Partial condenser, overhead partial condenser, and air separation device

Abstract

The purpose of the present invention is to provide a partial condenser which has a simple structure and can be made compact in size. The present invention is provided with a heat exchanger block (1), a vapor supply header (3), a residual vapor header (4) and a liquid storage part (2). The heat exchanger block (1) is a plate fin-type heat exchanger block (1) in which an evaporation passage (8) and a condensation distillation passage (9) are stacked. The vapor supply header (3) is provided on a bottom surface of the heat exchanger block (1). The residual vapor header (4) is provided on a top surface of the heat exchanger block (1). The liquid storage part (2) is provided on at least one side surface, in a width direction x orthogonal to a stacking direction z, of the heat exchanger block (1) so as to define an internal space by the side surface and an inner peripheral surface of the liquid storage part (2). The liquid storage part (2) has a liquid supply port (6) for introducing a liquid into the internal space from the outside, a vapor take-out port (5) for taking out vapor in the internal space, and a liquid take-out port (7) for taking out the liquid stored in the internal space.

Description

Sub-cooler, top sub-cooler, air separation device

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[0001] The present invention relates to a sub-cooler having a simple structure and capable of reducing its size, a top sub-cooler using the same, and an air separation device.

[0002] A sub-cooler is used as a separation device or a condenser for partially condensing steam. For such a sub-cooler, a plate fin type heat exchanger in which evaporation passages and condensation distillation passages are formed by plates and fins is applied.

[0003] In the sub-cooler, a liquid is supplied as a refrigerant to the evaporation passage, and a multi-component steam is introduced into the condensation distillation passage from the bottom. The steam introduced into the condensation distillation passage is partially liquefied by heat exchange with the refrigerant in the evaporation passage, and the steam and the liquid come into contact in a countercurrent manner to effect mass transfer. Therefore, the steam rises while concentrating the low-boiling components, and the resulting liquid descends while concentrating the high-boiling components.

[0004] Conventionally, as a sub-cooler as described above, for example, a sub-cooler using a heat exchanger block including an evaporation passage and a condensation distillation passage is known (see, for example, Patent Documents 1 and 2). For example, Patent Document 1 discloses a sub-cooler including a heat exchanger block including an evaporation passage and a condensation distillation passage, and a pressure vessel surrounding the upper and entire outer peripheral sides of the heat exchanger block. The pressure vessel serves as a container for storing the liquid flowing into the evaporation passage by immersing the heat exchanger block.

[0005] Further, for example, Patent Document 2 discloses a sub-cooler (also described as a "de-fragmenter" in Patent Document 2) including a heat exchanger block including an evaporation passage and a condensation distillation passage, and a gas-liquid separator for storing the refrigerant supplied to the heat exchanger block.

[0006] Japanese Patent No. 7308237 Japanese Patent Application Laid-Open No. 11-244603

[0007] The condenser described in Patent Document 1 utilizes the space between the heat exchanger block and the pressure vessel (hereinafter also simply referred to as "vessel") as a refrigerant flow storage space. For this reason, the condenser described in Patent Document 1 has openings on both sides of the lower part of the heat exchanger block and on both sides of the upper part of the heat exchanger block, making it possible to operate the refrigerant passages of the heat exchanger block in the form of a circulating evaporator by the thermal siphon effect.

[0008] However, the heat exchanger described in Patent Document 1 required a large container that could surround the heat exchanger block from above and all sides, resulting in the problem of the entire heat exchanger being large. In addition, the container surrounding the heat exchanger block required various modifications, such as passing piping through it to extract steam from the heat exchanger block, which resulted in the container's structure becoming complex.

[0009] Furthermore, the heat exchanger described in Patent Document 2 also had the problem of requiring a gas-liquid separator and piping for supplying refrigerant from the gas-liquid separator to the heat exchanger block on the outside of the heat exchanger block, which resulted in the entire heat exchanger being made larger.

[0010] Therefore, the present invention aims to provide a condenser with a simple structure and a compact size, a tower top condenser using the same, and an air separation device.

[0011] To achieve the above objective, the present invention provides the following means. [1] A heat exchanger block having an evaporation passage through which an evaporating liquid flows, and a condensation distillation passage through which vapor for condensation distillation by heat exchange with the liquid flowing through the evaporation passage flows; a steam supply header for supplying the vapor to the condensation distillation passage; a residual vapor header for removing the residual vapor distilled in the condensation distillation passage; and a liquid reservoir having an internal space for storing the liquid supplied to the evaporation passage and the liquid discharged from the evaporation passage, wherein the heat exchanger block is a plate-fin type heat exchanger block in which the evaporation passage and the condensation distillation passage, which consist of plates and fins, are alternately stacked; the steam supply header is provided on the bottom surface of the heat exchanger block; the residual vapor header is provided on the top surface of the heat exchanger block; the liquid reservoir is provided on at least one side surface in the width direction perpendicular to the stacking direction of the heat exchanger block, covering both an opening for supplying liquid to the evaporation passage and an opening for discharging a gas-liquid two-phase flow from the evaporation passage, and the internal space is defined by the side surface and the inner circumferential surface of the liquid reservoir. [1] A partial condenser, characterized in that the liquid reservoir has a liquid supply port for introducing liquid from the outside into the internal space, a steam outlet for removing steam from the internal space, and a liquid outlet for removing the liquid stored in the internal space. [2] The partial condenser according to [1], characterized in that the liquid reservoir is provided on one side and the other side in the width direction of the heat exchanger block, and a connecting pipe is provided for allowing the liquid in the two liquid reservoirs provided on the one side and the other side to flow through. [3] A top partial condenser provided at the top of a distillation column, characterized in that it comprises the partial condenser according to [1] or [2], an introduction section having a connecting section for connecting the steam supply header of the partial condenser to the top of the distillation column, and a liquid collector for collecting the liquid flowing down through the condensation distillation passage at the introduction section. [4] An air separation apparatus comprising a double rectification system for extracting nitrogen, oxygen, and argon from air, characterized in that it is equipped with the top condenser described in [3] as the top condenser of an argon column.

[0012] According to the present invention, it is possible to provide a condenser with a simple structure and a compact size, a top condenser using the same, and an air separation device. In particular, in the condenser of the present invention, the liquid reservoir provided on the side of the heat exchanger block serves as a liquid reservoir container for the refrigerant, thus realizing a compact and simple structure in which the heat exchanger block and the liquid reservoir container are integrated.

[0013] This is a schematic partial perspective view showing the general configuration of the partial condenser of the first embodiment of the present invention. This is a schematic plan view showing the partial condenser shown in Figure 1. This is an explanatory diagram for explaining the configuration of the evaporation passage in the partial condenser shown in Figure 1. This is an explanatory diagram for explaining the configuration of the condensation distillation passage in the partial condenser shown in Figure 1. This is a schematic plan view showing the partial condenser of the second embodiment of the present invention. This is a schematic plan view showing the top partial condenser of the third embodiment of the present invention. This is a schematic diagram illustrating an air separation apparatus of the fourth embodiment of the present invention, and is a system diagram showing the general configuration of the entire air separation apparatus. This is a schematic diagram illustrating an air separation apparatus using a conventional partial condenser as a top partial condenser of an argon column, and is a system diagram showing the general configuration of a part of the air separation apparatus.

[0014] The present invention will be described below based on preferred embodiments.

[0015] <First Embodiment> Figure 1 is a schematic partial perspective view showing the general configuration of the fractional condenser of the first embodiment, and Figure 2 is a schematic plan view showing the fractional condenser shown in Figure 1. As shown in Figures 1 and 2, the fractional condenser 10A of this embodiment is a fractional condenser 10A comprising a heat exchanger block 1, a steam supply header 3, a residual steam header 4, and a liquid reservoir 2.

[0016] The heat exchanger block 1 has an evaporation passage 8 through which the liquid to be evaporated flows, and a condensation distillation passage 9 through which vapor for condensation distillation, which exchanges heat with the liquid flowing through the evaporation passage 8, flows. The vapor supply header 3 is for supplying vapor to the condensation distillation passage 9. The residual vapor header 4 is for removing the residual vapor distilled in the condensation distillation passage 9. The liquid reservoir 2 is for storing the liquid supplied to the evaporation passage 8 and the liquid that flows out of the evaporation passage 8.

[0017] In the condenser 10A of this embodiment, the evaporating liquid flowing through the evaporation passage 8 receives heat from the vapor flowing through the condensation distillation passage 9, and a portion of it evaporates. This liquid flowing through the evaporation passage 8 functions as a refrigerant in the condenser 10A. The "evaporating liquid" flowing through the evaporation passage 8 is sometimes referred to as the "liquid as a refrigerant" or simply the "refrigerant." In the condenser 10A of this embodiment, a liquid reservoir 2 for storing the liquid as a refrigerant is directly provided on the heat exchanger block 1, and a compact and simple structure is realized in which the heat exchanger block 1 and the liquid reservoir container for storing the refrigerant are integrated.

[0018] The following describes each component in detail. In Figures 1 and 2, the arrows labeled V and L indicate the direction of fluid flow. The V attached to the arrow indicates that the fluid is vapor. The L attached to the arrow indicates that the fluid is liquid. The W attached to V and L indicates that the fluid is warm. The c attached to V and L indicates that the fluid is cold. When attached to w or c, i indicates that the fluid is coming in, and o indicates that the fluid is going out.

[0019] In Figure 1, the arrow denoted by z indicates the direction in which the evaporation passages 8 and condensation / distillation passages 9, consisting of plates and fins, are alternately stacked in the heat exchanger block 1. The direction indicated by the arrow denoted by z is called the stacking direction z. The arrow denoted by y indicates the vertical direction (up and down direction) defined by the bottom and top surfaces of the heat exchanger block 1. Here, the vertical direction of the heat exchanger block 1 is the direction parallel to the main steam flow direction in the condensation / distillation passages. The direction indicated by the arrow denoted by y is called the vertical direction y. In the condenser 10A of this embodiment, the stacking direction z and the vertical direction y are orthogonal. The arrow denoted by x indicates a direction orthogonal to both the vertical direction y and the stacking direction z. The direction indicated by the arrow denoted by x is called the width direction x of the heat exchanger block 1. The width direction x of the heat exchanger block 1 is sometimes simply referred to as "width direction x".

[0020] <Heat Exchanger Block> The heat exchanger block 1 is composed of plates and fins and has an evaporation passage 8 through which a liquid refrigerant flows, and a condensation distillation passage 9 through which vapor flows for condensation distillation by exchanging heat with the refrigerant flowing through the evaporation passage 8. The heat exchanger block 1 is a plate-fin type heat exchanger block.

[0021] As shown in Figures 1 and 2, the evaporation passage 8 is provided extending from the lower to the upper part of the heat exchanger block 1. On the lower side of the evaporation passage 8, as shown in Figure 3, a liquid introduction passage 15 is provided for introducing the liquid (refrigerant) from the liquid reservoir 2, and a liquid introduction opening 15a is provided at the entrance of the liquid introduction passage 15. Here, Figure 3 is an explanatory diagram illustrating the configuration of the evaporation passage 8 in the condenser 10A shown in Figure 1.

[0022] Furthermore, a gas-liquid two-phase fluid outlet passage 17 is provided on the upper side of the evaporation passage 8 for discharging the gas-liquid two-phase fluid, and a gas-liquid two-phase fluid outlet opening 17a is provided at the outlet of the gas-liquid two-phase fluid outlet passage 17. Here, although the details will be described later, the gas-liquid two-phase fluid is a fluid that contains vapor obtained when the liquid introduced into the evaporation passage 8 receives heat from the fluid flowing through the condensation distillation passage 9, and a portion of it evaporates.

[0023] The liquid inlet passage 15 and the gas-liquid two-phase fluid outlet passage 17 of the evaporation passage 8 are formed by orienting fins sideways, as shown in Figure 3. In Figure 3, the direction of the lines drawn on the evaporation passage 8 indicates the direction of the fins provided in the evaporation passage 8.

[0024] As shown in Figures 1 and 2, the condensing distillation passage 9 is provided extending from the lower end to the upper end of the heat exchanger block 1. As shown in Figure 4, the lower end of the condensing distillation passage 9 is a steam inlet opening 9a for introducing steam, and the upper end is a residual steam outlet opening 9b for releasing residual steam. Here, the condensing distillation passage 9 shown in Figure 4 has a convergence passage 39 at the top of the condensing distillation passage 9 for concentrating the condensing distillation passage 9 to the center in the width direction x, and a central passage 41 communicating with the convergence passage 39. However, the condensing distillation passage 9 does not necessarily have to have such a convergence passage 39 and a central passage 41. If there is no convergence passage 39 and a central passage 41, although not shown in the figure, the entire upper end of the condensing distillation passage 9 becomes a residual steam outlet opening 9b for releasing residual steam. Here, Figure 4 is an explanatory diagram for explaining the configuration of the condensing distillation passage 9 in the partial condenser 10A shown in Figure 1. As with Figure 3, the direction of the lines indicated in Figure 4 for the condensation distillation passage 9 indicates the direction of the fins provided in the condensation distillation passage 9.

[0025] <Steam Supply Header> The steam supply header 3 is provided on the bottom surface of the heat exchanger block 1 to supply steam to the condensation distillation passages 9. As shown in Figures 1 and 2, the steam supply header 3 is provided so as to cover the entire bottom surface of the heat exchanger block 1 and is provided to communicate with all of the condensation distillation passages 9 formed in the heat exchanger block 1.

[0026] <Residual Steam Header> The residual steam header 4 is for extracting residual steam distilled in the condensation distillation passage 9, and is provided on the top surface of the heat exchanger block 1 so as to cover the residual steam outlet opening 9b. In the condenser 10A of this embodiment, as shown in Figures 1, 2 and 4, the residual steam outlet opening 9b is configured to open in a part of the top surface of the heat exchanger block 1. Therefore, the residual steam header 4 is provided in a part of the width direction x of the top surface of the heat exchanger block 1 so as to cover the area where the residual steam outlet opening 9b is open. However, as described above, if the condensation distillation passage 9 does not have a concentration passage 39 and a central passage 41, and the entire upper end of the condensation distillation passage 9 becomes the residual steam outlet opening 9b for releasing residual steam, the residual steam header 4 may be provided so as to cover the entire top surface of the heat exchanger block 1, although this is not shown in the illustration.

[0027] <Liquid reservoir section> The liquid reservoir section 2 has an internal space for storing the liquid supplied to the evaporation passage 8 and the liquid that flows out from the evaporation passage 8.

[0028] The liquid reservoir 2 is provided on at least one side surface of the heat exchanger block 1 in the width direction x (i.e., the direction perpendicular to the stacking direction z), such that the internal space is defined by the side surface and the inner circumferential surface of the liquid reservoir 2. The liquid reservoir 2 only needs to be provided on at least one side surface of the heat exchanger block 1 in the width direction x, but it is preferable that one is provided on each of the two sides of the heat exchanger block 1 in the width direction x, as shown in Figures 1 and 2.

[0029] The liquid reservoir 2 shown in Figures 1 and 2 is provided to cover the entire area of ​​each side surface in the width direction x of the heat exchanger block 1. However, for example, if both the area where the liquid inlet opening 15a and the gas-liquid two-phase fluid outlet opening 17a of the evaporation passage 8 are provided on the side surface in the width direction x of the heat exchanger block 1 are included within the internal space of the liquid reservoir 2, the liquid reservoir 2 may be provided to cover only a part of the width direction x of the heat exchanger block 1. In other words, the liquid reservoir 2 only needs to be provided to cover both the liquid inlet opening 15a for supplying liquid to the evaporation passage 8 provided on the side surface in the width direction x of the heat exchanger block 1 and the gas-liquid two-phase fluid outlet opening 17a for discharging the gas-liquid two-phase flow from the evaporation passage 8.

[0030] There are no particular restrictions on the shape of the liquid reservoir 2. For example, it can be installed on one side of the heat exchanger block 1 in the width direction x, and the internal space for storing the liquid supplied to the evaporation passage 8 can be defined by the side and the inner surface of the liquid reservoir 2. Figures 1 and 2 show examples in which hollow, semi-cylindrical liquid reservoirs 2 are provided on one side and the other side of the heat exchanger block 1, respectively.

[0031] The liquid reservoir 2 has a liquid supply port 6 for introducing liquid from the outside into the internal space of the liquid reservoir 2, a steam outlet 5 for removing steam from the internal space of the liquid reservoir 2, and a liquid outlet 7 for removing the liquid stored in the internal space of the liquid reservoir 2. As shown in Figures 1 and 2, the steam outlet 5 for removing steam from the internal space of the liquid reservoir 2 is provided at the top of the liquid reservoir 2, and the liquid outlet 7 for removing the liquid stored in the internal space of the liquid reservoir 2 is provided at the bottom of the liquid reservoir 2. The liquid supply port 6 for introducing liquid from the outside into the internal space of the liquid reservoir 2 is provided on the side of the liquid reservoir 2.

[0032] [Operation Description] Next, the operation of the fractional reducer 10A of this embodiment, configured as described above, will be explained based on Figures 1 to 4.

[0033] First, a refrigerant liquid (Lc) is stored in the internal space of the liquid reservoir 2 (hereinafter sometimes simply referred to as "inside the liquid reservoir 2"). The liquid (Lc) stored in the liquid reservoir 2 is introduced into the evaporation passage 8 through the liquid inlet opening 15a of the heat exchanger block 1 and the liquid inlet passage 15.

[0034] On the other hand, the multi-component vapor (Vw) to be subjected to condensate distillation is introduced into the condensate distillation passage 9 from an external source via the vapor supply header 3.

[0035] The liquid (Lc) introduced into the evaporation passage 8 receives heat from the fluid flowing through the condensation and distillation passage 9, and a portion of it evaporates. Due to this evaporation, the density of the fluid flowing through the evaporation passage 8 becomes less than the density of the liquid stored in the liquid reservoir 2, creating an upward flow. This flow is then returned to the liquid reservoir 2 as a gas-liquid two-phase fluid (Lc + Vc) through the gas-liquid two-phase fluid outlet opening 17a via the gas-liquid two-phase fluid outlet passage 17 of the heat exchanger block 1. The gas (Vc) discharged from the gas-liquid two-phase fluid outlet opening 17a is discharged to the outside through the vapor outlet 5 of the liquid reservoir 2, and the liquid (Lc) is stored again in the liquid reservoir 2.

[0036] Meanwhile, the vapor (Vw) introduced into the condensation distillation passage 9 rises within the passage, and as it rises, a portion of it condenses due to heat exchange with the fluid flowing through the evaporation passage 8, producing a descending liquid. Thus, countercurrent contact occurs between the rising gas and the descending liquid, and as the vapor rises, the low-boiling point components become concentrated and are removed to the outside through the residual vapor outlet opening 9b and the residual vapor header 4 at the top.

[0037] On the other hand, the liquid produced by condensation in the condensation distillation passage 9 becomes concentrated with high-boiling-point components as it descends, and is discharged via the steam supply header 3 at the bottom.

[0038] In the condenser 10A of this embodiment, as described above, the liquid reservoir 2 for storing the liquid (Lc) introduced into the evaporation passage 8 is provided on at least one side of the heat exchanger block 1 in the width direction x. Therefore, it is not necessary to house the entire heat exchanger block 1 in a pressure vessel for storing the liquid (Lc), as is the case with conventional condensers. As a result, the footprint of the condenser 10A of this embodiment can be reduced compared to conventional condensers in which the entire heat exchanger block 1 is housed in a pressure vessel. For example, the condenser 10A of this embodiment can reduce the area required for installation (i.e., footprint) by about 20% compared to the conventional condenser described above, and a compact condenser 10A in which the heat exchanger block 1 and the liquid reservoir 2 as a liquid reservoir container for the refrigerant are integrated is realized.

[0039] Furthermore, while the piping for extracting steam from the residual steam header of the condenser 10A had to pass through the pressure vessel in the prior art, this is no longer necessary, resulting in a simpler design.

[0040] <Second Embodiment> Next, a second embodiment of the present invention will be described with reference to Figure 5. Figure 5 is a schematic plan view showing the second embodiment of the second embodiment of the second embodiment. In this second embodiment, the same reference numerals are used for parts that are the same as those in the first embodiment, and their descriptions may be omitted.

[0041] As shown in Figure 5, the fractional condenser 10B of the second embodiment is a fractional condenser 10B that, like the fractional condenser 10A of the first embodiment (see Figure 2), is equipped with a heat exchanger block 1, a steam supply header 3, a residual steam header 4, and a liquid reservoir 2.

[0042] In the second embodiment of the heat exchanger block 10B, liquid reservoirs 2 are provided on one side and the other side in the width direction x of the heat exchanger block 1. The heat exchanger block 10B is equipped with a connecting pipe 13 for circulating the liquid (Lc) in the two liquid reservoirs 2 provided on one side and the other side of the heat exchanger block 1.

[0043] By providing a communication pipe 13 for allowing the liquid (Lc) in the two liquid reservoirs 2 to flow through, as in the condenser 10B of the second embodiment, the liquid levels of the liquid (Lc) stored in the two liquid reservoirs 2 can be made uniform. For example, when there is a difference in the liquid levels of the liquid (Lc) stored in the liquid reservoir 2 provided on one side surface of the heat exchanger block 1 and the liquid reservoir 2 provided on the other side surface of the heat exchanger block 1, a pressure difference may occur in the liquid introduction opening 15a and the gas-liquid two-phase fluid outlet opening 17a of the heat exchanger block 1, resulting in a non-uniform flow in the evaporation passage 8. When the non-uniform flow in the evaporation passage 8 reaches an extremely extreme state, liquid may completely evaporate in a part of the evaporation passage 8, causing accumulation of solidified impurity components in the gas-liquid two-phase fluid and clogging of the flow path. When problems as described above occur, a non-uniform flow occurs and the heat transfer performance deteriorates. By providing a communication pipe 13 for allowing the liquid (Lc) in the two liquid reservoirs 2 to flow through, the flow in the evaporation passage 8 becomes uniform, and the occurrence of problems as described above can be effectively suppressed, enabling more efficient operation of the condenser 10B.

[0044] As shown in FIG. 5, the communication pipe 13 for allowing the liquid (Lc) in the two liquid reservoirs 2 to flow through is connected to the bottom surface of each liquid reservoir 2 and is constituted by a pipe communicating the two liquid reservoirs 2. In the condenser 10B of the second embodiment, a liquid outlet 7 for taking out the liquid (Lc) in the liquid reservoir 2 is provided in the middle of the communication pipe 13 that communicates the two liquid reservoirs 2. Therefore, when taking out the liquid (Lc) in the liquid reservoir 2 from the liquid outlet 7, the liquid (Lc) can be taken out from the two liquid reservoirs 2 simultaneously through the communication pipe 13. For this reason, when taking out the liquid (Lc) from the liquid outlet 7, the liquid levels of the liquid (Lc) stored in the two liquid reservoirs 2 can be made uniform.

[0045] <Third Embodiment> Next, the top condenser of the third embodiment of the present invention will be described with reference to FIG. 6. FIG. 6 is a plan view schematically showing the top condenser of the third embodiment of the present invention. In this third embodiment, the same components as those in the first embodiment may be denoted by the same reference numerals and the description thereof may be omitted.

[0046] As shown in FIG. 6, the top condenser 110 of the third embodiment is provided at the top 31 of the distillation column and is a top condenser 110 for generating reflux liquid. The top condenser 110 includes a condenser 10A of the first embodiment shown in FIG. 1, an introduction part 12A having a communication part 12 that connects the vapor supply header 3 of the condenser 10A and the top 31 of the distillation column, and a liquid collector 20 for collecting the liquid flowing down through the condensation distillation passage 9 to the introduction part 12A.

[0047] In the top condenser 110 configured as described above, the vapor supplied from the top 31 of the distillation column to the condenser 10A passes through the vapor rising path 23 of the liquid collector 20, passes through the communication part 12 and the vapor supply header 3, and is supplied to the heat exchanger block 1. The liquid flowing down from the heat exchanger block 1 is collected by the liquid collector 20 through the vapor supply header 3 and the communication part 12.

[0048] The liquid collector 20 includes, for example, a liquid collection path 21 for collecting the flowing-down liquid, an umbrella 22 for guiding the flowing-down liquid to the liquid collection path 21, a vapor rising path 23 that serves as a passage for the vapor in the column to pass through and rise, a peripheral path 24 provided on the column wall 30 and connected to the liquid collection path 21, and a liquid extraction pipe 25 connected to the peripheral path 24 for extracting the liquid.

[0049] In the top condenser 110 configured as described above, the liquid flowing down through the vapor supply header 3 is collected into the liquid collection path 2' by the umbrella 22, collected from each liquid collection path 21 into the peripheral path 24, and extracted from the liquid extraction pipe 25 connected to the peripheral path 24.

[0050] <Fourth Embodiment> Next, the air separation apparatus of the fourth embodiment of the present invention will be described with reference to FIG. 7. FIG. 7 is a diagram schematically explaining the air separation apparatus of the fourth embodiment and is a system diagram showing the schematic configuration of the entire air separation apparatus. In this fourth embodiment, the same components as those in the third embodiment may be denoted by the same reference numerals and their description may be omitted.

[0051] As shown in Figure 7, the air separation apparatus 200 of the fourth embodiment is an air separation apparatus consisting of a double rectification system that extracts nitrogen, oxygen, and argon from air. The air separation apparatus of the fourth embodiment is equipped with the top condenser 110 of the third embodiment shown in Figure 6 as the top condenser of the argon column.

[0052] The air separation apparatus 200 of the fourth embodiment is a device for extracting nitrogen, oxygen, and argon from air, and its main components include an air compressor 40, a main heat exchanger 50, a distillation column consisting of a high-pressure column 60, a low-pressure column 80, a crude argon column 90, and a deoxidation column 100, a main condenser 70, a top condenser 110, pumps 81 and 101, and an outer tank 120. In the air separation apparatus 200 shown in Figure 7, the argon column is divided into a crude argon column 90 and a deoxidation column 100, and the top condenser 110 of the third embodiment described above is provided at the top of the deoxidation column 100.

[0053] Here, the main heat exchanger 50 is for exchanging heat with the raw air. The main condenser 70 is for exchanging heat between the bottom liquid of the low-pressure column 80 and the steam supplied from the top of the high-pressure column 60. The outer tank 120 is for keeping the distillation columns and heat exchangers that make up the air separation unit 200 cool, and the outer tank 120 may be, for example, one that has an insulating material.

[0054] In the air separation apparatus 200 shown in Figure 7, for example, nitrogen is recovered from the main heat exchanger 50 as low-pressure nitrogen gas (LPGN) and medium-pressure nitrogen gas (MPGN). Oxygen is recovered as oxygen gas (GO). In addition, liquefied oxygen (LO) is recovered from the main condenser 70.

[0055] In the air separation unit 200, first, the raw air is compressed by the air compressor 40, and the compressed raw air is introduced into the high-pressure column 60 and the low-pressure column 80 for distillation. Then, the argon-enriched flow is taken out from the low-pressure column 80 and sent to the crude argon column 90. The top of the crude argon column 90 is in communication with the bottom of the deoxidation column 100, and the liquid accumulated at the bottom of the deoxidation column 100 is supplied to the top of the crude argon column 90 by the pump 101. In addition, a top condenser 110 for generating reflux liquid is provided at the top of the deoxidation column 100.

[0056] In the crude argon column 90 and the deoxidation column 100, oxygen, a high-boiling-point component, is concentrated at the bottom, while argon, a low-boiling-point component, is concentrated towards the top. In the top condenser 110 located at the top of the deoxidation column 100, vapor from the deoxidation column 100 is introduced into the condensation distillation passage 9 of the heat exchanger block 1 through the liquid collector 20 (see Figure 6, the same applies hereafter). The vapor introduced into the condensation distillation passage 9 is partially liquefied as heat is removed by the refrigerant passing through the evaporation passage 8 of the heat exchanger block 1, and then comes into contact with the liquid in a countercurrent. As a result, in the heat exchanger block 1, nitrogen, which has the lowest boiling point among the impurity components, is concentrated at the top, and argon, a high-boiling-point component, is concentrated at the bottom. The nitrogen vapor (PG) concentrated at the top of the heat exchanger block 1 is discharged from the top of the heat exchanger block 1, and high-purity liquid argon (Lar) is extracted from the bottom of the heat exchanger block 1.

[0057] Liquid air supplied from the bottom of the high-pressure tower 60 is used as the refrigerant for the top condenser 110. Specifically, liquid air is supplied to the top condenser 110 from the bottom of the high-pressure tower 60 and stored in a liquid reservoir 2 provided on the side of the heat exchanger block 1. The stored liquid air flows into the evaporation passage 8, receives heat, and a portion of it evaporates. The vapor generated by evaporation is taken out from a vapor outlet 5 (see Figure 6, hereafter the same) provided in the liquid reservoir 2 and supplied to the low-pressure tower 80. In addition, liquid air stored in the liquid reservoir 2 is taken out from a liquid outlet 7 (see Figure 6, hereafter the same) provided at the bottom of the liquid reservoir 2 and supplied to the low-pressure tower 80 in the same way as the vapor taken out from the vapor outlet 5.

[0058] Here, for comparison with the air separation apparatus 200 of the fourth embodiment, an example of an air separation apparatus using a conventional partial condenser as a top partial condenser of an argon column will be described with reference to Figure 8. Figure 8 is a schematic diagram illustrating an air separation apparatus using a conventional partial condenser as a top partial condenser of an argon column, and is a system diagram showing the schematic configuration of a part of the air separation apparatus. The air separation apparatus 300 shown in Figure 8 is a comparative example in which a partial condenser configured in the same way as the partial condenser described in Patent Document 1 (Japanese Patent No. 7308237) is applied as the top partial condenser 310 of an argon column (more specifically, a deoxidation column 100 as an argon column).

[0059] The top condenser 310 in the air separation device 300 shown in Figure 8 comprises a heat exchanger block 301, a container 311 surrounding the top and all sides of the heat exchanger block 301, and a gas-liquid separation unit 312. In the top condenser 310, steam from the deoxidation tower 100 is introduced into the heat exchanger block 301 through the gas-liquid separation unit 312. The steam introduced into the heat exchanger block 301 is partially liquefied within the heat exchanger block 301, with low-boiling-point nitrogen concentrated at the top and high-boiling-point argon concentrated at the bottom. As a result, nitrogen-concentrated steam is extracted from the top and sides of the heat exchanger block 301, and high-purity liquid argon is extracted from the bottom of the heat exchanger block 301.

[0060] Liquid air supplied from the bottom of the high-pressure tower 60 is used as the refrigerant for the top condenser 310. The liquid air used as the refrigerant is supplied to and stored in a container 311 surrounding the heat exchanger block 301. Some of the liquid air stored in the container 311 evaporates as it passes through the heat exchanger block 301. The resulting vapor is then extracted from the top of the container 311, and the liquid air is extracted from the bottom of the container 311. The vapor and liquid air extracted from the container 311 are supplied to the low-pressure tower 80.

[0061] In a conventional top-of-the-column heat exchanger 310 using a heat exchanger as shown in Figure 8, the entire heat exchanger block 301 is housed in a pressure vessel 311, which results in a larger size for the heat exchanger. Furthermore, when the entire heat exchanger block 301 is housed in the vessel 311, complex processing such as passing piping through the vessel 311 is required, which increases the manufacturing cost.

[0062] On the other hand, in the fourth embodiment of the air separation device 200 of the present invention, as shown in Figure 7, the top condenser 110 has a liquid reservoir 2 on the side of the heat exchanger block 1, which allows for a smaller condenser size. Furthermore, the top condenser 110 shown in Figure 7 does not require complex processing such as passing piping through the liquid reservoir 2, thus reducing the manufacturing cost of the top condenser 110 and the outer tank 120.

[0063] 1...Heat exchanger block, 2...Liquid reservoir, 3...Steam supply header, 4...Residual steam header, 5...Steam outlet, 6...Liquid supply port, 7...Liquid outlet, 8...Evaporation passage, 9...Condensing and distillation passage, 9a...Steam inlet opening, 9b...Residual steam outlet opening, 10A, 10B...Collision condenser, 12...Communication section, 12A...Inlet section, 13...Communication pipe, 15...Liquid inlet passage, 15a...Liquid inlet opening, 17...Gas-liquid two-phase fluid outlet passage, 17a...Gas-liquid two-phase fluid outlet opening 17a, 20...Liquid collector, 21...Liquid collection passage, 22 ...Umbrella, 23...Steam rising passage, 24...Circular passage, 25...Liquid outlet pipe, 30...Column wall, 31...Column top, 39...Collection passage, 41...Central passage, 40...Air compressor, 50...Main heat exchanger, 60...High pressure column, 70...Main condenser, 80...Low pressure column, 81, 101...Pumps, 90...Crude argon column, 100...Deoxidation column, 110...Column top condenser, 120...Outer tank, 200...Air separation device, 300...Air separation device, 301...Heat exchanger block, 310...Column top condenser, 311...Container, 312...Gas-liquid separation section.

Claims

1. A heat exchanger block having an evaporation passage through which a liquid to be evaporated flows, and a condensation distillation passage through which vapor for condensation distillation by heat exchange with the liquid flowing through the evaporation passage flows; a steam supply header for supplying the vapor to the condensation distillation passage; a residual vapor header for removing the residual vapor distilled in the condensation distillation passage; and a liquid reservoir having an internal space for storing the liquid supplied to the evaporation passage and the liquid discharged from the evaporation passage, wherein the heat exchanger block is a plate-fin type heat exchanger block in which the evaporation passage and the condensation distillation passage, each consisting of plates and fins, are alternately stacked; the steam supply header is provided on the bottom surface of the heat exchanger block; the residual vapor header is provided on the top surface of the heat exchanger block; the liquid reservoir is provided on at least one side surface in the width direction perpendicular to the stacking direction of the heat exchanger block, covering both an opening for supplying liquid to the evaporation passage and an opening for discharging a gas-liquid two-phase flow from the evaporation passage, and the internal space is defined by the side surface and the inner circumferential surface of the liquid reservoir. The liquid reservoir is characterized by having a liquid supply port for introducing liquid from the outside into the internal space, a steam outlet for removing steam from the internal space, and a liquid outlet for removing the liquid stored in the internal space.

2. The heat exchanger block is provided with liquid reservoirs on one side and the other side in the width direction, and is provided with a connecting pipe for circulating the liquid in the two liquid reservoirs provided on the one side and the other side, as described in claim 1.

3. A top condenser provided at the top of a distillation column, comprising: a condenser according to claim 1 or 2; an introduction section having a communication section that connects the vapor supply header of the condenser to the top of the distillation column; and a liquid collector for collecting the liquid flowing down through the condensation distillation passage to the introduction section.

4. An air separation apparatus comprising a double rectification system for extracting nitrogen, oxygen, and argon from air, characterized in that the top condenser described in claim 3 is provided as the top condenser of the argon column.

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