JPH11316092A - Air-cooled heat exchanger and distillation apparatus using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air-cooled heat exchanger which has a high heat transfer efficiency, a simple structure, and can be reduced in size and weight, and a distillation apparatus using the same. SOLUTION: This is an annular heat exchanger 22 for cooling a process fluid A by air B serving as a cooling medium, and a plurality of rectangular heat transfer elements 31, 31. The gap in these heat transfer elements 31 is defined as a flow path 47 of the closed system process fluid A, and the heat transfer elements 31, 3
The gap between the two is defined as a flow path 48 of the air B of the open-to-atmosphere system, and the flow path 48 of the air B has a heat radiation functioning also as a spacer for maintaining a space between the heat transfer elements 31 forming the flow path 48. A member 33 is provided, and these heat transfer elements 31, 3
1,... Are formed by annular pressing members 34 and 35 disposed on the upper and lower sides and a winding member 39 wound on the outer periphery.
It is characterized in that the whole shape is held in a ring shape.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air-cooled heat exchanger and a distillation apparatus using the same, and more particularly, to an air-cooled heat exchanger having a high heat transfer efficiency, a simple structure, and a small size and light weight. The present invention relates to a distillation apparatus using the same.

[0002]

2. Description of the Related Art Conventionally, multi-tube heat exchangers are frequently used in air-cooled heat exchangers (condensers, liquid coolers) attached to distillation columns used in petroleum refining plants and petrochemical plants. However, conventional shell-and-tube heat exchangers
Since a large installation area and accompanying piping are required, there are problems such as a high manufacturing cost and a long construction period, which is disadvantageous. When the multi-tubular heat exchanger is to be installed at the top of a distillation column, its outer dimensions are large and its weight is also large. The method of stacking on a distillation column can hardly be incorporated.

In view of this, a structure in which this multi-tube heat exchanger is similarly reduced in size according to the size of the top of a distillation column to be incorporated can be considered. However, in this structure, the heat transfer area is also reduced. However, the heat transfer area is insufficient, and the pressure loss on the air side is large, so that there is a problem that the design is difficult.

As a structure in which a multitubular heat exchanger is incorporated at the top of a distillation column, for example, there is a top condenser disclosed in Japanese Patent Publication No. 49-15547. FIG. 8 is a partially cutaway plan view showing the overhead condenser 1, and FIG. 9 is a sectional view taken along the line AA in FIG. A certain fin tube bundle 2 is arranged in an equilateral polygon above the top cover 3a of the top 3, and the top 3
And coaxially adjacent to the top 3.

[0005] A vapor distribution chamber 4 above the tube bundle 2 is used for the top 3 and a condensate collecting chamber 5 below the tube bundle 2 is used for collecting condensate via an annular collection pipe 6 and a closing valve 7. Connected to the conduit 8 to be connected. In addition, a casing comprising a bottom plate 11 and a foot 12 for forced ventilation of cooling air, and at least one ventilator 13 are provided. Also,
An autovapor riser pipe 14 having an outer diameter considerably smaller than the tower top 3 and derived from the top cover 3a has an autovapor distribution pipe 15 extending from the upper end thereof.

The distribution pipe 15 runs almost linearly,
It extends substantially horizontally beyond the periphery of the tower top 3 radially with respect to the autovapor riser 14, and forms a support structure for the condenser 1 together with the autovapor riser 14. In this case, each of the auto vapor distribution pipes 15 has a branch pipe 16 corresponding to the number of the fin tube bundles 2 connected and fixed to the end opposite to the auto vapor riser pipe 14.
Are all arranged in one plane.

In this overhead condenser 1, a ventilator 13
9 faces the internal space of the condenser 1. In FIG. 9, an arrow X indicates fresh air introduced from outside, and an arrow Y indicates exhaust air discharged from the internal space of the condenser 1. The overhead condenser 1 is particularly suitable for condensing a medium having a small temperature difference with respect to the cooling air flowing in.

Further, as another type of heat exchanger for solving the problems of the conventional air-cooled heat exchanger, there is a plate-fin type heat exchanger used in a distillation column of an ethylene unit or a cryogenic air separation unit. There are heat exchangers and gasket type plate heat exchangers.

[0009]

In the above-mentioned conventional overhead condenser, the external dimensions and weight are very large, so special conditions are required to support the external dimensions and weight. There is a problem that it can be applied only to a distillation column having a large diameter with respect to the height, such as a vacuum distillation apparatus provided.

Further, when the above-mentioned plate fin type heat exchanger is used as an air-cooled heat exchanger, the pressure loss on the air side is large, the blower fan power is excessive, and the size is limited from the viewpoint of manufacturing. However, this heat exchanger is cost-effective due to its high price unless both fluids are clean liquid and its vapor and the operating temperature is not under special conditions of minus several tens of degrees Celsius or less. Absent.

Further, when the gasket type plate heat exchanger described above is used as an air-cooled heat exchanger, the flow passage areas of the process fluid (top product) and the air cannot be freely taken. The pressure loss on the air side is large,
In addition, there is a problem that the weight of the end plate to which the heat transfer plate is fastened is large, and it is disadvantageous to incorporate the end plate into the top of the distillation column.

The present invention has been made in view of the above circumstances, and provides an air-cooled heat exchanger having a high heat transfer efficiency, a simple structure, a small size and a light weight, and a distillation apparatus using the same. The purpose is to provide.

[0013]

In order to solve the above-mentioned problems, the present invention provides the following air-cooled heat exchanger and a distillation apparatus using the same. That is, the air-cooled heat exchanger according to claim 1 of the present invention is an annular heat exchanger that cools a process fluid by air serving as a cooling medium, and a plurality of rectangular plate-shaped heat transfer members The heat transfer members are arranged in an annular shape such that the main surfaces thereof face in the circumferential direction, and the respective gaps formed between these heat transfer members are used as flow paths. The flow path and the air flow path of the open air system are alternately arranged, and the air flow path is provided with a heat radiating member also serving as a spacer for maintaining an interval between the heat transfer members forming the flow path. The heat transfer members are arranged in the form of a ring, and the entire shape thereof is held in an annular shape by annular holding members arranged vertically and winding members wound around the outer periphery.

According to a second aspect of the present invention, there is provided the air-cooled heat exchanger according to the first aspect, wherein the annular holding member disposed above the heat transfer member is a distribution pipe for supplying a process fluid. Wherein the annular holding member provided below the heat transfer member is a cooled process fluid recovery pipe.

According to a third aspect of the present invention, there is provided an air-cooled heat exchanger according to the first or second aspect, wherein the heat radiating member is a coiled number wire in which a good heat transfer wire is spirally wound. It is characterized by:

According to a fourth aspect of the present invention, in the air-cooled heat exchanger according to the first, second or third aspect, the pair of heat transfer members forming the fluid flow path are formed of a rectangular plate. The part is bent so that both ends thereof overlap, and the both ends are air-tightly connected.

A distillation apparatus according to a fifth aspect is characterized in that the air-cooled heat exchanger according to the first, second, third or fourth aspect is provided at the top of the distillation column.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of an air-cooled heat exchanger and a distillation apparatus using the same according to the present invention will be described with reference to the drawings. FIG. 1 is a front view showing a distillation apparatus according to one embodiment of the present invention. In the figure, an air-cooled heat exchanger 22 is provided on a pedestal (not shown) at the top 21 a of a distillation column 21. The heat exchanger 22 includes a pipe 23 that supplies a process fluid A that is a gas of a top product, and a process fluid A ′ that is a liquid obtained by cooling and condensing the process fluid A.
Is connected to the top 21a of the distillation column 21 by a pipe 24 for refluxing to the top 21a.
Serves also as a support structure for holding the air-cooled heat exchanger 22 on the tower top 21a.

A vessel (shelf plate with overflow) 25 for storing the process fluid A ', which is a liquid from the pipe 24, is provided in the top 21a of the distillation column 21. In the vessel 25, the process fluid A ′ is charged with the distillation column 21.
A pipe 27 provided with a control valve 26 for extracting a part from the pipe is connected. This distillation apparatus is operated under the condition that the process fluid A ′ overflows a certain amount from the vessel 25.

In the air-cooled heat exchanger 22, as shown in FIGS. 2 to 4, a plurality of rectangular heat transfer elements 31 are arranged such that the main surfaces 31a of these heat transfer elements 31 face in the circumferential direction. A plurality of coils, which are heat dissipating members having a small flow path resistance and also serving as spacers for promoting heat transfer and maintaining the space between the heat transfer elements 31, are disposed between the heat transfer elements 31 in a ring shape as described above. Model number lines 32, 32, ...
Are provided, and further, a partition bar 33 for connecting the upper end portions of the heat transfer elements 31 and 31 in an airtight state is provided. In the above, the coiled number lines 32, 3
The width of each of the partition bars 33 is reduced toward the center of the ring.

Heat transfer element 3 disposed in a ring shape
Are vapor headers (pressing members) 34 which are distribution pipes for supplying a process fluid having a semicircular cross section obtained by dividing an annular pipe disposed at the upper part of the air-cooled heat exchanger 22 into two parts.
And a condensate header (pressing member) 35, which is a process fluid recovery pipe having a semicircular cross section obtained by dividing an annular pipe disposed in the lower part into two parts. A fan 36 for forcibly ventilating the air B serving as a cooling medium to the outside is provided via a shaft 37, a motor, and a speed reducer 38.

The air-cooled heat exchanger 22 has a vapor header 34 as an upper pressing member, a condensate header 35 as a lower pressing member, and a stiffener ring (wound member) 39 wound around the outer periphery. Is held in an annular shape.

The vapor header 34 has a half-section inside in which a distribution channel for the process fluid A is provided.
3 is connected. The condensate header 35
The inside of the half-section cross section is a flow path for the liquefied process fluid A ′, and is connected to the pipe 24.

As shown in FIG. 5, the heat transfer element 31 is formed by bending a rectangular plate member 41 made of a heat conductive material such as stainless steel or aluminum so that both end portions 42 and 43 thereof overlap. Both ends 42 and 43 are connected so as to be airtight by welding. Then, respective surfaces 41a, 41 of the plate member 41 bent into two.
b, a plurality of protrusions 44 for maintaining the interval between these surfaces 41a and 41b are formed so as to face each other, End pieces 45 and 4 that also serve as reinforcement
6 is fixed by welding.

In the heat transfer element 31, the gap formed between the surfaces 41a and 41b is
Channel 47. A gap formed between these heat transfer elements 31, 31,... Arranged in the circumferential direction serves as an air release system for a flow path 4 of air B serving as a cooling medium.
8 is set.

In this distillation apparatus, the gaseous process fluid A generated in the distillation column 21 is introduced into the vapor header 34 of the air-cooled heat exchanger 22 through the pipe 23 connected to the top 21a. The heat is distributed and supplied into the channels 47 of the heat transfer elements 31 arranged while flowing in the vapor header 34 in the circumferential direction.

On the other hand, air B serving as a cooling medium is introduced into the flow path 48 between the heat transfer elements 31, 31,... By the fan 36, and the surfaces of the heat transfer elements 31, 31,. Cooling is also performed via the serial number lines 32, 32,. Thereby, the heat transfer elements 31, 3
The process fluid A, which is a gas in 1, ..., is cooled, condensed, and liquefied. The liquefied process fluid A ′ passes through the condensate header 35 and the pipe 24 and passes through the top 21
The liquid is returned to the vessel 25 in a, and a part of the liquid is refluxed into the distillation tower 21, and a part of the liquid is extracted from the distillation tower 21 via the control valve 26 and the pipe 27.

In the air-cooled heat exchanger 22 of the present embodiment, an example is shown in which coiled wires 32, 32,... Are provided between the heat transfer elements 31, 31 as heat dissipating members also serving as spacers. However, the heat dissipating member also serving as a spacer may be any heat dissipating member as long as it has heat conductivity, has a small air flow path resistance, and has a function of maintaining a space between the heat transfer elements 31, 31. For example, FIGS.
As shown in FIG. 5, a pipe 50 made of a good heat transfer material may be vertically divided into two to form a gutter shape.

Since the coiled wire 32 can have a very low flow resistance as compared with a generally used spacer and is not rigid but deformable,
There is a feature that the degree of freedom in installation is large, for example, a manufacturing error and stress between the heat transfer elements 31 and 31 can be absorbed, and furthermore, the arrangement density can be freely changed.
On the other hand, when the rigidity of the overall shape of the air-cooled heat exchanger 22 is insufficient, the rigidity can be improved by applying a rigid heat dissipating member such as the above-described half pipe 50.

In this embodiment, the above-mentioned plate-type heat transfer elements 31, 31,... Are arranged in an annular shape, so that the end plate conventionally required for a general plate-type heat exchanger can be used. Since it becomes unnecessary, weight reduction can be achieved and heat transfer density can be increased.

As described above, according to the distillation apparatus of the present embodiment, the air-cooled heat exchanger 2 is mounted on the top 21a of the distillation column 21.
2, the installation space required for the air-cooled heat exchanger 22 is not required, and the auxiliary piping may be short, the manufacturing cost can be reduced, and the construction period can be shortened. In addition, since the air-cooled heat exchanger 22 can be manufactured and installed together with the distillation tower 21, a step of independently installing the heat exchanger itself is not required, and the manufacturing cost and the construction period can be further reduced.

Also, a plurality of rectangular heat transfer elements 3
1 are arranged in an annular shape such that the main surfaces 31a face in the circumferential direction, so that the conventional multi-tube heat exchanger, plate-fin heat exchanger, gasket-type plate heat exchanger can be simply constructed. The heat transfer efficiency can be increased as compared with the above.
Therefore, miniaturization and weight reduction can be achieved for the same heat exchange capacity.

Further, the contact area of the process fluid A with the air B can be increased, and the cooling efficiency can be improved. Further, since the area of the flow path 48 on the air B side can be arbitrarily set, the pressure loss on the air B side can be reduced.

[0034]

As described above, according to the air-cooled heat exchanger of the present invention, a plurality of rectangular plate-like heat transfer members are formed such that the main surfaces of these heat transfer members face in the circumferential direction. The gaps formed between these heat transfer members are used as flow paths, and these flow paths are a flow path of a closed process fluid and a flow path of an open air air. Are alternately arranged, so that the heat transfer efficiency can be increased as compared with the conventional heat exchanger. Further, since the configuration is simple, reduction in size and weight can be achieved.

In the distillation apparatus of the present invention, the air-cooled heat exchanger of the present invention is provided on the top of the distillation column, so that a unique installation area of the heat exchanger is not required, and a mounting stand and ancillary equipment are not required. Piping can also be reduced, manufacturing costs can be reduced, and the construction period can be shortened. In addition, since the air-cooled heat exchanger can be manufactured and installed together with the distillation tower, a process of independently installing the heat exchanger itself is not required, thereby further reducing the manufacturing cost and shortening the construction period.

[Brief description of the drawings]

FIG. 1 is a front view showing a distillation apparatus according to an embodiment of the present invention.

FIG. 2 is a perspective view showing an air-cooled heat exchanger according to one embodiment of the present invention.

FIG. 3 is an exploded perspective view showing an air-cooled heat exchanger according to one embodiment of the present invention.

FIG. 4 is a partially broken plan view showing an air-cooled heat exchanger according to one embodiment of the present invention.

FIG. 5 is a view showing a heat transfer element of an air-cooled heat exchanger according to one embodiment of the present invention, where (a) is an exploded perspective view,
(B) is a perspective view showing the entire configuration.

FIG. 6 is a partially exploded side view showing a modification of the air-cooled heat exchanger according to one embodiment of the present invention.

FIG. 7 is a sectional view taken along the line BB of FIG. 6;

FIG. 8 is a partially broken plan view showing a conventional overhead condenser.

FIG. 9 is a sectional view taken along line AA of FIG. 8;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Top condenser 2 Fin tube bundle 3 Top 3a Top cover 4 Steam distribution chamber 5 Condensate collection chamber 6 Annular collection pipe 7 Closure valve 8 Conduit 11 Bottom plate 12 Hood 13 Ventilator 14 Auto vapor riser 15 Auto vapor Piping 16 Branch pipe 21 Distillation tower 21a Top 22 Air-cooled heat exchanger 23 Piping 24 Piping 25 Vessel 26 Control valve 27 Piping 31 Heat transfer element 31a Main surface 32 Coiled wire 33 Partition bar 34 Vapor header (pressing member) 35 Condensate Header (pressing member) 36 Fan 37 Shaft 38 Motor and reduction gear 39 Stiffening (winding member) 41 Plate member 41a, 41b surface 42, 43 end 44 Protrusion 45, 46 End piece 47 Process fluid flow path 48 Air Flow path 50 half pipe (radiation Exhaust air discharged from the fresh air Y condensers internal space introduced from the process fluid B air X outside of the process fluid A 'liquid timber) A gas

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yasuo Suzuki 2205 Narita-cho, Oarai-machi, Higashiibaraki-gun, Ibaraki Pref.

Claims (5)

[Claims] 1. An annular heat exchanger for cooling a process fluid by air serving as a cooling medium, wherein a plurality of rectangular plate-shaped heat transfer members are arranged such that main surfaces of each of the heat transfer members are arranged in a circumferential direction. Each of the gaps formed between these heat transfer members is a flow path, and these flow paths are a flow path of a closed system process fluid and a flow path of an air open system. A flow path and a heat radiating member serving also as a spacer for maintaining an interval between the heat transfer members forming the flow path are provided in the air flow path, and these heat transfer members are An air-cooled heat exchanger characterized in that the entire shape is held in an annular shape by annular holding members arranged on the upper and lower sides and a winding member wound around the outer periphery. 2. An annular pressing member disposed above the heat transfer member is a process fluid supply distribution pipe, and the annular pressing member disposed below the heat transfer member is cooled. The air-cooled heat exchanger according to claim 1, wherein the pipe is a collection pipe for process fluid recovery. 3. The air-cooled heat exchanger according to claim 1, wherein the heat dissipating member is a coiled number wire formed by spirally winding a good heat transfer wire. 4. The pair of heat transfer members forming the fluid flow path are formed by bending a rectangular plate portion so that both ends thereof overlap, and connecting both ends in an airtight manner. The air-cooled heat exchanger according to claim 1, 2, or 3. 5. A distillation apparatus comprising the air-cooled heat exchanger according to claim 1, provided on the top of the distillation tower.