JPH045912B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for discharging water vapor generated in a high vacuum (hereinafter simply referred to as vacuum evacuation) and an apparatus used therefor, and in particular, to The present invention relates to a technique for discharging and removing evaporated water vapor from a vacuum generator connected to a cooling can in order to obtain a high vacuum when cooling by flash evaporation within the can.

BACKGROUND OF THE INVENTION In order to cool water or an aqueous solution, it is conducted into a cooling can for flash evaporation under a high vacuum, and for this purpose a vacuum generator is connected to the cooling can. Therefore, water vapor is generated in the cooling can, and this water vapor must be discharged and removed from the vacuum generator. Conventionally, when it comes to exhausting water vapor, a condenser is installed in the connecting pipe between the cooling can and the vacuum generator, and a refrigerant is supplied to the condenser to indirectly cool the water vapor below the dew point, causing it to condense and become water. Alternatively, a steam booster is installed in this area, the water vapor is sucked and pressurized, and the water vapor is led to a condenser where it is directly or indirectly condensed and removed using normal cooling water. was taken. That is, these are the basics of vacuum water chillers or vacuum cooling devices, and are generally employed in various fields.

Problems to be Solved by the Invention However, in a condenser-type chilled water system, when the vacuum is high, the refrigerant, which has a temperature below the dew point of water vapor under the vacuum, has a temperature below the freezing point of the condensed water. In such cases, when the generated water vapor is guided to a surface condenser and cooled and condensed, the condensed water adheres to the surface of the heat transfer tube and freezes, making it impossible to continue the steam cooling and condensation operation.

On the other hand, in the case of a steam booster type chilled water system, when the entire amount of water vapor is sucked in by the booster, the pressure is increased from a high vacuum to a pressure that can be condensed with normal cooling water. There is a problem in that not only a large amount of water is required, but also a large amount of cooling water is needed to condense the steam on the booster outlet side, resulting in high operating costs.

Means for Solving the Problems Therefore, in the present invention, in order to solve the above problems, consideration has been given to the evacuation of water vapor under high vacuum.
The objective is to arrive at an economical method for removing water vapor, thereby providing a new chilled water cooling device.

That is, in the present invention, water vapor is discharged and removed by absorption, and water vapor generated under a high vacuum is absorbed by an absorber installed in the same vacuum system that connects the cooling can and the vacuum generator. The main idea is to introduce the absorbent into the absorber and bring it into direct gas-liquid contact with an absorbent such as carbonated soda or concentrated sulfuric acid for absorption and removal.
At the point where dilution heat is generated, a circulation pipe is installed between the upper and lower parts of the absorber, and a part of the pipe removes the dilution heat and cools the circulating absorption liquid by keeping its temperature below the boiling point at the operating pressure. This cold water cooling device is characterized by continuously absorbing and removing water vapor from the can to reduce the load on the vacuum generator.

Embodiments The present invention will be explained below with reference to embodiments shown in the drawings.

Reference numeral 10 denotes a cooling can whose interior is kept in vacuum. Water to be cooled supplied from upstream 11 is dispersed in the vacuum of cooling can 10 to perform flash evaporation, and saturated steam is sent from outlet 12 to the absorber. 20 and adiabatically cooled cold water is obtained from the recovery port 13.

The absorber 20 is a type of condenser known as a shelf-type condenser, and the saturated steam is supplied from an inlet 21 to the absorber 20 . 22 is a lower drain port,
A pipe 24 is connected from there to the liquid supply port 23 at the upper part of the absorber 20, forming a circulation line via an intermediate circulation pump 25. 26 is a distribution pipe for circulating liquid, and 27 is a non-condensable gas outlet at the top of the absorber 20.

Next, numeral 30 is an inlet for injecting a stock solution of an absorbent such as highly concentrated sulfuric acid or loaded soda, which is provided upstream of the circulation pump 25, and the stock solution in the storage tank T is injected by an attached pump. Reference numeral 31 denotes a discharge pipe drawn from the lower drain port 22 of the absorber 20, through which a portion of the absorbent diluted by water vapor is discharged via the metering pump 32.

40 is a heat exchanger provided downstream of the pump 25 in the circulation pipe 24, and supplies general cooling water 41 to cool the circulating fluid.

A condenser having a circulation system and a heat exchanger as described above is known, and in the present invention, in combination with a vacuum water chiller, it is used as an absorption device for cooling water vapor in a vacuum. It is designed to be connected to a can.

Next, what is generally designated by 50 is a vacuum generator, and in this embodiment, a steam ejector, a condenser, and a vacuum pump are illustrated. That is, the ejector 51 is not directly connected to the cooling can 10, but its suction port 52 is connected to the top 27 of the absorber 20.
It is connected to the outlet 12 of the cooling can 10 via the absorber 20, forming a vacuum conduit that maintains the vacuum in the cooling can 10 by suction from the ejector 51. On the other hand, as is well known, the steam discharged from the ejector 51 is sent to the condenser 53, and the cooling water 51 is sent to the condenser 53.
4 is supplied and condensed, and the non-condensable gas contained therein is discharged.

In this embodiment, a plate type condenser was used as the absorber, but other types of gas-liquid contact devices such as a packed column and a plated column can also be used.

Effects The effects of the exhaust method and device of the present invention will be described by explaining the operation of the chilled water cooling device shown in the above configuration.

Steam outlet 12 of cooling can 10 and vacuum generator 5
A pipe line for maintaining a vacuum is connected to the suction port 52 of No. Water vapor generated in the cooling can 10 under high vacuum is led to the absorber 20, where it is brought into gas-liquid contact using an aqueous solution with a low partial pressure of water vapor, such as carbonated soda or sulfuric acid, as an absorbent under vacuum in the container. Water is absorbed by it. The absorbent is circulated according to the above-mentioned structure, and is diluted by absorbing water vapor. The liquid temperature of the diluted absorbent increases due to the heat of dilution, and is cooled in the heat exchanger 40.

On the other hand, the absorbent stock solution is injected from the injection port 30 to replenish the diluted solution and generates dilution heat in the circulating diluted solution, but since the injection point is upstream of the heat exchanger 40, this dilution heat is also generated. removed from exchanger 40;
The circulating fluid is extracted from the discharge pipe 31 in proportion to the amount of water supplied and the amount of stock solution added. The circulating fluid whose inlet temperature of the absorber 20 is determined by the heat transfer area of the heat exchanger 40 and the conditions of the cooling water 41 is controlled in flow rate by the circulation pump 25 to adjust the amount of circulating fluid at the outlet of the absorber 20 to that level. It is kept constant below the boiling point under vacuum to ensure absorption of water vapor.

Here, if loading soda is used as an absorbent and the concentration of the absorbent stock solution is set to 50%, the heat exchanger 40
When the temperature of the cooling water 41 is set to 32°C, by setting the vacuum of the vacuum generator to 12 Torr or less and adjusting the amount of circulating fluid of the absorbent, the temperature of the circulating fluid at the absorber outlet is set to 43°C, and the vacuum is reduced to 43°C. By maintaining the boiling point of the diluted absorbent at 48° C. or lower, the steam generated from the cooling can 10 can be continuously absorbed and removed, and the load on the vacuum generator in the vacuum pipe can be reduced.

Effects of the Invention The present invention provides an absorber that circulates an absorbent in a vacuum system that connects a cooling can and a vacuum generator, and processes the absorbed dilution heat of the circulating absorbent and makes it possible to control the water vapor absorption conditions. Therefore, it is possible to remove water vapor under stable setting conditions, and this makes it possible to significantly reduce the load on the vacuum generator in a chilled water cooling system that combines a cooling can and a vacuum generator, for example, compared to the conventional steam booster type. The utility costs can be reduced to about 1/2 compared to other water chillers. In addition, other solutions with a high boiling point can be used in place of sulfuric acid and sodium chloride, and can be selected from glycerin, ethylene glycol, calcium chloride, etc. Furthermore, in the case of sterile soda sulfuric acid, etc., it can be used as a part of the diluted product used in other equipment, and there is no need to consider its consumption.

Note that the present invention is not limited to cold water cooling devices, but can be applied to absorption and removal of water vapor at the top of a distillation column in a steam stripping operation.
It is possible to replace the first stage cooling tank with a distillation column.

In summary, the present invention provides an exhaust method in which water vapor is removed by absorption by an absorbent, and a chilled water cooling system in which an absorber is interposed between the combination of a cooling can and a vacuum generator. Therefore, it can be concluded that this method is effective in reducing utility costs compared to conventional methods and devices.

[Brief explanation of drawings]

The drawing shows an embodiment of the invention in the form of a flow sheet. 10...Cooling can, 12...Steam outlet, 13...
...Cold water recovery port, 20...Absorber, 21...Inlet, 22...Drain port, 23...Liquid supply port, 24...
Circulation pipe line, 25... Circulation pump, 27... Vacuum system outlet, 30... Stock solution inlet, 31... Diluted liquid discharge pipe, 40... Heat exchanger, 50... Vacuum generator,... Vacuum conduit.

Claims (1)

[Claims] 1. A method for removing water vapor in a vacuum system,
An absorber is provided in the vacuum system, water vapor is introduced into the absorber, and the absorbent that mixes and dissolves with the water vapor is circulated in the absorber to bring it into direct gas-liquid contact. A vacuum evacuation method characterized by removing dilution heat and adjusting the circulating amount of absorbent to maintain the temperature of the circulating absorbent below the boiling point at the operating pressure. 2. The evacuation method according to claim 1, wherein the absorbent is one of carbon soda, sulfuric acid, or an absorbent with a high boiling point rise. 3. In a vacuum chilled water cooling system consisting of a cooling can which cools water or an aqueous solution by flash evaporation under vacuum and a vacuum generating device which forms and maintains a vacuum by absorbing the inside of the cooling can, the cooling can and the vacuum generating device are are connected via an absorber having a circulation pipe, and the circulation pipe is provided with an inlet for the absorbent concentrate and a discharge pipe for the circulating liquid diluted by water vapor, as well as a circulation pump and a heat exchanger. A vacuum chilled water cooling device comprising: 4. The vacuum chilled water cooling device according to claim 3, wherein the absorbent stock solution inlet is provided upstream of the heat exchanger in the circulation pipe.