JPH0613081B2 - High vacuum evaporator - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to various devices for concentration, crystallization, etc. that generate steam under high vacuum, and in particular, a heat pump that uses the amount of heat of self-steam as a heat source of the device. It is about.

2. Description of the Related Art In a high-vacuum, low-temperature evaporator, water vapor generated from the evaporator must be discharged and removed. Conventionally, regarding the exhaust of this steam, a condenser is provided in the connecting pipe between the evaporator and the vacuum generator, and a refrigerant is supplied to this condenser to indirectly cool the steam below the dew point, condense it and remove it as water. Or the refrigerant CFC (R-1
A compression heat pump low temperature evaporator using 1) has been developed.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, in the condenser type evaporator, a chiller unit is required to obtain a low-temperature refrigerant, and the required power is large and a large amount of cooling water is required. There was a point. Further, in a compression heat pump low temperature evaporator using a refrigerant (R-11), when the refrigerant temperature is 24 ° C or lower, the vapor pressure of the refrigerant becomes atmospheric pressure or lower, and the minimum temperature as an evaporator is ~ 27 ° C (saturated). Water vapor pressure ~ 26.5 Tor
However, there is a problem that the running cost becomes high because the power consumption of the compressor becomes large and the running cost becomes high.

Means for Solving the Problems In order to solve the above problems in the present invention, the above-mentioned evaporation device was examined, and an economical heat pump system under high vacuum was reached. It is intended to provide an absorption heat pump type evaporator.

That is, in the present invention, the water vapor generated under high vacuum is introduced into an absorber provided in the same vacuum system connecting the evaporator and the vacuum generator, and the absorber of caustic soda or concentrated sulfuric acid is directly introduced in the absorber. In an evaporator with an absorption heat pump, which uses gas-liquid contact for absorption and removal, and at the same time uses the diluted and heated absorption liquid as a self-heat source for the evaporator, circulation between the upper and lower parts of the absorber By installing a pipe and installing a heat exchanger between the absorber outlet and the heating can to remove only excess heat, heat is continuously recovered under high vacuum and the temperature of the circulating absorbent is controlled. It is a high-vacuum evaporator which keeps the boiling point or less at a pressure and continuously absorbs and removes water vapor from the evaporator to reduce the load on the vacuum generator.

As described above, the high vacuum low-temperature evaporator uses the high boiling point rise of sulfuric acid and caustic soda, consumes less cooling water, and does not require compression power.

Embodiments The present invention will be described in detail below with reference to the flow charts of embodiments shown in the drawings.

In the figure, 10 is an evaporator, which has an evaporation can 11 and a heating can 12, and a circulation pipe having a circulation pump 13 is formed between the evaporation can 11 and the heating can 12 to form a target processing liquid A.
Is vaporized to generate water vapor. The heating can 12 is formed as a heat exchanger, guides heated steam to the upper inlet 14, and takes it out from the lower outlet 15. P is the extracted liquid after the treatment.

Next, 20 is an absorber which is a heat source of the above-mentioned heating liquid, and the lower part 21 of the absorber is evaporated water vapor V ₁ from the top 16 of the evaporator 11.
And a circulation line C for absorbing liquid is formed between the bottom part 22 and the top part 23, and this line has a circulation pump 24 and a heat exchanger 25. The absorption liquid which is connected to the inlet 14 and the outlet 15 of 12 and which is supplied with the high-concentration absorbent from the absorbent tank 30 via the pump 31, is diluted with the absorbed water vapor V ₁ and circulates in the pipeline C is the pump 32. It is appropriately taken out as the diluting liquid 33 via.

Reference numeral 26 is a sprinkler tube provided on the upper portion of the absorber 20, and 27 is a top discharge port for the non-condensable gas in the absorber 20.

Next, 40 is a vacuum generator, 41 is a booster, 4
2 is a condenser, 43 is cooling water, and 44 is condensate. P.
Is a vacuum pump. The vacuum generator 40 is the absorber 2
It is connected to the top portion 27 of No. 0 by a pipe line V _{2, and} is also connected to the evaporator 11 through the inside of the absorber 20 to form a vacuum system of the evaporator 10 and achieve a high vacuum.

Action The liquid A to be treated introduced to the evaporator 10 is heated by heat exchange in the heating can 12, and is evaporated under vacuum while being circulated between the circulation pump 13 and the evaporation can 11, so that the water vapor V ₁ is absorbed in the absorber. When the evaporation device is sucked by 20, and the evaporator is a concentrating device, the treatment liquid is concentrated and taken out as a recovery liquid P by repeating the circulation.

On the other hand, in the absorber 20, the absorbent is circulated by the circulation pump 24, enters the absorber 20 from the spray pipe 26 under the high vacuum determined by the operating conditions, and the water vapor V generated in the evaporator 10 is generated there. Absorbs ₁ . This will dilute the absorbing liquid. The diluent 33 is appropriately extracted. Sulfuric acid and caustic soda, which have a high boiling point, are selected as this absorbent, and the absorption liquid is heated by the heat of dilution and condensation heat of water vapor absorption and is sent to the heating side of the heating can 12 to evaporate the target liquid. It becomes a heat source. That is, the evaporator 10 forms an absorption heat pump that supplies the heat of its own vapor to the heating can 12 as a heat source.

In addition, as the function of the absorber 20, the high temperature absorbent is added to the diluted and heated absorption liquid to further raise the temperature, and then the surplus heat is removed by the heat exchanger 25. Since the heat is removed by the low temperature liquid to be treated at 12, the absorbing liquid is maintained at a low temperature, and the partial pressure of water vapor in the absorbing liquid becomes small, so that the concentration of the circulating absorbing liquid can be lowered. That is, the required amount of the high concentration absorbent injected from the pump 31 is small.

Here, in the evaporator having the above-mentioned configuration, when the temperature of the liquid to be treated in the evaporator is set to 15 ° C., the internal pressure of the absorber by the vacuum generator is set to 9 Torr, and the amount of circulating water of the absorbed liquid is 200 Kg / hr. 41 tons / hr, 48 absorbents
When 1400 kg / hr of caustic soda of wt / o is replenished, the absorption liquid heated to 37 ° C. due to the generation of dilution heat passes through the heat exchanger 25 with cooling water of 32 ° C. and then the absorption liquid becomes 3
The liquid to be treated in the heating can 12 is heated and evaporated at 5 ° C.
At 1.5 ° C., it enters the absorber 20 from above as 42.2 wt / o caustic soda. At this time, the diluting liquid is withdrawn as 42 wt / o for 1600 kg / hr and other uses.

EFFECTS OF THE INVENTION The present invention provides an absorber for circulating an absorbent in a vacuum system that connects an evaporator and a vacuum generator, and absorbs water vapor of the evaporator by the absorbent and circulates the absorbing liquid for heating the evaporator. In the evaporation device to be, by providing a heat exchanger between the absorber outlet and the heating can to remove only excess heat, thereby forming an absorption heat pump that operates continuously under high vacuum, The consumption of heat energy of the evaporator used under high vacuum can be made economical, and at the same time, the load on the vacuum generator can be reduced.

In addition, since sulfuric acid and caustic soda used as absorbents for absorbers are used by diluting separately, consider the consumption of materials to achieve the removal and removal of water vapor for the purpose of concentrating the evaporator, crystallization, etc. No need. Therefore, when this is compared with, for example, a conventional chiller type high vacuum evaporator, the utility cost can be reduced to about 1/3.

[Brief description of drawings]

The drawings show a flow chart of an embodiment of the evaporator of the present invention. 10 ... Evaporating device, 11 ... Evaporating can 12 ... Heating can, 13 ... Circulating pump A ... Liquid to be treated, P ... Extracted liquid 20 ... Absorber, 24 ... Circulating pump 25 ... Heat exchange vessel, 26 ...... Chiekikan 30 ...... absorber vessel, C ...... circulation line 40 ...... vacuum generator, 41 ...... booster V _{1, V 2} ...... vacuum system line, W ...... cooling water

Claims (2)

[Claims] 1. An evaporator, a vacuum generator connected to the evaporator, and an absorber provided in a vacuum system between the evaporator, the absorber having a circulation line for absorbent, This circulation line forms a heat exchanger in the circulation line and the heating can of the liquid to be treated which circulates between the evaporation can and the heating can of the evaporator.
In an evaporator adapted to use the absorbing liquid as a self-heat source, a diluting liquid extracting pipe and a high-concentration absorbent supplying port are provided between the absorber outlet of the absorbent circulating pipe and the heating can,
A high vacuum evaporator comprising a heat exchanger for cooling excess heat between the supply port and the heating can. 2. The high vacuum evaporator according to claim 1, wherein the absorbent is sulfuric acid or caustic soda.