JP4984133B2 - Concentration method, concentration separation method, concentration recovery method, and regeneration method of guest molecules of inclusion compounds - Google Patents

Description

  The present invention relates to a concentration method, a concentration separation method, a concentration recovery method, and a regeneration method for concentrating a guest molecule in a solution containing a host molecule of the inclusion compound as a solvent and a guest molecule as a solute and having a density different from that of the inclusion compound. About.

  In addition, the meaning or interpretation of the following terms or expressions are as follows.

  (1) “Raw material solution” refers to a solution containing a host molecule of a clathrate compound as a solvent and a guest molecule as a solute. A solution containing a host molecule of the inclusion compound as a solvent and a guest molecule as a solute and in which the inclusion compound is dispersed or suspended is also a “raw material solution”.

  (2) “Clusion compound” means that when a plurality of molecules are combined under appropriate conditions to form a crystal, one molecule (host molecule) forms a cage, tunnel, layer, or network structure. This means a compound having a structure in which another molecule (guest molecule) enters the gap, and includes not only the clathrate compound in a narrow sense to exclude the clathrate hydrate (see Patent Document 1), but also this clathrate hydration. Broadly defined clathrate compounds including products (see Patent Documents 2 and 3) also fall under the “clathrate compound”. Needless to say, this is not the case with ice formed by water solidification.

  The “clathrate compound” includes clathrate hydrate, and the clathrate hydrate includes quasi clathrate hydrate.

  (3) “Heat exchanger” means a heat transfer object having an outer surface that enables heat exchange with a heat source or a heat medium, and whether it is solid, cross-sectional shape, dimensions, material, etc. It doesn't matter. A plate type or a multi-tube type may be used. A heat pipe is also a kind of “heat exchanger”. In the specific description of the present invention, even if the specific description of the present invention is sometimes made using a heat transfer tube having a cavity through which a heat transport medium flows as a “heat exchanger”, the “heat exchanger” Is not intended to be limited to such heat transfer tubes.

  (4) The “outer surface” of the heat exchanger refers to a heat exchange surface (heat transfer surface) of the heat exchanger and a region near the heat exchange surface where the effect of the heat exchange extends.

  (5) “Lower” and “upper” refer to the direction in which gravity works and the opposite direction, respectively.

  (6) “Block” refers to an object having an outer shape as one aggregate, and there is no limitation on the shape as long as it is visually distinguishable from surrounding objects, unless otherwise specified. The internal structure, strength, hardness, viscosity, density, composition, etc. are not limited. The “clumps of clathrate compound” refers to those in which the clathrate compound is repeatedly formed to form a clump and can be recognized as a lump and the naked eye.

  (7) “Slurry” refers to a substance in which solid particles are dispersed or suspended in a liquid or a substance in that state. In order to make solid particles that tend to settle into a suspended state, a surfactant may be added or mechanically stirred. In particular, when a clathrate or a mass thereof is referred to as a “slurry”, the inclusion compound includes a host molecule of the clathrate compound as a solvent and a guest molecule as a solute, regardless of the presence or absence of an interfacial physical agent. The clathrate is dispersed or suspended, or a substance in that state, but is not required until the dispersion or suspension is homogeneous. For example, when a part of the clathrate of the clathrate compound (particularly the part in contact with the solution) is dispersed or suspended in the solution but the rest remains agglomerate in the solution, the dispersion Or what is suspended is a "slurry", and it can be said that it exists in the state coexisting in the said lump of inclusion compound and the said solution.

  (8) “Hydrate formation temperature” refers to an equilibrium temperature at which clathrate hydrate should be generated when the aqueous raw material solution is cooled. Even when the temperature at which the clathrate compound is generated varies depending on the concentration of the guest compound in the raw material aqueous solution, this is referred to as “hydrate formation temperature”. For convenience, the “hydrate formation temperature” may be referred to as “melting point”.

  (9) “Harmonic melting point” means that when clathrate hydrate is produced from the liquid phase of the raw material aqueous solution, the concentration of the guest molecule in the raw material aqueous solution is equal to the concentration of the guest molecule in the clathrate hydrate, The temperature at which the composition of the liquid phase does not change before and after the clathrate hydrate is formed. In the state diagram in which the vertical axis represents the hydrate formation temperature and the horizontal axis represents the concentration of the guest compound in the liquid phase of the raw material aqueous solution, the maximum point is the “harmonic melting point”. The concentration of guest molecules in the raw material aqueous solution that gives a harmonic melting point is referred to as “harmonic melting point concentration”. When clathrate hydrate is produced from a raw material aqueous solution having a concentration lower than the harmonic melting point concentration, the concentration of guest molecules in the raw material aqueous solution decreases as the clathrate hydrate is produced, and the hydrate formation temperature relative to that concentration is reduced. descend.

  (10) A region in which the inclusion ratio of the inclusion compound or the concentration of the guest molecule is relatively high may be referred to as a “high concentration region”, and a region in which the inclusion ratio of the inclusion compound or the concentration of the guest molecule is relatively low Sometimes referred to as a “low density region”. However, it does not mean that all the regions other than the “high concentration region” correspond to the “low concentration region”, and it does not mean that all the regions other than the “low concentration region” correspond to the “high concentration region”.

  The clathrate compound has the property of accumulating thermal energy as latent heat when it is generated and releasing the thermal energy when it is melted. Therefore, research and development for using it as a main component or composition of a heat storage material has been conducted. (Patent Documents 1 to 3).

  Here, when the concentration of guest molecules is relatively high in a specific region of the raw material solution, a particular technical value is recognized. For example, if the guest molecule of the clathrate compound is unevenly distributed in a specific region in the raw material solution, a high concentration region is formed in the specific region, and the concentration of the guest molecule can be relatively increased, it is different from the specific region. Guest molecules can be separated at a high concentration by removing the raw material solution in the region, and guest molecules can be recovered at a high concentration by removing the raw material solution in the high concentration region. It becomes possible to reuse the molecules as the main component or composition of the heat storage material. Furthermore, when a heat exchanger is installed in a specific region of a raw material solution having a relatively high concentration of guest molecules, latent heat storage of the clathrate compound is performed in the specific region, and another method is performed in a region other than the specific region. It is also possible to realize composite heat storage in which heat storage (for example, sensible heat storage utilizing the relatively low concentration of host molecules) is performed.

When trying to realize a state where the concentration of guest molecules in a specific region of the raw material solution is relatively high regardless of the purpose, or when such a state is realized regardless of the result The concentration technique or concentration phenomenon of the guest molecule of the clathrate compound is the basis or premise thereof. One example is an aqueous solution regeneration technique for removing impurities from an aqueous solution of a drug that generates clathrate hydrate (a guest molecule of the clathrate hydrate) (Patent Document 4). In this aqueous solution regeneration technology, a treatment tank comprising a raw material solution containing impurities and a heat exchanger disposed in the raw material solution is prepared, and a cooling heat medium is passed through the heat exchanger to wrap around the heat exchanger. Impurities are removed by generating crystals of the wet hydrate, draining the aqueous solution remaining after the crystals are formed, and then supplying the heating medium to the heat exchanger for inclusion hydration The crystal of the product is melted, the raw material solution from which impurities are removed, and further, the raw material solution is heated and concentrated to obtain a guest molecule precipitate.
JP 2005-41908 A Japanese Patent Publication No.57-35224 Japanese Patent No. 3641362 JP 2002-333168 A

  However, since the heat transfer resistance increases as the clathrate compound is generated around the heat exchanger through which the cooling heat medium flows and the thickness increases, the cooling effect by the cooling heat medium does not reach the aqueous solution. This is because, in the technique described in Patent Document 4, even if the clathrate hydrate crystals are generated around the heat exchanger, the guest molecules remain in the aqueous solution without forming crystals, and are discharged out of the treatment tank together with impurities. It means that it will be. Therefore, the technique described in Patent Document 4 is not yet efficient, although it enables concentration of guest molecules of the inclusion compound. Further, in the above prior art, the relationship between the density difference between the clathrate compound and the raw material solution containing the guest molecule as a solute and the concentration of the clathrate compound is not taken into consideration at all, and technical suggestions are also found. Absent.

  This invention makes it a subject to provide the technique which can concentrate a guest molecule more efficiently from a raw material solution in view of the above situation.

  The method for concentrating a guest molecule of a clathrate compound according to the first aspect of the present invention for solving the above-described problem includes a host molecule of the clathrate compound as a solvent and a guest molecule as a solute, and the density of the clathrate compound and the clathrate compound A first step of generating the inclusion compound on the outer surface of a heat exchanger disposed in a different solution and growing it into a mass, and melting a part of the mass from the side of the outer surface, By repeating the second step of detaching the unmelted portion of the massive body from the outer surface, the first step and the second step at least once, the undissolved portion according to the density difference between the inclusion compound and the solution is obtained. And a third step in which the melting part is unevenly distributed in a specific region in the solution, and the concentration of the guest molecules in the specific region is relatively increased.

  The method for concentrating a guest molecule of an inclusion compound according to the second aspect of the present invention is the concentration method according to the first aspect, wherein the first step accumulates thermal energy due to the latent heat of the inclusion compound. It is a process, and the second process is a process of taking out heat energy from a part of the lump by the heat exchanger.

  The method for concentrating a guest molecule of an inclusion compound according to the third aspect of the present invention is the concentration method according to the second aspect, wherein the third step is performed by heat from the unmelted portion in the specific region. It is a process for extracting energy.

  The method for concentrating and separating a guest molecule of an inclusion compound according to a fourth aspect of the present invention includes a host molecule of the inclusion compound as a solvent and the guest molecule as a solute, and is disposed in a solution having a density different from that of the inclusion compound. A first step of generating the clathrate compound on the outer surface of the heat exchanger in a container in which the heat exchanger is accommodated and growing it into a lump, and part of the lump on the outer surface A second step of melting from the side and releasing the unmelted portion of the massive body from the outer surface, and repeating the first step and the second step at least once, whereby the inclusion compound and the solution A third step in which the unmelted portion is unevenly distributed in a specific region in the solution based on the density difference, and the concentration of the guest molecule in the specific region is relatively increased, and from a region different from the specific region, Remove the solution from the container. It is characterized by a fourth step of issuing.

  The method for concentrating and recovering the guest molecule of the clathrate compound according to the fifth aspect of the present invention is arranged in a solution containing a host molecule of the clathrate compound as a solvent and the guest molecule as a solute and having a density different from that of the clathrate compound. A first step of generating the clathrate compound on the outer surface of the heat exchanger in a container in which the heat exchanger is accommodated and growing it into a lump, and part of the lump on the outer surface A second step of melting from the side and releasing the unmelted portion of the massive body from the outer surface, and repeating the first step and the second step at least once, whereby the inclusion compound and the solution A third step in which the unmelted portion is unevenly distributed in a specific region in the solution based on the density difference, and the concentration of the guest molecule in the specific region is relatively increased; and the solution is removed from the specific region outside the container. 4th work to be taken out It is characterized by having and.

  The method for concentrating and recovering a guest molecule of an inclusion compound according to a sixth aspect of the present invention is the method for concentrating and recovering a guest molecule according to the fifth aspect, wherein the fourth step is performed from a region different from the specific region. After the solution is taken out of the container, the solution is a step of taking the solution out of the container from the specific region.

  The method for regenerating the guest molecule of the clathrate compound according to the seventh aspect of the present invention comprises a solution containing a host molecule of a used clathrate compound as a solvent and a guest molecule as a solute and having a density different from that of the clathrate compound. A first step of generating the clathrate compound on the outer surface of the heat exchanger in a container in which the heat exchanger disposed in the container is accommodated and growing it into a lump, and a part of the lump as the outside The inclusion compound and the solution are melted from the surface side and the second step of releasing the unmelted portion of the mass from the outer surface, and the first step and the second step are repeated at least once. And the third step of unevenly distributing the unmelted portion in a specific region in the solution based on the density difference between the solution and the relative concentration of the guest molecule in the specific region, and from the specific region to the outside of the container. Removing the solution A step, is characterized by having a fifth step of re-using the guest molecule contained in the solution taken out from the container.

  In the present invention, the purpose of concentrating guest molecules is not particularly limited. In particular, in the first to third embodiments, the purpose of concentrating the guest molecules is not limited, and as a result, the guest molecules need only be concentrated. However, strictly speaking, in the fourth embodiment, the purpose is to separate the guest molecules from the impurities, and in each of the fifth to sixth embodiments, the purpose is to collect the guest molecules. In this form, it can be said that it is intended to be reused for a certain purpose.

  The present invention includes a step of generating an inclusion compound on the outer surface of a heat exchanger disposed in a raw material solution and growing it into a lump, and a part of the lump from the outer surface side of the heat exchanger. The process of melting and detaching the unmelted part from the outer surface is repeated at least once so that the unmelted part is unevenly distributed in a specific region in the raw material solution based on the density difference between the clathrate compound and the raw material solution. The basic configuration is to relatively increase the concentration of guest molecules in the specific region. When the clathrate compound produced on the outer surface of the heat exchanger is melted from the outer surface side, the melted portion returns to the raw material solution, and can be used for the production of the next clathrate compound. In addition, since the unmelted portion floats or settles in the raw material solution based on the density difference between the clathrate compound and the raw material solution, the next time the clathrate compound is generated, the raw material is placed on the outer surface of the heat exchanger. A state in which there is no or almost no inclusion compound that hinders heat transfer to the solution can be realized, so that the effect of heat exchange by the heat exchanger can be kept high. Moreover, the unmelted part floats or settles in the raw material solution based on the density difference between the clathrate compound and the raw material solution, and a specific region in the raw material solution (when the undissolved part floats in the raw material solution) When the undissolved part settles in the raw material solution, it is concentrated in the lower region of the raw material solution and is unevenly distributed there. It can be relatively increased and thus the guest molecules can be concentrated.

  Further, when the generation and melting of the clathrate compound are repeated a plurality of times, the above-mentioned effects are repeated. That is, when the clathrate compound is melted, the melted portion returns to the raw material solution, which is used for the generation of the next clathrate compound, and less guest molecules are removed in vain. Further, the unmelted portion gathers in a specific region in the raw material solution based on the density difference between the clathrate compound and the raw material solution, and the concentration of the guest molecule can be relatively further increased. Further concentration is possible. The concentration of guest molecules in the raw material solution decreases, and the amount of clathrate compound that can be generated on the outer surface of the heat exchanger gradually decreases. Since there is almost no inclusion compound on the outer surface of the material and the heat transfer from the outer surface to the raw material solution remains high, the inclusion is possible even from a raw material solution with a low concentration of guest molecules. Compounds can be generated.

  Thus, according to the present invention, by repeatedly generating and melting the clathrate compound, guest molecules can be cumulatively concentrated from the raw material solution, and an efficient concentration technique for guest molecules can be realized. it can. In the present invention, it is more effective and preferable to repeat the generation and melting of the clathrate compound a plurality of times.

  When the unmelted part floats or settles in the raw material solution based on the density difference between the clathrate compound and the raw material solution, a part of the unmelted part is dispersed or suspended in the raw material solution. In some cases, a slurry of the clathrate compound is formed, but this slurry also floats or sinks and is unevenly distributed in a specific region in the raw material solution, thereby causing a relative increase in the concentration of guest molecules in the specific region, and thus guest molecules. Contributes to the concentration of

  The individual effects produced by the embodiments of the present invention are as follows.

  According to the first aspect of the present invention, it is possible to realize an efficient concentration method capable of concentrating guest molecules from a raw material solution without waste.

  According to the second aspect of the present invention, the concentration of guest molecules can be realized in the process of heat storage and heat dissipation in which heat energy is accumulated by the latent heat of the clathrate compound and heat energy is taken out by the heat exchanger. This means that a heat storage device that uses the clathrate compound as a heat storage material (for example, an internal fusion heat storage device) can be diverted to a guest molecule concentrating device.

  According to the 3rd form of this invention, a thermal energy can be taken out from an unmelted part simultaneously with making a guest molecule unevenly distribute and concentrate in the specific area | region in a raw material solution. Such an effect may cause problems in subsequent processing (for example, separation and recovery of guest molecules) if the unmelted portion is unevenly distributed as a lump in a specific region in the raw material solution. It is useful when it is preferable to keep the heat storage device, or when the heat storage device using the clathrate compound as the heat storage material is used instead of or as a guest molecule concentrating device.

  According to the fourth aspect of the present invention, after the guest molecules are unevenly distributed in a specific region in the raw material solution contained in the container and concentrated, the raw material solution in a region different from the specific region, that is, the guest Since the raw material solution having a relatively low molecular concentration is taken out of the container, it is possible to realize a method for concentrating and separating guest molecules capable of separating and leaving the guest molecules concentrated in the container. In addition, it is the same as in the case of the first embodiment that the guest molecules are more efficiently concentrated by repeating the generation and melting of the clathrate compound a plurality of times. Therefore, in order to efficiently leave the guest molecule in the container according to the fourth embodiment, it is preferable to repeat the generation and melting of the clathrate compound a plurality of times.

  According to the fifth aspect of the present invention, after the guest molecules are unevenly distributed in a specific region in the raw material solution accommodated in the container and concentrated, the concentration of the raw material solution in the specific region, that is, the guest molecule is Since a relatively high raw material solution is taken out of the container, it is possible to realize a method for concentrating and recovering guest molecules that allows the guest molecules concentrated in the container to be taken out of the container and recovered. In addition, it is the same as in the case of the first embodiment that the guest molecules are more efficiently concentrated by repeating the generation and melting of the clathrate compound a plurality of times. Therefore, in order to efficiently take out guest molecules from the container according to the fifth embodiment, it is preferable to repeat the generation and melting of the clathrate compound a plurality of times. In addition, according to the sixth embodiment, before the guest molecule concentrated in the container is taken out of the container, the guest molecule is concentrated to a region where the guest molecule becomes relatively low (separate from the specific region). The low concentration region raw material solution in the region may be taken out of the container.

  According to the seventh aspect of the present invention, using the method for concentrating and recovering guest molecules according to the fifth or sixth aspect, the host molecule and guest molecule of the clathrate compound used for a certain purpose are respectively used as solvents. The guest molecules can be recovered from the solution containing the solute and reused for that purpose, which is very economical in terms of resource reuse. In addition, when the said objective exists in utilization as a composition of a thermal storage material, there also exists an advantage that the thermal storage apparatus which uses an inclusion compound as a thermal storage material can be substituted or combined as a concentration apparatus of a guest molecule.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the present embodiment, a specific example of the clathrate compound will be described as a clathrate hydrate. However, just because the specific example is a clathrate hydrate, the clathrate other than the clathrate hydrate is used in the present invention. The present invention can be practiced with inclusion compounds other than inclusion hydrates, not excluding compounds. In addition, the clathrate hydrate has a higher density than the raw material solution, and an explanation will be given of a case where a lump (unmelted portion) of the unmelted clathrate compound settles in the raw material solution. The only difference is that the melting part exhibits the behavior of floating in the raw material solution, and the basic configuration is the same.

  FIG. 1 is a schematic explanatory diagram of an apparatus that generates clathrate hydrate, stores heat, melts this, and dissipates heat. In FIG. 1, a heat exchanger (heat transfer tube) 2 is disposed in a storage tank 1 in which a raw material solution L is stored.

  In the apparatus according to the present embodiment, the concentration of guest molecules can be realized in the process of heat storage and heat dissipation in which heat energy is accumulated by the latent heat of clathrate hydrate and the heat energy is taken out by the heat exchanger. That is, a heat storage device using clathrate hydrate as a heat storage material is diverted to a guest molecule concentrating device.

  The heat exchanger 2 meanders in the horizontal direction in the heat storage tank 1 and has a plurality of stages in the height direction, and a heat medium is circulated in the heat exchanger 2. The heat exchanger 2 may meander in the up-down direction without depending on the meandering in the horizontal direction. The raw material solution L may have a concentration of guest molecules that gives a harmonic melting point (harmonic melting point concentration), or a concentration lower than or higher than that.

  The apparatus shown in FIG. 1 is substantially the same as a so-called inner-melting type heat storage apparatus if compared to a heat storage apparatus. And in this device, by executing a heat storage step for storing thermal energy and a heat release step for releasing or taking out the stored thermal energy, in other words, a heat storage operation for realizing the heat storage step By performing a heat dissipation operation for realizing the heat dissipation process, the clathrate hydrate abundance ratio or the concentration of the guest molecule is separated into a relatively high region and a low region.

  In the apparatus according to this embodiment, a heat storage process and a heat dissipation process are performed.

<Heat storage process (heat storage operation)>
A heat medium having a temperature lower than the clathrate hydrate formation temperature is circulated through the heat exchanger (heat transfer tube) 2, and the raw material solution L is heat-exchanged and cooled on the outer surface of the heat exchanger 2 to be clathrate hydrate L1. Is generated. As shown in FIG. 1, the clathrate hydrate L1 adheres to and accumulates on the outer surface of the heat exchanger 2, and a mass of the clathrate hydrate L1 is formed around the heat exchanger 2. The

<Heat dissipation process (heat dissipation operation)>
A heat medium having a temperature higher than the melting temperature of the clathrate hydrate is circulated through the heat exchanger 2 to exchange heat with the clathrate hydrate L1 on the outer surface of the heat exchanger 2, and the heat medium is cooled to cool energy. Is taken out. The clathrate hydrate L1 melts from the portion in contact with the outer surface of the heat exchanger 2, and the raw material solution L formed by the melting is higher than the melting point of the clathrate hydrate L1, so And is unevenly distributed above the storage tank 1. On the other hand, the mass of the clathrate hydrate L1 that remains unmelted (unmelted portion) is detached from the surface of the heat exchanger 2, and according to the density difference between the clathrate hydrate L1 and the raw material solution L, Therefore, it sinks downward by gravity.

  Since this unmelted part is a part of the clathrate hydrate lump, unlike the clathrate hydrate slurry, the dispersibility in the solvent is relatively small, and the cohesiveness in the solvent is also compared. Small. Therefore, it settles down more rapidly than the slurry according to the density difference between the clathrate hydrate and the raw material solution. In the process, a part of the unmelted part is dispersed or suspended in the raw material solution to become a slurry, and settles at a relatively slow rate. Thus, the unmelted portion is unevenly distributed in the region below the storage tank 1 in the form of a lump or slurry. Further, when the unmelted portion that has been unevenly distributed in the lower region of the storage tank 1 is melted, as long as a long time sufficient to diffusely mix with the upper raw material solution L has not passed, or the upper region and the lower region Unless the forcible stirring is performed between the two, the raw material solution having a concentration higher than the concentration of the guest molecules in the original raw material solution L is retained. Thus, as shown in FIG. 2, a high concentration region A is formed below the storage tank 1, and a low concentration region B is formed above.

<Repetition of heat storage process and heat dissipation process>
A step of generating clathrate hydrate L1 on the outer surface of the heat exchanger 2 disposed in the raw material solution L and growing it into a lump (heat storage step), and a part of the lump is transferred to the heat exchanger 2 When the process of melting from the outer surface side and detaching the unmelted part from the outer surface (heat dissipation process) is repeated at least once, the density difference between the clathrate hydrate L1 and the raw material solution L is not increased. The melting part is unevenly distributed in a specific region in the raw material solution, the abundance ratio of clathrate hydrate in the specific region is relatively increased, and the concentration of guest molecules that appear when the unmelted part is melted is relatively high. To increase. As a result, the concentration of guest molecules in the specific region is relatively increased.

  Here, since the unmelted part is a part of the clathrate hydrate lump, unlike the clathrate hydrate slurry, the dispersibility in the solvent is relatively small, and the cohesiveness in the solvent Is also relatively small. Therefore, it settles downward according to the density difference between the clathrate hydrate and the raw material solution more rapidly than the slurry. In the process, a part of the unmelted portion is dispersed or suspended in the raw material solution to become a slurry, and settles at a relatively low speed. Thus, the unmelted portion is unevenly distributed in the region below the storage tank 1 in the form of a lump or slurry. Further, when the unmelted portion that has been unevenly distributed in the lower region of the storage tank 1 is melted, for example, unless a long time sufficient for diffusing and mixing with the upper raw material solution L has passed, or the upper region and the lower region Unless the forcible stirring is performed, the raw material solution has a concentration higher than the concentration of the guest molecules in the original raw material solution L and stays there. Further, the unmelted portion, slurry and raw material solution that have stayed in the lower region are subjected to forcible agitation between the upper region and the lower region, for example, in the process of repeated heat storage and heat release. As long as there is not, it will be in the state confined to the said lower area | region. Thus, a low concentration region is formed above the storage tank 1, and a high concentration region is formed below.

  Therefore, according to the present invention, the concentration of guest molecules in a specific region in the raw material solution is relatively increased by repeating the generation and melting of clathrate hydrate at least once in the raw material solution. Can be promoted.

  In addition, when the clathrate hydrate is repeatedly generated and melted, the clathrate hydrate adhering to the outer surface of the heat exchanger is melted each time the clathrate hydrate is repeated, and the unmelted portion is outside the heat exchanger. Get away from the surface. Then, due to the density difference between the clathrate hydrate and the raw material solution, the unmelted part is a specific region in the raw material solution (if the clathrate hydrate has a higher density than the raw material solution, The concentration of clathrate hydrate or the concentration of guest molecules gradually increases, and a high concentration region is formed in the specific region, and at the same time, the inclusion in the raw material solution in a region other than the specific region The abundance ratio of hydrate or the concentration of guest molecules decreases gradually. As a result, the periphery of the outer surface of the heat exchanger becomes a low-concentration region, and an environment in which clathrate hydrates are difficult to be generated.

  However, when the clathrate hydrate adhering to the outer surface of the heat exchanger is melted and the unmelted part is detached from the outer surface of the heat exchanger, the outer surface of the heat exchanger becomes the raw material solution. Since there is no or almost no clathrate hydrate that hinders heat transfer to the heat exchanger, the heat exchange effect by the heat exchanger remains high, and therefore continues even in the low concentration region environment. Formation of clathrate hydrate occurs. Of course, when the inclusion ratio of the clathrate hydrate or the concentration of the guest molecule decreases gradually, the amount of clathrate hydrate generated on the outer surface of the heat exchanger also decreases, but the heat transferability of the outer surface of the heat exchanger More clathrate hydrates are produced by the amount that does not decrease, resulting in lumps.

  Thus, by repeating the generation and melting of clathrate hydrate, the surroundings of the outer surface of the heat exchanger will be in a low concentration region, and even in an environment where clathrate hydrate is difficult to be generated, it is possible to identify in the raw material solution. A high concentration region is formed in the region, and at the same time, a low concentration region is formed in a region other than the specific region, and this is repeated.

  Therefore, according to the present invention, even if the generation and melting of clathrate hydrate are repeated several times in the raw material solution, the clathrate hydrate or its guest molecule is cumulatively accumulated in the lower region from the raw material solution. Can be unevenly distributed, and the inclusion hydrate content ratio or the concentration of the guest molecule can be quickly and efficiently changed into a region where the concentration of the guest molecule is relatively high and a region where the concentration of the guest molecule is relatively low. The separation can be performed so that the difference becomes clearer, and the concentration of the guest molecules in a specific region in the raw material solution can be relatively increased and the concentration can be facilitated.

  As mentioned above, when the clathrate hydrate adhering to the outer surface of the heat exchanger is melted and the unmelted part is detached from the outer surface of the heat exchanger, heat exchange by the heat exchanger is performed. This effect remains high, so that clathrate hydrate continues to be produced even in a low-concentration environment. This means that according to the present invention, the guest molecules can be quickly and efficiently separated from the raw material solution having a low concentration of guest molecules. Such an effect of the present invention is particularly beneficial when a guest molecule of an inclusion compound is recovered or concentrated from a used raw material solution and intended to be reused as a heat storage material composition.

  In addition, compared to the amount of clathrate hydrate that melts on the outer surface of the heat exchanger 2, the amount of clathrate hydrate in the unmelted part that separates from the outer surface and settles downward as a result of the melting. Usually there are more. In particular, when the heat exchanger is a heat transfer tube, the clathrate hydrate lump is affected by gravity and a limited portion of the clathrate hydrate lump above the heat transfer tube (transfer Only the portion immediately above or in the vicinity of the heat tube is likely to melt, and thus more unmelted portions are likely to settle downward. In such a case, particularly when the heat exchanger is a heat transfer tube, the difference in the clathrate hydrate abundance or the concentration of the guest molecule is more easily clarified, and the low concentration region and the high concentration region Since the formation is likely to occur efficiently and quickly, it is preferable as an embodiment of the present invention regardless of whether the heat storage step and the heat release step are repeated.

  FIG. 3 shows that the clathrate hydrate of FIG. 1 is produced using a 30 wt% aqueous solution that is less than the harmonic melting point concentration of tetra-n-butylammonium bromide (TBAB) as the guest molecule of the clathrate hydrate. The distribution of TBAB concentration in the raw material solution in the storage tank 1 after the generation and melting of clathrate hydrate was repeated a plurality of times by a device that stores heat and melts and dissipates it. It is. Here, the horizontal axis indicates the TBAB concentration in the raw material solution, and the vertical axis indicates the height ratio where the liquid surface height of the raw material solution in the storage tank 1 is 1. According to FIG. 3, the density of the TBAB clathrate hydrate is larger than that of the raw material solution, but it is separated as a region having a relatively high TBAB concentration at the bottom and a region having a relatively low TBAB concentration at the top. .

  In the present embodiment, further improvements can be made from various viewpoints, for example, as follows.

(I) Improvement of efficiency of heat dissipation process In FIG. 2, the area | region where the existence ratio of clathrate hydrate is high is formed in the lower part of the storage tank 1. In FIG. FIG. 2 shows an example of one heat exchanger meandering in the horizontal direction and continuously forming a plurality of stages in the height direction. The heat exchanger is provided separately in the low region (low concentration region) and the lower region, that is, the region where the clathrate hydrate is high, and in the heat dissipation process, the clathrate hydrate is mainly present in the high proportion If heat energy is taken out by a heat exchanger provided in the region (high concentration region), the heat exchanger for taking out heat energy efficiently and in a region where the clathrate hydrate content is high If it is provided, the heat energy can be taken out more efficiently.

(Ii) Extraction of the raw material solution from the region where the concentration of guest molecules is low As shown in FIG. 4, the guest molecules are concentrated and concentrated in a specific region in the raw material solution stored in the storage tank 1. After forming the region A having a relatively high inclusion hydrate ratio or guest molecule concentration (high concentration region) A, a region having a relatively low inclusion hydrate concentration or guest molecule concentration (low) The raw material solution in the low concentration region B is taken out of the storage tank 1 from the concentration region (B) by the pump 3. Thereby, the concentration separation method of the guest molecule which can isolate | separate and leave the guest molecule concentrated in the storage tank 1 is realizable. In addition, it is the same as that of the case of FIG. 2 that a guest molecule is more efficiently concentrated by repeating the production | generation and melting | fusing of clathrate hydrate several times. Therefore, in order to efficiently concentrate the guest molecule in the form shown in FIG. 4 and leave it in the container, it is preferable to repeat the generation and melting of the clathrate hydrate a plurality of times.

  In addition, when taking out the raw material solution from the low concentration region B to the outside of the storage tank 1 with a pump or the like, the clathrate hydrate or slurry existing in the high concentration region A or the raw material solution existing in the low concentration region B In order to prevent mixing by convection and to perform efficient concentration and separation, a plurality of raw material solution suction ports are provided at a low flow rate, or the raw material solution suction ports are placed on the liquid surface in the low concentration region B. For example, a floating mechanism may be considered.

(Iii) Extraction of raw material solution from a region having a high concentration of guest molecules As shown in FIG. 5, the guest molecules are unevenly distributed in a specific region in the raw material solution stored in the storage tank 1, concentrated, and wrapped. After forming a region (high concentration region) A in which the abundance ratio of the wet hydrate or the concentration of guest molecules is relatively high, the raw material solution of the high concentration region A is extracted from the high concentration region A by the pump 4 outside the storage tank 1. Take out. Thereby, the concentration collection method of the guest molecule which can take out and collect the guest molecule concentrated in the storage tank 1 out of the storage tank 1 is realizable. In addition, it is the same as that of the case of FIG. 2 that a guest molecule is more efficiently concentrated by repeating the production | generation and melting | fusing of clathrate hydrate several times. Therefore, in order to efficiently take out guest molecules from the container in the form shown in FIG. 5, it is preferable to repeat the generation and melting of clathrate hydrate a plurality of times.

  In addition, when taking out the raw material solution from the high concentration region A to the outside of the storage tank 1 with a pump or the like, the clathrate hydrate or slurry existing in the high concentration region A or the raw material solution existing in the low concentration region B In order to prevent mixing by convection and to perform efficient concentration and separation, it is conceivable to provide a plurality of raw material solution inlets at a low flow rate. Also, the opening direction of the raw material solution suction port should be the direction in which more clathrate hydrate and slurry are present (the bottom direction of the heat storage tank), the diameter of the raw material solution suction port is the mass of the clathrate hydrate mass By enlarging the unmelted portion so as to be easily sucked, a raw material solution having a high concentration of guest molecules can be taken out, and efficient concentrated separation is possible.

(Iv) Removal of the raw material solution from the high concentration region of the guest molecule after the extraction of the raw material solution from the low concentration region of the guest molecule As shown in FIG. 6, the raw material solution accommodated in the storage tank 1 After the guest molecules are unevenly distributed and concentrated in a specific region in the region, a region (high concentration region) A having a relatively high clathrate hydrate abundance ratio (guest molecule concentration) is formed. Opening (the on-off valve 7 is closed), the raw material solution of this low concentration region B from the region B (low concentration region) B in which the inclusion hydrate abundance ratio (guest molecule concentration) is relatively low is stored by the pump 5 After being taken out from 1, the on-off valve 7 is opened (the on-off valve 6 is closed), and the raw material solution in the high concentration region A is taken out from the high concentration region A to the outside of the storage tank 1 by the pump 5. As a result, after the guest molecules concentrated in the storage tank 1 are separated and left, the guest molecules concentrated and left in the storage tank 1 can be taken out of the storage tank 1 and recovered. It is possible to realize a method for concentrating and recovering guest molecules having a high density.

  A pump may be provided separately for taking out the raw material solution in the low concentration region B and for taking out the raw material solution in the high concentration region A.

(V) Regeneration method FIG. 7 shows a method for concentrating and recovering guest molecules from a raw material solution using the method of concentrating and recovering guest molecules of clathrate hydrate shown in FIGS. Shows a playback device so that it can.

  In FIG. 7, a raw material solution (concentrated solution) having a high guest molecule concentration is extracted from a storage tank (concentrator) 1, stored in a concentrated solution storage tank 9, and the concentrated solution is heated using a heater 11 in an evaporator 10. Thus, the water is reduced to obtain a highly concentrated solution, which is stored in the highly concentrated solution storage tank 12. Next, guest molecules are precipitated from the highly concentrated solution by a crystallizer (separator) 13 and separated from the liquid to obtain solid guest molecules.

  By doing so, it is possible to regenerate a guest molecule having a high purity without impurities from the concentrated solution, and it can be obtained in a solid state, which facilitates storage and transportation.

It is a schematic diagram of one embodiment device of the present invention, and shows a heat storage state. The heat dissipation state of the apparatus shown in FIG. 1 is shown. It is a figure which shows the mode of the phase separation of a raw material solution regarding a height direction. It is a figure which shows the modification of the apparatus shown in FIG. It is a figure which shows the other modification of the apparatus shown in FIG. It is a figure which shows the further another modification of the apparatus shown in FIG. It is a figure which shows the apparatus which performs concentration collection | recovery of the guest molecule of clathrate hydrate using each apparatus shown in FIGS.

Explanation of symbols

1 Storage tank 2 Heat exchanger L Raw material solution L1 Inclusion compound (inclusion hydrate)

Claims (7)

The inclusion compound is generated on the outer surface of a heat exchanger that contains a host molecule of the inclusion compound as a solvent and the guest molecule as a solute and is disposed in a solution having a density different from that of the inclusion compound, and grows into a lump. A first step of
A second step of detaching the unmelted portion of the mass from the outer surface by melting a part of the mass from the outer surface side;
By repeating the first step and the second step at least once, the unmelted portion is unevenly distributed in a specific region in the solution based on the density difference between the inclusion compound and the solution, and the specific region And a third step of relatively increasing the concentration of the guest molecule in the method of concentrating guest molecules of an inclusion compound.   The first step is a step of accumulating thermal energy due to the latent heat of the clathrate compound, and the second step is a step of extracting thermal energy from a part of the lump by the heat exchanger. A method for concentrating guest molecules of the clathrate compound according to claim 1.   The said 3rd process is a process of taking out heat energy from the said unmelted part in the said specific area | region, The concentration method of the guest molecule of the clathrate compound of Claim 2 characterized by the above-mentioned. The outer surface of the heat exchanger is contained in a container containing a heat exchanger disposed in a solution having a host molecule of the inclusion compound as a solvent and a guest molecule as a solute and having a density different from that of the inclusion compound. A first step of generating the inclusion compound and growing it into a mass;
A second step of melting a part of the mass from the side of the outer surface and releasing an unmelted portion of the mass from the outer surface;
By repeating the first step and the second step at least once, the unmelted portion is unevenly distributed in a specific region in the solution based on the density difference between the inclusion compound and the solution, and the specific region A third step of relatively increasing the concentration of the guest molecule in
And a fourth step of extracting the solution from the region different from the specific region to the outside of the container. The outer surface of the heat exchanger is contained in a container containing a heat exchanger disposed in a solution having a host molecule of the inclusion compound as a solvent and a guest molecule as a solute and having a density different from that of the inclusion compound. A first step of generating the inclusion compound and growing it into a mass;
A second step of melting a part of the mass from the side of the outer surface and releasing an unmelted portion of the mass from the outer surface;
By repeating the first step and the second step at least once, the unmelted portion is unevenly distributed in a specific region in the solution based on the density difference between the inclusion compound and the solution, and the specific region A third step of relatively increasing the concentration of the guest molecule in
And a fourth step of extracting the solution from the specific region to the outside of the container. A method for concentrating and recovering guest molecules of an inclusion compound.   The said 4th process is a process of taking out the said solution out of the said container from the said specific area | region after taking out the said solution out of the said container from the area | region different from the said specific area | region. A method for concentrating and recovering guest molecules of an inclusion compound. The heat exchanger is disposed in a container containing a heat exchanger disposed in a solution containing a host molecule of a used clathrate compound as a solvent and a guest molecule as a solute and having a density different from that of the clathrate compound. Generating the inclusion compound on the outer surface and growing it into a lump,
A second step of melting a part of the mass from the side of the outer surface and releasing an unmelted portion of the mass from the outer surface;
By repeating the first step and the second step at least once, the unmelted portion is unevenly distributed in a specific region in the solution based on the density difference between the inclusion compound and the solution, and the specific region A third step of relatively increasing the concentration of the guest molecule in
A fourth step of taking the solution out of the container from the specific area;
And a fifth step of reusing the guest molecules contained in the solution taken out of the container. A method for regenerating a guest molecule of an inclusion compound.

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