2 hours, can be cut with a saw, has excellent holding power for nails, and has good cosmetic paint even when surface coating is performed. It does not peel and stretch.

The fiberboard 28 is generally a single layer having a thickness of 2
Up to 15 mm, substantially according to JIS-A59
07, which is equivalent to hard fiberboard specified in
When a special treatment is performed with a resin or the like, the bending strength can be further increased. In addition, when used mainly for a pallet girder or the like for which pressure resistance is a target, the bending strength does not need to be so large, so that it can be formed to a thickness of about 50 mm or less.

Next, a more specific embodiment using the apparatus of the present invention will be described. Example 1 In order to test-produce a 2.5 mm-thick fiberboard, 5 kg of pulper waste (absolutely dry, the same applies hereinafter) and 5 kg of Jansson screen waste generated in the paperboard manufacturing process are used. These are put into a crushing tank containing 340 liters of water, and crushed for about 10 minutes by a crusher (trade name: Sluzer pump).
It becomes a small piece with a length of about 5 mm. This aqueous waste liquid is put into a mixing tank, a thermosetting phenolic resin (trade name SK agent) is added in an absolutely dry amount of 5% by weight, stirred for 10 minutes, and then a paraffin emulsion (trade name WR + N liquid) is added. After stirring for 5 minutes, 3% by weight of absolutely dry sodium sulfate is added and stirred.

68 liters of the obtained aqueous waste liquid is fed into a mold (a horizontal 975 × length 975 × height 200 mm) of a pressure press as a primary molding apparatus, and is subjected to about 25 kg at a surface pressure of 5 kg / cm ^2.
Then, pressure is applied at a surface pressure of 15 kg / cm ² for about 25 seconds. The obtained primary molded plate has a thickness of 3.9 mm and a weight of 3.7K.
g, water content 45%.

The primary molded plate was passed through a heating furnace of a dark-infrared ray device (trade name: Infrastein) to obtain a water content of 1.1.
The amount of electricity used when evaporating a liter is 1 KW / min. Next, secondary molding is performed, and the hot press of the secondary molding device is performed by hot pressing with a heat source of steam, a hot plate temperature of 180 ° C., and a surface pressure of 20 kg / cm ² for about 2 minutes. The final product has a moisture content of around 8%, and its dimensions are 975 x 975
X Thickness 2.5 ± 0.5 mm.

The physical properties of the fiberboard are measured according to JIS-A590
It is as follows when measured according to 5-A5907.

[0035]

[Table 1] Note) The average value of No. 1 to No. 3 up to the moisture content of the test items.

In the hard fiberboard S200 specified in JIS-A5907, the standard is a specific gravity of 0.8 or more and a water content of 5-1.
3%, bending strength 200Kg / cm ² or more, water absorption 30%
It is required that the fiberboard of this example passes all criteria.

Example 2 In order to test-produce a fiberboard having a thickness of 12 mm, the same manufacturing apparatus as in Example 1 was used, and 300 liters of the aqueous waste liquid obtained in Example 1 was subjected to a press-forming mold. Send to The pressurized press, the pressure for about 30 seconds pressurized at a surface pressure of 10 Kg / cm ² for about 30 seconds followed surface pressure 20 Kg / cm ^2, a thickness 16 mm, weight 15 Kg, 45% water content of the primary molded plate.

[0038] The primary formed plate was heated through a heating furnace to evaporate 5 liters of water at a used electricity amount of 4.5 KW / min, and then hot pressed at a surface pressure of 20 kg / cm ² to a pressure of about 10 kg / cm ^2.
After hot pressing for one minute, the water content of the final product is around 8%.

The obtained fiberboards all pass the criteria of JIS-A5907.

Example 3 In order to produce 100,000 3 mm-thick fiberboards per month, 70 tons of pulper waste per month (absolute dry weight, the same applies hereinafter), 75 tons of knot waste, 240 tons of terminal sludge,
Use 18 tons of conditioning sludge. The only pulper residue is
Crush in advance in a crushing tank at a rate of 1 m ³ / min.

These raw materials (760 kg / hour) were converted to actual volume 2
Were charged into the mixing vessel of 2m ^3, addition of thermosetting phenolic resin from chemical tank (trade name SK agent) (monthly use of 20 tons) and then paraffin-based emulsion (trade name WR + N solution) (monthly use of 10 tons) Then, the aqueous waste solution is adjusted to pH 4.5 to 5.0 by further adding sodium sulfate.

The water content of the obtained aqueous waste liquid is 96.5%. This aqueous waste liquid is sent to a raw material tank having an actual volume of 22 mm ³ and stirred, and 113 kg of one sheet is measured by a measuring tank.

As the primary forming apparatus, a double wire of a hydraulic pressurization type and a high-pressure press (first-stage output: 120 tons, second-stage output: 350 tons) (manufactured by Yamamoto Iron Works) are used. 920 x 1830 x 68 mm
The first stage has a surface pressure of 7 kg / cm ² , the aqueous waste solution has a water content of 60%, and the second stage has a surface pressure of 20 kg / cm ^2.
, The water content drops to 45%.

The obtained primary molded plate has a weight of 10 kg / sheet, a thickness of 4.4 mm, and a production efficiency of 4 to 10 m / min. This primary molded plate is subjected to a moisture evaporation treatment in a heating furnace using a 50 KW dark / infrared ray device (trade name: Infrastein). The furnace uses 260 KW / hour and a processing capacity of 190 sheets / hour. With this heating furnace, the water evaporation amount of the primary molded plate is 1.5 liters / sheet, and the thickness thereof is 4.0 mm.

As the secondary forming apparatus, a hot multi-stage press (manufactured by Yamamoto Tekkosho) with an output of 350 tons and 10 stages is used, the surface pressure is 20 kg / cm ² , and the hot plate temperature is 170 ° C.
When subjected to secondary molding at a cycle of 20 times / hour, a fiber board having a width of 930 × length 1840 × thickness of 3 mm is obtained. Next, trimming is performed with a slitter at a speed of 8 seconds / sheet, and 910 (horizontal) × 182 (vertical).
A fiberboard of 0 × thickness 3 mm is obtained. The fiberboard is loaded on an auto stocker having a loading capacity of 420 sheets and stored in a warehouse.

The obtained fiberboards all pass the criteria of JIS-A5907.

[0047]

The apparatus of the present invention solidifies the aqueous waste liquid of fibrous waste and lowers the water content of the obtained primary molded plate to about half. This makes it possible to shorten the heating time in the next moisture evaporation step, and the amount of electricity used in the heating furnace is reduced, which is economical. In addition, as a result, the production efficiency of the single-layer fiberboard as the final product is increased, and a large-scale practical plant can be realized.

The single-layer fiberboard of the final product can be used for automobile interior materials, building materials, pallets, noise barriers on highways, fittings, furniture and the like. Japanese Standard (JIS) A590
It is possible to have a quality equivalent to the hard fiber board specified in No. 7, and it is highly practical. This single-layer fiberboard is extremely inexpensive because it conventionally uses fibrous waste, which requires landfill and incineration costs, as a raw material.

The apparatus of the present invention can rapidly and in large quantities treat fibrous wastes that cannot be reused or are extremely uneconomical to be reused, thereby contributing to resource saving effects and preventing pollution. The device of the present invention effectively treats large amounts of fibrous wastes, avoids severe soil and seawater pollution by landfilling or dumping them offshore, and also reduces the amount of landfills that can be properly disposed of. Soaring costs can be substantially prevented.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a main part of a primary molding apparatus according to the present invention.

FIG. 2 is a flow sheet illustrating a process for manufacturing a single-layer fiberboard including the apparatus of the present invention.

FIG. 3 is a perspective view of a single-layer fiber board manufactured by the manufacturing process of FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Primary molding apparatus 11 1st press board 13 Through-groove 14 Wire mesh 15 Receiving board 17 Through-groove 19 Formwork 8 Single-layer fiberboard

Claims (2)

(57) [Claims] 1. A receiving plate having a large number of through-grooves in a front wall and a wire mesh stretched on the surface thereof, and an inner diameter substantially equal to the outer diameter of the first pressure plate disposed on the receiving plate. Having a plurality of through-grooves in the front wall and a wire mesh on the surface thereof, and a second flat plate-shaped press plate. The first press plate is a receiving plate. An aqueous waste liquid primary molding apparatus which is used together with a formwork disposed thereon, and uses a second pressure plate after removing the formwork from the receiving plate. 2. The apparatus according to claim 1, wherein a pipe is provided for returning a filtrate or a washing liquid discharged from the primary molding apparatus to a mixing tank or a crushing tank via a tank.