KR20210067867A - Apparatus and method for separating different substances - Google Patents

Abstract

Provided are an apparatus and a method for separating different substances to facilitate energy saving. In the apparatus for separating different substances (ammonia recovery apparatus (1)) in which a first vapor (ammonia-containing vapor) is generated from a stock solution (ammonia-containing wastewater) and introduced into an evaporator (3), the first vapor is condensed and concentrated by heat-exchanging with liquid (water), the liquid is evaporated and discharged as a second vapor (water vapor), and the second vapor is heated by a temperature raising means (compression device (18)) so as to be used to generate the first vapor serving as heating vapor, the evaporator (3), that is, at least two split evaporators (upstream and downstream evaporators (3A, 3B)) is is connected in series along the flow direction of the first vapor, each of the two split evaporators is provided with heating means (upstream side and downstream side steam compressors (18A and 18B)), and a temperature difference by the upstream side temperature increasing means for increasing the temperature of the second vapor is smaller than the downstream side temperature increasing means.

Description

Separation apparatus and method for dissimilar substances {APPARATUS AND METHOD FOR SEPARATING DIFFERENT SUBSTANCES}

The present invention separates heterogeneous substances such as the low-boiling-point substances from, for example, a stock solution containing two or more substances, such as wastewater containing low-boiling-point substances such as ammonia. It relates to a separation device and a separation method.

For example, as a method for separating and removing ammonia-containing wastewater, a steam stripping method is known. In a general ammonia recovery apparatus using this steam stripping method, a distillation column for performing steam stripping is provided, the ammonia-containing vapor discharged from the column top of the distillation column is condensed by a condenser, and the condensed water is refluxed. It is returned to the top of the distillation column as a liquid, and the remaining concentrated ammonia-containing vapor is supplied to the absorption tower, absorbed in water, and taken out as recovered ammonia water.

By the way, the steam stripping method used for such an ammonia recovery apparatus is a method of directly blowing water vapor into the bottom of a distillation column, and since a large amount of water vapor is used, running cost is high and reduction of processing cost is calculated|required. On the other hand, in this method, ammonia-containing steam is generated in an amount substantially equal to that of the injected steam. In order to use this as a reflux liquid and a recovered ammonia solution to the top of the distillation column, a heat exchanger (condenser) installed at the top of the column It needs to be cooled by the , and energy is consumed and wasted.

In order to solve such a problem, it has been proposed to compress the vapor discharged from the top of the distillation column by a vapor compressor and to recover heat by using a reboiler to reduce the amount of water vapor (see Patent Document 1 below). In addition, make-up water is supplied to a condenser that splits ammonia-containing vapor discharged from the top of the distillation column, heat exchanges with ammonia-containing vapor to evaporate the make-up water, and guides to a vapor compressor to compress and increase the temperature to steam A configuration for reuse as a suffix has been proposed (see Patent Document 2 below).

Patent Document 1: Japanese Patent Laid-Open No. 2002-28637 Patent Document 2: Japanese Patent Laid-Open No. 2004-114029

In the prior art disclosed in Patent Documents 1 and 2, the heat of the ammonia-containing vapor discharged from the top of the distillation column is effectively used, energy saving is achieved, and the running cost is reduced.

However, in the configuration of the prior art including at least a distillation column, a heat exchanger (reboiler or condenser: these reboiler or condenser are equivalent to the evaporator of the present application), and a vapor compressor, for example, in order to recover high concentration ammonia of 20 wt% or more Then, the following problems arise. That is, if the temperature difference between the inlet and outlet of the ammonia-containing vapor in the heat exchanger is increased to a high concentration only by the heat exchanger (corresponding to the evaporator of the present application), the load on the vapor compressor becomes too large by that amount. It goes against the request for energy saving by the use of Moreover, the said subject is not limited to ammonia, but it is common to the collection|recovery apparatus containing a low boiling point substance widely.

Then, conventionally, the low-boiling-point substance recovery|recovery apparatus in which energy saving was achieved has been desired.

This invention was conceived in view of the said subject, and the objective is to provide the separation apparatus and separation method of the dissimilar substance by which energy saving was achieved effectively.

In order to achieve the above object, the invention according to claim 1 generates a first vapor from an undiluted solution composed of two or more substances and introduces it to the evaporator, and heat exchanges the first vapor with the liquid. By making the first vapor condensed and concentrated, the liquid is evaporated and discharged as a second vapor, and the second vapor is heated by a temperature increasing means to form the second vapor as a heating vapor. A separation apparatus for dissimilar substances used for generating one vapor, wherein the evaporator has a configuration in which at least two split evaporators are connected in series along a flow direction of the first vapor, and the temperature rises in the two split evaporators, respectively means is provided, and among the two split evaporators, the temperature increasing means provided in the upstream split evaporator in the flow direction of the first vapor is higher than the temperature increasing means provided in the downstream split evaporator. 2 It is characterized in that the temperature difference when the steam is heated is small.

According to the above configuration, since the temperature difference between the upstream side of the temperature increasing means when raising the second steam is smaller than that of the downstream side of the temperature increasing means, the load on the upstream side of the temperature increasing means is reduced, thereby reducing the temperature of the device. Energy saving can be achieved. In addition, since the second steam heated by the upstream temperature raising means becomes relatively high temperature, its specific volume becomes small, so that the upstream temperature raising means can be made small by that amount. have.

The invention according to claim 2 is the apparatus for separating dissimilar substances according to claim 1, wherein the two split evaporation units are formed by dividing one evaporator.

Further, in the present invention, the terms "(split) evaporator" to "evaporator" can also be rewritten as, for example, "(divided) heat exchange part" to "heat exchanger".

Although it is also possible to set it as the structure using two evaporators as two split evaporators, for example, according to the structure which divides one evaporator as mentioned above, compactization of an apparatus and reduction of cost can be aimed at.

The invention according to claims 3 and 4 is an apparatus for separating heterogeneous substances according to claims 1 or 2, a means for generating the first vapor from the stock solution, contacting the stock solution with steam for heating, and removing the stock solution from the stock solution. Separating and gasifying one or more heterogeneous substances, and discharging from the top of the tower as the first vapor containing the one or more heterogeneous substances, and discharging the treatment liquid from which the one or more heterogeneous substances are removed from the undiluted solution to the bottom of the column It is characterized in that it is provided with a distillation column for storing (貯留).

According to the said structure, the 1st vapor|steam can be produced|generated preferably by the steam stripping method which is excellent in points, such as compactization of an apparatus and stability of a process.

The invention according to claim 5 is an apparatus for separating different substances according to any one of claims 1 to 4, wherein the temperature increasing means provided in the upstream split evaporator includes the temperature increase means provided in the downstream split evaporator. It is characterized in that it is smaller.

According to the above configuration, the device can be further energy-saving or compact.

In addition, that one temperature raising means is smaller than the other among two temperature raising means means that one temperature raising means is smaller in power consumption and/or size than the other. Further, for example, by preparing three or more temperature raising means, dividing them into two groups, and configuring one group with fewer temperature raising means than the other group, it is possible to constitute a smaller temperature raising means than the other. can

The invention according to claim 6 is an apparatus for separating heterogeneous substances according to any one of claims 1 to 4, wherein the undiluted solution contains water and a low boiling point substance (in other words, the two or more substances are at least water and containing low-boiling-point substances).

As the "low boiling point substance", for example, a substance having a lower boiling point than water can be applied, and more specifically, alcohols such as ammonia and methanol, ketones such as acetone, esters such as methyl acetate, etc. can be applied. have.

As "water", pure water, soft water, ion-exchanged water, etc. are applicable.

The invention according to claim 7 is the apparatus for separating dissimilar substances according to any one of claims 1 to 4, wherein the temperature increasing means includes a heat pump and/or a steam ejector.

As a "heat pump", vapor compressors, such as a root-type vapor compressor, a turbo-type vapor compressor, a screw-type vapor compressor, and a vane-type vapor compressor, are mentioned, for example.

In the invention of claim 8, a stock solution containing a low-boiling point substance is brought into contact with steam for heating, the low-boiling point substance is separated from the stock solution and gasified, and the low-boiling point substance is discharged from the top of the tower as a vapor containing the low boiling point substance, and the low-boiling point substance from the stock solution By exchanging water with a distillation column storing the removed treated water at the bottom of the column, and water discharged from the top of the distillation column, the vapor containing the low-boiling-point substance is condensed to condense the low-boiling-point substance. Concentrate the vapor containing the, and further, an evaporation unit for evaporating the water and discharging it as water vapor, and compressing and raising the temperature of the water vapor discharged from the evaporation unit, and guide the compressed and heated water vapor to the distillation column, and used in the distillation column A separation device for dissimilar substances having a compression device used as steam for heating to be used, wherein the evaporator has a configuration in which at least two split evaporators are connected in series along a flow direction of the vapor containing the low-boiling-point substance; The compression device is provided in each of the split evaporators, and the compression device provided in the split evaporator on the upstream side in the flow direction of the vapor containing the low-boiling point substance among the two split evaporators is divided on the downstream side. It is characterized in that the temperature difference at the time of compressing and raising the temperature of the steam is smaller than that of the compression device provided in the evaporator.

According to the above configuration, since the temperature difference when the upstream compression device compresses and heats up water vapor is smaller than that of the downstream compression device, the load applied to the upstream compression device becomes small, thereby reducing the energy of the device. savings can be achieved. Moreover, since the water vapor|steam compressed and heated by the said upstream compression device becomes relatively high temperature, the specific volume becomes small, Therefore, the said upstream compression device can be made small by that much.

In the invention according to claim 9, the first vapor is condensed and concentrated by generating a first vapor from an undiluted solution containing two or more substances, introducing it to the evaporator, and exchanging the first vapor with a liquid to heat exchange. In addition, as a separation method of dissimilar substances used for generating the first vapor as a vapor for heating by evaporating the liquid and discharging it as a second vapor, and raising the temperature of the second vapor by a temperature increasing means, the evaporator , at least two split evaporators are connected in series along the flow direction of the first vapor, the two split evaporators are respectively provided with the temperature raising means, and among the two split evaporators, the first It is characterized in that the temperature difference between the temperature increase means provided in the split evaporation section on the upstream side in the steam flow direction is smaller than the temperature increase means provided in the split evaporation section on the downstream side when raising the temperature of the second steam. .

According to the said structure, the separation method of the dissimilar substance in which energy saving was achieved effectively is built.

ADVANTAGE OF THE INVENTION According to this invention, when isolate|separating heterogeneous substances, such as ammonia, from undiluted|stock solutions, such as ammonia containing wastewater, energy saving can be achieved effectively.

BRIEF DESCRIPTION OF THE DRAWINGS It is the overall block diagram of the ammonia recovery apparatus which concerns on embodiment.
FIG. 2 is an enlarged view of the vicinity of the evaporator in the ammonia recovery apparatus of FIG. 1 .
3 is an enlarged view of the vicinity of the concentration tower in the ammonia recovery apparatus of FIG.
4 is a graph showing the gas-liquid equilibrium diagram at atmospheric pressure of a mixture consisting of water and ammonia, in which the ammonia concentration is 0 to 100%.
5 is a gas-liquid equilibrium diagram of a mixture consisting of water and ammonia at atmospheric pressure, and is a graph showing ammonia concentrations of 0-50%.
6 is an enlarged view of a modified example for comparison and comparison, in which the evaporator is configured as a single evaporator.
Fig. 7 is an enlarged view of a modified example formed by dividing a plurality of divided evaporators by one evaporator.
8 is a plan view of the evaporator of FIG. 7 .
9 is an enlarged view of a modified example in which a steam ejector is used as a temperature increase means.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is described in detail based on embodiment. In the following embodiments, an ammonia recovery device that uses ammonia-containing wastewater as a stock solution and separates and removes ammonia from the ammonia-containing wastewater to recover the heterogeneous substance separation device will be exemplified and described. As a heterogeneous substance, it can apply also to alcohols, such as methanol, ketones, such as acetone, and ester, such as methyl acetate, besides ammonia.

(embodiment)

BRIEF DESCRIPTION OF THE DRAWINGS It is an overall block diagram of the ammonia recovery apparatus which concerns on embodiment. The ammonia recovery device (corresponding to the heterogeneous substance separation device of the present invention) 1 comprises a distillation column 2 in which steam for heating is blown to perform steam stripping, and ammonia-containing steam discharged from the top of the distillation column 2 and An evaporator (3) for evaporating water by exchanging water with water, a compression device (18) for compressing and increasing the temperature of the steam discharged from the evaporator (3) and discharging it to the distillation column (2) as steam for heating, and an evaporator (3) ), the concentration of the ammonia-containing vapor is added to the vapor, and the vapor is cooled to remove moisture to increase the concentration of the ammonia-containing vapor to a high concentration (for example, 20 wt% or more), and A first absorption tower (6) for absorbing moisture in ammonia-containing vapor to generate recovered ammonia water having a predetermined concentration, and a second absorption tower (7) for preventing non-condensed ammonia-containing vapor in the first absorption tower from being discharged to the outside. ) is provided. Here, when an outline of the characteristics of the ammonia recovery device 1 according to the present embodiment is described, the evaporator 3 uses two evaporators 3A and 3B as two split evaporators to determine the flow direction of the ammonia-containing vapor. Therefore, it has a configuration connected in series, and vapor compressors 18A and 18B serving as temperature increase means are respectively provided in these two evaporators 3A and 3B, and among the two evaporators 3A and 3B, the flow direction of ammonia-containing vapor The temperature difference between the vapor compressor 18A provided in the evaporator 3A on the upstream side in the evaporator 3A is smaller than that of the vapor compressor 18B provided in the evaporator 3B on the downstream side when the steam is compressed and heated.

Hereinafter, the specific structure of the ammonia recovery apparatus 1 is demonstrated including the said characteristic structure.

For the distillation column 2, a multi-stage thing may be used, and it is not limited to this, You may use the thing which is not a multi-stage thing. That is, for the distillation column 2, a bed column or a packed column can be used. A stock solution (ammonia-containing wastewater) is supplied to the top of the distillation column 2 through a stock solution supply pipe L1. Moreover, you may make it pH-adjust the undiluted|stock solution beforehand.

To the bottom of the distillation column 2 , the steam for heating from the steam ejector 10 is supplied through the steam supply pipe L3 for heating. The column bottom of the distillation column 2 is connected to the heat recovery tank 11 through a tube L4, and the storage liquid (low concentration ammonia water) at the bottom of the column is supplied to the heat recovery tank 11 through the tube L4. it is made to be The steam ejector 10 is a steam compression means for suctioning and compressing steam, and to the steam suction side 10a, a steam supply pipe L5 through which steam supplied from a high-pressure steam source (not shown) such as a boiler flows. and a vapor reuse pipe L6 extending from the heat recovery tank 11 is connected. With this configuration, the stored liquid in the heat recovery tank 11 is flash evaporated, sucked and compressed by the steam ejector 10, mixed with the steam from the steam supply pipe L5, and is used as a heating steam in the distillation column. It is blown into the bottom of the tower of (2). In this way, the stored liquid in the heat recovery tank 11 is flash evaporated, reused as a part of the heating steam, and heat is recovered.

Further, at the bottom of the heat recovery tank 11, a discharge pipe L7 for discharging treated water (for example, low-concentration ammonia water of 30 ppm or less) is connected, and on this discharge pipe L7, a pump for discharging treated water ( P1), and three heat exchangers H1, H2, H3 are provided. Heat exchanger H1 is a water heater which heat-exchanges water and treated water, and heats water. The water heated by the heat exchanger H1 is supplied to the bottoms of the evaporators 3A and 3B through the water supply pipe L8. The heat exchanger H2 is a stock solution preheater that heats the stock solution and treated water and heats the stock solution in advance. The stock solution preheated by the heat exchanger H2 is supplied to the top of the distillation column 2 through the stock solution supply pipe L1. The heat exchanger H3 is a cooler that heats the cooling water and the treated water and cools the treated water. The treated water cooled by this heat exchanger H3 is discharged out of the system through the discharge pipe L7.

The heat exchangers H1, H2, and H3 are located on the discharge pipe L7 on the downstream side of the pump P1 for discharging the treated water, and are provided in the following order. That is, on the discharge pipe L7, the heat exchanger H1 is provided on the upstream side of the heat exchanger H2. By providing in this order, since the amount of heat given to the water from the treated water is the largest, energy saving is achieved in the evaporator 3 that heats the water. In addition, since the reason for providing the heat exchanger H3 is to cool the treated water, the heat exchanger H3 is provided on the downstream side of the heat exchangers H1 and H2.

The evaporator 3 connects the two evaporators 3A and 3B in series in this order along the flow direction of the ammonia-containing vapor between the top of the distillation column 2 and the top of the concentration column 5 . It is connected and comprised, and these evaporators 3A and 3B are comprised with horizontal tube type evaporation can 12A and 12B, respectively, and are provided with spreaders 13A and 13B and indirect heaters 14A and 14B. Moreover, it is not limited to a horizontal tube type, For example, you may use evaporation cans, such as a thin-film flow-down (long-tube) type. Among the two evaporators 3A and 3B, in the distribution direction of the overhead vapor (ammonia-containing vapor) discharged from the top of the distillation column 2 and supplied to the evaporator 3 through a vapor supply pipe L10 to be described later. In the evaporator (hereinafter also referred to as "upstream evaporator") 3A disposed on the upstream side of the indirect heater 14A, as shown in FIG. 2 , a heat transfer tube group 15A composed of one or a plurality of horizontal heat transfer tubes. ) and a pair of headers 16R and 16L on upstream and downstream sides (right and left in the drawing). Further, the bottom of the evaporation can 12A is a storage portion 17A that stores water supplied through the pipe L8. The storage liquid (water) of the storage part 17A is supplied to the spreader 13A provided in the upper part in the evaporation can 12A through the pipe L9A by the circulation pump P2A, and from this spreader 13A After spraying toward the outer surface of the heat transfer tube group 15A, it is comprised so that it may circulate that it flows into the storage part 17A of the lower part in the evaporation can 12A.

On the other hand, among the two evaporators 3A and 3B, an indirect heater 14B, storage in an evaporator (hereinafter also referred to as a "downstream evaporator") 3B disposed on the downstream side in the flow direction of the overhead vapor Since the structures of the part 17B, the circulation pump P2B, the pipe L9B, and the spreader 13B are all the same as the case of the said upstream evaporator 3A, description is abbreviate|omitted.

The header 16R on the upstream side of the upstream evaporator 3A is connected to the top of the distillation column 2 through a vapor supply pipe L10, and the top vapor (containing ammonia) discharged from the top of the distillation column 2 . steam) is guided to the header 16R on the upstream side via the steam supply pipe L10, and further circulates in the heat transfer pipe group 15A. Here, the upstream evaporator 3A has a pressure lower than the pressure of the overhead vapor, so the circulating liquid (water) sprayed by the spreader 13A evaporates as a thin film on the surface of the heat transfer tube group 15A, water vapor is generated. This water vapor is supplied to 18A of vapor compressors (hereinafter also referred to as "upstream vapor compressors") provided in the upstream evaporator 3A in the compression device 18 . Here, the principle of vaporizing water in the upstream evaporator 3A will be described in more detail. In the upstream evaporator 3A, the pressure outside the heat transfer tube with water to be heated rather than the overhead steam (inside the heat transfer tube) serving as a heating source. Because it is low, water evaporates. Further, the pressure difference is generated by the compression device 18 (specifically, the upstream steam compressor 18A). This is because the outside of the evaporator heat transfer tube connected to the suction side of the compression device 18 is low, and the pressure of the overhead vapor advancing in the distillation column 2 connected to the discharge side of the compression device 18 is high. In addition, the pressure in the distillation column 2 is also increased by the steam supplied from the steam ejector 10, which is a factor in which water in the upstream evaporator 3A is evaporated.

Further, condensed water (low-concentration ammonia water) condensed by flowing through the heat transfer tube group 15A is stored in the downstream header 16L. The downstream header 16L is connected to the header on the upstream side in the downstream evaporator 3B, and the condensed water (low concentration ammonia water) stored in the header 16L on the downstream side in the upstream evaporator 3A is , through the pipe L19, from the downstream header in the downstream evaporator 3B by driving the condensate pump P3, and returned to the top of the distillation column 2 as a reflux liquid through the pipe L11 lose The remaining surplus vapor (concentrated ammonia-containing vapor) is discharged from the downstream header in the downstream evaporator 3B to the top of the enrichment tower 5 through the pipe L12.

In addition to the upstream steam compressor 18A, the compression device 18 is also provided with a steam compressor (hereinafter also referred to as a "downstream steam compressor") 18B provided in the downstream evaporator 3B, and these upstream The side and downstream steam compressors 18A and 18B connect the bottom of the distillation column 2 and the top of the upstream evaporator 3A and the downstream evaporator 3B, respectively. That is, the inlet side of the upstream side vapor compressor 18A is connected to the upper part of the evaporation can 12A in the upstream side evaporator 3A through the pipe L15, and the outlet side of the upstream side vapor compressor 18A is connected with the pipe L16. ) connected to the bottom of the distillation column 2 . The inlet side of the downstream steam compressor 18B is connected to the upper part of the evaporation can 12B in the downstream evaporator 3B via a pipe L17, and the outlet side of the downstream steam compressor 18B connects a pipe L18. It is connected to the bottom of the distillation column 2 via the distillation column 2 .

Here, as the upstream side and downstream side steam compressors 18A and 18B, a route type steam compressor with a large maximum differential pressure is used. However, in the present invention, the present invention is not limited to the root type steam compressor, and any one of a turbo type steam compressor, a screw type steam compressor, a vane type steam compressor, or other steam compressors may be used. In addition, in this embodiment, although the compression apparatus 18 was comprised by each one and two steam compressors 18A and 18B on an upstream side and a downstream side, at least two units|units on at least one of an upstream side and a downstream side, a total It may consist of three or more vapor compressors.

As shown in FIG. 1, the concentration tower 5 is comprised by the spray type scrubber. The storage liquid (condensate) stored at the bottom of the concentration tower 5 flows through a spray pipe (corresponding to the circulation line of the present invention) L20, is guided to the top of the tower, and is sprayed toward the inside of the top of the tower. . A circulation pump P4 and a heat exchanger H4 are provided in the middle of this spray pipe L20. The storage liquid flowing through the spray pipe L20 is heat-exchanged with the cooling water in the heat exchanger H4 and cooled. Moreover, as shown in FIG. 3, the control valve V1 is provided in the pipe L21 through which the cooling water flows, and it is connected to the temperature sensor T which detects the temperature of the storage liquid stored in the tower bottom of the concentration tower 5. The opening is controlled by That is, the opening degree of the control valve V1 is controlled according to the detection result of the temperature sensor T, and the flow rate of the cooling water passing through the heat exchanger H4 is adjusted. Thereby, the ammonia-containing vapor of a predetermined high concentration (for example, 20 wt% or more) can be produced|generated by cooling and spraying a storage liquid (condensate liquid) to predetermined temperature.

The spray pipe L20 is branched on the way, and the branch pipe L22 is connected to the top of the distillation column 2 . A control valve V2 is provided in the middle of the branch pipe L22. Moreover, in the concentration tower 5, the liquid level sensor S1 which detects the liquid level of a storage liquid is provided. Liquid level sensor S1 has level switch S1a which detects an upper limit set level, and level switch S1b which detects a lower limit set level. By this liquid level sensor S1, the opening degree of the control valve V2 is controlled so that the storage liquid is maintained at a predetermined liquid level, and the stored liquid overflowing the predetermined liquid level is refluxed to the top of the distillation column 2 has been

1, the 1st absorption tower 6 is comprised by the same spray type scrubber as the concentration tower 5, and the spray pipe L23 through which the storage liquid of the 1st absorption tower 6 circulates. A circulation pump P5 and a heat exchanger H5 are provided. In the heat exchanger H5, the storage liquid which flows through the spray pipe L23 and cooling water heat-exchange, and the storage liquid is cooled. The cooled storage liquid is sprayed with ammonia-containing vapor of high concentration (for example, 20 wt% or more) taken in from the concentration tower 5 through the pipe L24, thereby condensing and recovering the ammonia-containing vapor to produce recovered ammonia water. do. In addition, the spray pipe L23 is branched on the way, and the recovered ammonia water is discharged out of the system through the branch pipe L25.

The second absorption tower 7 is composed of the same spray type scrubber as the first absorption tower 6, and water is supplied to the bottom of the second absorption tower 7 through a pipe L30, Water stored in the bottom is sprayed from the top of the tower through the spray pipe L31 by driving the circulation pump P6. Between the first absorption tower (6) and the second absorption tower (7), a pipe (L32) for guiding the uncondensed ammonia-containing vapor in the first absorption tower (6) to the top of the second absorption tower (7) ) and a pipe L33 for returning the condensed water in the second absorption tower 7 to the first absorption tower 6 are provided. Further, an exhaust pipe L34 for exhausting the vapor from which ammonia has been removed is provided at the top of the second absorption tower 7 .

In addition, in FIGS. 1 to 3 , L40 is a cooling water supply pipe, L41 is a pipe branching from the cooling water supply pipe L40, L21 is a pipe branching from the cooling water supply pipe L40, and a heat exchanger H5 is provided on the cooling water supply pipe L40. is provided, the heat exchanger H3 is provided on the tube L41, and the heat exchanger H4 is provided on the tube L21.

Next, the processing operation of the ammonia recovery device 1 having the above configuration will be described. In the distillation column 2, steam for heating is blown in to perform steam stripping. That is, in the distillation column 2, the stock solution is brought into contact with steam for heating, ammonia is separated from the stock solution and gasified, and discharged as a vapor containing ammonia from the top of the column, and low-concentration ammonia water from which ammonia is removed from the stock solution (for example, For example, 30 ppm or less) is stored at the bottom of the column as treated water.

The ammonia-containing vapor discharged from the top of the distillation column 2 is guided through the vapor supply pipe L10 to the header 16R on the upstream side of the upstream evaporator 3A, and further passes through the heat transfer tube group 15A. The circulating liquid (water) sprayed by the spreader 13A by circulating through it evaporates as a thin film on the surface of the heat transfer tube group 15A, thereby generating water vapor. This water vapor is supplied to the upstream steam compressor 18A. On the other hand, condensed water (low-concentration ammonia water) condensed by circulating in the heat transfer tube group 15A is stored in the downstream header 16L, and the upstream header and heat transfer tube group in the tube L19 and the downstream evaporator 3B. and a downstream header, and is returned to the top of the distillation column 2 as a reflux liquid through a tube L11, and the remaining excess vapor (concentrated ammonia-containing vapor) passes through a tube L12 to the concentration column 5 ) is supplied to

In the compression device 18 (steam compressors 18A and 18B), the supplied water vapor is compressed and heated, and is fed to the bottom of the distillation column 2 as water vapor for heating. Thereby, the steam for heating supplied from the steam supply pipe L3 for a heating can be reduced, and energy saving can be aimed at.

In addition, in the ammonia recovery device 1 according to the present embodiment, as described above, the evaporator 3 has two evaporators as two split evaporators, namely, an upstream evaporator 3A and a downstream evaporator 3B. is connected in series along the flow direction of ammonia-containing vapor, and the upstream side evaporator 3A and the downstream side evaporator 3B are respectively a temperature increasing means, an upstream steam compressor 18A and a downstream steam compressor 18B. ) is provided, and among the two evaporators 3A and 3B, the vapor compressor 18A provided in the evaporator 3A on the upstream side in the flow direction of the ammonia-containing vapor is provided in the evaporator 3B on the downstream side. It has the characteristic structure that the temperature difference at the time of compressing and heating up water vapor|steam is smaller than (18B). Hereinafter, this characteristic structure is specifically supplemented and demonstrated.

As shown in FIG. 2 , overhead vapor (ammonia-containing vapor) is supplied to the evaporator 3 from the top of the distillation column 2, and the ammonia concentration in the overhead vapor is 4.94 wt%, and the evaporator The temperature until introduced in (3), that is, the inlet temperature T5 in the upstream evaporator 3A is 98.6°C. In the evaporator 3 , the overhead vapor exchanges heat with water outside the tube supplied through the tube L8 , and a part of the overhead vapor condenses to become a liquid, thereby decreasing the temperature of the overhead vapor.

Here, the gas-liquid equilibrium diagram at atmospheric pressure (760 mmHg) of a mixture consisting of water and ammonia is shown in FIGS. 4 and 5 . 4 is a graph describing the ammonia concentration from 0 to 100%, and FIG. 5 is a graph describing only the ammonia concentration from 0 to 50%. This graph also shows the boiling point (x1) and the dew point (y1) of the mixture of water and ammonia at atmospheric pressure, and the dew point is the same as the saturated steam temperature.

As shown in Fig. 5, for example, when the mixture is at 87.6°C at atmospheric pressure (760 mmHg), since this mixture is in an equilibrium state, the temperature is on both the air side (y1) and the liquid side (x1). is the same as 87.6 °C. At this time, the ammonia concentration on the base side y1 is 37.93 wt%, while the ammonia concentration on the liquid side x1 is 3.79 wt%. Then, for example, if the overhead vapor drops from 98.6°C to 87.6°C, the ammonia concentration rises from 4.94 wt% to 37.93 wt%, while the ammonia concentration of the condensed liquid becomes 3.79 wt%. That is, the ammonia concentration on the base side y1 of the mixture of water and ammonia increases, while the ammonia concentration on the liquid side x1 decreases. Therefore, as described above, the ammonia concentration of the overhead vapor was 4.94 wt% at the inlet of the evaporator, but when heat exchanged with water outside the tube in the evaporator, the ammonia concentration of the overhead vapor at the outlet of the evaporator rises from 4.94 wt% On the other hand, in the condensed liquid, the ammonia concentration becomes thinner than 4.94 wt%, and it is returned to the distillation column as a reflux liquid, and ammonia is recovered again.

At this time, in the ammonia recovery apparatus 1 according to the present embodiment, as described above, since the evaporator 3 is divided into an upstream evaporator 3A and a downstream evaporator 3B, the distillation column 2 is The top steam supplied from the top of the evaporator is first used as heated steam of the upstream evaporator 3A. The steam temperature at this time is 98.6°C as described above. In the upstream evaporator 3A, part of the overhead vapor condenses, so that the ammonia concentration of the overhead vapor rises. For example, assuming that the ammonia concentration rises from 4.94 wt% to 20%, from the graph, the saturated vapor temperature y1 at the ammonia concentration of 20 wt% is about 93°C, resulting in an ammonia-containing vapor at 93°C. Since this 93 degreeC ammonia-containing vapor|steam becomes the heated steam of the downstream evaporator 3B, the evaporation temperature of water falls compared with the upstream evaporator 3A (heated steam 98.6 degreeC).

As described above, after heat exchange in the evaporator, the ammonia concentration of the overhead vapor increases, and when the ammonia concentration increases, the temperature of the overhead vapor decreases.

Based on the above principle, here, as a modified example for comparison and comparison with the ammonia recovery device 1, for example, as shown in FIG. 6 , the evaporator is not divided into a plurality of split evaporators, but is a single evaporator. It is comprised only by 3 C of evaporators, and the structure which connected two vapor compressors 18C and 18D in parallel to this evaporator 3C as a temperature raising means is given. In this modified example, the inlet temperature T1 of the overhead vapor (ammonia-containing vapor) in the evaporator 3C is 98.6°C as described above, but in the evaporator 3C, the water outside the tube supplied through the tube L8 and In the overhead steam after heat exchange, the ammonia content rises to 36.38 wt% and the outlet temperature T2 drops to 88.3°C. For this reason, the temperature T3 of the water vapor supplied to the vapor compressors 18C and 18D from the upper part of the evaporator 3C cannot but fall to 85.6°C, and therefore, in this modification, this water vapor is converted into the vapor compressors 18C and 18D. Thus, the temperature is increased by compression to a temperature of T4 = 100°C, and it is poured into the bottom of the distillation column 2 to be reused as steam for heating. That is, in this case, all compression temperatures T4-T3 in two steam compressors 18C and 18D will be 100-85.6=14.4 degreeC.

On the other hand, referring again to FIG. 2 which shows the main part of the ammonia recovery apparatus 1 which concerns on this embodiment, the ammonia content in the overhead vapor|steam is 4.94 wt%, the inlet temperature T5 in the evaporation part 3 is 98.6 degreeC, and evaporation The outlet temperature T6 after being discharged from the section 3 is 88.3°C (ammonia content 36.38wt%), and the temperature T7 of the water vapor supplied from the upper part of the downstream evaporator 3B to the downstream steam compressor 18B is 85.6°C. is not different from the case of the above modification, but the outlet temperature T8 of the ammonia-containing vapor in the upstream evaporator 3A becomes about 97.2° C. (ammonia content about 10 wt%), and the outlet temperature T6 in the downstream evaporator 3B (88.3 DEG C), the temperature T9 of the water vapor supplied to the upstream steam compressor 18A from the upper portion of the upstream evaporator 3A can be set at about 95 DEG C. As a result, the compression temperature T10-T7 in the downstream steam compressor 18B is 100-85.6 = 14.4 DEG C, which is not different from the case of the above modification, but the compression temperature T10 in the upstream steam compressor 18A. -T9) is 100-95.0 = 5.0°C, which results in a smaller compression than in the case of the above modification. That is, the load on the upstream side vapor compressor 18A is reduced.

Therefore, according to the ammonia recovery device 1 according to the present embodiment, (I) first, the power consumption is reduced as the compression temperature in the upstream steam compressor 18A ends at 5°C, so running cost is reduced. The merit that it can reduce is acquired.

Although this reduction amount of running cost also fluctuates with the scale of an apparatus, it is computed as follows, for example. That is, if the total amount of water vapor (per two steam compressors) that is compressed and heated by the temperature increasing means from the evaporator and injected into the bottom of the distillation column 2 is 4,000 kg/hr (= 96 ton/day), the above In the case of the modification, the power consumption per unit of the steam compressors 18C and 18D is 2,000 kg/hr × 65 kWh/ton = 130 kW, and in two units, it is 130 kW × 2 = 260 kW. Accordingly, the electricity cost is 260 kW × 15 yen/kWh × 24 = 93,600 yen/day × 300 = 28,080,000 yen/year.

On the other hand, in the case of the ammonia recovery device 1 according to the present embodiment, the power consumption of the upstream steam compressor 18A is 2,000 kg/hr × 30 kWh/ton = 60 kW, and the power consumption of the downstream steam compressor 18B is becomes 2,000kg/hr×65kWh/ton=130kW, and 60kW+130kW=190kW for two units. Accordingly, the electricity cost is 190 kW × 15 yen/kWh × 24 = 68,400 yen/day × 300 = 20,520,000 yen/year, which is a cost reduction of about 7.5 million yen/year compared to the case of the above modification.

(II) Second, since the temperature T9 of the water vapor supplied from the upper part of the upstream side evaporator 3A to the upstream side steam compressor 18A can be kept at a high temperature of about 95°C without dropping too much, the water vapor The specific volume becomes small, and accordingly, the merit that the upstream side vapor compressor 18A can be made into a small size is acquired by that much.

In this case, in addition to making only the upstream side steam compressor 18A small in size, for example, it is also possible to make both the upstream side steam compressor 18A and the downstream side steam compressor 18B into small sizes on average. More specifically, for example, if the size of the two steam compressors 18C and 18D according to the modification example is the same and is 5:5, the ammonia recovery device 1 according to the present embodiment is on the upstream side. In addition to the size of the steam compressor 18A and the downstream steam compressor 18B being 3:5, for example, it is also possible to set it to 4:4.

Also, if it is assumed that the overhead vapor generated from the distillation column does not contain ammonia, the temperature of the overhead vapor is 100°C. In the heat exchange in the evaporator, water is heated by latent heat generated when the overhead vapor changes from gas to liquid, and part of the overhead vapor is condensed by this heat exchange, but when the overhead vapor does not contain ammonia, The temperature of the overhead steam remains unchanged at 100° C. even after heat exchange. Therefore, in this case, regardless of the number of evaporators, the temperature of the water vapor generated from all evaporators becomes the same, and the effect of the present invention cannot be obtained. (However, in a real device, the temperature drops somewhat due to other factors.)

In addition, in the ammonia recovery apparatus 1 according to the present embodiment, even if the heated steam temperature in the upstream evaporator 3A and the downstream evaporator 3B was, for example, 98.6°C and 93°C of 100°C or less. , As described above, the outside of the heat transfer tube of the evaporator 3 is at a low pressure (atmospheric pressure or less) by the compression device 18, so that water can be evaporated even by heating steam at 100°C or less.

Next, returning to the description of the processing operation of the ammonia recovery apparatus 1 according to the present embodiment again, as shown in FIG. 3 , in the concentration tower 5 , the control valve according to the detection result of the temperature sensor T The opening degree of (V1) is controlled, and the flow rate of the cooling water passing through the heat exchanger (H4) is adjusted. Thereby, the storage liquid (condensate) cooled to a predetermined temperature is sprayed from the tower top of the concentration tower 5, and the ammonia-containing vapor is condensed, so that the ammonia-containing vapor of a predetermined high concentration (for example, 20 wt% or more) is is created In addition, the entire amount of the condensate is returned to the top of the distillation column 2 as a reflux liquid. As described above, in the concentration tower 5, the ammonia-containing vapor after being separated by the evaporator 3 is put in, and moisture is removed to further concentrate the ammonia-containing vapor by the evaporator 3 alone. Compared with the configuration in which the concentration is concentrated to a predetermined high concentration (for example, 20 wt% or more), the load of the compression device 18 can be further reduced. As a result, energy saving is attained, and it becomes possible to produce|generate the ammonia containing vapor|steam of high concentration (for example, 20 wt% or more).

Next, as shown in FIG. 1, in the 1st absorption tower 6, by the structure which sprays the storage liquid of the tower bottom from the tower top through the spray pipe L23, the tube from the concentration tower 5 The ammonia-containing vapor guided through L24 is condensed to produce ammonia recovery water (recovered ammonia water) containing a high concentration of ammonia. In the second absorption tower 7, the uncondensed ammonia gas slightly remaining in the first absorption tower 6 is guided through the pipe L32, and water supplied from outside the system is supplied through the spray pipe L31 to the top of the tower. The non-condensed ammonia gas is absorbed by the configuration sprayed from the . The water which absorbed ammonia is returned to the condensate of the 1st absorption tower (6). As a result, uncondensed ammonia gas is prevented from being discharged to the outside. Further, the gas from which ammonia has been removed is exhausted from the exhaust pipe L34.

(Other matters)

(1) In the above embodiment, the description was given as a configuration in which "water" is supplied to the evaporator 3 and the second absorption tower 7, but specifically, this "water" is pure water, soft water, or ion-exchanged water. etc. can be applied.

(2) Also, for reference, in the case of a configuration in which the vapor of the distillation column is directly compressed and used as a heat source for the distillation column (for example, Patent Document 1, etc.), by directly compressing the vapor of the distillation column, There is a risk of corrosion, and there is a possibility of corrosion or leakage in the seal part. On the other hand, in the case of a configuration in which water is evaporated with an evaporator and directly used in the distillation column as in the above embodiment, since the vapor (water vapor) directly used in the distillation column does not contain contained substances, corrosion or leakage by the contained substances can prevent the occurrence of

(3) In the above embodiment, as the evaporator 3, the upstream evaporator 3A and the downstream evaporator 3B, which are two evaporators, are used, ie, two evaporators are used as the two divided evaporators. However, as the two split evaporators, for example, as shown in Figs. 7 and 8 , those formed by dividing one evaporator may be used.

In the example shown in FIG. 7 and FIG. 8, the evaporation can 20 which has a substantially horizontally long cylindrical external shape is lateral by the partition plate 21 extended along the axial direction from the center in a standing board shape. It divides so that it may be divided into 2 minutes in a direction, and by this, the upstream side evaporation part 20A and the downstream side evaporation part 20B are formed in the said evaporation can 20. As shown in FIG. A first header 22 having a substantially rectangular parallelepiped shape is provided on one end surface of the evaporation can 20 , and a second header 23 having a substantially rectangular parallelepiped shape is provided on the other end surface of the evaporation can 20 . is provided.

The upstream evaporator 20A is provided with a heat transfer tube group 24A composed of one or more horizontal heat transfer tubes, and the bottom of the upstream evaporator 20A serves as a reservoir for storing water supplied from outside the system. , the storage liquid (water) of the storage is supplied to the spreader 27A provided in the upper part of the upstream evaporator 20A through the pipe L26A by the circulation pump P25A, and from the spreader 27A After spraying toward the outer surface of 24 A of heat transfer tube groups, it is comprised so that it may circulate so that it may flow into the lower storage part in 20 A of upstream evaporation parts.

The downstream evaporator 20B is configured substantially symmetrically with the upstream evaporator 20A, and for this reason, a detailed description thereof is omitted. The first header 22 is connected to the top of the distillation column (not shown) through a steam supply pipe L28, and the top steam (ammonia-containing steam) discharged from the top of the distillation column is supplied through a steam supply pipe L28. It is guided to the first header 22, circulates in the heat transfer tube group 24A of the upstream evaporator 20A, is bent in the second header 23, and is a group of heat transfer tubes of the downstream evaporator 20B. It flows through the inside of 24B, is discharged|emitted from the 1st header 22, and is supplied to a concentration tower or an absorption tower (not shown) through the pipe|tube L29. An upstream vapor compressor 30A is connected to an upper portion of the upstream evaporator 20A, and a downstream vapor compressor 30B is connected to an upper portion of the downstream evaporator 20B.

With the above configuration, the upstream evaporator 20A and the downstream evaporator 20B can perform the same functions as the upstream evaporator 3A and the downstream evaporator 3B according to the embodiment. In this way, since the two evaporators 20A and 20B are formed by dividing the evaporator can 20 which is one evaporator, it is possible to achieve compactness of the apparatus and reduction of cost compared with the configuration using two evaporators. can

(4) In the above embodiment, as the upstream and downstream steam compressors 18A and 18B, the same route type steam compressor is used. For example, the temperature increasing means provided in the upstream split evaporator is provided on the downstream side. It is good also as a structure smaller than the temperature raising means provided in the divided evaporation part of . According to this configuration, the device can be further energy-saving or compact. For example, as described above, in the present invention, since the temperature increase means (upstream steam compressor 18A) provided in the upstream split evaporator ends with a slight compression, the upstream temperature increase means is changed to a turbo type steam compressor. doing, etc. Further, for example, by preparing three or more temperature raising means, dividing them into two groups, and configuring one group by fewer temperature raising means than the other group, smaller temperature increase than the other. It's okay to configure the means. For example, there is a configuration in which one steam compressor is used as an upstream temperature increasing means and two steam compressors are connected in series and used as a downstream temperature increasing means. In particular, in this case, these sum total It is also possible to reduce the initial cost by using the same relatively inexpensive steam compressor as the three steam compressors.

In addition, as the temperature increase means, in addition to steam compressors (heat pumps) such as a root type steam compressor, a turbo type steam compressor, a screw type steam compressor, and a vane type steam compressor, for example, as shown in FIG. 9 , a steam ejector or the like is used. it's ok to do In the example shown in FIG. 9, in the ammonia recovery apparatus 1 which concerns on the said embodiment, it is a structure in which the vapor ejector 31 was provided as an upstream temperature raising means instead of the upstream vapor compressor 18A. The steam ejector 31 is a steam ejector provided as a means for supplying steam for heating to the bottom of the distillation column 2 through a steam supply pipe L3 for heating in the ammonia recovery apparatus 1 according to the above embodiment ( 10), and to the steam intake side 31a, a steam supply pipe L32 through which steam supplied from a high-pressure steam source (not shown) such as a boiler flows is connected, and the steam is supplied to the upstream evaporator ( It is mixed with the steam supplied from 3A) through the pipe L15, and is blown into the bottom of the distillation column 2 through the pipe L16 as steam for heating.

In the upstream temperature raising means, since the required compression temperature is small, the suction ratio (efficiency) can be improved even with the configuration using the steam ejector as described above. When a steam ejector is used, compared to the case of using a steam compressor (heat pump) such as a root type steam compressor, a turbo type steam compressor, a screw type steam compressor, and a vane type steam compressor, the running cost increases, but the initial cost can be reduced. can The use of a steam ejector may be advantageous in some cases, depending on the amount of processing in the device, power, industrial water, and the like.

(4) In the above embodiment, as the evaporator 3, the configuration using the upstream evaporator 3A and the downstream evaporator 3B, which are two evaporators, that is, a configuration in which two divided evaporators were provided, but divided evaporation It's okay to have three or more wealth. Even if there are three or more divisional evaporation parts, the temperature difference of the temperature increase by a temperature raising means becomes small as much as it becomes an upstream divisional evaporation part, and energy saving can be attained by this.

Moreover, when forming two divisional evaporation parts by dividing one evaporator, it is good also considering the division|segmentation number being made more and making three or more division|segmentation evaporation parts dividedly formed.

(5) In the above embodiment, the concentration column 5 is provided at the rear end of the evaporation unit 3, and the ammonia-containing vapor discharged from the distillation column 2 is separated by the evaporation unit 3 and the concentration tower 5. Although it was comprised so that ammonia water of a predetermined high concentration (for example, 20 wt% or more) could be collect|recovered by two-step concentration, you may abbreviate|omit the concentration tower 5 in this invention.

Moreover, in the said embodiment, the 1st absorption tower 6 which absorbs water|moisture content into the ammonia-containing vapor|steam from the concentration tower 5, and produces|generates recovered ammonia water of predetermined concentration, and the uncondensed ammonia-containing vapor|steam in the 1st absorption tower. Although it has a structure provided with the second absorption tower 7 for preventing the carbon dioxide from being discharged to the outside, for example, instead of the first absorption tower 6 and the second absorption tower 7, a catalytic cracking device is provided. It is provided and it is good also as a structure which removes by decomposing|decomposing ammonia with a catalyst.

In other words, in the heterogeneous substance separation apparatus according to the present invention, the heterogeneous substance such as ammonia separated from the stock solution by the processing operation from the supply of the stock solution from outside the system to the heat exchange in the evaporator may be treated thereafter, For example, you may make it collect|recover like the said embodiment, or you may make it decompose|disassemble and remove.

[Industrial Applicability]

The present invention is applied to a separation apparatus and separation method for separating heterogeneous substances such as the low-boiling substances from a stock solution containing two or more substances, such as wastewater containing low-boiling substances such as ammonia. It is possible.

1: Ammonia recovery device (separation device for dissimilar substances)
3: Evaporation part
3A: Upstream evaporator (split evaporator)
3B: Downstream evaporator (split evaporator)
18: Compression device (temperature increase means)
18A: Upstream side steam compressor (temperature raising means)
18B: Downstream steam compressor (temperature raising means)

Claims (9)

A first vapor is generated from an undiluted solution containing two or more substances, introduced into an evaporator, and the first vapor is heat-exchanged with a liquid, whereby the first vapor is condensed. ) and concentrated, and the liquid is evaporated and discharged as a second vapor, and the second vapor is heated by a temperature increasing means to separate the heterogeneous substance used for generating the first vapor as a heating vapor. As a device,
The evaporator has a configuration in which at least two split evaporators are connected in series along a flow direction of the first vapor, and the temperature increase means is provided in each of the two split evaporators,
Among the two split evaporators, the temperature raising means provided in the split evaporator on the upstream side in the flow direction of the first steam increases the temperature of the second steam more than the temperature increase means provided in the split evaporator on the downstream side. Separation device for heterogeneous materials, characterized in that the temperature difference is small. The method according to claim 1,
The separation device for dissimilar substances in which the two split evaporators are formed by dividing one evaporator. The method according to claim 1,
means for generating the first vapor from the stock solution, the first steam comprising the at least one heterogeneous substance by contacting the stock solution with steam for heating, separating and gasifying at least one heterogeneous substance from the stock solution A device for separating heterogeneous substances, comprising a distillation column for discharging from the top of the column as a furnace and storing a treatment liquid from which the one or more kinds of foreign substances have been removed from the stock solution at the bottom of the column. 3. The method according to claim 2,
means for generating the first vapor from the stock solution, the first steam comprising the at least one heterogeneous substance by contacting the stock solution with steam for heating, separating and gasifying at least one heterogeneous substance from the stock solution and a distillation column for discharging from the top of the column and storing the treatment liquid from which the one or more kinds of different substances have been removed from the stock solution at the bottom of the column. 5. The method according to any one of claims 1 to 4,
The apparatus for separating a dissimilar material, wherein the temperature raising means provided in the upstream split evaporator is smaller than the temperature raising means provided in the downstream split evaporator. 5. The method according to any one of claims 1 to 4,
The separation device for heterogeneous substances in which the undiluted solution contains water and a low-boiling-point substance. 5. The method according to any one of claims 1 to 4,
The separation device for the dissimilar material, wherein the temperature raising means includes a heat pump and/or a vapor ejector. The undiluted solution containing the low boiling point substance is brought into contact with steam for heating, the low boiling point substance is separated from the undiluted solution and gasified, and discharged from the top of the tower as a vapor containing the low boiling point substance, and treated water from which the low boiling point substance has been removed from the undiluted solution is discharged into the tower. a distillation column stored at the bottom,
By exchanging water with the vapor containing the low boiling point material discharged from the top of the distillation column, the vapor containing the low boiling point material is condensed to concentrate the vapor containing the low boiling point material, and the water is evaporated and an evaporator for discharging as water vapor;
A device for separating heterogeneous substances comprising a compression device for compressing and increasing the temperature of the steam discharged from the evaporation unit, guiding the compressed temperature of the steam to the distillation column, and using it as heating steam used in the distillation column,
The evaporator has a configuration in which at least two split evaporators are connected in series along a flow direction of the vapor containing the low boiling point substance, and the compression device is provided in each of the two split evaporators,
Among the two split evaporators, the compression device provided in the split evaporator on the upstream side in the flow direction of the vapor containing the low boiling point compresses the water vapor more than the compression device provided in the split evaporator on the downstream side. A device for separating heterogeneous substances, characterized in that the temperature difference is small when the temperature is raised. A first vapor is generated from an undiluted solution containing two or more substances and introduced into an evaporator, and the first vapor is heat-exchanged with a liquid, whereby the first vapor is condensed and concentrated, and the liquid is A method of separating a heterogeneous substance that is evaporated and discharged as a second vapor, and the second vapor is heated by a temperature increasing means to generate the first vapor as a heating vapor,
the evaporator has a configuration in which at least two split evaporators are connected in series along a flow direction of the first vapor, and the temperature increase means is provided in each of the two split evaporators;
Among the two split evaporators, the temperature raising means provided in the split evaporator on the upstream side in the flow direction of the first steam increases the temperature of the second vapor more than the temperature increase means provided in the split evaporator on the downstream side. A method for separating heterogeneous materials, characterized in that the temperature difference between them becomes small.

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