JPH01199601A - Evaporator - Google Patents

Abstract

PURPOSE:To improve the heat transmission of an annular heat exchanger by increasing the pumping action caused by the rotation of a screw-type spiral heat exchanger by the annular heat exchanger set on the outside of the spiral heat exchanger. CONSTITUTION:The screw-type heat exchanger 1, a part of which is placed under the level L of the liq. to be heated in an evaporation boiler 12, is horizontally or slantly set in the boiler 12 so that a passage for a heating medium is formed in the boiler 12. The heat exchanger 1 is rotated around the screw shaft 4 by driving gears 19-22. The annular heat exchanger 13 is set around the heat exchanger 1. A rotor 17 extending in the axial direction of the shaft 4 and fixed to the shaft 4 is arranged in the space between the heat exchanger 13 and the inner wall of the boiler 12. As a result, the deposition of the solid matter, fibers, etc., in the liq. to be heated on the heat exchangers can be prevented, a decrease in the efficiency of the heat exchangers is obviated, and the need for the cleaning of the heat exchangers in a short time is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an evaporator for chemical solutions, food waste liquids, etc., and particularly to an evaporator suitable for concentrating alcoholic distillation waste liquids.

[Conventional technology]

Figure 5 shows an evaporative concentration system using multiple-effect cans that is currently in practical use. That is, the concentrator is composed of heat exchangers 41 A and 41 connected to the first stage evaporator 45 and each subsequent evaporator 45, respectively, and a plurality of concentrators are connected in series as shown in FIG. It is located in Only the first-stage concentrator to which the concentrate is supplied from the concentrate tank 46 is heated by external steam, and the subsequent second, third, etc. cans are each drawn to a higher degree of vacuum than the previous-stage concentrator. This shows a known method of recovering steam energy for heating. In this way, heated steam is supplied from the outside to the heat exchanger 41A of the first concentrator to heat the liquid, and in subsequent concentrators,
Steam generated in the preceding evaporator 45 is applied to the next-stage heat exchanger 41 connected to each evaporator 45 .

The heat exchangers 41A, 41 are generally externally arranged heat exchangers as shown in the figure, which have a large area and a high heat transmission coefficient in order to increase system efficiency. Further, in order to circulate the fluid to be heated in the heat exchangers 41A and 41, a circulation pump 42 is used to force suction and circulation.

43 is a vacuum pump that sucks condensate and maintains a vacuum, and 44 is a feed pump that sends the fluid to be heated to the subsequent concentrator.

In addition to this known multiple effect can system, a single can vapor reflux system shown in FIG. 6 has also been put into practical use. That is, the vapor generated in the evaporator 56 containing the stock solution sent by the pump 59 from the stock solution tank group is compressed by the evaporator compressor 57 to raise the condensation temperature, and then the stock solution flows inside the tube by the circulation pump 52. A system in which the concentrated liquid is concentrated by flowing it into the heat exchanger 51 for heat exchange and sending the concentrated liquid between storage tanks has also been put to practical use and is well known.

However, these methods have the following disadvantages.

(1) When heating a fluid containing solids, fibers, etc. such as alcohol waste liquid, the efficiency of the heat exchanger decreases in a relatively short period of time as the solids adhere to the heat exchanger. Tend.

(2) Therefore, it is necessary to clean the heat exchanger in a relatively short period of time, and it is also necessary to treat the cleaning liquid.

(3) In the circulation pump (42, 52), the suction fluid is at a saturation temperature where liquid and vapor coexist, and if the pressure is reduced by the pump's suction, boiling will immediately occur at the pump suction section, resulting in a sudden drop in suction efficiency. causes a significant decrease. In order to avoid such boiling under reduced pressure, a method is often used in which the circulation pump is placed 2 to 3 rr below the bottom of the evaporator and the head pressure compensates for the reduced pressure. This makes it difficult to arrange the devices on the same plane, which hinders the packaging and miniaturization of the devices.

(4) The power consumption of the heat exchanger circulation pump increases rapidly as the viscosity of the heated fluid increases, deteriorating the energy efficiency, and the biggest factor that determines the limit of concentrated concentration is the bomb pink limit for highly concentrated fluids. It is often decided.

In order to solve the problems in paragraphs (3) and (4) above, the seventh
As shown in the figure, there is also a known method in which a heat exchanger 61 is disposed inside an evaporator 62 and an agitator head driven by a motor 63 that stirs the fluid to give it flow is built into the evaporator 62. be. However, this method also has the following disadvantages and cannot be a solution to the methods shown in FIGS. 5 and 6.

That is, (al) Concentration capacity is small because sufficient heat transfer area is not taken.

[b+ This method cannot avoid the disadvantage of the method shown in FIGS. 5 and 6 above that the heat transfer surface becomes dirty, so the problems 11) and +21 above are still unsolved.

[Problem to be solved by the invention]

The present invention seeks to solve the drawbacks described in connection with the prior art systems in the "Prior Art" section above.

In other words, the evaporator prevents solid matter, fibers, etc. contained in the liquid to be heated from adhering to the heat exchanger, prevents the efficiency of the heat exchanger from decreasing, and does not require cleaning the heat exchanger in a short period of time. This is what we are trying to provide.

Furthermore, the present invention aims to provide an evaporation device that is small, consumes little power, and is suitable for high-viscosity fluids by omitting a heat exchanger circulation pump for the liquid to be heated.

[Means to solve the problem]

In the evaporator of the present invention, a screw-shaped spiral heat exchanger whose inside forms a heat medium passage is arranged in the evaporator with its screw axis horizontal or inclined,
A portion of the heat exchanger was positioned below the surface of the liquid to be heated in the evaporator, and the heat exchanger was rotated around the screw shaft by a drive device. An annular heat exchanger surrounding the spiral heat exchanger was installed outside the spiral heat exchanger. A rotating body extending in the axial direction of the screw shaft, fixed to the screw shaft, and rotating together with the screw shaft was installed in a space sandwiched between the annular heat exchanger and the inner wall of the evaporator.

[Effect]

The present invention has the following effects.

(1) A screw-shaped spiral heat exchanger, a part of which is below the surface of the liquid to be heated, rotates, imparting a relative speed to the liquid and causing the liquid to move due to the slope of the spiral surface. Heat transfer can be improved by generating pressure, which cleans the heat transfer surfaces of the spiral heat exchanger and agitates the fluid.

(2) A screw-shaped spiral heat exchanger is rotated around the screw shaft inside the evaporator, and its pumping action causes the liquid in the evaporator to circulate between the inside and outside of the annular heat exchanger. It creates a strong circulation flow and improves the heat transfer of the annular heat exchanger.

(3) By rotating the screw-shaped spiral heat exchanger and rotating body at an appropriate driving speed, even if the liquid in the evaporator has a high viscosity, the pumping action that sucks and sends out the liquid can be achieved. You can have it. This makes it possible to heat and concentrate highly concentrated and highly viscous liquids.

(4) By installing a screw-shaped spiral heat exchanger in the evaporator in a horizontal or inclined state, the shape of the heat exchanger and evaporator can be made horizontally elongated and the evaporation area can be increased. It becomes possible.

(5) A part of the heat transfer surface of the screw-shaped spiral heat exchanger is below the liquid level, and the other part is exposed to the evaporation space in the evaporator. By rotating, the heat transfer surface of the heat exchanger moves alternately between the heated liquid and the evaporation space, so that the heated liquid forms a thin film on the spiral heat transfer surface of the heat exchanger. , a thin film evaporation of the liquid to be heated occurs, and heat transfer performance is improved.

(6) The rotation of the rotating body transports the liquid to be heated to the upper part of the annular heat exchanger, and the heated liquid becomes a thin film and flows down the surface of the annular heat exchanger, exchanging heat. Thin film evaporation of the heated liquid is performed [improves heat transfer performance].

〔Example〕

An embodiment of the present invention is shown in FIGS. 1 and 2.

Reference numeral 1 denotes a spiral heat exchanger arranged horizontally, in which a continuous spiral passage 3 is formed inside a screw-shaped spiral member 2, and the outer surface of the spiral member 2 forms a heat transfer surface. is forming. Reference numeral 4 denotes a shaft provided at the center of the heat exchanger, to which the spiral member 2 is attached, one end 5 of which has a plurality of heat medium inlet holes 6 opened laterally, and the other end. 7 is provided with a heat medium outlet hole 8 passing through the same end. The shaft 4 has a hollow structure, and a heat medium inlet chamber 10 communicating with the heat medium inlet hole 6 and a heat medium outlet chamber 11 communicating with the heat medium outlet hole 8 are formed by the partition plate 9 .

Further, one end of the spiral passage 3 communicates with the heat medium inlet chamber 10, and the other end communicates with the heat medium outlet hole 8 via the heat medium outlet chamber 11.

As shown in FIG. 1, this heat exchanger 1 is horizontally attached to an evaporator 12 so as to be rotatable around a shaft 4, and a lower part of the heat exchanger 1 is connected to the liquid to be heated in the evaporator 12. It is placed below the liquid level. One end 5 and the other end 7 of the heat exchanger protrude outside the evaporator 12 .

13 is an annular heat exchanger extending in the direction of the axis 4.

This annular heat exchanger 13 is arranged at a distance on the outside of the spiral member 2, and has an annular heat medium exchange chamber 14 that communicates with the heat medium inlet hole 15 and is continuous in the circumferential direction. It is formed from a heat medium outlet hole 16 communicating with the chamber 14 .

In the space between the annular heat exchanger 13 and the inner wall of the evaporator 12, there is provided an annular scraper-shaped scraper which extends over the entire length of the annular heat exchanger 13 in the direction of the axis 4 and has a plurality of through holes 17'. A rotating body 17 is provided, and the rotating body 17 is attached to the shaft 4.

18 is a steam outlet provided at the top of the evaporator.

A boo I719 is attached to one end 5 of the shaft 4,
The pulley 19 is connected to the motor n which is the drive machine via the
It is designed to be driven by a pulley 21 of.

The evaporator 12 is located at a position corresponding to the heat medium inlet hole 6.
The heat medium inlet is connected to a heat medium source (not shown).

The evaporator 12 is also provided with a supply port and a discharge port (not shown) for the liquid to be heated, and accommodates the liquid to be heated having the liquid level shown in FIG.

In this embodiment, the heat medium is passed through the heat medium inlet device, the heat medium inlet hole 6, the heat medium inlet chamber 10, and the spiral member 20.
At the same time, the heat exchanger 1 is rotated around the shaft 4 by starting the motor n.

The heat medium flowing through the passage 3 of the heat exchanger 1 exchanges heat with the liquid to be heated in the evaporator 12 via the spiral member 2 to heat and evaporate the liquid. Water is discharged from the heat medium outlet hole 8 of the other end 7 of the shaft 4.

Further, the heat medium is introduced into the annular heat exchanger 13 through the heat medium inlet hole 15, and heat exchanges with the liquid to be heated in the evaporator 12 to heat and evaporate the liquid, while the heat medium is condensed. The resulting condensate is discharged from the heat medium outlet hole 16.

Gas evaporated from the heated liquid is discharged from the vapor outlet 18.

As the screw-shaped heat exchanger l rotates within the liquid to be heated in the evaporator 12, a relative velocity with the liquid to be heated is generated, and dynamic pressure is generated in the liquid to be heated due to the inclination of the spiral surface. This makes it possible to improve heat transfer by cleaning the outer surface of the spiral member 2, which is a heat transfer surface, and stirring the liquid to be heated.

An annular heat exchanger 13 located outside the heat exchanger 1 and surrounding the same heat exchanger 1 increases the pumping action caused by the rotation of the screw-shaped spiral member 2 in the evaporator 12, and increases the unit volume. The heat exchange area per area is increased.

In the evaporator 12, a strong circulation flow occurs in the liquid to be heated from the space around the spiral member 2, through the gap space between the circular tubular heat exchanger 13 and the evaporator 12, and back to the space around the spiral member 2, and heat is generated as a whole. Improves communication. A rotating body 17 attached to the shaft 4 stirs the liquid to be heated in the gap between the annular heat exchanger 13 and the evaporator 12, and at the same time directs the liquid to be heated into the upper part of the tubular heat exchanger 13. This action increases the effective heat transfer area of the heat exchanger 13 and improves heat transfer.

The evaporator 12 is rotated by the spiral member 2 and the rotating body 170 times.
Stirring and mixing of the liquid to be heated inside is promoted, and it is possible to heat and evaporate a highly concentrated and highly viscous liquid.

Furthermore, in the heat exchanger 1 in this embodiment, the - part is located below the level of the liquid to be heated in the evaporator 12, and since this rotates around its axis 4, it is the heat transfer surface. The outer surface of the spiral member 2 moves alternately between the inside of the heated liquid and the evaporation space above the liquid level. As a result, the liquid to be heated is formed into a film on the heat transfer surface of the outer surface of the spiral member 2 in the evaporation space, and the liquid to be heated is evaporated into a thin film, improving heat transfer performance.

Further, the rotating body 17 transports the liquid to be heated to the upper part of the annular heat exchanger 13, and the liquid to be heated becomes a thin film and flows down the surface of the heat exchanger 130, and heat exchange is performed. Thin film evaporation of the heated liquid is performed, improving heat transfer performance.

Moreover, in this embodiment, since the heat exchanger 1 is arranged horizontally, the necessary heat transfer area can be expanded without increasing the height of the evaporator 12.

FIG. 3 shows another embodiment of the invention.

This embodiment has the same structure as the embodiment shown in FIGS. 1 and 2 except for the following points. That is, in this embodiment, a plurality of partition plates extending in the axial direction of the heat exchanger 13 are provided inside the annular heat exchanger 13. A plurality of partition plates S1 of one group of partition plates extend from the side wall 13' where the heat medium inlet hole 15 and the heat medium outlet hole 16 of the heat exchanger 13 are provided toward the other side wall 13'' of the heat exchanger 13. A space is provided between the side wall 13'' and the end of the partition plate S1. The partition plate S2 of the other group is connected to the other side wall 13'' of the heat exchanger 13.
It extends from the side wall 13' toward the side wall 13' where the heat medium inlet hole 15 and the heat medium outlet hole 16 are provided, and a space is provided between the end thereof and the side wall 13'. Such a partition plate S1
．． S2 are each placed adjacent to each other as shown in FIG.

In this embodiment, the heat medium entering the annular heat exchanger 13 from the inlet hole 15 is transferred to the partition plate S1. The water flows in a zigzag pattern in the passage formed by S2 and flows out from the outlet hole 16. As a result, the length of the flow path through which the heat medium flows is increased, heat exchange is performed over the entire surface of the annular heat exchanger 13, and its efficiency is increased.

FIG. 4 shows another embodiment of the invention in the UK. In this example,
m similar to the embodiment shown in FIG. 1 and FIG. 2 or FIG. 3 above.
A spiral-faced heat exchanger 1 is rotatably mounted horizontally within an evaporator 12. The motor n rotates the shaft 4 through the pulley 21, the bell 20, and the pulley 19 in the same manner as in the above embodiment.

Furthermore, an 11-piece annular heat exchanger 13 and a rotating body 17 similar to the embodiment shown in FIGS. 1 and 2 are provided.

Sae is a stock solution tank, and the stock solution to be heated is supplied to the upper part of the evaporator 12 through piping by the stock solution delivery pump 5, and the liquid level is the stock solution that is heated by a part of the heat exchanger 1. It is set to be within.

The evaporator 12 has a vapor outlet 1 connected to the gas-liquid separator 4.
8 is provided, and the vapor separated from the liquid by the gas-liquid separator n is
The steam section, which is pressurized by the compressor section driven by the drive machine and whose temperature at the time of condensation is increased, is passed through the pipe 30. The heat medium flows through the heat medium inlet n, the heat medium inlet hole 6, and the heat medium inflow chamber 10 into the passage 3 of the heat exchanger 1 as a heat medium.

A condensate discharge pipe 32 is connected to the heat medium outlet hole 8 of the other end 7 of the shaft 4.
is connected.

In addition, a part of the steam that has been pressurized by the compressor section and has a higher steam temperature at the time of condensation is condensed through heat exchange in the pipe 31, the heat medium inlet hole 15, and the heat medium exchange chamber 14, and is then condensed at the heat medium outlet. hole 16
The condensate is discharged from the condensate discharge pipe connected to the condensate.

The lower part of the evaporator 12 is connected to a concentrate tank via a concentrate delivery pump. Further, a pipe 36 that communicates with the lower part of the evaporator 12 is opened at the bottom of the steam/water separator τ, and the liquid separated by the steam/water separator τ is returned to the evaporator 12 again. .

This embodiment with the above configuration uses a mechanical vapor recompression method (MechanicaIVapor Recompression method).
This method is related to a method called MVR method (abbreviated as MVR method). The heated liquid supplied from the raw liquid tank to the evaporator 12 generates steam through heat exchange with the heat exchanger 1 in the evaporator 12, and this steam is pressurized in the compressor section to produce steam during condensation. Increase temperature. The steam is transferred to the above-mentioned pipes, heat medium loss, heat medium inlet hole 6, and heat medium inlet chamber 10.
through the passage 3 of the heat exchanger 1 in the evaporator 12 and the pipe 31
, into the heat medium exchange chamber 14 through the heat medium inlet hole I5,
The liquid inside the can is heated. In this embodiment, the heat of the vapor vaporized in the evaporator 12 is recovered and reused for heating, making it possible to save energy to a large extent.

Further, the heat exchanger 1 is driven by a motor n to rotate around a shaft 4 within the evaporator 12, and a strong internal circulation flow is formed in the liquid within the evaporator. Evaporator 1 with heat exchanger 1
The heating evaporation of the liquid in evaporator 12 is as described above.
The steam generated is compressed in the compressor section and reused as described above. Further, condensate water generated as a result of heat exchange in the heat exchanger 1 is taken out from the condensate discharge pipe 32 through the heat medium outlet hole 8 .

In addition, condensate water produced as a result of heat exchange in the annular heat exchanger 13 passes through the heat medium outlet hole 16 and is taken out from the condensate discharge pipe 33. The heated and evaporated concentrated liquid is discharged from the lower part of the evaporator 12 to the concentrated liquid tank A by the concentrated liquid delivery pump A.

In this embodiment, the input energy is the drive unit that drives the compressor unit and the motor η that rotates the heat exchanger 1. Evaporation is continued by driving the compressor section and heat exchanger 1. However, in this embodiment, only at startup,
Although a heat source is supplied from outside the system by a device not shown,
Once the steady state is reached, the drive machine Z and motor n are operated continuously.

In this embodiment as well, as in the embodiment shown in FIGS. 1 and 2, a relative velocity is generated between the liquid in the evaporator 12 and the liquid in the evaporator 12 by 10 rotations of the screw-shaped heat exchanger, and the spiral surface Dynamic pressure is generated in the liquid due to the slope, which cleans the outer surface of the spiral member 2, which is a heat transfer surface, and improves heat transfer by stirring the liquid inside the can. In addition, the pumping action generated by the rotation of the screw-type heat exchanger 1 generates a circulating flow within the evaporator 12, and the rotation of the rotor 17 promotes flow and mixing throughout the device, improving heat transfer and increasing heat transfer. It is possible to aspirate and send out liquids with high concentration and high viscosity, and it is possible to evaporate and concentrate liquids with high concentration and high viscosity.

Furthermore, in this embodiment, as in the embodiments shown in FIGS. 1 and 2, by rotating the heat exchanger 1 partially below the liquid level of the heated liquid, the heated liquid is heated. is formed into a thin film on the outer surface of the spiral member 2 above the liquid level, and also on the outer surface of the annular heat exchanger 13 due to the transport of the heated liquid by the rotating body 17, and thin film evaporation is performed, thereby improving heat transfer performance. will improve.

The spiral heat exchanger of each of the above embodiments has its screw shaft arranged horizontally, but the screw shaft is tilted so that a part of the heat exchanger is below the surface of the liquid to be heated. As the exchanger rotates, the liquid to be heated may be formed into a thin film on a heat transfer surface above the liquid level of a screw-shaped spiral heat exchanger, thereby performing thin film evaporation.

In addition, the annular heat exchanger in each of the above embodiments has an annular structure that surrounds the entire outer periphery of the spiral heat exchanger and is continuous in the circumferential direction. A plurality of tubes may be arranged in a ring around the outside of the spiral heat exchanger to form an annular heat exchanger.

Furthermore, although each of the above embodiments uses a single evaporator, the present invention can also be applied to a multi-effect evaporator or other type of evaporator.

〔Effect of the invention〕

The present invention can have the following effects.

(1) The annular heat exchanger installed outside the spiral heat exchanger can increase the bombing effect caused by the rotation of the screw-shaped spiral heat exchanger.

(2) Due to the rotation of the rotating body, the entire evaporator, especially 1
Improves the fluidity of the heated liquid in the gap between the evaporator and the annular heat exchanger, promotes the circulating flow of high-concentration and high-viscosity fluids, and enables the evaporation and concentration of high-concentration and high-viscosity fluids. Become.

(3) The rotation of the rotating body transports the liquid to be heated over the entire heat transfer surface of the annular heat exchanger, improving heat transfer.

[Brief explanation of the drawing]

Fig. 1 is a front view of an embodiment of the present invention partially shown in cross section, Fig. 2 is a perspective view of a spiral heat exchanger used in the above embodiment, and Fig. 3 is a perspective view of another embodiment of the present invention. FIG. 4 is a front view of still another embodiment of the present invention, partially shown in cross section; FIG. 5 is an explanatory diagram of the conventional evaporation method using a multi-effect can; FIG. 6 FIG. 7 is an explanatory diagram of an evaporation system using a conventional single-can vapor reflux system, and FIG. 7 is an explanatory diagram of an evaporation system in which a conventional evaporator has a built-in heat exchanger. 1... Spiral heat exchanger 2... Spiral member 3... Passage 4...
Shaft 5... One end of the shaft 6... Heat medium inlet hole 7... Other end of the shaft 8... Heat medium outlet hole 9... Partition plate 10... Thermal body inflow chamber 1
1... Heat medium outlet chamber 12... Evaporator 1
3... Annular heat exchanger 14... Heat medium heat exchange chamber
I5... Heat medium inlet hole 16... Heat medium outlet hole
17...Rotating body 18...Steam outlet 19.
...Pulley I...Belt 21...Pulley n...Motor n...Heat medium outlet hole...
・Standard solution tank 6...Standard solution delivery pump...
Piping r... Gas-liquid separator channel... Drive machine 4... Compressor (9)... Piping
31... Pipe 32... Condensate discharge pipe 33
... Condensate discharge pipe A... Concentrate delivery pump 35...
・Concentrate tank 36...Piping

Claims (1)

[Claims] A screw-shaped spiral heat exchanger with the inside of the evaporator forming a heat medium passage and installed in the evaporator in a horizontal or inclined state, with a part of the heat exchanger being below the surface of the liquid to be heated in the evaporator. , a drive device for rotating the spiral heat exchanger around the screw shaft; an annular heat exchanger provided outside the outer periphery of the spiral heat exchanger surrounding the heat exchanger; An evaporator comprising: an annular heat exchanger; and a rotating body arranged in a space between the inner wall of the evaporator, extending in the axial direction of the screw shaft, and fixed to the screw shaft.