TW202120162A - Separation device and separation method for different substances capable of effectively using the heat of the ammonia-containing steam for saving energy and lowering operation cost - Google Patents

Abstract

The invention provides a separation device and separation method for different substances for energy saving. The separation device for different substances (ammonia recycling device (1)) generates a first steam (ammonia-containing steam) from the stock solution (ammonia-containing discharged water) and introduces into an evaporation portion (3) to perform heat exchange with liquid (water). Thus, the first steam may be partially condensed and concentrated to evaporate the liquid as the second steam (water steam) to be discharged. The second steam may be heated by a heating means (compression device 18) as heating steam for generating the first steam. The evaporation portion (3) is composed of at least two divided evaporation portions (evaporators (3A, 3B) at the upstream side and at the downstream side) that are series connected along the flowing direction of the first steam. The two divided evaporation portions are respectively configured with a heating means (steam compressors 18A, 18B at the upstream side and at the downstream side), wherein the heating means at the upstream side has less temperature difference while heating the second steam than that of the heating means at the downstream side.

Description

Separating device and method for dissimilar substances

The present invention relates to a separation device and a separation method for separating dissimilar substances such as low boiling point substances from a raw liquid composed of two or more substances. The raw liquid is waste water containing low boiling substances such as ammonia.

For example, as a method for separating and removing ammonia-containing waste water, a steam stripping method is known. A general ammonia recovery device using this vapor stripping method is equipped with a distillation column for vapor stripping. The ammonia-containing vapor discharged from the top of the distillation column is partially condensed by a condenser, and the condensed water is used as reflux The liquid is returned to the top of the distillation tower, and the remaining concentrated ammonia-containing vapor is supplied to the absorption tower to absorb water and be taken out as recycled ammonia.

However, the vapor stripping method used in such an ammonia recovery device is a method in which water vapor is directly blown into the bottom of the distillation tower. Because a large amount of water vapor is used, the operation cost is high, and it is required to reduce the processing cost. On the other hand, in this method, ammonia-containing water vapor is generated approximately the same amount as the injected water vapor. In order to make it the reflux liquid to the top of the distillation column and to recover the ammonia liquid, it must be installed at the top of the tower. The heat exchanger (condenser) cools, and the energy becomes disposable.

In order to solve this problem, a technique for compressing the vapor discharged from the top of the distillation column by a vapor compressor and recovering heat by a reboiler to reduce the amount of water vapor has been proposed (see Patent Document 1 below) . In addition, the condenser that partially condenses the ammonia-containing vapor discharged from the top of the distillation column is supplied with make-up water, and the make-up water and the ammonia-containing vapor are heat exchanged to evaporate, and the make-up water is introduced into the vapor compressor for compression. The technology of increasing the temperature and reusing it as water vapor has been proposed (refer to Patent Document 2 below). [Prior Technical Literature] [Patent Literature]

[Patent Document 1] JP 2002-28637 A [Patent Document 2] JP 2004-114029 A

[The problem to be solved by the invention]

The previous examples disclosed in the above-mentioned Patent Documents 1 and 2 effectively utilize the heat of the ammonia-containing vapor discharged from the top of the distillation column, which can achieve energy saving and reduce operating costs.

However, in the structure of the previous example including at least a distillation column, a heat exchanger (a reboiler or a condenser, a reboiler or a condenser is equivalent to the evaporator of the present invention), and a vapor compressor, if you want to recover For example, high-concentration ammonia of 20 wt% or more will cause the following problems. That is, if it is desired to increase the concentration to a high concentration only by the heat exchanger (equivalent to the evaporator of the present invention), the temperature difference between the inlet and outlet of the ammonia-containing vapor of the heat exchanger becomes larger, causing the load of the vapor compressor to change. If it is too large, it does not meet the requirements for energy saving by using a vapor compressor. In addition, the above-mentioned problems are not limited to recovery devices containing ammonia, and are common problems with recovery devices containing low-boiling substances. Therefore, a low-boiling-point material recovery device that can achieve effective energy saving has been desired.

The present invention was developed in view of the above-mentioned problems, and its purpose is to provide a separation device and a separation method for foreign substances that can achieve effective energy saving. [Technical means to solve the problem]

In order to achieve the above-mentioned object, the separation device for dissimilar substances of the invention described in claim 1 generates a first vapor from a raw liquid composed of two or more substances and introduces the first vapor into the evaporator to exchange heat between the first vapor and the liquid. Thereby, the first vapor is partially condensed and concentrated, and the liquid is evaporated to be discharged as the second vapor, and the second vapor is raised by a heating means to be used as heating vapor for the generation of the first vapor, The evaporator is characterized in that at least two divided evaporators are connected in series along the flow direction of the first vapor, and the temperature rise means are provided in the two divided evaporators, respectively, and are installed in the two evaporators. In the divided evaporator, the temperature difference of the divided evaporator on the upstream side in the flow direction of the first vapor in the flow direction of the divided evaporator is higher than the temperature difference of the divided evaporator provided on the downstream side when the temperature of the second vapor is raised. small.

According to the above configuration, because the temperature difference of the upstream heating means when raising the temperature of the second steam is smaller than that of the downstream heating means, the load applied to the upstream heating means is reduced, thereby achieving energy saving of the device . In addition, since the second vapor heated by the upstream heating means becomes relatively high temperature and its specific volume becomes smaller, the upstream heating means can be miniaturized.

The invention set forth in claim 2 is based on the separation device for dissimilar substances set forth in claim 1, in which the aforementioned two divided evaporators are formed by separating one evaporator. In the present invention, the terms "(divided) evaporator" or even "evaporator" can also be expressed as "(divided) heat exchange portion" or even "heat exchanger", for example.

As the two divided evaporators, for example, a configuration using two evaporators may be used. However, according to the configuration in which one evaporator is divided as described above, compactness of the device and cost reduction can be achieved.

The inventions set forth in claims 3 and 4 are based on the separation device for dissimilar substances set forth in claim 1 or 2, in which a distillation tower is provided as a means for generating the first vapor from the raw liquid, and in the distillation tower, The raw liquid is brought into contact with the steam for heating, and one or more foreign substances are separated from the raw liquid and vaporized to be discharged from the top of the tower as the first vapor containing the one or more foreign substances, and will be removed from the raw liquid After removing the above-mentioned one or more foreign substances, the treatment liquid is stored at the bottom of the tower.

According to the above-mentioned structure, the first steam can be appropriately generated by the steam stripping method, which is excellent in device compaction and processing stability.

The invention described in claim 5 is based on the separation device for dissimilar substances described in any one of claims 1 to 4, wherein the heating means of the divided evaporator provided on the upstream side is higher than that provided on the downstream side. The aforementioned heating means of the divided evaporator on the side is smaller. According to the above configuration, the device can be further energy-saving and even compact. In addition, one of the two heating methods is smaller than the other, which means that the power consumption and/or size of one heating method is smaller than that of the other heating method. In addition, for example, three or more temperature-raising means are prepared and divided into two groups, one of which is composed of a smaller number of temperature-raising means than the other group, whereby a smaller-sized temperature-raising means than the other can also be constructed.

The invention described in claim 6 is based on a separation device for dissimilar substances described in any one of claims 1 to 4, in which the original solution is composed of water and a low-boiling substance (in other words, the aforementioned two or more substances Contain at least water and low boiling point substances). As the "low boiling point substance", for example, a substance having a lower boiling point than water can be used. More specifically, alcohols such as ammonia and methanol, ketones such as acetone, and esters such as methyl acetate can be used. As "water", pure water, soft water, ion exchange water, etc. can be used.

The invention described in claim 7 is based on a separation device for dissimilar substances described in any one of claims 1 to 4, wherein the heating means includes a heat pump and/or a steam ejector. Examples of the "heat pump" include vapor compressors such as Roots vapor compressors, turbo vapor compressors, screw type vapor compressors, and vane type vapor compressors.

The separation device for dissimilar substances of the invention described in claim 8 is equipped with a distillation tower, an evaporator, and a compression device. The distillation tower allows the raw liquid containing the low boiling point substance to contact the heating water vapor, and the low boiling point substance is removed from the raw liquid Separate, let it vaporize and discharge from the top of the tower as a vapor containing low-boiling substances, and store the treated water after removing the low-boiling substances from the raw liquid at the bottom of the tower; The discharged steam containing low boiling point substances exchanges heat with water, thereby allowing the aforementioned low boiling point substance-containing vapor to be partially condensed to condense the aforementioned low boiling point substance-containing vapor, and allowing the aforementioned water to evaporate and be discharged as water vapor; The compression device compresses and raises the temperature of the water vapor discharged from the evaporation part, and introduces the compressed and temperature-rising water vapor into the distillation column, and uses it as heating water vapor used in the distillation column. It is characterized in that the evaporation part is It has a structure in which at least two divided evaporators are connected in series along the flow direction of the vapor containing the low-boiling substance. The compression device is installed in each of the two divided evaporators, and is installed in one of the two divided evaporators. The compression device of the split evaporator on the upstream side in the flow direction of the vapor containing the low-boiling substance has a smaller temperature difference when the water vapor is compressed and raised than the compression device provided on the downstream side of the split evaporator.

According to the above configuration, the temperature difference when the upstream compression device compresses and raises the temperature of water vapor is smaller than that of the downstream compression device, and the load applied to the upstream compression device is reduced, thereby achieving energy saving of the device. In addition, since the water vapor that is compressed and heated by the upstream side compression device becomes relatively high temperature, its specific volume becomes smaller, and the upstream side compression device can be miniaturized.

The method for separating dissimilar substances of the invention described in claim 9 is to generate a first vapor from a raw liquid composed of two or more substances and introduce it to an evaporator to exchange heat between the first vapor and the liquid, thereby allowing the aforementioned The first vapor is partially condensed and concentrated, and the liquid is evaporated to be discharged as the second vapor, and the second vapor is heated by a heating means to be used as heating vapor for the generation of the first vapor, characterized in that: The evaporation section is constructed by connecting at least two divided evaporating sections in series along the flow direction of the first vapor. The temperature increasing means is provided in each of the two divided evaporating sections, and one of the two divided evaporating sections is installed in The temperature difference of the temperature increase means of the split evaporator on the upstream side in the flow direction of the first steam when raising the temperature of the second steam is smaller than the temperature difference of the temperature rise means of the split evaporator provided on the downstream side.

According to the above configuration, it is possible to construct a separation method of dissimilar substances that can achieve effective energy saving. [Effects of Invention]

According to the present invention, effective energy saving can be achieved when dissimilar substances such as ammonia are separated from a raw liquid such as ammonia-containing wastewater.

Hereinafter, the present invention will be described in detail based on embodiments. In the following embodiment, an ammonia recovery device is taken as an example of a dissimilar substance separation device. The ammonia recovery device uses ammonia-containing waste water as a raw liquid, and separates, removes and recovers ammonia from the ammonia-containing waste water. As a dissimilar substance, in addition to ammonia, alcohols such as methanol, ketones such as acetone, and esters such as methyl acetate can also be used.

(Implementation form) Fig. 1 is an overall configuration diagram of the ammonia recovery device of the embodiment. The ammonia recovery device (corresponding to the foreign substance separation device of the present invention) 1 is equipped with: a distillation column that blows in heating water vapor to perform vapor stripping; 2. The ammonia-containing vapor discharged from the top of the distillation column 2 is combined with water. The evaporator 3 that allows the water to evaporate by heat exchange, compresses the temperature of the water vapor discharged from the evaporator 3, and is used as heating water vapor to be discharged to the compression device 18 of the distillation tower 2, and introduces the ammonia-containing vapor concentrated in the evaporator 3 and The vapor is cooled to remove moisture and increase the concentration of ammonia-containing vapor to a high concentration (for example, 20wt% or more) in the concentration tower 5, and the ammonia-containing vapor from the concentration tower 5 absorbs moisture to generate a predetermined concentration of recovered ammonia water. Tower 6, and the second absorption tower 7 to prevent the uncondensed ammonia-containing vapor in the first absorption tower from being discharged to the outside. Here, the outline of the ammonia recovery device 1 of this embodiment will be described. The evaporation section 3 has two evaporators 3A and 3B, which are two divided evaporators, connected in series along the flow direction of the ammonia-containing vapor. It is composed of two evaporators 3A and 3B respectively provided with vapor compressors 18A and 18B as heating means, and an evaporator 3A installed on the upstream side in the flow direction of the ammonia-containing vapor in the two evaporators 3A and 3B In the vapor compressor 18A, the temperature difference when the water vapor is compressed and heated is smaller than that of the vapor compressor 18B of the evaporator 3B installed on the downstream side.

Hereinafter, the specific structure of the ammonia recovery device 1 including the above-mentioned characteristic structure will be described. The distillation column 2 can use a multi-stage one, but it is not limited to this, and a non-multi-stage one can also be used. That is, the distillation tower 2 can use a layered tower or a packed tower. At the top of the distillation column 2, the raw liquid (ammonia-containing drainage) is supplied through the raw liquid supply pipe L1. The pH of the stock solution can be adjusted in advance.

At the bottom of the distillation column 2, the heating steam from the steam ejector 10 is supplied through the heating steam supply pipe L3. The bottom of the distillation column 2 is connected to the heat recovery tank 11 through a tube L4, and the retentate (low-concentration ammonia water) at the bottom of the column is supplied to the heat recovery tank 11 through the tube L4. The steam ejector 10 is a vapor compression means for suction and compression of steam. A steam supply pipe L5 and a steam reuse pipe L6 are connected to the steam suction side 10a. The steam supply pipe L5 is a high-pressure steam source (not shown) from a boiler, etc. ) The supplied steam circulates, and the steam reuse pipe L6 extends from the heat recovery tank 11. According to this structure, the stored liquid in the heat recovery tank 11 is flashed and sucked and compressed by the steam ejector 10, mixed with the steam from the steam supply pipe L5, and sent to the bottom of the distillation column 2 as heating steam Blow in. In this way, the stored liquid in the heat recovery tank 11 is flashed and reused as a part of the heating steam, thereby recovering heat.

A discharge pipe L7 for discharging treated water (for example, low-concentration ammonia water below 30 ppm) is connected to the bottom of the heat recovery tank 11, and the treated water discharge pump P1 and three heat exchangers H1 are installed on the discharge pipe L7. ,H2,H3. The heat exchanger H1 is a water heater that heats the water by exchanging heat with the treated water. The water heated by the heat exchanger H1 is supplied to the bottom of the evaporators 3A and 3B through the water supply pipe L8. The heat exchanger H2 is a raw liquid preheater that heats the raw liquid by exchanging heat with the treated water. The raw liquid preheated by the heat exchanger H2 is supplied to the top of the distillation column 2 through the raw liquid supply pipe L1. The heat exchanger H3 is a cooler that cools the treated water by exchanging heat between the cooling water and the treated water. The treated water cooled by the heat exchanger H3 is discharged to the outside 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 treated water discharge pump P1, and are installed in the following order. That is, in the discharge pipe L7, the heat exchanger H1 is provided on the upstream side of the heat exchanger H2. By installing in this order, since the amount of heat imparted by the treated water to the water is maximized, energy saving can be achieved in the evaporator 3 that heats the water. In addition, since the reason for installing the heat exchanger H3 is to cool the treated water, the heat exchanger H3 is installed on the downstream side than the heat exchangers H1 and H2.

The evaporator 3 is formed by connecting two evaporators 3A and 3B in series along the flow direction of the ammonia vapor between the top of the distillation tower 2 and the top of the concentration tower 5. The evaporator 3A And 3B are respectively composed of horizontal tube type evaporation cans 12A and 12B, and are provided with sprayers 13A and 13B and indirect heaters 14A and 14B. It is not limited to a horizontal tube type evaporation can, for example, a film-like flow down (vertical tube) type evaporation can can also be used. Two evaporators 3A and 3B are arranged on the upstream side in the flow direction of the overhead vapor (ammonia-containing vapor) discharged from the top of the distillation tower 2 and supplied to the vaporization section 3 through the vapor supply pipe L10 described later The indirect heater 14A in the evaporator (hereinafter also referred to as the "upstream evaporator") 3A, as shown in FIG. 2, is equipped with: a heat transfer tube group 15A composed of one or more horizontal heat transfer tubes, And a pair of headers 16R, 16L on the upstream side and the downstream side (right and left in the figure). In addition, the bottom of the evaporation tank 12A serves as a storage portion 17A that stores the water supplied from the permeation tube L8. The storage liquid (water) of the storage portion 17A is supplied to the sprayer 13A installed in the upper part of the evaporation tank 12A by the circulating pump P2A through the pipe L9A, and sprayed from the sprayer 13A toward the outer surface of the heat transfer tube group 15A, It flows down toward the storage part 17A in the lower part of the evaporation tank 12A, and such a cycle is performed. On the other hand, among the two evaporators 3A and 3B, the evaporator (hereinafter also referred to as "downstream evaporator") 3B arranged on the downstream side in the flow direction of the above-mentioned tower top vapor is an indirect heater 14B. The constitution of the storage portion 17B, the circulation pump P2B, the pipe L9B, and the sprayer 13B are all the same as in the case of the above-mentioned upstream side evaporator 3A, so the description is omitted.

The header box 16R on the upstream side of the upstream evaporator 3A is connected to the top of the distillation column 2 through the permeated steam supply pipe L10, and the overhead vapor (ammonia-containing vapor) discharged from the top of the distillation column 2 is passed through the vapor The supply pipe L10 is introduced into the header box 16R on the upstream side, and further circulates in the heat transfer pipe group 15A. Here, the upstream side evaporator 3A has a pressure lower than the pressure of the overhead vapor, so the circulating liquid (water) sprayed by the sprayer 13A is thin-film evaporation on the surface of the heat transfer tube group 15A to produce water Steam. This water vapor is supplied to the vapor compressor (hereinafter also referred to as "upstream vapor compressor") 18A provided in the upstream side evaporator 3A in the compression device 18. Here, the principle of vaporizing water in the upstream side evaporator 3A will be explained in more detail. In the upstream side evaporator 3A, there is more heated vapor than the top vapor (inside the heat transfer tube) which becomes the heating source. The pressure on the outside of the water heat transfer tube is low, so the water evaporates. The pressure difference is generated by the compression device 18 (specifically, the upstream side vapor compressor 18A). This is because the pressure outside the heat transfer tube of the evaporator connected to the suction side of the compression device 18 becomes lower, and the pressure of the top vapor in the distillation column 2 connected to the discharge side of the compression device 18 becomes higher. In addition, the steam supplied from the steam ejector 10 also increases the pressure in the distillation column 2 and becomes one of the reasons for evaporating the water in the upstream evaporator 3A. In addition, the condensed water (low-concentration ammonia water) circulating and condensed in the heat transfer tube group 15A is stored in the header tank 16L on the downstream side. The downstream header box 16L is a header box connected to the upstream side of the downstream side evaporator 3B. The condensed water (low-concentration ammonia water) stored in the header box 16L on the downstream side of the upstream side evaporator 3A permeates The pipe L19 is driven by the condensate pump P3 to pass through the pipe L11 from the header on the downstream side of the downstream evaporator 3B and return to the top of the distillation column 2 as a reflux liquid. The remaining residual vapor (concentrated ammonia-containing vapor) is discharged from the header box on the downstream side of the downstream evaporator 3B through the pipe L12 to the top of the concentration tower 5.

The compression device 18 includes, in addition to the above-mentioned upstream side vapor compressor 18A, a vapor compressor (hereinafter also referred to as "downstream side vapor compressor") 18B installed in the downstream side evaporator 3B, upstream and downstream side vapor compressors 18A and 18B respectively connect the bottom of the distillation column 2 to the upper part of the upstream side evaporator 3A and the downstream side evaporator 3B. That is, the inlet side of the upstream vapor compressor 18A is connected to the upper part of the evaporation tank 12A of the upstream evaporator 3A through the pipe L15, and the outlet side of the upstream vapor compressor 18A is connected to the distillation column 2 through the pipe L16. Connect at the bottom of the tower. The inlet side of the downstream vapor compressor 18B is connected to the upper part of the evaporation tank 12B of the downstream evaporator 3B through a permeate pipe L17, and the outlet side of the downstream vapor compressor 18B is connected to the bottom of the distillation tower 2 through a permeable pipe L18 .

Here, as the upstream side and downstream side vapor compressors 18A and 18B, Lu's vapor compressors with a large maximum differential pressure are used. However, in the present invention, it is not limited to a Lu's vapor compressor, and a turbo vapor compressor, a screw type vapor compressor, an impeller type vapor compressor, or other vapor compressors may be used. In addition, the compression device 18 in the present embodiment is composed of two vapor compressors 18A and 18B each on the upstream side and the downstream side. However, at least one of the upstream side and the downstream side is composed of two or more vapor compressors. A total of 3 or more vapor compressors are also possible.

As shown in Fig. 1, the concentration tower 5 is composed of a spray scrubber. The retentate (condensate) stored at the bottom of the concentration tower 5 flows through the spray pipe (corresponding to the circulation pipe of the present invention) L20, is directed to the top of the tower, and sprays toward the top of the tower. A circulation pump P4 and a heat exchanger H4 are provided in the middle of the spray pipe L20. The stored liquid flowing through the spray tube L20 exchanges heat with cooling water in the heat exchanger H4 to be cooled. As shown in Figure 3, a control valve V1 is installed in the pipe L21 through which the cooling water flows, and the opening degree is controlled by a temperature sensor T. The temperature sensor T is used to detect the bottom of the concentration tower 5 The temperature of the stored retentate. That is, the opening degree of the control valve V1 is controlled according to the detection result of the temperature sensor T, thereby adjusting the flow rate of the cooling water passing through the heat exchanger H4. Thereby, the stored liquid (condensate) is cooled to a predetermined temperature and sprayed, and a predetermined high-concentration (for example, 20 wt% or more) ammonia-containing vapor can be generated.

In addition, the spray pipe L20 is branched in the middle, and the branch pipe L22 of the branch is connected to the top of the distillation column 2. A control valve V2 is installed in the middle of the branch pipe L22. In addition, the concentration tower 5 is provided with a liquid level sensor S1 for detecting the liquid level of the storage liquid. The liquid level sensor S1 has: a level switch S1a for detecting the upper limit setting level, and a level switch S1b for detecting the lower limit setting level. The liquid level sensor S1 is used to control the opening of the control valve V2 to maintain the predetermined liquid level of the retentate, and return the retentate exceeding the predetermined liquid level to the top of the distillation tower 2.

As shown in Figure 1, the first absorption tower 6 is composed of the same spray scrubber as the concentration tower 5. The spray pipe L23 for circulating the retentate of the first absorption tower 6 is provided with a circulation pump P5 and heat Exchanger H5. In the heat exchanger H5, the stored liquid flowing through the spray tube L23 is cooled by heat exchange with cooling water. The cooled retentate is sprayed through the pipe L24 toward the high-concentration (for example, 20 wt% or more) ammonia-containing vapor introduced from the concentration tower 5, thereby condensing and recovering the ammonia-containing vapor to produce recovered ammonia water. The spray pipe L23 is branched in the middle, and the recycled ammonia is discharged out of the system through the branch pipe L25 of the branch.

The second absorption tower 7 is composed of the same spray scrubber as the first absorption tower 6. At the bottom of the second absorption tower 7, water is supplied through the pipe L30, and the water stored at the bottom of the tower is used by a circulating pump P6 is driven to spray from the top of the tower through the spray pipe L31. Installed between the first absorption tower 6 and the second absorption tower 7: the uncondensed ammonia-containing vapor in the first absorption tower 6 is introduced into the tube L32 at the top of the second absorption tower 7, and the second absorption tower 7 The condensed water returns to the pipe L33 of the first absorption tower 6. In addition, at the top of the second absorption tower 7 is provided an exhaust pipe L34 for exhausting vapor from which ammonia has been removed. In Figures 1 to 3, L40 is a cooling water supply pipe, L41 is a pipe branched from the cooling water supply pipe L40, L21 is a pipe branching from the cooling water supply pipe L40, and a heat exchange is provided on the cooling water supply pipe L40 For the device H5, a heat exchanger H3 is provided on the pipe L41, and a heat exchanger H4 is provided on the pipe L21.

Next, the processing operation of the ammonia recovery device 1 configured as described above will be described. In the distillation tower 2, steam is blown in by heating water vapor to perform vapor stripping. That is, in the distillation tower 2, the raw liquid is brought into contact with heated water vapor, the ammonia is separated from the raw liquid, and it is vaporized and discharged from the top of the tower as ammonia-containing vapor, and the low-concentration ammonia water after the ammonia is removed from the raw liquid ( For example, 30 ppm or less) is stored at the bottom of the tower as treated water.

The ammonia-containing vapor discharged from the top of the distillation tower 2 is introduced into the header box 16R on the upstream side of the upstream evaporator 3A through the vapor supply pipe L10, and then circulates in the heat transfer tube group 15A, thereby making the sprayer The circulating fluid (water) sprayed by 13A undergoes thin-film evaporation on the surface of the heat transfer tube group 15A to generate water vapor. This water vapor is supplied to the upstream side vapor compressor 18A. On the other hand, the condensed water (low-concentration ammonia) circulating in the heat transfer tube group 15A is stored in the header box 16L on the downstream side, and passes through the pipe L19 and the header on the upstream side of the downstream evaporator 3B. The box, the heat transfer tube group and the downstream header box are returned to the top of the distillation tower 2 as reflux liquid through the pipe L11, and the remaining residual vapor (concentrated ammonia vapor) is supplied to the concentration tower through the pipe L12 5.

In the compression device 18 (vapor compressors 18A and 18B), the supplied water vapor is compressed and increased in temperature, and is introduced into the bottom of the distillation column 2 as heating water vapor. Thereby, the heating water vapor supplied from the heating steam supply pipe L3 can be reduced, and energy saving can be achieved.

In addition, the ammonia recovery device 1 of this embodiment has the following characteristic structure as described above: The evaporation section 3 has two evaporators as two divided evaporators, that is, the upstream side evaporator 3A and the downstream side evaporator 3A. The side evaporator 3B is connected in series along the flow direction of the ammonia-containing vapor. The upstream side evaporator 3A and the downstream side evaporator 3B are respectively provided with an upstream side vapor compressor 18A and a downstream side vapor compressor 18B as heating means. The vapor compressor 18A of the evaporator 3A installed on the upstream side in the flow direction of the ammonia-containing vapor in the two evaporators 3A and 3B compresses and raises the water vapor. The temperature difference is greater than that of the vaporizer installed on the downstream side. The vapor compressor 18B of the device 3B is small. In the following, a specific supplementary explanation will be made for this feature structure.

As shown in Figure 2, overhead vapor (ammonia-containing vapor) is supplied from the top of the distillation tower 2 to the evaporation section 3. The ammonia concentration of the overhead vapor is 4.94 wt%, and the temperature before introduction into the evaporation section 3, namely The inlet temperature T5 of the upstream evaporator 3A was 98.6°C. In the evaporator 3, the above-mentioned overhead vapor and the water outside the tube supplied through the pipe L8 are heat exchanged, and a part of the overhead vapor is condensed into a liquid, thereby lowering the temperature of the overhead vapor.

Here, FIGS. 4 and 5 show the gas-liquid equilibrium curve diagrams of a mixture composed of water and ammonia at atmospheric pressure (760 mmHg). Fig. 4 is a graph of ammonia concentration from 0 to 100%, and Fig. 5 is a graph of ammonia concentration only in the range of 0 to 50%. The graph also shows the boiling point (x1) and dew point (y1) of the mixture of water and ammonia at atmospheric pressure, and the dew point is the same as the saturated vapor temperature.

As shown in Figure 5, for example, when the above mixture is 87.6°C under atmospheric pressure (760mmHg), the mixture is in equilibrium, so the temperature at the gas side (y1) or the liquid side (x1) is the same 87.6 ℃. At this time, the ammonia concentration on the gas side (y1) becomes 37.93 wt%, but the ammonia concentration on the liquid side (x1) becomes 3.79 wt%. In this way, for example, if the overhead vapor is cooled from 98.6°C to 87.6°C, the ammonia concentration increases from 4.94 wt% to 37.93 wt%. On the other hand, the ammonia concentration of the condensed liquid becomes 3.79 wt%. That is, the ammonia concentration on the gas side (y1) of the mixture of water and ammonia becomes higher, but the ammonia concentration on the liquid side (x1) decreases. Therefore, the above-mentioned overhead vapor has an ammonia concentration of 4.94wt% at the entrance of the evaporation section as described above. If the evaporation section exchanges heat with the water outside the tube, the ammonia concentration of the overhead vapor at the exit of the evaporation section becomes It is higher than 4.94wt%. On the other hand, the ammonia concentration of the condensed liquid becomes lower than 4.94wt%, and returns to the distillation column as reflux liquid, thereby allowing ammonia to be recovered again.

At this time, in the ammonia recovery device 1 of the present embodiment, as described above, the evaporator 3 is divided into the upstream evaporator 3A and the downstream evaporator 3B. Therefore, the overhead vapor supplied from the top of the distillation column 2 is first It is used as heating steam of the upstream evaporator 3A. The steam temperature at this time was 98.6°C as described above. In the upstream evaporator 3A, a part of the overhead vapor is condensed, and the ammonia concentration of the overhead vapor is increased. For example, if the ammonia concentration is increased from 4.94wt% to 20%, according to the graph, the saturated vapor temperature (y1) of 20wt% ammonia concentration is about 93°C, so it becomes 93°C ammonia-containing vapor. This 93°C ammonia-containing steam becomes the heating steam of the downstream evaporator 3B, so the evaporation temperature of water is lower than that of the upstream evaporator 3A (heating steam 98.6°C).

As described above, the ammonia concentration of the top vapor after the heat exchange in the evaporating section increases, and if the ammonia concentration increases, the temperature of the top vapor decreases.

Based on the above principles, here, as a modified example for comparison with the above-mentioned ammonia recovery device 1, as shown in FIG. 6, the evaporation part is not divided into a plurality of divided evaporation parts, but only a single evaporation part. The evaporator 3C is composed of two vapor compressors 18C and 18D, which are heating means, connected in parallel in the evaporator 3C. In this modified example, the inlet temperature T1 of the overhead vapor (ammonia-containing vapor) of the evaporator 3C is 98.6°C, which is the same as the above. In the evaporator 3C, it is combined with the water outside the tube supplied through the tube L8. After the heat exchange, the ammonia content in the top vapor of the tower rises to 36.38wt%, and the outlet temperature T2 drops to 88.3°C. Therefore, the temperature T3 of the water vapor supplied from the upper part of the evaporator 3C to the vapor compressors 18C and 18D has to be lowered to 85.6°C. Therefore, in this modified example, the water vapor is compressed and heated by the vapor compressors 18C and 18D. After reaching the temperature T4=100°C, it is put into the bottom of the distillation tower 2 and reused as heating water vapor. That is, in this case, the compression temperatures (T4-T3) of the two vapor compressors 18C and 18D both become 100-85.6= 14.4°C.

On the other hand, referring again to Fig. 2 showing the main part of the ammonia recovery device 1 of this embodiment, the ammonia content of the overhead vapor is 4.94 wt%, and the inlet temperature T5 of the evaporator 3 is 98.6°C, after being discharged from the evaporator 3 The outlet temperature T6 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 vapor compressor 18B is 85.6°C. This is the same as the above modified example. The situation is the same, but the outlet temperature T8 of the ammonia-containing vapor of the upstream side evaporator 3A becomes about 97.2°C (ammonia content is about 10wt%), and it does not drop to the level of the outlet temperature T6 (88.3°C) of the downstream side evaporator 3B, so The temperature T9 of the water vapor supplied from the upper part of the upstream side evaporator 3A to the upstream side vapor compressor 18A can be maintained at about 95°C. As a result, although the compression temperature (T10-T7) of the vapor compressor 18B on the downstream side is 100-85.6=14.4°C, which is the same as the case of the above modified example, if the compression temperature of the vapor compressor 18A on the upstream side (T10-T9) If it is 100-95.0=5.0°C, it is sufficient to perform a smaller compression than in the case of the above-mentioned modification example. That is, the load on the upstream side vapor compressor 18A is reduced.

Therefore, according to the ammonia recovery device 1 of this embodiment, (I) the first point, the compression temperature of the vapor compressor 18A on the upstream side can be 5°C, and the corresponding power consumption can be reduced, and the operation can be reduced. The cost benefit.

The amount of reduction in the operating cost varies depending on the scale of the device, but it is calculated as follows, for example. That is, if the total amount of water vapor (2 vapor compressors) injected into the bottom of the distillation column 2 from the evaporation section to be compressed and heated by the heating means is 4,000 kg/hr (=96 ton/day), in the above modification example In the case of, the power consumption per steam compressor 18C and 18D becomes 2,000kg/hr×65kWh/ton=130kW, and the total of the two compressors becomes 130kW×2=260kW. Therefore, the electricity cost becomes 260kW×15 yen/kWh×24=93,600 yen/day×300=28,080,000 yen/year.

In contrast, in the case of the ammonia recovery device 1 of the present embodiment, the power consumption of the upstream vapor compressor 18A is 2,000 kg/hr×30 kWh/ton=60 kW, and the power consumption of the downstream vapor compressor 18B is 2,000 kg/hr ×65kWh/ton=130kW, the total of 2 units is 60kW+130kW=190kW. Therefore, the electricity cost becomes 190kW×15 yen/kWh×24=68,400 yen/day×300=20,520,000 yen/year, which reduces the cost by approximately 7.5 million yen/year compared to the case of the above modification example.

(II) The second point is that the temperature T9 of the water vapor supplied from the upper part of the upstream side evaporator 3A to the upstream side vapor compressor 18A can be maintained at a high temperature of about 95°C. Therefore, the ratio of the water vapor The volume becomes smaller, and there is an advantage that the upstream side vapor compressor 18A can be downsized accordingly.

Also in this case, in addition to reducing the size of only the upstream side vapor compressor 18A, for example, both the upstream side vapor compressor 18A and the downstream side vapor compressor 18B can also be reduced in size evenly. More specifically, for example, when the dimensions of the two vapor compressors 18C and 18D in the above modified example are the same 5:5, in the case of the ammonia recovery device 1 of this embodiment, except for the upstream side vapor compressor The size of 18A and the downstream side vapor compressor 18B is set to other than 3:5, for example, it can also be set to 4:4.

In addition, if the overhead vapor generated from the distillation column does not contain ammonia, the temperature of the overhead vapor becomes 100°C. In the heat exchange of the evaporator, the water is heated by the latent heat generated when the overhead vapor changes from gas to liquid. This heat exchange condenses part of the overhead vapor, but when the overhead vapor is not In the case of ammonia, the temperature of the vapor at the top of the tower remains unchanged at 100°C even after the heat exchange. Therefore, in this case, regardless of the number of evaporators, the temperature of the water vapor generated from any evaporator becomes the same, and the effect of the present invention cannot be obtained. However, in a real device, the temperature will drop slightly due to other reasons.

In addition, in the ammonia recovery device 1 of the present embodiment, even if the heating vapor temperature of the upstream side evaporator 3A and the downstream side evaporator 3B is, for example, 98.6°C and 93°C, which are 100°C or less, as described above, because the evaporator 3 The outside of the heat transfer tube is reduced to a low pressure (below atmospheric pressure) by the compression device 18, and even if it is heated steam below 100°C, water can still evaporate.

Next, returning to the description of the processing operation of the ammonia recovery device 1 of this embodiment, as shown in FIG. 3, in the concentration tower 5, the control valve V1 is controlled according to the detection result of the temperature sensor T The opening degree is used to adjust the flow of cooling water passing through the heat exchanger H4. In this way, the retentate (condensate) cooled to a predetermined temperature is sprayed from the top of the concentration tower 5 to partially condense the ammonia-containing vapor, thereby generating a predetermined high-concentration (for example, 20 wt% or more) ammonia-containing vapor. The entire amount of the condensate is returned to the top of the distillation column 2 as reflux liquid. In this way, in the concentration tower 5, the ammonia-containing vapor partially condensed in the evaporator 3 is introduced, and after the moisture is removed, the ammonia-containing vapor is further concentrated. According to this configuration, compared to the concentration by the evaporator 3 only The predetermined high concentration (for example, 20 wt% or more) configuration can further reduce the load of the compression device 18. As a result, energy saving can be achieved, and high-concentration (for example, 20 wt% or more) ammonia-containing vapor can be generated.

Next, as shown in Fig. 1, in the first absorption tower 6, the stored liquid at the bottom of the tower is sprayed from the top of the tower through the spray pipe L23, and the ammonia-containing vapor introduced from the concentration tower 5 through the pipe L24 is condensed. And it produces ammonia recovery water (recovered ammonia water) containing high concentration of ammonia. In the second absorption tower 7, a trace amount of uncondensed ammonia gas remaining in the first absorption tower 6 is introduced through the pipe L32, and the water supplied from outside the system is sprayed from the top of the tower through the spray pipe L31, thereby absorbing the uncondensed ammonia gas. Condensed ammonia gas. The ammonia-absorbed water is returned to the condensate in the first absorption tower 6. As a result, it is possible to prevent the uncondensed ammonia gas from being discharged to the outside. The gas from which the ammonia has been removed is exhausted from the exhaust pipe L34.

(something else) (1) In the above-mentioned embodiment, the structure of supplying "water" to the evaporation part 3 and the second absorption tower 7 is described. Specifically, pure water, soft water, ion-exchanged water, etc. can be used for the "water".

(2) For reference, when the vapor of the distillation column is directly compressed and used as the heat source of the distillation column (for example, Patent Document 1, etc.), because the vapor of the distillation column is directly compressed, there is corrosion caused by the contained substances. Concerns, the possibility of corrosion and leakage of the sealing part. On the other hand, in the case of using an evaporator to evaporate water and directly using it in the distillation tower as in the above embodiment, since the vapor (steam) directly used in the distillation tower does not contain any substances, corrosion caused by the substances can be prevented. , The occurrence of leakage.

(3) In the above embodiment, as the evaporator 3, two evaporators, that is, the upstream evaporator 3A and the downstream evaporator 3B, are used, that is, two evaporators are used as the two divided evaporators. However, as two divided evaporators, for example, as shown in FIG. 7 and FIG. 8, they may be formed by dividing one evaporator.

In the example shown in FIGS. 7 and 8, the evaporation can 20 having a cylindrical shape with a substantially long lateral length is formed in the center by a partition 21 extending in a vertical plate shape along the axial direction. By dividing it into two halves, the upstream evaporation portion 20A and the downstream evaporation portion 20B are formed in the evaporation can 20. A first header box 22 having a substantially rectangular parallelepiped shape is provided on one end surface of the evaporation can 20, and a second header box 23 having a substantially rectangular parallelepiped shape is provided on the other end surface of the evaporation can 20.

A heat transfer tube group 24A composed of one or more horizontal heat transfer tubes is installed in the upstream evaporation section 20A. The bottom of the upstream evaporation section 20A serves as a storage section for storing water supplied from outside the system. (Water) is supplied to the sprayer 27A provided at the upper part of the upstream evaporation part 20A by the circulating pump P25A through the tube L26A. After spraying from the sprayer 27A toward the outer surface of the heat transfer tube group 24A, it is sprayed toward the outer surface of the heat transfer tube group 24A. The storage part at the lower part in the upstream evaporation part 20A flows down, and such a cycle is performed.

The downstream evaporating part 20B is configured to be substantially symmetrical to the above-mentioned upstream evaporating part 20A, and therefore a detailed description thereof will be omitted. The first header 22 is connected to the top of the distillation tower (not shown) through the vapor supply pipe L28. The top vapor (ammonia-containing vapor) discharged from the top of the distillation tower is introduced through the vapor supply pipe L28. The first header box 22 circulates in the heat transfer tube group 24A of the upstream evaporator 20A, and after being folded back in the second header box 23, circulates in the heat transfer tube group 24B of the downstream evaporator 20B, from the first The header tank 22 is discharged, and the pipe L29 is supplied to the concentration tower or the absorption tower (illustration omitted). The upstream vapor compressor 30A is connected to the upper part of the upstream evaporation part 20A, and the downstream vapor compressor 30B is connected to the upper part of the downstream evaporation part 20B.

According to the above configuration, the upstream side evaporator 20A and the downstream side evaporator 20B can perform the same functions as the upstream side evaporator 3A and the downstream side evaporator 3B of the above embodiment. In this way, the two evaporators 20A and 20B are formed by partitioning one evaporator, that is, the evaporator 20. Compared with the configuration using two evaporators, it is possible to achieve compactness and cost reduction of the device.

(4) In the above-mentioned embodiment, the upstream side and downstream side vapor compressors 18A and 18B are the same Lu's vapor compressors. However, for example, the heating means of the split evaporator installed on the upstream side is higher than that provided on the downstream side. The heating means of the divided evaporator on the side may be smaller. According to this structure, the device can be further energy-saving and even compact. For example, as described above, in the present invention, since the heating means (upstream vapor compressor 18A) of the split evaporator provided on the upstream side only needs to perform small compression, the upstream heating means can be changed to turbo vapor compression. Machine waiting. In addition, for example, three or more heating means are prepared and divided into two groups, one of which is composed of a smaller number of heating means than the other group, thereby forming a smaller heating means than the other. For example, one vapor compressor is used as the means for heating on the upstream side, and two steam compressors are connected in series as the means for heating on the downstream side. In this case, as a total of three steam compressors. The compressor can use the same vapor compressor which is cheaper and can reduce the initial cost.

In addition, as a means for raising temperature, in addition to vapor compressors (heat pumps) such as Lu's vapor compressors, turbo vapor compressors, screw vapor compressors, and impeller vapor compressors, for example, as shown in FIG. 9, steam can also be used. Injector, etc. In the example shown in FIG. 9, in the ammonia recovery device 1 of the above-mentioned embodiment, as the upstream side heating means, a vapor ejector 31 is provided instead of the upstream side vapor compressor 18A. The steam ejector 31 is the same as the steam ejector 10 in the ammonia recovery device 1 of the above-mentioned embodiment. The steam ejector 10 is a means for supplying heating water vapor to the bottom of the distillation column 2 through the heating steam supply pipe L3. The steam ejector 31 is connected to the steam suction side 31a with a steam supply pipe L32 through which steam supplied from a high-pressure steam source (not shown) such as a boiler circulates. The steam is supplied through the pipe L15 from the upstream evaporator 3A. After the steam is mixed, it is blown into the bottom of the distillation column 2 as a heating steam through the tube L16.

Since the heating means on the upstream side requires a small compression temperature, the suction ratio (efficiency) can be improved even if the steam ejector is used as described above. If a steam ejector is used, compared to the case of using a steam compressor (heat pump) such as a Lufthansa steam compressor, a turbo steam compressor, a screw-type steam compressor, an impeller-type steam compressor, etc., the operating cost increases, but it can Reduce initial costs. Depending on the processing capacity of the device, the unit price of electricity, industrial water, etc., it may be advantageous to use a steam ejector.

(4) In the above embodiment, two evaporators, namely, the upstream side evaporator 3A and the downstream side evaporator 3B, are used as the evaporator section 3, that is, a structure where two divided evaporator sections are provided in total. However, three or more divided evaporators may be provided. Even if the number of divided evaporators is three or more, the more upstream the divided evaporator is, the smaller the temperature difference is raised by the temperature increasing means, which can achieve energy saving.

In addition, when the two divided evaporators are formed by dividing one evaporator, the number of divisions is increased, and the divided evaporators formed by the division may be three or more.

(5) In the above embodiment, a concentrating tower 5 is installed at the rear stage of the evaporating section 3, and the ammonia-containing vapor discharged from the distillation tower 2 can be recovered by two stages of concentration in the evaporating section 3 and the concentrating tower 5. However, in the present invention, the concentration tower 5 can also be omitted.

In addition, in the above-mentioned embodiment, it is configured to include a first absorption tower 6 that allows ammonia-containing vapor from the concentration tower 5 to absorb moisture to produce a predetermined concentration of recovered ammonia water, and to prevent uncondensed ammonia in the first absorption tower. The second absorption tower 7 in which the vapor is discharged to the outside, for example, instead of the first absorption tower 6 and the second absorption tower 7, a catalyst decomposition device may be installed to decompose and remove ammonia using a catalyst.

In other words, in the heterogeneous substance separation device of the present invention, the heterogeneous substance such as ammonia separated from the original solution can be treated anyway after the treatment operation from the supply of the original solution from outside the system to the heat exchange of the evaporator. For example, it can be recycled like the above-mentioned embodiment, or it can be decomposed and removed. [Industrial Utilization]

The present invention can be applied to a separation device and a separation method for separating foreign substances such as low boiling point substances from a raw liquid composed of two or more substances, the raw liquid being waste water containing low boiling substances such as ammonia.

1: Ammonia recovery device (separation device for heterogeneous substances) 3: Evaporation part 3A: Upstream side evaporator (divided evaporator) 3B: Downstream side evaporator (divided evaporator) 18: Compression device (heating means) 18A: Upstream side vapor compressor (heating means) 18B: Downstream side vapor compressor (heating means)

[Fig. 1] is an overall configuration diagram of the ammonia recovery device of the embodiment. [Fig. 2] is an enlarged view of the vicinity of the evaporator of the ammonia recovery device of Fig. 1. [Fig. [Fig. 3] is an enlarged view of the vicinity of the concentration tower of the ammonia recovery device of Fig. 1. [Fig. [Figure 4] is a gas-liquid equilibrium curve diagram of a mixture composed of water and ammonia under atmospheric pressure, which is a curve diagram of ammonia concentration from 0 to 100%. [Figure 5] is a gas-liquid equilibrium curve diagram of a mixture of water and ammonia under atmospheric pressure, which is a curve diagram of 0-50% ammonia concentration. [Fig. 6] It is an enlarged view of a modification example for comparison and comparison in which the evaporator is composed of a single evaporator. [Fig. 7] It is an enlarged view of a modified example formed by dividing one evaporator into a plurality of divided evaporators. [Fig. 8] is a plan view of the evaporator of Fig. 7. [Fig. [Fig. 9] is an enlarged view of a modified example of using a steam injector as a heating means.

1: Ammonia recovery device (separation device for heterogeneous substances)

2: distillation tower

3: Evaporation part

3A: Upstream side evaporator (divided evaporator)

3B: Downstream side evaporator (divided evaporator)

5: Concentration tower

6: The first absorption tower

7: The second absorption tower

10: Steam ejector

10a: Vapor suction side

11: Heat recovery tank

12A, 12B: Horizontal tube type evaporation tank

13A, 13B: sprayer

17A, 17B: Retention Department

18: Compression device (heating means)

18A: Upstream side vapor compressor (heating means)

18B: Downstream side vapor compressor (heating means)

H1~H5: Heat exchanger

L1: Stock solution supply pipe

L2A, L2B: tube

L3: Steam supply pipe for heating

L4: Tube

L5: Steam supply pipe

L6: Steam reuse pipe

L7: discharge pipe

L8: Water supply pipe

L10: Steam supply pipe

L11, L12, L15~L18: tube

L20, L23: spray tube

L21, L24: Tube

L22, L25: branch pipe

L30, L32, L33: tube

L31: Spray tube

L34: Exhaust pipe

L40: Cooling water supply pipe

L41: Tube

P1: Pump for treated water discharge

P2A, P2B, P4, P5, P6: circulation pump

P3: Condensate pump

V1, V2: control valve

Claims (9)

A separation device for dissimilar substances is to generate a first vapor from a raw liquid composed of two or more substances and introduce it to an evaporator, exchange the heat between the first vapor and the liquid, and thereby partially condense the first vapor. The liquid is concentrated, the liquid is evaporated and discharged as the second vapor, and the second vapor is heated by a temperature increasing means to be used as a heating vapor for the generation of the first vapor, characterized in that: The evaporator has a configuration in which at least two divided evaporators are connected in series along the flow direction of the first vapor, and the temperature rise means are provided in the two divided evaporators, respectively, The temperature rise means of the split evaporator provided on the upstream side in the direction of flow of the first vapor among the two split evaporators has a temperature difference when the temperature of the second vapor is raised is greater than that of the split evaporator provided on the downstream side. The aforementioned heating means is small. The separation device for dissimilar substances as described in claim 1, wherein: The aforementioned two divided evaporators are formed by dividing one evaporator. The separation device for dissimilar substances as described in claim 1, wherein: As a means for generating the first vapor from the raw liquid, a distillation column is provided, In this distillation column, the raw liquid is brought into contact with steam for heating, and one or more foreign substances are separated from the raw liquid and vaporized to be discharged from the top of the tower as the first vapor containing the one or more foreign substances. , And store the treatment liquid at the bottom of the tower after removing the above-mentioned one or more foreign substances from the above-mentioned original liquid. The separation device for dissimilar substances as described in claim 2, wherein: As a means for generating the first vapor from the raw liquid, a distillation column is provided, In this distillation column, the raw liquid is brought into contact with steam for heating, and one or more foreign substances are separated from the raw liquid and vaporized to be discharged from the top of the tower as the first vapor containing the one or more foreign substances. , And store the treatment liquid at the bottom of the tower after removing the above-mentioned one or more foreign substances from the above-mentioned original liquid. The separation device for dissimilar substances according to any one of claims 1 to 4, wherein: The temperature raising means provided in the split evaporating part on the upstream side is smaller than the temperature raising means provided in the split evaporating part on the downstream side. The separation device for dissimilar substances according to any one of claims 1 to 4, wherein: The aforementioned stock solution is composed of water and a low boiling point substance. The separation device for dissimilar substances according to any one of claims 1 to 4, wherein: The aforementioned heating means includes a heat pump and/or a steam ejector. A separation device for dissimilar substances is equipped with a distillation tower, an evaporator, and a compression device. The distillation tower is to contact the raw liquid containing low-boiling substances with heating water vapor to separate the low-boiling substances from the raw liquid and vaporize it. The vapor containing low-boiling substances is discharged from the top of the tower, and the treated water after the low-boiling substances has been removed from the raw liquid is stored at the bottom of the tower; the aforementioned evaporation part is for the low-boiling substances discharged from the top of the distillation tower The steam and water exchange heat, so that the vapor containing the low boiling point substance is partially condensed, and the vapor containing the low boiling point substance is concentrated, and the water is evaporated and discharged as water vapor; the compression device is from the aforementioned The water vapor discharged from the evaporator is compressed and heated, and the compressed and heated water vapor is introduced into the aforementioned distillation tower and used as heating water vapor used in the distillation tower. It is characterized in that: The evaporator has a configuration in which at least two divided evaporators are connected in series along the flow direction of the vapor containing the low boiling point substance, and the compression device is provided in each of the two divided evaporators, The compression device of the divided evaporator installed on the upstream side in the flow direction of the vapor containing the low-boiling substance in the two divided evaporators has a higher temperature difference when the water vapor is compressed and heated than when it is installed on the downstream side The aforementioned compression device of the divided evaporator is small. A method for separating dissimilar substances is to generate a first vapor from a raw liquid composed of two or more substances and introduce it to an evaporator, and exchange heat between the first vapor and the liquid, thereby allowing the first vapor to be partially condensed. The liquid is concentrated, the liquid is evaporated and discharged as the second vapor, and the second vapor is heated by a temperature increasing means to be used as a heating vapor for the generation of the first vapor, characterized in that: The evaporator is configured by connecting at least two divided evaporators in series along the flow direction of the first vapor, and the temperature increasing means is provided in each of the two divided evaporators, Among the two divided evaporators, the temperature difference of the divided evaporator provided on the upstream side in the flow direction of the first vapor is greater than the temperature difference of the divided evaporator provided on the downstream side when the second vapor is raised. The aforementioned heating means is small.

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