JP2787593B2 - Evaporator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to evaporation in which heat exchange is performed between a liquid medium in a first fluid passage and a fluid in a second fluid passage to evaporate the liquid medium in the first fluid passage. About the vessel.

[Conventional technology]

As an example of the conventional evaporator, the liquid in the second fluid passage is nitrogen gas, which condenses the liquefied oxygen that is used between the upper and lower towers of the double rectification column of the air liquefaction separator. A description will be given using a condensation evaporator.

For example, as described in JP-A-56-56592, the vertical direction is divided by a number of parallel partition plates, and two chambers of a first fluid passage (oxygen chamber) and a second fluid passage (nitrogen chamber) are formed. A so-called plate-fin heat exchanger, which is alternately stacked adjacently, is often used.

The oxygen chamber, which is the first fluid passage of such a plate fin type condensing evaporator, has a vertically arranged heat transfer plate therein to form a large number of vertical evaporation passages, Both upper and lower ends are opened, and the lower end is used as an inlet for liquefied oxygen, and the upper end is used as an outlet for a mixed flow of oxygen gas and liquefied oxygen. The oxygen chamber is filled with liquefied oxygen by immersing the entire condensing evaporator in a liquid medium (liquefied oxygen) that accumulates in the bottom space of the upper tower. Heat exchange with nitrogen gas introduced from the lower tower into the nitrogen chamber, which is a fluid passage, is heated by cooling and condensing it, and a part of it evaporates to become bubbles of oxygen gas, and the vaporization flow path To rise. The liquefied oxygen rises in the oxygen chamber due to the density difference between the gas-liquid mixed phase of the oxygen gas and the liquefied oxygen and the liquefied oxygen outside the oxygen chamber, and forms a circulating flow inside and outside the condensing evaporator.

On the other hand, in the nitrogen chamber, a vertical heat transfer plate is similarly arranged in the oxygen chamber, and a large number of vertical condensation flow paths are formed in a chamber whose four circumferences are sealed. It is connected to the lower tower via the provided header. Then, nitrogen gas in the upper part of the lower tower is introduced from the upper header into the condensation flow path as a downward flow, and liquefied nitrogen condensed by performing heat exchange with the liquefied oxygen in the condensation flow path is derived from the lower header. ing.

[Problems to be solved by the invention]

However, such a conventional condensing evaporator is entirely immersed in liquefied oxygen in the upper column bottom space, and is used unless a large amount of liquefied oxygen is stored in the space. Function could not be fully exhibited. For this reason, the start-up time of the apparatus is long, or the amount of liquefied oxygen released at the time of stoppage is increased, resulting in a loss of power cost. Further, by holding a large amount of liquefied oxygen, there is a great security problem in preparation for an emergency.

In addition, since the entire condensing evaporator is immersed in liquefied oxygen, the pressure of liquefied oxygen at the lower part of the condensing evaporator rises due to the liquid depth of the liquefied oxygen, and a boiling point rises. The liquefied oxygen flowing into the evaporation flow path is in a supercooled state. Therefore, in the lower part of the oxygen chamber, liquefied oxygen rising in the evaporating flow passage must be heated to the boiling start temperature by convective heat transfer having a low heat transfer efficiency, thereby lowering the heat transfer efficiency of the flow passage, and reducing the oxygen flow in the oxygen chamber. In order to secure a temperature difference from the nitrogen chamber, it is necessary to increase the condensation temperature of the nitrogen gas. Therefore, the pressure of the nitrogen gas, that is, the operating pressure of the lower tower must be increased, which is necessary for the compression of the raw material air. The power was increasing.

Furthermore, in the nitrogen chamber on the condensation side, nitrogen gas flows down while condensing nitrogen gas in the vertical condensation flow path, so that the amount of liquefied nitrogen increases at the lower part of the flow path, forming a thick liquid film, and the surface of the heat transfer surface becomes thicker. Since it covers, this becomes a heat resistance layer and lowers the heat transfer performance.

In particular, in the case of a condensing evaporator used for a large-sized air liquefaction separation device, the size in the height direction must be increased due to the restriction in the width direction due to the installation location, so the influence of the liquid depth of the liquefied oxygen described above In addition, the influence of the liquid film of condensed liquefied nitrogen increases, the heat exchange efficiency decreases, and the amount of liquefied oxygen required to immerse the condensing evaporator increases, resulting in startup time problems and security problems. growing.

Therefore, the present invention reduces the required amount of liquefied oxygen (liquid medium) on the side of the oxygen chamber (first fluid passage) and reduces the influence of the liquid depth of the liquefied oxygen, thereby reducing the nitrogen chamber (second fluid passage). It is an object of the present invention to provide an evaporator that can reduce a required temperature difference between the evaporator and the evaporator, and can further reduce a decrease in heat transfer performance due to a condensate in the nitrogen chamber.

[Means for solving the problem]

In order to achieve the above object, a first configuration of a condensing evaporator of the present invention is an evaporator that performs heat exchange between a liquid medium in a first fluid passage and a fluid in a second fluid passage. The fluid passages and the second fluid passages are mainly alternately stacked in the vertical direction, and a liquid medium introduction unit for introducing the liquid medium into the first fluid passage is provided at one end of the first fluid passage, and the other end is opened. The second fluid passage is provided with a fluid introduction means for introducing the fluid into the second fluid passage at one end thereof, and the other end thereof is provided as an outlet. Further, a second configuration of the present invention is characterized in that the first fluid passage has a rising gradient from a liquid medium introduction side to a discharge side. Further, the third configuration is
The first fluid passage and the second fluid passage are partitioned and defined by a partition plate disposed between the respective passages,
Waveform heat transfer fins are arranged between the partition plates.

A fourth configuration is such that the liquid medium introduction means communicates with the liquid medium introduction end of the first fluid passage, and a plurality of liquid reservoirs and / or liquid receivers arranged in upper and lower stages, and the liquid reservoir and / or Alternatively, there is provided a liquid medium supply means for supplying a liquid medium to the liquid receiver, and the liquid reservoir and / or the liquid receiver are open at the top. According to a fifth configuration, in the fourth configuration, the liquid medium supply unit includes: a liquid supply pipe disposed along the liquid reservoir and / or the liquid receiver disposed in the upper and lower multi-stages; And / or a liquid medium supply hole provided on a side wall of the liquid receiver and communicating the liquid supply pipe with each of the liquid reservoirs and / or the liquid receiver.
A sixth configuration according to the fourth configuration, wherein a plurality of liquids having an open upper part that communicate with the outlet end of the first fluid passage and receive the liquid medium flowing out from the outlet end of the first fluid passage are provided. It is characterized in that the receivers are provided in multiple stages in the upper and lower parts, and a liquid return flow path for returning the liquid medium flowing out to the liquid receiver to the liquid reservoir is provided.

A seventh configuration is the sixth configuration, wherein the liquid return flow path is any one of a pipe or a gutter, or a flow path provided between the first fluid passages so as not to be adjacent to the second fluid passage. Characterized by the following.

In an eighth configuration, a plurality of evaporators of the fourth configuration are provided, and a liquid medium flowing out from an outlet end of the first fluid passage of each evaporator is supplied to a liquid reservoir of another evaporator. The liquid medium is sequentially circulated to the first fluid passage of another evaporator.

A ninth configuration is a condensing evaporator in which the evaporator evaporates the liquid medium in the first fluid passage and condenses the fluid in the second fluid passage.

(Operation)

As in the first configuration, the evaporator is formed by introducing a liquid medium to be evaporated from the liquid medium introduction unit to the first fluid passage and a fluid to be exchanged with the liquid medium from the fluid introduction unit to the second fluid passage. Can be operated without immersion in the liquid medium,
The required amount of the liquid medium can be greatly reduced, and the influence of the liquid depth can be reduced, so that it is possible to manufacture a small temperature difference and an energy-saving evaporator in which the temperature difference between the fluids is minimized.

As in the second configuration, the first fluid passage is inclined upward from the liquid medium introduction side to the discharge side, so that bubbles of the vaporized gas easily flow out of the first fluid passage due to its floating force. In addition, the heat transfer coefficient can be enhanced by promoting the flow of the liquid medium.

As in the third configuration, the evaporator of the present invention can be easily manufactured by defining both passages by partitioning them with a partition plate and disposing corrugated heat transfer fins between the partition plates.

As in the fourth configuration, the liquid medium introduction means is formed by the upper and lower multistage liquid reservoirs and / or liquid receivers and the liquid medium supply means. Can be opened, so that the liquid depth of the liquid medium can be set to the depth of each liquid reservoir and / or liquid receiver regardless of the height of the evaporator. Thus, the height of the evaporator can be increased to increase the evaporating capacity, which is advantageous when the installation area of the evaporator is limited.

As in the fifth configuration, the liquid medium supply means can be easily formed by disposing a liquid supply pipe along the liquid reservoir and / or the liquid receiver and communicating the two with the liquid medium supply hole. By adjusting the diameter of the supply hole, the supply amount of the liquid medium to each liquid reservoir and / or liquid receiver can be adjusted.

As in the sixth configuration, a liquid receiver is provided on the outlet side of the first fluid passage of the evaporator having a liquid reservoir on the introduction side of the first fluid passage, and a liquid return flow passage is provided. The liquid medium to be introduced can be self-circulated.

As shown in the seventh configuration, the liquid return flow path can be easily formed by a pipe or a gutter or a flow path provided between the first fluid passages.

According to the eighth configuration, it is possible to sequentially transfer and circulate the liquid medium to another evaporator liquid between the plurality of evaporators.

According to the ninth configuration, by evaporating the liquid medium in the first fluid passage and condensing the fluid in the second fluid passage, it can be used as a condensing evaporator.

According to the sixth to eighth configurations, the amount of liquid medium flowing down the evaporator can be reduced, so that the amount of liquefied oxygen circulated by, for example, a liquefied oxygen pump or a thermosiphon reboiler can be reduced, thereby reducing the cost of recirculation equipment and liquefaction. The power cost of the oxygen pump can be reduced.

〔Example〕

Although the present invention does not limit the fluid in the second fluid passage to nitrogen gas to be condensed, the present invention will be described below with reference to oxygen, a fluid that evaporates in the first fluid passage, and a fluid that condenses in the second fluid passage. An example in which is represented by nitrogen will be described in more detail with reference to the drawings. The liquid flow direction is indicated by a solid arrow, and the gas flow direction is indicated by a dashed arrow.

First, FIGS. 1 to 4 show an embodiment of the present invention, and show a condensing evaporator provided with the above-mentioned liquid reservoir, liquid receiving and liquid returning flow paths.

A condensing evaporator 1 which is a kind of evaporator includes a plurality of first fluid passages (oxygen chambers) 10, 10,.
Are formed alternately in the vertical direction with a predetermined inclination with respect to the horizontal plane, and a liquefied oxygen LO is provided at the lower end 11 of the gradient of the oxygen chamber 10. Liquid reservoirs 30, 30,... As liquid medium introduction means to be introduced into the inside are provided in upper and lower multi-stages,
At the outlet on the upper end side 12 of the gradient, liquid receivers 31, 31,... For receiving unevaporated liquefied oxygen LO flowing out from the end of the oxygen chamber 10 are provided.
Like 30, it is provided in upper and lower stages. In addition, nitrogen chamber 20
At the upper end 21 of the gradient, an inlet header 40 as a fluid introduction means for introducing nitrogen gas GN into the nitrogen chamber 20 is provided, and at the lower end 22 of the gradient, liquefied nitrogen LN condensed in the nitrogen chamber 20 is provided. Is provided.

As shown in FIG. 4, the oxygen chamber 10 and the nitrogen chamber 20
A large number of partition plates 2, 2,... Are formed by being stacked in parallel at a predetermined angle, and between the partition plates 2, 2,. The fins 4, 4,... Are arranged to form a predetermined passage. In the oxygen chamber 10, the fold lines of the corrugated heat transfer fins 4 are arranged in the inclination direction of the oxygen chamber 10, and side bars 3, 3 are provided on both sides of the corrugated heat transfer fins 4.
Are disposed, and the evaporation passage 13 is formed with both sides closed and both ends in the inclined direction opened.

The nitrogen chamber 20 has sidebars around its four circumferences.
3 and 3 are provided to shut off the inside of the nitrogen chamber 20 and the outside atmosphere of the condensing evaporator 1, and open both ends of the side bar 3 on one side of the inclined direction in the inclined direction to the side of the inlet header.
A gas inlet 23 and a liquid outlet 24 are formed to communicate with the outlet 40 and the outlet header 41, respectively. Inside this nitrogen chamber 20,
A condensing passage portion 25 in which the corrugated heat transfer fins 4 are disposed in the center of the gradient in the same direction as the oxygen chamber 10, and the corrugated heat transfer fins 4 are disposed obliquely and introduced from the gas inlet 23. And a gas distribution unit 26 for equally distributing the nitrogen gas GN to the condensing passage portion 25, and similarly, the liquefied nitrogen LN condensed in the condensing passage portion 25 by arranging the corrugated heat transfer fins 4 obliquely. Exit
A liquid collecting part 27 leading to 24 is formed.

This condensing evaporator 1 is manufactured by the above-mentioned partition plate 2, side bar
3, If aluminum is used for the corrugated heat transfer fins 4
It can be easily performed by the same brazing manufacturing technology as the conventional aluminum plate fin type condensing evaporator.

The inclination angle of the oxygen chamber 10 is appropriately selected depending on the length of the evaporation passage 13, the depth of the liquid reservoir 30 to be connected, and the like, and the oxygen chamber 10 can be provided substantially horizontally.
When the liquefied oxygen LO is provided at an ascending gradient with respect to the flow direction, the bubbles of the oxygen gas GO generated by evaporation are more likely to flow out of the oxygen chamber 10 in one direction due to its buoyancy, and are formed by the corrugated heat transfer fins 4. In the narrow passage, the liquefied oxygen LO is entrained in a state where the liquefied oxygen is sandwiched between the bubbles, so that the flow of the liquefied oxygen LO can be promoted to increase the heat transfer coefficient.
Conversely, if the inclination of the oxygen chamber 10 is increased more than necessary, the evaporation passage
13 becomes longer, which inevitably increases the liquid depth, which is not preferable.

In addition, the inclination angle is set so that liquefied oxygen does not exist at the upper end and dryout does not occur. That is, as in the above-described embodiment, by forming the oxygen chamber 10 with an appropriate rising gradient, the bubble of the evaporated oxygen gas GO promotes the flow of the liquefied oxygen LO by its buoyancy, and the gradient of the oxygen chamber 10 is reduced. Since the liquefied oxygen LO flows out from the upper end 12, the liquefied oxygen LO is effectively evaporated and the evaporated oxygen gas GO does not stay, so that the heat exchange efficiency of the condensing evaporator 1 can be improved. Although the driving force for flowing the liquefied oxygen in the oxygen chamber 10 has been mainly described by the floating force of the oxygen gas, the density difference between the gas-liquid mixed phase in the oxygen chamber 10 and the liquefied oxygen in the liquid reservoir 30 also flows. Needless to say, it promotes

Further, the inclination angle of the oxygen chamber 10 needs to be set within a range that does not hinder the flow of the condensed liquefied nitrogen LN in the nitrogen chamber 20 placed in parallel with the oxygen chamber 10. The gradient should be such that the liquefied nitrogen LN condensed in the condensation passage section 25 flows down as quickly as possible and does not stay in the passage.

However, since the nitrogen passage (condensing passage portion 25) can shorten the passage length and greatly increase the total passage cross-sectional area of the nitrogen passage as compared with the conventional vertical passage, the condensed liquid film Since the thickness can be reduced and the amount of condensate (liquefied nitrogen LN) retained in the passage can be reduced, a decrease in heat transfer performance due to the condensate can be prevented.

From this viewpoint, the evaporator of the present invention is an optimal heat exchanger for evaporating the liquid medium in the first fluid passage and flowing condensable gas in the second fluid passage for condensation. However, this does not limit the fluid in the second fluid passage to the condensing gas.

In addition, the vertical interval between the partition plates forming the oxygen chamber 10 should be set to a width suitable for the oxygen gas GO to accompany the liquefied oxygen LO.If the width is too large, the floating force of the oxygen gas GO may increase. It becomes difficult to entrain liquefied oxygen LO. Although a corrugated heat transfer fin is used to form a narrow flow path, it is not limited to only a corrugated heat transfer fin. Also, oxygen chamber
The flow path forming 10 is used to wash out the precipitates by the flow of liquefied oxygen LO so that when hydrocarbons such as acetylene are unintentionally concentrated in the flow paths, they do not adhere to the wall surface. It is preferable to form a circulating flow of liquefied oxygen LO in excess of the amount of evaporation. For this purpose, it is desirable to form a narrow flow passage to promote the liquefied oxygen circulation flow.

That is, the inclination angle, the passage shape, the length, and the like of the oxygen chamber 10 and the nitrogen chamber 20 are set to an optimum state according to various conditions such as the gas-liquid flow rate and the temperature difference in each chamber.

Next, the liquid reservoir 30 has an oxygen chamber in which an opening on one side is
The liquefied oxygen LO supplied to each of the liquid reservoirs 30 is supplied to each of the oxygen chambers 10 by communicating with the lower end side 11 of the gradient of 10, and the upper part is opened to release the pressure to the external atmosphere, and each of the liquid The effect of the liquid pressure of liquefied oxygen LO is reduced by reducing the liquid depth in 30.

A liquid supply pipe 32 for supplying liquefied oxygen LO to each of the liquid reservoirs 30 is provided on one side of the liquid reservoirs 30. This liquid supply pipe 32
A side wall 33 on the side of the liquid reservoir 30 is formed so as to also serve as a side wall of each of the liquid reservoirs 30. Each of the liquid reservoirs 30 and the liquid supply pipe 32 communicate with each other through a liquid supply hole 34 formed in the side wall 33. The liquefied oxygen LO flowing down the liquid supply pipe 32 is supplied from the liquid supply hole 34 into the liquid reservoir 30. The liquid supply holes 34 are formed to have a predetermined diameter depending on the positions of the upper and lower positions of the liquid reservoirs 30 so that a predetermined amount of liquefied oxygen LO can be supplied to each of the liquid reservoirs 30.

In addition, the liquefied oxygen LO contains hydrocarbons as impurities, and is gradually concentrated by evaporation of the liquefied oxygen LO.Therefore, a certain amount is constantly drained to replace the unconcentrated liquefied oxygen LO. It is necessary to adjust the hydrocarbon concentration in the liquefied oxygen LO circulating in the oxygen chamber 10 to a certain value or less. Therefore, in order to drain a certain amount of liquefied oxygen LO and to equalize the amount of liquefied oxygen LO in each
At the upper edge of the side wall 30, a weir 35 is cut out. That is,
By supplying the excess liquefied oxygen LO from the liquid supply pipe 32 to the respective reservoirs 30 by evaporation, and overflowing the excess liquefied oxygen LO from the weir 35, the amount of liquefied oxygen in each reservoir 30 is substantially constant. And a mixture of liquefied oxygen in which hydrocarbons are concentrated and unconcentrated liquefied oxygen to dilute the hydrocarbons in the liquefied oxygen so that the amount of hydrocarbons is maintained at a predetermined value or less. .

One of the liquid receivers 31 is formed substantially in the same manner as the above-mentioned liquid reservoir 30, and one side opening is on the upper end side of the gradient of the oxygen chamber 10 having several upper and lower stages.
12 and receives the liquefied oxygen LO that flows down from the end of each oxygen chamber 10 and separates the oxygen gas GO evaporated in the oxygen chamber 10 from the liquefied oxygen LO from the upper opening of the liquid receiver 31. It is raised above the condensing evaporator 1.

The liquid reservoir 30 and the liquid receiver 31 are provided so as to correspond to the plurality of upper and lower oxygen chambers 10 as one block as described above, and a liquid return flow is provided between the liquid reservoir 30 and the liquid receiver 31. A conduit 36 serving as a path is provided. The conduit 36 is for circulating the liquefied oxygen LO that has been led out into the liquid receiver 31 and returned to the original liquid reservoir 30 by the liquid head of the liquefied oxygen LO, and circulated to the oxygen chamber 10.

Liquefied oxygen introduced into the oxygen chamber 10 thus configured
LO is applied to each liquid reservoir 30 from the liquid supply pipe 32 through a liquid supply hole 34.
And flows into the oxygen chamber 10 from each liquid reservoir 30. The liquefied oxygen LO in each oxygen chamber 10 exchanges heat with the nitrogen gas GN flowing in the adjacent nitrogen chamber 20 via the partition plate 2,
Some of them evaporate and become bubbles of oxygen gas GO. The bubbles of the oxygen gas GO are generated together with the liquefied oxygen LO in the oxygen chamber 10 in the oxygen chamber.
After ascending 10, liquid is separated from liquefied oxygen LO at the outlet end
It rises toward the upper part of the condensation evaporator 1 from between 31 and 31.

On the other hand, the liquefied oxygen LO that has not evaporated in the oxygen chamber 10 is drawn out from the outlet end of the oxygen chamber 10 with the oxygen gas GO and flows down to the liquid receiver 31. The liquefied oxygen LO led out to the liquid receiver 31 of the oxygen chamber 31 flows through the pipe 36 to the original liquid reservoir 30.
And is again introduced from the liquid reservoir 30 into the oxygen chamber 10.
At this time, a part of the liquefied oxygen LO overflows from the weir 35 and flows down below the lower liquid reservoir 30 or the condensing evaporator 1.

That is, the liquefied oxygen LO supplied to the liquid reservoir 30 from the liquid supply pipe 32
Is introduced into the oxygen chamber 10 from the liquid reservoir 30 and reaches the liquid receiver 31 while a part thereof evaporates, and circulates in a path flowing down the pipe 36 from the liquid receiver 31 and returning to the original liquid reservoir 30, The amount evaporated in each oxygen chamber 10,
The amount of liquefied oxygen LO corresponding to the amount of overflow from the weir 35 is supplied from the liquid supply pipe 32 to the liquid reservoir 30 via the liquid supply hole 34.

On the other hand, the nitrogen gas GN introduced into the nitrogen chamber 20 is supplied to the inlet header 40, flows into the gas distributor 26 in the nitrogen chamber 20 from the gas inlet 23, and is rectified by the gas distributor 26. And is introduced into the condensation passage section 25. The liquefied nitrogen LN condensed by the heat exchange with the liquefied oxygen LO in the oxygen chamber 10 in the condensing passage section 25 flows down the condensing passage section 25 due to the gradient of the nitrogen chamber 20, and is collected in the liquid collecting section 27. Then, the liquid is led out from the liquid outlet 24 to the outlet header 41. The non-condensable gas GX such as hydrogen and helium contained in the nitrogen gas GN is supplied to the outlet header 41.
From the purge nozzle 42 provided at the top of the nozzle.

Since the pressure of the liquefied oxygen LO can be released from each of the liquid reservoirs 30 in the condensing evaporator 1 thus formed, the liquid of the liquefied oxygen LO can be compared with a conventional condensing evaporator which is immersed in liquefied oxygen. The pressure rise due to the depth is reduced, the influence of the liquid depth of the liquefied oxygen LO can be reduced, and the temperature difference between the fluids can be reduced accordingly, so that heat exchange is possible even with the minimum temperature difference, The temperature difference is greatly reduced as compared with the temperature difference of the conventional evaporator.

Further, the provision of the liquid receiver 31 and the conduit 36 makes it possible to reduce the amount of liquefied oxygen flowing down the condensation evaporator 1. That is, the amount of liquefied oxygen that overflows from each liquid reservoir 30 and flows below the condensing evaporator 1 may be set to such an extent that hydrocarbons can be prevented from being concentrated in the liquefied oxygen LO in the oxygen chamber 10. Liquefied oxygen supplied from the liquid supply pipe 32
It is sufficient that the amount of LO is slightly larger than the amount of liquefied oxygen evaporating in the condensing evaporator 1. The excess liquefied oxygen LO overflows and flows down, thereby preventing the concentration of hydrocarbons. Therefore, the amount of liquefied oxygen flowing down the condensation evaporator 1 can be reduced. As a result, the amount of liquefied oxygen to be lifted by a liquefied oxygen pump, a thermosiphon reboiler, or the like can be greatly reduced, so that these devices can be downsized, and the power cost thereof can be reduced in addition to equipment costs. The liquefied oxygen pumped by the lifting means can remove hydrocarbons such as acetylene using an adsorber.

On the other hand, the passage in the nitrogen chamber 20 does not increase even if the height of the condensing evaporator 1 is increased.
An increase in the liquid film thickness of LN can be prevented. In addition, by increasing the height of the condensing evaporator 1, the cross-sectional area of the entire passage of the nitrogen chamber can be greatly increased, so that not only the heat transfer performance can be improved and the heat exchange efficiency can be improved, but also When the installation area is limited in combination with the removal of the height restriction on the evaporation side by the liquid reservoir 30, the heat transfer area can be increased by increasing the height of the evaporator, so that the installation area is reduced. be able to.

In the condensing evaporator 1 of the present embodiment, the oxygen chamber 10 and the nitrogen chamber 20 are partitioned by the partition plate 2 to form both chambers in a layered form. It can also be formed by laminating the hollow members thus formed. In addition, the corrugated heat transfer fins 4 are arranged in both chambers to form a passage and the heat transfer area is increased, but both chambers can be formed without such fins. An appropriate heat transfer plate or the like may be provided at an appropriate interval. Further, the passage surface of the oxygen chamber 10 may be a boiling promoting heat transfer surface made of a porous layer or the like, or a condensation promoting heat transfer surface such as flute processing may be formed on the passage surface of the nitrogen chamber 20. When arranging corrugated heat transfer fins or the like in a room, it is desirable to equalize the pressure and the flow rate by using perforated fins or the like.

In addition, as in the present embodiment, by using the liquid reservoirs 30 arranged in upper and lower stages as the liquefied oxygen introducing means of the oxygen chamber 10, the influence of the liquid depth can be reduced as described above, but the height dimension is low. When the influence of the liquid depth can be neglected, such as in a condensing evaporator, the means for introducing liquefied oxygen into the oxygen chamber 10 can be a conduit or a header.

Further, in the present embodiment, the upper and lower liquid reservoirs 30 and the liquid receivers 31 are provided so as to correspond to each other. However, the size of each of the liquid reservoirs 30 and the liquid receivers 31 is changed in the vertical direction, and The receivers 31 may be arranged for different oxygen chamber blocks, respectively, or a liquid return flow path (pipe 36) from the liquid receiver 31 may be connected to a lower stage than the corresponding liquid reservoir 30. Further, the supply of the liquefied oxygen LO to each of the liquid reservoirs 30 may be connected by a flow path that allows each of the liquid reservoirs 30 or the liquid receiver 31 and the liquid supply pipe 32 to communicate with each other, without providing the liquid supply pipe 32. The liquefied oxygen LO is supplied only to the uppermost liquid reservoir, and the lower liquid reservoir 30 or liquid receiver 31 is supplied from the liquid reservoir 30 or liquid receiver 31 by the weir 35 or the overflow pipe or the liquid return flow path.
Alternatively, a structure in which the liquefied oxygen LO flows down sequentially may be used.

Further, the supply amount of the liquefied oxygen LO to each liquid reservoir 30 is adjusted by providing a flow rate adjusting mechanism, or using an overflow pipe instead of the diameter of the liquid supply hole 34, the position and size of the weir 35, or the weir. In this case, it can be carried out by adjusting the diameter, mounting position, and the like of the overflow pipe.

Further, it can be formed without providing the liquid receiver 31 and the liquid return flow path. At this time, the liquefied oxygen that has flowed below the condensing evaporator 1 can be lifted and circulated by a suitable lifting means such as a liquefied oxygen pump, and the liquefied oxygen is led out of the system without being lifted. Liquefied oxygen and / or oxygen gas. Alternatively, in the case of a device that collects a large amount of liquefied oxygen as a product,
It is also possible to adjust the amount of liquefied oxygen that flows down without providing a liquid return channel or the like, or by providing a part in the vertical direction.

If there is no problem even if the fluid to be evaporated is completely evaporated, there is no problem even if the fluid is formed without providing the liquid receiving and returning channels, the overflow weir of the liquid reservoir, and the like.

Further, the liquid return flow path can be formed by the conduit 36 as described above, but can also be formed by a gutter-shaped flow path having an open upper part.

FIG. 5 and FIG. 6 show another embodiment of the liquid return flow path, in which nitrogen is disposed between the oxygen chambers 10 and 10 so as to correspond to the liquid reservoirs 30 and the liquid receivers 31, respectively. A part of the chamber 20 is replaced with a liquid return chamber 37 serving as a liquid return flow path. In the following description, the condensation evaporator 1 shown in FIGS. 1 to 4 will be described.
The same elements as those described above are denoted by the same reference numerals, and detailed description thereof will be omitted.

As shown in the figure, the condensing evaporator 1 has a passage adjacent to the upper part of the oxygen chamber 10 connected to the bottoms of the liquid reservoirs 30 and the liquid receiver 31, that is, a gradient of the passage which was the nitrogen chamber in the above embodiment. The upper and lower ends are opened similarly to the oxygen chamber 10 to communicate the liquid reservoir 30 with the liquid receiver 31, and a liquid return chamber 37 for returning the liquefied oxygen LO in the liquid receiver 31 to the liquid reservoir 30.

Since the upper and lower portions of the liquid return chamber 37 are sandwiched between the oxygen chambers 10, 10, the liquid return chamber 37 does not contact the nitrogen chamber 20, so that the amount of heat exchange with the nitrogen gas GN is small and the amount of liquefied oxygen LO evaporated is also small. Therefore, as described above, the liquefied oxygen LO that has not evaporated and flows out of the oxygen chamber 10 to the liquid receiver 31 is returned to the liquid reservoir 30 by flowing down the liquid return chamber 37 due to the difference between the liquid head of the liquid receiver 31 and the liquid reservoir 30. The oxygen chamber 10 can be circulated in the same manner as in the above embodiment. It should be noted that it is desirable not to dispose any liquid resistance inside the liquid return chamber 37.

The liquid return chamber 37 can be integrally formed simultaneously with the oxygen chamber 10 and the nitrogen chamber 20 only by changing the arrangement of the side bar 3 and the corrugated heat transfer fins 4 in the process of manufacturing the condensation evaporator 1. Therefore, the manufacturing process can be simplified as compared with the case where piping is provided outside the condensing evaporator 1, and the handling property during transportation and assembly is excellent.

Next, FIG. 7 shows a case where a plurality of condensing evaporators 1 having the same configuration as that shown in the above embodiment are provided, and the liquid receiver 31 and the liquid reservoir 30 of the adjacent condensing evaporators 1, 1 are integrated. 1 shows an embodiment of the present invention.

That is, the liquefied oxygen LO flowing down from the oxygen chamber 10 of one condensing evaporator 1 flows down to the liquid receiving and liquid reservoir 38 provided between the condensing evaporator 1 and the condensing evaporator 1 and is adjacent to the condensing evaporator 1. Is introduced into the oxygen chamber 10 of the condensing evaporator 1. Hereinafter, the liquefied oxygen LO that has not been evaporated in the oxygen chamber 10 of each condensing evaporator 1 sequentially passes through the liquid receiving / reservoir 38 to the oxygen chamber of the condensing evaporator 1 on the downstream side.
10 will be introduced. Liquefied oxygen LO is supplied to the respective liquid receiving and liquid reservoirs 38 from the liquid supply pipes 32, respectively, to prevent hydrocarbon concentration.

Further, a plurality of condensing evaporators 1 can be arranged circumferentially to circulate liquefied oxygen LO endlessly.
May be provided with a liquid reservoir 30 and a liquid receiver 31, respectively, and connected by a liquid supply flow path such as a pipeline or a gutter. Two condensing evaporators
Install the reservoir 3 so that the inclination of both passages 1 and 1 are opposite.
0 and the liquid receiver 31 are arranged so as to correspond to each other, and two condensing evaporators
Liquefied oxygen LO can be circulated between 1,1.

FIGS. 8 and 9 show an embodiment in which the condensing evaporator 1 of the present invention is applied to the condensing evaporator of a double rectification column 50 of an air liquefaction / separation apparatus.

In the present embodiment, four condensing evaporators 1 and 1 are arranged circumferentially in the lower space of the upper tower 51. This condensation evaporator 1
Has a structure in which the liquid return chamber 37 shown in FIGS. 5 and 6 is provided, and a manifold pipe 53 for supplying nitrogen gas, which is provided from the lower tower 52 to the center of the upper tower 51, is connected. As the center, the liquid reservoir 30 is arranged facing the manifold tube 53 side.

The liquefied oxygen LO flowing down from the rectification stage 54 of the upper tower 51 flows down from the liquefied oxygen receiver 55 to the liquefied oxygen reservoir 57 via the pipe 56, and further flows down the liquid supply pipe 32 from the liquid supply hole 34. Each reservoir
Distributed to 30. As described above, the liquefied oxygen LO in each liquid reservoir 30 is introduced into the oxygen chamber 10 and partially evaporates, as a gas-liquid mixed flow, rises in the oxygen chamber 10 and is not evaporated at the outlet end. And rises separately from the liquefied oxygen LO, part of which is led out of the nozzle 58 as product oxygen gas GO, and the remainder becomes the rising gas in the upper tower 51. Also, the liquefied oxygen LO that has not evaporated flows down from the liquid receiver 31 through the liquid return chamber 37, returns to the original liquid reservoir 30, mixes with the liquefied oxygen LO supplied from the liquid supply pipe 32, and returns to the oxygen chamber.
Flows into 10.

A part of the liquefied oxygen LO in the liquid reservoir 30 flows down from the weir or the overflow pipe to the bottom of the upper tower 51 as liquefied oxygen for preventing hydrocarbon concentration. The liquefied oxygen LO that has flowed down to the bottom is taken out of the nozzle 59, is lifted into the liquefied oxygen reservoir 57 by means of a liquefied oxygen pump or a lifting means 60 such as a thermosiphon reboiler, and is concentrated in the liquefied oxygen LO. The hydrocarbons are removed by the adsorption device 61.

On the other hand, the nitrogen gas GN in the upper part of the lower tower 52 rises up the manifold pipe 53, is supplied from the connecting pipe 62 to the inlet header 40 of each of the condensation evaporators 1, 1, and is introduced into each nitrogen chamber 20 as described above. . The liquefied nitrogen LN condensed in the nitrogen chamber 20 is led out of the nozzle 63 via the outlet header 41.

Thus, by using the condensation evaporator 1 of the present invention for heat exchange between the evaporation of the liquefied oxygen LO and the condensation of the nitrogen gas GN in the air liquefaction / separation apparatus, the pressure of the liquefied oxygen LO is reduced
Since it is opened at 30, the pressure rise (boiling point rise) due to the liquid depth of liquefied oxygen LO is smaller than that of a condensing evaporator that is immersed in liquefied oxygen, which was conventionally 2 meters deep. The effect of the liquefied oxygen LO due to the liquid depth can be almost eliminated, and the temperature difference between the fluids can be reduced by 1 to 2 times.
℃ to a minimum of 0.3 ℃.

In addition, since the device can be operated without storing a large amount of liquefied oxygen LO in the lower portion of the upper tower 51, problems in starting time of the device and security can be easily solved.

Furthermore, since the effect of the liquid film of the condensed liquefied nitrogen LN is reduced, the heat exchange efficiency is improved, and the influence of the liquid depth of the liquefied oxygen LO is eliminated. It becomes possible to manufacture a condensation evaporator in which the temperature difference is reduced to the limit. As a result, the condensation temperature of the nitrogen gas, that is, the pressure of the nitrogen gas GN that determines this temperature can be reduced, so that the operating pressure of the lower tower 52 can be lowered and the power cost of the raw material air compressor can be reduced. This makes it possible to reduce the power consumption rate of product gas and the like.

In addition, since there is almost no influence of the liquid pressure of the liquefied oxygen LO, there is no limitation on the shape of the condensing evaporator 1 in the height direction, and the processing capacity can be greatly increased by increasing the height of the condensing evaporator. This makes it possible to reduce the installation area limitation, facilitate the incorporation into a rectification tower for a large-sized air separation device, and make it possible to manufacture the rectification tower in a vertically integrated structure. Also,
The cost of recirculating equipment such as a liquefied oxygen pump and the cost of power can be significantly reduced.

In addition, the evaporator of the present invention is not limited to evaporation and condensation by heat exchange between liquefied oxygen and nitrogen gas in air liquefaction separation, but also to evaporation of other liquid medium and heat exchange with a fluid (not limited to condensed fluid). It is needless to say that the same operation and effect can be obtained when used, and that it can be applied as an energy-saving evaporator to a small temperature difference evaporator in a process other than the air separation device.

〔The invention's effect〕

As described above, the evaporator according to the present invention includes the first and second evaporators.
And the liquid medium to be evaporated is introduced from one end of the first fluid path, so that the evaporator is operated with a small amount of liquid medium without being immersed in the liquid medium. As a result, the startup time can be shortened and the influence of the liquid depth can be reduced. Further, when the influence of the liquid pressure of the liquid medium and the fluid in the second fluid passage are condensed fluids, there is almost no influence of the liquid film, so that the liquid medium and the fluid can be efficiently heat-exchanged, The heat exchange efficiency of the evaporator is improved, and the temperature difference between the fluids can be minimized. In addition, there is no limitation on the shape of the evaporator in the height direction, and by increasing the height of the evaporator, the processing capacity can be greatly increased, and the installation area can be reduced. Further, the evaporator of the present invention can be easily manufactured by the same means as the conventional one without using any special process or member by using a general partition plate and corrugated heat transfer fins.

Further, by using a liquid reservoir having an open top as the liquid medium introduction means of the first fluid passage, the pressure can be released at each liquid reservoir portion, so that the liquid depth of the liquid medium can be adjusted regardless of the height of the evaporator. It can be the depth of the reservoir. In particular, a liquid supply pipe is arranged along the liquid reservoir, and the liquid medium supply means can be easily formed by communicating with the liquid medium supply hole. The supply amount of the liquid medium can be adjusted.

Further, by providing a liquid receiver and a liquid return flow path in the first fluid passage and circulating the liquid medium, the supply amount of the liquid medium can be reduced. The liquid return flow path can be easily formed by a pipe or a gutter or a flow path provided between the first fluid passages. In particular, when a liquid return flow path is provided between the first fluid passages, a liquid return flow path can be formed simultaneously with the formation of both paths of the evaporator, so that piping work and the like can be omitted, and assembly into a rectification tower or the like can be performed. The mounting workability can also be improved. Further, the liquid medium can be circulated between the plurality of evaporators by connecting the liquid receiver and the liquid reservoir of the plurality of evaporators with a liquid supply flow path such as a pipe or a gutter.

Therefore, the evaporator of the present invention is particularly suitable for a condensing evaporator of a large-scale air liquefaction / separation device having a large throughput, and can reduce the size of the entire device and reduce the operating power cost, thereby reducing the power consumption unit of the product. Can be reduced.

[Brief description of the drawings]

1 to 4 show an embodiment of an evaporator according to the present invention. FIG. 1 is a partially cutaway front view of a condensing evaporator, FIG. FIG. 4 is a partially cutaway perspective view, FIG. 4 is an exploded perspective view of the same main part, and FIGS.
FIG. 5 shows another embodiment of the liquid return flow path. FIG. 5 is a partially cutaway front view of the condensing evaporator, FIG. 6 is also a partially cutout right side view, and FIG. Partially cutaway front view showing an embodiment in which the liquid receiver and the liquid reservoir of the container are connected by a liquid supply flow path,
8 and 9 show an embodiment applied to a double rectification column. FIG. 8 is a cross-sectional front view of a main part of the double rectification column, and FIG. 9 is a cross-sectional plan view of the same. 1 ... condensing evaporator, 2 ... partition plate, 4 ... corrugated heat transfer fin, 10 ... first fluid passage (oxygen chamber), 20 ... second fluid passage (nitrogen chamber), 30 ... liquid reservoir , 31 ... liquid receiver, 32 ... liquid supply pipe, 34 ... liquid supply hole, 36 ... conduit, 37 ... liquid return chamber, 40
…… Inlet header, 41 …… Outlet header, 50 …… Double rectification tower, 51 …… Upper tower, 52 …… Lower tower, GN …… Nitrogen gas, GO
…… Oxygen gas, LN …… Liquid nitrogen, LO …… Liquid oxygen

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-60-17601 (JP, A) JP-A-63-267877 (JP, A) JP-A-60-253782 (JP, A) JP-A-2- 97885 (JP, A) JP-A-2-23985 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) F25J 5/00 F28D 9/00-9/04 F28F 3/00 311 F28F 3/08 311

Claims (9)

(57) [Claims] In an evaporator for performing heat exchange between a liquid medium in a first fluid passage and a fluid in a second fluid passage, a plurality of first fluid passages and second fluid passages are mainly laminated alternately in the vertical direction. ,
One end of the first fluid passage is provided with a liquid medium introduction unit for introducing the liquid medium into the first fluid passage, and the other end is opened to serve as a liquid medium outlet. An evaporator characterized in that a fluid introduction means for introducing the fluid into the second fluid passage is provided on a side of the evaporator, and the other end is an outlet. 2. The evaporator according to claim 1, wherein the first fluid passage has a rising gradient from a liquid medium introduction side to a discharge side. 3. The method according to claim 1, wherein the first fluid passage and the second fluid passage are defined by partitions provided between the respective passages, and corrugated heat transfer fins are provided between the partitions. The evaporator according to claim 1, wherein 4. The liquid medium introduction means includes a plurality of liquid reservoirs and / or liquid receivers, which are communicated with a liquid medium introduction end of the first fluid passage and are disposed in a plurality of upper and lower stages. 2. An evaporator according to claim 1, further comprising a liquid medium supply means for supplying a liquid medium to the liquid receiver, wherein the liquid reservoir and / or the liquid receiver are open at the top. 5. The liquid medium supply means includes: a liquid supply pipe disposed along the liquid reservoir and / or the liquid receiver arranged in the upper and lower multi-stages; and a side wall of the liquid reservoir and / or the liquid receiver. 5. The evaporator according to claim 4, further comprising a liquid medium supply hole provided to communicate the liquid supply pipe with each of the liquid reservoirs and / or the liquid receivers. 6. The first fluid passage communicates with an outlet end of the first fluid passage,
A plurality of upper and lower liquid receivers, each having an open upper portion for receiving a liquid medium flowing out from the outlet end of the first fluid passage, and a liquid return flow path for returning the liquid medium flowing out to the liquid receiver to the liquid reservoir; The evaporator according to claim 4, further comprising: 7. The method according to claim 7, wherein the liquid return flow path is formed by a pipe or a gutter, or a flow path provided between the first fluid passages so as not to be adjacent to the second fluid passage. The evaporator according to claim 6, characterized in that: 8. An evaporator according to claim 4, wherein a plurality of evaporators are provided, and a liquid medium flowing out from an outlet end of a first fluid passage of each evaporator is supplied to a liquid reservoir of another evaporator. An evaporator characterized in that a liquid medium is sequentially circulated to a first fluid passage of another evaporator. 9. The evaporator according to claim 1, wherein the evaporator evaporates the liquid medium in the first fluid passage and condenses the fluid in the second fluid passage.