JP5840938B2 - Heat medium cooling device and operation method of heat medium cooling device - Google Patents

Description

  The present invention relates to a heat medium cooling device and a method for operating the heat medium cooling device.

  In chemical reaction processes such as organic synthesis and crystallization, temperature control with high accuracy is required. For this reason, a double-structured container with an independent tank (jacket) through which the heat medium can flow is used outside the reaction tank, and the temperature-controlled heat medium is circulated through this jacket part, The reaction solution is adjusted to a constant temperature. The heat medium supplied to the reaction tank jacket is cooled by a cooling facility disposed in the heat medium circulation line, and is circulated and supplied to the reaction tank jacket.

  As a cooling facility for cooling a heat medium circulating between a heat load such as a reaction tank or the like, for example, a mechanical cooling facility is disclosed (see Patent Document 1). However, with conventional mechanical cooling equipment, the cooling capacity of the heat medium may not be sufficient depending on the target cooling temperature, and it takes a long time to cool the heat medium from room temperature to a predetermined temperature. There was a problem.

  Also, with a temporary increase in heat load such as in summer, a heat load exceeding the capacity of the refrigerant provided in the mechanical cooling equipment may occur, and the heat medium must be maintained at a predetermined temperature due to insufficient cooling capacity. There was a case that could not be.

  On the other hand, if the cooling capacity of the mechanical cooling equipment is designed in accordance with the peak of the heat load, it becomes an overspec device for the average heat load at a constant temperature, and a large amount of contract power is required. Therefore, there was a problem that the cost increased.

JP 10-318647 A

  The present invention was made in view of the above circumstances, and when a heat load exceeding the cooling capacity of a mechanical cooling facility is applied or when it is necessary to cool the heat medium to a set temperature exceeding the capacity, It is an object of the present invention to provide a heat medium cooling device and a method for operating the heat medium cooling device that can cool the heat medium to a predetermined temperature while suppressing a significant increase in cost.

The invention according to claim 1 is a heat medium cooling device for supplying a heat medium whose temperature is controlled to the heat load device,
A circulation path through which the heat medium circulates;
A main circulation pump for circulating a heat medium in the circulation path;
A first heat exchanger provided on the secondary side of the heat load device of the circulation path, for exchanging heat between the refrigerant and the heat medium;
An intermediate heat medium and a heat medium that are provided in the circulation path between the secondary side of the first heat exchanger and the primary side of the heat load device and have a freezing point lower than the freezing point of the heat medium are heated. A second heat exchanger to be exchanged;
A secondary circulation path through which the intermediate heat medium circulates;
A third heat exchanger provided in the auxiliary circulation path for exchanging heat between the intermediate heat medium and liquefied nitrogen;
And a temperature control means for controlling the temperature of the heat medium supplied to the heat load device to a predetermined temperature.

The invention according to claim 2 is a first bypass path provided in the circulation path so as to connect the primary side and the secondary side of the first heat exchanger;
A second bypass path provided in the circulation path so as to connect the primary side and the secondary side of the second heat exchanger;
The heat medium cooling apparatus according to claim 1, further comprising a heat medium path switching unit.

  The invention according to claim 3 is the heat medium cooling device according to claim 1 or 2, wherein a sub-circulation pump is provided on a primary side of the second heat exchanger of the circulation path. .

The invention according to claim 4 is a buffer tank for accumulating nitrogen gas discharged from the third heat exchanger;
It is a pressure control valve which controls the pressure in the said buffer tank, It is a heat-medium cooling device as described in any one of Claim 1 thru | or 3 characterized by the above-mentioned.

The invention according to claim 5 is an operation method of the heat medium cooling device according to claim 1,
When cooling to the final target temperature of the heat medium, the heat medium path is arranged so as to supply the heat medium to one or both of the first and second heat exchangers according to the final target temperature. It is the operating method of the heat-medium cooling device characterized by selecting.

  According to the heat medium cooling device of the first aspect of the present invention, the first heat for exchanging heat between the refrigerant and the heat medium from the secondary side of the heat load device to the circulation path provided with the temperature control means of the heat medium. Since the heat exchanger is arranged in the order of the second heat exchanger that exchanges heat between the intermediate heat medium having a freezing point lower than the freezing point of the heat medium and the heat medium, the first heat exchanger is provided. The sub-cooling facility provided with the second heat exchanger can be used supplementarily while maximizing the capacity of the main cooling facility. As a sub-cooling facility equipped with a second heat exchanger, a liquefied nitrogen type cooling facility with a relatively small required power and a cooling facility using an intermediate heat medium are selected, thereby suppressing a significant increase in power costs. However, it is possible to cope with a temporary increase in heat load. Therefore, when the heat load exceeding the cooling capacity of the main cooling facility equipped with the first heat exchanger is temporarily applied or when it is necessary to cool the heat medium to a set temperature exceeding the capacity, the power cost is greatly increased. The heating medium can be cooled to a predetermined temperature without being raised to a predetermined temperature. The third heat exchanger has a configuration in which an intermediate heat medium cooled to a predetermined temperature by heat exchange with liquefied nitrogen is supplied to the second heat exchanger, and the heat medium and liquefied nitrogen are There is no direct heat exchange. For this reason, even a heat medium having a relatively high freezing point can be used.

  Further, according to the heat medium cooling device of the second aspect of the present invention, heat exchange is performed between the first refrigerant and the heat medium from the secondary side of the heat load device in the circulation path including the temperature control means of the heat medium. The first heat exchanger is configured to be arranged in the order of the second heat exchanger that exchanges heat between the second refrigerant and the heat medium having higher cooling capacity than the first refrigerant. The sub-cooling facility provided with the second heat exchanger can be used supplementarily while maximizing the capacity of the main cooling facility provided with the heat exchanger. Sub-cooling equipment equipped with a second heat exchanger can be selected with a relatively small required equipment power, so it can cope with a temporary increase in heat load while suppressing a significant increase in power costs. can do. Therefore, when the heat load exceeding the cooling capacity of the main cooling facility equipped with the first heat exchanger is temporarily applied or when it is necessary to cool the heat medium to a set temperature exceeding the capacity, the power cost is greatly increased. The heating medium can be cooled to a predetermined temperature without being raised to a predetermined temperature.

  Furthermore, according to the heat medium cooling device and the operation method of the heat medium cooling device of the present invention, the first bypass path provided so as to bypass the first heat exchanger in the circulation path, and the second heat exchange When the second bypass path provided so as to bypass the heater and the switching means for these heat medium paths are provided, the first and second heat exchangers according to the final target temperature of the heat medium It is possible to configure an optimum circulation path by selecting the heating medium path so as to supply the heating medium to one or both of the above. Therefore, when a heat load exceeding the cooling capacity of the main cooling facility equipped with the first heat exchanger is temporarily applied or when it is necessary to cool the heat medium to a set temperature exceeding the capacity, it is possible to cope with it. it can.

1 is a system diagram showing a heat medium cooling device according to a first embodiment to which the present invention is applied. It is a flowchart which shows the operating method of the heat-medium cooling device which is 1st Embodiment to which this invention is applied. It is a systematic diagram which shows the heat-medium cooling device which is 2nd Embodiment to which this invention is applied.

Hereinafter, a heat medium cooling apparatus according to an embodiment to which the present invention is applied will be described in detail with reference to the drawings.
In addition, in the drawings used in the following description, in order to make the features easy to understand, there are cases where the portions that become the features are enlarged for the sake of convenience, and the dimensional ratios of the respective components are not always the same as the actual ones. Absent.

<First Embodiment>
First, the configuration of the heat medium cooling device 100 according to the first embodiment to which the present invention is applied will be described. FIG. 1 is a system diagram of a first embodiment of the heat medium cooling device of the present invention.

  As shown in FIG. 1, the heat medium cooling apparatus 100 according to the first embodiment of the present invention cools the heat medium after cooling the object to be cooled with a cooling facility and controls the heat medium to a predetermined temperature. Is a device for cooling the object to be cooled again. The heat medium cooling device 100 of this embodiment includes a circulation path through which the heat medium circulates, a low-temperature reaction tank (heat load device) 1 that cools the object to be cooled, and a main circulation pump 2 that circulates the heat medium through the circulation path. And a mechanical refrigerator (mechanical cooling facility) 3 and a liquefied nitrogen refrigerator (liquefied nitrogen cooling facility) 4, and from the secondary side of the low-temperature reaction tank 1 to the circulation path The main circulation pump 2, the mechanical refrigerator 3, and the liquefied nitrogen refrigerator 4 are arranged in this order.

As shown in FIG. 1, the circulation path according to the heat medium cooling device 100 of the present embodiment is configured using paths L1 to L9 including pipes and the like through which the heat medium flows, and the connection point P _1. path L1~L9 in to P ₅ is configured such that an annular passage as a whole is branched or confluent, respectively.

Further, the path L2, L4, L7, L8 and L9 of the secondary side connection point _P 1 to P ₃ which is a branch point, (switching means of the heat medium _passage) off valve V 1 ~V ₅ is each path Is provided to be openable and closable. By appropriately selecting an open state or a closed state for these on-off valves V _{1 to} V ₅ , at least one of the mechanical refrigerator 3 and the liquefied nitrogen refrigerator 4 is used as the heat medium that has passed through the low temperature reaction tank 1. The circulation path can be freely configured so that both can be cooled.

  As the heat medium, for example, an alcohol aqueous solution, alcohol, ethylene glycol, silicone oil, or a fluorine-based heat medium can be used.

  The main circulation pump 2 is provided in the path L1 on the secondary side of the low temperature reaction tank 1. That is, the main circulation pump 2 is arranged on the secondary side of the low-temperature reaction tank 1 in the circulation path, and in front of the mechanical refrigerator 3 that is the main cooling facility. As a result, the heat medium can be circulated in the circulation path, and the influence of the heat load on the main circulation pump can be minimized in the temperature control of the heat medium.

  The mechanical refrigerator (mechanical cooling equipment) 3 is provided on the secondary side (exit side) of the low-temperature reaction tank 1 in the circulation path, and the heat medium after cooling the object to be cooled is set to a predetermined set temperature. This is the main cooling equipment for cooling. The mechanical refrigerator 3 includes a path L2 that is a part of a circulation path, a circulation path L10 that circulates a predetermined refrigerant, and a heat exchanger (first first circuit) that is provided across the path L2 and the circulation path L10. (Heat exchanger) 5.

Path L2, after branching from the path L1 at a connecting point P ₁ in the circulation route, with drawn inside of the mechanical refrigerator 3 is a path that merges with the path L7 at a connection point P _2. A path L2 in the mechanical refrigerator 3 includes a heat exchanger 5, a buffer tank 6 for absorbing volume contraction / expansion of the heat medium due to temperature change, a heater 7 for heating the heat medium, and a mechanical refrigerator. A temperature detector 8 for detecting the temperature of the heating medium immediately before exiting from 3 is provided in this order. Further, the temperature detector 8 is provided with a temperature adjuster 9 that outputs a control signal corresponding to the difference between the temperature detected by the temperature detector 8 and the predetermined set temperature.

  The circulation path L <b> 10 is a circulation path that supplies a predetermined refrigerant whose temperature is controlled to the heat exchanger 5. Here, as the refrigerant, for example, a refrigerant such as chlorofluorocarbon and fluorocarbon can be used. In this circulation path L10, from the secondary side of the heat exchanger 5, a compressor 10 that compresses refrigerant, a heat exchanger 11 that includes a fan 11a for liquefying the refrigerant, and a reserve tank that stores the liquefied refrigerant 12. An expansion valve 13 for evaporating the liquefied refrigerant to generate cold is provided in this order.

  The heat exchanger (first heat exchanger) 5 is provided across the path L2 and the circulation path L10, and exchanges heat between the heat medium in the path L2 and the refrigerant in the circulation path L10. is there. Here, since the vaporized refrigerant serving as a cold source is supplied into the circulation path L10 in the heat exchanger 5, the heat medium in the path L2 can be cooled to a predetermined set temperature.

  The liquefied nitrogen type refrigerator (liquefied nitrogen type cooling facility) 4 is provided between the secondary side of the mechanical refrigerator 3 and the primary side of the low temperature reaction tank 1 in the circulation path, and is a main cooling facility. This is an auxiliary cooling facility that enables the heat medium cooled by the mechanical refrigerator 3 to be cooled to a lower temperature. The liquefied nitrogen type refrigerator 4 includes a circulation path (sub-circulation path) L11 through which an intermediate heat medium that does not freeze even if heat exchange with liquefied nitrogen is circulated, a path L12 for supplying liquefied nitrogen as a refrigerant, and a circulation path The heat exchanger (3rd heat exchanger) 14 provided over L11 and the path | route L12 is comprised roughly.

During the circulation path L11 is a heat exchanger 15 provided in the path L5 being disposed between the connection point P ₄ and P ₅ of the circulation path, the heat exchanger 14 included in the liquid nitrogen refrigerator 4 In this way, the intermediate heat medium is circulated. The intermediate heat medium has a freezing point lower than the freezing point of the heat medium, and does not freeze or close in the heat exchanger 14 even when heat exchange with liquefied nitrogen is performed, such as alcohol, mixed alcohol, silicone oil, fluorine-based heat. Use a medium.

  In this circulation path L11, from the secondary side of the heat exchanger 15, a reserve tank 16 for absorbing the influence of volume shrinkage / expansion of the intermediate heat medium due to temperature change, and the intermediate heat medium are circulated in the circulation path L11. The temperature detector 18 for detecting the temperature of the intermediate heat medium after passing through the circulation pump 17, the heat exchanger 14, and the heat exchanger 14 is provided in this order. Further, the temperature detector 18 is provided with a temperature controller 19 that outputs a control signal corresponding to the difference between the temperature detected by the temperature detector 18 and the predetermined set target temperature of the heat medium. Yes.

  The path L <b> 12 is a path for supplying liquefied nitrogen serving as a cold source to the heat exchanger 14. A liquefied nitrogen control valve 20 and a heat exchanger 14 are provided in this order in the path L12 in the liquefied nitrogen refrigerator 4.

  Further, the path L12 outside the liquefied nitrogen type refrigerator 4 is disposed over the path L12 and the path L13, and after the heat exchanger 14 exchanges heat with the intermediate heat medium (liquefied nitrogen type refrigeration). The nitrogen gas discharged from the machine 4) and other fluids from other cold energy sources (not shown) mutually exchange heat, and the nitrogen gas discharged from the heat exchanger 21 is accumulated. A buffer tank 22 is provided in this order.

  The buffer tank 22 is provided with a path L14 for supplying nitrogen gas in the tank to other users and a path L15 for discharging surplus gas from the tank. The path L15 is provided with a pressure control valve 23 for controlling the pressure in the buffer tank 22.

  The heat exchanger (third heat exchanger) 14 is provided across the circulation path L11 and the path L12, and exchanges heat between the intermediate heat medium in the circulation path L11 and the liquefied nitrogen in the path L12. Is. Here, the set temperature is selected so that the temperature of the intermediate heat medium in the circulation path L11 passing through the heat exchanger 14 is lower than a predetermined set temperature of the heat medium set in the mechanical refrigerator 3. be able to. The set temperature of the intermediate heat medium is preferably set to a temperature at which the heat medium does not freeze when heat exchange with the heat medium in the heat exchanger 15 described later is performed.

  Moreover, as the heat exchanger 14, it is preferable to employ a highly efficient heat exchanger with good responsiveness and a small heat medium capacity. Specifically, for example, a plate fin heat exchanger, a plate heat exchanger, a double tube heat exchanger, or the like can be given. Thus, since the amount of the intermediate heat medium to be circulated in the circulation path L11 can be minimized by adopting a heat exchanger having a high efficiency and a small heat medium capacity as the heat exchanger 14, the response Therefore, the accuracy of temperature control of the heat medium that exchanges heat with the intermediate heat medium can be improved.

  The heat exchanger 15 (second heat exchanger) is between the secondary side of the mechanical refrigerator 3 and the primary side of the low-temperature reaction tank 1 in the circulation path and spans the path L5 and the circulation path L11. The heat medium cooled by the mechanical refrigerator 3 in the path L5 and the intermediate heat medium cooled by heat exchange with the liquefied nitrogen in the circulation path L11 exchange heat with each other. . As the heat exchanger 15, one having a low pressure loss and a small liquid volume of the heat medium and the intermediate heat medium is preferable in terms of responsiveness.

  In this way, the heat medium and the intermediate heat medium are mutually heat-exchanged in the heat exchanger 15 provided in the circulation path, whereby the heat medium and the liquefied nitrogen of the liquefied nitrogen type refrigerator 4 are exchanged via the intermediate heat medium. Indirect heat exchange. Thus, even when a heat medium (for example, ethylene glycol or the like) that freezes when directly exchanging heat with liquefied nitrogen is used, it is possible to quickly reach a predetermined set temperature without freezing the heat medium. it can. Further, the heat medium can be cooled to a set temperature lower than that of the mechanical refrigerator.

  Further, in the heat medium cooling device 100 of the present embodiment, a temperature detector 24 that detects the temperature of the heat medium immediately before being supplied to the low temperature reaction tank 1 is detected in the path L6 on the primary side of the low temperature reaction tank 1. And a temperature controller 25 for outputting the temperature of the heating medium as a control signal. On the other hand, a temperature detector 26 that detects the temperature of the heat medium immediately after passing through the low temperature reaction tank 1 and a temperature that outputs the detected temperature of the heat medium as a control signal to the secondary path L1 of the low temperature reaction tank 1. A regulator 27 is provided.

  Furthermore, temperature controllers (temperature control means) 9, 19, 25, 27 provided in the circulation path constituting the heat medium cooling device 100 of the present embodiment, a temperature control unit (not shown) in the control panel C, and Are electrically connected to each other.

The route constituting the circulation path (first bypass passage) L7 is provided so as to directly connect the connection point P ₂ to the connection point P ₁ as the primary side of the mechanical refrigerator 3 and a secondary side The bypass line bypasses the mechanical refrigerator 3.

Similarly, the path constituting the circulation path (second bypass passage) L9, as directly connected to the connection point P ₅ to a connection point P ₃ as the primary side of the liquid nitrogen refrigerator 4 a secondary side This is a bypass line that bypasses the liquefied nitrogen refrigerator 4.

  An inverter 31 ′ for adjusting the frequency so that the flow rate is constant is connected to the main circulation pump 2 of the path L1 related to the heat medium cooling apparatus 100 of the present embodiment in an electric signal, and the flow rate detector The flow rate is adjusted by a signal converter 28 that converts the flow rate detected at 29 into an electrical flow rate signal and a flow rate regulator 29a that outputs the flow rate signal to the inverter 31 ′ as a control signal. Furthermore, a sub-circulation pump 30 that amplifies the flow rate of the heat medium in the circulation path is provided in one path L8 that joins at the connection point P4 on the primary side of the liquefied nitrogen refrigerator 4.

  In addition, an inverter 31 for adjusting the frequency so that the flow rate detected by the flow rate detector 29 is constant is connected to the auxiliary circulation pump 30 in an electrical signal manner. Furthermore, the inverter 31 and the flow rate control unit (not shown) in the control panel C are electrically connected to each other.

  With such a configuration, even when the pressure loss increases due to an increase in the viscosity of the heat medium when the heat medium is used at a low temperature, the necessary flow rate of the heat medium can be secured in the circulation path, and the heat medium In the cooling control, it is possible to reduce the influence of heat input caused by the auxiliary circulation pump 30.

Moreover, when the capacity is insufficient with only the buffer tank 6 in the mechanical refrigerator 3, it is preferable to provide the reserve tank 32 in the path L3 constituting the circulation path. Further, in the path L2 constituting the circulation path, by not providing the opening and closing valve on the upstream side of the connection point P _2, it can be used a buffer tank 6 mechanical in refrigerator 3 across the circulation path.

Further, a flow path control unit (not shown) may be provided in the control panel C so as to be electrically connected to each of the on-off valves V _{1 to} V ₅ provided in the path constituting the circulation path. Good.

  Next, an operation method of the heat medium cooling device 100 according to the first embodiment configured as described above will be described.

(Single operation of mechanical refrigerator)
In the heat medium cooling device 100 of the present embodiment, when the mechanical refrigerator 3 is operated alone, the on-off valves V ₁ and V ₅ are opened and the on-off valves V _{2 to} V ₄ are closed. As a result, after passing through the paths L1, L2, L3, L9, and L6 from the secondary side of the low temperature reaction tank 1, a circulation path connected to the primary side of the low temperature reaction tank 1 is formed again. In this circulation path, the heat medium circulated by the main circulation pump 2 is cooled in the mechanical refrigerator 3 and then supplied again to the low-temperature reaction tank 1.

  When the mechanical refrigerator is operated alone, the temperature of the heat medium is controlled by a temperature control unit (not shown) in the control panel C. Specifically, first, the deviation between the set temperature of the temperature controller 25 provided on the primary side of the low temperature reaction tank 1 and the current heat medium temperature detected by the temperature detector 24 is calculated. Then, the cooling set temperature to be set in the temperature regulator 9 provided in the path L2 in the mechanical refrigerator 3 is determined by cascade control according to the calculated deviation, and the heat medium detected by the temperature detector 8 The mechanical refrigerator 3 is operated so that the following temperature follows.

(Hybrid operation of mechanical refrigerator and liquefied nitrogen refrigerator)
In the heat medium cooling device 100 of the present embodiment, when the cooling time for cooling the heat medium from room temperature to a predetermined temperature is shortened or a load exceeding the capacity of the mechanical refrigerator 3 occurs, the main cooling facility The hybrid operation is performed using the mechanical refrigerator 3 that is the above and the liquefied nitrogen refrigerator 4 that is the auxiliary cooling facility.

When the hybrid operation is performed, the on-off valves V ₁ and V ₂ are opened and the on-off valves V _{3 to} V ₅ are closed. Thereby, after passing the path | routes L1-L6 from the secondary side of the low temperature reaction tank 1, the circulation path connected to the primary side of the low temperature reaction tank 1 again is formed. In this circulation path, the heat medium circulated by the main circulation pump 2 is cooled to the first target temperature in the mechanical refrigerator 3 and further exchanged with the intermediate heat medium in the heat exchanger 15 to obtain the final target. After being cooled to the temperature, it is supplied again to the low temperature reaction tank 1.

  When performing the hybrid operation, the temperature of the heat medium is controlled by a temperature control unit (not shown) in the control panel C. Specifically, first, the deviation between the set temperature of the temperature controller 25 provided on the primary side of the low temperature reaction tank 1 and the current heat medium temperature detected by the temperature detector 24 is calculated. And the cooling preset temperature (1st target temperature) set to the temperature regulator 9 provided in the path | route L2 in the mechanical refrigerator 3 according to the calculated said deviation is determined by cascade control. However, when the cooling set temperature is lower than the set lower limit temperature of the mechanical refrigerator 3, the set lower limit temperature is set as a set value.

  Next, the cooling set temperature set in the temperature controller 19 provided in the circulation path L11 is also determined by cascade control according to the deviation, and the temperature of the intermediate heat medium detected by the temperature detector 18 follows. Thus, the liquefied nitrogen type refrigerator 4 is operated.

By the way, when the liquefied nitrogen type refrigerator 4 is added to the existing heat medium cooling device having only the mechanical refrigerator 3 to configure the heat medium cooling device 100 of the present embodiment, a path L5 constituting a circulation path. Due to the heat exchanger 15 being installed, the pressure loss of the heat medium circulation system increases, and a predetermined heat medium flow rate may not be ensured in the circulation path. In such a case, to change the configuration of the circulation flow path by opening the on-off valve V ₄ while closing the on-off valve V _2. As a result, the heat medium flows into the path L8, and the flow rate of the heat medium in the circulation path is amplified by the auxiliary circulation pump 30 provided in the path L8.

(Single operation of liquefied nitrogen refrigerator)
In the heat medium cooling device 100 of the present embodiment, when the heat medium is circulated below the usable temperature of the mechanical refrigerator 3, the liquefied nitrogen refrigerator 4 is operated alone.

When the liquefied nitrogen type refrigerator 4 is operated alone, the on-off valves V ₂ and V ₃ are opened and the on-off valves V ₁ , V ₄ and V ₅ are closed. As a result, after passing through the paths L1, L7, L4, L5, and L6 from the secondary side of the low temperature reaction tank 1, a circulation path connected to the primary side of the low temperature reaction tank 1 is formed again. In this circulation path, the heat medium circulated by the main circulation pump 2 is cooled in the liquefied nitrogen refrigeration machine 4 after bypassing the mechanical refrigeration machine 3 and then supplied again to the low temperature reaction tank 1. .

  Here, generally, when the heat medium temperature is lowered, the liquid viscosity is increased and the pressure loss is increased. Therefore, the pressure loss of the heat exchanger 15 is increased, and the main circulation pump 2 alone has a predetermined heat medium flow rate. There is a possibility that it cannot be secured. Therefore, it is preferable to configure a circulation path passing through the path L8 and to operate the auxiliary circulation pump 30 to ensure a predetermined flow rate.

  Moreover, in the independent operation of the liquefied nitrogen type refrigerator 4, the liquefied nitrogen and the intermediate heat medium are heat-exchanged in the heat exchanger 14 in the liquefied nitrogen type refrigerator 4, and the intermediate heat medium after the heat exchange is incorporated. Circulation to the heat exchanger 15 is performed by operating the circulation pump 17. Note that the cooling temperature of the intermediate heat medium is set to a temperature at which the heat medium does not freeze in the heat exchanger.

  In addition, the heat exchanger 14 in the liquefied nitrogen type refrigerator 4 has a high efficiency and a small heat medium capacity such as a plate fin heat exchanger, a plate type heat exchanger, or a double pipe type heat exchanger. By employing a heat exchanger, the temperature of the intermediate heat medium can be controlled within ± 1 ° C.

  By the way, since the nitrogen gas exhausted from the heat exchanger 14 in the liquefied nitrogen refrigerator 4 has a low temperature, if the heat exchanger 21 is installed in the path L12, it is possible to give cold to other objects. Further, the nitrogen gas can be supplied to other nitrogen gas usage destinations as, for example, a nitrogen gas for safety by accumulating pressure in a buffer tank 22 provided at the subsequent stage of the heat exchanger 21. Here, in order to ensure the cooling capacity of the liquefied nitrogen type refrigerator 4, excess nitrogen gas is exhausted by the pressure control valve 23 provided in the path L15, a certain differential pressure is provided, and liquefied nitrogen is present in the path L12. Make it flow. Thereby, since the pressure of the secondary side of the heat exchanger 14 in the liquefied nitrogen type refrigerator 4 becomes constant, it can be used as a supply source of other nitrogen gas usage destinations.

(Operation method of heat medium cooling device)
In the heat medium cooling device 100 of the present embodiment, a hybrid operation (a liquefied nitrogen type refrigerator) is performed by increasing the heat load in a state where the temperature of the heat medium is decreased (for example, −40 ° C.) by the single operation of the mechanical refrigerator 3. When the operation (4) is required, the following problem may occur. That is, when the intermediate heat medium is at room temperature (for example, 20 ° C.), when the operation of the liquefied nitrogen type refrigerator 4 is started and the line is switched to supply the heat medium to the liquefied nitrogen type refrigerator 4, Since the intermediate heat medium at normal temperature and the heat medium at −40 ° C. exchange heat in the second heat exchanger 15, the heat medium temperature rises. For this reason, it is preferable to perform the pre-cooling operation of the auxiliary circulation path L11 through which the intermediate heating medium circulates before the hybrid operation, and to lower the temperature of the intermediate heating medium in the auxiliary circulation path L11 in advance.

  In the heat medium cooling apparatus 100 described above, the flow rate of the heat medium is constant, the temperature of the heat medium on the secondary side of the low temperature reaction tank 1 at the time t from the start of operation (the detected value of the temperature detector 26), and The timing for switching from the single operation of the mechanical refrigerator described above to the hybrid operation when the allowable value of the temperature difference ΔT with respect to the temperature of the primary heat medium (the detection value of the temperature detector 24) is set to 5 ° C. will be described. To do. Here, FIG. 2 is a flowchart showing an operation method of the heat medium cooling apparatus 100 according to the first embodiment to which the present invention is applied.

  Specifically, first, in step S1 shown in FIG. 2, the set value of the temperature controller 25 on the primary side of the low temperature reaction tank 1 is compared with the set lower limit temperature of the temperature controller 9 of the mechanical refrigerator 3. I do. Here, when the set value of the temperature controller 25 on the primary side of the low temperature reaction tank 1 is equal to or higher than the set lower limit temperature of the temperature controller 9 of the mechanical refrigerator 3, step S2 is performed.

On the other hand, when the set value of the temperature controller 25 is less than the set lower limit temperature of the temperature controller 9, as shown in step S7, as the preparation of the liquefied nitrogen type refrigerator 4, the on-off valve V ₃ , V ₂ is opened and the on-off valves V ₁ , V ₂ and V ₅ are closed. And as shown to step S8 shown in FIG. 2, the independent operation | movement of the liquefied nitrogen type refrigerator 4 mentioned above is started immediately.

  Next, in step S <b> 2 shown in FIG. 2, the current value of the temperature of the heat medium on the primary side (inlet side) of the low temperature reaction tank 1 (that is, the current detected value of the temperature detector 24) and the low temperature reaction tank 1. A comparison is made with a temperature obtained by adding 2 ° C. to the set value of the temperature controller 25 on the primary side. Here, when the detected value of the temperature detector 24 is equal to or higher than the set value of the temperature controller 25 + 2 ° C., the precooling operation of the liquefied nitrogen type refrigerator 4 is started in step S9 described later. On the other hand, when the detected value of the temperature detector 24 is less than the set value of the temperature controller 25 + 2 ° C., step S3 is performed.

Next, in step S3 shown in FIG. 2, before switching to the hybrid operation from a single operation of the mechanical refrigerator 3 reaches the intermediate heat medium at the start time t ₁ of the pre-cooling operation for circulating the secondary circulation path L11 Confirm whether or not.

Here, the method for calculating the starting time t ₁ of the pre-cooling operation is as follows.
First, as described above, the gradient (ΔT / t) of the temperature difference ΔT between the value of the temperature detector 26 and the value of the temperature detector 24 when the time t elapses is set at a constant cycle (for example, every minute). ), It is possible to grasp the fluctuation tendency of the gradient. Therefore, the time t ₂ when the temperature difference ΔT reaches the allowable value ΔT ₂ = 5 ° C. is predicted.

Next, in the pre-cooling operation, using the time t ₂ when the temperature difference ΔT reaches the allowable value ΔT ₂ = 5 ° C. and the start time t _{1 of the} pre-cooling operation for circulating the intermediate heat medium to the sub-circulation path L11. When the start-up time of the liquefied nitrogen type refrigerator 4 is described, the time required for pre-cooling (start-up time) can be expressed as (t ₂ -t ₁ ). Here, the time required for pre-cooling (t ₂ -t ₁ ) is input in advance to the program of the temperature control unit.

For example, the time required for pre-cooling (t ₂ −t ₁ ) is 5 minutes (300 sec), the temperature difference ΔT = 0.3 ° C. when the time t = 60 sec elapses, and the allowable value ΔT ₂ = 5 ° C. If it is after the allowable temperature reaching time _{t 2} is 17 minutes, start time _{t 1} of the pre-cooling operation can be calculated from the following equation (1) after 12 minutes and (700Sec). Therefore, in this case, the pre-cooling operation of the intermediate heat medium is started 12 minutes after the operation of the heat medium cooling device 100 is started.
t ₁ = t / ΔT × ΔT ₂ − (t ₂ −t ₁ ) (1)

Thus, in step S3, if they reached the start time t ₁ of the pre-cooling operation starts precooling operation of the liquid nitrogen refrigerator 4 at step S9. If this respect has not reached the starting time t ₁ of the pre-cooling operation, it performs the step S4.

Next, in step S4 shown in FIG. 2, the on-off valves V ₁ and V ₅ are opened and the on-off valves V _{2 to} V ₄ are closed. And the single operation of the mechanical refrigerator 3 mentioned above is implemented.

Next, in step S5 shown in FIG. 2, similarly to the step S3 described above, to confirm whether or not has reached the intermediate heat medium at the start time t ₁ of the pre-cooling operation for circulating the secondary circulation path L11. Here, if you reached the start time t ₁ of the pre-cooling operation starts precooling operation of the liquid nitrogen refrigerator 4 at step S9. If this respect has not reached the starting time t ₁ of the pre-cooling operation, it performs the step S6.

  Next, in step S6 shown in FIG. 2, the temperature of the heat medium on the primary side (inlet side) of the low-temperature reaction tank 1 (detected value of the temperature detector 24) and the low-temperature reaction tank are the same as in step S2 described above. 1 is compared with the temperature obtained by adding 2 ° C. to the set value of the temperature controller 25 on the primary side. Here, when the detected value of the temperature detector 24 is equal to or higher than the set value of the temperature controller 25 + 2 ° C., the precooling operation of the liquefied nitrogen type refrigerator 4 is started in step S9 described later. On the other hand, when the detected value of the temperature detector 24 is less than the set value + 2 ° C. of the temperature controller 25, the single operation of the mechanical refrigerator 3 is continued as shown in step S4 described above.

Next, in step S10 shown in FIG. 2, the temperature of the intermediate heat medium detected by the temperature detector 18 that detects the temperature of the intermediate heat medium after passing through the heat exchanger 14 and the intermediate heat medium of the temperature controller 19 are detected. Compare with set temperature + 1 ° C (can be set arbitrarily). Here, when the detected temperature of the intermediate heat medium becomes 1 ° C. lower than the set temperature (when pre-cooling is completed), the on-off valves V ₁ and V ₂ are opened and the on-off valve V ₃ is opened in step S11. ~V ₅ closes the, starts a hybrid operation described above.

  Next, in step S12 shown in FIG. 2, the temperature of the heat medium on the secondary side (exit side) of the low temperature reaction tank 1 (that is, the detected value of the temperature detector 26) and the primary side of the low temperature reaction tank 1 ( The temperature difference between the temperature of the heat medium on the inlet side (that is, the detected value of the temperature detector 24) is calculated. When the temperature difference between the secondary side and the primary side of the low-temperature reaction tank 1 is 5 ° C. or more, the hybrid operation is continued. On the other hand, when the said temperature difference is less than 5 degreeC, it progresses to said step S4, a hybrid driving | operation is stopped, and the independent driving | operation of the mechanical refrigerator 3 is started.

  As described above, according to the heat medium cooling device 100 of the present embodiment, the mechanical refrigeration for exchanging heat between the main circulation pump 2 and the refrigerant and the heat medium from the secondary side of the low temperature reaction tank 1 to the circulation path. The machine 3 includes the first heat exchanger 5 because the heat exchanger 15 is arranged in the order of the heat exchanger 15 that exchanges heat between the intermediate heat medium having a freezing point lower than the freezing point of the heat medium and the heat medium. A sub-cooling facility comprising the path L11 for circulating the intermediate heat medium, the heat exchanger 15 and the liquefied nitrogen type refrigerator 4 is assisted while maximizing the capacity of the type refrigerator (main cooling facility) 3 Can be used. And as a sub-cooling facility, a liquefied nitrogen type cooling facility with relatively small required facility power and a cooling facility using an intermediate heat medium are selected, so that a temporary heat load is suppressed while suppressing a significant increase in power cost. It can cope with the increase of. Therefore, when a heat load exceeding the cooling capacity of the mechanical refrigerator 3 is temporarily applied or when it is necessary to cool the heat medium to a set temperature exceeding the capacity, the heat medium is not increased significantly. Can be cooled to a predetermined temperature.

  Further, according to the heat medium cooling device 100 of the present embodiment, the auxiliary circulation path L11 for circulating the intermediate heat medium that can exchange heat with the liquefied nitrogen is provided between the liquefied nitrogen type refrigerator 4 and the circulation path of the heat medium. In addition, the heat exchanger 15 that exchanges heat between the heat medium and the intermediate heat medium is provided in the circulation path. As a result, the heat medium and the liquefied nitrogen are not directly exchanged with heat, so that the heat medium does not solidify. Therefore, even a heat medium having a relatively high freezing point can be used.

  Further, as the heat exchanger 14 in the liquefied nitrogen type refrigerator 4, a heat exchanger having a high efficiency and a small heat medium capacity, such as a plate fin heat exchanger, a plate heat exchanger, or a double pipe heat exchanger, is used. Since it is adopted, the amount of the intermediate heat medium to be circulated in the circulation path L11 can be minimized. Thereby, responsiveness becomes quick and the accuracy of temperature control of the heat medium can be improved.

  Further, by providing the auxiliary circulation pump 30 upstream of the liquefied nitrogen type refrigerator 4 in the circulation path of the heat medium, even when the pressure loss increases due to the increase in viscosity when the heat medium is cooled, the heat medium is necessary. A flow rate can be secured.

  Moreover, it is the structure which provides the path | route L7 used as the bypass line of the mechanical refrigerator 3, and circulates the heat medium which was made into the usable temperature of the mechanical refrigerator 3 below by the independent operation of the liquefied nitrogen type refrigerator 4 In this case, a circulation path that bypasses the mechanical refrigerator 3 can be configured, so that the mechanical refrigerator 3 can be protected.

  Further, according to the operation method of the heat medium cooling device 100 of the present embodiment, when the mechanical refrigerator 3 is switched from the single operation to the hybrid operation, the startup time of the liquefied nitrogen refrigerator 4 is taken into consideration in advance. It is the structure which determines the timing of the start of precooling operation. Accordingly, it is possible to reduce the temperature change of the heat medium accompanying the switching of the circulation path of the heat medium.

Second Embodiment
Next, a second embodiment of the present invention will be described. FIG. 3 is a system diagram of a second embodiment of the heat medium cooling device of the present invention.
As shown in FIG. 3, the heat medium cooling device 200 according to the second embodiment of the present invention has a configuration that does not use an intermediate heat medium, as compared with the configuration of the heat medium cooling device 100 according to the first embodiment. Since it differs in a certain point and the other structure is the same, description is abbreviate | omitted.

  Specifically, a circulation path L11 that circulates the intermediate heating medium, and a heat exchanger that exchanges heat between the intermediate heating medium in the circulation path L11 and the heating medium in the path L5, constituting the heating medium cooling apparatus 100. 15 and a liquefied nitrogen type refrigerator 4 having a heat exchanger 14 for exchanging heat between the intermediate heat medium and liquefied nitrogen, in the heat medium cooling device 200 according to the second embodiment of the present invention, the path A liquefied nitrogen type refrigerator 204 having a heat exchanger 214 for exchanging heat between the heat medium in L5 and the second refrigerant in the path L12 is provided.

  In the present embodiment, the refrigerant used in the mechanical refrigerator 3 in the first embodiment is a first refrigerant. In addition, as the second refrigerant, a refrigerant having a higher cooling capacity than the first refrigerant used in the mechanical refrigerator 3 can be used, and liquefied nitrogen is preferably used. Thereby, it becomes possible to cool a heat medium with liquefied nitrogen with high cooling capacity, without going through an intermediate heat medium.

  A path L16 having a control valve 33 is provided on the primary side of the heat exchanger 214 in the path L12. This path L16 branched from the path L12 functions as a liquefied nitrogen intake line when the precooling operation of the liquefied nitrogen type refrigerator 204 is performed.

  As described above, according to the heat medium cooling apparatus 200 of the present embodiment, since the configuration using the intermediate heat medium is omitted, a simple configuration can be achieved.

<Modification of each embodiment>
The heat medium cooling devices 100 and 200 according to the first and second embodiments described above are examples applied to a low-temperature reaction control device. The low-temperature reaction control device has a low-temperature reaction tank for storing a reaction solution as a heat load, a jacket around the low-temperature reaction tank or a heat exchanger installed in the low-temperature reaction tank, and a heat medium is supplied to the jacket or the heat exchanger. It has the structure to supply and can cool, without freezing a reaction liquid in a heat-transfer surface by supplying the heat medium by which temperature control was carried out beforehand. In addition, the present invention can be applied to the following apparatuses.

  That is, as a heat load device, it can be applied to a cooling tank that performs food freezing or metal heat treatment in place of the low-temperature reaction tank 1, and by supplying a heat medium whose temperature is adjusted in advance into the tank, a stirring fan or the like is required. Therefore, the object can be cooled uniformly. Moreover, it can replace with the low temperature reaction tank 1 as a heat load apparatus, and can apply to the cold trap which cools, condenses, or solidifies a vapor | steam using a coil tube or another heat exchanger. When applied to a cold trap, it is possible to condense and solidify at a uniform temperature with high accuracy by passing a heat medium whose temperature is adjusted in advance through the heat exchanger.

Moreover, the path | route which comprises the circulation path | route of the heat medium of this invention, and the position and number of on-off valves are not limited to the said embodiment, It is possible to change suitably. For example, if the temporary temperature fluctuations of the heat medium in the circulation path is acceptable, it is also possible to omit the passage L9 and the on-off valve V ₅ which serves as a bypass line for bypassing the liquid nitrogen refrigerator.

Furthermore, when it is not necessary to perform the independent operation of the liquefied nitrogen refrigerators 4 and 204, the paths L7 and L8 functioning as bypass lines that bypass the mechanical refrigerator 3 and the on-off valves V ₁ , V ₃ , and V ₄ The auxiliary circulation pump 30, the inverter 31, and the flow rate adjusting means 29 can be omitted.

  The heat medium cooling device of the present invention can be used for temperature control in chemical reaction processes such as organic synthesis and crystallization.

100, 200 ... Heat medium cooling device 1 ... Low temperature reaction tank (heat load device)
2 ... Main circulation pump 3 ... Mechanical refrigerator (main cooling equipment)
4,204 ... Liquid nitrogen type refrigerator (sub cooling equipment)
5 ... Heat exchanger (first heat exchanger)
6, 22 ... Buffer tank 7 ... Heater 8, 18, 24, 26 ... Temperature detector 9, 19, 25, 27 ... Temperature controller (temperature control means)
DESCRIPTION OF SYMBOLS 10 ... Compressor 11, 21 ... Heat exchanger 12, 16, 32 ... Reserve tank 13 ... Expansion valve 14 ... Heat exchanger (3rd heat exchanger)
15 ... Heat exchanger (second heat exchanger)
17 ... circulation pump 20 ... liquefied nitrogen control valve 23 ... pressure control valve 28 ... signal converter 29 ... flow rate detector 29a ... flow rate controller 30 ... sub-circulation pump 31 , 31 '... inverter 33 ... control valves P1-P5 ... connection points L1-L6 ... route L7 ... route (first bypass route)
L8 ... route L9 ... route (second bypass route)
L11 ... circulation route (sub-circulation route)
V _{1 to} V ₅ .. On-off valve (heating medium path switching means)

Claims (5)

A heat medium cooling device for supplying a heat medium whose temperature is controlled to a heat load device,
A circulation path through which the heat medium circulates;
A main circulation pump for circulating a heat medium in the circulation path;
A first heat exchanger provided on the secondary side of the heat load device of the circulation path, for exchanging heat between the refrigerant and the heat medium;
An intermediate heat medium and a heat medium that are provided in the circulation path between the secondary side of the first heat exchanger and the primary side of the heat load device and have a freezing point lower than the freezing point of the heat medium are heated. A second heat exchanger to be exchanged;
A secondary circulation path through which the intermediate heat medium circulates;
A third heat exchanger provided in the auxiliary circulation path for exchanging heat between the intermediate heat medium and liquefied nitrogen;
And a temperature control means for controlling the temperature of the heat medium supplied to the heat load device to a predetermined temperature. A first bypass path provided in the circulation path to connect the primary side and the secondary side of the first heat exchanger;
A second bypass path provided in the circulation path so as to connect the primary side and the secondary side of the second heat exchanger;
The heat medium cooling apparatus according to claim 1, further comprising a heat medium path switching unit.   The heat medium cooling device according to claim 1 or 2, wherein a secondary circulation pump is provided on a primary side of the second heat exchanger in the circulation path. A buffer tank for accumulating nitrogen gas discharged from the third heat exchanger;
The heat medium cooling device according to any one of claims 1 to 3, further comprising a pressure control valve that controls a pressure in the buffer tank. An operation method of the heat medium cooling device according to claim 1,
When cooling to the final target temperature of the heat medium, the heat medium path is arranged so as to supply the heat medium to one or both of the first and second heat exchangers according to the final target temperature. A method of operating a heat medium cooling device, wherein the method is selected.

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