JP4915399B2 - Method and apparatus for collecting and releasing gas using a hydrate containing a quaternary ammonium salt as a guest molecule - Google Patents

Description

  The present invention relates to a technique for collecting and releasing a gas using a hydrate containing a quaternary ammonium salt as a guest molecule, and more specifically, bringing an aqueous solution containing a quaternary ammonium salt as a solute into contact with the gas, By cooling at a temperature higher than 0 ° C., a hydrate that collects gas is generated, and further, the hydrate is dispersed or suspended in an aqueous solution or water to generate a hydrate slurry. Heating the hydrate slurry produced in step 1 and the first step to melt the hydrate therein, thereby removing gas from the hydrate produced in the first step. And a second step of generating an aqueous solution containing a quaternary ammonium salt as a solute and an apparatus for realizing the method.

In the present invention, the meanings or interpretations of the following terms are as follows. The meaning or interpretation of this term does not preclude the technical scope of the present invention from reaching an equivalent scope.
(1) “Hydrate” is an abbreviation for clathrate hydrate. In the structure (inclusion lattice) such as a tunnel shape, a layer shape, a network shape, and a cage shape formed by a molecule or a compound called a host or a host material (ie, host molecule) (ie, a host molecule), another molecule or compound called a guest material (ie, a host material) A substance formed and formed by entering or taking in a guest molecule) is called an inclusion compound. Examples of guest molecules include quaternary ammonium salts typified by alkyl ammonium salts such as tetra-n-butylammonium salt, tetra-isopentylammonium salt, tri-n-butyl-pentylammonium salt, alkylphosphonium salts, alkylsulfonium salts, and the like. is there. Examples of host molecules are water and cyclodextrins. An inclusion compound in which the host molecule is water is an inclusion hydrate. The “hydrate” in the present invention includes quasi-clathrate hydrate.
(2) An aqueous solution of a clathrate hydrate guest molecule, more specifically, an aqueous solution containing one or two or more guest molecules as a solute and water as a solvent may be abbreviated as an “guest molecule aqueous solution”.
(3) “Slurry of hydrate” refers to a slurry in which a hydrate is dispersed or suspended in an aqueous solution or aqueous solvent of guest molecules. Even if the amount of hydrate is small (in other words, even if the proportion of hydrate is low), if it is dispersed or suspended in the aqueous solution or aqueous solvent, it corresponds to “a slurry of hydrate”. To do. The “hydrate slurry” may be simply referred to as “slurry” in context or for convenience.
(4) “Hydrate formation temperature” refers to the temperature at which a hydrate is formed in an aqueous solution of the hydrate guest molecule when cooled.

A technique of using a hydrate containing a quaternary ammonium salt as a guest molecule as a gas separating agent and utilizing it for gas separation or concentration has been studied (Patent Documents 1 to 3, Non-Patent Documents 1 and 2). .
Japanese Patent No. 3826176 JP 2006-117485 A JP 2006-206635 A Antoin Chapoy, Ross Anderson, and Bahman Tohidi, “Low-PressureMolecular Hydrogen Storage in Semi-clathrate Hydrates of Quaternary AmmoniumCompounds” Journal of American Chemical Society 2007, 129, pp. 746-747. Nguyen Hong Duc, Fabien Chauvy, Jean-Michel Herri, “CO2capture by hydrate crystallization-A potential solution for gas emission ofsteelmaking industry,” Available online 30 November 2006, Internet <URL: http://www.emse.fr/spin/ depscientifiques / GENERIC / hydrates / publications / abstract2006a.htm><URL:http://www.aseanenvironment.info/Abstract/43005208.pdf>

However, none of the prior arts are in the research stage and are not in a stage that can withstand realistic applications. In order to use a hydrate containing a quaternary ammonium salt as a guest molecule as a gas separating agent, one of the necessary conditions to be able to withstand practical applications is to use a quaternary ammonium salt as a guest. A cycle of collecting a gas using a hydrate contained as a molecule and releasing the gas collected from the hydrate to separate a desired gas and collect the guest molecule is more efficient or It is to be realized economically. Although the techniques described in Patent Documents 3 and 4 seem to be one of the candidates that can satisfy this necessary condition, the energy efficiency as a whole is not sufficient and there is room for improvement.
Conventionally, many substance names belonging to quaternary ammonium salts have been cited as hydrate guest molecules that can be used for gas separation and concentration. However, the quaternary ammonium salts actually used for research are tetra-n-butylammonium halides (particularly tetra-n-butylammonium bromide (TBAB), tetra-n-butylammonium hydroxide (TBAOH), tetra-n-fluoride). It can be said that it is generally limited to butylammonium (TBAF).

  The present invention has been made in view of the above points, and is a technique for collecting and releasing a gas using a hydrate containing a quaternary ammonium salt as a guest molecule in order to separate the gas, An object of the present invention is to provide a gas that can efficiently or economically collect and release a gas and recover a guest molecule.

  In order to achieve the above object, a method of collecting and releasing a gas according to the first embodiment of the present invention collects and releases a gas using a hydrate containing a quaternary ammonium salt as a guest molecule. In this method, an aqueous solution of the guest molecule is brought into contact with a gas and cooled at a temperature higher than 0 ° C. to generate a hydrate that collects the gas, and the hydrate is further added to the aqueous solution or water. The first step for producing a slurry formed by dispersion or suspension, and the slurry produced in the first step is heated to melt the hydrate therein, thereby collecting the hydrate. And a second step of generating an aqueous solution of the guest molecule, and a part or all of the slurry generated in the first step and the guest molecule generated in the second step Part of an aqueous solution of The aqueous solution of the guest molecules cooled by the heat exchange is used as part or all of the aqueous solution of the guest molecules in the first step, and the slurry heated by the heat exchange is used as the first It is characterized in that it is used as a part or all of the slurry in step 2.

  The method for collecting and releasing the gas according to the second aspect of the present invention is the method according to the first aspect, wherein the gas to be brought into contact with the aqueous solution of the guest molecule in the first step is contacted before the contact. It has the gas cooling process to cool, It is characterized by the above-mentioned.

  A method for collecting and releasing a gas according to the third aspect of the present invention is a method according to any one of the first and second aspects, wherein the first step includes an aqueous solution of the guest molecule, a gas, And a step of cooling at a temperature of 7 ° C. or lower while the second step has a step of heating the slurry produced in the first step at a temperature of 15 ° C. or higher. To do.

  The method for collecting and releasing the gas according to the fourth aspect of the present invention is the method according to the first aspect, wherein the first step mixes or stirs the aqueous solution of the guest molecule and the gas. It has the process of cooling at the temperature of 15 degreeC or more, It is characterized by the above-mentioned.

A method for collecting and releasing a gas according to the fifth aspect of the present invention is the method according to any one of the first to fourth aspects, wherein the aqueous solution of the guest molecule is a tetraisopentylammonium salt or a tetra It contains two or more kinds of quaternary ammonium salts containing an isopentylammonium salt as a solute.
If the aqueous solution of the guest molecule is an aqueous solution containing two or more kinds of quaternary ammonium salts containing tetraisopentylammonium salt or tetraisopentylammonium salt as a solute, the hydrate formation temperature is higher than 0 ° C or It is easy to adjust the temperature to 15 ° C. or higher, and therefore, a method for collecting and releasing the gas according to the present invention can be easily configured.
A typical example of a tetraisopentylammonium salt is tetraisopentylammonium bromide. The harmonic melting point of tetraisopentylammonium bromide hydrate is 30 ° C., and when cooling the aqueous solution (ie, when forming a hydrate), cooling at a temperature higher than 0 ° C. or 15 ° C. or higher. By doing so, a hydrate can be generated, so that no particular cooling device is required, energy can be saved, and it is efficient or economical.

In the present invention, the aqueous solution of the guest molecule is preferably an aqueous solution containing two or more kinds of quaternary ammonium salts containing a tetraisopentylammonium salt as a solute, but a quaternary other than the tetraisopentylammonium salt. One of the ammonium salts is preferably a tetra-n-butylammonium salt. Since tetra-n-butylammonium salt is relatively inexpensive and easily available, a method for collecting and releasing economically excellent gas can be constructed. (The same applies to the ninth, fourteenth and nineteenth embodiments.)
A typical example of a tetra n butyl ammonium salt is tetra n butyl ammonium bromide. If an aqueous solution containing tetraisopentylammonium bromide and tetra-n-butylammonium bromide as solutes, the hydrate formation temperature can be easily adjusted to a temperature higher than 0 ° C. or a temperature of 15 ° C. or higher. A method of collecting and releasing can be easily configured.

The method for collecting and releasing a gas according to the sixth aspect of the present invention is a method according to any one of the first to fifth aspects, in order to cool the aqueous solution of the guest molecule in the first step. A part or all of the heat energy used for the heat is heat energy extracted from a region in which cold is held in advance.
In addition, the “region having cold heat in advance” refers to a part of or all of the heat energy required to bring the temperature of the aqueous solution of guest molecules below the hydrate formation temperature. It refers to a place, area, or space that can be physically determined, and is typically a heat storage tank (or cold storage tank), a heat storage device (or cold storage device), a container that stores a heat storage material (or cold storage material), or the like. More specifically, wells, geological formations or water storage tanks that store groundwater, liquefied natural gas storage facilities or transport facilities (including transport piping), air (or outside air), or external or surrounding environments are included. (Refer to the seventh, eighth and sixteenth embodiments).

  The method for collecting and releasing a gas according to the seventh aspect of the present invention is a method according to any one of the first to sixth aspects, in order to heat the hydrate slurry in the second step. Part or all of the thermal energy used in the above is heat energy transmitted from the atmosphere or other external or surrounding environment.

  A method for collecting and releasing a gas according to an eighth aspect of the present invention is a method for collecting and releasing a gas using a hydrate containing a quaternary ammonium salt as a guest molecule, wherein the guest molecule The aqueous solution is brought into contact with a gas and cooled at a temperature of 15 ° C. or higher to produce a hydrate that collects the gas, and a slurry in which the hydrate is dispersed or suspended in the aqueous solution or water. The first step to be generated and the slurry generated in the first step are heated to melt the hydrate therein, thereby releasing the gas collected by the hydrate, and And a second step of generating an aqueous solution of guest molecules.

  The method for collecting and releasing a gas according to the ninth aspect of the present invention is the method according to the eighth aspect, wherein the aqueous solution of the guest molecule contains a tetraisopentylammonium salt or a tetraisopentylammonium salt. It contains two or more kinds of quaternary ammonium salts as a solute.

  An apparatus for collecting and releasing a gas according to the tenth aspect of the present invention is an apparatus for collecting and releasing a gas using a hydrate containing a quaternary ammonium salt as a guest molecule, the guest molecule The aqueous solution is brought into contact with a gas and cooled at a temperature higher than 0 ° C., thereby generating a hydrate in which the gas is collected, and a slurry in which the hydrate is dispersed or suspended in the aqueous solution or water. Gas to be generated and gas that heats the slurry generated in the gas collector and melts hydrates in the slurry, thereby releasing gas and generating an aqueous solution of the guest molecule A heat exchanging device for exchanging heat between a part or all of the aqueous solution of the guest molecules generated in the gas releasing device and a part or all of the slurry generated in the gas collecting device; By heat exchange device A first supply device that supplies the rejected aqueous solution of the guest molecules to the gas collection device, and a second supply device that supplies the slurry heated by the heat exchange device to the gas release device. It is characterized by.

  An apparatus for collecting and releasing a gas according to an eleventh aspect of the present invention is the apparatus according to the tenth aspect, wherein the gas brought into contact with the aqueous solution of the guest molecule in the gas collection device is in contact therewith. A cooling device for cooling in advance is provided.

  An apparatus for collecting and releasing a gas according to a twelfth aspect of the present invention is the apparatus according to any of the tenth and eleventh aspects, wherein the aqueous solution of the guest molecule and the gas are contained in the gas collection apparatus. Are mixed or stirred and cooled at a temperature of 7 ° C. or lower, and the hydrate slurry is heated at a temperature of 15 ° C. or higher in the gas release device.

  An apparatus for collecting and releasing a gas according to a thirteenth aspect of the present invention is the apparatus according to any one of the tenth to twelfth aspects, wherein the aqueous solution of the guest molecule and the gas are contained in the gas collector. Are mixed or stirred and cooled at a temperature of 15 ° C. or higher.

  An apparatus for collecting and releasing a gas according to a fourteenth aspect of the present invention is the apparatus according to any one of the tenth to thirteenth aspects, wherein the aqueous solution of the guest molecule is a tetraisopentylammonium salt or a tetra It contains two or more kinds of quaternary ammonium salts containing an isopentylammonium salt as a solute.

  An apparatus for collecting and releasing a gas according to the fifteenth aspect of the present invention is the apparatus according to any one of the tenth to fourteenth aspects, wherein the aqueous solution of the guest molecule is cooled in the gas collection apparatus. A part or all of the heat energy used for the heat energy is heat energy extracted from a region in which cold is held in advance.

  An apparatus for collecting and releasing a gas according to a sixteenth aspect of the present invention is the apparatus according to the fifteenth aspect, wherein the region in which the cold is previously held is a liquefied natural gas storage facility, well or groundwater It is a stratum that stores

  An apparatus for collecting and releasing a gas according to a seventeenth aspect of the present invention is the apparatus according to any one of the tenth to sixteenth aspects, and heats a hydrate slurry in the gas discharge apparatus. A part or all of the heat energy used for this purpose is heat energy transmitted from the atmosphere or other external or surrounding environment.

  An apparatus for collecting and releasing a gas according to an eighteenth aspect of the present invention is an apparatus for collecting and releasing a gas using a hydrate containing a quaternary ammonium salt as a guest molecule, wherein the guest molecule A slurry obtained by bringing the aqueous solution into contact with a gas and cooling at a temperature of 15 ° C. or more, thereby generating a hydrate that collects the gas, and further dispersing or suspending the hydrate in the aqueous solution or water. Gas to be generated and gas that heats the slurry generated in the gas collector and melts hydrates in the slurry, thereby releasing gas and generating an aqueous solution of the guest molecule And a discharge device.

  An apparatus for collecting and releasing a gas according to a nineteenth aspect of the present invention is the apparatus according to the eighteenth aspect, wherein the aqueous solution of the guest molecule contains a tetraisopentylammonium salt or a tetraisopentylammonium salt. It contains two or more kinds of quaternary ammonium salts as a solute.

  In each form of the present invention, when gas is collected using a hydrate containing a quaternary ammonium salt as a guest molecule, it is desirable to apply pressure in order to facilitate the collection. In this case, the pressure is less than 2 MPa (usually 1 MPa or less, preferably about 0.1 to 0.7 MPa), and no special high pressure is required (see Patent Documents 1 to 3).

According to the present invention, gas is collected using a hydrate containing a quaternary ammonium salt as a guest molecule, the gas is separated by releasing the collected gas, and the guest molecule is recovered. A technique can be provided in which the cycle can be realized more efficiently or economically and thus can withstand realistic applications.
According to the present invention, gas is collected using a hydrate containing a quaternary ammonium salt as a guest molecule, and the gas is separated by releasing the collected gas. It is possible to provide a technique capable of realizing a cycle in which the heat exchange between the slurry and the aqueous solution of the guest molecule is performed to reduce energy consumption, and thus can withstand realistic applications.

Furthermore, in this invention, when the hydrate formation temperature of the hydrate which uses a quaternary ammonium salt as a guest molecule belongs to the range of 0-30 degreeC, the temperature of the extent (at most about 0-30 degreeC) By adjusting, gas collection and release can be controlled, so that energy consumption is low and economical gas separation can be realized. For example, when the outside air temperature is higher than the hydrate formation temperature, the aqueous solution of the guest molecule is cooled to collect gas in the hydrate, and at least a part of the hydrate is removed using the thermal energy of the outside air. It is possible to melt and thereby release the gas. In addition, when the outside air temperature is lower than the hydrate formation temperature, the aqueous solution of the guest molecule is cooled using the thermal energy of the outside air, thereby collecting the gas in at least a part of the hydrate, and by heating. The hydrate can be melted and the gas released. In any case, since the thermal energy of the outside air is used, energy consumption is relatively reduced, and economical gas separation becomes possible.
The effect which each form of this invention has is as follows.

  According to the first aspect of the present invention, a part or all of the clathrate hydrate slurry after collecting the gas and before releasing the gas (in other words, the first step And a part or all of the aqueous solution of the guest molecule after releasing the gas and before collecting the gas (the slurry produced in step 2 before being heated in the second step) In other words, since the aqueous solution generated in the second step and before cooling in the first step) is heat-exchanged, the energy required for cooling in the first step and the second step The energy required for heating can be reduced. Moreover, since what is heat-exchanged with the aqueous solution of guest molecules is a slurry of a hydrate rich in fluidity, heat exchange as described above is relatively easy and can be performed continuously. Therefore, energy can be continuously saved when gas is collected and released through heat exchange.

  When the aqueous solution of the guest molecule is cooled, if the aqueous solution comes into contact with a warm gas, the temperature of the aqueous solution rises, and the hydrate formation efficiency, and hence the gas collection efficiency, is reduced. On the other hand, according to the second embodiment of the present invention, since it has a gas cooling step for cooling the gas to be collected in advance, when the aqueous solution of guest molecules is cooled, the aqueous solution comes into contact with the cooled gas. In this case, the temperature rise of the aqueous solution is suppressed or the temperature is lowered, so that the clathrate hydrate formation efficiency, and hence the gas collection efficiency is increased.

  When the aqueous solution of guest molecules is cooled, a phenomenon in which clathrate hydrates are not immediately formed even when cooled below the hydrate formation temperature, that is, a supercooling phenomenon may occur. When supercooling occurs, gas trapping does not occur as planned, and if supercooling is released at an unexpected location, it is included in the inner wall of the pipe, heat transfer surface of the heat exchanger, etc. This causes problems such as adhesion of hydrates, increased pressure loss, and malfunction of equipment / equipment. On the other hand, according to the third aspect of the present invention, since the aqueous solution of the guest molecule and the gas are mixed or stirred in the first step, the supercooling is quickly released, and the generated clathrate hydrate is Disperse or suspend in water or an aqueous solution of guest molecules to form a slurry with high fluidity, and the above-mentioned problems are hardly caused. In the fourth embodiment, the temperature for cooling the aqueous solution of guest molecules in the first step is higher than 0 ° C. and 7 ° C. or lower, and the heating temperature of the hydrate slurry in the second step is 15 ° C. As described above, in a season in which the outside air temperature is 7 ° C. or less in one year (for example, in winter), the cooling device is not required or even if a cooling device is required. The first process can be performed using the thermal energy of the outside air while reducing the operation load of the outside, and in a season where the outside air temperature is 15 ° C. or higher (for example, spring or summer) Even if it is a case where it is not required or a heating apparatus is required, a 2nd process can be performed using the thermal energy of external air, reducing the operating load of the heating apparatus. This allows for relatively low energy consumption, efficient and economical gas collection and release that can withstand more realistic applications.

  In the method for collecting and releasing the gas according to the fourth aspect of the present invention, the temperature at which the aqueous solution is cooled in the first step is 15 ° C. or higher. In the spring and summer (for example, in the spring and summer), the thermal energy of the outside air is used to reduce the operating load of the cooling device without requiring a special cooling device or even when a cooling device is required. However, the aqueous solution can be cooled and energy can be saved. The same applies to the case where a gas cooling step for preliminarily cooling the gas to be collected is performed, and it is not necessary to require a special refrigeration apparatus or to reduce the operation load of the refrigeration apparatus.

  According to the fifth aspect of the present invention, the aqueous solution of the guest molecule cooled in the first step has a tetraisopentylammonium salt or two or more kinds of quaternary ammonium salts containing a tetraisopentylammonium salt as a solute. Since the hydrate formation temperature can be set to a preferable temperature, an aqueous solution of guest molecules and a slurry of hydrates that can correspond to various forms of the present invention (for example, the third form) are prepared. As a result, the effectiveness of the present invention can be enhanced.

If the aqueous solution of the guest molecule is an aqueous solution containing two or more kinds of quaternary ammonium salts containing tetraisopentylammonium salt or tetraisopentylammonium salt as a solute, the hydrate formation temperature is higher than 0 ° C or It is easy to adjust the temperature to 15 ° C. or higher, and therefore, a method for collecting and releasing the gas according to the present invention can be easily configured.
A typical example of a tetraisopentylammonium salt is tetraisopentylammonium bromide. The harmonic melting point of tetraisopentylammonium bromide hydrate is 30 ° C., and when cooling the aqueous solution (ie, when forming a hydrate), cooling at a temperature higher than 0 ° C. or 15 ° C. or higher. Since a hydrate can be generated by doing so, no particular cooling device is required, or even if a cooling device is required, the operating load of the cooling device can be reduced. It can contribute to savings and is efficient or economical.

In the present invention, the aqueous solution of the guest molecule is preferably an aqueous solution containing two or more kinds of quaternary ammonium salts containing a tetraisopentylammonium salt as a solute, but a quaternary other than the tetraisopentylammonium salt. One of the ammonium salts is preferably a tetra-n-butylammonium salt. Since tetra-n-butylammonium salt is relatively inexpensive and easily available, a method for collecting and releasing economically excellent gas can be constructed. (The same applies to the ninth, fourteenth and nineteenth embodiments.)
A typical example of a tetra n butyl ammonium salt is tetra n butyl ammonium bromide. If an aqueous solution containing tetraisopentylammonium bromide and tetra-n-butylammonium bromide as solutes, the hydrate formation temperature can be easily adjusted to a temperature higher than 0 ° C. or a temperature of 15 ° C. or higher. A method of collecting and releasing can be easily configured.

  According to the sixth aspect of the present invention, a part or all of the thermal energy used for cooling the aqueous solution of the guest molecule in the first step is a thermal energy extracted from a region that holds the cold in advance. Therefore, it is not necessary to create heat energy for cooling, which can contribute to energy saving.

  According to the seventh aspect of the invention, some or all of the thermal energy used to heat the hydrate slurry in the second step is transferred from the atmosphere or other external or ambient environment. Since it is thermal energy, it is not necessary to create heat energy for heating, which can contribute to energy saving.

  According to the eighth aspect of the present invention, since the temperature for cooling the aqueous solution in the first step is 15 ° C. or higher, for example, in a season in which the outside air temperature is 15 ° C. or higher in one year (for example, spring or summer). The aqueous solution can be cooled using the thermal energy of the outside air while reducing the operating load of the cooling device without requiring a special cooling device or even when a cooling device is required. it can. This allows for relatively low energy consumption, gas collection that is efficient and economical and thus can withstand more realistic applications. Further, since the heat exchange step that is indispensable in the first embodiment can be omitted, energy can be continuously saved when gas is collected and released.

  According to the ninth aspect of the present invention, the aqueous solution of the guest molecule contains tetraisopentylammonium salt or two or more kinds of quaternary ammonium salts including tetraisopentylammonium salt as a solute. Since the generation temperature can be set to a preferable temperature, an aqueous solution or hydrate slurry of guest molecules that can be used in the method according to the eighth embodiment can be prepared, and thus the effectiveness of the present invention can be improved. Can be increased.

  According to the 10th form of this invention, the apparatus with which the method which concerns on a 1st form is performed is realizable. In this case, each process of a 1st, 2nd and heat exchange is performed in a gas collection device, a gas discharge device, and a heat exchange device, respectively.

  According to the 11th form of this invention, the apparatus with which the method which concerns on a 2nd form is performed is realizable. In this case, the gas cooling process is performed in the cooling device.

  According to the 12th form of this invention, the apparatus with which the method which concerns on a 3rd form is performed is realizable.

  According to the thirteenth aspect of the present invention, it is possible to realize an apparatus in which the method according to the fourth aspect is executed.

  According to the fourteenth aspect of the present invention, an apparatus for executing the method according to the fifth aspect can be realized.

  According to the fifteenth aspect of the present invention, it is possible to realize an apparatus in which the method according to the sixth aspect is executed.

  According to the sixteenth aspect of the present invention, it is possible to realize the fifteenth aspect in which the “region holding cold heat in advance” is a storage facility for liquefied natural gas, a well, or a formation for storing groundwater. If the "cold area is pre-stored" is a liquefied natural gas storage facility, a well or a formation that stores groundwater, it can itself function as a cold source, so cool the aqueous solution of guest molecules Therefore, it is not necessary to provide a special device or facility for generating thermal energy for the purpose, and it is possible to contribute to saving of energy and facility cost.

  According to the seventeenth aspect of the present invention, an apparatus for executing the method according to the seventh aspect can be realized.

  According to the eighteenth aspect of the present invention, an apparatus for executing the method according to the eighth aspect can be realized. In this case, the first and second steps are executed in the gas collection device and the gas discharge device, respectively.

According to the nineteenth aspect of the present invention, an apparatus for executing the method according to the ninth aspect can be realized.
In addition, a guest molecule suitable in each form of the present invention is a tetraisopentylammonium salt or a tetraisopentylammonium salt and other quaternary ammonium salts (particularly, an alkylammonium salt typified by a tetra-nbutylammonium salt). It is.

  Hereinafter, the present invention will be described in detail by embodiments. The technical scope of the present invention is not limited by these embodiments, and can be implemented in various forms without changing the gist of the invention. Further, the technical scope of the present invention extends to an equivalent range.

[Embodiment 1]
FIG. 1 is an explanatory diagram for explaining the equipment configuration when an apparatus for collecting and releasing a gas according to the present invention is realized as a gas separation apparatus.
The gas separation device according to the present embodiment uses a hydrate containing a quaternary ammonium salt as a guest molecule to separate and collect the gas A from the mixed gas containing the gas A that is a component for collection. In addition, as shown in FIG. 1, the apparatus includes a gas cooling device 1, a gas collection device 3, a heat exchange device 5, and a gas release device 7.
An example of a quaternary ammonium salt is tetraisopentylammonium bromide (TiPAB), which may be a mixture of two or more types including tetraisopentylammonium bromide (TiPAB) and other quaternary ammonium salts. . As another quaternary ammonium salt, tetra-n-butylammonium bromide (TBAB) is preferable.
Hereinafter, the configuration of each device will be described in more detail.

<Gas cooling device>
The gas cooling device 1 preliminarily cools the mixed gas by exchanging heat between the introduced mixed gas and the cooled residual gas introduced from the gas collecting device 3.

<Gas collector>
The gas collection device 3 mixes an aqueous solution of a quaternary ammonium salt introduced from the heat exchange device 5 and a pre-cooled mixed gas, and cools it at a temperature higher than 0 ° C. to generate a hydrate containing the gas A. Gas A is collected from the mixed gas. The gas collection device 3 has a function of generating a hydrate slurry.
As shown in FIG. 2, the gas collector 3 having such a function includes a mixer 9, a hydrate slurry generator 11, and a separator 13. Hereinafter, each of these devices will be described.

[Mixer]
An aqueous solution of a quaternary ammonium salt (hereinafter sometimes simply referred to as “aqueous solution”) is supplied from the heat exchange device 5, and a mixed gas is supplied to the aqueous solution to mix them.
The supply of the mixed gas to the aqueous solution is relative, and this applies to the case where the aqueous solution is discharged toward the mixed gas as well as the case where the gas is discharged toward the aqueous solution. A typical example of the former is bubbling of gas from outside the region to the region where the aqueous solution exists. In that case, the bubble diameter is preferably as small as possible. One aspect of the mixer 9 for realizing this is that the mixer 9 is composed of a tank filled with an aqueous solution and the gas is dispersed in the aqueous solution as fine bubbles. In this case, it is preferable that the bubble diameter is small so that the gas-liquid contact area can be increased.
A typical example in the case of discharging the aqueous solution toward the latter, that is, the mixed gas, is spraying of the aqueous solution from the outside of the region to the region where the gas exists. As an aspect of the mixer 9 for realizing this, there is a type in which an aqueous solution is sprayed by a spray nozzle into a gas-filled container and brought into contact with the gas to dissolve the gas in the aqueous solution.
In both the former and the latter cases, it is preferable that the gas supply to the aqueous solution is performed by a technique for further increasing the contact area between the gas and the aqueous solution.

  After the mixed gas is mixed with the aqueous solution of the quaternary ammonium salt by the mixer 9, the mixed fluid is sent to the hydrate slurry generator 11 by a pump.

[Hydrate slurry generator]
The hydrate slurry generator 11 has a cooling function, and cools the aqueous solution containing the quaternary ammonium salt solution mixed with the mixer 9 and the mixed gas to bring the gas A and the quaternary ammonium salt into the guest. A hydrate slurry is formed by dispersing or suspending the hydrate in an aqueous solution or water. The cooling function preferably includes a heat exchanger that supplies and cools the refrigerant.

In the hydrate slurry generator 11, the cooling temperature for cooling the aqueous solution is higher than 0 ° C. That is, the temperature of the slurry to be generated is set to a temperature higher than 0 ° C. If the cooling temperature is cooled to a temperature higher than 0 ° C., a cooling tower that exchanges heat between the refrigerator or the outside air and cold water can be used as an apparatus used to supply the refrigerant. A refrigerant can be supplied. In particular, when TiPAB is used as a quaternary ammonium salt, a hydrate can be generated at 15 ° C. or higher, so it is possible to use the thermal energy of the outside air, and a more economical method can be selected.
The hydrate slurry generator 11 is preferably provided with a stirring mechanism.

In the hydrate slurry generator 11, a hydrate is generated by cooling, and the generated hydrate is stirred to generate a hydrate slurry in which hydrate particles are dispersed in an aqueous solution. Moreover, since supercooling is cancelled | released rapidly by cooling while stirring aqueous solution, a hydrate slurry can be produced | generated efficiently.
Further, in the hydrate slurry generator 11, there is a remaining portion of the mixed gas that has not been collected by the hydrate, but this is separated from the hydrate slurry by the separator 13 described later as the residual gas. And is discharged from the gas collection device 3.

[Separator]
The separator 13 receives the supply of the hydrate slurry and the unreacted residual gas from the hydrate slurry generator 11 and separates the unreacted residual gas.
The type of the separator 13 is arbitrary. For example, a cyclone separator or the like can be used. However, in order to minimize the mixing of slurry droplets into the separated residual gas, for example, a collision separation type mist separator is also used. It is desirable to use.
Since the residual gas separated by the separator 13 is cooled, it has cold heat. Therefore, the residual gas is sent to the gas cooling device 1 in order to use the cold heat of the residual gas. The residual gas sent to the gas cooling device 1 is used in the gas cooling device 1 to exchange heat with the mixed gas and cool the mixed gas in advance.

<Heat exchange device>
The heat exchange device 5 introduces the hydrate slurry generated by the gas collection device 3, heat-exchanges the introduced hydrate slurry and the aqueous solution introduced from the gas discharge device 7, and the heated slurry and To produce a cooled aqueous solution.
The cooled aqueous solution is supplied to the gas collection device 3 by a first supply device (specifically, for example, a pipe and a pump) (not shown). Further, the heated slurry is supplied to the gas release device 7 by a second supply device (specifically, for example, a pipe and a pump) (not shown).

<Gas release device>
The gas release device 7 has a heating function. The hydrate slurry heated by the heat exchange device 5 is introduced, and this is further heated to melt the hydrate to produce an aqueous solution. The gas A collected in is released. As a heating function, it is preferable to provide a heat exchanger that supplies and heats a heat medium.
The mixed fluid composed of the gas A and the aqueous solution is introduced into the second separator, separated into the aqueous solution and the gas A, and the aqueous solution is sent to the heat exchange device 5. The separated gas A is discharged and appropriately stored in a storage tank or the like, or introduced into the next processing process.

FIG. 3 schematically shows the function of each device constituting the gas separation device and the state of the gas, aqueous solution, and slurry passing through each device. Hereinafter, a method of separating the gas A from the mixed gas by the gas separation device configured as described above will be described with reference to FIG.
A mixed gas containing gas A, which is a component for collection, is introduced into the gas cooling device 1, and heat exchange is performed between the mixed gas and the cooled residual gas introduced from the gas collecting device 3 (see the broken line arrows in FIG. 3). The mixed gas is cooled in advance. Examples of the gas A as the target component to be separated include carbon dioxide.

The mixed gas cooled in the gas cooling device 1 is introduced into the gas collecting device 3, mixed with the aqueous solution of the quaternary ammonium salt by the mixer 9, and dissolved in the aqueous solution.
The After the mixed gas is dissolved in the aqueous solution of the quaternary ammonium salt by the mixer 9, the mixed fluid is sent to the hydrate slurry generator 11 by a pump. In the hydrate slurry generator 11, the mixed fluid is cooled at a temperature higher than 0 ° C. by heat exchange with a refrigerant or the like to generate a hydrate containing gas A and a quaternary ammonium salt as a guest. By stirring in the hydrate slurry generator 11, a hydrate slurry in which hydrate particles are dispersed in an aqueous solution is generated.
The hydrate slurry and unreacted residual gas generated in the hydrate slurry generator 11 are supplied to the separator 13 to separate the hydrate slurry and unreacted residual gas (see FIG. 2). The separated hydrate slurry is introduced into the heat exchange device 5. On the other hand, the residual gas separated by the separator 13 is introduced into the gas cooling device 1 and used so as to cool the mixed gas in advance.
In addition, when the gas A remains in the residual gas, it can be recirculated and used as a mixed gas, for example, until the residual amount becomes a certain amount or less.

It is preferable that a part or all of the thermal energy used for cooling the mixed fluid in the hydrate slurry generator 11 is the thermal energy extracted from the region in which the cold is previously held.
Typical examples of the area in which cold heat is stored in advance include a heat storage tank (or cold storage tank), a heat storage device (or cold storage device), a container that stores a heat storage material (or cold storage material), and the like. Includes wells, geological formations or water storage tanks that store groundwater, liquefied natural gas storage facilities or transport facilities (including transport pipes), air (or outside air), or external or surrounding environments. Since the thermal energy taken out from the region where the cold is previously held is used, it is not necessary to particularly create the thermal energy for cooling the mixed fluid, which can contribute to energy saving.

  The hydrate slurry separated by the separator 13 is introduced into the heat exchange device 5 (see FIG. 3). In the heat exchange device 5, heat exchange is performed between the introduced hydrate slurry and the aqueous solution introduced from the gas release device 7 (see FIG. 3). Since the temperature of the hydrate slurry is lower than that of the aqueous solution, the temperature rises due to heat exchange with the aqueous solution to become a heated hydrate slurry, and conversely, the aqueous solution is cooled to become a cooled aqueous solution.

  The heated hydrate slurry is introduced into the gas release device 7 and further heated in the gas release device 7 (see FIG. 3). By this heating, the hydrate melts and the gas A collected in the hydrate is released. By releasing the gas A, the gas release device 7 has a mixed fluid composed of the gas A and the aqueous solution, and this mixed fluid is introduced into a second separator (not shown), and the aqueous solution and the gas A are converted into the aqueous solution and the gas A. They are separated (see FIG. 3). The separated aqueous solution is sent to the heat exchange device 5, and the separated gas A is discharged and stored in a storage tank or the like as appropriate, or introduced into the next treatment process.

Preferably, some or all of the thermal energy used to heat the hydrate slurry in the gas release device is thermal energy transferred from the atmosphere or other external or ambient environment.
Thereby, it is not necessary to create heat energy for heating in particular, which can contribute to energy saving.

According to the above embodiment, gas is collected using a hydrate containing a quaternary ammonium salt as a guest molecule, and the gas is separated by releasing the collected gas. The recovery cycle can be realized efficiently or economically.
In the present embodiment, the gas is collected using a hydrate containing a quaternary ammonium salt as a guest molecule, and the collected gas is released to separate the gas, and the heat exchange device 5 This realizes a cycle of exchanging heat between the hydrate slurry and the aqueous solution to reduce energy consumption, and is a gas separation device that can withstand practical applications.

  In the above embodiment, the mixed gas and the aqueous solution are mixed by the mixer 9 separately provided in the gas collecting device 3, but the mixer 9 is omitted and the hydrate slurry generator 11 is mixed. The aqueous solution and the mixed gas may be mixed by supplying the mixed gas to the aqueous solution.

[Embodiment 2]
FIG. 4 is an explanatory diagram for explaining the equipment configuration when the apparatus for collecting and releasing a gas according to the present invention is realized as a gas separation apparatus.
As in the first embodiment, the gas separation device according to the second embodiment uses a hydrate containing a quaternary ammonium salt as a guest molecule, and uses a mixed gas containing a gas A that is a collection object. It is an apparatus for separating and collecting the gas A and releasing the collected gas A. However, the difference from the first embodiment is that, as shown in FIG. 4, the gas cooling device and the heat exchange device that existed as the device configuration of the first embodiment are omitted, and the gas collection device 15 has a temperature of 15 ° C. or higher. The point is that the aqueous solution of the guest molecule is selected so that the aqueous solution can be cooled at a temperature to form a hydrate.

Examples of the aqueous solution of the quaternary ammonium salt selected in Embodiment 2 include an aqueous solution of tetraisopentylammonium bromide (TiPAB) or an aqueous solution of two or more kinds of quaternary ammonium salts containing tetraisopentylammonium bromide. preferable. This is because the tetraisopentylammonium bromide has a harmonic melting point of 30 ° C., and it is easy to adjust the hydrate formation temperature to a temperature of 15 ° C. or higher.
One of the quaternary ammonium salts other than tetraisopentylammonium bromide is preferably tetra-n-butylammonium bromide. Since tetra-n-butylammonium bromide is relatively inexpensive and easy to obtain, by properly blending tetraisopentylammonium bromide and tetra-n-butylammonium bromide, the hydrate formation temperature can be raised to 15 ° C or higher. A method of collecting and releasing a gas that is easy to adjust and economically excellent can be configured.
Hereinafter, the configuration of each device according to the second embodiment will be described in detail. Since each device is basically the same as that described in the first embodiment, whether each device in the second embodiment is the same as that shown in the first embodiment will be described below. This will be described if there are any differences.

<Gas collector>
The gas collection device 15 is mixed by mixing an aqueous solution of a quaternary ammonium salt introduced from the gas release device 17 and a mixed gas, cooling at a temperature higher than 15 ° C., and generating a hydrate containing the gas A. Gas A is collected from the gas. The gas collection device 15 has a function of generating a hydrate slurry.
The gas collection device 15 having such a function includes a mixer, a hydrate slurry generator, and a separator as described in the first embodiment (see FIG. 2).

[Mixer]
This is the same as that shown in the first embodiment.

[Hydrate slurry generator]
The hydrate slurry generator has a cooling function, and cools an aqueous solution containing an aqueous solution of a quaternary ammonium salt mixed with a mixer and a mixed gas, and contains gas A and a quaternary ammonium salt as a guest. Inclusion hydrate is produced. This is the same as in the first embodiment.

In the hydrate slurry generator of the second embodiment, the cooling temperature for cooling the aqueous solution is higher than 15 ° C. That is, the temperature of the slurry to be generated is set to a temperature higher than 15 ° C. If the cooling temperature is set to a temperature higher than 15 ° C., for example, in a season in which the outside air temperature is 15 ° C. or more (for example, spring or summer) in one year, a special cooling device is required for the aqueous solution. Even if it is a case where a cooling device is required, the aqueous solution can be cooled using the thermal energy of the outside air while reducing the operating load of the cooling device.
The hydrate slurry generator is preferably provided with a stirring mechanism.
In the hydrate slurry generator, clathrate hydrate is produced by cooling, and stirring is performed to produce a hydrate slurry in which clathrate hydrate particles are dispersed in an aqueous solution.

[Separator]
The separator is the same as that of the first embodiment.

<Gas release device>
The gas discharge device 17 is the same as that in the first embodiment.

FIG. 5 schematically shows the function of each device constituting the gas separation device and the state of the gas, aqueous solution, and slurry passing through each device. Hereinafter, a method of separating the gas A from the mixed gas by the gas separation device configured as described above will be described with reference to FIG.
Gas A, which is the purpose of collection, for example, a mixed gas containing carbon dioxide is introduced into the gas collecting device 15 (see FIG. 5), mixed with an aqueous solution of a quaternary ammonium salt by a mixer, and the mixed gas is dissolved in the aqueous solution. To do.
After the mixed gas is dissolved in the aqueous solution of the quaternary ammonium salt by the mixer, the mixed fluid is sent to the hydrate slurry generator by a pump. In the hydrate slurry generator, the mixed fluid is cooled at a temperature higher than 15 ° C. to produce an clathrate hydrate containing gas A and a quaternary ammonium salt as a guest. By stirring in the generator, a hydrate slurry in which clathrate hydrate particles are dispersed in an aqueous solution is generated.
The hydrate slurry generated by the hydrate slurry generator and the unreacted residual gas are supplied to the separator, and the hydrate slurry and the unreacted residual gas are separated. When the gas A remains in the residual gas, it is recirculated and used as a mixed gas, for example, until the residual amount becomes a certain amount or less.
The separated hydrate slurry is introduced into the gas release device 17 and further heated in the gas release device 17 (see FIG. 5). By this heating, the hydrate melts and the gas A collected in the hydrate is released. When the gas A is released, a mixed fluid composed of the gas A and the aqueous solution exists in the gas release device 17, and this mixed fluid is introduced into a second separator (not shown), and the aqueous solution and the gas A are converted into the aqueous solution and the gas A. To be separated. The separated aqueous solution is sent to a heat exchange device, and the separated gas A is discharged and stored in a storage tank or the like as appropriate, or introduced into the next treatment process.

In Embodiment 2, by using the above-mentioned aqueous solution of the quaternary ammonium salt, the hydrate formation temperature can be easily adjusted to a temperature of 15 ° C. or more, and the following effects are obtained.
That is, according to the second embodiment, the temperature for cooling the aqueous solution in the gas collecting device 15 is 15 ° C. or higher, and thus, for example, in a season in which the outside air temperature is 15 ° C. or higher in one year (for example, spring or summer). The aqueous solution can be cooled using the thermal energy of the outside air while reducing the operating load of the cooling device without requiring a special cooling device or even when a cooling device is required. it can. This allows for relatively low energy consumption, gas collection that is efficient and economical and thus can withstand more realistic applications. In addition, since the heat exchange device that is indispensable in the first embodiment can be omitted, energy can be continuously saved when gas is collected and released.

Using the gas collection device and the gas release device shown in FIG. 34, an experiment was conducted to separate the gas from a mixed gas containing a specific gas.
The experimental method, the test aqueous solution used, and the test gas mixture are as follows.

[Gas separation experiment method]
A hydrate slurry generator that also serves as a mixer is filled with an aqueous solution of a quaternary ammonium salt (hereinafter referred to as a test aqueous solution). The mixed gas was introduced into the hydrate slurry generator filled with this aqueous test solution, and the valve provided on the mixed gas supply pipe was closed while the pressure was increased to 0.5 MPa at 30 ° C., and the heat exchange part of the hydrate slurry generator The refrigerant is supplied to the hydrate slurry generator and cooled from 30 ° C. to the test temperature (15 ° C., 20 ° C.) while stirring the liquid phase part inside the hydrate slurry generator.
A hydrate containing a quaternary ammonium salt and a gas is generated by cooling, and the pressure inside the hydrate slurry generator is gradually reduced by collecting the gas.
After the pressure drop inside the hydrate slurry generator was completed, the residual gas remaining was extracted from the hydrate slurry generator, and the gas composition of the residual gas was measured by a gas chromatograph. In addition, the hydrate slurry was extracted from the hydrate slurry generator, introduced into the gas discharge device, and the hydrate slurry was melted by heating the hydrate slurry by supplying a heat medium to the heat exchange unit, and collected. The gas is released. Then, the released gas (referred to as recovered gas) was extracted, and the gas composition of the recovered gas was measured by a gas chromatograph.

[Test aqueous solution]
(1) Tetraisopentyl ammonium bromide (TiPAB) 5 wt% aqueous solution (2) Tetraisopentyl ammonium bromide (TiPAB) 2.5 wt% mixed aqueous solution of tetra n butyl ammonium bromide (TBAB) 2.5 wt% (3 ) As a comparative example, a mixed aqueous solution of tetra n-butylammonium bromide (TBAB) 5 wt%

[Test gas mixture]
Mixed gas containing 5% carbon dioxide (for example, mixed gas simulating blast furnace gas)
The separation target gas is carbon dioxide.

The experimental results are shown in Table 1.

As shown in Table 1, tetraisopentylammonium bromide (TiPAB) 5 wt% aqueous solution or tetraisopentylammonium bromide (TiPAB) 2.5 wt% and tetranbutylammonium bromide (TBAB) 2.5 wt% mixed aqueous solution It was confirmed that carbon dioxide can be selectively collected from the mixed gas and concentrated by increasing the concentration of carbon dioxide in the recovered gas by collecting and releasing the target gas.
It was also confirmed that the lower the cooling temperature, the more the target gas can be collected.
On the other hand, when the aqueous solution of tetra n-butylammonium bromide (TBAB) 5 wt% of the comparative example was used, the concentration of carbon dioxide in the recovered gas was slightly higher than the concentration of the test gas mixture before the experiment due to the dissolution of carbon dioxide in the aqueous solution. Although the temperature was higher, under the conditions of cooling temperature of 20 ° C or 15 ° C, tetra n-butylammonium bromide hydrate was not formed, and could the target gas be collected by forming the hydrate? I was not able to confirm clearly whether it was able to collect.

It is explanatory drawing of the gas separation apparatus which concerns on Embodiment 1 of this invention. FIG. 2 is a detailed explanatory diagram of a part of the gas separation device shown in FIG. 1. It is explanatory drawing of the gas separation method in Embodiment 1 of this invention. It is explanatory drawing of the gas separation apparatus which concerns on Embodiment 2 of this invention. It is explanatory drawing of the gas separation method in Embodiment 2 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Gas cooling device 3 Gas collection device 5 Heat exchange device 7 Gas discharge device 9 Mixer 11 Hydrate slurry generator 13 Separator 15 Gas collection device 17 Gas discharge device

Claims (10)

A method of collecting and releasing gas using a hydrate containing a quaternary ammonium salt as a guest molecule,
The aqueous solution of the guest molecule is brought into contact with a gas and cooled at a temperature higher than 0 ° C. to generate a hydrate that collects the gas, and the hydrate is dispersed or suspended in the aqueous solution or water. A first step of generating a slurry comprising:
The slurry produced in the first step is heated to melt the hydrate therein, thereby releasing the gas collected by the hydrate and producing an aqueous solution of the guest molecule. 2 processes,
A part or all of the slurry generated in the first step and a part or all of the aqueous solution of the guest molecules generated in the second step are subjected to heat exchange, and the guest molecules cooled by the heat exchange The aqueous solution is used as part or all of the aqueous solution of guest molecules in the first step, and the slurry heated by the heat exchange is used as part or all of the slurry in the second step. A method of collecting and releasing a characteristic gas.   The first step has a step of mixing or stirring the aqueous solution of the guest molecule and the gas and cooling at a temperature of 7 ° C. or less, and the second step is for the slurry generated in the first step to be 15%. The method for collecting and releasing a gas according to claim 1, further comprising a step of heating at a temperature of not lower than ° C.   The method for collecting and releasing a gas according to claim 1, wherein the first step includes a step of mixing or stirring the aqueous solution of the guest molecule and the gas and cooling at a temperature of 15 ° C. or more. .   The aqueous solution of the guest molecule contains two or more kinds of quaternary ammonium salts containing tetraisopentylammonium salt or tetraisopentylammonium salt as a solute. A method of collecting and releasing gas.   The thermal energy used for cooling the aqueous solution of the guest molecule in the first step is part or all of thermal energy extracted from a region in which cold is held in advance. 4. A method for collecting and releasing the gas according to any one of 4 above.   A part or all of the thermal energy used to heat the hydrate slurry in the second step is thermal energy transferred from the atmosphere or other external or ambient environment. A method for collecting and releasing the gas according to any one of 1 to 5. An apparatus for collecting and releasing gas using a hydrate containing a quaternary ammonium salt as a guest molecule,
  An aqueous solution of the guest molecule is brought into contact with a gas and cooled at a temperature higher than 0 ° C., thereby generating a hydrate that collects the gas, and the hydrate is dispersed or suspended in the aqueous solution or water. A gas collector for producing a slurry,
  A gas release device that heats the slurry generated in the gas collector, melts hydrates in the slurry, thereby releasing a gas, and generating an aqueous solution of the guest molecule;
  A heat exchange device that performs heat exchange between a part or all of the aqueous solution of the guest molecules generated in the gas release device and a part or all of the slurry generated in the gas collector;
  A first supply device for supplying an aqueous solution of the guest molecules cooled by the heat exchange device to the gas collection device;
  And a second supply device for supplying the slurry heated by the heat exchange device to the gas release device, and a device for collecting and releasing the gas.   8. The gas according to claim 7, wherein the aqueous solution of the guest molecule contains tetraisopentylammonium salt or two or more kinds of quaternary ammonium salt containing tetraisopentylammonium salt as a solute. Emitting device. Part or all of the thermal energy used for cooling the aqueous solution of the guest molecules in the gas collector is thermal energy extracted from a storage facility for liquefied natural gas, a well, or a formation for storing groundwater. An apparatus for collecting and releasing a gas according to claim 7 or 8. Part or all of the thermal energy used to heat the hydrate slurry in the gas release device is thermal energy transferred from the atmosphere or other external or ambient environment. Item 10. A device for collecting and releasing the gas according to any one of Items 7 to 9.

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