KR100983656B1 - Evaporation condensation appratus for wastewater - Google Patents

Abstract

PURPOSE: A device for evaporating and concentrating waste is provided to reduce defects and power consumption by removing a pump for forcedly circulating waste. CONSTITUTION: An evaporation tank(100) has a waste storage unit(101), a heat exchange unit(110), and a steam generator(102). A heater(200) is arranged on the waste storage unit under the heat exchange unit. A waste supply pipe(310) is connected to the waste storage unit of the evaporation tank and supplies the waste. A concentrated waste exhaust pipe(320) is connected to the waste storage tank of the evaporation tank and exhausts the concentrated waste. A steam supply pipe(410) connects the steam generator and the heat exchanger. A condensate exhaust pipe(420) is connected to the heat exchanger and exhausts the concentrate. A steam compressor(430) is installed in the steam supply pipe and compresses the steam with high pressure.

Description

Evaporation Condensation Appratus for Wastewater

The present invention relates to an evaporation concentrator for wastewater, and more particularly, to an evaporation concentrator for wastewater capable of efficiently separating and recovering water and sludge contained in the wastewater, respectively.

In general, a method of purifying industrial wastewater or livestock wastewater is to store wastewater in one place and then administer a flocculant so that foreign substances such as suspended solids contained in the wastewater are entangled with each other and settle down. There is a method of filtering the waste water through a filtering screen device.

In case of the former of the wastewater treatment method, the sediment is forcibly settled by using a coagulant made of a chemical agent in order to sediment the foreign matter contained in the wastewater. Even when the coagulant is administered, the foreign matter contained in the wastewater is not aggregated and settled. Some remain rich in the wastewater, making it difficult to achieve the desired effect on the purification of the wastewater, especially when flocculants administered to the wastewater do not settle with sludge and remain in the wastewater, causing secondary contamination. There was a problem.

In addition, in the latter case, as a method of flowing the waste water to the screen device, the foreign material contained in the waste water is filtered. The second water treatment device is additionally installed because it is difficult to expect the effect of the foreign material being completely filtered while passing through the screen device. There was a problem that should be.

On the other hand, since industrial cutting oil is generally used after diluting with water, it was necessary to separate the wastewater for reuse or disposal after use. However, the above-described wastewater treatment method was difficult to adopt due to various problems introduced above.

Therefore, in recent years, a technology for separating water and sludge by evaporating wastewater has been studied, and a representative example thereof is disclosed in Korean Patent Laid-Open Publication No. 2004-0057843 (hereinafter referred to as 'prior art').

Hereinafter, an evaporative wastewater purification apparatus according to the prior art will be schematically described with reference to FIGS. 1A and 1B.

As shown in the drawing, the evaporative wastewater purification apparatus according to the prior art is configured to increase the pressure by dividing the internal space of the evaporation tank 1 and the internal space of the evaporation tank 1 into a sealed structure in which the heater 2 is mounted. A waste water supply tank 10 to which a space 6 and a reduced pressure space 7 are formed, and a predetermined amount of wastewater injected into the evaporation tank 1 is supplied, and a predetermined amount of wastewater injected into the evaporation tank 1 A pump 20 for feeding pressure to the wastewater supply tank 10 and a pressure-reducing space 7 installed vertically downward from the wastewater supply tank 10, and the wastewater supplied to the wastewater supply tank 10 has an outer peripheral surface. A plurality of evaporation tubes 30 which are evaporated by steam while riding and flowing down, and a collection tank 40 mounted to the lower end of the evaporation tubes 30 installed in a plurality and in communication with the plurality of evaporation tubes 30; A high pressure fan 50 which evaporates from the evaporation tube 30 and suction-transduces water vapor present in the decompression space 7 into the boosting space 6; A cyclone-type condensation tank 60 into which the water vapor pumped from the booster space 6 to the evaporation pipe 30 and the collection tank 40 by the pressure fan 50 is introduced through the pressure pipe 61 and condensed into purified water; The inflow pipe 5 into which the purified water condensed in the condensation tank 60 is introduced and the waste water is introduced is configured in a coil form to form a heat exchange tank 70.

However, the evaporative wastewater purification apparatus according to the prior art evaporates the water contained in the wastewater in the process of repeatedly circulating the wastewater heated by the heater along the drain pipe, the discharge pipe, the wastewater supply tank, the evaporation pipe, the wastewater There was a disadvantage in that the operating cost is increased because the power of the pump is required to circulate.

In addition, since the viscosity gradually increases in the course of wastewater concentration, the working pressure of the pump is also increased in proportion to the power consumption.

In addition, during the flow of wastewater through the discharge hole formed between the wastewater supply tank and the evaporation tube, the water of the wastewater evaporates and the concentrated sludge is deposited on the surface of the evaporation tube so that the discharge hole may be closed. Since sludge removal had to be performed periodically, there was a problem in that the cost for the maintenance was increased and the wastewater treatment capacity was greatly reduced due to the work space for maintenance.

The present invention has been made to solve the above problems, an object of the present invention is to quickly separate the water and sludge through the convection circulation of the waste water in the evaporation tank, respectively, can significantly reduce the power consumption accordingly In addition, the present invention provides an evaporative concentration device for wastewater that can further reduce energy for heating wastewater.

In order to achieve the above object, the evaporation and concentration apparatus for wastewater according to the present invention,

An evaporation tank in which a wastewater storage unit, a heat exchanger, and a steam generator are sequentially formed from a lower portion to an upper portion;

A heater disposed in the wastewater storage unit below the heat exchanger;

A wastewater supply pipe communicating with a wastewater storage unit of the evaporation tank and supplying wastewater;

A concentrated wastewater discharge pipe communicating with the wastewater storage unit of the evaporation tank and discharging the concentrated wastewater;

A steam supply pipe communicating with the steam generator and the heat exchanger;

A condensate discharge pipe communicating with the heat exchanger to discharge condensate; And

Installed in the steam supply pipe includes a steam compressor for compressing the steam at high pressure,

The heat exchange part is composed of a waste water circulation pipe for circulating the waste water by communicating between the waste water storage unit and the steam generating unit, and a steam inlet unit formed around the waste water circulation tube, and the steam inlet unit communicates with the steam supply pipe and the condensate discharge tube. It is characterized by.

Here, the wastewater circulation pipe is composed of a wastewater rising pipe for raising the wastewater, and a wastewater lowering pipe for lowering the wastewater, wherein the wastewater rising pipe is configured to be configured in plural on the outside of the wastewater dropping pipe.

In addition, the wastewater circulation pipe is composed of a wastewater riser pipe for raising the wastewater, and a wastewater dropping pipe for descending the wastewater, wherein the wastewater dropping pipe is disposed on the outside of the wastewater riser tube and is characterized in that the communication structure. .

In addition, the heater is characterized in that it is disposed directly below the wastewater riser.

In addition, the wastewater evaporation and concentration device is characterized in that the heat exchanger for heat exchange between the wastewater supply pipe and the condensate discharge pipe is additionally installed.

In addition, the steam generator of the evaporation tank is characterized in that the temperature sensor for detecting the saturation temperature of the waste water is installed.

In addition, the vapor generating unit of the evaporation tank is characterized in that the water level detection sensor for detecting the water level of the waste water.

In particular, the heater is characterized in that to generate less calories at the time of the enrichment operation than when the wastewater is concentrated.

On the other hand, the vapor generating portion of the evaporation tank is characterized in that the gas-liquid separator is formed.

In addition, the heat exchanger is wound in a spiral, characterized in that the waste water and condensate is composed of a double pipe to move in opposite directions to each other.

The double pipe may include a first communication pipe communicating with the wastewater supply pipe, and a second communication pipe communicating with the condensate discharge pipe and surrounding an outer circumferential surface of the first communication pipe.

According to the present invention having the above-described configuration, not only can the wastewater efficiently separate and recover the water and sludge contained in the wastewater through convection circulation in the evaporation tank, but also to artificially circulate the wastewater. Since the configuration of the pump can be omitted, failure and power consumption can be greatly reduced, and heating energy of the heater can also be greatly reduced.

Figure 1a is a cross-sectional view showing the configuration of an evaporative wastewater purification apparatus according to an embodiment of the prior art.
FIG. 1B is a partially enlarged view of FIG. 1A. FIG.
Figure 2 is a cross-sectional view showing the configuration of the evaporation concentrator for wastewater according to an embodiment of the present invention.
3 is a cross-sectional view of the heat exchanger of FIG.
4 is a cross-sectional view showing an evaporation and concentration apparatus for wastewater according to another embodiment of the present invention.
5 is a cross-sectional view illustrating a configuration of the heat exchanger of FIG. 2.

Hereinafter, with reference to the accompanying Figures 2 to 5 will be described in detail a preferred embodiment of the present invention.

As shown, the evaporation concentrator 1000 for wastewater according to the present invention is an evaporation tank 100 in which a wastewater storage unit 101, a heat exchanger 110, and a steam generator 102 are sequentially formed from a lower side to an upper side. And, the heater 200 disposed in the wastewater storage unit 101 below the heat exchange unit 110 and the wastewater supply pipe 310 is connected to the wastewater storage unit 101 of the evaporation tank 100 to supply the wastewater. And a concentrated wastewater discharge pipe 320 communicating with the wastewater storage unit 101 of the evaporation tank 100 and discharging the concentrated wastewater, and a steam supply pipe communicating the steam generating unit 102 and the heat exchange unit 110 ( 410, a condensate discharge pipe 420 communicating with the heat exchanger 110 to discharge condensate, and a steam compressor 430 installed at the steam supply pipe 410 to compress water vapor at a high pressure.

First, the evaporation tank 100 is a component for storing and circulating waste water and generating steam.

Specifically, the interior of the evaporation tank 100 is a wastewater storage unit 101 for receiving or discharging wastewater, a steam generator 102 for escaping water with water vapor contained in the wastewater, and the wastewater storage unit. The heat exchanger 110 is formed between the 101 and the steam generator 102.

In the steam generator 102, a gas-liquid separator 120 for preventing the evaporated water vapor from being discharged along with the water vapor in the process of escaping the waste water is formed.

Here, the gas-liquid separator 120 is shown as a structure in which a plurality of plates bent in a zigzag shape from the bottom to the top at a predetermined interval, but not necessarily limited thereto and may adopt various known configurations and structures. have.

The heat exchange unit 110 serves to generate condensate while simultaneously generating steam through heat exchange while convection circulation of waste water stored in the evaporation tank 100.

To this end, the heat exchange part 110 is formed between the wastewater storage unit 101 and the steam generating unit 102 and the wastewater circulation pipe 111 for circulating the wastewater, and formed around the wastewater circulation pipe 111. A steam inlet 112 is provided.

The wastewater circulation pipe 111 is divided into a wastewater rising pipe 111a for raising the wastewater and a wastewater falling pipe 111b for lowering the wastewater. As shown in FIG. 2, the wastewater rising pipe 111a is It may be made of a plurality disposed on the outside of the waste water down pipe (111b), in this case waste water down pipe (111b) uses a large diameter tube so that heat exchange is not made well.

However, the arrangement structure of the wastewater rising pipe 111a and the wastewater falling pipe 111b is exemplified as an example, and is not limited thereto. As shown in FIG. 4, the wastewater falling pipe 111b is a wastewater rising pipe. The steam generating unit 102 and the wastewater storage unit 101 may be formed to communicate with each other in the upper and lower portions in a state disposed outside the pipe 111a.

In addition, the steam inlet 112 is in communication with the steam supply pipe 410 and the condensate discharge pipe 420, which will be described later.

Looking at the convective circulation of the wastewater in the evaporation tank 100, the wastewater of the wastewater rise pipe (111a) is heated to saturation temperature and boiled, the density of water vapor bubbles and the wastewater is mixed and the density is lowered, wastewater downpipe (111b) Wastewater is higher than the wastewater of the wastewater rise pipe (111a) because the heat exchange is not made. Therefore, buoyancy effect due to the difference in density occurs, the waste water in the evaporation tank 100 from the wastewater storage unit 101 to the wastewater riser (111a), the wastewater riser (111a) in the steam generator ( 102, the entire convective circulation from the steam generator 102 to the wastewater downcomer 111b and the wastewater downcomer 111b to the wastewater storage 101 occurs continuously.

In addition, the steam generator 102 of the evaporation tank 100 is preferably provided with a temperature sensor 130 for detecting the saturation temperature of the waste water and a water level sensor 140 for detecting the water level.

Accordingly, according to the current temperature of the wastewater detected by the temperature sensor 130, the heat amount of the heater 200 can be added or decreased, or the rotation speed of the steam compressor 430 can be added or decreased, and the water level sensor 140 The amount of wastewater supplied through the wastewater supply pipe 310 may be adjusted according to the sensed wastewater level.

On the other hand, the heater 200 is to heat the waste water stored in the evaporation tank 100 to the saturation temperature (boiling point), at least one or more is disposed directly below the waste water riser (111a) of the evaporation tank (100). .

Of course, the heater 200 is installed directly below the waste water riser (111a) is installed in a suitable position that does not interfere with the flow of waste water in the convection circulation.

Here, the heater 200 emits a high amount of heat to heat the wastewater to the saturation temperature at the beginning of the wastewater concentration operation, but once the concentration operation is in progress to the depth from the surface of the wastewater to the bottom of the heat exchange unit 110 The amount of heat only needs to be released as the saturation temperature increases according to the pressure difference of the wastewater generated by the wastewater.

That is, the steam compressor 430, which will be described later, compresses the water vapor converted by the vaporization of water in the waste water to high pressure and supplies the steam water condensed in the process of supplying it to the steam inlet 112 of the heat exchange unit 110. Since the wastewater passing through the 111a is heated, the wastewater in the wastewater riser 111a is heated and boiled to a saturation temperature according to the water depth (if the water depth is high, the saturation temperature is also high) and rises to the steam generator 102. The reached wastewater flashes as the water pressure decreases, while the temperature drops to the saturation temperature of the water surface.

Subsequently, since the temperature at which the wastewater reaching the wastewater storage unit 101 without being heated in the wastewater dropping pipe 111b flows into the wastewater rising pipe 111a is lower than the saturation temperature corresponding to the water depth, the wastewater rises. The lower portion of the pipe (111a) there is a section in which the temperature of the waste water gradually increases until boiling does not occur and reaches the saturation temperature corresponding to the depth, which is inefficient in the design and manufacture of the heat exchange unit 110 to be.

Therefore, by applying the heat amount only by the saturation temperature increase according to the pressure difference of the wastewater generated by the depth from the surface of the wastewater to the lower end of the heat exchanger 110 by the heater 200 from the lower end of the heat exchanger 110. Bubbles are generated by boiling, and the amount of water vapor generated in the same heat exchange area is dramatically increased.

In addition, the waste water supply pipe 310 is in communication with the waste water storage unit 101 of the evaporation tank 100 serves to supply the waste water from the outside.

The heat exchanger 500 is supplied through the waste water supply pipe 310 in the process in which the water vapor supplied to the steam inlet 112 of the heat exchanger 110 is converted into condensed water and recovered as raw water along the condensate discharge pipe 420. It performs a heat exchange action to preheat the waste water.

As shown in FIG. 5, the heat exchanger 500 is wound spirally from the inner end of the case body 510 and the inner side of the case body 510 to the other side, and the waste water and the condensate move along different passages. It consists of a double pipe (520). However, the heat exchanger 500 may be configured such that the case body 510 is omitted and the double tube 520 is exposed as it is.

The double pipe 520 communicates with the first communication pipe 521 communicating with the wastewater supply pipe 310, and the second communication pipe surrounding the outer circumferential surface of the first communication pipe 521 in an outer radial direction while communicating with the condensate discharge pipe 420. 522.

That is, the wastewater supplied to the evaporation tank 100 through the wastewater supply pipe 310 moves along the first communication pipe 521 and preheats the wastewater in the process of discharging the condensed water discharged through the second communication pipe 522. Heat exchange effect is achieved. At this time, the waste water and the condensate can maximize the heat exchange action by the counter flow (counter flow) action to move along the mutually opposite movement path.

In addition, the concentrated wastewater discharge pipe 320 is in communication with the bottom surface of the wastewater storage unit 101 of the evaporation tank 100, and serves to discharge the sludge of the concentrated wastewater.

On the other hand, the steam supply pipe 410 and the condensate discharge pipe 420, respectively, serves to supply water vapor in the steam inlet 112 of the heat exchange unit 110 and discharge the condensed water condensed.

In particular, at any point of the steam supply pipe 410 is provided with a steam compressor 430 for compressing the water vapor introduced from the steam generating unit 102 to a high pressure.

The steam compressor 430 serves to boil the wastewater passing through the wastewater riser 111a of the heat exchanger 110 by condensing water vapor on the outer surface of the wastewater riser 111a by increasing the pressure of the steam.

This, the steam compressor 430 is connected to a separate control unit (not shown), when the flow rate detected by the flow rate check sensor (not shown) for checking the inflow of water vapor or condensate water is less than a predetermined amount to stop the operation and concentrated Waste water will be discharged.

Of course, after setting the operation time of the steam compressor 430 in advance, when the operation time is reached, the operation may be stopped and the concentrated wastewater may be discharged.

The temperature sensor 130 and the water level sensor 140 is also electrically connected and programmed to control the operation.

Hereinafter, the operation of the wastewater evaporation and concentration apparatus 1000 according to the embodiment of the present invention will be described in detail.

First, when the wastewater for concentration is supplied into the evaporation tank 100 through the wastewater supply pipe 310, the wastewater is the wastewater storage unit 101, the heat exchanger 110 and the steam generator 102 of the evaporation tank 100 In the process of being sequentially filled up to a predetermined level of the wastewater is detected by the water level sensor 140, the supply is stopped.

Thereafter, the heater 200 disposed below the heat exchange unit 110 operates to heat the wastewater in the wastewater storage unit 101 to a saturation temperature.

Wastewater heated to the saturation temperature by the heater 200 is initially supplied when the steam escaping from the steam generator 102 by the steam compressor 430 is supplied to the steam inlet 112 of the heat exchanger 110. Since the temperature of the steam inlet 112 is lower than the saturation temperature of the wastewater, the exothermic energy of the heater 200 increases the temperature of the steam inlet 112 to the saturation temperature of the wastewater.

Then, when the temperature of the steam inlet 112 exceeds the saturation temperature of the waste water, the high-pressure steam supplied by the steam compressor 430 is condensed on the outer surface of the waste water rise pipe (111a) and the waste water rise pipe (111a) The wastewater passing through is boiled, and the wastewater in the wastewater riser 111a is heated and boiled up to a saturation temperature according to the water depth, and the wastewater rising to reach the steam generator 102 is reduced in pressure as the water pressure decreases. Temperature drops to the saturation temperature of the water surface.

Subsequently, since the temperature of the wastewater which reaches the wastewater storage unit 101 without being heated in the wastewater dropping pipe 111b flows into the wastewater rising pipe 111a is lower than the saturation temperature corresponding to the water depth, the heater 200 Bubbles are generated by boiling from the lower end of the heat exchange part 110 by applying only the heat amount by the saturation temperature increase according to the pressure difference of the waste water generated by the depth from the surface of the waste water to the lower end of the heat exchange part 110 by This is done.

Therefore, the wastewater in the evaporation tank 100 from the wastewater storage unit 101 to the wastewater riser 111a, the wastewater riser 111a to the steam generator 102, and the steam generator 102 wastewater downpipe At 111b, the entire convective circulation from the wastewater down pipe 111b to the wastewater storage 101 occurs continuously.

On the other hand, the water vapor vaporized in the steam generator 102 of the evaporation tank 100 is passed to the steam supply pipe 410 after passing through the gas-liquid separator 120. At this time, the water vapor is compressed to high pressure by the operation of the steam compressor 430 installed in the steam supply pipe 410 and then ejected to the steam inlet 112 of the heat exchange unit 110 again.

The water vapor ejected through the steam compressor 430 condenses on the outer surface of the wastewater riser 111a of the heat exchanger 110 to boil the wastewater passing through the wastewater riser 111a, thereby heating the wastewater. The heating energy of the heater 200 can be greatly reduced.

In addition, the steam that heated the wastewater circulation pipe 111 is changed into condensed water by a heat exchange action, and the changed condensed water is discharged after passing through the condensed water discharge pipe 420 and the second communication tube of the heat exchanger.

On the other hand, since most of the wastewater that has undergone convective circulation for a predetermined time in the evaporation tank 100 evaporates water vapor, only sludge of the concentrated wastewater remains, and the concentrated sludge is discharged through the concentrated wastewater discharge pipe 320. do.

The opening of the concentrated wastewater discharge pipe 320 may be controlled to be automatically released when the flow rate of the water vapor flowing into the steam compressor 430 is repeatedly discharged over a predetermined time from the time point of the concentration operation. have.

In addition, the operation of the heater 200 and the steam compressor 430 and the supply of wastewater may be controlled by the temperature sensor 130 or the water level sensor 140 installed in the evaporation tank 100.

That is, when the water level of the wastewater is lowered in the course of concentrating the wastewater, the wastewater can be supplied from the wastewater supply pipe 310 by a controller (not shown), and the wastewater supplied from the wastewater supply pipe 310 is Since it contains a large amount of water naturally moves to the upper side of the concentrated sludge, and absorbs heat from the concentrated sludge and at the same time the temperature is sensed by the temperature sensor 130 from the heater 200 and the steam compressor 430 It is possible to reach a saturation temperature quickly by receiving a predetermined energy.

As such, the evaporation and concentrating device 1000 for wastewater according to the present invention can efficiently separate and recover the water and sludge contained in the wastewater through convection circulation in the wastewater 100. In addition, since the configuration of the pump for artificially circulating the waste water can be omitted, the failure rate and power consumption can be greatly reduced, and the heating energy of the heater 200 can also be greatly reduced.

100: evaporation tank
101: wastewater storage unit
102: steam generator
110: heat exchanger
111: wastewater circulation pipe
111a: wastewater riser
111b: wastewater down pipe
112: steam inlet
120: gas-liquid separator
200: heater
310: wastewater supply pipe
320: concentrated wastewater discharge pipe
410 steam supply pipe
420: condensate discharge pipe
430: steam compressor
500: heat exchanger
510: case body
520: double pipe
521: first communication tube
522: the second communication tube

Claims (11)

An evaporation tank in which a wastewater storage unit, a heat exchanger, and a steam generator are sequentially formed from a lower portion to an upper portion;
A heater disposed in the wastewater storage unit below the heat exchanger;
A wastewater supply pipe communicating with a wastewater storage unit of the evaporation tank and supplying wastewater;
A concentrated wastewater discharge pipe communicating with the wastewater storage unit of the evaporation tank and discharging the concentrated wastewater;
A steam supply pipe communicating with the steam generator and the heat exchanger;
A condensate discharge pipe communicating with the heat exchanger to discharge condensate; And
Installed in the steam supply pipe includes a steam compressor for compressing the steam at high pressure,
The heat exchange part is composed of a waste water circulation pipe for circulating the waste water by communicating between the waste water storage unit and the steam generating unit, and a steam inlet unit formed around the waste water circulation tube, and the steam inlet unit communicates with the steam supply pipe and the condensate discharge tube. Evaporation and concentration device for wastewater, characterized in that.
The method of claim 1,
The wastewater circulation pipe is composed of a wastewater rising pipe for raising the wastewater and a wastewater falling pipe for lowering the wastewater, and the wastewater rising pipe is composed of a plurality of wastewater lowering pipes disposed on the outside of the evaporation concentration. Device.
The method of claim 1,
The wastewater circulation pipe is composed of a wastewater riser pipe for raising the wastewater and a wastewater dropping pipe for lowering the wastewater, wherein the wastewater dropping pipe is disposed on the outside of the wastewater riser pipe to communicate with the wastewater. Evaporative concentration system.
The method of claim 3,
The heater is an evaporation concentrator for wastewater, characterized in that disposed directly below the wastewater riser.
4. The method according to any one of claims 1 to 3,
And a heat exchanger for exchanging the wastewater supply pipe and the condensate discharge pipe to the wastewater evaporation concentrator.
4. The method according to any one of claims 1 to 3,
Evaporation concentrator for waste water, characterized in that the temperature generating sensor for detecting the saturation temperature of the waste water is installed in the steam generator of the evaporation tank.
4. The method according to any one of claims 1 to 3,
Evaporation concentration device for waste water, characterized in that the water level detection sensor for detecting the water level of the waste water is installed in the steam generator of the evaporation tank.
4. The method according to any one of claims 1 to 3,
The heater is an evaporation concentrator for wastewater, characterized in that to generate less heat at the time of the enrichment operation than when the wastewater is prepared for the enrichment operation.
4. The method according to any one of claims 1 to 3,
Evaporation concentrator for waste water, characterized in that the vapor-liquid separator is formed in the steam generator of the evaporation tank.
The method of claim 5,
The heat exchanger is spirally wound, the evaporation concentrator for wastewater, characterized in that consisting of a double pipe in which the wastewater and condensate move in opposite directions.
The method of claim 10,
The double pipe is an evaporation concentrating device for wastewater, characterized in that the first communication pipe communicating with the wastewater supply pipe, and the second communication pipe which is in communication with the condensate discharge pipe and wraps around the outer circumferential surface of the first communication pipe.

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