JP2014005156A - Ammonia purification system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ammonia purification system that can purify ammonia efficiently with low energy consumption in a simplified method.SOLUTION: In an ammonia purification system 100, a first adsorption tower 31 and a second adsorption tower 32 adsorb and remove impurities contained in crude ammonia delivered from a raw material storage tank 1. The first adsorption tower 31 and the second adsorption tower 32 have structures in which tower top adsorption layers 311, 321, first intermediate adsorption layers 312, 322, second intermediate adsorption layers 313, 323 and tower bottom adsorption layers 314, 324 are stacked in an ammonia flow direction, respectively. A condenser 4 separates and removes highly volatile impurities as gas phase components by condensing and separating ammonia delivered from the first adsorption tower 31 and the second adsorption tower 32 into gas phase components and liquid phase components.

Description

  The present invention relates to an ammonia purification system for purifying crude ammonia.

  In a semiconductor manufacturing process and a liquid crystal manufacturing process, high-purity ammonia is used as a processing agent used for producing a nitride film. Such high-purity ammonia can be obtained by purifying crude ammonia to remove impurities.

  Crude ammonia contains hydrogen, nitrogen, oxygen, argon, carbon monoxide, carbon dioxide and other low-boiling gases, hydrocarbons and other organic compounds, moisture, etc. as impurities. The purity of ammonia is about 98 to 99% by weight.

  Generally, organic compounds such as hydrocarbons contained in crude ammonia are mainly those having 1 to 4 carbon atoms, but when producing hydrogen gas used as a raw material for ammonia synthesis, the oil content in the cracking gas When separation is insufficient, or when the oil is contaminated with pump oil from pumps during production, hydrocarbons having a high boiling point and a large molecular weight may be mixed. In addition, if ammonia contains a large amount of moisture, the function of a semiconductor or the like manufactured using this ammonia may be greatly reduced, and the moisture in ammonia needs to be reduced as much as possible.

  Depending on the type of process in which ammonia is used in the semiconductor manufacturing process and the liquid crystal manufacturing process, the effect of impurities in ammonia varies, but the purity of ammonia is 99.9999% by weight or more (each impurity concentration is 100 ppb or less). Preferably, it is required to be about 99.99999% by weight. In recent years, a moisture concentration of less than 30 ppb has been demanded for the production of a light emitter such as gallium nitride.

  Known methods for removing impurities contained in crude ammonia include a method for removing impurities by adsorption using an adsorbent such as silica gel, synthetic zeolite, and activated carbon, and a method for removing impurities by distillation. A method of combining adsorption and distillation is also known.

  For example, Patent Document 1 discloses a first distillation column that removes low-volatile impurities from liquid crude ammonia, and impurities (mainly moisture) contained in gaseous ammonia derived from the first distillation column. An ammonia purification system is disclosed that includes an adsorption tower that adsorbs and removes with an adsorbent, and a second distillation tower that removes highly volatile impurities from gaseous ammonia derived from the adsorption tower.

  Patent Document 2 discloses a method for purifying ammonia that obtains high-purity ammonia by combining a moisture adsorption tower, a hydrocarbon adsorption tower, and a distillation tower. In Patent Document 3, after removing impurities having a low boiling point in a distillation column, ammonia is removed from gaseous ammonia in an adsorption column, and oxygen is separated and removed in a catalyst part to obtain high purity ammonia. A purification method is disclosed.

JP 2006-206410 A Special table 2008-505830 gazette JP 2005-162546 A

  In the technology for purifying ammonia disclosed in Patent Documents 1 to 3, impurities contained in the crude ammonia are removed by adsorption with an adsorption tower or by a catalytic reaction in the catalyst section, and further distilled off with a distillation tower. And the ammonia is purified. In the ammonia purification methods disclosed in Patent Documents 1 to 3, the purified gaseous ammonia derived from the distillation tower is condensed and recovered as liquid ammonia. That is, in the method for purifying ammonia disclosed in Patent Documents 1 to 3, the liquid ammonia purified by adsorption and distillation removal of impurities contained in the crude ammonia and further condensed to obtain purified ammonia is obtained. However, it cannot be said that it has been simplified, and a lot of energy is required to purify ammonia.

  Accordingly, an object of the present invention is to provide an ammonia purification system capable of purifying ammonia by a simplified method and efficiently purifying ammonia while suppressing energy consumption.

The present invention provides an ammonia purification system for purifying crude ammonia containing impurities.
Storage means for storing crude ammonia and deriving the stored crude ammonia;
Impurities contained in the crude ammonia derived from the storage means are purified by adsorbing and removing with an adsorbent selected from activated carbon, hydrophilic zeolite, hydrophobic zeolite, silica gel and activated alumina. A suction means for deriving,
A first adsorbent layer comprising a first adsorbent;
A plurality of second adsorbent layers including a second adsorbent of a type different from the first adsorbent;
A third adsorbent layer containing a third adsorbent of a type different from the second adsorbent, and an adsorbing means having one or a plurality of adsorbing portions laminated in the flow direction of the crude ammonia;
By separating the purified ammonia derived from the adsorption means into a gas phase component and a liquid phase component, the highly volatile impurities are separated and removed as a gas phase component and purified as a liquid phase component. And a partial pressure reduction means for obtaining the liquid ammonia.

The ammonia purification system of the present invention further comprises a vaporization means for vaporizing a part of the liquid crude ammonia derived from the storage means, and for deriving gaseous ammonia.
The adsorption means adsorbs and removes impurities contained in gaseous ammonia derived from the vaporization means by the adsorption unit.

In the ammonia purification system of the present invention, the first adsorbent is an adsorbent having a high adsorbability for water,
The second adsorbent is an adsorbent having a high adsorbing ability for an organic compound having less than 5 carbon atoms,
The third adsorbent is an adsorbent having high adsorbability for an organic compound having 5 or more carbon atoms and water.

  Further, in the ammonia purification system of the present invention, the adsorbing portion is arranged such that the first adsorbent layer, the plurality of second adsorbent layers, and the third adsorbent are arranged from the upstream side to the downstream side in the flow direction of the crude ammonia. The layers are laminated in this order.

Moreover, in the ammonia purification system of the present invention, the adsorption means has a plurality of the adsorption parts,
The plurality of suction portions are connected in series or in parallel.

  According to the present invention, the ammonia purification system is a system for purifying crude ammonia containing impurities, and includes a storage means, an adsorption means, and a partial reduction means. The storage means stores the crude ammonia and derives the stored crude ammonia. The adsorbing means is means for adsorbing and purifying impurities contained in the crude ammonia derived from the storage means, and the first adsorbent layer, the plurality of second adsorbent layers, and the third adsorbent layer are: It has an adsorbing part laminated in the flow direction of crude ammonia. In the adsorption part of the adsorption means, the first adsorbent layer is a layer containing the first adsorbent, the second adsorbent layer is a layer containing the second adsorbent, and the third adsorbent layer is the third adsorbent. It is a layer that contains. Here, the first adsorbent, the second adsorbent, and the third adsorbent are adsorbents selected from activated carbon, hydrophilic zeolite, hydrophobic zeolite, silica gel, and activated alumina, respectively.

  The ammonia derived from the adsorbing means having the adsorbing portion in which at least the first adsorbent layer, the plurality of second adsorbent layers, and the third adsorbent layer are stacked is supplied to the partial reduction means. The fractionation means separates and removes highly volatile impurities as gas phase components by separating ammonia separated from the adsorption means into gas phase components and liquid phase components, and purifies them as liquid phase components. Liquid ammonia is obtained.

  In the ammonia purification system of the present invention, an adsorbent layer including a first adsorbent, a second adsorbent, and a third adsorbent, which is an adsorbent selected from activated carbon, hydrophilic zeolite, hydrophobic zeolite, and silica gel is laminated. Since the adsorbing part adsorbs and removes impurities contained in the crude ammonia, impurities (mainly water and organic compounds) contained in the crude ammonia can be efficiently adsorbed and removed. Then, the partial reduction means reduces the ammonia derived from the adsorption means and separates it into a gas phase component and a liquid phase component, so that the volatilization of hydrogen, nitrogen, oxygen, argon, carbon monoxide, carbon dioxide, etc. High-impurity impurities can be separated and removed as a gas phase component, and liquid ammonia purified as a liquid phase component can be obtained. Therefore, in the ammonia purification system of the present invention, ammonia can be purified by a simplified method without performing distillation with reflux as in the prior art, and energy consumption is suppressed and ammonia is efficiently used. Can be purified.

  According to the invention, the ammonia purification system further includes vaporization means. This vaporization means vaporizes a part of the liquid crude ammonia derived from the storage means, and derives gaseous ammonia. Then, the adsorbing means causes impurities contained in gaseous ammonia derived from the vaporizing means to be absorbed by an adsorbing portion in which the first adsorbent layer, the plurality of second adsorbent layers, and the third adsorbent layer are stacked. Remove by adsorption. The vaporization means is configured to vaporize a part of the liquid crude ammonia derived from the storage means and derive gaseous ammonia. Therefore, the low volatility impurities contained in the crude ammonia ( For example, moisture, hydrocarbons having 6 or more carbon atoms, etc.) remain in the liquid phase, and gaseous ammonia in which impurities with low volatility are reduced can be derived.

  According to the invention, the first adsorbent contained in the first adsorbent layer in the adsorbing part of the adsorbing means is an adsorbent having a high adsorbability for water and is contained in the second adsorbent layer. The second adsorbent is an adsorbent having high adsorbability for organic compounds having less than 5 carbon atoms, and the third adsorbent contained in the third adsorbent layer is an organic compound having 5 or more carbon atoms and water On the other hand, it is an adsorbent having a high adsorption capacity. Thus, the impurities contained in the crude ammonia are adsorbed and removed by the adsorbing layer in which adsorbent layers having different adsorbing capacities for water, organic compounds having less than 5 carbon atoms, and organic compounds having 5 or more carbon atoms are stacked. Impurities (mainly water and organic compounds) contained in the crude ammonia can be efficiently adsorbed and removed.

  According to the present invention, the adsorbing portion of the adsorbing means includes the first adsorbent layer, the second adsorbent layer, and the third adsorbent layer in this order from the upstream side to the downstream side in the flow direction of the crude ammonia. Are stacked. The crude ammonia supplied to the adsorption means flows in the order of the first adsorbent layer, the second adsorbent layer, and the third adsorbent layer in the adsorption section. Since the first adsorbent layer contains the first adsorbent that has a high adsorbability for water, the crude ammonia flowing through the adsorbing portion is first adsorbed and removed by the majority of water in the first adsorbent layer. Will be. As a result, the second adsorbent layer and the third adsorbent layer disposed downstream of the first adsorbent layer in the flow direction of ammonia sufficiently exhibit the ability to adsorb organic compounds. It is possible to improve the adsorption / removability of impurities from the substrate.

  According to the invention, the adsorbing means has a plurality of adsorbing portions in which the first adsorbent layer, the second adsorbent layer, and the third adsorbent layer are stacked. The plurality of suction portions are connected in series or in parallel. When the adsorbing means has a plurality of adsorbing portions connected in series, it is possible to improve the adsorbing and removing ability for impurities contained in the crude ammonia. In addition, when the adsorption means has a plurality of adsorption parts connected in parallel, the crude ammonia derived from the storage means should be introduced separately from each other for the plurality of adsorption parts connected in parallel. Therefore, during the adsorption removal by one adsorption unit, the other adsorption unit used can be regenerated so that the adsorption removal operation can be performed again by the other adsorption unit.

It is a figure which shows the structure of the ammonia purification system 100 which concerns on 1st Embodiment of this invention. It is a figure which shows the structure of the ammonia purification system 150 which concerns on 2nd Embodiment of this invention. It is a figure which shows the structure of the ammonia purification system 200 which concerns on 3rd Embodiment of this invention. It is a figure which shows the structure of the ammonia purification system 300 which concerns on 4th Embodiment of this invention. It is a figure which shows the structure of the ammonia purification system 400 which concerns on 5th Embodiment of this invention.

  FIG. 1 is a diagram showing a configuration of an ammonia purification system 100 according to the first embodiment of the present invention. The ammonia purification system 100 of this embodiment is a system for purifying liquid crude ammonia containing impurities. The ammonia purification system 100 includes a raw material storage tank 1 that is a storage means, a vaporizer 2 that is a vaporization means, an adsorption unit 3 that is an adsorption means, a condenser 4 that is a partial reduction means, and a recovery tank 5.

  The raw material storage tank 1 stores crude ammonia. In the present embodiment, the crude ammonia stored in the raw material storage tank 1 has a purity of 99% by weight or more, preferably a purity of 99.0 to 99.9% by weight.

  The raw material storage tank 1 is not particularly limited as long as it is a heat insulating container having pressure resistance and corrosion resistance. The raw material storage tank 1 stores crude ammonia as liquid ammonia and is controlled so as to have a predetermined temperature and pressure. The raw material storage tank 1 has a cylindrical internal space, and in the state where liquid crude ammonia is stored in the internal space, a gas phase is formed in the upper part of the raw material storage tank 1, and a liquid phase is formed in the lower part. Is formed.

  The raw material storage tank 1 communicates with the raw material storage tank 1 and the outside, and highly volatile impurities distributed in the gas phase (for example, hydrogen, nitrogen, oxygen, argon, carbon monoxide, carbon dioxide, etc.) are externally supplied. An exhaust pipe 80 serving as a flow path for discharging is connected. The exhaust pipe 80 is provided with an exhaust valve 801 that opens or closes the flow path in the exhaust pipe 80. The ammonia purification system 100 according to the present embodiment is configured such that a discharge operation for discharging and removing highly volatile impurities from the crude ammonia stored in the raw material storage tank 1 can be performed by opening the exhaust valve 801. Yes. Specifically, after liquid crude ammonia is stored in the raw material storage tank 1 for 0.5 to 3 days, the exhaust valve 801 is opened for 10 to 300 minutes. Thereby, highly volatile impurities in the crude ammonia distributed in the gas phase formed in the raw material storage tank 1 can be discharged through the exhaust pipe 80.

  Crude ammonia stored in the raw material storage tank 1 is led to the vaporizer 2. When crude ammonia is derived from the raw material storage tank 1 to the vaporizer 2, it is derived as liquid crude ammonia from the liquid phase formed in the raw material storage tank 1. Crude ammonia as a raw material may have a large variation in impurity concentration between product lots. As described above, when crude ammonia having a large impurity concentration variation is derived from the gas phase of the raw material storage tank 1, the component composition in the gas phase varies greatly and the purity of the finally purified ammonia varies greatly. May occur. Since the ammonia purification system 100 of the present embodiment is configured such that liquid crude ammonia is derived from the liquid phase of the raw material storage tank 1, when crude ammonia having a large variation in impurity concentration is used as the raw material, In this case, it is possible to prevent a large variation in the purity of the finally purified ammonia.

  A first pipe 81 is connected between the raw material storage tank 1 and the vaporizer 2, and liquid crude ammonia derived from the raw material storage tank 1 flows through the first pipe 81 and is supplied to the vaporizer 2. Is done. The first pipe 81 is provided with a first valve 811 that opens or closes the flow path in the first pipe 81. When supplying the liquid crude ammonia to the vaporizer 2, the first valve 811 is opened, and the liquid crude ammonia flows in the first pipe 81 from the raw material storage tank 1 toward the vaporizer 2.

  The vaporizer 2 vaporizes a part of the liquid crude ammonia derived from the raw material storage tank 1. That is, the vaporizer 2 heats liquid crude ammonia, vaporizes it at a predetermined vaporization rate, separates it into a gas phase component and a liquid phase component, and derives gaseous ammonia. Since the vaporizer 2 vaporizes a part of the liquid crude ammonia, low-volatile impurities (for example, moisture, hydrocarbons having 6 or more carbon atoms) contained in the crude ammonia remain in the liquid phase, Gaseous ammonia in which impurities with low volatility are reduced can be derived.

  In the present embodiment, the vaporizer 2 vaporizes the liquid crude ammonia derived from the raw material storage tank 1 at a vaporization rate of 90 to 95% by volume and separates it into a gas phase component and a liquid phase component. In this case, 90 to 95% by volume of the liquid crude ammonia derived from the raw material storage tank 1 becomes a gas phase component, and 5 to 10% by volume becomes a liquid phase component.

  The vaporizer 2 is connected to a second pipe 82 provided with a second valve 821 and a discharge pipe 80A provided with a discharge valve 801A. The second pipe 82 is a pipe through which gaseous ammonia derived from the vaporizer 2 flows toward the adsorption unit 3, and is connected to the flow rate regulator 71. In the vaporizer 2, the low-volatile impurities separated and removed from the ammonia as a liquid phase component flow through the discharge pipe 80A and are discharged to the outside of the system with the discharge valve 801A being opened. In the vaporizer 2, gaseous ammonia obtained as a gas phase component flows through the second pipe 82 and is supplied to the flow rate regulator 71 with the second valve 821 opened.

  A third pipe 83 is connected to the flow regulator 71, and the end of the third pipe 83 opposite to the side connected to the flow regulator 71 is branched. One of the ends of the third pipe 83 branched is connected to a fourth pipe 84 connected to the tower top of the first adsorption tower 31 described later, and the other branched branch is a second adsorption tower described later. It is connected to the 5th piping 85 connected to 32 tower tops.

  The fourth pipe 84 is provided with a fourth valve 841 that opens or closes the flow path in the fourth pipe 84. The fifth pipe 85 is provided with a fifth valve 851 that opens or closes the flow path in the fifth pipe 85. The gaseous ammonia whose flow rate is adjusted by the flow rate regulator 71 flows through the third pipe 83 and the fourth pipe 84 in a state where the fourth valve 841 is opened and the fifth valve 851 is closed. It is supplied to the adsorption tower 31. The gaseous ammonia whose flow rate has been adjusted by the flow rate regulator 71 flows through the third pipe 83 and the fifth pipe 85 with the fifth valve 851 opened and the fourth valve 841 closed. It is supplied to the second adsorption tower 32. That is, the first adsorption tower 31 and the second adsorption tower 32 are connected in parallel via the fourth pipe 84 and the fifth pipe 85.

  The adsorption unit 3 adsorbs and removes impurities contained in gaseous ammonia derived from the vaporizer 2 for purification. The adsorption unit 3 includes a first adsorption tower 31 and a second adsorption tower 32 which are adsorption units.

  The first adsorption tower 31 is, in order from the tower top to the tower bottom (from the upstream side to the downstream side in the ammonia flow direction), the tower top adsorption layer 311, the first intermediate adsorption layer 312, and the second intermediate adsorption layer. 313 and a tower bottom adsorbing layer 314 are stacked.

  The tower top adsorption layer 311 is a layer containing a first adsorbent and has a function as a first adsorbent layer. The first adsorbent is a porous adsorbent having a high adsorbability for water. Examples of such a first adsorbent include activated carbon, MS-13X (porous synthetic zeolite having a pore size of 9 mm), activated alumina, and the like. In the present embodiment, activated carbon is used as the first adsorbent.

  The first intermediate adsorption layer 312 is a layer containing a second adsorbent and has a function as a second adsorbent layer. The second adsorbent is a porous adsorbent having a high adsorbability for organic compounds having less than 5 carbon atoms (hydrocarbon, alcohol, ether, etc.). Examples of such second adsorbent include MS-3A (porous synthetic zeolite having a pore diameter of 3 mm), MS-4A (porous synthetic zeolite having a pore diameter of 4 mm), and MS-5A (porous having a pore diameter of 5 mm). Synthetic zeolite), hydrophilic zeolite such as MS-13X (porous synthetic zeolite having a pore size of 9 mm), hydrophobic zeolite such as high silica type (high silica / alumina ratio) zeolite, silica gel and the like. Similarly to the first intermediate adsorption layer 312, the second intermediate adsorption layer 313 is a layer containing a second adsorbent and has a function as a second adsorbent layer. However, although the first intermediate adsorption layer 312 and the second intermediate adsorption layer 313 are the same because they are layers containing the second adsorbent, different types of adsorbents are used.

  The tower bottom adsorption layer 314 is a layer containing a third adsorbent and has a function as a third adsorbent layer. The third adsorbent is a porous adsorbent having high adsorbability for organic compounds having 5 or more carbon atoms (such as hydrocarbons) and water. Examples of such a third adsorbent include activated carbon and MS-13X.

  The laminated structure in the first adsorption tower 31 will be described with a specific example. In the first specific example, the tower top adsorption layer 311 is a layer containing activated carbon (GG, manufactured by Kuraray Chemical Co., Ltd.) as the first adsorbent, and the first intermediate adsorption layer 312 is hydrophilic as the second adsorbent. It is a layer containing zeolite (MS-3A, manufactured by Tosoh Corporation), and the second intermediate adsorption layer 313 is a layer containing silica gel (Sylbeed N, manufactured by Mizusawa Chemical Co., Ltd.) as the second adsorbent, The adsorption layer 314 is a layer containing activated carbon (GG, manufactured by Kuraray Chemical Co., Ltd.) as a third adsorbent.

  In the second specific example, the tower top adsorption layer 311 is a layer containing activated carbon (GG, manufactured by Kuraray Chemical Co., Ltd.) as the first adsorbent, and the first intermediate adsorption layer 312 is hydrophilic as the second adsorbent. It is a layer containing zeolite (MS-3A, manufactured by Tosoh Corporation), and the second intermediate adsorption layer 313 is a layer containing silica gel (Sylbeed N, manufactured by Mizusawa Chemical Co., Ltd.) as the second adsorbent, The adsorption layer 314 is a layer containing MS-13X (SA-600A, manufactured by Tosoh Corporation) as a third adsorbent.

  In the third specific example, the tower top adsorption layer 311 is a layer containing activated carbon (GG, manufactured by Kuraray Chemical Co., Ltd.) as the first adsorbent, and the first intermediate adsorption layer 312 is hydrophilic as the second adsorbent. It is a layer containing zeolite (MS-4A, manufactured by Tosoh Corporation), and the second intermediate adsorption layer 313 is a hydrophobic zeolite (HSZ-300, silica / alumina ratio = 10, manufactured by Tosoh Corporation) as the second adsorbent. The tower bottom adsorption layer 314 is a layer containing MS-13X (SA-600A, manufactured by Tosoh Corporation) as the third adsorbent.

  In the fourth specific example, the tower top adsorption layer 311 is a layer containing activated carbon (GG, manufactured by Kuraray Chemical Co., Ltd.) as the first adsorbent, and the first intermediate adsorption layer 312 is hydrophilic as the second adsorbent. It is a layer containing zeolite (MS-4A, manufactured by Tosoh Corporation), and the second intermediate adsorption layer 313 is a hydrophobic zeolite (HSZ-300, silica / alumina ratio = 10, manufactured by Tosoh Corporation) as the second adsorbent. The tower bottom adsorption layer 314 is a layer containing a laminate of MS-13X (SA-600A, manufactured by Tosoh Corporation) and activated carbon (GG, manufactured by Kuraray Chemical Co., Ltd.) as a third adsorbent. is there.

  The second adsorption tower 32 has a tower top adsorption layer 321, a first intermediate adsorption layer 322, and a second intermediate adsorption layer in order from the tower top to the tower bottom (from the upstream to the downstream in the ammonia flow direction). 323 and a tower bottom adsorption layer 324 are laminated.

  The tower top adsorption layer 321 is a layer including the first adsorbent, which is configured in the same manner as the tower top adsorption layer 311 of the first adsorption tower 31 described above, and has a function as a first adsorbent layer. The 1st intermediate adsorption layer 322 is a layer containing the 2nd adsorbent comprised similarly to the 1st intermediate adsorption layer 312 of the 1st adsorption tower 31 mentioned above, and has a function as the 2nd adsorbent layer. The second intermediate adsorption layer 323 is a layer including the second adsorbent, which is configured in the same manner as the second intermediate adsorption layer 313 of the first adsorption tower 31 described above, and has a function as a second adsorbent layer. The tower bottom adsorption layer 324 is a layer including a third adsorbent, which is configured in the same manner as the tower bottom adsorption layer 314 of the first adsorption tower 31 described above, and has a function as a third adsorbent layer.

  The first adsorbent, the second adsorbent, and the third adsorbent used in the first adsorption tower 31 and the second adsorption tower 32 are adsorbed impurities (processed by heating, depressurization, heating, and depressurization). Organic compounds such as moisture and hydrocarbons) can be desorbed and regenerated. For example, when desorbing impurities adsorbed on the adsorbent by heat treatment, heating may be performed at a temperature of 200 to 350 ° C.

  Moreover, in the ammonia purification system 100 of this embodiment, the temperature of the first adsorption tower 31 and the second adsorption tower 32 is controlled to 0 to 60 ° C., and the pressure is controlled to 0.1 to 1.0 MPa. If the temperature of the first adsorption tower 31 and the second adsorption tower 32 is less than 0 ° C., cooling to remove the heat of adsorption generated during the adsorption removal of impurities may be required, which may reduce the energy efficiency. When the temperature of the 1st adsorption tower 31 and the 2nd adsorption tower 32 exceeds 60 degreeC, there exists a possibility that the adsorption capacity of the impurity by adsorbent may fall. Moreover, when the pressure of the 1st adsorption tower 31 and the 2nd adsorption tower 32 is less than 0.1 Mpa, there exists a possibility that the adsorption capability of the impurity by adsorption agent may fall, and when a pressure exceeds 1.0 Mpa, A large amount of energy is required to maintain a constant pressure, which may reduce energy efficiency.

  Moreover, it is preferable that the linear velocity (linear velocity) in the 1st adsorption tower 31 and the 2nd adsorption tower 32 is 0.1-10.0 m / sec. When the linear velocity is less than 0.1 m / sec, it is not preferable because it takes a long time to remove impurities, and when the linear velocity exceeds 10.0 m / sec, the heat of adsorption generated during the adsorption removal of impurities. In this case, the adsorption capacity of the impurities by the adsorbent may be lowered. The linear velocity is calculated by converting the amount of gaseous ammonia supplied to the first adsorption tower 31 or the second adsorption tower 32 per unit time into the gas volume of NTP and emptying the adsorption towers 31 and 32. It is the value obtained by dividing by the tower cross section.

  In the ammonia purification system 100 of the present embodiment, it is preferable to analyze the concentration of impurities contained in the ammonia derived from the first adsorption tower 31 and the second adsorption tower 32. As a device for analyzing the concentration of impurities contained in ammonia, a gas chromatograph analyzer (GC-PDD: pulse discharge detector) can be exemplified. Specific examples of the gas chromatograph analyzer include GC-4000 manufactured by GL Sciences, Inc. Based on the analysis result by the gas chromatograph analyzer, a partial reduction condition (such as setting of the condensation rate) in the capacitor 4 described later may be set.

  A sixth pipe 86 is connected to the bottom of the first adsorption tower 31, and the sixth pipe 86 is branched at the end opposite to the side connected to the first adsorption tower 31. Yes. One of the ends of the sixth pipe 86 branched is connected to a seventh pipe 87 connected to the capacitor 4 described later, and the other branched is connected to the top of the second adsorption tower 32. It is connected to the eighth pipe 88.

  The seventh pipe 87 is provided with a seventh valve 871 that opens or closes the flow path in the seventh pipe 87. The eighth pipe 88 is provided with an eighth valve 881 that opens or closes the flow path in the eighth pipe 88. The gaseous ammonia from which impurities have been adsorbed and removed by the first adsorption tower 31 flows through the sixth pipe 86 and the seventh pipe 87 with the seventh valve 871 opened and the eighth valve 881 closed. It is supplied to the capacitor 4. The gaseous ammonia from which impurities have been adsorbed and removed by the first adsorption tower 31 passes through the sixth pipe 86 and the eighth pipe 88 with the eighth valve 881 opened and the seventh valve 871 closed. The flow is supplied to the second adsorption tower 32. That is, the first adsorption tower 31 and the second adsorption tower 32 are connected in series via the sixth pipe 86 and the eighth pipe 88.

  Further, a ninth pipe 89 is connected to the bottom of the second adsorption tower 32, and the end of the ninth pipe 89 opposite to the side connected to the second adsorption tower 32 is The capacitor 4 is connected. The ninth pipe 89 is provided with a ninth valve 891 that opens or closes the flow path in the ninth pipe 89. A tenth pipe 90 branched from the ninth pipe 89 is connected to the ninth pipe 89 downstream of the ninth valve 891 in the ammonia flow direction. The tenth pipe 90 is provided with a tenth valve 901 that opens or closes the flow path in the tenth pipe 90. Further, the end of the tenth pipe 90 opposite to the side connected to the ninth pipe 89 is connected to the top of the first adsorption tower 31.

  The gaseous ammonia from which impurities have been adsorbed and removed by the second adsorption tower 32 flows through the ninth pipe 89 and is supplied to the capacitor 4 with the ninth valve 891 opened and the tenth valve 901 closed. The The gaseous ammonia from which impurities have been adsorbed and removed by the second adsorption tower 32 passes through the ninth pipe 89 and the tenth pipe 90 with the ninth valve 891 opened and the tenth valve 901 opened. The flow is supplied to the first adsorption tower 31.

  In the adsorption unit 3 configured as described above, the connection between the first adsorption tower 31 and the second adsorption tower 32 can be changed in four patterns.

  In the first connection pattern, the fourth valve 841 and the seventh valve 871 are opened, and the fifth valve 851, the eighth valve 881, the ninth valve 891, and the tenth valve 901 are closed. In the first connection pattern, gaseous ammonia that is derived from the vaporizer 2 and whose flow rate is adjusted by the flow rate regulator 71 flows through the fourth pipe 84 and is supplied to the first adsorption tower 31. Then, the purified gaseous ammonia derived from the first adsorption tower 31 flows through the sixth pipe 86 and the seventh pipe 87 and is supplied to the capacitor 4. In such a first connection pattern, gaseous ammonia derived from the vaporizer 2 is purified only by the first adsorption tower 31. During the adsorption removal by the first adsorption tower 31, the used second adsorption tower 32 can be regenerated so that the adsorption removal operation can be performed again by the used second adsorption tower 32.

  In the second connection pattern, the fifth valve 851 and the ninth valve 891 are opened, and the fourth valve 841, the seventh valve 871, the eighth valve 881, and the tenth valve 901 are closed. In this second connection pattern, gaseous ammonia derived from the vaporizer 2 and whose flow rate is adjusted by the flow rate regulator 71 flows through the fifth pipe 85 and is supplied to the second adsorption tower 32. The purified gaseous ammonia derived from the second adsorption tower 32 flows through the ninth pipe 89 and is supplied to the capacitor 4. In such a second connection pattern, gaseous ammonia derived from the vaporizer 2 is purified only by the second adsorption tower 32. During the adsorption removal by the second adsorption tower 32, the used first adsorption tower 31 can be regenerated so that the adsorption removal operation can be performed again by the used first adsorption tower 31.

  In the third connection pattern, the fourth valve 841, the eighth valve 881, and the ninth valve 891 are opened, and the fifth valve 851, the seventh valve 871, and the tenth valve 901 are closed. In the third connection pattern, gaseous ammonia that is derived from the vaporizer 2 and whose flow rate is adjusted by the flow rate regulator 71 flows through the fourth pipe 84 and is supplied to the first adsorption tower 31. The purified gaseous ammonia derived from the first adsorption tower 31 flows through the sixth pipe 86 and the eighth pipe 88 and is supplied to the second adsorption tower 3. The purified gaseous ammonia derived from the second adsorption tower 32 flows through the ninth pipe 89 and is supplied to the capacitor 4. In such a third connection pattern, gaseous ammonia derived from the vaporizer 2 is purified by the first adsorption tower 31 and the second adsorption tower 32. Impurities contained in gaseous ammonia derived from the vaporizer 2 can be adsorbed and removed by the first adsorbing tower 31 and the second adsorbing tower 32 connected in series, so that the ability to adsorb and remove impurities can be improved. Can do.

  In the fourth connection pattern, the fourth valve 841, the eighth valve 881, the ninth valve 891, and the tenth valve 901 are opened, and the fifth valve 851 and the seventh valve 871 are closed. In the fourth connection pattern, gaseous ammonia that is derived from the vaporizer 2 and whose flow rate is adjusted by the flow rate regulator 71 flows through the fourth pipe 84 and is supplied to the first adsorption tower 31. The purified gaseous ammonia derived from the first adsorption tower 31 flows through the sixth pipe 86 and the eighth pipe 88 and is supplied to the second adsorption tower 32. The purified gaseous ammonia derived from the second adsorption tower 32 flows through the ninth pipe 89 and the tenth pipe 90 and is supplied again to the first adsorption tower 31, and the first adsorption tower 31 and the second adsorption tower are supplied. The adsorption removal operation by 32 is repeated. When the opened tenth valve 901 is closed, gaseous ammonia derived from the second adsorption tower 32 flows through the ninth pipe 89 and is supplied to the condenser 4. In such a fourth connection pattern, gaseous ammonia derived from the vaporizer 2 can be repeatedly purified by the first adsorption tower 31 and the second adsorption tower 32.

  Gaseous ammonia derived from the first adsorption tower 31 or the second adsorption tower 32 is supplied to the condenser 4. Capacitor 4 degenerates gaseous ammonia derived from first adsorption tower 31 or second adsorption tower 32 and separates it into a gas phase component and a liquid phase component, whereby hydrogen contained in ammonia, Highly volatile impurities such as nitrogen, oxygen, argon, carbon monoxide and carbon dioxide are separated and removed as a gas phase component to obtain liquid ammonia purified as a liquid phase component.

  Examples of the condenser 4 include a multitubular condenser and a plate heat exchanger. In this embodiment, a multitubular condenser is used as the condenser 4. The condenser 4 condenses 70 to 99% by volume of gaseous ammonia derived from the first adsorption tower 31 or the second adsorption tower 32 and separates it into a gas phase component and a liquid phase component. In this case, 1 to 30% by volume, which is a part of gaseous ammonia derived from the first adsorption tower 31 or the second adsorption tower 32, is condensed so as to become a gas phase component, It separates into a liquid phase component. Thus, highly volatile impurities contained in the gaseous ammonia after adsorption removal can be separated and removed as a gas phase component, and liquid ammonia purified as a liquid phase component can be obtained with high yield.

  Further, the condensation condition in the condenser 4 is not limited as long as a part of the gaseous ammonia led out from the first adsorption tower 31 or the second adsorption tower 32 becomes a liquid. The pressure and time may be set as appropriate. In the present embodiment, the capacitor 4 condenses gaseous ammonia derived from the first adsorption tower 31 or the second adsorption tower 32 at a temperature of −77 to 40 ° C. It is preferable that it is comprised so that it may isolate | separate. As a result, it is possible to obtain a purified liquid ammonia by efficiently condensing gaseous ammonia derived from the first adsorption tower 31 or the second adsorption tower 32, and to reduce the purity of the liquid ammonia. Can be increased. When the temperature at the time of condensation with respect to gaseous ammonia in the condenser 4 is less than −77 ° C., it is not preferable because it requires a lot of energy for cooling. Since the concentration of impurities contained in the liquid ammonia obtained by condensation increases, it is not preferable.

  The capacitor 4 also condenses gaseous ammonia derived from the first adsorption tower 31 or the second adsorption tower 32 under a pressure of 0.007 to 2.0 MPa into a gas phase component and a liquid phase component. It is preferably configured to separate. When the pressure at the time of condensation with respect to gaseous ammonia in the condenser 4 is less than 0.007 MPa, the temperature for condensing ammonia is lowered, so that a lot of energy is required for cooling, which is not preferable. If it exceeds 0.0 MPa, the temperature at which ammonia is condensed becomes high, which is not preferable because the concentration of impurities contained in liquid ammonia obtained by condensing a part of ammonia is high.

  In the ammonia purification system 100 of the present embodiment, the condenser 4 condenses part of the gaseous ammonia derived from the first adsorption tower 31 or the second adsorption tower 32 and separates it into a gas phase component and a liquid phase component. Therefore, highly volatile impurities can be separated and removed as a gas phase component, and liquid ammonia purified as a liquid phase component can be obtained. Therefore, ammonia can be purified with a simplified system without providing distillation means as in the prior art.

  When the impurities contained in the crude ammonia are separated and removed by precision distillation, since distillation is performed while refluxing, liquid ammonia is heated and evaporated in a distillation column to form gaseous ammonia. The operation of condensing gaseous ammonia from the rectifying column with the condenser at the top of the column to form liquid ammonia is repeated. Therefore, large energy is input to the rectification operation.

  On the other hand, when the impurities contained in the ammonia are separated and removed by the partial condensation in the condenser 4, the gaseous ammonia is only condensed once, so that less energy is required. Thus, compared with the purification method of ammonia by rectification, the purification method by partial condensation in the condenser 4 not only provides high-purity ammonia in a short time but also has a great energy advantage. Recognize.

  The liquid ammonia obtained as a liquid phase component by the partial condensation in the capacitor 4 is quickly derived from the capacitor 4, and the operation of the capacitor 4 is performed so that only the uncondensed gas phase component exists in the capacitor 4. Is necessary to obtain high-purity ammonia.

  The capacitor 4 is connected to an eleventh pipe 91 provided with an eleventh valve 911 and a twelfth pipe 92 provided with a twelfth valve 921. The eleventh pipe 91 is connected between the capacitor 4 and the recovery tank 5.

  In the capacitor 4, highly volatile impurities separated and removed from ammonia as a gas phase component are discharged out of the system through the twelfth pipe 92 with the twelfth valve 921 opened. In the capacitor 4, the liquid ammonia obtained as the liquid phase component is supplied to the recovery tank 5 through the eleventh pipe 91 with the eleventh valve 911 being opened.

  The recovery tank 5 stores liquid ammonia obtained as a liquid phase component by the condenser 4. Connected to the recovery tank 5 is a thirteenth pipe 93 communicating with the recovery tank 5 and the outside and serving as a flow path for discharging the gas phase component to the outside. The thirteenth pipe 93 is provided with a thirteenth valve 931 that opens or closes the flow path in the thirteenth pipe 93. In the ammonia purification system 100 of the present embodiment, by opening the thirteenth valve 931 while the eleventh valve 911 is closed, highly volatile impurities are removed from the liquid ammonia stored in the recovery tank 5. A discharge operation for discharging and removing can be performed. By performing the discharge operation in the recovery tank 5, the purity of the liquid ammonia stored in the recovery tank 5 can be further increased.

  Moreover, the temperature and pressure of the recovery tank 5 are controlled under constant conditions so that ammonia can be stored in a liquid state. A cooling liquid feeder 72 is connected to the recovery tank 5 and the condenser 4 via a fourteenth pipe 94. The fourteenth pipe 94 flows with the coolant sent from the coolant feeding device 72, and the recovery tank 5 and the condenser 4 are maintained at a predetermined temperature by the cooling capacity of the coolant.

  A filling device 6 is connected to the recovery tank 5 via a fifteenth pipe 95 provided with a fifteenth valve 951. The liquid ammonia stored in the recovery tank 5 flows through the fifteenth pipe 95 and is supplied to the filling device 6 when the fifteenth valve 951 is opened. The ammonia thus supplied to the filling device 6 is filled into a product filling container or the like by the filling device 6.

  In the ammonia purification system 100 of the present embodiment configured as described above, the adsorbent layers having different adsorbing capabilities for water, an organic compound having less than 5 carbon atoms, and an organic compound having 5 or more carbon atoms are stacked. Since the adsorption tower 31 and the second adsorption tower 32 adsorb and remove impurities contained in the crude ammonia, impurities (mainly water and organic compounds) contained in the crude ammonia can be efficiently adsorbed and removed. And since the capacitor | condenser 4 carries out partial condensation of the ammonia derived | led-out from the 1st adsorption tower 31 or the 2nd adsorption tower 32, and isolate | separates into a gaseous-phase component and a liquid phase component, hydrogen, nitrogen, oxygen, argon, monoxide Highly volatile impurities such as carbon and carbon dioxide can be separated and removed as a gas phase component to obtain liquid ammonia purified as a liquid phase component. Therefore, in the ammonia purification system 100 of the present embodiment, ammonia can be purified by a simplified method without performing distillation with reflux as in the prior art, and energy consumption is suppressed and ammonia is reduced. It can be purified efficiently.

  Further, the first adsorption tower 31 and the second adsorption tower 32 of the adsorption unit 3 are arranged such that the tower top adsorption layers 311 and 321 containing the first adsorbent, the second adsorption, from the upstream side to the downstream side in the flow direction of the crude ammonia. The first intermediate adsorption layers 312, 322 containing the adsorbent, the second intermediate adsorption layers 313, 323 containing the second adsorbent, and the tower bottom adsorption layers 314, 324 containing the third adsorbent are laminated in this order. . Since the tower top adsorbing layers 311 and 321 contain the first adsorbent having high adsorbing ability for water, the crude ammonia flowing through the first adsorbing tower 31 and the second adsorbing tower 32 is first put into the tower top. Most of water is adsorbed and removed in the adsorption layers 311 and 321. As a result, in the first intermediate adsorption layers 312, 322, the second intermediate adsorption layers 313, 323, and the tower bottom adsorption layers 314, 324 disposed downstream of the tower top adsorption layers 311, 321 in the ammonia flow direction. Adsorption ability with respect to the organic compound is sufficiently exhibited, and the adsorption / removability of impurities from the crude ammonia by the first adsorption tower 31 and the second adsorption tower 32 can be improved.

  In the present embodiment, as described above, the first adsorption tower 31 and the second adsorption tower 32 include adsorbent layers having different adsorption capacities for water, an organic compound having less than 5 carbon atoms, and an organic compound having 5 or more carbon atoms. It has a laminated structure. Similar to the first adsorption tower 31 and the second adsorption tower 32 configured as described above, a tower-top adsorption layer containing a first adsorbent is used as the construction of the adsorption tower that exhibits the ability to adsorb and remove impurities contained in ammonia. And an adsorbing tower having a mixed layer in which the second adsorbent and the third adsorbent are mixed, which is disposed downstream of the tower top adsorbing layer in the flow direction of the crude ammonia.

  In such an adsorption tower having a tower top adsorption layer and a mixed layer, if the second adsorbent and the third adsorbent constituting the mixed layer are packed in a state of being uniformly dispersed in the layer, There is no need to stack and fill each adsorbent.

  Moreover, as the structure which exhibits the adsorption removal ability with respect to the impurity contained in ammonia similarly to the 1st adsorption tower 31 and the 2nd adsorption tower 32, a 1st adsorbent, a 2nd adsorbent, and a 3rd adsorbent, A configuration in which a plurality of adsorption towers individually packed is connected in series is also conceivable. Even this method has no effect on the adsorption and removal of impurities. In a configuration in which a plurality of adsorption towers are connected in series, if the plurality of adsorption towers are arranged in series in the horizontal direction, there is a problem that the installation area is widened. No points will occur. When a plurality of adsorption towers are connected in series, the construction method of the adsorption towers may be selected in consideration of equipment costs such as the size of the adsorption towers, an increase in the number of towers, and the length of the connecting pipes.

  FIG. 2 is a diagram showing a configuration of an ammonia purification system 150 according to the second embodiment of the present invention. The ammonia purification system 150 of the present embodiment is similar to the ammonia purification system 100 described above, and corresponding portions are denoted by the same reference numerals and description thereof is omitted. The ammonia purification system 150 is the same as the ammonia purification system 100 except that the configuration of the adsorption unit 151 is different from the configuration of the adsorption unit 3 described above.

  The adsorption unit 151 performs purification by adsorbing and removing impurities contained in gaseous ammonia led out from the vaporizer 2. In the present embodiment, the adsorption unit 151 includes a first adsorption tower 1511, a second adsorption tower 1512, and a third adsorption tower 1513.

  The first adsorption tower 1511, the second adsorption tower 1512, and the third adsorption tower 1513 are configured in the same manner as the first adsorption tower 31 described above. Specifically, the first adsorption tower 1511 has a tower top adsorption layer 15111, a first intermediate adsorption layer 15112, in order from the tower top to the tower bottom (from the upstream to the downstream in the ammonia flow direction). A second intermediate adsorption layer 15113 and a tower bottom adsorption layer 15114 are laminated.

  The tower top adsorption layer 15111 is a layer containing a first adsorbent and has a function as a first adsorbent layer. The first adsorbent is a porous adsorbent having a high adsorbability for water. Examples of the first adsorbent include activated carbon.

  The first intermediate adsorption layer 15112 is a layer containing a second adsorbent and has a function as a second adsorbent layer. The second adsorbent is a porous adsorbent having a high adsorbability for organic compounds having less than 5 carbon atoms (hydrocarbon, alcohol, ether, etc.). Examples of such second adsorbent include MS-3A (porous synthetic zeolite having a pore diameter of 3 mm), MS-4A (porous synthetic zeolite having a pore diameter of 4 mm), and MS-5A (porous having a pore diameter of 5 mm). Synthetic zeolite), hydrophilic zeolite such as MS-13X (porous synthetic zeolite having a pore size of 9 mm), hydrophobic zeolite such as high silica type (high silica / alumina ratio) zeolite, silica gel and the like. Similarly to the first intermediate adsorption layer 15112, the second intermediate adsorption layer 15113 is a layer containing a second adsorbent and has a function as a second adsorbent layer. However, although the first intermediate adsorption layer 15112 and the second intermediate adsorption layer 15113 are the same because they are layers containing the second adsorbent, different types of adsorbents are used.

  The tower bottom adsorption layer 15114 is a layer containing a third adsorbent and has a function as a third adsorbent layer. The third adsorbent is a porous adsorbent having high adsorbability for organic compounds having 5 or more carbon atoms (such as hydrocarbons) and water. Examples of such a third adsorbent include activated carbon and MS-13X.

  The second adsorption tower 1512 has a tower top adsorption layer 15121, a first intermediate adsorption layer 15122, and a second intermediate adsorption layer in order from the tower top to the tower bottom (from the upstream to the downstream in the ammonia flow direction). 15123 and a tower bottom adsorbing layer 15124 are stacked.

  The tower top adsorption layer 15121 is a layer containing the first adsorbent, which is configured in the same manner as the tower top adsorption layer 311 of the first adsorption tower 31 described above, and has a function as a first adsorbent layer. The first intermediate adsorption layer 15122 is a layer including the second adsorbent, which is configured in the same manner as the first intermediate adsorption layer 312 of the first adsorption tower 31 described above, and has a function as a second adsorbent layer. The second intermediate adsorption layer 15123 is a layer including the second adsorbent, which is configured in the same manner as the second intermediate adsorption layer 313 of the first adsorption tower 31 described above, and has a function as a second adsorbent layer. The tower bottom adsorption layer 15124 is a layer containing a third adsorbent, which is configured in the same manner as the tower bottom adsorption layer 314 of the first adsorption tower 31 described above, and has a function as a third adsorbent layer.

  In the present embodiment, the 15A piping 152, the 15B piping 153, and the 15C piping 154 branched from the third piping 83 are connected to the third piping 83 through which gaseous ammonia derived from the vaporizer 2 flows. .

  The 15A pipe 152 branches from the third pipe 83 and is connected to the top of the first adsorption tower 1511. The 15A pipe 152 is provided with a 15A valve 1521 that opens or closes the flow path in the 15A pipe 152. The 15B pipe 153 branches from the third pipe 83 and is connected to the tower top of the second adsorption tower 1512. The 15B pipe 153 is provided with a 15B valve 1531 that opens or closes the flow path in the 15B pipe 153. The 15th C pipe 154 branches from the third pipe 83 and is connected to the top of the third adsorption tower 1513. The 15th C pipe 154 is provided with a 15th C valve 1541 that opens or closes the flow path in the 15th C pipe 154.

  A 15D pipe 155 through which gaseous ammonia derived from the first adsorption tower 1511 flows is connected to the bottom of the first adsorption tower 1511. The 15D pipe 155 is provided with a 15D valve 1551 that opens or closes the flow path in the 15D pipe 155. A 15E pipe 156 through which gaseous ammonia derived from the second adsorption tower 1512 flows is connected to the bottom of the second adsorption tower 1512. The 15E pipe 156 is provided with a 15E valve 1561 that opens or closes the flow path in the 15E pipe 156. A 15th F pipe 157 through which gaseous ammonia derived from the third adsorption tower 1513 flows is connected to the bottom of the third adsorption tower 1513. The 15th F pipe 157 is provided with a 15th F valve 1571 for opening or closing the flow path in the 15th F pipe 157.

  In addition, a 15th G pipe 158 branched from the 15D pipe 155 is connected to the 15D pipe 155. The 15G pipe 158 is branched from the 15D pipe 155 and connected to the 15B pipe 153, and a flow path for introducing gaseous ammonia led out from the first adsorption tower 1511 into the second adsorption tower 1512. It becomes. The 15G pipe 158 is provided with a 15G valve 1581 that opens or closes the flow path in the 15G pipe 158. A 15th H pipe 159 branched from the 15th G pipe 158 is connected to the 15th G pipe 158. The 25th H pipe 159 is branched from the 15th G pipe 158 and connected to the 15th C pipe 154, and a flow path for introducing gaseous ammonia derived from the first adsorption tower 1511 to the third adsorption tower 1513. It becomes. The 15th H pipe 159 is provided with a 15th H valve 1591 that opens or closes the flow path in the 15th H pipe 159.

  In addition, a 15I pipe 160 and a 15J pipe 161 branched from the 15E pipe 156 are connected to the 15E pipe 156. The 15I pipe 160 branches from the 15E pipe 156 and is connected to the 15A pipe 152, and a flow path for introducing gaseous ammonia led out from the second adsorption tower 1512 into the first adsorption tower 1511. Become. The 15I pipe 160 is provided with a 15I valve 1601 that opens or closes the flow path in the 15I pipe 160. The 15J pipe 161 is branched from the 15E pipe 156 and connected to the 15C pipe 154, and a flow path for introducing gaseous ammonia led out from the second adsorption tower 1512 into the third adsorption tower 1513, Become. The 15J pipe 161 is provided with a 15J valve 1611 that opens or closes the flow path in the 15J pipe 161.

  Further, the 15th F pipe 157 is connected to a 15K pipe 162 branched from the 15th F pipe 157. This 15K pipe 162 is branched from the 15th F pipe 157 and connected to the 15A pipe 152, and a flow path for introducing gaseous ammonia derived from the third adsorption tower 1513 into the first adsorption tower 1511. It becomes. The 15th K pipe 162 is provided with a 15th K valve 1621 that opens or closes the flow path in the 15th K pipe 162. A 15th L pipe 163 branched from the 15th K pipe 162 is connected to the 15th K pipe 162. This 15L pipe 163 is branched from the 15K pipe 162 and connected to the 15B pipe 153, and a flow path for introducing gaseous ammonia derived from the third adsorption tower 1513 into the second adsorption tower 1512. It becomes. The 15th L pipe 163 is provided with a 15th L valve 1631 that opens or closes the flow path in the 15th L pipe 163.

  Further, in the 15D pipe 155, the 15E pipe 156 and the 15F pipe 157, the 15M pipe 164 is connected to the downstream end portion in the flow direction of gaseous ammonia. The 15M pipe 164 is supplied with gaseous ammonia derived from any one of the first adsorption tower 1511, the second adsorption tower 1512 and the third adsorption tower 1513. The 15th M pipe 164 is provided with a 15th N pipe 165 branched from the 15th M pipe 164 and connected to the capacitor 4.

  In the ammonia purification system 150 configured as described above, there are the following six connection patterns for connecting the first adsorption tower 1511, the second adsorption tower 1512, and the third adsorption tower 1513.

  The first connection pattern is a connection pattern that allows gaseous ammonia derived from the vaporizer 2 to pass through the first adsorption tower 1511 and the second adsorption tower 1512 in this order. In the first connection pattern, the 15A valve 1521, the 15E valve 1561 and the 15G valve 1581 are opened, the 15B valve 1531, the 15C valve 1541, the 15D valve 1551, the 15F valve 1571, the 15H valve 1591, The 15I valve 1601, the 15J valve 1611, the 15K valve 1621 and the 15L valve 1631 are closed.

  As a result, gaseous ammonia derived from the vaporizer 2 flows through the 15A piping 152 and is introduced into the first adsorption tower 1511, and gaseous ammonia derived from the first adsorption tower 1511 is converted into the 15D piping. 155 and the 15G pipe 158 are passed through the second adsorption tower 1512 and gaseous ammonia derived from the second adsorption tower 1512 flows through the 15E pipe 156 and is supplied to the 15M pipe 164. Then, gaseous ammonia is introduced into the condenser 4 from the 15th M pipe 164.

  In such a first connection pattern, impurities contained in gaseous ammonia can be adsorbed and removed by the first adsorption tower 1511 and the second adsorption tower 1512, so that the ability to adsorb and remove impurities can be improved. it can. In the first connection pattern, since the adsorption removal operation in the third adsorption tower 1513 is not executed, the third adsorption tower 1513 can be regenerated.

  The second connection pattern is a connection pattern that allows gaseous ammonia derived from the vaporizer 2 to pass through the first adsorption tower 1511 and the third adsorption tower 1513 in this order. In the second connection pattern, the 15A valve 1521, the 15F valve 1571 and the 15H valve 1591 are opened, the 15B valve 1531, the 15C valve 1541, the 15D valve 1551, the 15E valve 1561, the 15G valve 1581, The 15I valve 1601, the 15J valve 1611, the 15K valve 1621 and the 15L valve 1631 are closed.

  As a result, gaseous ammonia derived from the vaporizer 2 flows through the 15A piping 152 and is introduced into the first adsorption tower 1511, and gaseous ammonia derived from the first adsorption tower 1511 is converted into the 15D piping. 155, the 15G pipe 158 and the 15H pipe 159, are introduced into the third adsorption tower 1513, and the gaseous ammonia led out from the third adsorption tower 1513 flows through the 15th F pipe 157 and the 15M pipe. 164 is supplied, and gaseous ammonia is introduced into the condenser 4 from the 15th M pipe 164.

  In such a second connection pattern, impurities contained in gaseous ammonia can be adsorbed and removed by the first adsorption tower 1511 and the third adsorption tower 1513, so that the ability to adsorb and remove impurities can be improved. it can. In the second connection pattern, since the adsorption removal operation in the second adsorption tower 1512 is not executed, the second adsorption tower 1512 can be regenerated.

  The third connection pattern is a connection pattern that allows gaseous ammonia derived from the vaporizer 2 to pass through the second adsorption tower 1512 and the first adsorption tower 1511 in this order. In the third connection pattern, the 15B valve 1531, the 15D valve 1551, and the 15I valve 1601 are opened, the 15A valve 1521, the 15C valve 1541, the 15E valve 1561, the 15F valve 1571, the 15G valve 1581, The 15th H valve 1591, the 15th J valve 1611, the 15th K valve 1621 and the 15th L valve 1631 are closed.

  Thereby, the gaseous ammonia derived from the vaporizer 2 flows through the 15B pipe 153 and is introduced into the second adsorption tower 1512, and the gaseous ammonia derived from the second adsorption tower 1512 is converted into the 15E pipe. 156 and the 15I piping 160 are introduced into the first adsorption tower 1511 and the gaseous ammonia led out from the first adsorption tower 1511 flows through the 15D piping 155 and is supplied to the 15M piping 164. Gaseous ammonia is introduced into the condenser 4 from the 15M pipe 164.

  In such a third connection pattern, impurities contained in gaseous ammonia can be adsorbed and removed by the first adsorption tower 1511 and the second adsorption tower 1512, so that the ability to adsorb and remove impurities can be improved. it can. In the third connection pattern, since the adsorption removal operation in the third adsorption tower 1513 is not executed, the third adsorption tower 1513 can be regenerated.

  The fourth connection pattern is a connection pattern that allows gaseous ammonia derived from the vaporizer 2 to pass through the second adsorption tower 1512 and the third adsorption tower 1513 in this order. In the fourth connection pattern, the 15B valve 1531, the 15F valve 1571, and the 15J valve 1611 are opened, the 15A valve 1521, the 15C valve 1541, the 15D valve 1551, the 15E valve 1561, the 15G valve 1581, The 15H valve 1591, the 15I valve 1601, the 15K valve 1621 and the 15L valve 1631 are closed.

  Thereby, the gaseous ammonia derived from the vaporizer 2 flows through the 15B pipe 153 and is introduced into the second adsorption tower 1512, and the gaseous ammonia derived from the second adsorption tower 1512 is converted into the 15E pipe. 156 and the 15J pipe 161 are passed through and introduced into the third adsorption tower 1513, and the gaseous ammonia led out from the third adsorption tower 1513 flows through the 15th F pipe 157 and is supplied to the 15M pipe 164. Gaseous ammonia is introduced into the condenser 4 from the 15th M pipe 164.

  In such a fourth connection pattern, impurities contained in gaseous ammonia can be adsorbed and removed by the second adsorption tower 1512 and the third adsorption tower 1513, so that the ability to adsorb and remove impurities can be improved. it can. In the fourth connection pattern, since the adsorption removal operation in the first adsorption tower 1511 is not executed, the first adsorption tower 1511 can be regenerated.

  The fifth connection pattern is a connection pattern that allows gaseous ammonia derived from the vaporizer 2 to pass through the third adsorption tower 1513 and the first adsorption tower 1511 in this order. In the fifth connection pattern, the 15C valve 1541, the 15D valve 1551, and the 15K valve 1621 are opened, the 15A valve 1521, the 15B valve 1531, the 15E valve 1561, the 15F valve 1571, the 15G valve 1581, The 15th H valve 1591, the 15th I valve 1601, the 15th J valve 1611 and the 15th L valve 1631 are closed.

  Thereby, the gaseous ammonia derived from the vaporizer 2 flows through the 15C pipe 154 and is introduced into the third adsorption tower 1513, and the gaseous ammonia derived from the third adsorption tower 1513 is converted into the 15th F pipe. 157 and the 15K pipe 162 are introduced into the first adsorption tower 1511 and gaseous ammonia derived from the first adsorption tower 1511 flows through the 15D pipe 155 and is supplied to the 15M pipe 164. Gaseous ammonia is introduced into the condenser 4 from the 15th M pipe 164.

  In such a fifth connection pattern, impurities contained in gaseous ammonia can be adsorbed and removed by the first adsorption tower 1511 and the third adsorption tower 1513, so that the ability to adsorb and remove impurities can be improved. it can. In the fifth connection pattern, since the adsorption removal operation in the second adsorption tower 1512 is not executed, the second adsorption tower 1512 can be regenerated.

  The sixth connection pattern is a connection pattern that allows gaseous ammonia derived from the vaporizer 2 to pass through the third adsorption tower 1513 and the second adsorption tower 1512 in this order. In the sixth connection pattern, the 15C valve 1541, the 15E valve 1561 and the 15L valve 1631 are opened, and the 15A valve 1521, the 15B valve 1531, the 15D valve 1551, the 15F valve 1571, the 15G valve 1581, The 15th H valve 1591, the 15th I valve 1601, the 15th J valve 1611 and the 15th K valve 1621 are closed.

  Thereby, the gaseous ammonia derived from the vaporizer 2 flows through the 15C pipe 154 and is introduced into the third adsorption tower 1513, and the gaseous ammonia derived from the third adsorption tower 1513 is converted into the 15th F pipe. 157, the 15K pipe 162 and the 15L pipe 163 flow into the second adsorption tower 1512 and the gaseous ammonia led out from the second adsorption tower 1512 flows through the 15E pipe 156 and the 15M pipe. 164 is supplied, and gaseous ammonia is introduced into the condenser 4 from the 15th M pipe 164.

  In such a sixth connection pattern, impurities contained in gaseous ammonia can be adsorbed and removed by the second adsorption tower 1512 and the third adsorption tower 1513, so that the ability to adsorb and remove impurities can be improved. it can. Note that, in the sixth connection pattern, the adsorption removal operation in the first adsorption tower 1511 is not executed, so that the first adsorption tower 1511 can be regenerated.

  FIG. 3 is a diagram showing a configuration of an ammonia purification system 200 according to the third embodiment of the present invention. The ammonia purification system 200 of the present embodiment is similar to the ammonia purification system 100 described above, and corresponding portions are denoted by the same reference numerals and description thereof is omitted. The ammonia purification system 200 is the same as the ammonia purification system 100 except that the configuration of the adsorption unit 201 is different from the configuration of the adsorption unit 3 described above.

  The adsorption unit 201 adsorbs and removes impurities contained in gaseous ammonia derived from the vaporizer 2 for purification. In the present embodiment, the adsorption unit 201 includes a first adsorption tower 2011, a second adsorption tower 2012, a third adsorption tower 2013, and a fourth adsorption tower 2014.

  The first adsorption tower 2011 and the third adsorption tower 2013 are connected to the 20th pipe 202 in parallel. The twentieth pipe 202 is provided with a twenty-first valve 2021 and a twenty-second valve 2022 that open or close the flow path in the twentieth pipe 202. In the twentieth piping 202, the 21st valve 2021 is disposed on the upstream side of the first adsorption tower 2011 (that is, the tower top side of the first adsorption tower 2011), and the 22nd valve 2022 is located upstream of the third adsorption tower 2013. It arrange | positions at the side (namely, tower top side of the 3rd adsorption tower 2013). When supplying gaseous ammonia derived from the vaporizer 2 to the first adsorption tower 2011, the 21st valve 2021 is opened, the 22nd valve 2022 is closed, and the vaporizer 2 is directed to the first adsorption tower 2011. Then, gaseous ammonia flows in the 20th pipe 202. In addition, when supplying gaseous ammonia derived from the vaporizer 2 to the third adsorption tower 2013, the 22nd valve 2022 is opened, the 21st valve 2021 is closed, and the third adsorption tower 2013 from the vaporizer 2 is closed. Gaseous ammonia flows in the 20th pipe 202 toward.

  As described above, the adsorption unit 201 includes the first adsorption tower 2011 and the third adsorption tower 2013 connected in parallel, so that the gaseous ammonia derived from the vaporizer 2 can be connected in parallel to the first adsorption tower. 2011 and the third adsorption tower 2013 can be introduced in a state of being distinguished from each other, for example, while the first adsorption tower 2011 is adsorbing and removing, the used third adsorption tower 2013 is again adsorbed. The used third adsorption tower 2013 can be regenerated so that the removal operation can be performed.

  The second adsorption tower 2012 is connected in series with the first adsorption tower 2011 via the 21st pipe 203. That is, in the 21st pipe 203, one end is connected to the tower bottom of the first adsorption tower 2011 and the other end is connected to the tower top of the second adsorption tower 2012. Thereby, gaseous ammonia led out from the vaporizer 2 and introduced into the first adsorption tower 2011 flows into the second adsorption tower 2012 through the 21st pipe 203 with the 23rd valve 2031 opened. be introduced. As described above, the adsorption unit 201 includes the first adsorption tower 2011 and the second adsorption tower 2012 connected in series, so that impurities contained in the gaseous ammonia derived from the vaporizer 2 can be removed from the first adsorption tower. Since it can be adsorbed and removed by 2011 and the second adsorption tower 2012, the ability to adsorb and remove impurities can be improved.

  Gaseous ammonia derived from the second adsorption tower 2012 flows through the 22nd pipe 204 and is supplied to the capacitor 4 with the 24th valve 2041 opened.

  The fourth adsorption tower 2014 is connected in series with the third adsorption tower 2013 via the 23rd pipe 205. That is, in the 23rd pipe 205, one end is connected to the tower bottom of the third adsorption tower 2013 and the other end is connected to the tower top of the fourth adsorption tower 2014. As a result, the gaseous ammonia led out from the vaporizer 2 and introduced into the third adsorption tower 2013 flows through the 23rd pipe 205 with the 25th valve 2051 opened to the fourth adsorption tower 2014. be introduced. Thus, the adsorption unit 201 has the third adsorption tower 2013 and the fourth adsorption tower 2014 connected in series, so that impurities contained in the gaseous ammonia derived from the vaporizer 2 can be removed from the third adsorption tower. Since it can be adsorbed and removed by 2013 and the fourth adsorption tower 2014, the ability to adsorb and remove impurities can be improved.

  The gaseous ammonia led out from the fourth adsorption tower 2014 flows through the 24th pipe 206 with the 26th valve 2061 being opened, and is supplied to the capacitor 4.

  The first adsorption tower 2011 in the adsorption unit 201 of the ammonia purification system 200 is arranged in order from the tower top to the tower bottom (from the upstream to the downstream in the ammonia flow direction). The adsorbing layer 20112, the second intermediate adsorbing layer 20113, the third intermediate adsorbing layer 20114, and the tower bottom adsorbing layer 20115 are stacked.

  The tower top adsorption layer 20111 is a layer containing the first adsorbent, which is configured in the same manner as the tower top adsorption layer 311 of the first adsorption tower 31 in the adsorption unit 3 described above, and has a function as the first adsorbent layer. Have. The 1st intermediate adsorption layer 20112 is a layer containing the 2nd adsorbent comprised similarly to the 1st intermediate adsorption layer 312 of the 1st adsorption tower 31 mentioned above, and has a function as a 2nd adsorbent layer. The second intermediate adsorption layer 20113 is a layer including the second adsorbent, which is configured in the same manner as the second intermediate adsorption layer 313 of the first adsorption tower 31 described above, and has a function as a second adsorbent layer. The third intermediate adsorption layer 20104 is a layer including the second adsorbent, which is configured in the same manner as the first intermediate adsorption layer 312 and the second intermediate adsorption layer 313 of the first adsorption tower 31 described above. It functions as a layer. However, the first intermediate adsorption layer 20112, the second intermediate adsorption layer 20113, and the third intermediate adsorption layer 20114 are the same because they are layers containing the second adsorbent, but different types of adsorbents are used. Use. The tower bottom adsorption layer 20115 is a layer containing the third adsorbent, which is configured in the same manner as the tower bottom adsorption layer 314 of the first adsorption tower 31 described above, and has a function as a third adsorbent layer.

  The laminated structure in the first adsorption tower 2011 will be described with a specific example. In the first specific example, the tower top adsorption layer 20111 is a layer containing activated carbon (GG, manufactured by Kuraray Chemical Co., Ltd.) as the first adsorbent, and the first intermediate adsorption layer 20112 is silica gel ( The second intermediate adsorption layer 20113 is a layer containing hydrophilic zeolite (MS-3A, manufactured by Tosoh Corporation) as the second adsorbent, and the third intermediate adsorption layer 20113. The intermediate adsorption layer 20114 is a layer containing hydrophobic zeolite (HSZ-300, silica / alumina ratio = 10, manufactured by Tosoh Corporation) as the second adsorbent, and the tower bottom adsorption layer 20115 is activated carbon as the third adsorbent. It is a layer containing (GG, manufactured by Kuraray Chemical Co., Ltd.).

  In the second specific example, the tower top adsorption layer 20111 is a layer containing activated carbon (GG, manufactured by Kuraray Chemical Co., Ltd.) as the first adsorbent, and the first intermediate adsorption layer 20112 is hydrophilic as the second adsorbent. It is a layer containing zeolite (MS-3A, manufactured by Tosoh Corporation), and the second intermediate adsorption layer 20113 is a layer containing silica gel (Sylbeed N, manufactured by Mizusawa Chemical Co., Ltd.) as the second adsorbent. The intermediate adsorption layer 20114 is a layer containing hydrophobic zeolite (HiSiv, manufactured by Union Showa Co., Ltd.) as the second adsorbent, and the tower bottom adsorption layer 20115 is MS-13X (produced by Tosoh Corporation) as the third adsorbent. It is a layer containing.

  In the ammonia purification system 200 of the present embodiment configured as described above, the adsorbent layers having different adsorption capacities for water, organic compounds having less than 5 carbon atoms, and organic compounds having 5 or more carbon atoms are stacked. Since the adsorption tower 2011, the second adsorption tower 2012, the third adsorption tower 2013, and the fourth adsorption tower 2014 adsorb and remove impurities contained in the crude ammonia, impurities contained in the crude ammonia (mainly water and organic Compound) can be efficiently adsorbed and removed. And since the capacitor | condenser 4 fractionates and isolate | separates the ammonia derived | led-out from the 2nd adsorption tower 2012 or the 4th adsorption tower 2014 into a gaseous-phase component and a liquid phase component, it is hydrogen, nitrogen, oxygen, argon, monoxide Highly volatile impurities such as carbon and carbon dioxide can be separated and removed as a gas phase component to obtain liquid ammonia purified as a liquid phase component. Therefore, in the ammonia purification system 200 of the present embodiment, ammonia can be purified by a simplified method without performing distillation with reflux as in the prior art, and energy consumption is suppressed and ammonia is reduced. It can be purified efficiently.

  FIG. 4 is a diagram showing a configuration of an ammonia purification system 300 according to the fourth embodiment of the present invention. The ammonia purification system 300 of the present embodiment is similar to the ammonia purification system 100 described above, and corresponding portions are denoted by the same reference numerals and description thereof is omitted. The ammonia purification system 300 is the same as the ammonia purification system 100 except that the configuration of the raw material storage tank 1A is different from the configuration of the raw material storage tank 1 described above.

  The raw material storage tank 1A provided in the ammonia purification system 300 stores crude ammonia as liquid ammonia and is controlled so as to have a predetermined temperature and pressure. The raw material storage tank 1A has a cylindrical internal space, and in the state where liquid crude ammonia is stored in the internal space, a gas phase is formed in the upper part of the raw material storage tank 1A, and a liquid phase is formed in the lower part. Is formed.

  In the present embodiment, the raw material storage tank 1 </ b> A derives the stored crude ammonia toward the adsorption unit 3. The ammonia purification system 300 is not provided with the above-described vaporizer 2. When crude ammonia is derived from the raw material storage tank 1A to the adsorption unit 3, most of low-volatile impurities (for example, moisture, hydrocarbons having more than 6 carbon atoms, etc.) are left in the liquid phase, and raw material storage is performed. It is derived as gaseous crude ammonia from the gas phase formed in the tank 1A. In the raw material storage tank 1A, a heating device 302 that heats the liquid crude ammonia in order to vaporize part of the liquid crude ammonia stored in the raw material storage tank 1A and increase the ammonia concentration in the gas phase. Is provided.

  A gaseous ammonia outlet pipe 301 is connected to the upper part of the raw material storage tank 1A (the part where the gas phase is formed). The end of the gaseous ammonia outlet pipe 301 opposite to the side connected to the raw material storage tank 1 </ b> A is connected to the flow rate regulator 71. The gaseous ammonia outlet pipe 301 is provided with an opening / closing valve 3011 that opens or closes the flow path in the gaseous ammonia outlet pipe 301.

  The crude ammonia stored in the raw material storage tank 1A is derived as gaseous crude ammonia from the gas phase formed in the raw material storage tank 1A with the opening / closing valve 3011 being opened. The gaseous crude ammonia derived from the raw material storage tank 1 </ b> A in this way flows through the gaseous ammonia outlet piping 301 and is supplied to the flow rate regulator 71. The gaseous crude ammonia is supplied to the adsorption unit 3 having the first adsorption tower 31 and the second adsorption tower 32 with the flow rate adjusted by the flow regulator 71. The gaseous crude ammonia supplied to the adsorption unit 3 is purified by removing impurities by the first adsorption tower 31 and the second adsorption tower 32. Further, gaseous ammonia purified in the first adsorption tower 31 and the second adsorption tower 32 is fractionated in the condenser 4 to separate and remove highly volatile impurities.

  In the ammonia purification system 300 of the present embodiment configured as described above, the adsorbent layers having different adsorption capacities for water, organic compounds having less than 5 carbon atoms, and organic compounds having 5 or more carbon atoms are stacked. Since the adsorption tower 31 and the second adsorption tower 32 adsorb and remove impurities contained in the crude gaseous ammonia, it is possible to efficiently remove the impurities (mainly water and organic compounds) contained in the crude ammonia. it can. And since the capacitor | condenser 4 carries out partial condensation of the ammonia derived | led-out from the 1st adsorption tower 31 or the 2nd adsorption tower 32, and isolate | separates into a gaseous-phase component and a liquid phase component, hydrogen, nitrogen, oxygen, argon, monoxide Highly volatile impurities such as carbon and carbon dioxide can be separated and removed as a gas phase component to obtain liquid ammonia purified as a liquid phase component. Therefore, in the ammonia purification system 300 of the present embodiment, ammonia can be purified by a simplified method without performing distillation with reflux as in the prior art, and energy consumption is suppressed and ammonia is reduced. It can be purified efficiently.

  FIG. 5 is a diagram showing a configuration of an ammonia purification system 400 according to the fifth embodiment of the present invention. The ammonia purification system 400 of the present embodiment is similar to the ammonia purification system 100 described above, and corresponding portions are denoted by the same reference numerals and description thereof is omitted. The ammonia purification system 400 is the same as the ammonia purification system 100 except that the configuration of the raw material storage tank 1B is different from the configuration of the raw material storage tank 1 described above.

  The raw material storage tank 1B provided in the ammonia purification system 400 stores crude ammonia as liquid ammonia and is controlled so as to have a predetermined temperature and pressure. The raw material storage tank 1B has a cylindrical internal space, and in the state where liquid crude ammonia is stored in the internal space, a gas phase is formed in the upper part of the raw material storage tank 1B, and a liquid phase is formed in the lower part. Is formed. The raw material storage tank 1B is heated to heat the liquid crude ammonia in order to vaporize part of the liquid crude ammonia stored in the raw material storage tank 1B and increase the ammonia concentration in the gas phase. A device 403 is provided.

  In the present embodiment, the raw material storage tank 1B is configured to be able to derive the stored crude ammonia from either the gas phase or the liquid phase.

  The concentration of gas phase impurities (particularly highly volatile impurities) formed in the raw material storage tank 1B varies depending on the amount of liquid crude ammonia charged (reserved amount) in the raw material storage tank 1B. The higher the filling amount of liquid crude ammonia in the raw material storage tank 1B, the higher the volatile impurity concentration in the gas phase formed in the raw material storage tank 1B. Further, the smaller the filling amount of the liquid crude ammonia in the raw material storage tank 1B, the lower the volatility of impurities (for example, water, organic compounds having a large number of carbon atoms) in the liquid phase formed in the raw material storage tank 1B. The concentration becomes high. That is, when liquid crude ammonia is derived from the liquid phase formed in the raw material storage tank 1B, the concentration of impurities with low volatility increases as the amount of liquid crude ammonia in the raw material storage tank 1B decreases. Crude ammonia is derived from the liquid phase of the raw material storage tank 1B.

  Therefore, the ammonia purification system 400 of the present embodiment derives crude ammonia from either the gas phase or the liquid phase according to the amount of liquid crude ammonia charged in the raw material storage tank 1B. The control of the derivation operation to be performed) is switched. The ammonia purification system 400 calculates a volume ratio that is a ratio of the volume of the liquid phase to the volume of the internal space in the raw material storage tank 1B, and when the volume ratio is equal to or greater than a predetermined threshold, It is configured to derive liquid crude ammonia from the liquid phase to be formed, and is configured to derive gaseous crude ammonia from the gas phase formed in the raw material storage tank 1B when it is less than the threshold. ing.

  Specifically, in the ammonia purification system 400, the liquid level height in the internal space of the liquid crude ammonia stored in the raw material storage tank 1B is detected. If the dimension of the size of the internal space is known in advance, the volume ratio can be calculated using the liquid level height. In particular, in an internal space having a constant cross-section parallel to the bottom surface, the ratio of the liquid level to the height of the internal space is the same as the volume ratio, so the volume ratio can be easily calculated.

  In this embodiment, since the internal space formed in the raw material storage tank 1B is a columnar shape, the cross section parallel to the circular bottom surface is a constant internal space. Therefore, the ratio of the liquid level to the height of the internal space is the same as the volume ratio. Therefore, the ammonia purification system 400 uses the value of the height of the internal space of the raw material storage tank 1B and the value of the liquid level, and the ratio of the liquid level to the height of the internal space ((the liquid level height / Height of the internal space), hereinafter referred to as “height ratio”) is calculated as a value corresponding to the volume ratio.

  Furthermore, in the ammonia purification system 400, when the height ratio is equal to or higher than a predetermined threshold value (threshold value = 1/2 in the present embodiment), liquid crude ammonia is formed from the liquid phase formed in the raw material storage tank 1B. So as to derive the crude ammonia in the raw material storage tank 1B. Further, in the ammonia purification system 400, when the height ratio is less than a predetermined threshold value, the raw material storage tank 1B is rough so that gaseous crude ammonia is derived from the gas phase formed in the raw material storage tank 1B. The ammonia deriving operation is controlled.

  In other words, the ammonia refining system 400 of the present embodiment is configured so that the liquid crude ammonia is in the raw material storage tank 1B up to a height position equal to or higher than ½ of the height of the raw material storage tank 1B (corresponding to the threshold value). When it is detected that the fuel is filled, liquid crude ammonia is derived from the liquid phase formed in the raw material storage tank 1B. In addition, the ammonia purification system 400 is filled with liquid crude ammonia up to a height position less than ½ of the height of the raw material storage tank 1B (corresponding to the threshold value) in the raw material storage tank 1B. Is detected, gaseous gaseous ammonia is derived from the gas phase formed in the raw material storage tank 1B.

  In this way, the crude ammonia can be stored in the raw material storage state with little variation in impurity concentration by switching the derivation state of the crude ammonia in accordance with the amount of liquid crude ammonia charged in the raw material storage tank 1B. It can be derived from the tank 1B. As a result, it is possible to prevent large variations in the purity of the finally purified ammonia.

  A liquid ammonia outlet pipe 401 is connected to the lower part (part where the liquid phase is formed) of the raw material storage tank 1B. The end of the liquid ammonia outlet pipe 401 opposite to the side connected to the raw material storage tank 1 </ b> B is connected to the vaporizer 2. The liquid ammonia outlet pipe 401 is provided with an opening / closing valve 4011 that opens or closes the flow path in the liquid ammonia outlet pipe 401. The crude ammonia stored in the raw material storage tank 1B is derived as liquid crude ammonia from the liquid phase formed in the raw material storage tank 1B with the open / close valve 4011 being opened. The liquid crude ammonia derived from the raw material storage tank 1B in this way flows through the liquid ammonia outlet piping 401 and is supplied to the vaporizer 2. The liquid crude ammonia derived from the raw material storage tank 1B is vaporized by the vaporizer 2 and supplied to the flow regulator 71 as gaseous ammonia. In this way, the gaseous ammonia vaporized by the vaporizer 2 is supplied to the adsorption unit 3 having the first adsorption tower 31 and the second adsorption tower 32 after the flow rate is adjusted by the flow rate regulator 71. Become.

  In addition, a gaseous ammonia outlet pipe 402 is connected to the upper part of the raw material storage tank 1B (the part where the gas phase is formed). The end of the gaseous ammonia outlet pipe 402 opposite to the side connected to the raw material storage tank 1 </ b> B is connected to the flow rate regulator 71. The gaseous ammonia lead-out pipe 402 is provided with an open / close valve 4021 that opens or closes the flow path in the gaseous ammonia lead-out pipe 402.

  The crude ammonia stored in the raw material storage tank 1B is derived as gaseous crude ammonia from the gas phase formed in the raw material storage tank 1B with the open / close valve 4021 being opened. The gaseous crude ammonia derived from the raw material storage tank 1B in this way flows through the gaseous ammonia outlet piping 402 and is supplied to the flow rate regulator 71. The gaseous crude ammonia is supplied to the adsorption unit 3 having the first adsorption tower 31 and the second adsorption tower 32 with the flow rate adjusted by the flow regulator 71.

  In the ammonia purification system 400 of the present embodiment, gaseous ammonia supplied to the adsorption unit 3 is purified by removing impurities by the first adsorption tower 31 and the second adsorption tower 32. Further, gaseous ammonia purified in the first adsorption tower 31 and the second adsorption tower 32 is fractionated in the condenser 4 to separate and remove highly volatile impurities.

  In the ammonia purification system 400 of the present embodiment configured as described above, the adsorbent layers having different adsorption capacities for water, organic compounds having less than 5 carbon atoms, and organic compounds having 5 or more carbon atoms are stacked. Since the adsorption tower 31 and the second adsorption tower 32 adsorb and remove impurities contained in the crude gaseous ammonia, it is possible to efficiently remove the impurities (mainly water and organic compounds) contained in the crude ammonia. it can. And since the capacitor | condenser 4 carries out partial condensation of the ammonia derived | led-out from the 1st adsorption tower 31 or the 2nd adsorption tower 32, and isolate | separates into a gaseous-phase component and a liquid phase component, hydrogen, nitrogen, oxygen, argon, monoxide Highly volatile impurities such as carbon and carbon dioxide can be separated and removed as a gas phase component to obtain liquid ammonia purified as a liquid phase component. Therefore, in the ammonia purification system 400 of the present embodiment, ammonia can be purified by a simplified method without performing distillation with reflux as in the prior art, and energy consumption is suppressed and ammonia is reduced. It can be purified efficiently.

1, 1A, 1B Raw material storage tank 2 Vaporizer 3, 151, 201 Adsorption unit 4 Capacitor 5 Recovery tank 6 Filling device 31, 1511, 2011 First adsorption tower 32, 1512, 2012 Second adsorption tower 100, 150, 200, 300,400 Ammonia purification system 1513, 2013 3rd adsorption tower 2014 4th adsorption tower 311, 321, 15111, 15121, 15131, 20111, 20121, 20131, 201141 Tower top adsorbing layer 312, 322, 15112, 15122, 15132, 20112 , 20122, 20132, 20142 1st intermediate adsorption layer 313,323,15113,15123,15133,2013,20123,20133,20143 2nd intermediate adsorption layer 314,324,15114,15124,1 5134, 2011, 20125, 20135, 20145 Column bottom adsorption layer 20134, 20124, 20134, 20144 Third intermediate adsorption layer

Claims (5)

In an ammonia purification system for purifying crude ammonia containing impurities,
Storage means for storing crude ammonia and deriving the stored crude ammonia;
Impurities contained in the crude ammonia derived from the storage means are purified by adsorbing and removing with an adsorbent selected from activated carbon, hydrophilic zeolite, hydrophobic zeolite, silica gel and activated alumina. A suction means for deriving,
A first adsorbent layer comprising a first adsorbent;
A plurality of second adsorbent layers including a second adsorbent of a type different from the first adsorbent;
A third adsorbent layer containing a third adsorbent of a type different from the second adsorbent, and an adsorbing means having one or a plurality of adsorbing portions laminated in the flow direction of the crude ammonia;
By separating the purified ammonia derived from the adsorption means into a gas phase component and a liquid phase component, the highly volatile impurities are separated and removed as a gas phase component and purified as a liquid phase component. An ammonia refining system comprising: a contraction means for obtaining the liquid ammonia. Vaporization means for evaporating a part of the liquid crude ammonia derived from the storage means and deriving gaseous ammonia;
The ammonia purification system according to claim 1, wherein the adsorption unit adsorbs and removes impurities contained in gaseous ammonia derived from the vaporization unit by the adsorption unit. The first adsorbent is an adsorbent having a high adsorbability for water,
The second adsorbent is an adsorbent having a high adsorbing ability for an organic compound having less than 5 carbon atoms,
3. The ammonia purification system according to claim 1, wherein the third adsorbent is an adsorbent having high adsorbability for an organic compound having 5 or more carbon atoms and water.   In the adsorbing portion, the first adsorbent layer, the plurality of second adsorbent layers, and the third adsorbent layer are laminated in this order from the upstream side to the downstream side in the flow direction of the crude ammonia. The ammonia purification system according to any one of claims 1 to 3. The adsorption means has a plurality of the adsorption portions,
The ammonia purification system according to any one of claims 1 to 4, wherein the plurality of adsorption units are connected in series or in parallel.

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