JPH0730996B2 - Condensing evaporator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention heat-exchanges a liquid medium in a first fluid chamber and a gas fluid in a second fluid chamber to evaporate and vaporize the liquid medium and condense the gas fluid. The present invention relates to a condensing evaporator for liquefying, particularly a condensing evaporator used in an air liquefying / separating device, in which the liquid medium introduced into the first fluid chamber, that is, liquefied oxygen introduced into the oxygen chamber is efficiently boiled and evaporated. The gas fluid introduced into the fluid chamber relates to a condenser / evaporator suitable for efficiently condensing and liquefying the nitrogen gas introduced into the nitrogen chamber.

[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.

FIG. 5 shows an oxygen chamber of a conventional plate fin type condensing evaporator, and FIG. 6 also shows a nitrogen chamber. In each of the following drawings, a solid arrow indicates a flow direction, and a chain arrow indicates a gas flow direction.

The oxygen chamber 2 of the condensing evaporator 1 has a heat transfer plate disposed therein to form a large number of vertical evaporation passages 3, and the upper and lower end portions of the evaporation passage 3 are opened to open the lower end portion. Liquefied oxygen LO
Of the mixed gas of oxygen gas GO and liquefied oxygen LO. The oxygen chamber 2 is filled with liquefied oxygen LO by immersing the condensation evaporation chamber 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. Heat exchange is performed with the nitrogen gas GN in the nitrogen chamber 7, a part of which 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 condensation evaporator 1 due to the density difference between the gas-liquid mixed phase of the liquefied oxygen LO in the oxygen chamber 2 and the vaporized oxygen gas GO and the liquefied oxygen LO outside the oxygen chamber. ing. 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 flow paths 8 are formed in a chamber where each end of the four circumferences is sealed, and both upper and lower ends of the condensing flow path 8 are located above and below one side end of the nitrogen chamber 7. It is connected to the lower tower 13 via the provided headers 9 and 10 and pipes 11 and 12. In this nitrogen chamber 7, the nitrogen gas GN in the upper part of the upper tower 13 is introduced as a descending flow into the condensing passage 8 via the pipe 11 and the upper header 9, and the liquefied nitrogen LN condensed in the condensing passage 8 is supplied to the lower header. It is derived from 10 and piping 12. Further, the non-condensed gas GX contained 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, in the nitrogen chamber 7 of the conventional condensing evaporator 1, the condensing channel 8 is formed in the vertical direction, and the nitrogen gas GN flows down while condensing. Therefore, the amount of liquefied nitrogen in the lower part of the condensing channel 8 is reduced. Increases, and a thick liquid film covers the surface of the heat transfer surface, which becomes a heat resistance layer and deteriorates the heat transfer performance. Therefore, the liquefied oxygen LO rising in the lower portion of the evaporation channel 3 of the oxygen chamber 2 cannot be sufficiently heated, and the heat transfer efficiency of the condenser evaporator 1 is reduced.

Therefore, the present invention reduces the decrease in heat transfer performance due to the condensed liquid of the nitrogen gas (gas fluid) in the nitrogen chamber (second fluid chamber), and reduces the liquefied oxygen (liquid medium) on the oxygen chamber (first fluid chamber) side. It is an object of the present invention to provide a condensing evaporator capable of efficiently heating).

[Means for solving problems]

In order to achieve the above-mentioned object, the present invention forms a plurality of first fluid chambers and second fluid chambers alternately by a large number of vertical partition plates, and a liquid medium of the first fluid chamber and the second fluid chamber. In a condenser-evaporator that exchanges heat with a gas fluid in a fluid chamber, substantially the entire side surfaces of the second fluid chamber are opened so that one opening serves as a gas inlet for introducing the gas fluid and the other opening. Is a condensate outlet for condensing liquid, and a condensing evaporator characterized in that a condensing passage having a downward gradient from the gas inlet to the condensate outlet is formed in the horizontal direction. Further, the second fluid chamber further comprises a gas inlet and a condensate outlet at both ends covered with an inlet and an outlet header, respectively, to hermetically seal both headers to the gas fluid and condensate sides. Connect to each other and above and below the first fluid chamber The end portion is opened, the condenser evaporator itself is immersed in the liquid medium on the evaporation side, and the first fluid chamber is covered with outlet and inlet headers at the upper and lower ends, respectively, and pressure-tightly sealed. Both headers are respectively connected to the evaporative gas and the liquid medium side, both side ends of the second fluid chamber are opened, and the condenser evaporator itself is arranged in the gas fluid atmosphere on the condensing side. In addition, it also includes the provision of a liquid draining part at a part of the condensate outlet of the second fluid chamber configured as described above.

[Work]

As described above, by forming the condensing flow path of the second fluid chamber in a downward gradient from the gas introduction port at the one end to the condensate outlet at the other end, gas is also generated in the lower part of the second fluid chamber. Since the fluid can be introduced substantially uniformly, the liquid medium in the lower part of the first fluid chamber can be efficiently heated. Particularly in a tall condensing evaporator used in a large-sized air liquefaction separator, the condensing channel can be shortened, so that the amount of condensate in each condensing channel can be reduced and the liquid film generated can be thinned. The heat transfer efficiency can be improved. Further, by providing headers at both side openings of the second fluid chamber and connecting them to the gas fluid side, they can be arranged by being immersed in a liquid medium as in the case of the conventional condenser evaporator. On the other hand, connect the first fluid chamber to the liquid medium side with a header,
By arranging the condensation evaporator itself in the gas fluid atmosphere, it is possible to operate with a smaller amount of liquid medium as compared with the case where the condensation evaporator is immersed in the liquid medium and arranged. Also, by providing a drainage part at the condensate outlet of the second fluid chamber, it is possible to prevent the condensate flowing down from the condensate passage of the upper part of the second fluid chamber from blocking the condensate outlet of the condensate passage of the lower part. can do.

〔Example〕

Hereinafter, using the condensation evaporator of the present invention in a double rectification column, the first fluid chamber is an oxygen chamber, the second fluid chamber is a nitrogen chamber, the liquid medium to be evaporated is oxygen, the gas fluid to be condensed is an example of nitrogen Will be described in more detail with reference to the drawings. 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 an embodiment in which a condenser evaporator is arranged in the upper bottom space of a double rectification column. FIG. 1 shows a nitrogen chamber and FIG. 2 shows an oxygen chamber. Shows.

The nitrogen chamber 21 of the condenser evaporator 20 has side bars at the upper end and the lower end of each chamber partitioned by a vertical partition plate.
It is closed by 22,22, and substantially the entire surfaces of both ends are opened, one opening is used as a gas inlet 23 for nitrogen gas GN (gas fluid), and the other opening is used for condensation of liquefied nitrogen LN (condensate). The liquid outlet 24 is provided. Inside the nitrogen chamber 21, a large number of condensing passages 25, both ends of which communicate with the gas inlet 23 and the condensate outlet 24, are formed by heat transfer plates such as corrugation fins.

This condensation channel 25 is a liquefied nitrogen LN condensed in the condensation channel 25.
In order to allow the gas to flow out through the condensate outlet 24, an appropriate downward gradient is provided from the gas inlet 23 toward the condensate outlet 24 in the horizontal direction. Further, the condensate outlet 24 of the condensing channel 25 has a liquid draining portion 26 formed in a part in the vertical direction. The liquid draining section 26 guides the liquefied nitrogen LN flowing down from the condensate outlet 24 of the upper condensing channel 25, and the liquefied nitrogen LN flowing down from above flows down along the condensate outlet 24. The condensate outlet 24 of the lower condensing channel 25 is prevented from being blocked with a liquid film.

An inlet header 27 and an outlet header 28 are connected to both ends of the nitrogen chamber 21 in a continuous manner to be pressure-sealed from the outside. The inlet header 27 is connected to the lower tower 13, and the nitrogen gas GN rectified and separated in the upper portion of the lower tower 13 is introduced into the nitrogen chamber.
Introduce to 21. One outlet header 28 is connected to an appropriate pipe 29 for discharging the condensed liquefied nitrogen LN as a reflux liquid of the upper tower 6 and the lower tower 13 or as a product.

The oxygen chamber 2 adjacent to the nitrogen chamber 21 via the partition plate is formed in the same manner as in the conventional example shown in FIG. 5, and the upper and lower ends are opened so that the inlet 4 and the outlet 5 are formed. A heat transfer plate is arranged in the formed chamber to form a large number of vertical evaporation channels 3.

The nitrogen gas GN introduced into this condenser evaporator 20 is the lower tower 13
It is introduced from the upper part through the inlet header 27 into each condensing channel 25 substantially uniformly. The nitrogen gas GN in each condensing channel 25 heat-exchanges with the liquefied oxygen LO in the adjacent oxygen chamber 2 to condense,
It flows toward the condensate outlet 24 due to the descending gradient of the condensing channel 25, flows down from the condensate outlet 24, and is led out from the outlet header 28. At this time, non-condensed gas contained in nitrogen gas GN
GX is a purge nozzle provided above the inlet header 27.
Derived from 27a.

On the other hand, the liquefied oxygen LO flowing down from the upper tower 6 circulates inside and outside the condensation evaporator 20 as in the conventional case, and a part thereof is evaporated to become oxygen gas GO. A part of this oxygen gas GO is discharged as a product, and the rest is the rising gas of the upper tower 6. Further, a part of the liquefied oxygen LO is derived as a product or a safeguard liquid acid.

As described above, the condensing evaporator 20 introduces the nitrogen gas GN from the gas introducing port 23 at one end of the nitrogen chamber 21 into each condensing passage 25 and the condensate outlet 24 at the other end. Therefore, the film heat transfer coefficient in the vertical direction of the nitrogen chamber 21 can be made substantially the same. Therefore, since sufficient heat exchange can be performed with the liquefied oxygen LO in the lower part of the oxygen chamber 2, the heat transfer performance by condensation evaporation can be maximized. In particular, in a large tall condenser evaporator, the length of the condensing channel 25 can be shortened compared to the conventional one, so that the liquid film formed in the vicinity of the condensate outlet 24 of each condensing channel 25 is thin. It is possible to minimize the decrease in heat transfer performance. Further, the cross-sectional area of the condensing channel 25 increases, and the gas inlet 23 and the condensate outlet
Since the opening area of 24 also increases, the amount of condensation per cross-sectional area of the condensation channel 25 and the flow resistance decrease, and the heat exchange efficiency can be further improved. Further, by providing the eaves-shaped liquid draining portion 26 in a part of the condensate outlet 24 in the vertical direction, the condensed liquefied nitrogen LN can be smoothly led out.

Next, FIG. 3 and FIG. 4 show an embodiment in which the condenser-evaporator of the present invention is arranged in the lower column upper space of the double rectification column. FIG. The figure shows the oxygen chamber.

First, the nitrogen chamber 21 formed in the same manner as in the above embodiment is
13 Nitrogen gas GN in the upper space freely flows into the nitrogen chamber 21,
Gas inlets 23 at both ends to allow outflow
The condensate outlet 24 is opened almost completely in the upper space of the lower tower 13. A part of the nitrogen gas GN that has flowed into the nitrogen chamber 21 is condensed in the condensing channel 25 to become liquefied nitrogen LN, as in the above embodiment, and flows down the downward gradient of the condensing channel 25 to reach the condensate outlet. Run down from 24. Below the condensing evaporator 20, a liquefied nitrogen reservoir 30 whose upper opening edge 30a reaches an appropriate position of the condensing evaporator 20 is provided, and the liquefied nitrogen LN flows down into the liquefied nitrogen reservoir 30. Then, it is led out from the pipe 29 similar to the above-mentioned embodiment.

On the other hand, in the outlet 5 and the inlet 4 at the upper and lower ends of the oxygen chamber 2,
Oxygen headers 31 and 32 are provided respectively, and connecting pipe 3
It is connected to the liquefied oxygen reservoir 6a at the bottom of the upper tower 6 through 3,34. Liquefied oxygen LO flowing down from the upper tower 6 to the liquefied oxygen reservoir 6a
Flows down from the liquefied oxygen reservoir 6a through the connection pipe 34 on the downflow side and flows into the channel 3 through the oxygen header 32 in the lower part of the oxygen chamber 2.
Similar to the above embodiment, a part of this liquefied oxygen LO is evaporated into a gas-liquid mixed flow in the evaporation channel 3, and rises to the liquefied oxygen reservoir 6a via the upper oxygen header 31 and the connecting pipe 33. Then, the oxygen gas GO separates from the liquefied oxygen LO and rises, and the liquefied oxygen LO circulates again from the connection pipe 34 on the downflow side to the oxygen chamber 2.

Also in this embodiment, as in the above embodiment, since the boundary film heat transfer coefficient in the vertical direction of the nitrogen chamber 21 can be made substantially the same, sufficient heat exchange with the liquefied oxygen LO under the oxygen chamber 2 is also required. It is possible to maximize the heat transfer performance by condensation and evaporation. Further, the operation control of the condensation evaporator 20 in the present embodiment, in addition to the conventional control method, by controlling the amount of liquefied nitrogen LN derived from the liquefied nitrogen reservoir 30, namely, the liquefied nitrogen LN in the liquefied nitrogen reservoir 30. It can also be performed by controlling the liquid level height to control the amount of the lower part of the condenser evaporator 20 immersed in the liquefied nitrogen LN, and increasing or decreasing the substantial amount of nitrogen gas GN in the nitrogen chamber 21. This allows
A wide range of control is possible according to the operating state of the air liquefaction separation device.

Further, as in this embodiment, the condenser evaporator 20 is arranged in the upper space of the lower tower 13, that is, in the nitrogen gas GN atmosphere, and the oxygen chamber 2 and the liquefied oxygen reservoir 6a at the bottom of the upper tower 6 are connected to the oxygen header 31, Connect the condenser evaporator 20 to the liquefied oxygen LO
The condensation evaporator 20 can be operated with a smaller amount of liquefied oxygen as compared with the case where the condenser evaporator 20 is immersed therein. Therefore, since it is not necessary to store a large amount of liquefied oxygen LO at the bottom of the upper tower 6, the device start-up time can be shortened, and the amount of liquefied oxygen released when the device is stopped is reduced. Losses can be reduced and operating costs can be reduced. Further, since the amount of liquefied oxygen is small, it is possible to easily deal with a security problem in case of emergency.

The condensing evaporator of the present invention has the same function in the case of heat exchange between other liquid medium and gas fluid other than evaporation and condensation by heat exchange between liquefied oxygen and nitrogen gas in air liquefaction separation. The effect can be obtained.

〔The invention's effect〕

As described above, according to the present invention, since the condensing flow path for condensing the gas fluid is formed in a downward gradient with respect to the horizontal, the gas fluid can be evenly introduced into the lower part of the second fluid chamber. The lower liquid medium can be efficiently heated. Particularly in a large-sized condensing evaporator, the condensing flow path can be significantly shortened, so that the liquid film of the condensate in each condensing flow path can be thinned, and the heat transfer efficiency can be improved. In addition, the cross-sectional area of the condensing channel increases compared to the conventional one, and the opening areas of the gas inlet and the condensate outlet also increase, so the amount of condensation per evaporative channel cross-sectional area and the flow resistance decrease, and heat exchange The efficiency can be improved.

Further, by providing headers at both side openings of the second fluid chamber and connecting them to the gas fluid side, they can be arranged by being immersed in a liquid medium as in the case of the conventional condenser evaporator.

On the other hand, by connecting the first fluid chamber to the liquid medium side by a header and arranging the condensation evaporator itself in the gas fluid atmosphere,
It is possible to operate with a small amount of liquid medium, shorten the startup time of the device, reduce power cost, and obtain other effects.

Also, by providing a drainage part at the condensate outlet of the second fluid chamber, it is possible to prevent the condensate flowing down from the condensate passage in the upper part of the second fluid chamber from blocking the condensate outlet in the lower condensate passage. can do.

Therefore, the condensing evaporator of the present invention is particularly suitable as a condensing evaporator of a large-scale air liquefaction separation apparatus with a large throughput,
The overall size of the device can be reduced, the operating power cost can be reduced, and the power unit of the product can be reduced.

[Brief description of drawings]

1 and 2 show an embodiment in which the condenser evaporator is arranged in the upper bottom space of the double rectification column, and FIG. 1 is a longitudinal sectional view showing the nitrogen chamber portion of the condenser evaporator. FIG. 2 is a longitudinal sectional view showing the oxygen chamber portion, and FIGS. 3 and 4 show an embodiment in which the condenser evaporator is arranged in the upper space of the lower column of the double rectification column. Is a vertical sectional view showing a nitrogen chamber portion of the condensing evaporator, FIG. 4 is a longitudinal sectional view showing an oxygen chamber portion of the same, and FIGS. 5 and 6 are upper column bottoms of the double rectification column of the conventional condensing evaporator. FIG. 5 is a vertical sectional view showing an oxygen chamber portion of the condenser / evaporator, and FIG. 6 is a vertical sectional view showing a nitrogen chamber portion of the same. 2 ... Oxygen chamber, 3 ... Evaporation flow path, 6 ... Upper tower, 13 ...
Lower tower, 20 …… Condensation evaporator, 21 …… Nitrogen chamber, 22 …… Side bar, 23 …… Gas inlet, 24 …… Condensate outlet, 25…
… Condensation channel, 26 …… Drainer, 27 …… Inlet header, 28
...... Outlet header, 30 …… Liquefied nitrogen reservoir, 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 49-37027 (JP, B1) JP-B 4-14269 (JP, B2) JP-B 6-68434 (JP, B2) Actual JP-61-42072 (JP, Y2) Actual public Sho 63-49676 (JP, Y2) Actual public Sho 63-47831 (JP, Y2)

Claims (4)

[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 condenser-evaporator that performs heat exchange, the substantially entire surfaces of both end portions of the second fluid chamber are opened, one opening is used as a gas inlet for introducing a gas fluid, and the other opening is used for condensing liquid. A condensation evaporator having a liquid outlet and a condensing passage having a downward gradient from the gas inlet to the condensate outlet in the horizontal direction. 2. The second fluid chamber is pressure-tightly sealed by covering the gas inlet and the condensate outlet at both ends with inlet and outlet headers, respectively, and connecting both headers to the gas fluid and condensate sides, respectively. The condensing evaporator according to claim 1, wherein the upper and lower ends of the first fluid chamber are opened, and the condensing evaporator itself is immersed in the liquid medium on the evaporating side. 3. The first fluid chamber has upper and lower end portions covered with outlet and inlet headers, respectively, and is hermetically sealed to connect both headers to the evaporative gas and the liquid medium side, respectively.
The condensing evaporator according to claim 1, wherein both ends of the second fluid chamber are opened, and the condensing evaporator itself is arranged in a gas fluid atmosphere on the condensing side. 4. The liquid draining portion is provided at a part of a condensate outlet port of the condensing passage of the second fluid chamber.
The condensation evaporator according to 2 or 3.