Device for enhancing mixed fermentation of sludge and straw by using magnetic biochar

Abstract

The utility model discloses a device for enhancing mixed fermentation of sludge and straws by utilizing magnetic biochar. The device comprises a fermentation tank and a magnet device, a feeding system, a gas outlet and a liquid discharging system are arranged on the fermentation tank; the magnet device has two states of not generating magnetic force to the fermentation tank and generating magnetic force to the fermentation tank; the magnet device is used for not generating magnetic force to the fermentation tank when the fermentation tank performs fermentation and generating magnetic force to the fermentation tank when the fermentation tank finishes fermentation and discharges liquid, so that the magnetic biochar is adsorbed and fixed; and the liquid discharging system is used for discharging the fermentation material without the magnetic biochar in the fermentation tank when the magnet device generates magnetic force on the fermentation tank. The problems that in an existing anaerobic fermentation technology, additives cannot be recycled, and a large amount of methanogens are lost along with discharged materials during semi-continuous fermentation feeding and discharging are effectively solved.

Description

Technical Field

[0001] The utility model belongs to the technical field of biological fermentation, and particularly relates to a device for enhancing the mixed fermentation of sludge and straw by using magnetic biochar. Background Technique

[0002] In China, the annual output of agricultural straws (such as wheat straws, corn straws, cotton straws, etc.) exceeds 1 billion tons, and the annual output of municipal sludge is 60 million - 90 million tons. Most of the solid organic waste has not been utilized for resource and energy, and the unreasonable disposal has also caused serious impacts on the ecological environment. Co - anaerobic fermentation is an effective way to realize the energy and resource utilization of agricultural straws and municipal sludge. It not only solves the pollution problems of straws and sludge, but also provides gas energy (methane), and the biogas slurry and biogas residue after fermentation are also high - quality organic fertilizer components.

[0003] In order to further enhance the gas - producing capacity of the anaerobic fermentation system, adding some nutrient agents that stimulate the growth and reproduction of microorganisms or adsorption materials that fix the growth of microorganisms into the fermentation system is a relatively economical and effective way to increase methane production. Domestic and foreign research on additives in anaerobic fermentation systems mainly involves methods such as adding enzymes or related microbial communities that promote the hydrolysis process, adding nutrients and energy - supplying substances required for methanogens, adding materials that enable the microbial community to be fixed and attached, adding intermediate products of methane fermentation, and adding magnesium ammonium phosphate to relieve ammonia nitrogen inhibition. Among them, biochar additives are a popular research direction in recent years. Adding biochar to the anaerobic fermentation system will bring about an increase in cost. After fermentation, the biochar cannot be recycled, and the loss of biochar occurs during the continuous discharging process, and additives need to be continuously supplemented. Moreover, a large number of methanogens will also be lost during discharging. Therefore, there are certain limitations in improving the fermentation effect only by adding biochar. As a new type of adsorption material, magnetic biochar can effectively retain the magnetic biochar additive in the reactor by applying an external magnetic field during continuous feeding and discharging, reducing the loss of methanogens during the discharging process. At the same time, the introduced magnetic material has also been proven to have the effects of promoting inter - species electron transfer and synergistic catabolism to improve the gas - producing performance of anaerobic fermentation. Magnetite forms an aggregated structure with microorganisms, and recycling also helps to retain more microbial communities. Therefore, the method of using magnetic activated carbon additives to strengthen co - fermentation can improve the anaerobic fermentation performance while realizing the circular economy utilization of additives. Content of the Utility Model

[0004] The purpose of the utility model is to provide a device for enhancing the mixed fermentation of sludge and straw by using magnetic biochar to solve the problems in the prior art that additives cannot be recycled and a large number of methanogens are lost during the semi - continuous fermentation feeding and discharging.

[0005] The object of the present utility model is achieved by the following technical solutions:

[0006] A device for enhancing the mixed fermentation of sludge and straw by using magnetic biochar, comprising a fermentation tank and a magnet device;

[0007] The fermentation tank is provided with a feeding system, an air outlet and a liquid discharging system; the feeding system is used to add a fermentation substrate including sludge and straw, an inoculum and magnetic biochar into the fermentation tank; the air outlet is used to discharge the gas generated during the fermentation process of the fermentation tank;

[0008] The magnet device has two states of not generating magnetic force and generating magnetic force on the fermentation tank; the magnet device is used to not generate magnetic force on the fermentation tank when the fermentation tank is fermenting, and generate magnetic force on the fermentation tank when the fermentation tank finishes fermentation and discharges liquid, so that the magnetic biochar is adsorbed and fixed;

[0009] The liquid discharging system is used to discharge the fermentation material without the magnetic biochar in the fermentation tank when the magnet device generates magnetic force on the fermentation tank.

[0010] Preferably, the magnet device is an electromagnet device, which generates magnetic force when powered on and does not generate magnetic force when not powered on.

[0011] Preferably, the magnet device is arranged at the bottom of the fermentation tank;

[0012] The liquid discharging system is a siphon pipe, and the liquid inlet end of the siphon pipe is located in the upper region near the inner bottom of the fermentation tank.

[0013] Preferably, a control valve is arranged on the siphon pipe.

[0014] Preferably, the device provided by the present application further comprises a storage device, and the storage device is communicated with the liquid outlet end of the siphon pipe.

[0015] Preferably, a stirring device is arranged in the fermentation tank.

[0016] Preferably, a slag discharging port is further arranged at the bottom of the fermentation tank.

[0017] Preferably, the feeding system comprises a fermentation substrate feeding pipe, an inoculum feeding pipe, a magnetic biochar feeding pipe and a water inlet pipe.

[0018] Preferably, the device provided by the present application further comprises a gas collecting device communicated with the air outlet;

[0019] The gas collecting device is used to collect the gas generated during the fermentation process of the fermentation tank.

[0020] Preferably, a gas control system is arranged on the fermentation tank, which is used to control the fermentation atmosphere of the fermentation tank.

[0021] This application uses the co-fermentation of straw and sludge, integrating the respective advantages of the two substrates to achieve stable and continuous fermentation. By adopting the method of recycling magnetic biochar additives, it effectively promotes the activity of methanogens, reduces the dosage of additives, and effectively retains the microbial community enriched on the magnetic biochar additives, effectively solving the problems that additives cannot be recycled in the existing anaerobic fermentation technology and a large amount of methanogens are lost with the discharge during semi-continuous fermentation feeding and discharging. It has high practical value for the resource utilization of organic solid wastes such as straw and sludge. Description of the Drawings

[0022] Figure 1 It is a schematic structural diagram of a device for enhancing the mixed fermentation of sludge and straw using magnetic biochar provided by a preferred embodiment of the present utility model;

[0023] Description of the Reference Numerals:

[0024] 1 - fermentation tank; 2 - magnet device; 3 - siphon; 4 - control valve; 5 - storage device; 6 - stirring device; 7 - slag discharge port; 8 - fermentation substrate feed pipe; 9 - inoculum feed pipe; 10 - magnetic biochar feed pipe; 11 - water inlet pipe; 12 - gas collection device; 13 - gas control system. Detailed Embodiments

[0025] The device for enhancing the mixed fermentation of sludge and straw using magnetic biochar provided by this application, as Figure 1 shown, includes a fermentation tank 1 and a magnet device 2.

[0026] The fermentation tank 1 is provided with a feeding system, an air outlet, and a liquid discharge system. The feeding system is used to add fermentation substrates including sludge and straw, inoculum, and magnetic biochar into the fermentation tank; the air outlet is used to discharge the gas (mainly methane) generated during the fermentation process of the fermentation tank.

[0027] The magnet device 2 has two states of not generating magnetic force on the fermentation tank and generating magnetic force. Specifically: when the fermentation tank is normally fermenting, the magnet device does not generate magnetic force on the fermentation tank, and the magnetic biochar is in a free state, capable of fully mixing with other fermentation materials for fermentation. When fermentation ends and liquid discharge is required, the magnet device generates magnetic force on the fermentation tank, so that the magnetic biochar is adsorbed and fixed and cannot be discharged with other fermentation materials, thus reducing the loss of magnetic biochar. Since the magnetic biochar can adsorb and retain more microbial colonies, the loss of methanogens during feeding and discharging is also reduced.

[0028] The liquid discharge system is used to discharge the fermentation materials without magnetic biochar in the fermentation tank when the magnet device generates magnetic force on the fermentation tank.

[0029] The magnet device can use ordinary magnet blocks. Ordinary magnet blocks can continuously generate magnetic force. Therefore, during the normal fermentation process, the magnet blocks should be far away from the fermentation tank. When draining is required after fermentation is completed, the magnet blocks are then brought closer to the fermentation tank to generate an adsorption force on the magnetic biochar, adsorb and fix the magnetic biochar in the fermentation tank, and then use the drainage system to discharge the supernatant liquid without magnetic biochar. This setting requires frequent movement of the magnet blocks, which is inconvenient to operate. Therefore, preferably, the magnet device is an electromagnet device that generates magnetic force when energized and does not generate magnetic force when not energized. The electromagnet device can be set close to the fermentation tank all the time without the need for further movement, and only the on / off of the current needs to be controlled as required.

[0030] To facilitate draining, preferably, the magnet device is arranged at the bottom of the fermentation tank, and the magnetic biochar can be centrally adsorbed at the bottom of the fermentation tank, facilitating the discharge of the supernatant liquid.

[0031] The drainage system can be an overflow port provided on the fermentation tank, and the fermentation material is directly discharged through the overflow port.

[0032] Preferably, the drainage system is a siphon tube 3. The liquid inlet end of the siphon tube 3 is located in the upper region near the inner bottom of the fermentation tank, and further above the adsorbed and fixed magnetic biochar. Setting the siphon tube can make the fermentation liquid drain naturally by using the pressure difference, reduce power consumption, and save costs.

[0033] Preferably, a control valve 4 is provided on the siphon tube 3, and the flow of the fermentation liquid can be conveniently controlled through the control valve 4.

[0034] Further preferably, the device provided in this application further includes a storage device 5. The storage device is communicated with the liquid outlet end of the siphon tube 3 and is used to collect the fermented material.

[0035] Preferably, a stirring device 6 is provided in the fermentation tank 1, which can improve the mixing uniformity of the fermentation material and promote fermentation.

[0036] Preferably, a slag discharge port 7 is further provided at the bottom of the fermentation tank 1, which can be opened when needed to drain the fermentation material completely.

[0037] Preferably, the feeding system includes a fermentation substrate feeding pipe 8, an inoculum feeding pipe 9, a magnetic biochar feeding pipe 10, and a water inlet pipe 11, which are respectively used to add straw and sludge fermentation substrate, inoculum (generally inoculated sludge), magnetic biochar, and fermentation water into the fermentation tank.

[0038] Preferably, the device provided in this application further includes a gas collection device 12 communicated with the gas outlet, which is used to collect the gas generated during the fermentation process of the fermentation tank.

[0039] Preferably, an air control system 13 is provided on the fermenter to control the fermentation atmosphere in the fermenter. Methanogenic fermentation is generally strict anaerobic fermentation, and the atmosphere in the fermenter can be easily controlled through the air control system.

[0040] The working process of the mixed fermentation device provided by this application is as follows:

[0041] First, add fermentation substrates (straw and sludge, and the sludge is a mixed sludge of primary sedimentation sludge and excess sludge) into the fermenter, add inoculum (inoculated sludge, which is anaerobic digestion sludge in a steadily operating anaerobic fermentation reactor) according to a certain ratio, and add water to adjust the solid content in the fermenter. Then add a certain amount of magnetic biochar, and turn on the stirring device to fully mix the fermentation materials. Through the air control system, control the fermentation atmosphere in the fermenter. Turn off the power supply of the electromagnet device, close the control valve of the siphon tube, control the temperature of the fermenter at 36 ± 1 °C, and start fermentation. The gas generated during the fermentation process is discharged through the air outlet and collected by the gas collection device. After the fermentation of this batch of materials is completed, turn on the power supply of the electromagnet device, turn off the stirring device, let it stand for a period of time, and the magnetic biochar is adsorbed at the bottom of the fermenter. Open the control valve of the siphon tube, and the supernatant is automatically discharged through the siphon tube and collected by the storage device. Then add new fermentation substrates to start a new batch of fermentation.

[0042] When agricultural straw and sludge are fermented separately, the fermentation gas production effect is poor due to the characteristics of the raw materials. The co-fermentation of the two can integrate the respective advantages of the two substrates. Through the synergistic effect, it can effectively solve the problem of unbalanced C / N ratio, increase the buffering performance of the fermentation broth, dilute the toxic compounds during the fermentation process, reduce the risks of ammonia nitrogen inhibition and VFA inhibition during the fermentation process, improve the methane production rate and output, and achieve stable and continuous fermentation.

[0043] In order to further enhance the gas production effect of the co-fermentation of the two, this application adds a magnetic biochar additive to the fermentation system. The magnetic biochar additive has both the characteristics that the magnetic material can be recycled and the characteristics that the biochar material can effectively promote gas production. The biochar material can enhance the buffering capacity of the fermentation system, strengthen the interspecies electron transfer efficiency between microorganisms, and increase the methane production and production rate of the fermentation system. At the same time, because the biochar itself has abundant pores, it provides a carrier for the growth of microorganisms and can enrich a large number of methanogens. The preparation of biochar materials requires high-temperature carbonization, and the production cost is relatively high. In the existing usage methods, the biochar additive will be discharged with the discharge during each feeding and discharging, and additional feeding is required for supplementation, increasing the usage cost. In the fermentation device provided by this application, after the biochar is loaded with magnetism, its magnetic properties are used for recycling, reducing the loss of the additive during the feeding and discharging process, and at the same time, a large number of methanogens enriched on the additive are also retained to a large extent, which is conducive to subsequent rapid fermentation and gas production.

[0044] Although the preferred embodiments of the present utility model have been described, those skilled in the art can make additional changes and modifications to these embodiments once they learn the basic creative concept. Therefore, the appended claims are intended to be construed to include the preferred embodiments as well as all changes and modifications that fall within the scope of the present utility model. Obviously, those skilled in the art can make various changes and variations to the present utility model without departing from the spirit and scope of the present utility model. Thus, if these modifications and variations of the present utility model fall within the scope of the claims of the present utility model and their equivalent technologies, the present utility model is also intended to include these modifications and variations.

Claims

1. A device for enhancing the mixed fermentation of sludge and straw using magnetic biochar, characterized in that: Includes a fermentation tank and a magnet device; The fermentation tank is provided with a feeding system, an air outlet and a drainage system; the feeding system is used to add fermentation substrates including sludge and straw, inoculants and magnetic biochar into the fermentation tank; the air outlet is used to discharge the gas generated during the fermentation process of the fermentation tank; The magnet device has two states: no magnetic force on the fermenter and magnetic force on the fermenter. The magnet device is used for not generating magnetic force on the fermenter when the fermenter is fermenting, and generating magnetic force on the fermenter when the fermenter is finished and draining to adsorb and fix the magnetic biochar. The drainage system is used to discharge the fermentation material that does not contain the magnetic biochar in the fermentation tank when the magnet device generates magnetic force on the fermentation tank.

2. The device for enhancing the mixed fermentation of sludge and straw using magnetic biochar as claimed in claim 1, characterized in that: The magnet device is an electromagnet device, which generates magnetic force when powered on and does not generate magnetic force when not powered on.

3. The device for enhancing the mixed fermentation of sludge and straw using magnetic biochar as claimed in claim 2, characterized in that: The magnet device is arranged at the bottom of the fermentation tank; The drainage system is a siphon tube, and the liquid inlet end of the siphon tube is located in the upper area of ​​the inner bottom of the fermentation tank.

4. The device for enhancing the mixed fermentation of sludge and straw using magnetic biochar as claimed in claim 3, characterized in that: The siphon is provided with a control valve.

5. The device for enhancing the mixed fermentation of sludge and straw using magnetic biochar as claimed in claim 4, characterized in that: It also includes a storage device, which is communicated with the liquid outlet end of the siphon tube.

6. The device for enhancing the mixed fermentation of sludge and straw using magnetic biochar as claimed in claim 1, characterized in that: A stirring device is arranged in the fermentation tank.

7. The device for enhancing the mixed fermentation of sludge and straw using magnetic biochar as claimed in claim 1, characterized in that: The bottom of the fermentation tank is also provided with a slag discharge port.

8. The device for enhancing the mixed fermentation of sludge and straw using magnetic biochar as claimed in claim 1, characterized in that: The feeding system comprises a fermentation substrate feeding pipe, an inoculant feeding pipe, a magnetic biochar feeding pipe and a water inlet pipe.

9. The device for enhancing the mixed fermentation of sludge and straw using magnetic biochar as claimed in claim 1, characterized in that: Also included is a gas collecting device in communication with the gas outlet; The gas collecting device is used to collect the gas generated during the fermentation process of the fermenter.

10. The device for enhancing the mixed fermentation of sludge and straw using magnetic biochar as claimed in claim 1, characterized in that: The fermentation tank is provided with an air control system for controlling the fermentation atmosphere of the fermentation tank.

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