JPH0789010B2 - Condensation evaporator and its operating method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention allows heat exchange between a liquid medium in a first fluid chamber and a fluid in a second fluid chamber to evaporate and vaporize the liquid medium and condense and liquefy a gas fluid. And a method of operating the same, in particular, in a condensing evaporator used in an air liquefaction separation device, a liquid medium introduced into a first fluid chamber, that is, liquefied oxygen introduced into an oxygen chamber, is efficiently boiled with a small amount. The present invention relates to a condensing evaporator suitable for evaporating and efficiently condensing and liquefying a gas fluid introduced into a second fluid chamber, that is, a nitrogen gas introduced into a nitrogen chamber, and an operating method thereof.

[Conventional technology]

Condensation evaporator used in the double rectification column of the air liquefaction separation device, as shown in JP-A-56-56592,
A so-called plate fin heat exchanger in which the vertical direction is partitioned by a number of parallel partition plates, and two chambers, an oxygen chamber that is the first fluid chamber and a nitrogen chamber that is the second fluid chamber, are alternately stacked next to each other. What is used is often used.

9 and 10 show a conventional plate fin type condensation evaporator of this type. FIG. 9 shows an oxygen chamber of the condensation evaporator, and FIG. 10 also shows a nitrogen chamber. . In each of the following figures, the solid line arrow indicates the liquid flow direction, and the chain line arrow indicates the gas flow direction.

The oxygen chamber 2 of the condensing evaporator 1 is provided with a heat transfer plate inside to form a large number of vertical evaporation passages 3, 3, and the upper and lower end portions of the evaporation passage 3 are opened to form a lower end. Liquefied oxygen
An LO inlet 4 is provided, and an upper end portion thereof is an outlet 5 for a mixed flow of oxygen gas GO and liquefied oxygen LO. The oxygen chamber 2 is filled with liquefied oxygen LO by immersing the condensation evaporator 1 in the liquefied oxygen LO accumulated in the bottom space of the upper tower 6, and the liquefied oxygen LO in the oxygen chamber 2 is adjacent to the liquefied oxygen LO. Nitrogen gas in the nitrogen chamber 7 GN
And heat is exchanged, and a part thereof evaporates to form bubbles of oxygen gas GO and rises in the evaporation passage 3. The liquefied oxygen LO forms a circulation flow inside and outside the condenser-evaporator 1 due to the density difference between the gas-liquid mixed phase of the liquefied oxygen LO in the oxygen chamber and the vaporized oxygen gas GO and the liquefied oxygen LO outside the oxygen chamber. . In addition, some of the liquefied oxygen LO and oxygen gas GO are outsourced as products.

On the other hand, in the nitrogen chamber 7, a large number of vertical condensing channels 8, 8 are formed in a chamber in which each end of the four circumferences is sealed.
The upper and lower ends of the above are connected to the lower tower 13 via headers 9 and 10 and pipes 11 and 12 provided above and below one end of the nitrogen chamber 7, respectively. This nitrogen chamber 7 includes a pipe 11 and an upper header 9
Nitrogen gas GN in the upper part of the lower tower 13 is introduced into the condensing flow path 8 as a downward flow via, and the liquefied nitrogen LN condensed in the condensing flow path 8 is led out from the lower header 10 and the pipe 12. Further, the non-condensable gas GX in the nitrogen gas GN is led out from the purge nozzle 10a provided on the upper part of the lower header 10.

[Problems to be Solved by the Invention]

However, since the conventional condensing evaporator 1 is used by immersing the whole in the liquefied oxygen LO in the bottom space of the upper tower 6, the condensing evaporator is required to store a large amount of liquefied oxygen LO in the space. I couldn't get 1 to work. As a result, it takes a long time to start up the device, and the amount of oxygen released at the time of stoppage is large, resulting in loss of power costs and the like. In addition, there are major security issues in case of an emergency.

Furthermore, since the boiling point of the liquefied oxygen LO in the lower part of the bottom space of the upper tower 6 increases due to the liquid depth of the liquefied oxygen LO, the liquefied oxygen LO flowing from the lower part of the oxygen chamber 2 into the evaporation passage 3 is in a supercooled state. . Therefore, in the lower part of the oxygen chamber 2, the liquefied oxygen LO rising in the evaporation passage 3 must be heated to the boiling start temperature by convective heat transfer with low heat transfer efficiency, and the heat transfer efficiency of the flow path 3 is lowered. Was there.

In order to reduce the influence of the liquid depth of this liquefied oxygen, JP-A-60
-17601 gazette and the like propose a liquid-medium-flow-type condensing evaporator that evaporates liquefied oxygen in an oxygen chamber while flowing it down, but liquefied oxygen for circulating the liquefied oxygen after flowing down to the upper part of the condensing evaporator. Needs additional equipment such as pumps.
Further, Japanese Patent Laid-Open No. 62-213698 and the like propose means for changing the characteristics of the heat transfer surface in the vertical direction, controlling the liquid pressure of liquefied oxygen, and the like. It has been desired to improve the heat exchange efficiency of the evaporator.

Further, in the nitrogen chamber 7 on the condensing side, the condensing channel 8 is formed in the vertical direction, and the nitrogen gas GN flows down while condensing, so that the amount of liquefied nitrogen increases in the lower part of the channel 8 and the thick liquid Since it forms a film and covers the surface of the heat transfer surface, it becomes a heat resistance layer and reduces heat transfer performance.

Therefore, the present invention reduces the required amount of liquefied oxygen (liquid medium) on the oxygen chamber (first fluid chamber) side and transfers heat by condensate of nitrogen gas (gas fluid) on the nitrogen chamber (second fluid chamber) side. An object of the present invention is to provide a condensing evaporator in which performance deterioration is eliminated and a heat transfer region of liquefied oxygen is divided into two parts to reduce the influence of liquid depth, and an operating method thereof.

[Means for Solving the Problems]

In order to achieve the above-mentioned object, the condensing evaporator of the present invention has a plurality of vertical partition plates alternately forming a plurality of first fluid chambers and second fluid chambers, and a liquid medium of the first fluid chambers. And a condensing evaporator that performs heat exchange with the gas fluid in the second fluid chamber, a liquid medium reservoir is provided above the condensing evaporator, and the liquid medium is provided in the first fluid chamber near its boiling start point. A downflow heat transfer area for heating up to a boiling start point and an upflow heat transfer area for heating the liquid medium above the boiling start point are provided, and the downflow heat transfer area and the upflow heat transfer area are communicated in the lower part of the first fluid chamber. In addition, the upper portions of both regions are communicated with the liquid medium reservoir, and the heat transfer area of the downward flow heat transfer region of the first fluid chamber is such that the liquid medium heated while flowing down the region is the lower end portion of the region. And is set so that the saturation temperature corresponds to the lower end pressure. In addition, the plurality of first fluid chambers have a part of the chambers as a liquid medium heating greenhouse serving as a downflow heat transfer region, and the remaining chambers serving as a liquid medium evaporation chamber serving as an upflow heat transfer region, and both chambers. The lower end of each of them is communicated with each other by a communication passage, and the first fluid chamber is formed into at least three flow passages in the width direction by at least two partition bars arranged from the upper end of the chamber to the vicinity of the lower end. The flow path at the center is defined as a downflow heat transfer area, and the flow paths at both sides are defined as upflow heat transfer areas. And, a condensate flow down passage having an open lower end corresponding to the downward flow heat transfer region of the first fluid chamber is provided in the center in the width direction of the second fluid chamber, and the condensate flow passage is condensed in the condensate flow down passage. Opened the liquid outlet,
The second fluid chamber has at least one side end opened to form a gas introduction port for introducing a gas fluid, and a condensing liquid having a downward gradient with respect to the horizontal direction from the gas introduction port to the condensate derivation port. A flow path is formed, and the second fluid chamber closes the upper end and opens both side ends or both side ends and the lower end, and one side end of the opening serves as a gas inlet and the other side. The opening of the end portion or the other side end portion and the lower end portion is used as a condensate outlet, and that a liquid draining portion is provided in a part of the condensate outlet of the condensing passage of the second fluid chamber. The heat transfer body such as a corrugation fin is disposed inside the first fluid chamber, and the surface of the upflow heat transfer region of the first fluid chamber is a boiling promotion nuclear heat transfer surface. Forming the first fluid chamber from the upper end to the lower end of the chamber 2 by the partition rods disposed over near
Partitioning and forming one flow path, one flow path as a downflow heat transfer area, and the other flow path as an upflow heat transfer area, and the downflow heat transfer area of the first fluid chamber condensing the second fluid chamber. It includes disposing in the vicinity of the liquid outlet and forming the condensing channel of the second fluid chamber with corrugation fins.

And the operation method of the condensation evaporator of the present invention is, firstly,
In operating the condensing evaporator configured as described above, the liquid medium being introduced from the liquid medium reservoir and flowing down the downflow heat transfer region of the first fluid chamber, the gas fluid of the adjacent second fluid chamber is used. The liquid medium is heated to a temperature near the boiling start point, and then introduced into the upflow heat transfer region to evaporate the liquid medium by heating the liquid medium to a temperature above the boiling start point of the liquid medium, and the unevaporated liquid The medium is circulated and introduced from the liquid medium reservoir into the downward flow heat transfer region, and in particular, the liquid medium flowing down the downward flow heat transfer region of the first fluid chamber has a lower end portion at a lower end portion of the area. It is characterized in that the liquid medium supply amount is adjusted so that the saturation temperature corresponds to the pressure. Furthermore, as the second driving method,
In controlling the condensing / evaporating capacity of the condensing evaporator during the operation of the condensing evaporator, a condensate reservoir for accumulating the condensate condensing in the second fluid chamber and flowing down is provided below the condensing evaporator. The amount of the condensate discharged from the liquid reservoir is adjusted to change the amount of the lower part of the second fluid chamber immersed in the condensate, or instead of the condensate reservoir, the second part of the condensate evaporator is provided at the lower part. It is characterized in that a header for condensing the condensate that condenses in the fluid chamber and flows down is connected in series, and the amount of the condensate discharged from the header is adjusted to change the amount of the condensate in the second fluid chamber.

[Work]

By configuring the condensing evaporator as described above, the liquid medium is stored in the upper liquid medium reservoir without immersing the condensing evaporator in the liquid medium, and the liquid medium is transferred from the liquid medium reservoir to the first fluid chamber. Since it can be operated simply by introducing it, the condenser-evaporator can be operated with a smaller amount of liquid medium than before. Furthermore, since the condensing flow path of the second fluid chamber is formed in a downward gradient from the gas introduction port formed at one end to the condensate derivation port, the gas fluid can be introduced substantially evenly in the vertical direction of the second fluid chamber, The liquid medium in the first fluid chamber can be efficiently heated.

Further, as the most important action of the present invention, since the liquid medium is heated in the downward flow heat transfer region and introduced into the upward flow heat transfer region, the influence of the liquid depth is reduced and boiling evaporation is immediately started in the upward flow heat transfer region. Therefore, the height direction of the condensation evaporator can be effectively used as a heat transfer area. Further, as shown in the operating method of the present invention, by adjusting the amount of condensed liquid in the second fluid chamber, the area of the heat transfer surface in contact with the gas fluid in the second fluid chamber can be adjusted. It is possible to control the amount of evaporation of the liquid medium heated by the gas fluid as well as the amount of condensation. Therefore, it is possible to control so that the above-mentioned action is accurately obtained.

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to the drawings with respect to an example in which the first fluid chamber is an oxygen chamber, the second fluid chamber is a nitrogen chamber, the evaporating liquid medium is oxygen, and the condensing gas fluid is nitrogen. . The same elements as those of the conventional example are designated by the same reference numerals, and detailed description thereof will be omitted.

First, FIGS. 1 and 2 show a first embodiment of the condensing evaporator of the present invention. FIG. 1 shows an oxygen chamber part of the condensing evaporator, and FIG. 2 shows a nitrogen chamber part of the same. There is. It should be noted that, in this embodiment, it is possible to carry out only the nitrogen chamber and the conventional nitrogen chamber in combination.

The condensing evaporator 20 is arranged in a space 21 formed between the upper tower 6 and the lower tower 13 of the double rectification tower, and has an oxygen chamber 22.
The left and right ends and the lower end of each chamber partitioned by the vertical partition plate are closed by side bars 23, 23, and substantially the entire upper end is opened, and the upper tower is located above the opening. A liquid medium reservoir 24 formed at the bottom of the 6 is continuously provided.

The inside of the oxygen chamber 22 is divided into three flow passages in the width direction by two partition rods 25, 25 provided from the upper end portion to the vicinity of the lower end portion. The downflow heat transfer area 26 is used, and the two flow paths on both sides are connected to the upflow heat transfer areas 27, 2
7 The downflow heat transfer area 26 and the upflow heat transfer area 2
The 7 is communicated with the communication passages 28, 28 formed between the lower end of the partition rod 25 below the oxygen chamber 22 and the side bar 23. A heat transfer member 29 such as a corrugation fin is arranged in each of the downflow heat transfer area 26, the upflow heat transfer area 27, and the communication passage 28.

The liquefied oxygen LO rectified in the upper tower 6 is
Is introduced into the liquid medium reservoir 24 by the nitrogen gas GN in the nitrogen chamber 31 described later while being flowed down in the downward flow heat transfer region 26 in the oxygen chamber 22, and is introduced into the upward flow heat transfer region 27 via the communication passage 28. To be done. Liquefied oxygen LO is transferred to the upflow heat transfer area 27 in the nitrogen chamber 31.
Is heated by the nitrogen gas GN, and part of it is evaporated to become oxygen gas GO, which rises as a gas-liquid mixed flow. Liquefied oxygen LO and oxygen gas rising from the upflow heat transfer area 27 to the liquid medium reservoir 24
The gas-liquid mixed flow of GO is separated in the liquid medium reservoir 24, part of the oxygen gas GO is discharged as a product, and the rest becomes the ascending gas of the upper tower 6. Further, a part of the liquefied oxygen LO is discharged as a product, and most of the liquefied oxygen LO again flows into the downflow heat transfer region 26 and circulates in the oxygen chamber 22. Further, a small amount of liquefied oxygen LO is led out from a header 32 that is connected to the lower part of the oxygen chamber 22 in order to prevent the concentration of acetylene in the oxygen chamber 22.

While circulating the liquefied oxygen LO in the oxygen chamber 22 in this way,
By forming a part of it to evaporate, the liquefied oxygen LO required to function the condensing evaporator 20 may be the amount filling the oxygen chamber 22 and the predetermined amount stored in the liquid medium reservoir 24. As in the conventional case, the condensation evaporator 20 can be operated in a much smaller amount than the amount in which the entire condensation evaporator 20 is immersed. As a result, the start-up time of the air separation device can be shortened, the amount of refrigerant discharged when the device is stopped can be reduced, and security problems can be easily solved. Further, since the liquefied oxygen LO circulates in the oxygen chamber 22 due to its own density difference, pumping equipment such as a pump and a thermosiphon reboiler and other incidental equipment are not required, and new equipment costs and power costs are required. Nothing.

The circulation of the liquefied oxygen LO in the oxygen chamber 22 is performed in the downward flow heat transfer area.
It occurs due to the difference in the apparent density of the gas-liquid mixed phase consisting of liquefied oxygen LO and oxygen gas GO in the upflow heat transfer region 27 with respect to the density of liquefied oxygen LO in 26.
[Head difference between downflow heat transfer area 26 and upflow heat transfer area 27-
The larger the value of [liquid phase flow pressure loss in the downflow heat transfer area 26 and the upflow heat transfer area 27-gas-liquid two-phase flow pressure drop in the upflow heat transfer area 27], the larger. Therefore, in order to increase the circulation amount of the liquefied oxygen LO, it is necessary to increase the head difference in both flows to reduce the pressure loss. In particular, since the pressure drop of the gas-liquid two-phase flow in the upflow heat transfer area 27 has a great influence, it is necessary to select the heat transfer body 29 arranged in the upflow heat transfer area 27 that has a small pressure loss coefficient. From this, by arranging a heat transfer body such as a corrugation fin in the upflow heat transfer area 27 and forming a boiling promotion nucleus on the primary transfer surface (surface of the partition plate) of the upflow heat transfer area 27, liquefaction is achieved. It is possible to promote boiling evaporation of oxygen LO and reduce flow pressure loss. The boiling promoting nuclei can be formed by sintering powder metal, thermal spraying, or machining a reentrant cavity.

Further, the heat transfer area of the downflow heat transfer area 26 can heat the liquefied oxygen LO flowing down the area 26 to a temperature lower than the saturation temperature or the boiling start temperature corresponding to the lower pressure in the lower part of the area 26. It is preferable to set as follows. This setting is set appropriately according to various conditions such as the ratio of the downflow heat transfer area 26 to the upflow heat transfer area 27, the flow rate of liquefied oxygen LO, the temperature difference from the nitrogen gas GN in the adjacent chamber, and the heat transfer efficiency. The heat area can be easily adjusted by changing the installation width of the heat transfer member 29. Further, during the operation, the flow rate of the liquefied oxygen LO can be adjusted to change the residence time in the downflow heat transfer region 26 to adjust the temperature.

In this way, by introducing the liquefied oxygen LO into the upflow heat transfer region 27 by warming the liquefied oxygen LO to near the saturation temperature in the downflow heat transfer region 26, the temperature distribution in the condenser evaporator 20 can be significantly improved. The condenser evaporator capacity can be improved.

On the other hand, as shown in FIG. 2, the nitrogen chamber 31, which is disposed adjacent to the oxygen chamber 22 via a partition plate, closes the entire upper end portion facing the liquid medium reservoir 24 with a side bar 33, and Heat transfer members 34, 34 such as corrugation fins having both ends opened in a portion of the oxygen chamber 22 adjacent to the upflow heat transfer region 27.
Are provided to form a large number of condensing flow paths 35, 35, and a condensate descending path 36 is formed in a portion adjacent to the downflow heat transfer area 26.

The condensation channel 35 is liquefied nitrogen condensed in the condensation channel 35.
In order to allow LN to flow down from the condensing flow path 35, from the gas inlet 37 opened at the side end of the nitrogen chamber 31 to the condensate outlet 38 opened to the condensate flow-down passage 36 in the horizontal direction as appropriate. There is a gentle downhill slope. Further, the condensate outlet 38 that opens to the condensate lower passage 36 has its opening end formed stepwise so that a part of the condensate outlet 38 protrudes into the condensate lower passage 36, and the upper surface of the step serves as the liquid draining portions 39, 39. The liquid draining section 39 guides the liquefied nitrogen LN flowing down from the condensate outlet 38 of the upper condensing flow path 35 to the condensate flow-down passage 36, and the liquefied nitrogen flowing down from above.
LN flows down along the condensate outlet port 38, and the condensate flow path 35 below
It is prevented that the condensate outlet 38 is closed with a liquid film.

The nitrogen chamber 31 is connected to the upper part of the lower tower 13 by connecting gas inlet headers 40, 40 to the gas inlets 37, 37 at both ends, and side bars 41, 41 on both sides of the lower end. A condensate outlet header 42 is provided continuously at the opening of the condensate flow-down passage 36 in the central portion.

Nitrogen gas GN rectified in the lower tower 13 is a pipe for gas rise
43 through the gas inlet header 40 to the condensation channel 35 of the nitrogen chamber 31
Will be introduced to. The connection position of the piping 43 to the inlet header 40 is not limited to the lower portion of the inlet header 40 as illustrated, but may be the upper portion or the middle portion of the inlet header 40,
It can be appropriately set according to various conditions.

The nitrogen gas GN introduced into the condensing channel 35 condenses by performing heat exchange with the liquefied oxygen LO in the upflow heat transfer area 27 of the adjacent oxygen chamber 22 and condensing with the descending gradient of the condensing channel 35. exit
38 toward the condensate outlet port 38,
And is discharged from the condensate outlet header 42 as liquefied oxygen LN. This liquefied nitrogen LN is used as a reflux liquid for the upper tower 6 and the lower tower 13 or is collected as a product as in the conventional case. In addition, the non-condensed gas GX in the nitrogen gas GN is a purge nozzle 40a provided at the upper part of the gas inlet header 40.
Derived from.

In this way, the nitrogen gas GN is introduced from the gas inlets 37 at both end portions of the nitrogen chamber 31 into the condensing passages 35 having a downward slope, and is led out from the condensate outlet port 38 in the central portion, whereby the nitrogen chamber
31 Since the nitrogen gas GN amount introduced into each condensing channel 35 in the vertical direction and the liquefied nitrogen LN amount condensed in the channel 35 can be made substantially the same, the film heat transfer coefficient can be made substantially the same in the vertical direction. it can.

Therefore, the liquefied oxygen LO under the upflow heat transfer area 26 of the oxygen chamber 22
Since sufficient heat exchange can be performed with both, heat transfer performance by condensation evaporation can be maximized. Particularly in a large tall condensing evaporator, the length of the condensing channel 35 can be significantly shortened, so that a liquid film of liquefied nitrogen LN formed near the condensate outlet 38 of each condensing channel 35. Can be made thinner, and the decrease in heat transfer performance can be minimized.

Furthermore, since the cross-sectional area of the condensing channel 35 increases and the opening areas of the gas inlet 37 and the condensate outlet 38 can also be increased, the amount of condensation per condensing channel cross-sectional area and the flow resistance decrease, and The exchange efficiency can be further improved. Further, since the eaves-shaped liquid draining portion 39 is provided in a part of the condensate outlet 38 in the vertical direction, the condensed liquefied nitrogen LN can be smoothly led out. The liquid draining section 39 does not have the condensate outlet 38 of the condensing flow path 35 in a stepwise shape, and when it is provided in a straight line in the vertical direction, by providing an eaves-shaped liquid draining plate in a suitable place, the same. The liquid draining effect of can be obtained.

In this way, by arranging the downflow heat transfer area 26 in the center of the oxygen chamber 22, and by arranging the condensate descending path 36 in the center of the nitrogen chamber 31 in correspondence with this, the condensation flow path of the nitrogen chamber 31 is arranged. Although the length 35 can be shortened significantly, it is also possible to dispose the downflow heat transfer region 26 on one side of the oxygen chamber 22 and correspondingly make one side of the nitrogen chamber 31 the condensate flow path 36.

The operation control of the condenser / evaporator 20 is performed in the same manner as in the past by adjusting the derivation amount of the liquefied oxygen LO and adjusting the heat load by providing a liquid level gauge L and the like. The liquid level height of the liquefied nitrogen LN in the nitrogen chamber 31 is adjusted by adjusting the amount of liquefied nitrogen LN discharged from the outlet header 42, and the contact area between the heat transfer body 34 and the nitrogen gas GN in the nitrogen chamber 31 is adjusted. By increasing or decreasing, the heating capacity of the liquefied oxygen LO in the oxygen chamber 22 adjacent to the nitrogen chamber 31 can be changed. As a result, the amount of condensed liquefied oxygen LO and the amount of condensed nitrogen gas GN can be adjusted and controlled, and a wide range of control corresponding to the operating state of the air liquefaction separation device becomes possible.

The condenser evaporator 20 of the present embodiment is arranged in the space 21 where the pressure is released in the cold box by the opening 21a of the side wall, and the space 21 is filled with a heat insulating material or the like. May be.

FIG. 3 shows a temperature distribution diagram in the condensation evaporator, and illustrates the operation of the condensation evaporator of the present invention.

First, FIG. 3 (a) shows the temperature distribution in the conventional condensing evaporator shown in FIG. 9 and FIG. The temperature distribution at the time of introducing and liquefying liquefied oxygen LO of saturation temperature Ts and nitrogen gas of saturation temperature Tc is shown. The liquefied oxygen LO circulates around the outer periphery of the condensation evaporator 1 and is introduced into the oxygen chamber 2 through the inlet 4 at the lower end, but during this time, since there is no heat exchange, the liquefied oxygen temperature Tsb is It is almost equal to the saturation temperature Ts in the vicinity. However, the liquefied oxygen LO in the oxygen chamber 2 has a saturation temperature increased by the pressure increase due to the liquid depth of the liquefied oxygen itself, and has a saturation temperature Td shown by a chain line in the figure. Therefore,
The liquefied oxygen LO flowing into the lower part of the oxygen chamber 2 is in a supercooled state of the temperature Tsb with respect to the saturation temperature Td. Therefore, the liquefied oxygen LO is heated by convective heat transfer while rising in the oxygen chamber 2, and reaches the saturation temperature Td at point A. In order for the fluid to boil, a certain degree of superheat is required for its saturation temperature, so the liquefied oxygen LO is further heated to reach the boiling start temperature Tsp at point B, which has a sufficient degree of superheat for boiling nucleation. .
Liquefied oxygen LO above this point B is oxygen gas from the heat transfer surface.
The bubbles of GO are generated by boiling and become a gas-liquid mixed flow, which rises while showing the saturation temperature Td at that height (liquid depth),
It flows out from the outlet 5 in the upper part of the oxygen chamber 2. Thus, heating unit Z ₁ from below into the oxygen chamber 2, superheating zone Z _2, 3 of the boiling portion Z ₃
It is divided into two heat transfer areas. The portion of the liquefied oxygen LO that is not involved in the evaporation, that is, the sum of the heating section Z ₁ and the superheating section Z ₂ represents the single relative flow heat transfer area of the liquefied oxygen LO. On the other hand, it reached 20 to 40%, which was a cause of greatly reducing the heat transfer performance of the entire condensation evaporator. In addition, the heating of the liquefied oxygen LO before the start of boiling was inefficient because it was performed by convective heat transfer, which has a low heat transfer performance, and deteriorated the efficiency of the entire condensation evaporator.

FIG. 3B shows the temperature distribution in the condenser-evaporator of the present invention, which shows the downward flow heat transfer region from the liquid medium reservoir 24 to the oxygen chamber 22.
Since the liquefied oxygen LO flowing down the 26 is heated by the nitrogen gas in the adjacent nitrogen chamber, the temperature Tsb of the liquefied oxygen when flowing into the upflow heat transfer region 27 from the communication passage 28 at the lower end of the oxygen chamber 22.
Rises to near the saturation temperature Td due to the liquid depth. Therefore,
The liquefied oxygen LO reaches the saturation temperature Td at the point A immediately after flowing into the upflow heat transfer region 27, reaches the boiling start temperature Tsp at the point B slightly increased from the point A, and starts boiling evaporation. After that,
Similar to the above, it rises at the saturation temperature Td at that height.

In this way, the liquefied oxygen LO is heated in the downflow heat transfer area 26,
By setting the saturation temperature Td at the position where it flows into the upflow heat transfer area 27 or near the boiling start temperature Tsp, the length of the heating part Z _{1 and} further the superheat part Z _{2 in} the upflow heat transfer area 27 is significantly reduced. can do. Further, as described above, since the heat transfer efficiency in the lower part of the nitrogen chamber is improved, it is possible to raise the liquefied oxygen LO to the boiling start temperature Tsp in a short time, which also enables the heating section Z ₁ and the superheating section Z _{2 to be} heated. Can be shortened.

As a result, substantially the entire height of the condenser-evaporator 20 can be used as the boiling portion Z ₃ , so that the heat transfer efficiency can be improved, and the downflow heat transfer area 26 that is a single liquid phase and the gas-liquid mixed phase can be used. The liquid head difference with the upward flow heat transfer region 27, which is a flow, becomes large, and the circulation amount of the liquefied oxygen LO can be increased.
Therefore, it is possible to prevent the formation of a dry region where acetylene may be concentrated in the boiling section Z ₃ . Further, by arranging the downflow heat transfer area 26 of the oxygen chamber 22 and the condensate flow-down passage 36 of the nitrogen chamber 31 adjacent to each other, which has relatively low heat transfer performance because the condensate collects and flows down, Liquefied oxygen LO is heated in the flow heat transfer area 26 to a temperature above the boiling start temperature Tsp,
O can be prevented from evaporating and obstructing the circulation.

Next, FIGS. 4 and 5 show a second embodiment of the condensing evaporator of the present invention. FIG. 4 shows an oxygen chamber part and FIG. 5 shows a nitrogen chamber part. The oxygen chamber, the nitrogen chamber, and the like have the same configurations as those in the first embodiment, and therefore, the same reference numerals are given and detailed description thereof is omitted.

The condensing evaporator 50 is arranged in a nitrogen gas atmosphere in the upper part of the lower tower 13, the oxygen chamber 22 part is completely sealed, and the nitrogen chamber 31 part is opened to the nitrogen gas atmosphere. Further, below the condensing evaporator 50, its upper opening edge 51a is formed.
Condensate reservoir formed up to the appropriate position of the condenser evaporator 50
51 is provided.

The upper portion of the oxygen chamber 22 is provided with a liquid medium reservoir 24 which is provided above and spaced apart.
And an oxygen header 52 and a connecting pipe 53. The oxygen header 52 and the connecting pipe 53 are formed in a double structure, and the inner side serves as the lower part 54 of the liquefied oxygen LO and the outer side serves as the rising part 55 of the gas-liquid mixed flow of oxygen gas GO and liquefied oxygen LO. There is. Therefore, the liquefied oxygen LO is transferred from the liquid medium reservoir 24 to the connecting pipe 53.
And is introduced into the downflow heat transfer area 26 by flowing down the lower stream 54 of the oxygen header 52, and through the communication passages 28, 28, the upflow heat transfer area 27,
It flows into 27, a part of it evaporates to become a gas-liquid mixed flow, and rises and circulates in the liquid medium reservoir 24 via the oxygen header 52 and the rising portion 55 of the connecting pipe 53.

Similarly, one of the nitrogen chambers 31 is open to the nitrogen gas atmosphere in the lower tower 13 except that the upper end is closed by the side bar 33. Therefore, the nitrogen gas GN can freely flow into and out of the nitrogen chamber 31, and a part of the nitrogen gas GN can condense in the condensation flow paths 35 and 3.
Condensed at 5 to become liquefied nitrogen LN, which flows down the downward gradient of the condensation flow path 35 and gathers in the condensed liquid flow-down path 36, and flows down from the lower end of the nitrogen chamber 31 to the condensed liquid reservoir 51 below. Since the nitrogen chamber 31 is opened to the nitrogen gas atmosphere in the upper part of the lower tower 13, the non-condensed gas GX is not concentrated in the nitrogen chamber 31 and the condensing capacity is not lowered.

Further, the operation control of the condensing evaporator 50, in addition to the conventional control means, controls the amount of liquefied nitrogen LN discharged from the condensate reservoir 51 to immerse the lower part of the condensing evaporator 50 in the liquefied nitrogen LN. It can also be performed by adjusting the amount and increasing or decreasing the contact area between the heat transfer body 34 in the nitrogen chamber 31 and the nitrogen gas GN as in the first embodiment.

6 to 8 show a third embodiment of the condenser-evaporator of the present invention.

Condensation evaporator 60 of the present embodiment, a part of a large number of oxygen chambers, the liquid medium heating greenhouses 61, 61 to be the downflow heat transfer region, the other oxygen chamber liquid medium evaporation to be the upflow heat transfer region It is a room 62, 62. The liquid medium heating greenhouse 61 and the liquid medium evaporation chamber 62 are communicated with each other by communication pipes 63, 63 provided at the lower portions on both sides of the condensation evaporator 60, and the liquefied oxygen LO flowing down the liquid medium heating chamber 61 is
It flows into the liquid medium evaporation chamber 62 via this communication pipe 63. Both rooms
Inside the 61, 62, there is a heat transfer body 64 such as a corrugation fin.
Are appropriately arranged. However, inside the liquid medium evaporation chamber 62, it is possible to reduce the flow resistance by forming the boiling promoting nucleus heat transfer surface as described above without disposing the heat transfer body 64.

Further, in the liquid medium reservoir 65, an introduction liquid reservoir 66 and an introduction channel 67 for introducing the liquefied oxygen LO into the liquid medium heating greenhouse 61 are formed, and introduced into the liquid medium reservoir 65 by the liquefied oxygen introduction pipe 30. The liquefied oxygen LO thus obtained is introduced into the liquid medium-added greenhouse 61 through the introduction liquid reservoir 66 and the introduction flow path 67, flows down, passes through the conduit tube 63, and flows into the lower portion of the liquid medium evaporation chamber 62. And, like the above-mentioned embodiments,
Liquid-medium reservoir becomes a gas-liquid mixed flow of liquefied oxygen LO and oxygen gas GO
It rises to 65 and circulates. This liquid medium heating chamber 61 and liquid medium evaporation chamber
The temperature and flow rate of the 62 can be balanced by changing its thickness.

One of the nitrogen chambers 68, 68 can be formed with the same structure as the nitrogen chamber shown in each of the above-mentioned embodiments, and thus detailed description thereof will be omitted.

In the above description, the description is based on the evaporation and condensation by the heat exchange between liquefied oxygen and nitrogen gas in the air liquefaction separation, but the same effect is obtained when other liquid mediums and gas fluids are used. The effect can be obtained. Also, the relationship between the area of the liquid medium introduction portion and the liquid medium evaporation portion of the oxygen chamber, the angle of the gradient of the condensation flow path of the nitrogen chamber, the shape of each other part, etc., depend on the type and flow rate of the liquid medium and gas fluid. It can be appropriately selected.

〔The invention's effect〕

As described above, the condensing evaporator of the present invention is provided with a liquid medium reservoir in the upper part of the condensing evaporator, and in the first fluid chamber, a downward flow heat transfer region for heating the liquid medium to near the boiling start point, and a liquid Since the upflow heat transfer area for heating the medium above the boiling start point is provided, and the liquid medium is configured to evaporate while circulating in the liquid medium reservoir and the first fluid chamber, the condenser evaporator with a small amount of the liquid medium. Can be operated, shortening the start-up time, reducing refrigerant loss at the time of stop, solving safety problems, etc., especially by raising the liquid medium to the boiling start temperature in the downward flow heat transfer area Since it can be boiled and evaporated immediately in the flow heat transfer area, the effect of the liquid depth is reduced, the effective activity in the height direction of the condensation evaporator and the improvement of the heat transfer efficiency on the boiling side, and the head difference required for the circulation of liquefied oxygen. Can be increased.

By disposing the corrugation fins in the upflow heat transfer area of the first fluid chamber, the heat transfer coefficient can be improved to achieve efficient boiling evaporation, and the surface of the upflow heat transfer area can be provided with a boiling promoting nucleus. By forming the heat transfer surface, it is possible to promote boiling evaporation and reduce flow resistance.

Further, the both flow paths are formed by partitioning rods in the first fluid chamber.
It can be easily formed by partitioning into one flow path, or a part of the plurality of first fluid chambers is used as a liquid medium heating greenhouse and the other is used as a condensation evaporation chamber so that the lower ends of both chambers communicate with each other. Can also be easily formed.

Further, by disposing the downflow heat transfer area of the first fluid chamber in the vicinity of the condensate outlet of the second fluid chamber, the liquid medium evaporates in the downflow heat transfer area and hinders circulation. Can be prevented.

On the other hand, in the second fluid chamber, a condensing channel having a downward gradient with respect to the horizontal direction from the gas inlet to the condensate outlet is formed, and the gas fluid is introduced from one end to flow down to the other side. Therefore, the gas fluid can be introduced substantially evenly in the vertical direction of the second fluid chamber, and the liquid medium in the lower portion of the first fluid chamber can be efficiently heated. Also, since the condensing channel can be formed short, the liquid film of the condensate can be thinned,
The film heat transfer coefficient on the condensation side can be improved.

In addition, the condensing flow path of the second fluid chamber can be easily formed by corrugation fins, and the condensate drain port is provided at a part of the condensate drain port so that the lower condensate outlet port flows down. Can be prevented from being blocked by the condensate. This second fluid chamber is easily closed by closing the upper end and opening both side ends and the lower end, and using the opening at one side end as the gas inlet and the other opening as the condensate outlet. Can be formed.

In particular, the first fluid chamber is divided by two partition rods so that the central portion serves as the downward flow heat transfer area and both side portions serve as the upward flow heat transfer area. By providing a downflow path and opening the condensate outlet of the condensate flow path in the condensate downflow path, the condensate flow path can be formed shorter and the influence of the liquid film of the condensate can be significantly reduced. You can

Further, the operation method of the condensation evaporator of the present invention, the liquid medium flowing down the downflow heat transfer region of the first fluid chamber, the temperature below the boiling start point of the liquid medium by adjusting the flow rate and the like. Since it is introduced into the upflow heat transfer area after it has been heated up, it is possible to immediately evaporate it in the upflow heat transfer area, improving the heat transfer efficiency on the boiling side and increasing the head difference required for the circulation of liquefied oxygen. Therefore, since the circulation amount of liquefied oxygen increases, it is possible to prevent the formation of a dry region in the evaporation portion and to take effective security measures.

Further, the control of the operation capacity is performed by adjusting the amount of the condensed liquid discharged from the condensed liquid reservoir provided below the condensing evaporator or the header connected to the lower part of the condensing evaporator to change the amount of the condensed liquid in the second fluid chamber. By doing so, the heat transfer area can be controlled to adjust the evaporative condensation capacity, and a wide range of control can be performed by adding this method to the conventional control means.

Therefore, it is particularly suitable for a condenser / evaporator of a large-scale air liquefaction / separation device having a large amount of treatment, and it is possible to reduce the size of the entire device, reduce the operating power cost, and reduce the power consumption of the product.

[Brief description of drawings]

1 and 2 show a first embodiment of a condensation evaporator according to the present invention. FIG. 1 is a sectional view showing an oxygen chamber portion of the condensation evaporator incorporated in a double rectification column, and FIG. The figure is also a sectional view showing the nitrogen chamber portion, FIG. 3 is an explanatory view of the temperature distribution in the condensing evaporator, and FIGS. 4 and 5 show the second embodiment of the condensing evaporator of the present invention. 4 is a sectional view showing the oxygen chamber portion,
FIG. 5 is a sectional view showing a nitrogen chamber portion, FIGS. 6 to 8 show a third embodiment of the condensing evaporator of the present invention, and FIG. 6 is a sectional side view of the condensing evaporator, and FIG. Fig. 8 is a sectional front view showing a liquid medium heating greenhouse, Fig. 8 is a sectional front view showing a liquid medium evaporation chamber, Figs. 9 and 10 show conventional examples, and Fig. 9 shows a double rectification column. Sectional view showing the oxygen chamber part of the built-in condensing evaporator,
FIG. 10 is a sectional view showing the nitrogen chamber portion. 6 …… Upper tower, 13 …… Lower tower, 20,50,60 …… Condensation evaporator, 22 …… Oxygen chamber, 24,65 …… Liquid medium reservoir, 25 …… Partition rod, 2
6 …… Downflow heat transfer area, 27 …… Upflow heat transfer area, 28 ……
Communication passage, 29,34,64 ... Heat transfer body, 31,68 ... Nitrogen chamber, 35 ...
… Condensation channel, 36 …… Condensate flow path, 37 …… Gas inlet,
38 ... Condensate outlet, 39 ... Drainage part, 42 ... Condensate outlet header, 51 ... Condensate reservoir, 61 ... Liquid medium heating greenhouse, 62 ...
… Liquid medium evaporation chamber, 63 …… Communication pipe, GN …… Nitrogen gas, GO ……
Oxygen gas, LN ... Liquefied nitrogen, LO ... Liquefied oxygen

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-56-56592 (JP, A) JP-A-56-130201 (JP, A) JP-A-63-187085 (JP, A) JP-B-40- 18206 (JP, B1) JP-B 49-37627 (JP, B1) JP-B 4-14269 (JP, B2) JP-B 6-68434 (JP, B2) Actual JP-61-42072 (JP, Y2) Actual public Sho 63-47831 (JP, Y2) Actual public Sho 63-49676 (JP, Y2)

Claims (10)

[Claims] 1. A plurality of vertical partition plates alternately form a plurality of first fluid chambers and second fluid chambers, and a liquid medium in the first fluid chambers and a gas fluid in the second fluid chambers are formed. In a condensing evaporator performing heat exchange, a liquid medium reservoir is provided above the condensing evaporator, and in the first fluid chamber, a downward flow heat transfer region for heating the liquid medium to near the boiling start point, and the liquid medium. Is provided with an ascending flow heat transfer region for heating above the boiling start point, the descending flow heat transfer region and the ascending flow heat transfer region are communicated with each other in the lower part of the first fluid chamber, and the upper part of both regions is provided with the liquid medium reservoir. And the heat transfer area of the downward flow heat transfer area of the first fluid chamber is such that the liquid medium heated while flowing down the area is at the lower end of the area and has a saturation temperature corresponding to the lower end pressure. A condenser-evaporator characterized by being set as follows. 2. A part of the plurality of first fluid chambers is a liquid medium heating greenhouse which is a downflow heat transfer region, and the remaining chambers are liquid medium evaporation chambers which are upflow heat transfer regions. The condensing evaporator according to claim 1, wherein the lower end portions of both chambers are made to communicate with each other by a communication passage. 3. The first fluid chamber is divided into at least three flow passages in the width direction by at least two partition rods arranged from the upper end to the vicinity of the lower end of the chamber, and the flow in the central portion is formed. The passage is used as a downward flow heat transfer area, the flow passages on both sides are used as an upward flow heat transfer area, and the second fluid chamber is opened at both widthwise end portions to serve as gas inlets, and the width of the second fluid chamber is set. A condensate flow-down passage having a lower end opening corresponding to the downward flow heat transfer region of the first fluid chamber is provided at a central portion in the direction, and a condensate discharge port of the condensation flow passage is opened in the condensate flow-down passage. The condensing evaporator according to claim 1, characterized in that. 4. The second fluid chamber has at least one end opened to form a gas introduction port for introducing a gas fluid, and with respect to a horizontal direction from the gas introduction port to the condensate discharge port. The condensing evaporator according to claim 1, wherein a condensing channel having a downward slope is formed. 5. The second fluid chamber has an upper end portion closed and both side end portions or both side end portions and a lower end portion opened.
The condensate evaporator according to claim 4, wherein the opening at one side end is a gas inlet, and the opening at the other side end or the other side end and a lower end is a condensate outlet. 6. A liquid draining portion is provided so as to protrude from a part of a condensate outlet of a condensing passage of the second fluid chamber.
Alternatively, the condensing evaporator according to claim 4 or claim 5. 7. When operating the condensing evaporator according to claim 1, the liquid medium introduced from the liquid medium reservoir and flowing down in the downward flow heat transfer region of the first fluid chamber is transferred to the adjacent second fluid chamber. The gas fluid is heated to a temperature near the boiling start point of the liquid medium, and then introduced into an upward flow heat transfer region to heat the liquid medium to a temperature above the boiling start point of the liquid medium to evaporate the liquid medium, A method for operating a condensation evaporator, wherein an unevaporated liquid medium is circulated from the liquid medium reservoir into the downflow heat transfer region. 8. The liquid medium supply amount is adjusted so that the liquid medium flowing in the downward flow heat transfer region of the first fluid chamber has a saturation temperature corresponding to the pressure at the lower end at the lower end of the region. The method of operating the condensation evaporator according to claim 7. 9. A condensate that condenses in the second fluid chamber and flows down below the condensing evaporator when controlling the condensing and evaporating capacity of the condensing evaporator during the operation of the condensing evaporator according to claim 1. A condensate reservoir for accumulating the condensate, and adjusting the amount of the condensate discharged from the condensate reservoir to change the amount of the lower part of the second fluid chamber immersed in the condensate. Method. 10. Instead of the condensate reservoir according to claim 9, a header for condensing the condensate condensed in the second fluid chamber and flowing down is continuously provided under the condensing evaporator, and is led out from the header. A method for operating a condensing evaporator, wherein the amount of condensate is adjusted to change the amount of condensate in the second fluid chamber.