System and method for recycling thallus fermentation waste liquid

Abstract

An outlet of a fermentation tank is connected with an inlet of a centrifugal machine, a clear liquid outlet of the centrifugal machine is connected with a first inlet of a batching tank, an outlet of the batching tank is connected with a cold material inlet of a first heat exchanger, and a cold material outlet of the first heat exchanger is connected with a material inlet of a second heat exchanger; a material outlet of the second heat exchanger is connected with a material inlet of the maintaining heat exchanger, a material outlet of the maintaining heat exchanger is connected with a hot material inlet of the first heat exchanger, and a hot material outlet of the first heat exchanger is connected with a material inlet of the third heat exchanger. A material outlet of the third heat exchanger is respectively connected with inlet ends of a first branch pipeline and a second branch pipeline through a main pipeline, an outlet end of the first branch pipeline is connected with an inlet of the fermentation tank, and an outlet end of the second branch pipeline is connected with a second inlet of the batching tank. The system improves the reuse water proportion, cancels part of equipment, saves the cost, reduces the risk of hot water leakage, and reduces the operation difficulty and microbiological contamination risk.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of fermentation, and particularly relates to a system and method for recycling of waste liquid from microbial fermentation. BACKGROUND

[0002] In the biological fermentation industry, more and more enterprises choose to use the continuous fermentation mode to improve the utilization rate of equipment, save water and reduce manual operation. The aerobic fermentation needs to sterilize the culture medium in a continuous sterilization mode. Sterilizing the culture medium and the continuous sterilization system is a very critical step in the fermentation process. If the culture medium and the continuous sterilization system are not sterilized completely, the culture medium will be contaminated during the fermentation process, thereby affecting the quality of the fermentation product and causing serious economic losses to the enterprise. Compared with the actual sterilization of the culture medium, the continuous sterilization mode is more suitable for the sterilization and disinfection of the culture medium of a large-volume fermentation tank, and has the advantages of easy automatic control, strong continuity, less damage to the nutritional components of the culture medium, and high utilization rate of the fermentation tank.

[0003] In the continuous fermentation industry, the fermentation concentration is generally low, and the production intensity is high. To solve the problem of low fermentation concentration and considering the actual energy saving and water saving, the proportion of water recycling needs to be increased. The risk of contamination of the recycled water is increased. Through the continuous sterilization mode, the sterilization of the recycled water can be realized.

[0004] However, the existing continuous sterilization system has high requirements for steam, the continuous sterilization temperature fluctuates greatly, and the continuous sterilization process is difficult to control, resulting in a high probability of contamination during continuous sterilization. At the same time, the nutritional components of the culture medium are often unstable due to the fluctuation of the continuous sterilization temperature, further causing a large fluctuation in the fermentation production level. In order to reduce the fluctuation of the continuous sterilization temperature, the usual practice is to preheat the steam to a certain temperature and then introduce it into the culture medium, thereby reducing the temperature difference of the material during the continuous sterilization process. However, this practice requires a long heating time and a large amount of steam, which reduces the efficiency of the continuous sterilization process, increases the energy consumption of the continuous sterilization, and makes the operation more complicated due to the increased number of heating times. The nutritional components of the culture medium are also damaged more, which is not conducive to the stability and improvement of the biological fermentation level. Moreover, in the water sterilization process, the water in the superheated water tank needs to be heated completely, resulting in a large consumption of heat. SUMMARY

[0005] The technical problem to be solved is that the present application provides a system and method for recycling of waste liquid from microbial fermentation, which can effectively solve the problems of the existing continuous sterilization system, such as high requirements for steam, large fluctuation of continuous sterilization temperature, difficult control of continuous sterilization process, high probability of contamination during continuous sterilization, and unstable quality of the nutritional components of the culture medium due to the fluctuation of the continuous sterilization temperature, which further causes a large fluctuation in the fermentation production level.

[0006] Technical solution: In a first aspect, the present application provides a bacteria fermentation waste liquid recycling system, comprising a fermentation tank, an outlet of the fermentation tank being connected with an inlet of a centrifuge, a clear liquid outlet of the centrifuge being connected with a first inlet of a batching tank, an outlet of the batching tank being connected with a cold material inlet of a first heat exchanger, a cold material outlet of the first heat exchanger being connected with a material inlet of a second heat exchanger, a material outlet of the second heat exchanger being connected with a material inlet of a maintaining heat exchanger, a material outlet of the maintaining heat exchanger being connected with a hot material inlet of the first heat exchanger, a hot material outlet of the first heat exchanger being connected with a material inlet of a third heat exchanger, the material outlet of the third heat exchanger being connected with inlet ends of a first branch pipeline and a second branch pipeline through a main pipeline, an outlet end of the first branch pipeline being connected with an inlet of the fermentation tank, an outlet end of the second branch pipeline being connected with a second inlet of the batching tank, the second heat exchanger being provided with a steam inlet, and the third heat exchanger being provided with a circulating water inlet and a circulating water outlet.

[0007] Preferably, a first circulating pump is arranged on a pipeline connecting the clear liquid outlet of the centrifuge with the first inlet of the batching tank.

[0008] Preferably, a second circulating pump is arranged on a pipeline connecting the outlet of the batching tank with the cold material inlet of the first heat exchanger.

[0009] Preferably, a thermometer is arranged on the main pipeline.

[0010] Preferably, a first valve is arranged on the first branch pipeline.

[0011] Preferably, a second valve is arranged on the second branch pipeline.

[0012] In a second aspect, the present application provides a recycling method based on the bacteria fermentation waste liquid recycling system of the first aspect, comprising the following steps: The fermentation liquid enters the centrifuge through the fermentation tank for centrifugal separation, and the obtained clear liquid is pumped into the batching tank by the first circulating pump, the clear liquid in the batching tank is pumped into the first heat exchanger through the cold material inlet by the second circulating pump, the cold material and the hot material are heat exchanged and then enter the second heat exchanger to be heat exchanged with steam, and then enter the maintaining heat exchanger, and after being kept warm for a certain time, the hot material enters the first heat exchanger, in the whole system preheating water consumption process, the first valve and the circulating water inlet of the third heat exchanger are closed, the second valve is opened, so that the hot material flowing out of the first heat exchanger returns to the batching tank through the second branch pipeline for cyclic heating; when the water consumption is completed, the circulating water inlet of the third heat exchanger is opened, the material temperature is reduced to the required temperature of the fermentation tank, the second valve is closed, and the first valve is opened, so that the material enters the fermentation tank through the first branch pipeline.

[0013] Preferably, the temperature maintained by the heat exchanger is 120-130°C, and the holding time is 5-8 minutes.

[0014] Beneficial effects: The system of this invention increases the proportion of recycled water, saves water, and is also suitable for large fermentation tanks; the continuous sterilization process eliminates equipment such as superheated water tanks and continuous sterilization ejectors, saving costs; heat recovery saves steam and reduces the risk of hot water leakage; at the same time, continuous fermentation cultivation can be achieved through instrument-automated control, reducing operational difficulty and the risk of contamination; the system has stable temperature, is easy to control, has good sterilization effect, and stable quality, while being flexible in operation, which is conducive to the stability and improvement of the level of bio-fermentation production technology. It fully utilizes the secondary heat energy in the system, greatly reduces steam consumption, and lowers production costs. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of a microbial fermentation waste liquid recycling system according to the present invention; The numbers in the diagram are: 1. Fermentation tank, 2. Centrifuge, 3. Batching tank, 4. First heat exchanger, 5. Second heat exchanger, 6. Maintaining heat exchanger, 7. Third heat exchanger, 8. First circulating pump, 9. Second circulating pump, 10. First valve, 11. Second valve, 12. Thermometer. Detailed Implementation

[0016] The present invention will be described in detail below with reference to specific embodiments: Example 1

[0017] like Figure 1 As shown, a microbial fermentation waste liquid recycling system includes a fermenter 1. The outlet of the fermenter 1 is connected to the inlet of a centrifuge 2. The clear liquid outlet of the centrifuge 2 is connected to the first inlet of a batching tank 3. The outlet of the batching tank 3 is connected to the cold material inlet of a first heat exchanger 4. The cold material outlet of the first heat exchanger 4 is connected to the material inlet of a second heat exchanger 5. The material outlet of the second heat exchanger 5 is connected to the material inlet of a maintenance heat exchanger 6. The material outlet of the maintenance heat exchanger 6 is connected to the hot material inlet of the first heat exchanger 4. The hot material outlet of the first heat exchanger 4 is connected to the material inlet of a third heat exchanger 7. The material outlet of the third heat exchanger 7 is connected to the inlet ends of a first branch pipe and a second branch pipe respectively through a main pipe. The outlet end of the first branch pipe is connected to the inlet of the fermenter 1. The outlet end of the second branch pipe is connected to the second inlet of the batching tank 3. The second heat exchanger 5 is provided with a steam inlet, and the steam condensate can enter the batching tank 3 for batching and heating. The third heat exchanger 7 is provided with a circulating water inlet and a circulating water outlet.

[0018] A first circulation pump 8 is installed on the pipeline connecting the clear liquid outlet of the centrifuge 2 to the first inlet of the mixing tank 3.

[0019] A second circulation pump 9 is installed on the pipeline connecting the outlet of the above-mentioned batching tank 3 to the cold material inlet of the first heat exchanger 4.

[0020] The above-mentioned main pipeline is equipped with a thermometer 12 for detecting the temperature of the material inside the main pipeline.

[0021] The first branch pipeline is equipped with a first valve 10.

[0022] The second branch pipeline is equipped with a second valve 11. Example 2

[0023] The method for reusing microbial fermentation waste liquid using the recycling system of Example 1 includes the following steps: The fermentation broth enters centrifuge 2 through fermentation tank 1 for centrifugation separation. The resulting clear liquid is pumped into batching tank 3 by first circulation pump 8. The clear liquid in batching tank 3 is pumped into first heat exchanger 4 by second circulation pump 9 through cold material inlet. After heat exchange between cold material and hot material, it enters second heat exchanger 5 for heat exchange with steam, and then enters maintenance heat exchanger 6. After being maintained at 120-130℃ for 5-8 minutes, it enters first heat exchanger 4 as hot material. The hot material enters third heat exchanger 7 through hot material outlet of first heat exchanger 4.

[0024] Close the first valve 10 and the circulating water inlet and outlet of the third heat exchanger 7, and open the second valve 11 so that the hot material flowing out of the first heat exchanger 4 returns to the batching tank 3 through the second branch pipe for circulating heating; when the water is exhausted, open the circulating water inlet of the third heat exchanger 7 to lower the material temperature to the required temperature of 37-40℃ for the fermentation medium, close the second valve 11, and open the first valve 10 so that the material enters the fermentation tank 1 through the first branch pipe for batching. Example 3

[0025] During continuous fermentation, fermenter 1 receives material flowing into the third heat exchanger 7 while simultaneously discharging it to centrifuge 2. The clear liquid after centrifugation in centrifuge 2 enters the mixing tank 3, where inorganic substances are automatically added before entering the system for sterilization. The material flow rate is regulated by adjusting the speed of the circulating pump. Since the temperature inside heat exchanger 6 is maintained at 120-130℃, steam consumption can be reduced by 30%-50%. At the same time, it can maintain high-efficiency continuous fermentation by discharging material from fermenter 1 and feeding fermentation liquid into centrifuge 2, thereby improving equipment utilization and increasing fermentation intensity.

[0026] This invention develops a system and method for recycling bacterial fermentation waste liquid by designing and reusing the heat energy during the continuous sterilization process of the culture medium. This system makes full use of the various heat energies of the continuous sterilization system itself, thereby maximizing energy utilization. This system collects and reuses the steam condensate generated during continuous sterilization. Compared to direct steam heating, this method causes less damage to the nutrients in the culture medium and saves a significant amount of steam. The steam condensate after heat exchange is further used for ingredient preparation, which not only greatly reduces wastewater discharge but also reduces the amount of primary water used. The materials preheated by the steam condensate then exchange heat with the sterilized hot materials through a heat exchanger, further increasing the temperature of the cold materials and cooling the sterilized hot materials, further reducing the amount of cooling circulating water used. When the materials preheated by the two heat exchangers are then heated and sterilized with steam, the steam consumption is greatly reduced, and the temperature is more stable and controllable. The sterilized materials enter the maintenance heat exchanger 6 to maintain the sterilization time. This maintenance heat exchanger 6 has a smaller footprint for the same maintenance time. During the temperature maintenance process, the materials exchange heat themselves, making the temperature more uniform and stable, which is beneficial for killing bacteria and maintaining the stability of the nutrients in the culture medium. This system offers stable temperature control, ease of operation, excellent sterilization effect, and consistent quality. Its flexible operation contributes to the stability and improvement of bio-fermentation production technology. It fully utilizes secondary heat energy within the system, significantly reducing steam consumption and lowering production costs. This system is particularly suitable for large-scale bio-fermentation production applications and demonstrates remarkable advancements.

[0027] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A system for recycling waste liquid from microbial fermentation, characterized in that: The system includes a fermenter (1), the outlet of which is connected to the inlet of a centrifuge (2), the clear liquid outlet of which is connected to the first inlet of a mixing tank (3), the outlet of which is connected to the cold material inlet of a first heat exchanger (4), the cold material outlet of which is connected to the material inlet of a second heat exchanger (5), the material outlet of which is connected to the material inlet of a sustaining heat exchanger (6), and the material outlet of which is connected to the first heat exchanger (4). The heat exchanger (4) is connected to the heat inlet of the first heat exchanger (4), and the heat outlet of the first heat exchanger (4) is connected to the material inlet of the third heat exchanger (7). The material outlet of the third heat exchanger (7) is connected to the inlet of the first branch pipe and the second branch pipe respectively through the main pipe. The outlet of the first branch pipe is connected to the inlet of the fermenter (1), and the outlet of the second branch pipe is connected to the second inlet of the batching tank (3). The second heat exchanger (5) is provided with a steam inlet, and the third heat exchanger (7) is provided with a circulating water inlet and a circulating water outlet.

2. The microbial fermentation waste liquid reuse system according to claim 1, characterized in that: A first circulation pump (8) is installed on the pipe connecting the clear liquid outlet of the centrifuge (2) to the first inlet of the mixing tank (3).

3. The microbial fermentation waste liquid reuse system according to claim 1, characterized in that: A second circulating pump (9) is installed on the pipe connecting the outlet of the mixing tank (3) to the cold material inlet of the first heat exchanger (4).

4. The microbial fermentation waste liquid reuse system according to claim 1, characterized in that: A thermometer (12) is installed on the main pipeline.

5. The microbial fermentation waste liquid reuse system according to claim 1, characterized in that: The first branch pipeline is equipped with a first valve (10).

6. The microbial fermentation waste liquid reuse system according to claim 1, characterized in that: The second branch pipeline is equipped with a second valve (11).

7. A method for reusing waste liquid from bacterial fermentation based on the system described in any one of claims 1-6, characterized in that, Includes the following steps: The fermentation broth enters the centrifuge (2) through the fermentation tank (1) for centrifugal separation. The resulting clear liquid is pumped into the mixing tank (3) by the first circulation pump (8). The clear liquid in the mixing tank (3) is pumped into the first heat exchanger (4) through the cold material inlet by the second circulation pump (9). After heat exchange between the cold material and the hot material, it enters the second heat exchanger (5) to exchange heat with steam, and then enters the maintenance heat exchanger (6). After being kept at a certain temperature for a certain period of time, it enters the first heat exchanger (4) as hot material. The hot material enters the third heat exchanger (7) through the hot material outlet of the first heat exchanger (4). During the entire system preheating process, the first valve (10) and the circulating water inlet of the third heat exchanger (7) are closed, and the second valve (11) is opened so that the hot material flowing out of the first heat exchanger (4) returns to the batching tank (3) through the second branch pipe for circulating heating; when the water sterilization is finished, the circulating water inlet of the third heat exchanger (7) is opened and the material temperature is reduced to the required temperature of the fermentation tank (1). Then the second valve (11) is closed and the first valve (10) is opened so that the material enters the fermentation tank (1) through the first branch pipe.

8. The reuse method according to claim 7, characterized in that, The heat exchanger (6) is maintained at a temperature of 120-130℃ for 5-8 minutes.

Images