JPS6099968A - Method of cooling brine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] This invention is an intermediary to the brine cooling method.

In recent years, with the development of the chemical industry, processes in lower temperature ranges have been developed in various fields, and the demand for low temperature generators in lower temperature ranges on an industrial scale has increased.

Generally, a conventional brine cooling method using a refrigerator is applied as a solution to this problem, but it is difficult to obtain the desired low temperature with this method. There are also methods of using cold energy such as direct cooling using liquefied nitrogen, but this method does not result in local freezing (and it is difficult to achieve precise temperature control, and it is also difficult to reuse the vaporized gas). There is also a cost problem.

For example, the applications are wide-ranging, such as the use of cold energy to quickly freeze foods and drugs, or the use of cold energy for low-temperature reactions in the chemical industry.Moreover, the required temperature is increasingly lower, and the accuracy of temperature control is also high. There is a growing desire for something higher.

To explain in more detail about low-temperature processes in each field, in the food and drug industry, a low temperature of -60℃ or less is required for pre-freezing food and drug products. Rapid freezing results in dense frozen particles, which prevents cell destruction of the object to be cooled, improves quality, and shortens freezing time. Furthermore, by lowering the temperature of food and drug freezers to even lower temperatures than current ones, it will be possible to extend shelf life and maintain quality. In addition, it is possible to quickly deal with the large heat load fluctuations (temperature fluctuations) due to frequent loading and unloading, items accompanying the loading and unloading, five people outside, etc. which are characteristic of these features. Furthermore, low-temperature reactions involving fine chemicals, including pharmaceuticals, require ultra-low temperatures of, for example, -60°C or lower.Moreover, since the reaction is mainly a batch reaction, rapid cooling is required at the start of the reaction, resulting in a large amount of water as low as -90°C. It is necessary to remove and cool the reaction heat with low-temperature brine, and then, when the reaction stabilizes, supply brine with high precision at about -90°C ± 2°C to always remove a constant amount of reaction heat. However, at such extremely low temperatures and rapid load fluctuations (
It is very difficult to perform cooling that requires high temperature control accuracy and can sufficiently follow temperature fluctuations, using the above-mentioned conventional brine cooling method and direct cooling method using liquefied nitrogen or the like. Moreover, this is especially true when temperature control of multiple low-temperature reactors is performed simultaneously. Conventionally, methods to obtain ultra-low temperatures include methods using low-temperature brine using mechanical refrigerators such as multi-vapor compression refrigerators, multi-stage generation and multi-stage absorption refrigerators, or using cold energy such as carbon dioxide gas or liquefied nitrogen. Direct methods were used. However, the conventional methods have many problems such as temperature conditions, equipment costs, and difficulty in handling as described below, and the reality is that none of the methods can achieve satisfactory cooling.

In other words, in the conventional brine cooling method, the brine is cooled using a vapor compression refrigerator or an absorption refrigerator.
This cooled brine is used to cool objects to be cooled, but the equipment itself is generally large and has the disadvantage of not being able to follow sudden load fluctuations (?A degree fluctuations). .

To explain in more detail, when obtaining brine at a low temperature of -60°C or less using the vapor compression refrigerator described in (1) above, 2.
A multicomponent refrigeration system using two or more different types of refrigerants is required. The above-mentioned two-way refrigerator is equipped with a low-temperature side refrigerator and a high-temperature side refrigerator, and the condensing part of the low-temperature side refrigerator is cooled by the high-temperature side refrigerator. -22, etc. are used, and R-13, R-14, etc. are used on the low temperature side. However, multicomponent refrigerators such as binary refrigerators are a combination of multiple refrigerators, and stable performance can only be achieved when the operating conditions of these multiple refrigerators match. It is. However, in reality, it is difficult to balance the operating states of multiple refrigerators, and it is extremely difficult to operate them in a well-balanced manner, especially when cooling something with large load fluctuations. be.

Furthermore, such a multicomponent refrigeration system requires a complex system as a whole, which results in extremely high equipment costs and requires a large amount of maintenance costs and personnel.

In addition, in the absorption refrigerator mentioned above, ammonia vapor is absorbed into water at low temperature and low pressure, heated under high pressure to separate ammonia vapor, liquefied in a condenser, passed through an expansion valve, and passed through an evaporator. However, like the above-mentioned multi-component refrigerator, this absorption chiller is a multi-stage generation and multi-stage absorption type, making the entire device complex, increasing equipment costs, and making it difficult to balance the operating conditions. It is extremely difficult to cool down items with large load fluctuations. Furthermore, since the refrigerant used is ammonia, which is toxic and flammable, there is a problem in that extremely careful operation and handling are required.

In this way, conventional brine cooling methods all use multi-stage refrigerators, multi-stage generation, and multi-stage absorption refrigerators, which are difficult to operate and handle, and cannot quickly respond to load fluctuations (temperature fluctuations). It has also been impossible to control the temperature of the brine with high precision. In addition, as another method, carbon dioxide gas,
There is a method of directly cooling the object using cold energy such as liquefied nitrogen, but in the case of cooling with carbon dioxide gas, the cooling temperature is 178°C or higher, and moreover, it is in the state of solid carbonic acid (dry ice). It is extremely inconvenient to handle. On the other hand, in the case of direct cooling with liquefied nitrogen, the temperature of the liquefied nitrogen is extremely low at -196°C, and the temperature difference between the temperature of the object to be cooled is so large that it is extremely difficult to control the temperature of the object to be cooled, and the temperature of the object to be cooled is extremely low. Due to the extremely low temperature of ℃, depending on the cooling method, there is a risk that the object to be cooled may locally freeze, so extreme care must be taken in operating methods and handling. Furthermore, it is virtually impossible to reuse the vaporized ultra-low temperature gas used as a cold source, which is uneconomical.

This invention was made in view of the above circumstances, and includes a brine flow path in which brine can circulate between a brine cooler that cools brine and a cooled object cooling section that cools objects to be cooled. A brine cooling method in which an object to be cooled is cooled by circulating brine, characterized in that an ultra-low temperature fluid is used as a cooling source for the brine, and the brine is cooled by the ultra-low temperature fluid through heat exchange. Its gist is the cooling method.

In other words, this brine cooling method uses ultra-low-temperature fluid as a cooling source for brine and cools the brine with the large amount of cold energy possessed by the ultra-low-temperature fluid, so it can fully meet the demand for low-temperature cooling and is resistant to large load fluctuations (temperature fluctuations). This will enable quick response and precise temperature control. Furthermore, since this method can be realized with simple equipment, the equipment cost is low and operation, handling, maintenance, etc. are easy. Note that the method of the present invention is safe because it does not use highly toxic and flammable materials such as ammonia.

Examples of the ultra-low temperature fluid serving as a cooling source for brine cooling include ultra-low temperature fluids such as liquefied nitrogen, liquefied oxygen, and liquefied argon. However, liquid nitrogen is usually used.

As brine, for example, calcium chloride, ethylene glycol, methylene chloride, etc. are usually used, but these cannot be used as brine at temperatures below -90°C, and if Freon-11 is used as an ultra-low temperature brine, it has a low freezing point ( -111℃), boiling point is high (+23.8℃), non-toxic
It is nonflammable, easy to handle, and is ideal as an ultra-low temperature brine of around -90°C.

Next, the present invention will be explained in detail based on examples.

In other words, this example uses liquefied nitrogen as the ultra-low temperature fluid.
This system uses Freon-11 as the brine to obtain an ultra-low temperature brine of 90±2°C, and effectively utilizes the nitrogen gas vaporized after cooling the brine.

In FIG. 1 showing the configuration of an embodiment of the present invention,
is a brine circulation system, which includes a brine tank 2, a brine circulation pump 3. Brine cooler4. A heat exchanger 5 is provided. 6 is a piping on the high temperature side of the brine circulation system 1, and 7 is a piping on the low temperature side of the brine circulation system 1. 10 is a liquefied nitrogen supply system, which includes a liquefied nitrogen storage tank 11. Liquefied nitrogen evaporator 12
．． Liquefied nitrogen flow control valve 13. Nitrogen gas warmer 1
It is equipped with 4. 15 is a liquefied nitrogen pipe that leads liquefied nitrogen from the liquefied nitrogen storage tank 11 of the liquefied nitrogen supply system 10 to the brine cooler 4; 16 is a vaporized gas outlet pipe that leads the nitrogen gas vaporized in the brine cooler 4; and 17 is an evaporator. This is a nitrogen gas side pipe that sends out nitrogen gas vaporized by 12. The liquefied nitrogen flow rate control valve 13 provided in the liquefied nitrogen pipe 15 detects the temperature of the brine flowing in the low-temperature side pipe 7 of the brine circulation system 1, and controls the temperature indication valve to output a signal so that the brine temperature becomes constant. It is controlled by a meter 18 to automatically increase or decrease the amount of liquefied nitrogen fed into the brine cooler 4. 20 is a nitrogen gas reuse system, pressure regulating valve 21.18 gas chamber 22
and a discharge valve 23. That is, this nitrogen gas reuse system 20 is connected to the gas side piping 1 of the liquefied nitrogen supply system 10.
The vaporized nitrogen gas in the vaporized gas outlet tube 16 is guided into the nitrogen gas chamber 22 after adjusting the gas pressure with the pressure regulating valve 21, and the nitrogen gas in the vaporized gas outlet pipe 16 is also introduced into the nitrogen gas chamber 22 and re-introduced. (In this embodiment, air is sent into the cooled system 24.) The nitrogen gas supplied to the cooled system 24 expels the air in the system to create a nitrogen gas atmosphere, thereby preventing oxidation of the cooled object (not shown) and providing safety such as explosion protection. Incidentally, surplus nitrogen gas outside the mounting plate necessary for reuse or total nitrogen gas when reuse is not necessary is released into the atmosphere from the release valve 23.

In this configuration, cooling of the object to be cooled in the to-be-cooled system 24 is performed as follows. That is, when the apparatus is operated, brine placed in the brine tank 2 is sent to the brine cooler 4 through the high temperature side piping 6 by the action of the pump 3. The brine cooler 4 is supplied with liquefied nitrogen from the liquefied nitrogen storage tank 11 by utilizing the pressure difference to the liquefied nitrogen pipe 1.
5, where the brine and liquefied nitrogen exchange heat, the brine is cooled to a low temperature (-90°C or less), and the liquefied nitrogen is vaporized to become a gas at about -100°C. The cooled brine passes through the low temperature side piping 7 to the cooled system 24.
The brine reaches the heat exchanger 5 in the brine tank 2, where it cools the object to be cooled, and returns to the brine tank 2 at a raised temperature. Then, by the action of the brine circulation pump 3, the brine cooler 4 is again
It exchanges heat with liquefied nitrogen, becomes low temperature, and is sent to heat exchanger 5.
The object to be cooled is cooled. In this way, the brine circulates and the object to be cooled is continuously cooled. In this case, the temperature indicating controller 18 installed in the low temperature side pipe 7 detects the temperature of the brine in the pipe 7 and outputs a signal to keep the temperature constant, and the liquefied nitrogen flow rate control valve 13 By controlling the amount of liquefied nitrogen fed into the brine cooler 4, the temperature of the brine in the low temperature side pipe 7 is kept constant with high precision. In addition, in the brine cooler 4, the liquefied nitrogen that cooled the brine is vaporized and becomes nitrogen gas (-
100°C), enters the nitrogen gas warmer 14 through the vaporized gas outlet pipe 16, is heated to about room temperature, is sent to the nitrogen gas chamber 22, and is released into the atmosphere via release #-23. Alternatively, the air is sent into the cooled system 24 via the piping 25.

When only vaporized nitrogen gas is required, the flow rate control valve 13 of the liquefied nitrogen pipe 15 is closed, and the liquefied nitrogen in the liquefied nitrogen storage tank 11 is sent through the liquefied nitrogen evaporator 12 into the nitrogen gas side pipe 17. is introduced into the nitrogen gas chamber 22 via the pressure regulating valve 21 and taken out from there.

In this way, this embodiment cools the brine using liquefied nitrogen, which has an extremely large amount of cold energy at an ultra-low temperature, so it can fully meet the demands for low-temperature cooling, and can also avoid large load fluctuations (temperature fluctuations) of the object to be cooled. We can also respond quickly and adequately. Furthermore, since the temperature of the brine is controlled by adjusting the amount of liquefied nitrogen fed into the brine cooler 4 using the temperature indicator controller 18 and the flow rate control valve 13, highly accurate temperature control is possible. In addition, since the temperature of the brine is controlled by adjusting the flow rate of liquefied nitrogen, the equipment is significantly simpler than conventional equipment, and its operation, handling, and maintenance are also easier.
Moreover, the equipment cost is also low. Furthermore, the amount of liquefied nitrogen consumed is reasonable and economical. Note that when liquefied nitrogen is vaporized and the nitrogen gas is used for other equipment, the cost can be significantly reduced if the heat of vaporization of liquefied nitrogen is effectively utilized for brine cooling.

In addition, in the above embodiment, the temperature of the brine is controlled by adjusting the flow rate of liquefied nitrogen, but the temperature control of the brine is not limited to the method of adjusting the flow rate of liquefied nitrogen. Depending on the method, brine temperature control may be performed using other methods. Further, in the above embodiment, the heat exchanger 5 is connected to the cooled system 2.
4 to cool the object to be cooled, but instead of using the heat exchanger 5, it is possible to cool the object by pouring brine directly onto the object, or by immersing the object in the brine circuit. You may also do so.

The brine cooling method of this invention cools the brine with an ultra-low temperature fluid that has a large amount of cold energy, and thereby cools the object to be cooled. Therefore, it can sufficiently meet the demand for low-temperature cooling, and also has large load fluctuations (temperature fluctuations) of the object to be cooled. This makes it possible to quickly respond to fluctuations in temperature and achieve precise temperature control. Moreover, the gas vaporized after cooling the brine can be reused. Furthermore, since this method can be realized with simple equipment, equipment costs are low and operation, handling, maintenance, etc. are easy. Furthermore, when controlling the temperature of the brine by adjusting the amount of ultra-low temperature fluid fed based on the temperature of the brine in the brine flow path, it becomes possible to control the brine temperature more precisely. In addition, the consumption of ultra-low temperature fluid is also reasonable and economical. The method of the present invention is safe because highly toxic and flammable materials such as ammonia are not used.

[Brief explanation of drawings]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration diagram of an embodiment of the invention. 2... In the brine flow path 3... Brine circulation pump 4... Brine cooler 5... Heat exchanger (11...
・Liquid nitrogen storage tank 13...Liquid nitrogen flow rate control valve 18...Temperature indicating controller Patent applicant Fujisawa Pharmaceutical Co., Ltd. Daido Sanso Co., Ltd. Agent Patent attorney Yukihiko Nishifuji (15) Procedural amendment (voluntary 1) .Indication of the case 1978 Special Fraud Application No. 07180 2, Name of the invention Brine cooling method 3, Person making the amendment Relationship to the case Patent applicant address Osaka prefecture Osaka r-+i ward road (-guchi no. 3 Names Representative of Fujisawa Pharmaceutical Co., Ltd. Representative Director Tomoyoshibe Fujisawa Address 72 Unagidani Nakano-cho, Minami-ku, Osaka City, Osaka Prefecture 1 Name Representative of Daido Oxygen Co., Ltd. Representative Director Yama Tagawabe Statement 6, 7ili Masaru Contents +11 On page 2, line 4 of the specification, the phrase "relating to brine cooling method" is corrected to "relating to brine cooling method." (2) Page 3 of the specification, line 19, r-90 'C±2℃'
Correct the statement to "-90±2℃". (3) On page 6, line 9 of the specification, the phrase ``Difficult load fluctuations'' is corrected to ``Difficult load fluctuations.'' (4) On page 6, line 15 of the specification, "multi-stage refrigerator" is corrected to "multi-stage refrigerator." (5) On page 7, line 11 of the specification, the phrase "cryogenic gas" is corrected to "cryogenic fluid." (6) On page 8, line 15 of the specification, the phrase ``Liquid nitrogen is used.'' is corrected to ``Liquid nitrogen is used.'' (7) On page 8, line 16 of the specification, the words "for example" should be corrected to "for example." (8) On page 9, line 9 of the specification, the phrase "system used" is corrected to "system used." (9) On page 9, line 12 of the specification, the phrase [In, 1 is brine] should be corrected to ``In, 1 is brine.''that's all

Claims (1)

[Claims] +11 A brine cooler that cools brine and a cooled object cooling section that cools objects to be cooled are connected by a brine flow path so that the brine can circulate, and the objects to be cooled are cooled by circulating the brine. A brine cooling method for cooling η, using an ultra-low temperature fluid as a cooling source for the brine, and cooling the brine by the ultra-low temperature fluid in parentheses is performed by heat exchange. (2) A patent claim in which the cooling of the brine by the ultra-low temperature fluid is controlled by adjusting the amount of the ultra-low temperature fluid fed into the brine cooler so that the brine temperature remains constant. Brine cooling method according to scope 1. (3) Claim 1i2 in which the ultra-low temperature fluid is liquefied nitrogen
UJI 2nd UJI is the brine cooling method described in Section 2. (4) The brine cooling method according to any one of claims 1 to 3, wherein the brine is fluorocarbon.