Distillation device, method of concentrating heavy water, and method of producing concentrated heavy water

Abstract

To provide a distillation device that can cope with a significant increase in the flow rate of flowing fluid, and allows for a compact size of a distillation tower, and a method of concentrating heavy water and a method of producing concentrated heavy water.SOLUTION: A distillation device comprises: one or more distillation towers containing a regulated filled object formed of a metal material in the tower(s) ; one or more evaporators; one or more condensers; a channel-type liquid distributor that is arranged above the regulated filled object in a vertical direction for distributing liquid to the regulated filled object, the liquid distributor being formed of two distributors including an upper liquid distributor arranged on an upper side and a lower liquid distributor arranged on a lower side; a pipe that feeds liquid to the upper liquid distributor; a pipe that feeds liquid to the lower liquid distributor; and one or more valves arranged on the pipe that feeds liquid to the upper liquid distributor.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a distillation apparatus, a method for concentrating heavy water, and a method for producing concentrated heavy water. [Background technology]

[0002] FIG. 7 is a system diagram showing an example of the configuration of a conventional distillation apparatus. As shown in FIG. 7, the conventional distillation apparatus 3 includes a distillation column D having metallic structured packing in the column to increase the contact area between the gas and liquid, a condenser C located above the distillation column D, which liquefies the gas flowing from the top of the distillation column D and returns it as a reflux liquid, and a reboiler R located below the distillation column D, which gasifies the liquid at the bottom of the distillation column D and returns it as an ascending gas. In the distillation apparatus 3, the raw material liquid F is supplied to the distillation column D, and the high boiling point components are concentrated in the liquid side and the low boiling point components are concentrated in the gas side by contact between the gas and liquid in the distillation column D. In the distillation apparatus 3, a part of the liquid at the bottom of the distillation column D is taken out as a product P, and a part of the liquid liquefied by the condenser C is discharged to the outside of the system as a waste liquid W1.

[0003] It is known that aqueous liquids with high surface tension have poor wettability on metal surfaces. When distilling aqueous liquids with high surface tension, for example, when operating a distillation column D having metallic structured packing as shown in FIG. 7, the "Height Equivalent to a Theoretical Plate (HETP)" which is an index of distillation performance (performance of packing) becomes 200 mm or more, and the distillation performance deteriorates (Non-Patent Document 1). This is presumed to be because the liquid has poor dispersibility on the structured packing surface compared to liquids with low surface tension, and the liquid causes drift, which reduces the contact area between gas and liquid, making it difficult to proceed with distillation separation.

[0004] On the other hand, it is known that when starting up a distillation column using metallic mesh-like structured packing, applying a load higher than the normal operating load improves the liquid dispersion of the structured packing and improves the distillation performance.

[0005] Generally, a distillation tower is equipped with a liquid distributor (also called a "distributor") to distribute liquid evenly over the cross section of the structured packing (except for distillation towers with small tower diameters where a single drop is sufficient). A liquid distributor has a structure in which liquid poured from above flows down through distribution holes (also called "orifices") provided on the bottom surface using the liquid head. They are broadly divided into tubular types that combine pipes and channel types that combine troughs (Non-Patent Document 2). Both types have the function of distributing liquid at an equal flow rate over the surface of the structured packing by utilizing the uniform liquid head applied to each distribution hole. [Prior art documents] [Non-patent literature]

[0006] [Non-Patent Document 1] Eiichi Hirose, Kazuo Watari, "Structured Packing and Liquid Disperser with Low Liquid Loading in Systems with High Surface Tension", Separation Technology, 2014, Vol. 44, No. 1, pp. 38-42 [Non-Patent Document 2] Separation Technology Society (ed.), "Separation Technology Series 2: Revised New Edition Tray Packing", Separation Technology Society, 2005, pp.68-71 Summary of the Invention [Problem to be solved by the invention]

[0007] The flow rate Q from the dispersion hole provided on the bottom surface of a conventional liquid distributor can be calculated from the orifice discharge coefficient equation as follows:

number

[0008] An object of the present invention is to provide a distillation apparatus that can accommodate a significant increase in the inflow flow rate while suppressing an increase in the size of the distillation column, a method for concentrating heavy water, and a method for producing concentrated heavy water. [Means for solving the problem]

[0009] [1] One or more distillation columns having structured packing made of a metal material in the column, and concentrating high boiling point components in the liquid side and low boiling point components in the gas side by contact between gas and liquid in the column; one or more evaporators for vaporizing at least a portion of the descending liquid of the distillation column and introducing the portion of the vapor into the distillation column as an ascending gas; one or more condensers for liquefying at least a portion of the ascending gas in the distillation column and introducing a portion of the liquefied gas into the distillation column as reflux; a channel-type liquid distributor disposed vertically above the structured packing for distributing liquid into the structured packing, the channel-type liquid distributor comprising an upper liquid distributor located at the top and a lower liquid distributor located at the bottom, the upper liquid distributor and the lower liquid distributor each storing liquid therein to form a liquid depth, and each having a function of uniformly dispersing the liquid from distribution holes provided in the bottom surface by a liquid head of the stored liquid; A pipe for delivering the liquid to the upper liquid distributor; A pipe for delivering the liquid to the lower liquid distributor; one or more valves located in the piping that delivers the liquid to the upper liquid distributor; A distillation apparatus comprising: [2] The distillation apparatus according to [1], wherein the total opening area of ​​the dispersion holes of the upper liquid distributor is larger than the total opening area of ​​the dispersion holes of the lower liquid distributor. [3] The distillation apparatus according to [1] or [2], wherein the hole diameter of the dispersion hole of the upper liquid distributor is larger than the hole diameter of the dispersion hole of the lower liquid distributor. [4] A distillation apparatus according to any one of [1] to [3], wherein the dispersion holes of the upper liquid distributor are positioned between the arm channels of the lower liquid distributor so that the falling liquid from the upper liquid distributor does not collide with the arm channels of the lower liquid distributor. [5] A method for concentrating heavy water, comprising a step of distilling a liquid containing heavy water using the distillation apparatus according to any one of [1] to [4], A method for concentrating heavy water, comprising: sending the liquid containing heavy water to the upper liquid distributor before the liquid containing heavy water overflows from the lower liquid distributor. [6] A method for producing concentrated heavy water, comprising a step of distilling a liquid containing heavy water using the distillation apparatus according to any one of [1] to [4], A method for producing concentrated heavy water, comprising: sending the liquid containing heavy water to the upper liquid distributor before the liquid containing heavy water overflows from the lower liquid distributor. Effect of the Invention

[0010] According to the present invention, it is possible to provide a distillation apparatus and a method for concentrating heavy water that can accommodate a significant increase in the inflow liquid flow rate while suppressing an increase in the size of the distillation column. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a system diagram showing an example of the configuration of a distillation apparatus according to one embodiment of the present invention. [Figure 2A] FIG. 2A is a schematic diagram showing an example of the configuration of the lower liquid distributor. [Figure 2B] FIG. 2B is a schematic diagram showing a configuration example of the upper liquid distributor. [Diagram 3] FIG. 3 is a schematic diagram showing an example of the arrangement of the dispersion holes of the liquid distributor shown in FIGS. 2A and 2B. [Figure 4A] FIG. 4A is a schematic diagram showing another configuration example of the lower liquid distributor. [Figure 4B] FIG. 4B is a schematic diagram showing another configuration example of the upper liquid distributor. [Diagram 5] FIG. 5 is a schematic diagram showing an example of the arrangement of the dispersion holes of the liquid distributor shown in FIGS. 4A and 4B. [Figure 6] FIG. 6 is a system diagram showing another example of the configuration of a distillation apparatus according to one embodiment of the present invention. [Figure 7] FIG. 7 is a system diagram showing an example of the configuration of a conventional distillation apparatus. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, a distillation apparatus, a method for concentrating heavy water, and a method for producing concentrated heavy water, which are embodiments of the present invention, will be described in detail with reference to the drawings as appropriate. Note that the drawings used in the following description may show characteristic parts in an enlarged scale for the sake of convenience in order to make the characteristics easier to understand, and the dimensional ratios of each component may not necessarily be the same as in reality.

[0013] The meanings and definitions of terms used in this specification are as follows: A numerical range expressed by "to" means that the numerical values ​​before and after the "to" are the lower and upper limits of the numerical range. The upper part of the distillation column (also called the upper part of the distillation column) refers to the area vertically upward from the center of the distillation column. The lower part of the distillation column (also called the lower part of the distillation column) refers to the area vertically downward from the center of the distillation column.

[0014] [Distillation apparatus] The configuration of a distillation apparatus according to one embodiment of the present invention will be described below. Here, Fig. 1 is a system diagram showing the configuration of a distillation apparatus 1 according to one embodiment of the present invention. As shown in FIG. 1, the distillation apparatus 1 of this embodiment is roughly configured to include a distillation column D, a reboiler (evaporator) R, a condenser (condenser) C, a first structured packing 100, a second structured packing 200, a first liquid distributor 10 consisting of a first lower liquid distributor 11 and a first upper liquid distributor 12, a second liquid distributor 20 consisting of a second lower liquid distributor 21 and a second upper liquid distributor 22, a collector 13, and pipes L1, L2, L3, L4, L5, L11, L12, L13, L21, and L22.

[0015] Distillation column D is a column arranged so that the axial direction is vertical, and high boiling point components are concentrated in the liquid side and low boiling point components are concentrated in the gas side by contact between gas and liquid in the column. Here, the structured packing 100 (200) increases the contact area between the gas and liquid.

[0016] The structured packing 100 (200) is not particularly limited as long as it is made of a metal material, and can be appropriately selected depending on the components to be distilled. When distilling a liquid with a high surface tension, it is preferable to use a metallic mesh-shaped structured packing as the structured packing.

[0017] A pipe L1 is connected to the center of the distillation column D for introducing the raw liquid F into the distillation column D. The pipe L is connected to pipes L11, L12, and L13 described later. A valve V1 for adjusting the flow rate is disposed in the pipe L1. The valve V1 is a valve that adjusts the flow rate of the liquid. It is preferable that the valve V1 can be adjusted to any opening degree from a fully closed state (opening degree 0%) to a fully open state (opening degree 100%). The same applies to valves V12 and V22 described later.

[0018] Pipe L2 is located at the top of distillation column D. Here, the base end of pipe L2 is connected to the top of distillation column D, and the tip of pipe L2 is connected to the upper part of distillation column D. In addition, a condenser C is disposed in pipe L2. In addition, pipe L2 branches into pipe L3 on the secondary side of condenser C.

[0019] The condenser C is located in the pipe L2, and liquefies at least a part of the ascending gas flowing from the top of the distillation column D, and introduces a part of the liquefied gas as a reflux liquid into the upper part of the distillation column D. As a cooling source for the condenser C, for example, a liquefied gas or water can be used.

[0020] Pipe L3 is a pipe for discharging liquid that branches off from pipe L2 on the secondary side of condenser C. A portion of the liquid liquefied by condenser C is introduced as a reflux liquid into the upper part of distillation column D via pipe L2, and the remainder is discharged to the outside of the system as waste liquid W1 via pipe L3.

[0021] Pipe L4 is located at the bottom of distillation column D. Here, the base end of pipe L4 is connected to the bottom of distillation column D, and the tip of pipe L4 is connected to the lower part of distillation column D. A reboiler (evaporator) R is disposed in pipe L4. Furthermore, pipe L4 branches off from pipe (product discharge pipe) L5 ​​on the primary side of reboiler R.

[0022] The pipe L5 is a liquid discharge pipe branched off from the pipe L4. That is, the pipe L5 is a pipe for extracting, as a product P, a portion of the liquid discharged through the pipe L4 from the liquid stored in the bottom of the distillation column D.

[0023] The reboiler (evaporator) R is located in the pipe L4, and vaporizes at least a part of the descending liquid flowing from the bottom of the distillation column D, and introduces a part of it as an ascending gas into the lower part of the distillation column D. That is, the reboiler R has a container for storing the liquid and a heat source for heating the liquid. As the heat source of the reboiler R, for example, the same type of gas as the cooling source of the condenser C, water, a heater, etc. can be used.

[0024] The liquid distributor 10 (20) is disposed above the structured packing 100 (200) in order to distribute the reflux liquid from the condenser C evenly throughout the structured packing 100 (200). The distillation column D shown in Fig. 1 is equipped with two sets of a liquid distributor and structured packing. That is, the distillation column D is equipped with a set of a liquid distributor 10 and structured packing 100 and a set of a liquid distributor 20 and structured packing 200. The liquid distributor 10 (20) includes a lower liquid distributor 11 (21) having a function of uniformly distributing liquid in the structured packing during rated operation of the distillation apparatus 1, and an upper liquid distributor 12 (22) above the lower liquid distributor 11 (21) for distributing an amount of liquid in excess of the rated amount, both located above the structured packing 100 (200). A flow rate adjusting valve V12 (V22) is disposed in a pipe L12 (L22) for supplying liquid to the upper liquid distributor 12 (22).

[0025] With these configurations, when the liquid flow rate is rated, the entire amount of return liquid from condenser C is supplied to the second lower liquid distributor 21 through pipe L2. However, if the flow rate increases and there is a risk of overflowing the second lower liquid distributor 21, the valve V22 can be opened to supply the return liquid from condenser C to the second upper liquid distributor 22, thereby preventing the second lower liquid distributor 21 from overflowing. A similar configuration can be applied to an intermediate distributor for redistributing the liquid bias occurring in the second structured packing 200. The descending liquid from the second structured packing 200 is collected by the collector 13 installed at the bottom of the second structured packing 200. The descending liquid is supplied to the first lower liquid distributor 11 and the first upper liquid distributor 12 through the pipes L11 and L12, respectively. A flow rate control valve V12 is disposed in the pipe L12 connected to the first upper liquid distributor 12, and when the inflow liquid flow rate from the collector 13 is likely to overflow from the first lower liquid distributor 11, the valve V12 is opened to supply the liquid to the first upper liquid distributor 12. This makes it possible to avoid overflow at the first lower liquid distributor 11 even in the intermediate distributor.

[0026] Also, the raw liquid F can be supplied to the first lower liquid distributor 11 and the first upper liquid distributor 12 via a pipe L1.

[0027] The flow rates flowing through the first lower liquid distributor 11 and the second lower liquid distributor 21 can be determined by flow meters (not shown) installed in the pipes L11 and L21 connected to them, respectively, or can be indirectly determined by calculating the amount of reflux liquid from the heat exchange amount of condenser C.

[0028] Next, the configurations of the lower liquid distributor and the upper liquid distributor are shown in Figures 2A and 2B. The lower liquid distributor 11 (21) and the upper liquid distributor 12 (22) are respectively provided with a pipe L11 (L21) and a pipe L12 (L22), and have a main channel 15 (18) that receives liquid and an arm channel 16 (19) branched off from the main channel 15 (18). A plurality of dispersion holes 14 (17) for dripping liquid are provided on the bottom surface of the arm channel 16 (19). In addition, a buffer material or a filler may be introduced into the main channel 15 (18) to uniformize the dynamic pressure distribution when the liquid is introduced.

[0029] Both the lower liquid distributor 11 (21) and the upper liquid distributor 12 (22) have a plurality of dispersion holes 14 (17) on the bottom side of the arm channel so that the liquid is uniformly dispersed in the structured packing, but the dispersion holes 17 of the upper liquid distributor 12 (22) have a larger hole diameter than the dispersion holes 14 of the lower liquid distributor 11 (21), or the total opening area of ​​the dispersion holes 17 is larger than the total opening area of ​​the dispersion holes 14. As a result, even if the liquid flow rate is such that it overflows the lower liquid distributor 11 (21), it is possible to maintain dispersion performance without the risk of overflowing in the upper liquid distributor 12 (22).

[0030] In addition, the dispersion holes 17 of the upper liquid distributor 12 (22) are arranged at a position where the liquid does not hit the arm channel 16 of the lower liquid distributor 11 (21) when it falls. Figure 3 shows an example of the arrangement of the dispersion holes 14 and 17 when the lower liquid distributor 11 (21) and the upper liquid distributor 12 (22) are seen from a viewpoint looking up from the structured packing side. This makes it possible to prevent the liquid flowing down from the upper liquid distributor 12 (22) from colliding with the lower liquid distributor 11 (21) and changing the drip position, or entering the lower liquid distributor 11 (21).

[0031] Other embodiments of the upper liquid distributor 12 (22) and the lower liquid distributor 11 (21) are shown in Figures 4A, 4B, and 5. The explanations for Figures 4A, 4B, and 5 are the same as those for Figures 2A, 2B, and 3 above.

[0032] Fig. 6 is a system diagram showing another example of a distillation apparatus according to one embodiment of the present invention. As shown in Fig. 6, distillation apparatus 2 differs in configuration from distillation apparatus 1 shown in Fig. 1 in that it includes distillation columns D1 to D3 connected in series instead of distillation column D. Other configurations of distillation apparatus 2 are the same as those of distillation apparatus 1, so the same reference numerals are used and the description will be omitted.

[0033] As shown in FIG. 2, a pipe L2 is connected to the upper part of the distillation column D1. A pipe L1 for introducing a raw liquid F into the distillation column D1 is connected to the center of the distillation column D1.

[0034] Pipes L6 and L7 are located between distillation column D1 and distillation column D2. The base end of the pipe L6 is connected to the bottom of the distillation column D1, and the tip end is connected to the top side of the distillation column D2. This allows the pipe L6 to supply a portion of the liquid stored at the bottom of the distillation column D1 as a descending liquid to a position near the top of the distillation column D2. The base end of the pipe L7 is connected to the top of the distillation column D2, and the tip is connected to the bottom side of the distillation column D1. This allows the pipe L7 to supply a portion of the gas stored at the top of the distillation column D2 as an ascending gas to a position near the bottom of the distillation column D1.

[0035] Pipes L8 and L9 are located between distillation column D2 and distillation column D3. The base end of the pipe L8 is connected to the bottom of the distillation column D2, and the tip end is connected to the top of the distillation column D3. This allows the pipe L8 to supply a portion of the liquid stored at the bottom of the distillation column D2 as a descending liquid to a position near the top of the distillation column D3. The base end of the pipe L9 is connected to the top of the distillation column D3, and the tip is connected to the bottom side of the distillation column D2. This allows the pipe L9 to supply a portion of the gas stored at the top of the distillation column D3 as an ascending gas to a position near the bottom of the distillation column D2.

[0036] A pipe L4 is connected to the bottom of the distillation column D3. In addition, the pipe L4 has a branch point with the pipe L5 and a reboiler R located therein.

[0037] [Method for concentrating heavy water and method for producing concentrated heavy water] The method for concentrating heavy water and the method for producing concentrated heavy water according to one embodiment of the present invention include a step of distilling a liquid containing heavy water using the above-mentioned distillation apparatus, and is characterized in that the liquid containing heavy water is supplied to the upper liquid distributor 12 (22) before the liquid containing heavy water overflows from the lower liquid distributor 11 (21). This makes it possible to uniformly distribute the liquid among the packings without causing liquid bias due to overflow from the liquid distributor. As a result, the distillation performance can be improved. The liquid containing heavy water is, for example, pure water.

[0038] In the above-described embodiments of the distillation apparatuses 1 and 2, a case has been described as an example in which deuterium is concentrated by distilling a liquid containing heavy water as a raw material liquid, such as pure water, but the present invention is not limited to this.

[0039] [Effects] In the distillation apparatus of the present invention, the liquid can be uniformly dispersed on the packing without causing liquid drift due to overflow from the liquid distributor. Therefore, in the distillation of a liquid having a high surface tension, the liquid can be uniformly dispersed without liquid drift during high load operation, improving the dispersibility of the liquid on the structured packing and improving the distillation performance. EXAMPLES

[0040] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the examples described below.

[0041] An example will be described for heavy water (deuterium concentration 50%), which is a substance with high surface tension. In this example, a distillation apparatus shown in FIG. 1 was used. In the distillation of heavy water, due to the difference in vapor pressure ratio between light water and heavy water, deuterium is concentrated at the bottom of the distillation column, and the deuterium concentration decreases at the top. Here, the column above the feed introduction position is called the stripping section, and the column below is called the enrichment section.

[0042] Distillation column D was a distillation column with a column diameter of 0.4 m having a stripping section and a concentration section with a packing length of 3 m, and employed metallic mesh-type structured packing as the structured packing. As the metallic mesh structured packing, Laboratory packing, BX packing, or CY packing manufactured by Sulzer ChemTech was used. A multi-tube heat exchanger was installed on the top of the tower as a condenser C, and cooling water from a chiller was used as a cooling source. On the other hand, a steam boiler composed of a multi-tube heat exchanger was used on the bottom of the tower as a reboiler R for generating ascending gas in the distillation tower. In this example, a reboiler installed independently of the distillation tower was used, but a reboiler integrated into the lower part of the tower may also be used. The reflux liquid from the condenser C is introduced into the second lower liquid distributor 21 installed at the top of the tower via a pipe L21 branched off from the pipe L2. The reflux liquid from the condenser C is introduced into the second upper liquid distributor 22 via a valve V22 through a pipe L22 branched off from the pipe L2. The second upper liquid distributor 22 was installed above the second lower liquid distributor 21 with a space of about 50 mm provided. The structure of each liquid distributor will be described later.

[0043] Next, at the bottom of the stripping section, the descending liquid is collected by a collector 13 in order to redistribute the drift of the descending liquid occurring in the second structured packing 200, and is introduced into the first lower liquid distributor 11 through a pipe L11. As with the second liquid distributor 20 at the top of the column, the descending liquid is introduced into the first upper liquid distributor 12 through a pipe L12 branching off from the pipe L11 and a valve V12 arranged midway through the pipe L12. The first upper liquid distributor 12 was installed with a space of about 50 mm provided from the first lower liquid distributor 11.

[0044] The feed pipe L1 for the raw material heavy water was connected to pipes L11 and L12 via a valve V1. The area around the reboiler below the rectifying section was constructed according to the conventional distillation column design.

[0045] The resulting product heavy water is collected from pipe L5 (product port) branched off from the tower bottom pipe connected to the reboiler R, and wastewater with reduced heavy water concentration is discharged from pipe L3 (recovery port).

[0046] Next, the upper liquid distributor and the lower liquid distributor used in this embodiment will be described. Both liquid distributors are based on a trough-type liquid distributor made of SUS steel, and have the configurations shown in Figures 2A, 2B, and 3. The outer diameter size of the first lower liquid distributor 11 and the second lower liquid distributor 21 was W280mm x H160mm x D280mm, the hole diameter of the dispersion hole was 1.8mm, the number of dispersion holes was 20, the number of arm channels was 10, the arm channel width was 20mm, and the distance between the arm channels was 45mm. The outer diameter size of the first upper liquid distributor 12 and the second upper liquid distributor 22 was W232mm x H180mm x D232mm, the hole diameter of the dispersion hole was 6.0mm, the number of dispersion holes was 10, the number of arm channels was 8, the arm channel width was 40mm, and the distance between the arm channels was 24mm.

[0047] At this time, the dispersion holes 14 of the lower liquid distributor were arranged on the bottom side so as to be as evenly spaced as possible so that the liquid would be uniformly dispersed on the packing. Also, the dispersion holes 17 of the upper liquid distributor were arranged on the bottom side so as to be as evenly spaced as possible so that the liquid would not come in contact with the arms of the lower liquid distributor.

[0048] It is known that the vapor pressure ratio between heavy water and light water increases as the pressure decreases, and the operating pressure of distillation column D was set to 20 kPa absolute. The pressure was controlled and kept constant by adjusting the flow rate and temperature of the cooling water in condenser C. The steam load of distillation column D was controlled by the steam flow rate and temperature in reboiler R, and the rated operating value was Fs = 1.0 m / s (kg / m 3 ) 0.5 (Here, Fs stands for F factor.) When total reflux operation was performed at this rated value, the ascending gas generated in reboiler R was totally condensed in condenser C after passing through the tower, and the reflux liquid amount was about 3 L / min. On the other hand, as a reference example, when the upper liquid distributor 12 (22) was not used and operation was performed at Fs=1.5 in accordance with the distillation separation startup method using high load operation, the reflux liquid amount was about 4.5 L / min.

[0049] In this embodiment, the amount of reflux liquid was set to 18 L / min in order to improve the dispersion of the liquid on the packing surface by further increasing the liquid flow rate. During rated operation with Fs = 1.0, valves V12 and V22 were closed, and all liquid was made to flow to the lower liquid distributor 11 (21). At this time, the liquid depth inside the lower liquid distributor was calculated to be 100 mm, and all liquid dripping onto the packing was performed from the dispersion holes of the lower liquid distributor.

[0050] Next, under high load operating conditions with a reflux liquid amount of 18 L / min, if liquid is flowed only through the lower liquid distributor 11 (21), the internal liquid depth becomes 3600 mm, resulting in overflow. Therefore, valves V12 and V22 are opened to flow liquid through the first upper liquid distributor 12 and the second upper liquid distributor 22. At this time, in order to ensure that liquid does not overflow from the first lower liquid distributor 11 and the second lower liquid distributor 21, it is desirable to install a liquid flow meter in either the pipe L11 or the pipe L21, or in the pipe L12 and the pipe L22. Here, clamp-type ultrasonic flow meters are installed in the pipes L11 and L21.

[0051] As a result, no overflow from the lower liquid distributor occurs, and the liquid is poured onto the packing from both the dispersion holes of the upper liquid distributor and the lower liquid distributor. This makes it possible to distribute the liquid evenly to the packing without causing liquid unevenness even during high load operation.

[0052] The results of distillation performance after heavy water distillation after high-load operation using the configuration of the present invention and after high-load operation using only one trough-type liquid distributor of the conventional technology (i.e., when overflow occurred) are shown in Table 1. HETP is used as an index of distillation performance, and is calculated from the heavy water concentration of water collected from pipe L5 (product port) and pipe L3 (discharge port). HETP represents the packing height equivalent to one theoretical plate, and the smaller the value, the better the separation performance.

[0053] [Table 1]

[0054] The HETP after high load operation in the distillation apparatus of the reference example was 180 mm, which was better than the performance when started only at rated operation, but the performance was further improved in the distillation apparatus of the embodiment of the present invention, reaching a HETP of 100 mm. [Explanation of symbols]

[0055] 1,2,3...Distillation apparatus 100,200…regular filling 11,21…Lower liquid distributor 12,22…Upper liquid distributor 13…Collector 14,17…dispersion pores 15,18…Main channel 16,19…Arm channel C...Condenser D, D1, D2, D3...Distillation tower F…raw material liquid L1,L2,L3,L3,L5,L6,L7,L8,L9,L11,L12,L13,L21,L22...Piping P…Product R…Reboiler (evaporator) W1…Drainage

Claims

1. One or more distillation columns having structured packing made of a metal material therein, and concentrating high boiling point components into a liquid side and low boiling point components into a gas side by contact between gas and liquid in the column; one or more evaporators for vaporizing at least a portion of the descending liquid of the distillation column and introducing the portion of the vapor into the distillation column as an ascending gas; one or more condensers for liquefying at least a portion of the ascending gas in the distillation column and introducing a portion of the liquefied gas into the distillation column as reflux; a channel-type liquid distributor disposed vertically above the structured packing for distributing a liquid into the structured packing, the channel-type liquid distributor comprising an upper liquid distributor located at the top and a lower liquid distributor located at the bottom, the upper liquid distributor and the lower liquid distributor each storing liquid therein to form a liquid depth, and each having a function of uniformly dispersing the liquid from distribution holes provided in the bottom surface by a liquid head of the stored liquid; A pipe for delivering the liquid to the upper liquid distributor; A pipe for delivering the liquid to the lower liquid distributor; one or more valves located in the piping that delivers the liquid to the upper liquid distributor; A distillation apparatus comprising:

2. 2. The distillation apparatus according to claim 1, wherein the total opening area of ​​the dispersion holes of the upper liquid distributor is greater than the total opening area of ​​the dispersion holes of the lower liquid distributor.

3. 2. The distillation apparatus according to claim 1, wherein the hole size of the dispersion holes in the upper liquid distributor is larger than the hole size of the dispersion holes in the lower liquid distributor.

4. 2. The distillation apparatus according to claim 1, wherein the dispersion holes of the upper liquid distributor are located between the arm channels of the lower liquid distributor so that the falling liquid from the upper liquid distributor does not impinge on the arm channels of the lower liquid distributor.

5. A method for concentrating heavy water, comprising a step of distilling a liquid containing heavy water using the distillation apparatus according to any one of claims 1 to 4, A method for concentrating heavy water, comprising: sending the liquid containing heavy water to the upper liquid distributor before the liquid containing heavy water overflows from the lower liquid distributor.

6. A method for producing concentrated heavy water, comprising a step of distilling a liquid containing heavy water using the distillation apparatus according to any one of claims 1 to 4, A method for producing concentrated heavy water, comprising: sending the liquid containing heavy water to the upper liquid distributor before the liquid containing heavy water overflows from the lower liquid distributor.

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