JPS63267877A - Condensing evaporator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a condensing evaporator that exchanges heat between a liquid medium in a first fluid chamber and a fluid in a second fluid chamber.

[Conventional technology]

Conventionally, a condensing evaporator used in the upper column of a double rectification column of an air liquefaction separation device is partitioned by a number of vertically parallel partition plates, and is divided into a first fluid chamber, (i! elementary chamber) and a second fluid chamber. A so-called plate-fin heat exchanger is used, in which double chambers (nitrogen chambers) are stacked alternately adjacent to each other, and the oxygen chambers are open at the top and bottom ends, and the oxygen chambers are open at the bottom of the upper column. The space is filled with liquid oxygen by being immersed in the liquid medium (liquid oxygen) that accumulates there. Then, heat exchange is performed with the nitrogen gas introduced into the nitrogen chamber from the lower column, so that the nitrogen gas is condensed to become liquid nitrogen, and the liquid oxygen is evaporated to become oxygen gas.

(Problems to be Solved by the Invention) However, since the oxygen chamber of a conventional condenser evaporator is immersed in liquid oxygen, the liquid temperature and boiling point rise (approximately 1°C/m) due to the liquid pressure at the depth of the liquid. The lower part of the condensing evaporator has a higher temperature than the upper part, which reduces the temperature difference with the condensing temperature of nitrogen.

Since the temperature difference between the nitrogen side and the oxygen side of the condensing evaporator is usually 1 to 2°C, the temperature rise of the liquid oxygen is a major problem in terms of the performance of the condensing evaporator.

That is, in order to operate the lower tower at 5 phantom f/1-jG,
Appropriate performance cannot be achieved unless the height of the condenser evaporator is set to approximately 2m.If the height of the condenser evaporator is increased to increase the capacity, the depth of the liquid acid thread will increase and the temperature of the liquid will rise. Therefore, the operating pressure of the lower column had to be increased, and the diameter of the column had to be increased to increase the number of bases, which made the manufacture of the column complicated.

In addition, the temperature increase due to the depth of liquid oxygen affects the operating pressure of the lower column. That is, the operating pressure of the lower column determines the condensation temperature of the saturated nitrogen gas at the top of the lower column, and in order to lower this condensation temperature, it is necessary to lower the temperature of liquid oxygen.

On the other hand, the power of the air separation device is the compression of the raw air, that is, the
Most of the energy is consumed in raising the pressure to the I column pressure, so if the lower column can be operated at a lower pressure, power costs can be reduced. However, in the conventional structure in which the condensing evaporator is immersed in liquid oxygen, there is a drawback in that the valve that increases the temperature of liquid oxygen by the liquid head always limits the reduction in the pressure of the lower column.

Furthermore, the capacity of the condenser-evaporator cannot be fully demonstrated unless liquid oxygen is stored in the space at the bottom of the upper column where the condenser-evaporator is installed. Since neither the condensate of liquid nitrogen nor the gas rising in the upper column due to evaporation of liquid oxygen is generated, the rectification action does not start, resulting in wasted time (start-up time).
During this time, there will be a loss in power costs.

The present invention eliminates geometrical restrictions in the height direction and enables the upper and lower bases of a rectification column for large-scale air separation equipment to be integrated into an integrated structure. It is an object of the present invention to provide a condensing evaporator that can reduce pressure to eliminate increases in liquid temperature and boiling point, reduce raw material air compression pressure to reduce power costs, and shorten start-up time.

[Means for solving problems]

In order to achieve the above object, the present invention alternately forms a first fluid chamber and a second fluid chamber by a large number of vertical partition plates, and the liquid medium in the first fluid chamber and the second fluid chamber are In a condensing evaporator that exchanges heat with a fluid, a plurality of heat transfer plates are arranged in upper and lower stages in the first fluid chamber to form a flow path for the liquid medium, one end of the flow path is open, and the other end is open. communicating with the flow path on the end side,
It is characterized in that a plurality of liquid reservoirs with open tops are provided in upper and lower stages, and a liquid medium is introduced into the flow path while being supplied to the liquid reservoirs in each stage for heat exchange.

[For production]

Therefore, it is possible to significantly reduce the rise in liquid temperature and boiling point due to liquid depth, and the height of the condenser evaporator can be increased to increase the heat transfer area, eliminating geometrical restrictions in the height direction and further increasing the startup time. can also be shortened.

[Example] Hereinafter, the present invention will be explained based on FIGS. 1 to 7 using oxygen as the liquid medium to be evaporated and nitrogen as the fluid to be condensed.

First, FIG. 1 is an overall perspective view of the condensing evaporator of the present invention, with a portion cut away to illustrate the internal structure of an oxygen chamber, which is a first fluid chamber. FIG. 2 is a sectional view showing the oxygen chamber, where the direction of flow of liquid is shown by solid arrows and the direction of gas flow is shown by dashed arrows.

The condenser evaporator 1 has upper and lower or both side pars 2.3
A first fluid chamber 5 (hereinafter referred to as an oxygen chamber) and a second fluid chamber 6 (hereinafter referred to as a nitrogen chamber) are formed by alternating a large number of Ia layers by a large number of vertically parallel partition plates 4 joined by. , heat exchange is performed between the liquid medium in the oxygen chamber 5 (hereinafter referred to as liquid oxygen LO) and the fluid flowing in the nitrogen chamber 6 (hereinafter referred to as nitrogen gas GN), and there are multiple liquids on the - side. 1f7
are arranged in multiple levels above and below.

The nitrogen chamber 6 is configured almost in the same way as a conventional device.
It is composed of a partition plate 4.4 and side pars 3.3 on both sides of the partition plate, and an inlet header 8 and an inlet pipe 9 for introducing nitrogen gas GN are provided in the upper part, and condensed liquid nitrogen LN is provided in the lower part. An outlet header 10 and an outlet pipe 11 for collecting the nitrogen gas GN, and a discharge pipe 12 for a non-condensable gas GX such as helium gas contained in the nitrogen gas GN are provided.

Nitrogen gas G distributed from the inlet header 8 to each nitrogen chamber 6
N is condensed and liquefied while exchanging heat with the liquid oxygen [0] in the adjacent oxygen chamber 5 and flows down inside the heat transfer plate 13 consisting of perforated wave-shaped heat transfer fins arranged vertically in the nitrogen chamber 6. , gather at the exit header-10.

On the other hand, the oxygen chamber 5, which is airtightly partitioned from the nitrogen chamber 6, is formed by a partition plate 4.4 and upper and lower side pars 2.2. One end of the flow path 14 is connected to the liquid reservoir 7.
The other end 14a is opened to serve as a gas outlet for oxygen gas Go.

The heat transfer plate 15 separates the partition plates 4.4, and although one plate may be used for each stage, corrugated heat transfer fins are usually used. In this embodiment, the heat transfer plate 15 uses corrugated heat transfer fins, and the bending line extends from the liquid reservoir 7 side to the flow path 1.
The heat transfer plates 15 are arranged vertically in multiple stages so as to have a slope toward the other end 14a of the heat exchanger plates 15, and a flow path 14 for liquid oxygen LO and oxygen gas GO is provided between the inclined surfaces of the upper and lower heat exchanger plates 15. , a plurality of upper and lower channels 14 communicate with one liquid 1fif7.

The liquids 17 arranged in multiple stages above and below are formed in a box shape with an open top, and the - side thereof is opened to the oxygen chamber 5 side to communicate with the flow path 14, and the liquid ff1f! of the lowest stage is formed. An overflow pipe 16 is provided except for 7a to allow the liquid acid IILO to flow down sequentially to the lower liquid M7, and the upper and lower adjacent liquid reservoirs 7 are disposed with an interval 17 between them.

This liquid reservoir is 7ft! The fl spacing 17 allows liquid oxygen LO
The pressure is released to the gas side of the oxygen chamber 5 in each liquid reservoir 7, so that the atmospheric pressure of liquid oxygen LO becomes the same in all stages, the liquid depth becomes small, there is almost no rise in ripples due to liquid pressure, and the condensing evaporator 1 It becomes possible to increase the

A part of the liquid oxygen 10 introduced into the uppermost liquid reservoir 7 flows into the flow path 14 and exchanges heat with the nitrogen gas GN flowing through the nitrogen chamber 6 in the adjacent room via the heat transfer plate 15 and the partition plate 4. Then, a part of it evaporates and becomes bubbles of oxygen gas GO, and liquid oxygen 1
After ascending the flow path 14 with 0, liquid oxygen LO at the end 14a
The liquid oxygen LO that is not evaporated flows downward.

In addition, the remaining liquid oxygen LO sequentially flows down to the lower liquid reservoir 7 through the overflow pipe 16 and flows into each flow path 14.
The liquid oxygen LO in excess of the amount flowing into each channel 14 overflows from the side wall of the lowermost liquid reservoir 7a and flows down.

The inclination angle of each channel 14 is determined by the depth of the connected liquid reservoir 7 and the channel 1.
4. Selection is made based on the length, etc. Although it is possible to provide the flow path 14 horizontally, it is better to provide the flow path 14 on an upward slope rather than horizontally so that the evaporated oxygen gas G is produced.

The floating blades make it easy for the bubbles to flow out of the channel 14, promoting the flow of liquid oxygen LO and increasing the heat transfer coefficient.

In the above embodiment, the flow path 14 is formed to have an upward slope, so that the bubbles of the evaporated oxygen gas Go flow into the liquid oxygen LO with the floating blades.
flows out from the other end 14a side. Therefore, the liquid oxygen 10 can be effectively evaporated and can be prevented from flowing down in vain, and the evaporated oxygen gas Go will not remain, thereby improving the efficiency of the condenser evaporator 1.

The amount of liquid oxygen LO flowing into each channel 14 is controlled by adjusting the liquid depth of the liquid reservoir 7, or by adjusting the channel length, inclination, or opening cross-sectional area of the channel 14.

Note that the uppermost channel 14b and the lowermost channel 14C are closed at one end, so the heat exchanger plate 15 in this part is the channel 1.
It is preferable to use a perforated plate or the like in which the four spaces are in communication to prevent the oxygen gas GO from stagnation.

The oxygen chamber 18 shown in FIGS. 3 and 4 (FIG. 4 is a view taken along the rV-IV arrow in FIG. 3) is located at the uppermost channel 14.
An example is shown in which a slant bar 19 is arranged to close the flow path 14c at the lowermost portion of the flow path 14b and communicate with the nitrogen chamber 6, thereby eliminating a stagnation portion of the oxygen gas GO.

In addition, the liquid reservoir 20 shown in FIGS. 3 and 4 has a 111
The side wall 20a having 21 is formed in the shape of an inverted trapezoid with 7 vertices, and the liquid oxygen LO flows down from the layer 21 to the lower liquid reservoir 20 in order. It receives pressure and releases pressure to the gas side, and has the same function as the overflow pipe 16 described above. In addition, when the slant bar 19 is arranged in the oxygen chamber as shown in FIG. 3, the means for overflowing the liquid reservoir 20 is not limited to the weir 21, and other methods may be used.

The oxygen chamber 22 shown in FIG. 5 shows another embodiment of the method of supplying liquid oxygen and O to the liquid reservoir. At the inlet side end of the liquid oxygen LO of the oxygen chamber 22, a liquid "1llff23" whose pressure is released to the gas side, similar to the aforementioned liquid reservoir, is provided in upper and lower stages in multiple stages. A liquid receiver 26 is provided at the upper end of the manifold pipe 24. By supplying the liquid oxygen LO to be supplied to the 6 liquid 123 to the liquid receiver 26, the manifold pipe 24. 31 to all liquid reservoirs 2 via the pipe 25
It can be distributed and supplied to 3. In order to prevent the amount of liquid supplied to each reservoir 23 from differing depending on the liquid head in the manifold pipe 24 and to distribute the amount evenly, the flow passage cross-sectional area of the communication pipe 25 is increased or decreased by the height of the liquid head. I'm letting you do it. By the above means, liquid oxygen LO whose boiling point does not increase due to the liquid head can be uniformly supplied to the oxygen chamber 22.

Of course, the liquid medium supply means to the liquid reservoir 23 may be configured by combining the overflow of the liquid reservoir 23 and the communication pipe 25.

Figures 6 and 7 show an example in which the aforementioned condenser evaporator 1 is installed in a double rectification column. The condenser evaporator on the left side of Figure 6 shows the oxygen chamber part, and the right side shows the nitrogen chamber part. 7 shows the Vl-vt cross section of FIG. 6. - The condensing evaporator 1 includes an upper column 31 and a lower column 3 of a double rectification column 30.
4 units are housed in parallel on the circumference centered on the nitrogen gas main pipe 34 on the partition plate 33 that partitions the two! iQ is located, oxygen chamber 5
The liquid reservoir 7 is open to the gas space 35 of the upper column 31.

A liquid reservoir 7.7 is provided between each condenser evaporator 1 and the nitrogen gas main pipe 340 and communicates with each stage, and a liquid oxygen introduction pipe 36 is inserted into the uppermost liquid reservoir 7.

Nitrogen gas GN is introduced into the nitrogen chamber 6 from each inlet header 8 through the nitrogen gas main pipe 34 from the top of the lower column 32, and is condensed and liquefied by exchanging heat with the liquid oxygen LO in the oxygen chamber 5, and then transferred to the outlet header 10. is collected and led out from the lower piping 37.

On the other hand, as described above, part of the liquid oxygen LO that has flowed from the bottom of the rectifying plate 38 of the upper column 31 through the introduction pipe 36 into the liquid reservoir 7 at the top of the condensing evaporator 1 flows into the oxygen chamber 5. It flows into the passage 14, exchanges heat with the nitrogen gas GN in the nitrogen chamber 6, and evaporates.
The oxygen gas GO becomes oxygen gas GO, flows through the channel 14, flows out from the end 14a, becomes the ascending gas in the upper column 31, and a portion is collected from the pipe 38 as the product oxygen gas Go.

Excess liquid oxygen LO that does not evaporate is stored at the end 14a of the flow path 14.
It flows down from the pipe 39 and accumulates on the partition plate 33, and is led out from the pipe 39. A part of it is collected as a product, and the other part is lifted up by a liquid oxygen pump or a thermosiphon-only boiler, and is returned to the liquid M7 from the pipe 40 at the top. is circulated.

As mentioned above, liquid oxygen LO flows into each flow path 14 from each liquid reservoir 7 and undergoes heat exchange, and further liquid oxygen LO flows down to the lower liquid reservoir 7 through the overflow pipe 16, The liquid flows down onto the partition plate 33 from the liquid reservoir 7a.

Further, in order to prevent liquid oxygen LO from completely evaporating in the oxygen chamber 5 and atyselene from precipitating in the flow path 14, it is preferable to constantly wash the flow path 14 with liquid oxygen LO by flowing an excess of liquid oxygen LO. In order to know that excess liquid oxygen LO is flowing down, the amount of liquid oxygen 10 accumulated on the partition plate 33 is measured by the liquid level gauge 41.

In this way, since the liquid oxygen is allowed to flow down, there is no rise in liquid temperature due to liquid pressure, and the condensation temperature of nitrogen gas can be lowered to reduce the operating pressure of the lower column, reducing the power cost of the raw air compressor.

Furthermore, since the height of the condensing evaporator can be increased and the heat transfer area can be increased, a device with higher capacity can be accommodated within the diameter of the rectifying column, making it easier to manufacture a double rectifying column.

Furthermore, since condensation and evaporation occur at the same time as the liquefied gas that has flowed down the upper column is introduced at the time of startup, startup time is significantly shortened and power costs during this time can be reduced.

Note that similar effects can be obtained when using other liquid media and fluids than evaporation and condensation through heat exchange between liquid oxygen and nitrogen gas in air liquefaction separation.

[Effect of appropriation]

As explained above, the present invention provides a first fluid chamber of a condensing evaporator in which heat exchange is performed between a liquid medium in a first fluid chamber and a fluid in a second fluid chamber, and a flow path is provided in upper and lower stages in multiple stages. At one end side, liquid reservoirs communicating with the flow path are provided in multiple stages above and below, and the liquid medium is introduced into the flow path and heat exchanged while being supplied to the liquid reservoirs at each stage, so that the liquid depth of the liquid medium is small. There is no temperature rise due to liquid pressure, the efficiency of the condensing evaporator is improved, the condensing temperature of the fluid in the second fluid chamber is lowered, and the operating pressure is reduced, thereby reducing power costs.

In addition, there are no restrictions on the shape of the condenser-evaporator in the height direction, making it possible to increase the throughput by making it longer. As a result, it became possible to make the diameter of the container housing the condensing evaporator the same as that of the rectification column, and even in the case of a rectification column for large-scale air separation equipment, it became possible to manufacture the upper and lower columns in an integrated structure.

Furthermore, since there is no need to immerse the device in a liquid medium, startup time can be shortened.

[Brief explanation of the drawing]

Figures 1 and 2 show an example of an actual droplet of the present invention. Figure 1 is a partially cutaway perspective view of the condenser evaporator, and Figure 2 is a perspective view of the oxygen chamber, which is the first fluid chamber. 3 and 4 show other embodiments of the present invention, in which FIG. 3 is a sectional view of the oxygen chamber, FIG. The figure is a sectional view of an oxygen chamber showing still another embodiment of the present invention, and Figures 6 and 7 are examples of using the condensing evaporator of the present invention in a double rectification column. FIG. 7 is a sectional view of the main part of the rectification column, and is a sectional view taken along the line Vl--Vl in FIG. 6. 1... Condensing evaporator 4... Partition plate 5... Oxygen chamber (first fluid chamber) 6... Nitrogen chamber (second fluid chamber)
7...Liquid reservoir 14...Flow path 15...Heat exchange plate 16...Overflow tube 24...Manifold tube GN...Nitrogen gas Go...Oxygen gas LN...Liquid nitrogen LO ...Liquid oxygen patent applicant Nihon Sanso Co., Ltd.

Claims (1)

[Claims] 1. First fluid chambers and second fluid chambers are formed alternately by a large number of vertical partition plates, and the liquid medium in the first fluid chamber and the fluid in the second fluid chamber are formed alternately. In a condensing evaporator that performs heat exchange,
A plurality of heat transfer plates are arranged in upper and lower stages in the first fluid chamber to form a flow path for the liquid medium, one end of the flow path is open, the other end communicates with the flow path, and the upper part is open. A condensing evaporator characterized in that a plurality of liquid reservoirs are provided in upper and lower stages, and a liquid medium is introduced into the flow path while being supplied to the liquid reservoirs in each stage for heat exchange. 2. The condensing evaporator according to claim 1, wherein the liquid medium flow path has an upward slope from one end on the liquid reservoir side to the tip of the other end.