JPS6388001A - Liquid concentrator - Google Patents

Abstract

PURPOSE:To prevent the generation of the cavitation of the pump of a liquid recirculation line by preventing the generation of air bubbles in an evaporator, by providing a liquid barrier member at the position opposed to the upper opening of a heat transfer pipe above the liquid level of the liquid sump part in the evaporator. CONSTITUTION:An evaporator 2 is integrally formed to the upper part of a heater 1, and a partition plate 28 is provided between both of them to form a liquid sump part 27 thereon, and a liquid barrier plate 29 is provided above the liquid level of said liquid sump part 27. The liquid barrier member 29 is formed into a conical shape having an obtuse vertical angle. The liquid supplied to the lower water chamber of the heater from a waste liquid recirculation tank 12 is upwardly injected from the upper outlet of a heat transfer pipe 4 while rising through said pipe 4. The liquid injected rises through the liquid in the liquid sump part 27 to collide with the liquid barrier member 29 as a two-phase stream. At this time, the liquid is subjected to gas-liquid separation by the inertial force of collision and the change in a flow direction.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a liquid concentrator for concentrating and reducing the volume of various liquid wastes such as radioactive waste liquids, particularly waste liquids containing sodium sulfate, nitric acid solutions, and impurities.

[Prior art]

A conventional liquid concentrator will be explained based on FIG. The heater 1 and the evaporator 2 are communicated with each other by a communication line 3, and the liquid to be treated heated in the heater 1 is sent through the communication line 3 into the evaporator 2, where it is heated. Gas and liquid are separated. The heater 1 has one or more heat transfer tubes 4 extending vertically inside the heater 1, and when the liquid flows upward inside the heat transfer tubes 4, it absorbs heat from surrounding heated steam and is heated. It's starting to leak more.

Reference numeral 5 indicates an inflow line for heating steam, and the inflow line 5 is equipped with a heating steam control valve 6. 7 indicates a condensate discharge line, and the condensate condensed by the heat transfer tube 4 is discharged to the outside of the heater 1 through the condensate discharge line 7. 8 and 9 are heaters 1
10.1 shows the upper and lower partition plates, respectively.
1 indicates the upper heater ice chamber and the lower heater ice chamber, respectively.
This heater 1 is equipped with a liquid supply system. The liquid supply system supplies waste liquid to be treated into the evaporator 1, and is composed of a waste liquid tank 12, a supply line 13, a supply pump 14, and a waste liquid supply amount control valve 15. 16 indicates a waste liquid flow meter.

The lower part of the evaporator 2 is formed into a tapered shape, and the bottom part is connected to the lower heater water chamber 11 of the heater 1 by a liquid circulation line 17.
is communicated with. A circulation pump 18 is provided in this liquid circulation line 17 to return the liquid in the evaporation chamber 2 to the heater 1. A cylindrical baffle 19 is provided in the center of the evaporator 2. The liquid supplied into the evaporator 2 from the heater 1 through the communication line 3 is tangentially injected onto the baffle 19, and is separated into gas and liquid by the centrifugal force, and the gas phase rises inside the evaporator 2. However, the liquid phase becomes a vortex and falls to the lower part of the evaporator 1, where it accumulates. Evaporator 2 is equipped with a vapor condensation system. This vapor condensation system condenses vapor into liquid and recovers it, and is formed from a demister 20 provided at the top of an evaporator 2 and a condenser 21 communicating with the demister 20.

22 indicates a cooling water line.

The evaporator 2 is provided with a liquid level control instrumentation 23, and an output signal from the liquid level control instrumentation 23 operates the heated steam control valve 6 and the waste liquid supply amount control valve 15.

Reference numeral 24 denotes a receiving tank for concentrated liquid, which is communicated with the liquid circulation line 17 via an on-off valve 25.

[Problem that the invention seeks to solve]

However, in the above-mentioned conventional liquid concentrator, the liquid phase part of the liquid injected into the evaporator 2 from the communication line 3 becomes a vortex after gas-liquid separation and accumulates in the lower part of the evaporation chamber 2, which tends to trap air bubbles 26. There was a problem in that the air bubbles 26 were sucked together with the liquid into the circulation pump 18, causing cavitation in the pump 18.

SUMMARY OF THE INVENTION An object of the present invention is to provide a liquid concentrating device that prevents the generation of bubbles in the liquid phase portion of an evaporator and prevents cavitation from occurring in a circulation pump provided in a liquid circulation line.

[Means for solving problems]

The present invention comprises a heater equipped with a liquid supply system, an evaporator installed in the upper part of the heater and equipped with a vapor condensation system, and an evaporator installed in the lower part of the evaporator that communicates with the inlet side of a liquid circulation line. a liquid reservoir extending vertically into the heater, an upper outlet opening upwardly into a lower part of the evaporator, and a lower inlet communicating with the outlet side of the liquid circulation line; A heat tube, a circulation pump provided in the liquid circulation line, and a liquid impingement member provided in the evaporation chamber at a position above the liquid level of the liquid reservoir and facing the upper opening of the heat transfer tube. It is prepared.

[Effect]

The present invention allows the liquid injected upward into the evaporator from the upper outlet of the heat transfer tube to impinge on an opposing liquid impacting member,
The impact scatters the gas and liquid, and the gas phase rises in the evaporator and is condensed in the vapor condensation system.The liquid phase falls into the liquid reservoir and collects, and the liquid in this liquid reservoir is circulated. The pump is driven to send the water back to the heater for circulation.

〔Example〕

An embodiment of the present invention will be described based on FIGS. 1 and 2. The lower part of the evaporator 2 is connected to the upper part of the heater 1, and the two are integrated. A liquid reservoir 27 is provided at the bottom of the evaporator 2, and a liquid circulation line 17 is connected to the bottom of the liquid reservoir 27.
The entrance side is connected. The upper outlet of the heat transfer tube 4 in the heater 1 is opened upward in the lower part of the evaporator 2. In this embodiment, the upper outlet of the heat transfer tube 4 is opened in the upper surface of a partition plate 28 that partitions the heater 1 and the evaporator 2. has been done. In this embodiment, a liquid impinging member 29 is provided at a position above the liquid level of the liquid reservoir 27 in the evaporation chamber 2 and facing the upper opening of the heat transfer tube 4. In this embodiment, the liquid impinging member 29 has an apex angle. It is formed into a conical shape with an obtuse angle. Since the other configuration is the same as that shown in FIG. 6, the liquid supplied to the lower heater water chamber 11 of the heater 1 through the same inlet 13 is heated to the boiling point temperature while rising inside the heat transfer tube 4. and is injected upward from the upper outlet. This injection force is generated by the pressure of the circulation pump. The injected liquid rises while boiling in the liquid in the liquid reservoir 27,
The two-phase flow impinges on the liquid impinging member 29 located above the liquid level. At this time, the liquid is separated into gas and liquid due to the force of collision, the four forces, and the change in flow direction based thereon, and the gas phase rises in the evaporator 2 and is condensed by the vapor condensation system.

On the other hand, the liquid phase falls into the liquid reservoir 27 and accumulates there. The accumulated liquid is returned to the lower heater water chamber 11 of the heater 1 by the circulation pump 18 and is circulated. The reduced amount due to this generation is supplied into the heater 1 from the liquid supply system. In this liquid concentration, the liquid phase that falls into the liquid reservoir 27 hits the liquid impacting member 29 and is scattered.
Unlike the conventional method, a vortex is not generated, and therefore, there are few air bubbles drawn into the liquid in the liquid reservoir 27. As a result, when the circulation pump protrusions 30 are provided at predetermined intervals from the center toward the outer periphery, the flow direction of the liquid injected from the heat transfer tube 4 is drastically changed by the protrusions 30, so that the liquid flows to the side surface inside the evaporator 2. The liquid phase can be prevented from scattering, improving the gas-liquid separation rate, and since the liquid phase is sufficiently dispersed and falls, the falling edge becomes smaller, and the risk of air bubbles being entrained in the liquid is further reduced. When the projections 30 are arranged around the center of the liquid impacting member 29 at predetermined intervals, the drop of the liquid phase is distributed almost uniformly with respect to the liquid surface due to its symmetrical structure.
The effect is further increased by reducing the number of falling blades.

As shown in FIG. 3, when the projection direction of the protrusion 30 is tilted outward, the flow resistance of the vapor for gas-liquid separation is reduced. Providing the protrusion 30 in this way improves the gas-liquid separation efficiency, thereby preventing the occurrence of a situation where the differential pressure of the demister 20 increases in a short time and the operation of the liquid concentrator is stopped due to the high differential pressure of the demister. .

In this embodiment, the lower part of the liquid reservoir part 27 is formed into a torus ring shape as shown in FIG. Since the liquid in the liquid reservoir 27 can be discharged uniformly, the liquid level can be kept almost constant. That is,
Local or sudden fluctuations in the liquid level due to the pump suction of the circulation pump 17 can be prevented, and from this point of view as well, the risk of bubble entrainment can be reduced. Incidentally, since sludge also accumulates in the liquid reservoir 27, it is desirable that the bottom be circular or conical in order to facilitate its discharge.

In this embodiment, if the communication portion 31 of the liquid reservoir 27 with the liquid circulation line 17 is provided at a lower position than the upper opening of the heat transfer tube 4, boiling, evaporation, and water sprinkling on the liquid surface of the liquid reservoir 27 will occur. It is possible to eliminate the influence of the turbulent flow of liquid caused by falling, and even air bubbles that are somewhat caught up immediately rise due to buoyancy and do not reach the communication portion 31.

In this embodiment, by setting the upper opening of the heat exchanger tube 4 below the liquid level of the liquid reservoir 27, water head pressure can always be applied within the heat exchanger tube 4, so that boiling and evaporation within the heat exchanger tube 4 can be prevented. can be prevented.

FIG. 4 is a sectional view of a main part showing another embodiment of the present invention. In this embodiment, a partition member 32 is provided between the heat exchanger tube 4 side of the liquid reservoir section 27 and the communication section 31 side of the liquid MA line 7, and a liquid flow hole 33 is bored in this partition member 32. 0 According to this embodiment, the partition member 32 blocks the turbulent flow of the liquid in the liquid reservoir 27 due to liquid injection from the upper opening of the heat transfer tube 4 and subsequent boiling and evaporation, and the liquid on the circulation line 17 side is blocked by the partition member 32. It is possible to avoid disturbing the This can prevent hunting of the liquid level control instrumentation 23.

It makes it easier for air bubbles in the liquid to rise. The liquid flows through the liquid flow hole 33
Since the liquid flows through the liquid to the circulation line 17 side, the liquid flow hole 33 has a rectifying effect.

FIG. 5 is also a sectional view of a main part showing another embodiment of the present invention. In this embodiment, a drop impact buffer member 34 is provided at the drop position of the liquid phase separated into gas and liquid by the liquid impact member 29. ing. The fall impact buffer member 34 is made of a guide plate with cushioning properties, but it may also be a perforated plate or other material.
According to this embodiment, since the falling blade of the liquid phase portion to the liquid reservoir portion 27 can be made extremely small, entrainment of air bubbles can be reliably prevented.

〔Effect of the invention〕

According to the present invention, the heated liquid is struck against the liquid impacting member to separate gas and liquid, and the liquid phase is dropped into the liquid reservoir and stored therein. As a result, no vortex is generated, reducing the risk of air bubbles being trapped. Therefore, cavitation does not occur in the circulation pump.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of a liquid concentrating device according to the present invention, and FIG.
The figure is an enlarged sectional view of the same main part, FIG. 3 is a sectional view of the main part of another embodiment, FIGS. 4 and 5 are sectional views of the main part showing other different embodiments, and FIG. FIG. 1 is an overall configuration diagram showing a liquid concentrator. 1... Heater, 2... Evaporator, 4... Heat exchanger tube, 1
7...Liquid circulation line, 18...Circulation pump, 27
...Liquid reservoir. 29...Liquid impact member, 30...Protrusion, 31...
Communication part. 32... Partition member, 33... Liquid flow hole, 34...
Fall impact cushioning material.

Claims (1)

[Claims] 1. A heater equipped with a liquid supply system, an evaporator provided in the upper part of this heater and equipped with a vapor condensation system, and an inlet of a liquid circulation line provided in the lower part of this evaporator. a liquid reservoir part communicating with the side, extending vertically into the heater, having an upper outlet opening upwardly into a lower part of the evaporator, and a lower inlet communicating with the outlet side of the liquid circulation line; The heat transfer tubes are connected to each other, a circulation pump provided in the liquid circulation line, and a liquid pump provided in the evaporation chamber at a position above the liquid level of the liquid reservoir and facing the upper opening of the heat transfer tube. A liquid concentrator equipped with this member. 2. A liquid concentrating device according to claim 1, wherein a protrusion is provided on the liquid impacting surface of the impacting member. 3. In claim 1 or 2, the lower part of the liquid reservoir is formed in the shape of a torus ring, the liquid circulation line is communicated with the bottom, and a plurality of communication parts are provided at approximately equal intervals. liquid concentrator. 4. A liquid concentrating device according to claim 1, 2, or 3, wherein the communication portion of the liquid reservoir with the liquid circulation line is located at a lower level than the upper opening of the heat transfer tube. 5. Claims 1, 2, 3, or 4, wherein a partition member is provided between the heat exchanger tube side of the liquid reservoir and the communication part side with the liquid circulation line, and this partition A liquid concentrator that has liquid flow holes in its parts. 6. In claim 1, 2, 3, 4, or 5, a fall impact buffer member is provided at the fall position of the liquid phase portion separated from gas and liquid by the impact member. Liquid concentrator.