Separation tower for treating condensate and method thereof

Abstract

In order to make up for the deficiencies of the prior art, such as high investment, high energy consumption, need to use organic phase as an extractant, and high safety requirements, the present invention provides a separation tower for treating condensate, the water separation tower including a tower body, an evaporation unit for purifying the condensate is provided in the tower body, and a vacuum pump is connected to the final effect condensation unit, the beneficial effects of the present invention are as follows: 1) gravity is utilized, and intermediate pumps are omitted, so that power costs and combined control systems are saved; 2) the pressure difference between each effect is designed, and the thermal energy provided by the first effect is utilized for continuous evaporation, so that the purpose of separation is achieved, and the subsequent effect does not require a heat source from the outside; 3) the integration degree is high, the sealing property is good, and the subsequent vacuum system is easy to realize, the subsequent vacuum system is small, the energy consumption is low, the equipment occupation area is small, the construction and installation costs are low, and the operation is easy.

Description

[Technical field]

[0001] The present invention relates to a water separation tower, in particular to a water separation tower for the purification of exhaust gas condensate in a high purity terephthalic acid (English abbreviation is PTA) short process. [Background technology]

[0002] Water circulation in the production process of PTA equipment is the key to realizing the short process, among which, the steam and oxidation exhaust gas discharged from the dehydration tower enter the condenser and condense to produce a large amount of condensate, which contains a certain amount of acetic acid and PT acid (p-toluic acid), which affects the reuse of condensate, and the acetic acid in the condensate not only aggravates the corrosion of the equipment of the purification unit, but also affects the quality of the product when the condensate is used as the cleaning water of the purification unit. In order to improve the water quality of the condensate, the traditional short process generally uses an extraction device, which requires high investment, high energy consumption, and needs to use organic phase as an extractant, and has high safety requirements. Summary of the Invention

[0003] SUMMARY OF THE DISCLOSURE In order to solve the problems in the above-mentioned processing techniques, the present invention provides a novel tower-type water separation tower and separation method thereof which is low in energy, highly efficient and inherently safe.

[0004] A separation tower for treating condensate includes a tower body, an evaporation unit for purifying the condensate is provided in the tower body, a final effect condensing unit is provided below the evaporation unit, and a vacuum pump is connected to the final effect condensing unit;

[0005] The evaporation unit includes a first effect evaporation unit and a second effect evaporation unit, or further includes a multi-effect evaporation unit, for example, a third effect evaporation unit, a fourth effect evaporation unit, or a fifth effect evaporation unit, and the first effect evaporation unit includes a condensate inlet and a first heat exchange chamber, and above the first heat exchange chamber, a first mist eliminator is provided for removing mist from the vapor phase generated after the condensate exchanges heat, and a first downcomer is provided for the liquid phase to pass through and flow to the next effect evaporation unit, and a first vapor passage is connected to the first mist eliminator for the vapor phase to enter the next effect evaporation unit. the second effect evaporator unit includes a second heat exchange chamber, a second mist eliminator used for removing mist from the gas phase generated after the condensate has undergone heat exchange, and a second downcomer through which the liquid phase passes, the second mist eliminator is connected to a second steam passage, a second loop device is provided at the bottom of the second downcomer, a first condensate passage through which the condensate after heat exchange flows to the next effect member is provided below the second heat exchange chamber, and a first U-shaped tube is provided at the bottom of the first condensate passage.

[0006] The first loop-shaped device is located between the second heat exchange chamber and the second mist eliminator, and serves to separate the first effect evaporation unit and the second effect evaporation unit and create a pressure difference between them. At the same time, the first loop-shaped device is also a self-evaporation device, and is similarly a loop-shaped device for the second loop-shaped device and other effect evaporation units.

[0007] The first U-tube can direct the condensate to the bottom of the tower and, similar to the loop device, also serves to separate each effect evaporator unit from the next effect evaporator unit, creating a pressure difference between the two.

[0008] The first effect evaporation unit has a heat source provided from the outside, and the heat source can use low pressure steam of 0.05 to 0.5 MPa as a heating medium, and can also use non-clean heat sources such as industrial waste heat.

[0009] Additionally, a purified water storage area is provided below the last effect condensing unit.

[0010] Furthermore, the condensate inlet is provided at the bottom of the first effect evaporative unit.

[0011] Further, the external heat source is provided by an external heat vapor in a heat exchange line introduced into the first heat exchange chamber.

[0012] The object of the present invention is to provide a method for treating condensate, said method comprising the steps of:

[0013] 1) opening a vacuum pump, injecting condensate into the first effect evaporative unit through a condensate inlet, and introducing a heat source for heat exchange outside the pipe in the first heat exchange chamber;

[0014] 2) the condensate and the heat source exchange heat in the first heat exchange chamber, the condensate is divided into a first gas phase and a first liquid phase, the first gas phase passes through a first mist eliminator and then enters the first steam passage, and then enters the next effect evaporation unit through the first steam passage; the first liquid phase flows from the first downcomer through the first loop device to the next effect evaporation unit and becomes a first concentrated liquid phase; the first concentrated liquid phase realizes self-evaporation in the first loop device; then the generated gas phase enters the second mist eliminator and then enters the second steam passage, and the liquid phase that does not self-evaporate enters the next effect heat exchange chamber to perform heat exchange; During the downward flow of the first concentrated liquid, it first collects in the first loop device. When it collects to a certain extent, it separates the first effect evaporator unit from the second evaporator unit. The vacuum pump keeps working, so that a pressure difference is formed between the first effect evaporator unit and the second evaporator unit. As a result, in the first loop device, the pressure at the inlet of the first effect evaporator unit is greater than the pressure at the outlet of the second evaporator unit. Therefore, the first liquid phase realizes self-evaporation at the outlet of the second evaporator unit. heat exchange is completed between a high temperature heat source outside the conduit in the heat exchange chamber and a low temperature liquid phase within the conduit;

[0015] 3) the first gas phase enters the outside of the pipe in the second heat exchange chamber through the first steam passage, and exchanges heat with the first concentrated liquid phase as a heat source for the second heat exchange; after the heat exchange is completed, the first gas phase condenses and becomes condensate, and flows downward through the first condensate passage into the first U-shaped tube; the first concentrated liquid obtains a second gas phase and a second liquid phase after the second heat exchange; the second gas phase flows upward through the second mist eliminator into the second steam passage, and then into the next effect evaporating unit for heat exchange as a heat source or into the last effect condensing unit; the second liquid phase flows through the second downcomer into the second loop device, and flows to the next effect evaporating unit, or undergoes self-evaporation; In this process, when the first condensate flows downward and enters the first U-tube, it will first collect in the first U-tube, and when it collects to a certain extent, it will separate the second evaporator and the next effect element, thus forming a pressure difference;

[0016] 4) Finally, the gas phase enters a last-effect condensation unit to be condensed and mixed with the condensate to become purified water, which can be discharged; the concentrated water remaining after the multiple-effect evaporation is discharged for further treatment; and finally, the purified water is separated from other substances.

[0017] In addition to the first effect evaporation unit, the subsequent evaporation units do not require an external heat source for the second heat exchange.

[0018] Preferably, a third effect evaporator unit may be further provided, the third effect evaporator unit including a third heat exchange chamber, a third gas phase outlet and a third liquid phase outlet provided above the third heat exchange chamber, a third mist eliminator provided above the third gas phase outlet, the third mist eliminator communicating with a third steam passage, the third liquid phase outlet communicating with a third downcomer, a third loop device provided at the bottom of the third downcomer, a second condensate passage leading to an upper part of a fourth heat exchange chamber connected to the bottom of the third heat exchange chamber, an end of the second steam passage communicating with the third heat exchange chamber, an outlet of the second loop device located above the third heat exchange chamber, a second U-shaped tube provided at the bottom of the second condensate passage, the condensate remaining in the second U-shaped tube serves to separate the third effect evaporator unit and the fourth effect evaporator unit, and at the same time creates a pressure difference between the two.

[0019] The principle of separation of the gas phase and the liquid phase in the third effect evaporator unit is the same as that in the second effect evaporator unit.

[0020] Preferably, a fourth effect evaporation unit may be further provided, the fourth effect evaporation unit including a fourth heat exchange chamber, a fourth gas phase outlet and a concentrated water outlet provided above the fourth heat exchange chamber, a fourth mist eliminator provided above the fourth gas phase outlet, the fourth mist eliminator communicating with a fourth steam passage, the concentrated water remaining through continuous evaporation can be discharged from the concentrated water outlet, the bottom of the fourth heat exchange chamber communicating with a third condensate passage leading to the last effect condensing unit, a third U-shaped tube provided at the bottom of the third condensate passage, the condensate remaining in the third U-shaped tube serving to separate the fourth effect evaporation unit and the last effect condensing unit, and at the same time causing a pressure difference between the two.

[0021] During the purification process, the vacuum pump located at the bottom of the tower is constantly working, combined with the partitioning action of the U-shaped tube and loop-shaped device between each evaporation unit, so that the pressure in the tower gradually decreases from top to bottom, and the vacuum degree gradually increases from top to bottom. There is a pressure difference between each effect evaporation unit, which improves the evaporation speed; at the same time, the present invention utilizes the effect of gravity, and the entire purification process proceeds gradually from top to bottom.

[0022] In the purification process, H2O is continuously evaporated into the gas phase in each effect, and then enters the next effect through the steam passage, and at the same time, carries heat to exchange with the liquid phase of the next effect evaporation unit. The condensate after heat exchange flows downward through the condensate passage, and finally reaches the last effect condensation unit, and can be discharged as purified water. In the evaporation process of each effect evaporation unit, water (boiling point 100°C at atmospheric pressure) is continuously evaporated into the gas phase, and other substances such as acetic acid (boiling point 117.9°C at atmospheric pressure), PT acid (boiling point 274-275°C at atmospheric pressure) remain for continuous concentration, and can finally be discharged as concentrated water.

[0023] Of course, other chemicals may also be required to treat the condensate during production processes, which may also be applied to the apparatus and method.

[0024] The beneficial effects of the present invention are as follows: 1) gravity is utilized, and the gas flows downward in stages into the effect members, eliminating the need for intermediate pumps and saving on power costs and combined control systems; 2) the pressure difference between each effect member is cleverly designed, and the thermal energy provided by the primary effect member is utilized for continuous evaporation, thereby achieving the purpose of separation, and the subsequent effect members do not require a heat source from the outside; 3) the pipelines between all the units are all arranged inside the tower, and no pipelines are arranged outside the tower, which results in high integration, excellent sealing, easy to realize vacuum, small subsequent vacuum system, low energy consumption, small equipment footprint, low construction and installation costs, and easy operation. [Brief description of the drawings]

[0025] [Figure 1] FIG. 2 is a structural schematic diagram of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] The invention will now be further elucidated and explained with reference to the drawings, in which:

[0027] As shown in FIG. 1, in this embodiment, the water separation tower includes a total of four evaporation units.

[0028] The water separation tower for treating condensate in the preparation process of high purity terephthalic acid includes a tower body, a first effect evaporating unit 1 for purifying the condensate, a second effect evaporating unit 2 provided below the first effect evaporating unit 1, a third effect evaporating unit 3 provided below the second effect evaporating unit 2, a fourth effect evaporating unit 4 provided at the bottom of the third effect evaporating unit 3, and a final effect condensing unit 5 provided below the fourth effect evaporating unit 4, which are arranged in order from top to bottom, and sealing heads are provided at the top and bottom of the tower body to maintain the sealing property of the tower body.

[0029] A non-condensable gas outlet 03 is provided in each effect evaporating unit to discharge non-condensable gas, and is used to adjust the air pressure in each effect evaporating unit in the tower as needed.

[0030] A partition plate is provided between each of the effect evaporation units.

[0031] The first effect evaporative unit 1 includes a first heat exchange chamber 11, a first gas phase outlet and a first liquid phase outlet are provided above the first heat exchange chamber 11, a first mist eliminator 12 is provided above the first gas phase outlet, the first mist eliminator 12 is connected to a first vapor passage 13 (the first vapor passage 13 is preferably located within the tower), the first liquid phase outlet is connected to a first downcomer 14, a first loop device 15 is provided at the bottom of the first downcomer 14, and a condensate inlet 16 is provided at the bottom of the first effect evaporative unit 1.

[0032] Preferably, the first effect evaporation unit 1 is provided with a steam inlet 01 and a steam outlet 02 for providing a heat source to the first effect evaporation unit 1 to complete the heat exchange, and the heat source can use low pressure steam of 0.05 to 0.5 MPa as a heating medium, and further can use a non-clean heat source such as industrial waste heat.

[0033] In the purification process of the first effect evaporator unit 1, the condensate to be purified enters the bottom of the first effect evaporator unit 1 through the condensate inlet 16, and then undergoes heat exchange in the first heat exchange chamber 11. After heat exchange, a part of the condensate vaporizes into the first gas phase, passes through the first mist eliminator 12 from the first gas phase outlet, and then enters the first steam passage 13, and enters the second effect evaporator unit 2 through the first steam passage 13 to be used as the heat source for heat exchange in the next effect evaporator unit. The other part of the condensate that does not change into the gas phase enters the first liquid phase inlet into the first downcomer 14 in the form of the first liquid phase, and then flows into the second effect evaporator unit 2 through the first loop device 15 to become the first concentrated liquid. The first concentrated liquid phase enters the first loop device 15 and partially evaporates, and then enters the second steam passage 23 through the second mist eliminator 22. The part that does not evaporate enters the next effect member to perform heat exchange.

[0034] In the above process, hot steam enters the pipe of the first heat exchange chamber 11 from the steam inlet 01 and exchanges heat with the condensate. After the heat exchange, the cooled steam is discharged from the steam outlet 02. The temperature of the first effect evaporative unit 1 is about 100°C (95-105°C), and the pressure of the first effect evaporative unit 1 corresponds to the outside pressure.

[0035] The second effect evaporator unit 2 includes a second heat exchange chamber 21, a second gas phase outlet and a second liquid phase outlet are provided above the second heat exchange chamber 21, a second mist eliminator 22 is provided above the second gas phase outlet, the second mist eliminator 22 is connected to a second vapor passage 23 (preferably located in the tower), the second liquid phase outlet is connected to a second downcomer 24, a second loop device 25 is provided at the bottom of the second downcomer 24, a first condensate passage 26 (preferably located in the tower) leading to the top of a third heat exchange chamber 31 is connected to the bottom of the second heat exchange chamber 21, a first U-shaped tube 27 is provided at the bottom of the first condensate passage 26, and the condensate remaining in the first U-shaped tube 27 serves to separate the second effect evaporator unit 2 and the third effect evaporator unit 3, and at the same time causes a pressure difference between the two. The end of the first steam passage 13 communicates with the second heat exchange chamber 21 , and the outlet of the first loop device 15 is located above the second heat exchange chamber 21 .

[0036] The first liquid phase remains in the first loop device 15, and when the first liquid phase is collected to a certain extent, it acts as a partition between the first effect evaporating unit 1 and the second effect evaporating unit 2. As a result, there is a certain pressure difference between the first effect evaporating unit 1 and the second effect evaporating unit 2 (a vacuum pump is connected to the bottom of the tower), and the pressure in the second effect evaporating unit 2 is lower than that of the first effect evaporating unit 1. Therefore, in the first loop device 15, the pressure at the outlet of the second effect evaporating unit 2 is lower than the pressure at the inlet of the first effect evaporating unit 1 (i.e., the liquid phase in the first loop device 15 has a pressure difference between the outlet and the inlet). Therefore, the first loop device 15 is also a self-evaporating device, and due to the pressure difference, self-evaporation occurs, and the first liquid phase is mixed with the first self-evaporating gas phase and the first self-evaporating gas phase during the self-evaporation process. The first self-evaporating gas phase flows upward into the second mist eliminator 22, through which it enters the second steam passage 23, and then into the third effect evaporator unit 3; the first concentrated liquid phase flows downward into the second heat exchange chamber 21, where the first concentrated liquid phase and the first gas phase exchange heat for the second time (the temperature of the first gas phase is higher than that of the first concentrated liquid phase), and the first concentrated phase is again separated into a gas phase and a liquid phase, i.e., a second gas phase and a second liquid phase; the second gas phase flows upward through the second mist eliminator 22, through which it enters the second steam passage 23, and then into the third effect evaporator unit 3, where it exchanges heat as a heat source; and the second liquid phase flows through the second downcomer 24 into the second loop device 25 to achieve self-evaporation.

[0037] During the purification process of the second effect evaporative unit 2, the first gas phase enters the pipes in the second heat exchange chamber 21 through the first steam passage 13, and after a second heat exchange in the second heat exchange chamber 21, the first gas phase is cooled to the first condensate, which flows downward from the first condensate passage 26. In the process of flowing downward, the condensate first collects sufficiently in the first U-shaped tube 27 at the bottom of the first condensate passage 26, which acts as a partition between the second effect evaporative unit 2 and the third effect evaporative unit, causing a pressure difference between the two.

[0038] The second effect evaporation unit 2 can perform a second heat exchange without an external heat source, and the heat source for the second heat exchange is provided by the first gas phase from the first evaporation unit, and the heat source flows from the first gas phase to the first concentrated liquid phase.

[0039] The temperature of the second effect evaporating unit 2 is about 80° C. (75 to 90° C.), and the pressure of the second effect evaporating unit 2 is about 0.038 to 0.07 MPa.

[0040] Similarly, the third effect evaporation unit 3 includes a third heat exchange chamber 31, a third vapor phase outlet and a third liquid phase outlet are provided above the third heat exchange chamber 31, a third mist eliminator 32 is provided above the third vapor phase outlet, the third mist eliminator 32 communicates with a third vapor passage 33 (preferably located in the tower), the third liquid phase outlet communicates with a third downcomer 34, a third loop device 35 is provided at the bottom of the third downcomer 34, and a third effect evaporation unit 35 is provided at the bottom of the third heat exchange chamber 31. A second condensate passage 36 is connected to the upper part of the heat exchange chamber of the member, the end of the second steam passage 23 is connected to the third heat exchange chamber 31, the outlet of the second loop device 25 is located above the third heat exchange chamber 31 and below the third mist eliminator 32, a second U-shaped tube 37 is provided at the bottom of the second condensate passage 36, and the condensate remaining in the second U-shaped tube 27 acts to separate the second effect evaporating unit 2 and the third effect evaporating unit 3, and at the same time creates a pressure difference between them. Similarly, a second U-shaped tube 37 is provided at the bottom of the second condensate passage 36, and the function of the second U-shaped tube 37 is the same as that of the first U-shaped tube 27.

[0041] The principle of separation of the gas phase and the liquid phase in the third effect evaporation unit 3 is the same as that of the second effect evaporation unit 2, the third effect evaporation unit 3 can perform a third heat exchange without an external heat source, and the direction of heat exchange is the same as that of the second effect evaporation unit 2.

[0042] The temperature of the third effect evaporative unit 3 is about 60° C. (55 to 80° C.), and the pressure of the third effect evaporative unit 3 is about 0.02 to 0.047 MPa.

[0043] Similar to the third effect evaporative unit 3, the fourth effect evaporative unit 4 includes a fourth heat exchange chamber 41, a fourth gas phase outlet and a concentrated water outlet are provided above the fourth heat exchange chamber 41, a fourth mist eliminator 42 is provided above the fourth gas phase outlet, the fourth mist eliminator 42 is connected to a fourth steam passage 43, and the concentrated water remaining due to continuous evaporation can be discharged from the concentrated water outlet 6, a third condensate passage 46 leading to the last effect condensing unit 5 is connected to the bottom of the fourth heat exchange chamber 41, and a third U-shaped tube 47 is provided at the bottom of the third condensate passage 46, and the function of the third U-shaped tube 47 is the same as that of the U-shaped tube of the previous effect member.

[0044] The temperature of the fourth effect evaporative unit 4 is about 45° C. (40 to 70° C.), and the pressure of the fourth effect evaporative unit 4 is about 0.003 to 0.07 MPa.

[0045] During the purification process, the vacuum pump 7 located at the bottom of the tower is constantly operating to adjust the pressure of each effect evaporation unit. From bottom to top, the pressure inside the tower gradually decreases, and from top to bottom, the vacuum degree gradually increases. At the same time, due to the partitioning action of the U-shaped tube and the loop-shaped device, there is a pressure difference between each effect evaporation unit, and the evaporation speed is also increased by this pressure difference. At the same time, the present invention also utilizes the effect of gravity, and the entire purification process proceeds gradually from top to bottom.

[0046] During the purification process, H2O continues to evaporate and enters the next effect member through the steam passage, and at the same time, the liquid phase carries heat to exchange with the next effect evaporator unit, and some of the condensed H2O finally flows into the last effect condenser unit 5 through the condensate passage, while the uncondensed part enters the next effect evaporator unit and continues to exchange heat, so that it enters the last effect condenser unit 5 through the fourth steam passage 43 and can be condensed into purified water and discharged, and the concentrated water evaporated several times is discharged from the concentrated water outlet for further treatment. In order to exchange heat with the purified water vapor and cool it, the last effect condenser unit 5 is provided with a cooling water inlet 05 and a cooling water outlet 06, and the cooling water inlet 05 is located at the bottom of the last effect condenser unit 5, and the cooling water outlet 06 is located at the top of the last effect condenser unit 5.

[0047] A purified water reservoir 8 is provided at the bottom of the tower, and a purified water outlet 81 is provided at the bottom of the purified water reservoir 8.

[0048] The configuration of the fourth-effect evaporation unit provided by the above embodiment can be any solution of 2, 3, 4, 5, etc. multiple effects in actual operation.

Claims

1. A separation tower for treating condensate, comprising a tower body, an evaporation unit having a plurality of effect evaporation units for purifying the condensate is provided within the tower body, a final effect condensing unit into which cooling water is introduced from the outside is provided below the evaporation unit, and a vacuum pump capable of gradually reducing pressure from top to bottom within the tower body and generating a pressure difference among the plurality of effect evaporation units is connected to the final effect condensing unit, The evaporation unit includes, as the plurality of effect evaporation units, N (N≧3) effect evaporation units arranged in the tower body in the order of a first effect evaporation unit, a second effect evaporation unit, ..., an Nth effect evaporation unit, The uppermost first effect evaporator unit among the plurality of effect evaporators includes a heat exchange chamber for performing heat exchange between the condensate introduced from the outside and steam introduced from the outside, The heat exchange chamber includes a condensate inlet for introducing the condensate from the outside below the heat exchange chamber, a steam inlet for introducing the steam as a heat source for the heat exchange into a heat exchange pipe in the heat exchange chamber, and a mist eliminator provided above the heat exchange chamber, and the condensate inlet is provided above the heat exchange chamber. a vapor passage through which a vapor phase produced by vaporizing a portion of the condensate through heat exchange in the heat exchange chamber enters a second effect evaporating unit among the plurality of effect evaporating units; and a downcomer extending to the second effect evaporating unit and through which a liquid phase of the condensate after the heat exchange passes and flows to the second effect evaporating unit; Each of the second effect evaporation unit to the N-1st effect evaporation unit among the plurality of effect evaporation units includes a heat exchange chamber and a mist eliminator provided above the heat exchange chamber, and a vapor passage and a downcomer are connected above the heat exchange chamber. The vapor passage is provided so that a part of the liquid phase flowing in through the downcomer connected to the effect evaporation unit one level above is vaporized by heat exchange in the heat exchange chamber, and the vapor phase generated by the vaporization enters the heat exchange chamber included in the effect evaporation unit one level below as a heat source for heat exchange. The downcomer extends to the effect evaporation unit one level below. a pipe is provided for the liquid phase after the heat exchange of the liquid phase flowing in through the downcomer connected to the one upper effect evaporating unit to flow to the one lower effect evaporating unit, a loop-shaped device is provided at the bottom of the downcomer extending from the one upper effect evaporating unit to allow a part of the liquid phase after the heat exchange to self-evaporate, a condensate passage is connected to the bottom of the heat exchange chamber through the steam passage connected to the one upper effect evaporating unit and for condensate generated after heat exchange to flow to the one lower effect evaporating unit, and a U-shaped pipe is provided at the bottom of the condensate passage, The lowest N-th effect evaporating unit among the plurality of effect evaporating units includes a heat exchange chamber and a mist eliminator provided above the heat exchange chamber, and a vapor passage is connected above the heat exchange chamber, and the vapor passage is provided for a vapor phase generated by vaporizing a part of a liquid phase flowing in through the downcomer connected to the effect evaporating unit one level above by heat exchange in the heat exchange chamber and entering the last effect condensing unit, and further, a loop-shaped device is provided at the bottom of the downcomer extending from the effect evaporating unit one level above, and further, the vapor phase is introduced into the heat exchange chamber through the vapor passage connected to the effect evaporating unit one level above, a condensate passage through which the condensate produced after the heat exchange flows to the last effect condensing unit is connected to the bottom of the heat exchange chamber, and a U-shaped tube is provided at the bottom of the condensate passage; In each of the second effect evaporation unit to the Nth effect evaporation unit among the plurality of effect evaporation units, each of the loop devices is located between each of the heat exchange chambers and each of the mist eliminators, The final effect condensation unit to which the cooling water is introduced cools and condenses the gas phase and the condensate flowing in from the Nth effect evaporation unit to generate purified water. A separation column characterized by:

2. A purified water storage area for storing the purified water is further provided below the final effect condensing unit.

2. The separation column according to claim 1 .

3. The evaporation unit includes a third effect evaporation unit disposed below the second effect evaporation unit.

2. The separation column according to claim 1 .

4. The evaporation unit includes a fourth effect evaporation unit as the Nth effect evaporation unit below the third effect evaporation unit. The separation column according to claim 3 .

5. In each of the plurality of effect evaporation units, the mist eliminators are provided between the heat exchange chambers and the steam passages in the vertical direction.

2. The separation column according to claim 1 .

6. A method for treating condensate using the separation column according to claim 5, comprising: 1) opening the vacuum pump, injecting the condensate into the first effect evaporative unit through the condensate inlet, and introducing steam as a heat source into the heat exchange line in the heat exchange chamber included in the first effect evaporative unit; 2) the condensate and the steam exchange heat in the heat exchange chamber of the first effect evaporator unit, and the condensate is separated into a first gas phase and a first liquid phase, the first gas phase passes through the mist eliminator included in the first effect evaporator unit and then enters the steam passage connected to the first effect evaporator unit, and enters the second effect evaporator unit through the steam passage, and the first liquid phase flows to the second effect evaporator unit through the downcomer connected to the first effect evaporator unit; 3) A step performed in each of the second effect evaporation unit to the N-1 effect evaporation unit, in which an M-1 liquid phase generated in an M-1 effect evaporation unit (M-1 effect evaporation unit) one effect above an M-1 effect evaporation unit (M is 2 to N-1) and flowing to the M-1 effect evaporation unit through the downcomer connected to the M-1 effect evaporation unit is partially self-evaporated in the loop device provided at the bottom of the downcomer to become an M-1 concentrated liquid, and an M-1 gas phase generated in the M-1 effect evaporation unit and entering the heat exchange pipe in the heat exchange chamber of the M-1 effect evaporation unit through the vapor passage connected to the M-1 effect evaporation unit is heat-exchanged with the M-1 concentrated liquid in the heat exchange chamber as a heat source for the M-th heat exchange, and condensed by the M-th heat exchange. the M-1 concentrated liquid flows downward from the condensate passage connected to the bottom of the heat exchange chamber and enters a U-shaped tube provided at the bottom of the condensate passage; the M-1 concentrated liquid flows out of the outlet of the loop device of the downcomer connected to the M-1 effect evaporation unit, and undergoes the Mth heat exchange with the M-1 gas phase in the heat exchange chamber of the M effect evaporation unit located below the outlet, whereby a part of the M concentrated liquid is evaporated into an M gas phase and the remaining part into an M liquid phase; the M gas phase flows upward through the mist eliminator of the M effect evaporation unit and enters the steam passage connected to the M effect evaporation unit, and then enters the M+1 effect evaporation unit one effect below the M effect evaporation unit; and the M liquid phase flows to the M+1 effect evaporation unit via the downcomer connected to the M effect evaporation unit; 4) A step performed in the Nth effect evaporation unit after step 3, in which an N-1st liquid phase generated in an effect evaporation unit (N-1st effect evaporation unit) one level above the Nth effect evaporation unit and flowing to the Nth effect evaporation unit through the downcomer connected to the N-1st effect evaporation unit is partially self-evaporated in the loop device provided at the bottom of the downcomer to become an N-1st concentrated liquid, and the N-1st concentrated liquid flows out from the outlet of the loop device toward the heat exchange chamber of the Nth effect evaporation unit located below the outlet, and an N-1st gas phase generated in the N-1st effect evaporation unit and entering the heat exchange pipe in the heat exchange chamber of the Nth effect evaporation unit through the vapor passage connected to the N-1st effect evaporation unit is evaporated in the heat exchange chamber. the N-1st condensate flows downward from the condensate passage connected to the bottom of the heat exchange chamber and enters a U-shaped tube provided at the bottom of the condensate passage; the N-1st condensate exchanges with the N-1st gas phase in the heat exchange chamber for the Nth time, so that a portion of the N-1st condensate evaporates to become an Nth gas phase and the remaining portion becomes an Nth liquid phase; the Nth gas phase flows upward through the mist eliminator of the Nth effect evaporator unit and enters the steam passage connected to the Nth effect evaporator unit, and then enters the final effect condensing unit; and the Nth liquid phase remains in the heat exchange chamber as concentrated water that can be discharged from a concentrated water outlet provided in the heat exchange chamber; 5) Finally, the Nth gas phase enters the final effect condensation unit to be condensed, mixed with the condensate generated by the Nth heat exchange, and becomes purified water, which can be discharged; the concentrated water is discharged from the concentrated water outlet for further processing; and finally, the purified water is separated from other substances. A method comprising:

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