JPS624402A - High vacuum evaporator and absorber used therefor - Google Patents

Abstract

PURPOSE:To improve heat recovering efficiency of a high vacuum evaporator by providing an absorber comprising an evaporator, vacuum generating device and a heat exchanger comprising a shell and many tubes and, gy connecting the shell to the evaporating kettle and the tube side to a heating kettle. CONSTITUTION:Liquid A to be treated and fed to an evaporator 10 is heat- exchanged in a heating kettle 12, and generated steam V1 is sucked by an absorber 20 and absorbed by a liquid absorbent. Thus, the liquid absorbent flowing down through the tubes 22 is diluted and the tubes 22 are heated. On one hand, water C1 circulated through the absorber 20 is heated in the tubes 22, and steam V2 is transported from an exhausting port 26 to the heating kettle 12 of the evaporator 10, serving as heat source for evaporation of the liquid A to be treated. Noncondensible gas evaporated from the absorbent is sucked by the vacuum generating device 40 and discharged.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to an evaporation device for concentration, crystallization, etc. that generates water vapor under high vacuum, and in particular uses the calorific value of self-steam as a heat source for the device. The present invention relates to an evaporator and an absorber used in the evaporator.

BACKGROUND ART In an evaporation device that generates water vapor under vacuum and performs concentration, crystallization, etc., the generated water vapor must be discharged and removed in order to function as a vacuum generator.

Conventionally, this method of exhausting water vapor involves: (1) A condenser with a refrigerator is installed in the connecting pipe between the evaporator and the vacuum generator, and a refrigerant is used to indirectly cool the water vapor below the dew point and condense it. A method in which water is removed as water, and a method in which it is replaced with vapor as a medium, the pressure and temperature are raised by a compressor, and the water vapor is used as a heat source for the evaporator, and the water vapor is discharged as a drain.

etc. were taken.

Regarding the absorber, (1) A method in which a heat transfer tube is provided inside the absorber and hot water is supplied to the heat transfer tube, and the heated water is extracted by the dilution heat of the absorbent in the absorber. (2) By providing a heat transfer tube inside the absorber and supplying hot water to the heat transfer tube, the hot water whose temperature has been raised by the heat of dilution of the absorbent in the absorber is introduced into the flash can and flash evaporated. It was known that heat could be recovered by methods such as extracting heat as steam.

Regarding the conventional technology mentioned above, first of all, regarding high vacuum evaporation equipment, (1) Condenser type evaporation equipment requires a refrigerator, requires a large amount of power, and requires a large amount of cooling water. do.

(2) A compression heat pump-type low-temperature evaporator requires a compressor with a large power requirement, is noisy, requires a dedicated person to operate it, and must remove excess heat. In addition, the handling of high pressure gas is subject to legal regulations.

In addition, in order to recover heat by an absorber, (1) To extract K as hot water, the overall heat transfer coefficient U value of the heat exchanger is small, so the heat transfer area of the heating can and the heat exchanger in the absorber is large. On the other hand, it is necessary to have a large temperature difference in heat exchange.
Heat recovery temperature becomes lower.

(2) If hot water is extracted and then replaced with steam using a flash can, a separate flash can must be installed and the amount of circulation must be increased.

There were various problems, both advantages and disadvantages, and a comprehensive solution was desired.

Means for Solving the Problems In the present invention, water vapor from the evaporator is absorbed at high temperatures by using sulfuric acid or caustic soda, which have a high boiling point, as the absorbent used in the absorber. Therefore, (1) high-temperature heat can be recovered from the heat of low-temperature steam, making it unnecessary to install a compressor. In addition, (2) the absorbent in the absorber is supplied once-through, and is taken out as a diluted liquid and used for other purposes, so when forming an absorption heat pump cycle, it is possible to In addition, it does not require concentration or circulation of the diluted solution, and does not require energy for concentration. Furthermore, (3) the structure of the absorber is such that water circulation forms a heat exchanger between the shell and the inside of the tube to directly generate steam and recover heat, while the condensation heat of the absorption liquid is absorbed by the absorption of the removed steam. The heat of dilution is exchanged between the inner and outer surfaces of the tube wall, thereby avoiding the above-mentioned problems of heat recovery in conventional absorbers.

By improving the above three points, we have completed a high vacuum evaporator with high overall efficiency. Embodiments The present invention will be described in detail below with reference to flowcharts of embodiments shown in the drawings.

In the figure, reference numeral 10 denotes an evaporator, which has an evaporator 11 and a heating can 12. A circulation pipe having a circulation pump 13 is formed between the evaporator 11 and the heating can 12, and the target ronin is It evaporates and produces water vapor. The heating can 12 is formed as a heat exchanger and leads heating steam to the upper part 14,
The processing liquid obtained by draining and evaporating from the lower outlet 15 is recovered as a concentrated liquid P etc. from the lower liquid chamber 16. 17 is a separator, from the top 18 of which water vapor V
, is taken out and sent to the absorber 20. S is starting steam.

The absorber 20 is the main part of the present invention, and is configured to have dual functions as an absorber and an evaporator. First, the evaporator is an in-tube liquid film falling type heat exchanger consisting of a shell 21 and a large number of tubes 22, 22. That is,
A circulation pipe C□ having a water circulation pump 25 is formed between the lower liquid chamber 23 and the upper part 240, and the exhaust port 26 at the upper part of the liquid chamber 23 is connected to the upper part 14 of the heating can 12 through a pipe V. , and the steam pipe line V□ from the top 18 of the separator 1T is connected to the air supply port 2B at the bottom of the shell 21, functioning as an evaporator for circulating water using the evaporated steam V as a heat source. The liquid chamber 23 is connected to a connecting pipe 19 for the drain 15 from the heating can 12 and the drain from the separator 27 to form a closed water cycle.

Next, we will discuss the structure of the absorber. The absorption chamber 30 is formed in the middle part of the upper and lower tube plates 29.29 of the tube 22, has a pipe C3 connected between the lower liquid drain port 31 and the upper liquid supply port 32, and has a circulation pump 33. The absorbent solution injected from the stock solution tank of the absorbent S through the pump is circulated, and the diluted solution is taken out one after another. 34 is a tank for storing liquid. 3
Reference numeral 5 denotes a partition plate provided at the upper part of the absorption chamber 30, which forms a liquid layer 36 of absorption liquid between the height of the liquid supply port 32 and a small area around the tubes 22 and 22 passing through the partition plate 37. Gap 37
．． By dripping the absorbent from 3T, an extratubular liquid film falling type heat exchanger is formed, and at the same time, a wet wall type absorber is formed.

With the above structure, the absorber 20 is characterized in that a heat exchanger is formed within the shell 21 on both the inner wall surface and the outer wall surface of the tube 22.

Next, 40 is a vacuum generator, 41 is a booster,
42 is a condenser, 43 is cooling water, 44 is condensate, vp
is a vacuum pump. The vacuum generator 40 is connected to the upper exhaust port 45 of the absorber evaporator 20 by a pipe v8, and the absorber 20. The evaporator 11Vc is also communicated through the pipe v1, forming a vacuum system of the evaporator 10 and achieving high vacuum.

Operation The operation of the present invention will be described by describing the operation of a preferred embodiment.

The liquid A to be treated that is led to the evaporator 10 is heated by heat exchange in the heating can 12, and is evaporated under vacuum while being circulated between the evaporator 11 and the evaporator 11 by the circulation pump 13. If the evaporator is a concentrator, the treated liquid is concentrated and taken out as a recovered liquid P.

In the following, the symbols of the conduits shown in the structure of the apparatus also refer to the fluids passing through them.

Water vapor Tut is drawn into the shell of the absorber 20 from the air supply port 2B and absorbed by the absorbent circulating in the absorption chamber 30 portion. This absorption dilutes the absorbent liquid flowing down the outer surface of the tube 22, generates condensation heat and dilution heat, and heats the tube 22 from the outer surface, and the absorbent becomes a diluted liquid and flows into the tank 34 of the lower liquid reservoir. Reservoir, conduit C.

The liquid is circulated, extracted as a diluted liquid, and sent to other processes in a once-through manner.

As the absorbent S, sulfuric acid or caustic soda, which has a high boiling point rise, is selected, and its circulation system inside and outside the tube 22 is completely independent from the circulation system of water as an evaporator.

On the other hand, the absorber 20 evaporates the circulating water C1 at the boiling point temperature. That is, the absorption liquid C! in the shell 21! absorbs the water vapor v1, heats the tube 22 from the outside with condensation heat and dilution heat, heats the circulating water C1 flowing down on the inner surface of the tube wall, evaporates the water, and takes out the water vapor V from the exhaust port 26. and sent to the evaporator 10.

This water vapor V is sent to the heating side of the heating can 12 of the evaporator 10, and is sent to the evaporator! Serves as a heat source for evaporation of 1G ronin. That is, the evaporator 10 is configured to supply the heating can 12 with heat from its own storage air as a heat source.

Incidentally, the evaporated vapor contained in the liquid to be treated and the non-condensable gas evaporated from the absorbent are drawn to the vacuum generator 40 through the pipe v1 and discharged. The temperature of the liquid inlet was 15℃, and the internal pressure of the evaporator was 10T.
When evaporation is performed at a rate of 100 Kg/hr, the internal pressure of the absorption chamber 30 is 9.8 Torr, and the absorption liquid is absorbed by the once-through supplied absorption liquid. That is, the absorbent was 98 wt% concentrated sulfuric acid, supplied at 184 Ky/hr from stock solution tank +4, and at 20) Ky/hr at 38°C.
It is diluted to 63.8 wt% by absorbent with a circulating flow rate of hr. This absorption liquid gradually absorbs steam v1, is diluted by 63.5wt1ljlC in the lower part, and heats and evaporates the water in the tube with the heat of condensation and dilution, and at the same time, the absorption liquid itself is cooled by the evaporation of the water in the tube. When the temperature reached 37°C, the total amount of 284/hr that entered the system from outside was taken out as diluted sulfuric acid, and the remainder was recycled.

Meanwhile, during this period, the circulating water in the tube 22 of the absorber 20 is evaporated from a boiling point temperature of 34° C. in a low vacuum of 40 Torr, and is sent to the heating can 12 as steam V.

Effects of the Invention Since the present invention is constructed as described above, it achieves the first purpose of discharging and removing water vapor generated from an evaporator in a high vacuum, and also uses the thermal energy of the water vapor to heat the evaporator. The second objective of using an absorption heat pump with self-steam as the source was also achieved. According to the present invention, the entire device does not require accessory equipment such as a compressor or flash can, and does not require the power to operate them.In terms of thermal energy, high-temperature heat can be recovered from low-temperature heat and absorbed. By directly generating steam in the absorber, the U value becomes high, the temperature difference within the absorber can be kept small, and high-temperature heat can be recovered.

In addition, not only does it not require cooling water, but the absorbent is used once-through without regenerating and concentrating, so the heat recovery rate (coefficient of performance) is twice that of conventional Type 2 heat pumps. It becomes.

Furthermore, since the heat of the diluted and heated absorption liquid is replaced with water vapor, it is highly safe and can be applied to evaporation equipment for foods, pharmaceuticals, etc., and on the other hand, the heat exchange efficiency in the heating can is high, allowing heat transfer. Good secondary effects have been obtained even though the area is small.

[Brief explanation of the drawing]

The drawing shows an embodiment of the evaporator according to the invention in a flow diagram. 10...Evaporator 11...Evaporator 12...Heating can 13...
・Circulation pump 1T・・・Separator 19・
...Water pipe A...Liquid to be treated
P...Recovered liquid 20...Absorber 21...
...Shell 22 ...Tube 25
...Circulation pump 26...Exhaust port
2B... Air supply port 2T... Separator C1... Circulation pipe C2... Circulation pipe S... Stock solution D... ···Diluted solution

Claims (3)

[Claims] (1) Consisting of an evaporator, a vacuum generator connected to the evaporator, and an absorber installed in the vacuum system connecting these, the absorber has a shell and a number of tubes, and is a heat exchanger. It has an absorbent circulation line with an absorbent inlet and a diluted liquid outlet, and a closed cycle water circulation line, and the inside of the shell is connected to the evaporator of the evaporator. A high vacuum evaporation device characterized in that the tube side is connected to a heating can and uses the steam generated in the absorber as a self-heat source. (2) The evaporator according to claim 1, wherein the absorbent is highly concentrated sulfuric acid or caustic soda. (3) An absorber that has a shell and a number of tubes to form a heat exchanger, and the absorber has a water circulation pipe between the lower part and the upper part to reduce the amount of liquid film flowing through the pipe. An absorbent circulation pipe that forms a heat exchanger and forms an absorption chamber in the shell between the upper and lower parts of the tube, and has an absorbent inlet and a diluent outlet between the lower and upper parts. The absorbent is made to flow down the outer surface of the tube inside the absorber, and the shell is provided with a steam supply/exhaust port, and the absorption of the supplied steam causes the absorbent to generate condensation heat and dilution heat to circulate the inside of the tube. An absorber characterized by forming an extratubular liquid film falling type heat exchanger for water.