Slurry concentration backwater treatment system and backwater treatment method thereof

Abstract

The invention discloses a slurry concentration backwater treatment system and a backwater treatment method thereof.The slurry concentration backwater treatment system comprises an arc-shaped sieve, a coarse separation backwater bin, a fiber recycling machine, a fine separation backwater bin and a screw press, and a water outlet of the arc-shaped sieve is connected with a water inlet of the coarse separation backwater bin through a pipeline; a water outlet of the coarse separation water return bin is connected with a water inlet of the fiber recycling machine, and a water outlet of the fiber recycling machine is connected with a water inlet of the fine separation water return bin; a slag outlet of the sieve bend is connected with a feeding hole of the screw press through a pipeline; a water outlet of the screw press is connected with a water inlet of the coarse separation water return bin; a slag outlet of the fiber recycling machine is connected with a feeding hole of the screw press through a pipeline; the device has the advantages of simple structure, reasonable layout, high fiber recovery precision and full fiber recovery; the recycled fibers are free of mechanical damage, good in quality, high in return water treatment capacity, stable and reliable in system operation, capable of saving a large amount of water treatment cost and time and the like.

Description

Technical Field

[0001] The invention relates to the technical field of papermaking backwater treatment, in particular to a pulp concentration backwater treatment system and a backwater treatment method thereof. Background Art

[0002] In the papermaking process, there are various filtering, washing and concentration processes. Since there is a certain amount of pulp running in the equipment during the process, the return water in the process has more fiber pulp, which increases the processing pressure of the front-end equipment, resulting in a long and extremely complicated process for the treatment and recovery of papermaking return water.

[0003] Patent publication number CN103130352B discloses a pulp recovery process and equipment, specifically disclosing that a pulp-residue separator is first used to remove impurities such as heavy slag and floating slag, and the banknote paper wastewater after slag removal is sent to a fiber recovery machine for pulp recovery, and the recovered pulp is then flowed from a transition storage tank into a double-screw pulping machine for further concentration treatment; First, the scheme uses a pulp-residue separator (i.e., linear screen) for solid-liquid screening, and the screened solid materials are directly sent away for treatment by a slag collection vehicle, and the screened solid materials contain a large amount of fiber; and the pulp-residue separator is not suitable for return water treatment, because the pulp-residue separator (linear screen) has a large screen hole, and the fibers involved in pulp recovery are mainly materials below 1 mm, and the recovery accuracy is low. The pulp-residue separator does not have the ability to perform preliminary recovery of fiber pulp, which is equivalent to the fiber in the pulp being directly recovered and processed by the fiber recovery machine, and cannot relieve the pressure of the rear fine separation equipment; and the fiber pulp is viscous, and the pulp-residue separator (linear screen) is prone to blockage, and in this scheme, the pulp-residue separator and the double-screw squeezer both need to be rinsed with clean water to prevent the pulp from being blocked and accumulated, which greatly increases the water treatment cost; in this scheme, the return water discharged by the fiber recovery machine is directly discharged into the sewage system without recycling treatment; there is insufficient recovery of fibers in the return water, and the fiber recovery accuracy of the treatment system is low; and the recovered fibers have mechanical damage, poor quality, poor return water treatment capacity, and unstable system operation. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the existing defects and provide a pulp concentration return water treatment system and a return water treatment method thereof. The return water treatment system has a simple structure, a reasonable layout, a high fiber recovery accuracy, and can fully recover the fibers in the return water; and the recovered fibers have no mechanical damage and are of good quality, the return water treatment capacity is strong, the system operates stably and reliably, a large amount of water treatment cost and time can be saved, and the problems in the background technology can be effectively solved.

[0005] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a slurry concentration return water treatment system, comprising an arc screen, a coarse separation return water bin, a fiber recovery machine, a fine separation return water bin and a screw press, the water outlet of the arc screen is connected to the water inlet of the coarse separation return water bin through a pipeline, the water outlet of the coarse separation return water bin is connected to the water inlet of the fiber recovery machine, and the water outlet of the fiber recovery machine is connected to the water inlet of the fine separation return water bin; the slag outlet of the arc screen is connected to the feed port of the screw press through a pipeline; the water outlet of the screw press is connected to the water inlet of the coarse separation return water bin; the slag outlet of the fiber recovery machine is connected to the feed port of the screw press through a pipeline.

[0006] To achieve the above object, the present invention also provides the following technical solution: a slurry concentrated return water treatment method, comprising the slurry concentrated return water treatment system described above, the treatment method comprising the following steps: S1, the return water enters the curved screen for coarse sorting, and the fibers in the return water are pre-dehydrated to obtain return water A and fiber slurry A; S2, the fiber slurry A is transported to the screw press through a pipeline connected to the arc-shaped slag screen outlet, and the screw press dehydrates the fiber slurry A to obtain return water B and fiber slurry C; S3, the return water A is transported to the coarse separation return water bin through the pipe connected to the arc screen outlet, and the return water B is transported to the coarse separation return water bin through the pipe connected to the screw press outlet, and the return water A and the return water B are mixed to obtain the return water C; S4, the return water C is transported to the fiber recovery machine through a pipeline connected to the outlet of the coarse separation return water tank, and the fiber recovery machine extracts the remaining fibers in the return water C to obtain fiber slurry B and return water D that contains almost no fibers; S5, the fiber slurry B is transported to the screw press through a pipeline connected to the slag outlet of the fiber recovery machine, and the screw press dehydrates the fiber slurry B to obtain return water B and fiber slurry C; S6. The return water B obtained in step S5 is again transported to the coarse separation return water tank to obtain return water C, and the return water C is processed again through steps S4 and S5; S7, the return water D is transported to the fine separation return water tank through the pipeline connected to the water outlet of the fiber recovery machine.

[0007] Furthermore, the concentration of the fiber slurry A discharged from the arc screen is 4% to 6%.

[0008] Furthermore, the concentration of the fiber slurry C discharged from the screw press is 25% to 30%.

[0009] Compared with the prior art, the beneficial effects of the present invention are as follows: the pulp concentration return water treatment system and the return water treatment method thereof use the arc screen as a coarse separation device in the return water to quickly and roughly separate the fibers in the return water, and can separate most of the fibers in the return water to relieve the pressure of the rear fine separation device, and the arc screen has no mechanical damage in the process of separating the fibers, and the quality of the fibers can be guaranteed; the fiber recovery machine is used as a fine separation device to ensure that the return water can be used for the front-end process and the full recovery of the fibers; and because the arc screen has removed most of the fibers, the processing pressure of the fiber recovery machine is reduced, and the stability of the operation of the fiber recovery machine is guaranteed; the screw press is used as a concentration device to increase the concentration of the fibers, which is convenient for the storage, transportation and reuse of the fibers, and the return water concentrated by the screw press is recycled and treated by the fiber recovery machine, which further improves the fiber recovery accuracy; the return water treatment system has a simple structure, a reasonable layout, a high fiber recovery accuracy, and fully recovers the fibers in the return water; and the recovered fibers have no mechanical damage and are of good quality, the return water treatment capacity is strong, the system runs stably and reliably, and a large amount of water treatment cost and time can be saved. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a schematic diagram of the structure of the present invention; Figure 2 This is a flow chart of the return water treatment process of the present invention.

[0011] In the figure: 1. curved screen; 2. coarse separation return water tank; 3. fiber recovery machine; 4. fine separation return water tank; 5. screw press. DETAILED DESCRIPTION

[0012] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Embodiment 1

[0013] See also Figure 1The present invention provides a technical solution: a pulp concentration backwater treatment system, comprising an arc screen 1, a coarse separation backwater bin 2, a fiber recovery machine 3, a fine separation backwater bin 4 and a screw press 5, the water outlet of the arc screen 1 is connected to the water inlet of the coarse separation backwater bin 2 through a pipeline, the water outlet of the coarse separation backwater bin 2 is connected to the water inlet of the fiber recovery machine 3, and the water outlet of the fiber recovery machine 3 is connected to the water inlet of the fine separation backwater bin 4; the slag outlet of the arc screen 1 is connected to the feed port of the screw press 5 through a pipeline; the water outlet of the screw press 5 is connected to the water inlet of the coarse separation backwater bin 2; the slag outlet of the fiber recovery machine 3 is connected to the feed port of the screw press 5 through a pipeline; Working principle: The return water is subjected to coarse powder selection by the curved screen 1, and the screen material of the curved screen 1 is the pre-dehydrated fiber slurry, which is sent to the screw press 5 through a pipeline; the water separated under the curved screen 1 is sent to the coarse separation return water bin 2, and the water in the coarse separation return water bin 2 is sent to the fiber recovery machine 3 through a pipeline for fine separation, and the fiber slurry separated by the fiber recovery machine 3 is sent to the screw press 5 through a pipeline, and the fiber recovery machine 3 separates the water that is almost free of fiber and enters the fine separation return water bin 4 for standby use; the screw press 5 concentrates and dehydrates the fiber slurry screened by the curved screen 1 and the fiber slurry recovered by the fiber recovery machine 3, and the concentrated water of the screw press 5 is returned to the coarse separation return water bin 2 through a pipeline for circulation treatment, so as to further improve the fiber recovery accuracy; the water in the fine separation return water bin 4 can be reused as flushing and dilution water of this system or flushing and dilution water of the previous stage, and can also be directly discharged into the return water treatment system.

[0014] The pulp concentration return water treatment system disclosed in the present embodiment uses the arc screen 1 as a coarse separation device in the return water to quickly and roughly separate the fibers in the return water, and can separate most of the fibers in the return water to relieve the pressure of the subsequent fine separation equipment. The arc screen 1 has no mechanical damage during the fiber separation process, and the quality of the fibers can be guaranteed; the fiber recovery machine 3 is used as a fine separation device to ensure that the return water can be used for the front-end process and the full recovery of the fibers; and because the arc screen 1 has removed most of the fibers, the processing pressure of the fiber recovery machine 3 is reduced, and the stability of the operation of the fiber recovery machine 3 is guaranteed; the screw press 5 is used as a concentration device to increase the concentration of the fibers, which is convenient for the storage, transportation and reuse of the fibers. The return water treatment system has a simple structure, a reasonable layout, a high fiber recovery accuracy, and can fully recover the fibers in the return water; and the recovered fibers have no mechanical damage and are of good quality, the return water treatment capacity is strong, the system operates stably and reliably, and a large amount of water treatment costs and time can be saved. Embodiment 2

[0015] See also Figure 1-2The present invention also provides a technical solution: a slurry concentrated return water treatment method, including the slurry concentrated return water treatment system described above, the treatment method comprising the following steps: S1, the return water enters the curved screen 1 for rough sorting, and the fibers in the return water are pre-dehydrated to obtain return water A and fiber slurry A; the concentration of the fiber slurry A discharged from the curved screen 1 is 4% to 6%; S2, the fiber slurry A is transported to the screw press 5 through the pipeline connected to the slag outlet of the arc screen 1, and the screw press 5 dehydrates the fiber slurry A to obtain return water B and fiber slurry C; S3, the return water A is transported to the coarse separation return water bin 2 through the pipe connected to the outlet of the curved screen 1, and the return water B is transported to the coarse separation return water bin 2 through the pipe connected to the outlet of the screw press 5, and the return water A and the return water B are mixed to obtain the return water C; S4, the return water C is transported to the fiber recovery machine 3 through a pipeline connected to the outlet of the coarse separation return water tank 2, and the fiber recovery machine 3 extracts the remaining fibers in the return water C to obtain fiber slurry B and return water D that contains almost no fibers; S5, the fiber slurry B is transported to the screw press 5 through the pipeline connected to the slag outlet of the fiber recovery machine 3, and the screw press 5 dehydrates the fiber slurry B to obtain return water B and fiber slurry C; S6. The return water B obtained in step S5 is again transported to the coarse separation return water tank 2 to obtain return water C, and the return water C is processed again through steps S4 and S5; S7, the return water D is transported to the fine separation return water bin 4 through the pipeline connected to the water outlet of the fiber recovery machine 3.

[0016] Furthermore, the concentration of the fiber slurry C discharged from the screw press 5 is 25% to 30%.

[0017] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A slurry concentration return water treatment system, characterized in that: It includes an arc screen, a coarse separation return water bin, a fiber recovery machine, a fine separation return water bin and a screw press. The water outlet of the arc screen is connected to the water inlet of the coarse separation return water bin through a pipeline, the water outlet of the coarse separation return water bin is connected to the water inlet of the fiber recovery machine, and the water outlet of the fiber recovery machine is connected to the water inlet of the fine separation return water bin; the slag outlet of the arc screen is connected to the feed port of the screw press through a pipeline; the water outlet of the screw press is connected to the water inlet of the coarse separation return water bin; the slag outlet of the fiber recovery machine is connected to the feed port of the screw press through a pipeline.

2. A method for treating slurry concentrated water return, characterized in that: The slurry concentration return water treatment system according to claim 1 is included, and the treatment method comprises the following steps: S1, the return water enters the curved screen for coarse sorting, and the fibers in the return water are pre-dehydrated to obtain return water A and fiber slurry A; S2, the fiber slurry A is transported to the screw press through a pipeline connected to the arc-shaped slag screen outlet, and the screw press dehydrates the fiber slurry A to obtain return water B and fiber slurry C; S3, the return water A is transported to the coarse separation return water bin through the pipe connected to the arc screen outlet, and the return water B is transported to the coarse separation return water bin through the pipe connected to the screw press outlet, and the return water A and the return water B are mixed to obtain the return water C; S4, the return water C is transported to the fiber recovery machine through the pipeline connected to the outlet of the coarse separation return water tank, and the fiber recovery machine extracts the remaining fibers in the return water C to obtain fiber slurry B and return water D; S5, the fiber slurry B is transported to the screw press through a pipeline connected to the slag outlet of the fiber recovery machine, and the screw press dehydrates the fiber slurry B to obtain return water B and fiber slurry C; S6. The return water B obtained in step S5 is again transported to the coarse separation return water tank to obtain return water C, and the return water C is processed again through steps S4 and S5; S7, the return water D is transported to the fine separation return water tank through the pipeline connected to the water outlet of the fiber recovery machine.

3. A slurry concentration and return water treatment method according to claim 2, characterized in that: The concentration of the fiber slurry A discharged from the arc screen is 4% to 6%.

4. A slurry concentrated return water treatment method according to claim 2, characterized in that: The concentration of the fiber slurry C discharged from the screw press is 25% to 30%.

Images