A continuous sterilization method without superheated water tank

Abstract

The present invention relates to the technical field of biological fermentation and equipment sterilization, and specifically discloses a continuous sterilization method without a superheated water tank. The water inside the continuous sterilization system is controlled by a circulating pump to form a cycle, and the pressure at the inlet of the circulating pump is controlled by a pressure-stabilizing pump to be constant and greater than the saturated vapor pressure of water at the sterilization temperature. This can ensure the stability of the pressure during the sterilization process, avoid cavitation in the circulating pump, and ensure that the sterilization process reaches the sterilization temperature to ensure the sterilization effect. During the circulation process, the heater heats the water to the sterilization temperature for sterilization. This method eliminates the superheated water tank and its attached instruments and meters, saves investment costs, and reduces safety risks caused by leakage of superheated water. In addition, during the circulation process, due to the reduction in the amount of heated water, some high-temperature steam is also saved, achieving energy and water conservation.

Description

Technical Field

[0001] The invention belongs to the technical field of biological fermentation and equipment sterilization, and in particular relates to a continuous sterilization method without a superheated water tank. Background Art

[0002] In the biological fermentation industry, more and more companies choose to use continuous sterilization (continuous disinfection) to sterilize culture media (materials). Sterilization of culture media and continuous disinfection systems is a very critical step in the fermentation process. If the culture media and continuous disinfection systems are not sterilized thoroughly, the culture media will be contaminated during the fermentation process, thereby affecting the quality of the fermentation products and causing serious economic losses to the company.

[0003] At present, there are two processes for sterilizing the equipment in the continuous disinfection system, one is the steam disinfection process (steam sterilization), and the other is the water disinfection process (superheated water sterilization). Superheated water refers to water that reaches the boiling point (100°C) but does not boil, which can be achieved by pressurization. The water disinfection process uses a superheated water tank to increase the system pressure and sterilize with superheated water. However, the superheated water tank in this process is a pressure vessel, and the equipment manufacturing requirements are high. In addition, in order to ensure the safety of the superheated water tank body, it is necessary to install instruments for detecting temperature, pressure, and liquid level and corresponding control valves on the superheated water tank, resulting in high costs. In addition, after the continuous disinfection system itself is sterilized, when the culture medium is sterilized, the pressure in the feed pipeline will fluctuate greatly at the moment of valve switching. At this time, superheated water vaporizes, causing superheated water to enter the pump in the form of saturated steam, causing pump cavitation, pump damage, and even personal injury. Moreover, in the water disinfection process, all the water in the superheated water tank needs to be heated, which consumes a lot of heat.

[0004] In view of the above problems existing in the existing continuous sterilization process, there is an urgent need for a continuous sterilization method that does not use a superheated water tank and can ensure a constant pressure in the continuous sterilization system. Summary of the invention

[0005] In view of the above-mentioned problems existing in the existing continuous disinfection process, the present invention provides a continuous sterilization method without a superheated water tank. The water inside the continuous disinfection system is controlled by a circulating pump to form a circulation, and the pressure at the inlet of the circulating pump is controlled by a pressure-stabilizing pump to be constant and greater than the saturated vapor pressure of water at the disinfection temperature, so as to ensure the stability of the pressure during the disinfection process and avoid cavitation of the circulating pump. During the circulation process, the heater heats the water to the disinfection temperature for disinfection. This method eliminates the superheated water tank and its attached instruments and meters, saves investment costs, and reduces the safety risks caused by leakage of superheated water. In addition, during the circulation process, due to the reduction in the amount of heated water, some high-temperature steam is also saved, thereby achieving energy and water conservation.

[0006] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical solutions:

[0007] A continuous sterilization method without a superheated water tank comprises the following steps:

[0008] Water filling step: the water in the clean water tank is transported to the continuous disinfection system, and finally flows back to the clean water tank to form a closed loop. The continuous disinfection system includes a cold side channel of the preheating heat exchanger, a heater, a maintainer and a hot side channel of the preheating heat exchanger which are sequentially connected by pipelines. After the water fills the continuous disinfection system, the valve between the hot side channel of the preheating heat exchanger and the clean water tank is closed;

[0009] Water disinfection circulation step: open the water disinfection circulation valve, control the water inside the continuous disinfection system to circulate through the circulation pump, and use the pressure-stabilizing pump to control the pressure at the inlet of the circulation pump to be constant and greater than the saturated vapor pressure of water at the water disinfection temperature. The water disinfection temperature is 121°C to 140°C. During the circulation process, the heater heats the water to the water disinfection temperature to sterilize the continuous disinfection system;

[0010] Medium sterilization step: transporting the medium to the continuous sterilization system for heating and sterilization, and then transporting the sterilized medium to a sterilized fermentation tank;

[0011] Water top-up step: using the water in the clean water tank to push the culture medium in the continuous disinfection system and pipeline into the sterilized fermentation tank. This step is also the process of constant volume of the sterilized fermentation tank.

[0012] Table of relationship between temperature, saturated vapor pressure and gauge pressure of water

[0013]

[0014]

[0015] Compared with the prior art, the continuous sterilization method of the present invention has at least the following beneficial effects:

[0016] In the continuous sterilization method provided by the present invention, in the water disinfection circulation step, the water inside the continuous disinfection system is controlled by a circulation pump to form a circulation, and the pressure at the inlet of the circulation pump is controlled by a pressure-stabilizing pump to be constant and greater than the saturated vapor pressure of water at the water disinfection temperature, thereby ensuring the pressure stability of the water disinfection process and avoiding cavitation of the circulation pump. The method eliminates the superheated water tank and its attached instruments and meters, saves investment costs, and reduces safety risks caused by superheated water leakage. In addition, during the water disinfection circulation process, the amount of heated water is reduced, and part of the high-temperature steam is also saved, achieving energy and water conservation, which will bring good economic benefits to the enterprise.

[0017] In one embodiment, in the water disinfection circulation step, after the water passes through the hot side channel outlet of the preheating heat exchanger, it is transported to the second pipe through the first pipe and re-enters the continuous disinfection system to form a water circulation loop. The second pipe is a part of the pipe in the continuous disinfection system. The first pipe, the second pipe, the main components of the continuous disinfection system (preheating heat exchanger, heater and maintainer) and the connecting pipes between the components together constitute a water circulation loop, and a circulation pump is placed in the water circulation loop to control the superheated water in the water circulation loop for circulation sterilization. The superheated water mentioned here refers to water that remains in a liquid state when it reaches the water disinfection temperature. In this circulation process, the superheated water tank is eliminated, and only the water in the water circulation loop needs to be heated. The amount of water heated is greatly reduced, which reduces heat consumption, and also saves some high-temperature steam and heat energy.

[0018] In one of the embodiments, in the water elimination circulation step, after the water elimination circulation valve is opened, water is transported to the cold side channel of the preheating heat exchanger for preheating under the action of the circulation pump, and then the preheated water is transported to the heater to be heated to the water elimination temperature, and enters the hot side channel of the preheating heat exchanger through the maintainer to exchange heat with the water in the cold side channel of the preheating heat exchanger. The water after the heat exchange enters the connection between the first pipe and the second pipe through the first pipe, and then is transported to the second pipe for circulation until the water temperature in the entire water circulation loop reaches the water elimination temperature, and the water elimination circulation is continued for 5 minutes to 30 minutes.

[0019] In one of the embodiments, in the water elimination circulation step, the water in the clean water tank is dynamically replenished into the water circulation loop through the pressure-stabilizing pump.

[0020] In this continuous sterilization process, multiple drainage pipes are provided. When the equipment is shut down for a long time, the water in the equipment needs to be drained through the drainage pipes. During the water disinfection process, when sterilizing the pipes, in order to achieve a good sterilization effect, the valves on the drainage pipes need to be opened and closed multiple times to ensure that the pipes are filled with superheated water. During this period, some water will be discharged from the pipes, and the pressure in the water circulation loop will fluctuate. The pressure-stabilizing pump needs to be used to dynamically replenish the water in the clean water tank into the water circulation loop to ensure constant pressure and avoid vaporization of superheated water in the water circulation loop, which will cause cavitation to the circulation pump.

[0021] In one embodiment, the pressure-stabilizing pump is a variable frequency pump, which controls the pressure at the inlet of the circulation pump to be constant by changing the frequency; the pressure-stabilizing pump can also be an industrial frequency pump, and the pressure output by the industrial frequency pump is greater than the saturated vapor pressure of water at the water disinfection temperature.

[0022] In the traditional continuous sterilization process, when the continuous sterilization system itself is sterilized, a superheated water tank is usually used as a pressure vessel for water sterilization. In the embodiment of the present application, the superheated water tank is eliminated, and a pressure-stabilizing pump is used to increase the pressure of the water circulation loop. On the one hand, since the superheated water tank and its attached instruments and meters are eliminated, the investment cost is saved and the safety risk caused by the leakage of superheated water is reduced; on the other hand, after the continuous sterilization system itself is sterilized, when the culture medium is sterilized, the pressure in the feed pipeline will fluctuate greatly at the moment of valve switching, and the superheated water will vaporize, causing the superheated water to enter the pump in the form of saturated steam, causing cavitation of the pump, damage to the pump, and even causing personal injury. The pressure-stabilizing pump in the embodiment of the present application can be a variable frequency pump, which is interlocked with the pressure gauge at the inlet of the circulation pump, and the pressure at the inlet of the circulation pump is controlled to be constant by frequency change, so as to ensure that the pressure at the inlet of the circulation pump is greater than the saturated vapor pressure of water at the water disinfection temperature; the pressure-stabilizing pump can also be a power frequency pump, and a flow regulating valve is provided between the pressure-stabilizing pump and the pressure gauge at the inlet of the circulation pump, and the flow regulating valve is interlocked with the pressure gauge at the inlet of the circulation pump, and the pressure at the inlet of the circulation pump is made greater than the saturated vapor pressure of water at the water disinfection temperature by adjusting the opening of the flow regulating valve. In this way, the pressure of the continuous sterilization process is ensured to be stable during the water disinfection operation, and cavitation of the circulation pump can be avoided, which may cause equipment failure.

[0023] In one embodiment, the number of the circulation pumps is at least one. When a plurality of the circulation pumps are used, the plurality of circulation pumps are connected in series.

[0024] In the embodiment of the present application, the water is controlled to flow in the water circulation loop by a circulation pump to achieve a sterilization effect. The number of circulation pumps can be 1, 2, etc., and there is no limitation on this, as long as the water can be circulated and the sterilization effect can be achieved.

[0025] It should be noted that if there are multiple circulating pumps and the pressure-stabilizing pump is a variable frequency pump, then the pressure-stabilizing pump and the pressure gauge at the inlet of the first circulating pump are interlocked to control the pressure at the inlet of the first circulating pump to be constant and greater than the saturated vapor pressure of water at the water disinfection temperature; the pressure gauges at the inlet of the first circulating pump and the second circulating pump are interlocked to control the pressure at the inlet of the second circulating pump to be constant and greater than the saturated vapor pressure of water at the water disinfection temperature; and so on, it is necessary to ensure that each pump does not cavitate.

[0026] In other embodiments, the pressure-stabilizing pump can also be an industrial frequency pump. A flow regulating valve is provided between the pressure-stabilizing pump and the pressure gauge at the inlet of the first circulating pump. The flow regulating valve is interlocked with the pressure gauge at the inlet of the first circulating pump. By adjusting the opening of the flow regulating valve, the pressure at the inlet of the first circulating pump is made greater than the saturated vapor pressure of water at the water disinfection temperature, and so on, to ensure that each pump does not cavitate.

[0027] In the above two cases, the circulating pump can be a variable frequency pump, and the pressure of the subsequent circulating pump can be controlled by frequency change. Of course, the circulating pump can also be a power frequency pump. In this case, a flow regulating valve is provided between the pressure gauges at the inlet of the first circulating pump and the second circulating pump. By adjusting the opening of the flow regulating valve, the pressure at the inlet of the first circulating pump is greater than the saturated vapor pressure of water at the water temperature, and so on, to ensure that each pump does not cavitation.

[0028] In one embodiment, in the water disinfection circulation step, the water disinfection temperature is 125°C to 140°C, and after the water temperature reaches the water disinfection temperature, the water disinfection circulation is performed for 5 minutes to 15 minutes.

[0029] Generally speaking, the higher the sterilization temperature, the shorter the sterilization time required. However, if the sterilization temperature is too high, the requirements for high-temperature steam will be more stringent, which will increase the cost of the enterprise, and the economic and environmental benefits will be greatly affected. Therefore, it is necessary to ensure that the process not only meets certain sterilization requirements, but also ensures that energy is easily available and easy to control. Taking all factors into consideration, the water disinfection temperature of the water disinfection cycle is preferably 125℃~140℃. After the water temperature reaches the water disinfection temperature, the water disinfection cycle is 5min~15min.

[0030] In one of the embodiments, in the water elimination circulation step, the water in the heater is heated to the water elimination temperature by high temperature steam, and the temperature of the high temperature steam is at least 5° C. higher than the water elimination temperature.

[0031] High-temperature steam enters the heater through the steam pipe, and heats the water preheated by the preheating heat exchanger to the water quenching temperature. The temperature of high-temperature steam must be at least 5°C higher than the water quenching temperature to make the water reach the water quenching temperature. Preferably, the temperature of high-temperature steam is 5°C to 10°C higher than the water quenching temperature, which can not only make the water reach the water quenching temperature faster, but also avoid the situation where the high-temperature steam temperature is too high and difficult to obtain. High-temperature steam generally uses steam from industrial plants.

[0032] In one embodiment, the culture medium sterilization step specifically includes: transporting the culture medium to the cold side channel of the preheating heat exchanger for preheating, the temperature of the preheated culture medium is 115°C to 130°C, and then transporting the preheated culture medium to the heater to be heated to 130°C to 145°C, and after maintaining a certain sterilization time in the maintainer, entering the hot side channel of the preheating heat exchanger to exchange heat with the unsterilized culture medium in the cold side channel of the preheating heat exchanger, and the sterilized culture medium after the heat exchange is transported to the sterilized fermentation tank.

[0033] In one embodiment, the water topping step specifically includes: conveying the water in the clean water tank to the cold side channel of the preheating heat exchanger for preheating, the temperature of the preheated water is 115°C to 130°C, and then conveying the preheated water to the heater to be heated to 130°C to 145°C, and after maintaining a certain sterilization time in the maintainer, entering the hot side channel of the preheating heat exchanger to exchange heat with the unsterilized water in the cold side channel of the preheating heat exchanger, and the water after heat exchange is conveyed to the sterilized fermentation tank; at the same time, the water topping step is also the volume fixing process of the sterilized fermentation tank.

[0034] During the culture medium sterilization and water topping process, the preheating heat exchanger preheats the culture medium / water in the cold side channel, and the hot side channel exchanges heat with the culture medium / water in the cold side channel, so that the waste heat of the heat medium in the hot side channel can be almost completely recovered, and the temperature of the culture medium / water to be heated in the cold side channel can be greatly increased, which is slightly different from sterilization, and can greatly save the use of high-temperature steam.

[0035] In the continuous sterilization process, superheated water is first used to sterilize the continuous sterilization system itself in the water sterilization circulation step. After the sterilization requirements are met, the culture medium is sterilized, and then the culture medium is pushed out with water. When sterilizing the culture medium, under normal circumstances, the higher the sterilization temperature, the shorter the required sterilization time will be. The present invention does not impose specific restrictions on the sterilization temperature and time, as long as the sterilization effect is achieved. Preferably, the temperature of the culture medium after preheating by the preheating heat exchanger is 115°C to 130°C, and the sterilization temperature of the heater is set to 130°C to 145°C. It can not only ensure the sterilization effect, but also achieve better economic and environmental benefits. Similarly, in the water topping process, the water temperature after preheating by the preheating heat exchanger is set to 115°C to 130°C, and the heating temperature of the heater is set to 130°C to 145°C. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 : The process flow of the continuous sterilization method of the non-superheated water tank provided by one embodiment of the present invention Figure 1 ;

[0037] Figure 2 : Another embodiment of the present invention provides a process flow of a continuous sterilization method for a non-superheated water tank Figure 2 ;

[0038] Figure 3 : Another embodiment of the present invention provides a process flow of a continuous sterilization method for a non-superheated water tank Figure 3 ;

[0039] Figure 4 : Another embodiment of the present invention provides a process flow of a continuous sterilization method for a non-superheated water tank Figure 4 ;

[0040] In the figure, 1, clean water tank; 2, pressure-stabilizing pump; 3, preheating heat exchanger; 4, circulation pump; 4.1, first circulation pump; 4.2, second circulation pump; 5, heater; 6, maintainer; 7, water elimination circulation valve; 8, raw material tank; 9, CIP tank DETAILED DESCRIPTION

[0041] The present invention is further described below in conjunction with specific embodiments. It should be noted that the following embodiments are only used to illustrate the present invention rather than to limit the technical solutions described in the present invention, and all technical solutions and improvements that do not depart from the present invention should be included in the scope of the claims of the present invention.

[0042] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the invention, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined. In the description of the present invention, the meaning of "several" is at least one, such as one, two, etc., unless otherwise clearly and specifically defined.

[0043] The words "preferably", "more preferably", etc. in the present invention refer to embodiments of the present invention that may provide certain beneficial effects in certain circumstances. However, other embodiments may also be preferred under the same circumstances or other circumstances. In addition, the description of one or more preferred embodiments does not imply that other embodiments are not applicable, nor is it intended to exclude other embodiments from the scope of the present invention.

[0044] When a numerical range is disclosed herein, the above range is considered to be continuous and includes the minimum and maximum values ​​of the range, as well as every value between such minimum and maximum values. Further, when a range refers to an integer, every integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be combined. In other words, unless otherwise indicated, all ranges disclosed herein should be understood to include any and all subranges included therein.

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0046] In the present invention, "before" and "after" are defined according to the direction of water and culture medium in the process.

[0047] The continuous sterilization method without a superheated water tank disclosed in the present invention can be applied to a continuous sterilization system for sterilizing a culture medium in the microbial fermentation industry on the one hand; on the other hand, it can also be used in an inactivation device containing active wastewater to sterilize the inactivation device.

[0048] Please refer to Figures 1 to 4 , the arrows in the figure indicate the direction of water disinfection circulation, sterilization, and CIP online cleaning. The continuous sterilization method of the non-superheated water tank provided by the present invention is now explained.

[0049] Figure 1 A process flow chart of an embodiment of the present invention is shown in FIG. Figure 1 As shown, the continuous sterilization method of the non-superheated water tank specifically comprises the following steps:

[0050] (1) Water filling step: open the valve at the bottom of the clean water tank 1 and the valve between the hot side channel of the preheating heat exchanger 3 and the clean water tank 1, use the pressure regulating pump 2 and the circulation pump 4 to sequentially transport the water in the clean water tank 1 to the cold side channel of the preheating heat exchanger 3, the heater 5, the maintainer 6, and the hot side channel of the preheating heat exchanger 3, and finally return to the clean water tank 1 to form a closed loop. After the water fills all components and pipes, close the valve between the hot side channel of the preheating heat exchanger 3 and the clean water tank 1;

[0051] (2) Water disinfection circulation step: open the water disinfection circulation valve 7, and under the action of the circulation pump 4, transport water to the cold side channel of the preheating heat exchanger 3 for preheating, and then transport the preheated water to the heater 5 to be heated to a water disinfection temperature of 121°C to 140°C. After the water disinfection temperature is maintained in the maintainer 6 for a period of time, the water enters the hot side channel of the preheating heat exchanger 3 to exchange heat with the water in the cold side channel of the preheating heat exchanger 3. The hot water after the heat exchange is completed enters the connection between the first pipeline and the second pipeline (i.e. Figure 1 The water is then transported to the second pipeline, re-enters the cold side channel of the preheating heat exchanger 3, and performs a water elimination cycle. From point A, it goes to the cold side channel of the preheating heat exchanger 3, the circulation pump 4, the heater 5, the maintainer 6, the hot side channel of the preheating heat exchanger 3, the water elimination circulation valve 7, and finally returns to point A to form a water circulation loop, until the water temperature in the entire water circulation loop reaches the water elimination temperature, and the water elimination cycle continues for 5 minutes to 30 minutes. During the water elimination cycle, the high-temperature steam enters the heater 5 through the steam pipe, and the preheated water is heated to 121°C to 140°C in the heater 5. The temperature of the high-temperature steam is at least 5°C higher than the water elimination temperature.

[0052] In the water disinfection circulation step, when the pressure-stabilizing pump 2 is a variable frequency pump, the frequency of the pressure-stabilizing pump 2 is changed, and when the pressure-stabilizing pump 2 is an industrial frequency pump, the opening of the flow regulating valve is adjusted to control the pressure at the inlet of the circulation pump 4 to be constant, ensuring that the pressure at the inlet of the circulation pump 4 is greater than the saturated vapor pressure of water at the water disinfection temperature. In this way, the pressure stability during the water disinfection circulation process is guaranteed, and the vaporization of superheated water can be avoided, and cavitation of the circulation pump 4 can be generated, causing equipment failure.

[0053] In addition, all components and pipes need to be sterilized. When sterilizing the sewage and exhaust pipes, in order to achieve a good sterilization effect, it is necessary to open and close the valves several times to fill the pipes with superheated water, during which some water will be discharged from the pipes. Figure 1 Point A in the figure is set as a three-way direct connection, and a pressure tank can also be used as a mixing device. The water circulation loop is replenished in time by the pressure-stabilizing pump 2 to ensure that the pressure of the water circulation process is constant. Of course, other mixing devices can also be used at the connection between the first pipeline and the second pipeline, all of which are within the scope of protection of this patent.

[0054] (3) Culture medium sterilization step: open the valve at the bottom of the raw material tank 8, close the water disinfection circulation valve 7, open the valve between the hot side channel of the preheating heat exchanger 3 and the fermentation tank, and close the valve at the bottom of the clean water tank 1. The culture medium in the raw material tank 8 is transported to the cold side channel of the preheating heat exchanger 3 by the pressure regulating pump 2 for preheating. The preheated culture medium temperature is 115°C to 130°C, and then transported to the heater 5 by the circulation pump 4 to be heated to 130°C to 145°C. After being maintained in the maintainer 6 for a certain sterilization time, the culture medium enters the hot side channel of the preheating heat exchanger 3 to exchange heat with the unsterilized culture medium in the cold side channel of the preheating heat exchanger 3. After the heat exchange is completed, the sterilized culture medium is discharged and transported to the sterilized fermentation tank.

[0055] (4) Water top-loading step: open the valve at the bottom of the clean water tank 1, close the valve at the bottom of the raw material tank 8, and transport the water in the clean water tank 1 to the cold side channel of the preheating heat exchanger 3 through the pressure-stabilizing pump 2 for preheating. The preheated water temperature is 115°C to 130°C, and then transport the preheated water to the heater 5 to be heated to 130°C to 145°C. After being maintained in the maintainer 6 for a certain sterilization time, the water enters the hot side channel of the preheating heat exchanger 3 to exchange heat with the unsterilized water in the cold side channel of the preheating heat exchanger 3. The water after heat exchange is transported to the sterilized fermentation tank. This process is also the fermentation tank constant volume process.

[0056] Figure 2 A process flow chart of another embodiment of the present invention is shown in FIG. Figure 2 As shown, the continuous sterilization method of the non-superheated water tank specifically comprises the following steps:

[0057] (1) Water filling step: The operation process of this step is the same as Figure 1 The water filling steps in the embodiment are the same, please refer to Figure 1 The corresponding description in the embodiments;

[0058] (2) Water disinfection circulation step: open the water disinfection circulation valve 7, and under the action of the circulation pump 4, transport water to the cold side channel of the preheating heat exchanger 3 for preheating, and then transport the preheated water to the heater 5 to be heated to a water disinfection temperature of 121°C to 140°C. After the water disinfection temperature is maintained in the maintainer 6 for a period of time, the water enters the hot side channel of the preheating heat exchanger 3 to exchange heat with the water in the cold side channel of the preheating heat exchanger 3. The hot water after the heat exchange is completed enters the connection between the first pipeline and the second pipeline (i.e. Figure 2 The water is then transported to the second pipeline and re-enters the heater 5 for water disinfection circulation. From point A, it goes to the circulation pump 4, the heater 5, the maintainer 6, the hot side channel of the preheating heat exchanger 3, the water disinfection circulation valve 7 and finally returns to point A to form a water circulation loop. The water temperature in the entire water circulation loop reaches the water disinfection temperature, and the water disinfection circulation cycle continues for 5 minutes to 30 minutes. The cold side channel of the preheating heat exchanger 3 is heated to the water disinfection temperature by the hot water in the hot side channel to achieve disinfection and sterilization. During the water disinfection circulation process, high-temperature steam enters the heater 5 through the steam pipe, and the preheated water is heated to 121°C to 140°C in the heater 5. The temperature of the high-temperature steam is at least 5°C higher than the water disinfection temperature.

[0059] (3) Culture medium sterilization step: The operation process of this step is similar to Figure 1 The sterilization steps of the culture medium in the examples are the same, please refer to Figure 1 The corresponding description in the embodiments;

[0060] (4) Water top material step: The operation process of this step is the same as Figure 1 The water top material steps in the embodiment are the same, please refer to Figure 1 The corresponding description in the embodiments.

[0061] Figure 3 A process flow chart of another embodiment of the present invention is shown in FIG. Figure 3 As shown, the process uses two circulation pumps for water circulation. The continuous sterilization method without superheated water tank specifically includes the following steps:

[0062] (1) Water filling step: open the valve at the bottom of the clean water tank 1 and the valve between the hot side channel of the preheating heat exchanger 3 and the clean water tank 1, and use the first circulation pump 4.1 and the second circulation pump 4.2 to sequentially transport the water in the clean water tank 1 to the cold side channel of the preheating heat exchanger 3, the heater 5, the maintainer 6, and the hot side channel of the preheating heat exchanger 3, and finally return to the clean water tank 1 to form a closed loop. After the water fills all components and pipes, close the valve between the hot side channel of the preheating heat exchanger 3 and the clean water tank 1;

[0063] (2) Water disinfection circulation step: open the water disinfection circulation valve 7, the valve between the bottom of the clean water tank 1 and the pressure-stabilizing pump 2, and the pressure-stabilizing pump 2, and close the valve at the bottom of the clean water tank 1. Under the action of the first circulation pump 4.1 and the second circulation pump 4.2, water is transported to the cold side channel of the preheating heat exchanger 3 for preheating, and then the preheated water is transported to the heater 5 and heated to the water disinfection temperature of 121°C to 140°C. After the water disinfection temperature is maintained in the maintainer 6 for a period of time, it enters the hot side channel of the preheating heat exchanger 3 and exchanges heat with the water in the cold side channel of the preheating heat exchanger 3. The hot water after the heat exchange is completed enters the connection between the first pipeline and the second pipeline (i.e. Figure 3 The water is then transported to the second pipeline, re-enters the cold side channel of the preheating heat exchanger 3, and performs a water elimination cycle. From point A, it goes to the first circulation pump 4.1, the cold side channel of the preheating heat exchanger 3, the second circulation pump 4.2, the heater 5, the maintainer 6, the hot side channel of the preheating heat exchanger 3, the water elimination circulation valve 7, and finally returns to point A to form a water circulation loop, until the water temperature in the entire water circulation loop reaches the water elimination temperature, and the water elimination cycle continues for 5 minutes to 30 minutes. During the water elimination cycle, the high-temperature steam enters the heater 5 through the steam pipe, and the preheated water is heated to 121°C to 140°C in the heater 5. The temperature of the high-temperature steam is at least 5°C higher than the water elimination temperature.

[0064] In the water disinfection circulation step, the pressure at the inlet of the first circulation pump 4.1 is controlled to be constant by changing the frequency of the pressure-stabilizing pump 2 or by adjusting the opening of the flow control valve to ensure that the pressure at the inlet of the first circulation pump 4.1 is greater than the saturated vapor pressure of water at the water disinfection temperature. The circulation pump 4 can be a variable frequency pump, and the pressure gauges at the inlets of the first circulation pump 4.1 and the second circulation pump 4.2 are interlocked. The first circulation pump 4.1 controls the pressure at the inlet of the second circulation pump 4.2 to be constant by changing the frequency, and the pressure is greater than the saturated vapor pressure of water at the water disinfection temperature. Of course, the number of circulation pumps 4 can also be 3, 4, etc., and there is no restriction on this, as long as the water can be circulated to achieve the sterilization effect. When there are multiple circulation pumps 4, the previous circulation pump 4 controls the pressure of the subsequent circulation pump 4 to be constant by changing the frequency to ensure that each pump does not cavitate.

[0065] The circulation pump 4 can also be a power frequency pump. In this case, a flow regulating valve is provided between the pressure gauges at the inlet of the first circulation pump 4.1 and the second circulation pump 4.2. By adjusting the opening of the flow regulating valve, the pressure at the inlet of the first circulation pump 4.1 is made greater than the saturated vapor pressure of water at the water temperature. By analogy, each pump is ensured to be free of cavitation.

[0066] The pressure-stabilizing pump 2 and the circulating pump 4 are both common pumps in the art, such as centrifugal pumps, rotor pumps, gear pumps, screw pumps, etc., and there is no limitation on this. In addition, the pump parameters are not fixed and are set and adjusted according to the actual processing volume and use environment of the water disinfection system. Specifically, at 30m 3 / h water elimination process, the parameters of the pressure-stabilizing pump 2 and the circulation pump 4 are as follows: Pressure-stabilizing pump 2: head 40m, flow 20m 3 / h, first circulation pump 4.1: head 40m, flow 40m 3 / h, second circulation pump 4.2: head 40m, flow 40m 3 / h can meet the demand and has high sterilization efficiency.

[0067] (3) Culture medium sterilization step: open the valve at the bottom of the raw material tank 8, close the water disinfection circulation valve 7, and open the valve between the hot side channel of the preheating heat exchanger 3 and the fermentation tank, and close the valve between the bottom of the clean water tank 1 and the pressure regulating pump 2 and the pressure regulating pump 2. The culture medium in the raw material tank 8 is transported to the cold side channel of the preheating heat exchanger 3 through the first circulation pump 4.1 for preheating. The temperature of the preheated culture medium is 115°C to 130°C, and then the preheated culture medium is transported to the heater 5 through the second circulation pump 4.2 and heated to 130°C to 145°C. After being maintained in the maintainer 6 for a certain sterilization time, the culture medium enters the hot side channel of the preheating heat exchanger 3 to exchange heat with the unsterilized culture medium in the cold side channel of the preheating heat exchanger 3. The sterilized culture medium after heat exchange is discharged and transported to the sterilized fermentation tank.

[0068] (4) Water top-loading step: open the valve at the bottom of the clean water tank 1, close the valve at the bottom of the raw material tank 8, and transport the water in the clean water tank 1 to the cold side channel of the preheating heat exchanger 3 through the first circulation pump 4.1 for preheating. The preheated water temperature is 115℃~130℃, and then the preheated water is transported to the heater 5 through the second circulation pump 4.2 and heated to 130℃~145℃. After being maintained in the maintainer 6 for a certain sterilization time, it enters the hot side channel of the preheating heat exchanger 3 and exchanges heat with the unsterilized water in the cold side channel of the preheating heat exchanger 3. The water after heat exchange is transported to the sterilized fermentation tank. This process is also the fermentation tank constant volume process.

[0069] Figure 4 A process flow chart of another embodiment of the present invention is shown in FIG. Figure 4 As shown, this process is Figure 3 The embodiments are basically the same, the only difference is that Figure 4 In the embodiment, a circulating pump is used for water circulation. The specific steps of the continuous sterilization method without superheated water tank can be referred to Figure 3 The corresponding description in the embodiments.

[0070] In the embodiment of the present invention, after the continuous disinfection system has been running for a certain period of time, it needs to be regularly CIP online cleaned, that is, the cleaning liquid in the CIP tank 9 is passed into the continuous disinfection system for cleaning, and finally the cleaning liquid is pushed out with the water in the clean water tank 1 to achieve the cleaning effect.

[0071] The continuous sterilization method provided by the present invention eliminates the superheated water tank and its attached instruments and meters, thus saving investment costs. The superheated water tank is a pressure vessel, and the equipment itself has high manufacturing requirements, and the cost is about 21,000 to 40,000 yuan. Usually, in order to ensure the safety of the superheated water tank body, it is necessary to install instruments for detecting temperature, pressure, and liquid level and corresponding control valves on the superheated water tank, and the cost of components such as pressure gauges, thermometers, liquid level gauges, and switch valves is about 15,000 to 23,000 yuan. The present invention eliminates the superheated water tank and its instruments and other equipment, which can reduce the cost by about 36,000 to 63,000 yuan, greatly reducing the investment cost of the enterprise, and also reducing the safety risks caused by superheated water leakage.

[0072] In addition, during the circulation process, the amount of water heated is reduced, which also saves some steam, thus saving energy and water. The following is the calculation process of the steam cost saving during the whole life cycle of the equipment.

[0073] Steam saving calculation (based on 2m 3 Take the superheated water tank as an example):

[0074] The water volume of the water elimination circulation process with the hot water tank is 2m more than that of the water elimination circulation process without the hot water tank in the present invention. 3 (Volume of water in the superheated water tank), the mass of the excess water M1 = 2000kg;

[0075] The initial water temperature is calculated as T1 = 25°C; the water elimination temperature is calculated as T2 = 130°C;

[0076] The specific heat capacity of water is C1 = 4.2 kJ / (kg·℃);

[0077] Steam is calculated based on 0.45MPa, and the latent heat of vaporization of steam is C2 = 2095.9kJ / kg;

[0078] Because the water elimination cycle in the overheated water tank requires more steam to heat the excess water M1, the heat Q consumed is:

[0079] Q=C1×(T2-T1)×M1=4.2kJ / (kg·℃)×(130-25)℃×2000kg=882000kJ;

[0080] The amount of steam M2 consumed in a water disinfection cycle is:

[0081] M2 = Q / C2 = 882000 kJ ÷ 2095.9 kJ / kg = 420.82 kg; M2 is also the amount of steam saved by the one-time water disinfection cycle of the embodiment of the present invention;

[0082] The amount of steam M3 saved by sterilizing the culture medium twice a day and performing two water disinfection cycles is:

[0083] M3 = M2 × 2 = 420.82 kg × 2 batches / day = 841.64 kg / day;

[0084] The equipment operation time is calculated as 300 days a year, and the amount of steam M4 saved in a year is:

[0085] M4 = M3 × 300 = 252492 kg / year = 252.492 tons / year;

[0086] The equipment service life is calculated as 10 years, and the amount of steam M5 saved during the entire life cycle of the equipment is:

[0087] M5 = 252.492 tons / year × 10 years = 2524.92 tons;

[0088] The steam price is calculated as S = 260 yuan / ton, and the steam cost Y saved during the entire life cycle of the equipment is:

[0089] Y = 2524.92 tons × 260 yuan / ton = 656479.2 yuan = 656,500 yuan.

[0090] Since the volume of hot water tanks used in continuous elimination systems with different flow rates is different, the steam cost saved during the entire life cycle of the equipment after calculation according to the above calculation method is shown in the following table:

[0091] Serial number Device Model <![CDATA[M1(kg)]]> <![CDATA[M2(kg)]]> <![CDATA[M3 (kg / day)]]> <![CDATA[M4 (tons / year)]]> <![CDATA[M5 (tons)]]> Y (ten thousand yuan) 1 <![CDATA[15m 3 / h]]> 2000 420.82 841.64 252.492 2524.92 65.65 2 <![CDATA[30m 3 / h]]> 2000 420.82 841.64 252.492 2524.92 65.65 3 <![CDATA[50m 3 / h]]> 5000 1052.05 2104.10 631.230 6312.30 164.12 4 <![CDATA[80m 3 / h]]> 5000 1052.05 2104.10 631.230 6312.30 164.12 5 <![CDATA[100m 3 / h]]> 5000 1052.05 2104.10 631.230 6312.30 164.12

[0092] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0093] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions or improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A continuous sterilization method without a superheated water tank, characterized in that: The following steps are involved: Water filling step: the water in the clean water tank is transported to the continuous disinfection system, and finally flows back to the clean water tank to form a closed loop. The continuous disinfection system includes a cold side channel of the preheating heat exchanger, a heater, a maintainer and a hot side channel of the preheating heat exchanger which are sequentially connected by pipelines. After the water fills the continuous disinfection system, the valve between the hot side channel of the preheating heat exchanger and the clean water tank is closed; Water disinfection circulation step: open the water disinfection circulation valve, control the water inside the continuous disinfection system to circulate through the circulation pump, and use the pressure-stabilizing pump to control the pressure at the inlet of the circulation pump to be constant and greater than the saturated vapor pressure of water at the water disinfection temperature. The water disinfection temperature is 121°C to 140°C. During the circulation process, the heater heats the water to the water disinfection temperature to sterilize the continuous disinfection system; Medium sterilization step: transporting the medium to the continuous sterilization system for heating and sterilization, and then transporting the sterilized medium to a sterilized fermentation tank; Water top-up step: using the water in the clean water tank to top-up the culture medium in the continuous disinfection system and the pipeline into the sterilized fermentation tank, and this step is also the process of constant volume of the sterilized fermentation tank; In the water elimination circulation step, after passing through the hot side channel outlet of the preheating heat exchanger, the water is transported to the second pipeline through the first pipeline and re-enters the continuous elimination system to form a water circulation loop.

2. The method for continuous sterilization of a non-superheated water tank according to claim 1, characterized in that: In the water elimination circulation step, after the water elimination circulation valve is opened, water is transported to the cold side channel of the preheating heat exchanger for preheating under the action of the circulation pump, and then the preheated water is transported to the heater to be heated to the water elimination temperature, and enters the hot side channel of the preheating heat exchanger through the maintainer to exchange heat with the water in the cold side channel of the preheating heat exchanger. The water after the heat exchange enters the connection between the first pipe and the second pipe through the first pipe, and then is transported to the second pipe for circulation until the water temperature in the entire water circulation loop reaches the water elimination temperature, and the water elimination circulation is continued for 5 minutes to 30 minutes.

3. The continuous sterilization method of a non-superheated water tank according to claim 1, characterized in that: In the water elimination circulation step, the water in the clean water tank is dynamically replenished into the water circulation loop through the pressure-stabilizing pump.

4. The continuous sterilization method of a non-superheated water tank according to claim 1, characterized in that: The pressure-stabilizing pump is a variable frequency pump, which controls the pressure at the inlet of the circulation pump to be constant by changing the frequency; or, the pressure-stabilizing pump is an industrial frequency pump, and the pressure output by the industrial frequency pump is greater than the saturated vapor pressure of water at the water disinfection temperature.

5. The continuous sterilization method of non-superheated water tank according to claim 1, characterized in that: The number of the circulating pumps is at least one. When a plurality of the circulating pumps are used, the plurality of circulating pumps are connected in series.

6. The method for continuous sterilization of a non-superheated water tank according to claim 2, characterized in that: In the water disinfection circulation step, the water disinfection temperature is 125°C to 140°C. After the water temperature reaches the water disinfection temperature, the water disinfection circulation is performed for 5min to 15min.

7. The method for continuous sterilization of a non-superheated water tank according to claim 1 or 6, characterized in that: In the water elimination circulation step, the water in the heater is heated to the water elimination temperature by high-temperature steam, and the temperature of the high-temperature steam is at least 5° C. higher than the water elimination temperature.

8. The method for continuous sterilization of a non-superheated water tank according to claim 1, characterized in that: The culture medium sterilization step specifically includes: transporting the culture medium to the cold side channel of the preheating heat exchanger for preheating, the temperature of the preheated culture medium is 115°C to 130°C, and then transporting the preheated culture medium to the heater to be heated to 130°C to 145°C, and after maintaining a certain sterilization time in the maintainer, entering the hot side channel of the preheating heat exchanger to exchange heat with the unsterilized culture medium in the cold side channel of the preheating heat exchanger, and the sterilized culture medium after the heat exchange is transported to the sterilized fermentation tank.

9. The method for continuous sterilization of a non-superheated water tank according to claim 1, characterized in that: The water topping step specifically includes: conveying the water in the clean water tank to the cold side channel of the preheating heat exchanger for preheating, the temperature of the preheated water is 115°C to 130°C, and then conveying the preheated water to the heater to be heated to 130°C to 145°C, and after maintaining a certain sterilization time in the maintainer, entering the hot side channel of the preheating heat exchanger to exchange heat with the unsterilized water in the cold side channel of the preheating heat exchanger, and the water after heat exchange is conveyed to the sterilized fermentation tank; at the same time, the water topping step is also the volume fixing process of the sterilized fermentation tank.

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