CN105436193A - Stirring device capable of realizing cascading fermentation of solid waste and reactor - Google Patents

Abstract

The invention discloses a stirring device and a reactor capable of realizing layered fermentation of solid waste. It includes: a central shaft; a conveying screw for axially pushing materials, which is concentrically fixed on one side of the central shaft and extends tapered from the shaft end to the middle of the shaft; and several stirring blades, which are coaxial with the conveying screw fixed on the other side of the central axis. Based on this stirring device, it can be arranged in a cylinder to form a reactor for solid waste. The layout standard of the stirring blades in the present invention is: no pushing force along the axis of the central axis is generated during the rotation. Thus, a layered fermentation system can be formed in the reactor. This system can greatly reduce the mixing rate of old and new materials, effectively control the residence time of solid materials in the reactor, improve the degradation efficiency of output materials, and improve the quality of final products.

Description

Stirring device and reactor capable of realizing layered fermentation of solid waste

technical field

The invention belongs to the field of solid waste treatment, and in particular relates to a stirring device and a reactor capable of realizing layered fermentation of solid waste.

Background technique

Since the reform and opening up, my country's industrialization and urbanization have developed rapidly, and the production and domestic solid waste production has long ranked first in the world. A scientific and systematic waste management and safe disposal system has not yet been formed, and the cumulative stockpiles have exceeded 20 billion tons. In particular, the current economic development has entered a new normal, and the amount of solid waste generated has surged. For example, the annual production of industrial solid waste exceeds 3 billion tons, and the comprehensive utilization rate is about 60%. The annual increase of 1 billion tons of heavily polluting solid waste has not been effectively disposed of; the annual urban solid waste production exceeds 2 billion tons, and the resource utilization rate is not high. To 50%, many municipal wastes have nowhere to go to landfill. Accelerating the recycling of waste can effectively reduce the environmental pollution caused by waste stockpiling, and will significantly reduce the demand for the development of primary mineral resources, making a huge contribution to the realization of energy conservation and emission reduction goals.

There are many ways to deal with garbage: composting, landfilling, incineration, fluidized bed gas production, garbage fuel, garbage throwing into the sea, garbage farming earthworms, garbage making road materials, garbage making bricks, garbage making petroleum, fiber saccharification technology, waste fiber Feed technology, waste steelmaking, waste biogas production technology, etc., among which the most commonly used treatment methods are composting, landfill, and incineration. Composting is to use microorganisms to degrade the organic matter in the garbage under the control of the moisture content, temperature, ventilation rate, carbon-nitrogen ratio and other process conditions of the garbage, so that it becomes an organic fertilizer with good stability. Composting can realize the recycling of waste resources, so it is a waste disposal method with long-term development prospects.

At present, some biomass solid waste resource reduction technologies and equipment have been developed, but there are problems such as serious mixing of early-stage materials and late-stage materials, uncontrollable residence time, and poor quality of export products, which seriously restrict their market prospects.

For example, the patent with the publication number CN99223087.X discloses a device consisting of a crushing mechanism, a stirring mechanism and a barrel, wherein the crushing mechanism and the stirring mechanism share a main shaft and are installed together in a barrel with a heating element. Although the device can realize the composting function, in the actual use process, since the old and new materials are piled together in the reaction chamber, the layered fermentation cannot be realized, and it can only be used for intermittent fermentation.

Another example is that the patent with the publication number CN201220237876.4 discloses a closed sludge drying fertilizer making machine. Its motor, reducer and mixer are connected in sequence and installed on the frame in the closed housing. The mixer is a double-shaft mixer. . Although the device can realize the continuous advancement of materials, due to the use of the double-shaft mixer, the new materials will be quickly mixed with the old materials, and then discharged out of the fertilizer machine before fully fermented, thus greatly reducing the output cost. degree of fermentation.

The core problem of in-situ fermentation of solid waste is the long residence time of the material and the uneven maturity of the material. , The axial mixing rate between materials is high, resulting in the inability to accurately control the residence time of materials. Therefore, there is an urgent need to develop a layered bio-fermentation reactor that can realize independent and controllable solid waste, and effectively solve the technical problem of efficient and safe resource utilization of biomass waste.

Contents of the invention

In order to overcome the defects of technology or equipment in the background technology, the purpose of the present invention is to provide a stirring device and reactor capable of realizing the layered fermentation of solid waste, which can realize the resource utilization of solid waste with a large reduction and the retention of materials. The time is long and controllable, and the advantages of obtaining high-quality products are obtained.

In order to achieve the above object, the technical scheme adopted in the present invention is as follows:

A stirring device capable of realizing layered fermentation of solid waste, comprising: a central shaft; a conveying screw for axially pushing materials, which is concentrically fixed on one side of the central shaft and gradually moves from the end of the shaft to the middle of the shaft. retractable extension; and a number of stirring blades, which are coaxially fixed with the conveying screw on the other side of the central axis. The stirring device is fixed in the reactor, and the material entering the reactor is pushed along the tapering direction through the conveying screw to reach the area where the stirring blade is located. Stirring paddles stir the material to make it fully mixed and fermented. Finally, the fermented material is output to the outside of the reactor to realize continuous processing.

Preferably, the central shaft is a hollow shaft. The hollow shaft can greatly reduce the weight of the stirring device.

As a preference, the layout standard of the several stirring blades is: no pushing force along the axis of the central axis is generated during the rotation. During the feeding process, if the feeding is stopped, the conveying screw will not generate a pushing force on the material pile in the reactor, but it will be pushed to the stirring blades and only receive the circumferential agitation of the stirring blades, but will not go further. is pushed outward. Therefore, the incoming materials of the same batch will be concentrated in a fixed area and will not be mixed with other batches of materials. When the previous batch of incoming materials is fermented to a certain extent, further materials can be added to the conveying screw, and new materials can be used to push the fermented materials outward, forming a layered fermentation system in the reactor. This system can greatly reduce the mixing rate of old and new materials, effectively control the residence time of solid materials in the reactor, improve the degradation efficiency of output materials, and improve the quality of final products.

In order to increase the agitation rigidity of the agitation blade and improve the anti-disturbance strength and rigidity, as a further preference, the cross section of the agitation blade is rhombus, and the long axis of the rhombus is parallel to the axis of the central axis. When stirring, the stirring paddle contacts the material with the largest surface, and fully stirs the material around the paddle to make it ferment evenly.

As a preferred implementation of the stirring blades, the several stirring blades are arranged on different radial planes of the central axis, and the paddles formed by the stirring blades on each plane are straight blade open turbine type. . The paddles distributed in this form make the filler flow radially, and there is almost no axial flow, so the axial mixing between new and old materials is minimized.

As a further preference of the above implementation, the number of stirring blades on different radial planes is equal and the projections along the axial direction of the central axis overlap. That is, the postures of the stirring blades on different radial planes arranged on the central axis are the same, and there is no misalignment between the blades. Misaligned paddles will also cause the material to be propelled in a discontinuous jump, increasing the axial mixing rate of the material.

As another further preference of the above implementation manner, the different radial planes are equidistant from each other. This enables the material to be fed at a relatively stable rate, and the reaction of each stage is relatively uniform, which is easy to control.

Another object of the present invention is to provide a reactor capable of realizing layered fermentation of solid waste based on the above stirring device. The reactor includes a cylinder and a stirring device in any of the aforementioned preferred modes. The central axis is concentrically arranged in the cylinder. The cylinder is provided with a feed inlet near the conveying screw and a discharge outlet near the stirring blade. The reactor can realize the formation of a layered fermentation system through a stirring device with a special structure, and improve the quality of export products.

As a preference of the reactor, both sides of the cylinder are sealed by detachable covers. The use of the cover can facilitate the installation, cleaning and maintenance of the reactor.

As another preference of the reactor, both ends of the central shaft are supported by supports, and one side of the central shaft is connected with a driving device to realize rotation. The central shaft rotates intermittently at a speed of 3-7r/min.

Compared with background technology, the beneficial effect that the present invention has is:

The rotor in the reactor involved in the present invention is the core component in the reactor. In addition to the advantages of strong stirring ability and heat exchange ability, the most notable advantage is the common Under the action, the material in the reactor can be advanced step by step, and the mixing of materials in different periods is less, the residence time of solid materials in the reactor can be effectively controlled, the degradation efficiency of materials can be improved, and the quality of final products can be improved.

Description of drawings

Fig. 1 is a structural schematic diagram of a stirring device capable of realizing solid waste layered fermentation;

Fig. 2 is a schematic diagram of a reactor capable of realizing solid waste layered fermentation;

Fig. 3 is a schematic diagram of mixing materials in a uniaxial reactor of the present invention;

Fig. 4 is a schematic diagram of stirring material mixing in a biaxial reactor in the prior art.

In the figure: 1. material inlet, 2. material outlet, 4. cover, 5. cylinder, 6. support, 7. stirring paddle, 8. conveying screw, 9. stirring paddle.

detailed description

The present invention will be further described below in conjunction with drawings and embodiments. It should be noted that the technical features mentioned in the present invention can be freely combined without conflicting with each other, which does not limit the present invention.

As shown in Figure 1, a stirring device that can realize the layered fermentation of solid waste includes: a central shaft 8; a conveying screw 7 for axially pushing materials, concentrically fixed on one side of the central shaft 8, The distribution is symmetrical with the central axis as the axis. The conveying screw 7 extends in a tapered form from the shaft end to the middle position of the shaft. The diameter of the conveying screw 7 near the feed end is large, and the diameter near the stirring blade 9 is small. A plurality of stirring paddles 9 are fixed around the shaft body on the other side of the central shaft 8, and the stirring paddles 9 are coaxial with the conveying screw 7. When in use, the central shaft 8 is fixed in the reactor, and the material is pushed to the position of the stirring blade 9 by the conveying screw 7 . Stirring paddle 9 makes it fully mix and ferment by stirring the material. Finally, the fermented material is output to the outside of the reactor to realize continuous processing. In this embodiment, in order to reduce the weight of the stirring device, the central shaft 8 is a hollow shaft.

During the use of traditional reactors, the biggest problem is that the mixing ratio of new and old materials is too high. Although some materials in the reactor have a high degree of fermentation and maturity, because the new materials are mixed with this part of the materials during the stirring process, so When exporting products, it is inevitable to export a part of materials that have not yet completed the fermentation process. Therefore, in order to solve this technical problem, the layout standard of the stirring blades 9 is: no pushing force along the axis of the central axis 8 is generated during the rotation. The stirring paddle 9 is only used to stir the materials in the circumferential direction, the new materials will not be pushed to the area where the old materials are located, and a layered fermentation system is formed in the reactor. This system can greatly reduce the mixing rate of old and new materials, effectively control the residence time of solid materials in the reactor, improve the degradation efficiency of output materials, and improve the quality of final products.

In this process, considering the need for sufficient stirring, the cross section of the stirring paddle 9 is set to be diamond-shaped, and the long axis of the rhombus is parallel to the axis of the central axis 8 . And the use of diamond-shaped blades can also greatly increase its rigidity and stability, reducing the risk of blade breakage.

The agitating blades of the above-mentioned conditions have multiple layout modes, and the following mode is adopted in the present embodiment: the agitating blades 9 are arranged on different radial planes of the central axis 8, and the agitating blades 9 on each plane form a The paddles are straight blade open turbine type. Specifically, the stirring blades are divided into several groups, and each group is distributed on a plane perpendicular to the axis of the central axis 8 . The blades are all straight blades, and are distributed in a circular array around the shaft in an open turbine style. The angle between the stirring blade and the central axis is 90°, which ensures that the material flows radially at the rear end of the stirring device, and there is almost no axial flow, which greatly reduces the axial mixing ratio and ensures the maturity of the material at different fermentation times.

Although the blade distribution of the straight-bladed open turbine can greatly reduce axial mixing, in the actual test process, the number of blades on different planes or the setting angle are different will still cause a jumpy axial push effect. Therefore, in this embodiment, the number of agitating blades 9 on different radial planes is equal, and the projections along the axis direction of the central axis 8 coincide. That is, the stirring paddles 9 of a certain angle on different radial planes are all located on an axial plane of the central axis 8, and the paddles of other angles are also of the same design. Therefore, during the stirring process, the materials on different radial planes in the reactor are all driven by the stirring blades 9 to move in the same migration law, and the axial displacement is minimized.

The distance between different radial planes provided by the stirring blades can be adjusted according to actual needs. In this embodiment, in order to facilitate the adjustment and control of the operator, the distances between different radial planes are equal.

Based on the above-mentioned stirring device, it is installed in the barrel 5 to form a reactor capable of realizing the layered fermentation of solid waste. As shown in FIG. 2 , the central axis 8 of the stirring device is arranged along the axis of the cylinder body 5 . The cylinder body 5 is provided with a feed inlet 1 near the conveying screw 7 , and a discharge outlet 2 is arranged near the stirring paddle 9 side. The axial length ratio of the conveying screw 7 and the stirring paddle 9 is 1/5-1/8. The material falling from the feed port 1 is conveyed by the conveying screw 7 . Both sides of the cylinder body 5 are sealed by a detachable cover 4 . Both ends of the central shaft 8 are supported by the support members 6 . In this embodiment, the support member 6 adopts a bearing. One side of the central shaft 8 protrudes from the outer side of the cover 4 of the cylindrical body and is connected with the reduction motor to realize rotation. The central shaft 8 rotates intermittently at a speed of 3 to 7 r/min.

The operating principle and process of the reactor of the present invention are as follows:

The collected solid waste enters the reactor through the feed port 1, and the material is pushed by the conveying screw 7 to the position of the stirring blade 9. In the area where the stirring paddle 9 is located, the in-situ fermentation is carried out by controlling the temperature and the ventilation rate. During the fermentation process, the intermittent action of the stirring paddle 9 realizes the strong stirring of the material in the circumferential direction, but the axial mixing effect is weak. In this way, layered fermentation is realized, and the residence time of the fermentation material is effectively controlled.

The core problem of in-situ fermentation of solid waste is the long residence time of the material and the uneven maturity of the material. , The axial mixing rate between materials is high, resulting in the inability to accurately control the residence time of materials. At present, the existing twin-shaft reactors on the market are usually provided with two parallel stirring shafts inside the reactor. In order to make a comparison, the uniaxial reactor and the biaxial reactor of the present invention were calculated and simulated by using EDEM discrete element modeling for their axial mixing ratio. As shown in Figure 3 and Figure 4 (the situation shown in Figure 3 is the combination of two reactors), particles of different shapes represent different batches of materials, and the figure shows the mixing state of the materials after being pushed by the stirring shaft. Through simulation, it is found that the axial mixing rate of the twin-shaft reactor can reach more than 42% while realizing the plug flow of materials; while the axial mixing rate of the single-shaft reactor is only 17%, which is obviously better than that of the double-shaft reactor. shaft reactor. Effectively realize the layered fermentation of materials in the reactor, especially suitable for layered fermentation, the mixing ratio of materials in different periods is small, and at the same time ensure full mixing in the same period, full contact with the medium and microorganisms, precisely control the residence time of materials in each stage, and improve fermentation efficiency , To ensure product quality. Compared with the twin-shaft reactor, the product maturity (seed germination rate) obtained by the single-shaft reactor is more than twice that of the twin-shaft reactor, and can reach more than 50%.

The drawings and specific embodiments of the present invention are only used for those skilled in the art to better understand the essence of the invention, and do not limit the protection scope of the invention. Any technical solution within the spirit of the present invention belongs to the scope of protection.

Claims (10)

1. A stirring device capable of realizing solid waste layered fermentation, characterized in that it comprises: a central axis (8); A conveying screw (7) for axially pushing materials is concentrically fixed on one side of the central shaft (8) and extends tapered from the shaft end to the middle of the shaft; and Several stirring paddles (9) are coaxially fixed on the other side of the central axis (8) with the conveying screw (7). 2. The stirring device capable of realizing the layered fermentation of solid waste according to claim 1, characterized in that, the central shaft (8) is a hollow shaft. 3. The stirring device capable of realizing the layered fermentation of solid waste as claimed in claim 1, characterized in that, the laying standard of the several stirring paddles (9) is: no stirring along the central axis occurs during the rotation. (8) Axial push force. 4. The stirring device that can realize the layered fermentation of solid waste as claimed in claim 3, characterized in that, the cross section of the stirring paddle (9) is diamond-shaped, and the long axis of the rhombus and the central axis (8) Axial parallel. 5. The stirring device capable of realizing the layered fermentation of solid waste as claimed in claim 3, characterized in that, the plurality of stirring paddles (9) are arranged on different radial planes of the central axis (8), And the paddle type formed by the stirring paddles (9) on each plane is a straight blade open turbine type. 6. The stirring device capable of realizing the layered fermentation of solid waste as claimed in claim 5, characterized in that the number of stirring paddles (9) on different radial planes is equal and projected along the axial direction of the central axis (8) coincide. 7. The stirring device capable of realizing layered fermentation of solid waste according to claim 5, characterized in that the different radial planes are equidistant from each other. 8. A reactor capable of realizing the layered fermentation of solid waste, characterized in that it comprises a cylinder (5) and the stirring device according to any one of claims 1 to 7, and the central axis (8) is concentrically arranged on In the cylinder body (5), a material inlet (1) is provided on the side of the cylinder body (5) close to the conveying screw (7), and a material outlet (2) is provided on the side close to the stirring paddle (9). 9. The reactor capable of realizing layered fermentation of solid waste according to claim 8, characterized in that: both sides of the cylinder (5) are sealed by detachable covers (4). 10. The reactor capable of realizing solid waste layered fermentation as claimed in claim 8, characterized in that: both ends of the central axis (8) are supported by supports (6), and the central axis (8) One side is connected with the driving device to realize the rotation; the central shaft (8) rotates intermittently, and the rotating speed is 3-7r/min.