JP2014005157A - Ammonia purification system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ammonia purification system that can prevent the purity of ultimately purified ammonia from varying greatly.SOLUTION: In an ammonia purification system 100, a control unit 2 calculates a volume ratio of a liquid phase to the total volume of internal space in a raw material storage tank 1. Additionally, a control unit 2 controls the raw material storage tank 1 to deliver crude ammonia from the liquid phase when the volume ratio is a prescribed threshold or more. The control unit 2 controls the raw material storage tank 1 to deliver crude ammonia from a gas phase when the volume ratio is less than the threshold. Then, an adsorption unit 4 adsorbs and removes impurities contained in gaseous crude ammonia delivered from the gas phase in the raw material storage tank 1 or gaseous ammonia delivered from an evaporator 3 through adsorbents, and delivers the gaseous ammonia.

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. However, the technology for refining ammonia disclosed in Patent Documents 1 to 3 does not consider variations in impurity concentration during storage of crude ammonia.

  Crude ammonia is stored in a container such as a storage tank. The concentration of gas phase impurities (particularly highly volatile impurities) formed in the storage tank differs depending on the amount of liquid crude ammonia charged (storage amount) in the storage tank. The greater the amount of liquid crude ammonia charged in the storage tank, the higher the concentration of highly volatile impurities in the gas phase formed in the storage tank. Even when the crude ammonia derived from the storage tank is purified by an adsorption tower, distillation tower, etc. in such a state where the impurity concentration varies greatly, the purity of the finally purified ammonia varies greatly. End up.

  Accordingly, an object of the present invention is to provide an ammonia purification system that can prevent the occurrence of large variations in the purity of ammonia that is finally purified.

The present invention provides an ammonia purification system for purifying crude ammonia containing impurities.
Storage means for storing crude ammonia in the internal space so as to form a gas phase and a liquid phase, and deriving the stored crude ammonia from the gas phase or the liquid phase;
A volume ratio, which is a ratio of the volume of the liquid phase to the volume of the internal space in the storage means, is calculated. Controlling the storage means so that, when the volume ratio is less than the threshold, a derivation control means for controlling the storage means to derive crude ammonia from the gas phase;
Vaporizing means for evaporating a part of the liquid crude ammonia derived from the liquid phase of the storage means and deriving gaseous ammonia;
The gaseous crude ammonia derived from the vapor phase of the storage means or the impurities contained in the gaseous ammonia derived from the vaporization means are adsorbed and removed by an adsorbent to derive gaseous ammonia. And an adsorption means.

  Further, the ammonia purification system of the present invention separates and removes highly volatile impurities as gas phase components by decomposing ammonia derived from the adsorption means and separating it into a gas phase component and a liquid phase component, It is further characterized by further comprising a contraction means for obtaining liquid ammonia purified as a liquid phase component.

  The ammonia purification system of the present invention is further characterized by further comprising a distillation means for separating and removing impurities by distilling the ammonia derived from the adsorption means to obtain purified liquid ammonia.

  In the ammonia purification system of the present invention, the adsorption means is filled with at least three kinds of adsorbents selected from five kinds of adsorbents such as activated carbon, hydrophilic zeolite, hydrophobic zeolite, silica gel, and activated alumina. And having a plurality of adsorption regions.

  According to the present invention, the ammonia purification system is a system for purifying crude ammonia containing impurities, and includes a storage means, a derivation control means, a vaporization means, and an adsorption means. The storage means stores crude ammonia in the internal space so that a gas phase and a liquid phase are formed, and derives the stored crude ammonia from the gas phase or the liquid phase. The derivation control means controls the derivation operation of the crude ammonia in the storage means.

  The derivation control means calculates a volume ratio, which is a ratio of the volume of the liquid phase to the volume of the internal space in the storage means, and derives crude ammonia from the liquid phase when the volume ratio is equal to or greater than a predetermined threshold. The storage means is controlled to do so. The derivation control unit controls the storage unit so as to derive crude ammonia from the gas phase when the volume ratio is less than the threshold value. In other words, the derivation control means switches the derivation state of the crude ammonia in the storage means according to the filling amount (storage amount) of the liquid crude ammonia in the internal space of the storage means (either the gas phase or the liquid phase). (Control of the derivation operation for deriving crude ammonia from the control). Thereby, crude ammonia can be derived from the storage means in a state where there is little variation in impurity concentration. Therefore, it is possible to prevent a large variation in the purity of ammonia that is finally purified.

  In the ammonia purification system of the present invention, the vaporizing means vaporizes a part of the liquid crude ammonia derived from the liquid phase of the storage means to derive gaseous ammonia. As a result, low-volatile impurities (for example, moisture, hydrocarbons having 6 or more carbon atoms) contained in the crude ammonia remain in the liquid phase, and gaseous ammonia with reduced low-volatile impurities is derived. can do. The adsorbing means adsorbs and removes the impurities contained in the gaseous crude ammonia derived from the gas phase of the storage means or the gaseous ammonia derived from the vaporizing means by the adsorbent. Derives ammonia. By this adsorption means, impurities (mainly water and organic compounds) contained in the crude ammonia can be efficiently adsorbed and removed.

  According to the invention, the ammonia purification system further includes a partial reduction means. This partial contraction means separates and removes highly volatile impurities as a vapor phase component by separating the ammonia derived from the adsorption means into a vapor phase component and a liquid phase component, and as a liquid phase component. Purified liquid ammonia is obtained. As a result, highly volatile impurities such as hydrogen, nitrogen, oxygen, argon, carbon monoxide, and carbon dioxide can be separated and removed as gas phase components to obtain purified liquid ammonia as liquid phase components. it can. Therefore, in the ammonia purification system of the present invention, it is possible to purify ammonia by a simplified method without performing distillation accompanied by reflux, and it is possible to efficiently purify ammonia while suppressing energy consumption. it can.

  According to the invention, the ammonia purification system further includes distillation means. This distillation means can separate and remove impurities by distilling the ammonia derived from the adsorption means to obtain purified liquid ammonia.

  According to the invention, the adsorbing means includes a plurality of adsorbents each filled with at least three adsorbents selected from five adsorbents of activated carbon, hydrophilic zeolite, hydrophobic zeolite, silica gel, and activated alumina. It has an adsorption area. Thereby, the adsorption means can efficiently adsorb and remove impurities contained in gaseous crude ammonia derived from the gas phase of the storage means or gaseous ammonia derived from the vaporization means.

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 200 which concerns on 2nd Embodiment of this invention. It is a figure which shows the structure of the ammonia purification system 300 which concerns on 3rd 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 control unit 2 that is a derivation control means, a vaporizer 3 that is a vaporization means, an adsorption unit 4 that is an adsorption means, a capacitor 5 that is a partial reduction means, and a recovery A tank 61 is included.

  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 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 1 and increase the ammonia concentration in the gas phase. A device 11 is provided.

  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 70 serving as a flow path for discharging is connected. The exhaust pipe 70 is provided with an exhaust valve 701 that opens or closes a flow path in the exhaust pipe 70. The ammonia purification system 100 of 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 701. Yes. Specifically, after the liquid crude ammonia is stored in the raw material storage tank 1 for 0.5 to 3 days, the exhaust valve 701 is opened for 10 to 300 minutes. Thus, 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 70.

  Moreover, in this embodiment, the raw material storage tank 1 is comprised so that the stored crude ammonia can be derived | led-out from any phase of a gaseous phase and a liquid phase.

  A first pipe 71 serving as a pipe from which liquid crude ammonia is led is connected to the lower part of the raw material storage tank 1 (the part where the liquid phase is formed). The end of the first pipe 71 opposite to the side connected to the raw material storage tank 1 is connected to the vaporizer 3. The first pipe 71 is provided with a first valve 711 that opens or closes the flow path in the first pipe 71. The crude ammonia stored in the raw material storage tank 1 is derived as liquid crude ammonia from the liquid phase formed in the raw material storage tank 1 with the first valve 711 opened. The liquid crude ammonia derived from the raw material storage tank 1 in this way flows through the first pipe 71 and is supplied to the vaporizer 3. The liquid crude ammonia derived from the raw material storage tank 1 is vaporized by the vaporizer 3 and supplied to the flow regulator 63 as gaseous ammonia. The gaseous ammonia vaporized by the vaporizer 3 in this way is adjusted in flow rate by the flow rate regulator 63 and supplied to the adsorption unit 4.

  Further, a second pipe 72 serving as a pipe from which gaseous crude ammonia is led out is connected to the upper part of the raw material storage tank 1 (the part where the gas phase is formed). The end of the second pipe 72 opposite to the side connected to the raw material storage tank 1 is connected to the flow rate regulator 63. The second pipe 72 is provided with a second valve 721 that opens or closes the flow path in the second pipe 72.

  The crude ammonia stored in the raw material storage tank 1 is derived as gaseous crude ammonia from the gas phase formed in the raw material storage tank 1 with the second valve 721 opened. The gaseous crude ammonia led out from the raw material storage tank 1 in this way flows through the second pipe 72 and is supplied to the flow rate regulator 63. The gaseous crude ammonia is supplied to the adsorption unit 4 with the flow rate adjusted by the flow rate regulator 63.

  The control unit 2 controls the crude ammonia derivation operation in the raw material storage tank 1. The control unit 2 calculates a volume ratio, which is a ratio of the volume of the liquid phase to the volume of the internal space in the raw material storage tank 1, and is formed in the raw material storage tank 1 when the volume ratio is equal to or greater than a predetermined threshold. The crude ammonia derivation operation of the raw material storage tank 1 is controlled so as to derive liquid crude ammonia from the liquid phase. The control unit 2 also supplies the crude ammonia in the raw material storage tank 1 so as to derive the gaseous crude ammonia from the gas phase formed in the raw material storage tank 1 when the volume ratio is less than the predetermined threshold. Controls the derivation operation.

  In the present embodiment, the control unit 2 includes a detection unit 21 and a derivation switching control unit 22. The detection unit 21 is realized by a liquid level sensor, for example, and detects the liquid level height in the internal space of liquid crude ammonia stored in the raw material storage tank 1. 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 1 is cylindrical, the cross section parallel to the circular bottom 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. Accordingly, the derivation switching control unit 22 uses the value of the height of the internal space of the raw material storage tank 1 and the value of the liquid level detected by the detection unit 21 to set the liquid level to the height of the internal space. Ratio ((liquid level height / internal space height), hereinafter referred to as “height ratio”) is calculated as a value corresponding to the volume ratio.

  Further, the derivation switching control unit 22 determines that the liquid-like roughening is performed from the liquid phase formed in the raw material storage tank 1 when the height ratio is equal to or higher than a predetermined threshold value (threshold value = 1/2 in the present embodiment). The derivation operation of the crude ammonia in the raw material storage tank 1 is controlled so as to derive ammonia. Further, the derivation switching control unit 22 causes the raw material storage tank 1 to derive gaseous crude ammonia from the gas phase formed in the raw material storage tank 1 when the height ratio is less than the predetermined threshold value. The crude ammonia derivation operation is controlled.

  In other words, the ammonia purification system 100 of the present embodiment is configured so that the liquid crude ammonia is in the raw material storage tank 1 up to a height position equal to or higher than 1/2 the height of the raw material storage tank 1 (corresponding to the threshold value). When the detection unit 21 detects that it is filled, the derivation switching control unit 22 opens the first valve 711 and closes the second valve 721 so that the liquid phase formed in the raw material storage tank 1 Liquid crude ammonia is configured to flow out through the first pipe 71. Further, the ammonia purification system 100 is filled with liquid crude ammonia up to a height position less than ½ of the height of the raw material storage tank 1 (corresponding to the threshold value) in the raw material storage tank 1. Is detected by the detection unit 21, the derivation switching control unit 22 opens the second valve 721 and closes the first valve 711, so that gaseous crude ammonia is formed from the gas phase formed in the raw material storage tank 1. Is configured to flow out through the second pipe 72.

  The concentration of gas phase impurities (particularly highly volatile impurities) formed in the raw material storage tank 1 varies depending on the amount of liquid crude ammonia charged (reserved amount) in the raw material storage tank 1. As the amount of liquid crude ammonia charged in the raw material storage tank 1 increases, the concentration of highly volatile impurities in the gas phase formed in the raw material storage tank 1 increases. In addition, the smaller the filling amount of liquid crude ammonia in the raw material storage tank 1, 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 1. The concentration becomes high. That is, when liquid crude ammonia is derived from the liquid phase formed in the raw material storage tank 1, as the filling amount of the liquid crude ammonia in the raw material storage tank 1 decreases, the concentration of impurities with low volatility increases. Crude ammonia is derived from the liquid phase of the raw material storage tank 1.

  Therefore, as described above, the ammonia purification system 100 according to the present embodiment has a crude ammonia derivation state (either a gas phase or a liquid phase) according to the amount of liquid crude ammonia charged in the raw material storage tank 1. The control of the derivation operation for deriving crude ammonia from the control) is switched. As a result, crude ammonia can be derived from the raw material storage tank 1 with little variation in impurity concentration. Therefore, it is possible to prevent a large variation in the purity of ammonia that is finally purified.

  The vaporizer 3 vaporizes a part of the liquid crude ammonia derived from the liquid phase of the raw material storage tank 1. That is, the vaporizer 3 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 3 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 3 separates the liquid crude ammonia derived from the liquid phase of the raw material storage tank 1 into a vapor phase component and a liquid phase component by vaporizing at a vaporization rate of 90 to 95% by volume. To do. 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 3 is connected to a third pipe 73 provided with a third valve 731 and a fourth pipe 74 provided with a fourth valve 741. The third pipe 73 is a pipe through which gaseous ammonia derived from the vaporizer 3 flows toward the adsorption unit 4, and is connected to the flow rate regulator 63. In the vaporizer 3, the low-volatile impurities separated and removed from ammonia as a liquid phase component flow through the fourth pipe 74 and are discharged to the outside of the system with the fourth valve 741 opened. In the vaporizer 3, gaseous ammonia obtained as a gas phase component flows through the third pipe 73 and is supplied to the flow rate regulator 63 with the third valve 731 open.

  The flow rate regulator 63 serves as a flow path through which gaseous ammonia derived from the gas phase of the raw material storage tank 1 or gaseous ammonia derived from the vaporizer 3 flows toward the adsorption unit 4. Five pipes 75 are connected. A sixth pipe 76, a seventh pipe 77, and an eighth pipe 78 that branch from the fifth pipe 75 are connected to the fifth pipe 75.

  The sixth pipe 76 branches from the fifth pipe 75 and is connected to the tower top of the first adsorption tower 41 described later. The sixth pipe 76 is provided with a sixth valve 761 that opens or closes the flow path in the sixth pipe 76. The seventh pipe 77 branches from the fifth pipe 75 and is connected to the tower top of the second adsorption tower 42 described later. The seventh pipe 77 is provided with a seventh valve 771 that opens or closes the flow path in the seventh pipe 77. The eighth pipe 78 branches from the fifth pipe 75 and is connected to the tower top of the third adsorption tower 43 described later. The eighth pipe 78 is provided with an eighth valve 781 that opens or closes the flow path in the eighth pipe 78.

  The gaseous ammonia whose flow rate has been adjusted by the flow rate regulator 63 is the fifth pipe 75 and the sixth pipe with the sixth valve 761 opened and the seventh valve 771 and the eighth valve 781 closed. It flows through 76 and is supplied to the first adsorption tower 41. Further, the gaseous ammonia whose flow rate is adjusted by the flow rate regulator 63 is the same as that of the fifth pipe 75 and the seventh pipe 771 with the seventh valve 771 opened and the sixth valve 761 and the eighth valve 781 closed. It flows through the seven pipes 77 and is supplied to the second adsorption tower 42. Further, the gaseous ammonia whose flow rate is adjusted by the flow rate regulator 63, the fifth valve 751 and the eighth pipe 781 are opened in the state where the eighth valve 781 is opened and the sixth valve 761 and the seventh valve 771 are closed. It flows through the eight pipes 78 and is supplied to the third adsorption tower 43.

  The adsorption unit 4 adsorbs and removes gaseous ammonia derived from the gas phase of the raw material storage tank 1 or impurities contained in gaseous ammonia derived from the vaporizer 3 for purification. The adsorption unit 4 includes a first adsorption tower 41, a second adsorption tower 42, and a third adsorption tower 43, which are adsorption units.

  The first adsorption tower 41 may have any configuration as long as it is filled with an adsorbent capable of adsorbing and removing impurities contained in gaseous ammonia supplied via the flow rate regulator 63. . In the present embodiment, the first adsorption tower 41 is arranged in order from the tower top to the tower bottom (from the upstream to the downstream in the ammonia flow direction), the tower top adsorption area 411, the tower intermediate adsorption area 412, and It has a structure in which a tower bottom adsorption region 413 is provided.

  The column top adsorption region 411, the column intermediate adsorption region 412, and the column bottom adsorption region 413 are at least three adsorbents selected from five types of adsorbents of activated carbon, hydrophilic zeolite, hydrophobic zeolite, silica gel, and activated alumina. Are filled regions. Examples of hydrophilic zeolite 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), MS-5A (porous synthetic zeolite having a pore diameter of 5 mm), MS- 13X (porous synthetic zeolite having a pore size of 9 mm) and the like, and examples of the hydrophobic zeolite include high silica type (high silica / alumina ratio) zeolite.

  The tower top adsorption region 411 is an adsorption region mainly for adsorbing and removing water. One or more kinds of porous adsorbents selected from activated carbon, MS-13X, and activated alumina having high adsorption ability for water are contained. It is a filled adsorption area. The tower intermediate adsorption region 412 is mainly an adsorption region for adsorbing and removing organic compounds having less than 5 carbon atoms, and is selected from hydrophobic zeolite, hydrophilic zeolite, and silica gel having high adsorption ability for organic compounds having less than 5 carbon atoms. This is an adsorption region filled with one or more kinds of porous adsorbents. The tower bottom adsorption region 413 is an adsorption region mainly for adsorbing and removing organic compounds having 5 or more carbon atoms and water, and is selected from activated carbon and MS-13X having high adsorption ability for organic compounds having 5 or more carbon atoms and water. This is an adsorption region filled with one or more kinds of porous adsorbents.

  In the second adsorption tower 42, the tower top adsorption area 421, the tower intermediate adsorption area 422, and the tower bottom adsorption area 423 are sequentially arranged from the tower top to the tower bottom (from the upstream side to the downstream side in the ammonia flow direction). Is provided. In the second adsorption tower 42, the tower top adsorption region 421 is configured similarly to the tower top adsorption region 411 of the first adsorption tower 41, and the tower intermediate adsorption region 422 is similar to the tower intermediate adsorption region 412 of the first adsorption tower 41. The tower bottom adsorption region 423 is configured in the same manner as the tower bottom adsorption region 413 of the first adsorption tower 41.

  The third adsorption tower 43 has a tower top adsorption area 431, a tower intermediate adsorption area 432, and a tower bottom adsorption area 433 in order from the tower top to the tower bottom (from the upstream to the downstream in the ammonia flow direction). Is provided. In the third adsorption tower 43, the tower top adsorption area 431 is configured in the same manner as the tower top adsorption area 411 of the first adsorption tower 41, and the tower intermediate adsorption area 432 is similar to the tower intermediate adsorption area 412 of the first adsorption tower 41. The tower bottom adsorption region 433 is configured in the same manner as the tower bottom adsorption region 413 of the first adsorption tower 41.

  The adsorbent used in the first adsorption tower 41, the second adsorption tower 42, and the third adsorption tower 43 is formed by adsorbing impurities (organic substances such as moisture and hydrocarbons) by any one of heating, decompression, heating and decompression. Compound) can be removed 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.

  In the ammonia purification system 100 of the present embodiment, the first adsorption tower 41, the second adsorption tower 42, and the third adsorption tower 43 are controlled to a temperature of 0 to 60 ° C. and a pressure of 0.1 to 1.0 MPa. Controlled. When the temperature of the first adsorption tower 41, the second adsorption tower 42, and the third adsorption tower 43 is lower than 0 ° C., cooling is required to remove the adsorption heat generated during the adsorption removal of impurities, resulting in a decrease in energy efficiency. There is a risk. When the temperature of the 1st adsorption tower 41, the 2nd adsorption tower 42, and the 3rd adsorption tower 43 exceeds 60 degreeC, there exists a possibility that the adsorption capacity of the impurity by adsorption agent may fall. Moreover, when the pressure of the 1st adsorption tower 41, the 2nd adsorption tower 42, and the 3rd adsorption tower 43 is less than 0.1 Mpa, there exists a possibility that the adsorption capacity of the impurity by an adsorbent may fall, and a pressure is 1.0 Mpa. In the case of exceeding the above, a large amount of energy is required to maintain a constant pressure, which may reduce the energy efficiency.

  Moreover, it is preferable that the linear velocity (linear velocity) in the 1st adsorption tower 41, the 2nd adsorption tower 42, and the 3rd adsorption tower 43 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 41, the second adsorption tower 42, or the third adsorption tower 43 per unit time into the gas volume of NTP, It is a value obtained by dividing by the empty cross-sectional area of the tower.

  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 41, the second adsorption tower 42, and the third adsorption tower 43. 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 5 described later may be set.

  A ninth pipe 79 through which gaseous ammonia led out from the first adsorption tower 41 flows is connected to the bottom of the first adsorption tower 41. The ninth pipe 79 is provided with a ninth valve 791 that opens or closes the flow path in the ninth pipe 79. A tenth pipe 80 through which gaseous ammonia led out from the second adsorption tower 42 flows is connected to the bottom of the second adsorption tower 42. The tenth pipe 80 is provided with a tenth valve 801 that opens or closes the flow path in the tenth pipe 80. An eleventh pipe 81 through which gaseous ammonia derived from the third adsorption tower 43 flows is connected to the bottom of the third adsorption tower 43. The eleventh pipe 81 is provided with an eleventh valve 811 that opens or closes the flow path in the eleventh pipe 81.

  In addition, a twelfth pipe 82 branched from the ninth pipe 79 is connected to the ninth pipe 79. The twelfth pipe 82 is branched from the ninth pipe 79 and connected to the seventh pipe 77, and a flow path for introducing gaseous ammonia derived from the first adsorption tower 41 into the second adsorption tower 42. It becomes. The twelfth pipe 82 is provided with a twelfth valve 821 that opens or closes the flow path in the twelfth pipe 82. A thirteenth pipe 83 branched from the twelfth pipe 82 is connected to the twelfth pipe 82. The thirteenth pipe 83 is branched from the twelfth pipe 82 and connected to the eighth pipe 78, and a flow path for introducing gaseous ammonia led out from the first adsorption tower 41 into the third adsorption tower 43. It becomes. The thirteenth pipe 83 is provided with a thirteenth valve 831 that opens or closes the flow path in the thirteenth pipe 83.

  The tenth pipe 80 is connected to a fourteenth pipe 84 and a fifteenth pipe 85 branched from the tenth pipe 80. The fourteenth pipe 84 is branched from the tenth pipe 80 and connected to the sixth pipe 76, and a flow path for introducing gaseous ammonia derived from the second adsorption tower 42 into the first adsorption tower 41. Become. The fourteenth pipe 84 is provided with a fourteenth valve 841 that opens or closes the flow path in the fourteenth pipe 84. The fifteenth pipe 85 is branched from the tenth pipe 80 and connected to the eighth pipe 78, and a flow path for introducing gaseous ammonia derived from the second adsorption tower 42 into the third adsorption tower 43. Become. The fifteenth pipe 85 is provided with a fifteenth valve 851 that opens or closes the flow path in the fifteenth pipe 85.

  In addition, a sixteenth pipe 86 branched from the eleventh pipe 81 is connected to the eleventh pipe 81. The sixteenth pipe 86 is branched from the eleventh pipe 81 and connected to the sixth pipe 76, and a flow path for introducing gaseous ammonia led out from the third adsorption tower 43 into the first adsorption tower 41. It becomes. The sixteenth pipe 86 is provided with a sixteenth valve 861 that opens or closes the flow path in the sixteenth pipe 86. A seventeenth pipe 87 branched from the sixteenth pipe 86 is connected to the sixteenth pipe 86. The seventeenth pipe 87 is branched from the seventeenth pipe 87 and connected to the seventh pipe 77, and a flow path for introducing gaseous ammonia led out from the third adsorption tower 43 into the second adsorption tower 42. It becomes. The seventeenth pipe 87 is provided with a seventeenth valve 871 that opens or closes the flow path in the seventeenth pipe 87.

  In the ninth pipe 79, the tenth pipe 80, and the eleventh pipe 81, an eighteenth pipe 88 is connected to the downstream end portion in the flow direction of gaseous ammonia. The 18th pipe 88 is supplied with gaseous ammonia derived from any one of the first adsorption tower 41, the second adsorption tower 42 and the third adsorption tower 43. The eighteenth pipe 88 is provided with a nineteenth pipe 89 branched from the eighteenth pipe 88 and connected to the capacitor 5.

  In the ammonia purification system 100 configured as described above, there are the following six connection patterns for connecting the first adsorption tower 41, the second adsorption tower 42, and the third adsorption tower 43.

  The first connection pattern is a connection pattern that allows gaseous ammonia whose flow rate is adjusted by the flow rate regulator 63 to pass through the first adsorption tower 41 and the second adsorption tower 42 in this order. In the first connection pattern, the sixth valve 761, the tenth valve 801, and the twelfth valve 821 are opened, and the seventh valve 771, the eighth valve 781, the ninth valve 791, the eleventh valve 811, the thirteenth valve 831, The fourteenth valve 841, the fifteenth valve 851, the sixteenth valve 861, and the seventeenth valve 871 are closed.

  Thus, gaseous ammonia derived from the flow controller 63 flows through the sixth pipe 76 and is introduced into the first adsorption tower 41, and gaseous ammonia derived from the first adsorption tower 41 is the ninth The gaseous ammonia introduced from the second adsorption tower 42 after flowing through the pipe 79 and the twelfth pipe 82 flows through the tenth pipe 80 to the eighteenth pipe 88. Then, gaseous ammonia is introduced from the 18th pipe 88 into the condenser 5.

  In such a first connection pattern, impurities contained in gaseous ammonia can be adsorbed and removed by the first adsorption tower 41 and the second adsorption tower 42, 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 43 is not executed, the third adsorption tower 43 can be regenerated.

  The second connection pattern is a connection pattern that allows gaseous ammonia derived from the flow rate regulator 63 to pass through the first adsorption tower 41 and the third adsorption tower 43 in this order. In the second connection pattern, the sixth valve 761, the eleventh valve 811 and the thirteenth valve 831 are opened, and the seventh valve 771, the eighth valve 781, the ninth valve 791, the tenth valve 801, the twelfth valve 821, The fourteenth valve 841, the fifteenth valve 851, the sixteenth valve 861, and the seventeenth valve 871 are closed.

  Thus, gaseous ammonia derived from the flow controller 63 flows through the sixth pipe 76 and is introduced into the first adsorption tower 41, and gaseous ammonia derived from the first adsorption tower 41 is the ninth The gaseous ammonia introduced into the third adsorption tower 43 through the pipe 79, the twelfth pipe 82, and the thirteenth pipe 83 and flowing out from the third adsorption tower 43 flows through the eleventh pipe 81 and reaches the eighteenth. The gaseous ammonia is supplied to the pipe 88 and gaseous ammonia is introduced into the condenser 5 from the eighteenth pipe 88.

  In such a second connection pattern, impurities contained in gaseous ammonia can be adsorbed and removed by the first adsorption tower 41 and the third adsorption tower 43, so that the ability to adsorb and remove impurities can be improved. it can. In the second connection pattern, the adsorption removal operation in the second adsorption tower 42 is not executed, so that the second adsorption tower 42 can be regenerated.

  The third connection pattern is a connection pattern that allows gaseous ammonia derived from the flow rate regulator 63 to pass through the second adsorption tower 42 and the first adsorption tower 41 in this order. In the third connection pattern, the seventh valve 771, the ninth valve 791, and the fourteenth valve 841 are opened, and the sixth valve 761, the eighth valve 781, the tenth valve 801, the eleventh valve 811, the twelfth valve 821, The thirteenth valve 831, the fifteenth valve 851, the sixteenth valve 861, and the seventeenth valve 871 are closed.

  Thus, gaseous ammonia derived from the flow controller 63 flows through the seventh pipe 77 and is introduced into the second adsorption tower 42, and gaseous ammonia derived from the second adsorption tower 42 is The gaseous ammonia introduced into the first adsorption tower 41 through the pipe 80 and the fourteenth pipe 84 and led out from the first adsorption tower 41 flows through the ninth pipe 79 and is supplied to the eighteenth pipe 88. Gaseous ammonia is introduced into the condenser 5 from the eighteenth pipe 88.

  In such a third connection pattern, impurities contained in gaseous ammonia can be adsorbed and removed by the first adsorption tower 41 and the second adsorption tower 42, so that the ability to adsorb and remove impurities can be improved. it can. In the third connection pattern, the adsorption removal operation in the third adsorption tower 43 is not executed, so that the third adsorption tower 43 can be regenerated.

  The fourth connection pattern is a connection pattern that allows gaseous ammonia derived from the flow rate regulator 63 to pass through the second adsorption tower 42 and the third adsorption tower 43 in this order. In the fourth connection pattern, the seventh valve 771, the eleventh valve 811 and the fifteenth valve 851 are opened, and the sixth valve 761, the eighth valve 781, the ninth valve 791, the tenth valve 801, the twelfth valve 821, The thirteenth valve 831, the fourteenth valve 841, the sixteenth valve 861, and the seventeenth valve 871 are closed.

  Thus, gaseous ammonia derived from the flow controller 63 flows through the seventh pipe 77 and is introduced into the second adsorption tower 42, and gaseous ammonia derived from the second adsorption tower 42 is The gaseous ammonia introduced through the third adsorption tower 43 after flowing through the pipe 80 and the fifteenth pipe 85 flows through the eleventh pipe 81 and is supplied to the eighteenth pipe 88. The gaseous ammonia is introduced into the condenser 5 from the eighteenth pipe 88.

  In such a fourth connection pattern, impurities contained in gaseous ammonia can be adsorbed and removed by the second adsorption tower 42 and the third adsorption tower 43, 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 41 is not executed, the first adsorption tower 41 can be regenerated.

  The fifth connection pattern is a connection pattern that allows gaseous ammonia derived from the flow rate regulator 63 to pass through the third adsorption tower 43 and the first adsorption tower 41 in this order. In the fifth connection pattern, the eighth valve 781, the ninth valve 791, and the sixteenth valve 861 are opened, and the sixth valve 761, the seventh valve 771, the tenth valve 801, the eleventh valve 811, the twelfth valve 821, The thirteenth valve 831, the fourteenth valve 841, the fifteenth valve 851, and the seventeenth valve 871 are closed.

  Thereby, the gaseous ammonia derived from the flow controller 63 flows through the eighth pipe 78 and is introduced into the third adsorption tower 43, and the gaseous ammonia derived from the third adsorption tower 43 is the eleventh. The gaseous ammonia introduced into the first adsorption tower 41 through the pipe 81 and the sixteenth pipe 86 and led out from the first adsorption tower 41 flows through the ninth pipe 79 and is supplied to the eighteenth pipe 88. The gaseous ammonia is introduced into the condenser 5 from the eighteenth pipe 88.

  In such a fifth connection pattern, impurities contained in gaseous ammonia can be adsorbed and removed by the first adsorption tower 41 and the third adsorption tower 43, 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 42 is not executed, the second adsorption tower 42 can be regenerated.

  The sixth connection pattern is a connection pattern that allows gaseous ammonia derived from the flow rate regulator 63 to pass through the third adsorption tower 43 and the second adsorption tower 42 in this order. In the sixth connection pattern, the eighth valve 781, the tenth valve 801, and the seventeenth valve 871 are opened, and the sixth valve 761, the seventh valve 771, the ninth valve 791, the eleventh valve 811, the twelfth valve 821, The thirteenth valve 831, the fourteenth valve 841, the fifteenth valve 851, and the sixteenth valve 861 are closed.

  Thereby, the gaseous ammonia derived from the flow controller 63 flows through the eighth pipe 78 and is introduced into the third adsorption tower 43, and the gaseous ammonia derived from the third adsorption tower 43 is the eleventh. The gaseous ammonia introduced into the second adsorption tower 42 through the pipe 81, the sixteenth pipe 86, and the seventeenth pipe 87, and led out from the second adsorption tower 42 flows through the tenth pipe 80 and reaches the eighteenth. The gaseous ammonia is supplied to the pipe 88 and gaseous ammonia is introduced into the condenser 5 from the eighteenth pipe 88.

  In such a sixth connection pattern, impurities contained in gaseous ammonia can be adsorbed and removed by the second adsorption tower 42 and the third adsorption tower 43, 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 41 is not executed, so that the first adsorption tower 41 can be regenerated.

  Gaseous ammonia derived from the first adsorption tower 41, the second adsorption tower 42 or the third adsorption tower 43 is supplied to the capacitor 5. Capacitor 5 degenerates gaseous ammonia derived from first adsorption tower 41, second adsorption tower 42, or third adsorption tower 43 and separates it into a gas phase component and a liquid phase component, so that The highly volatile impurities such as hydrogen, nitrogen, oxygen, argon, carbon monoxide and carbon dioxide contained in are separated and removed as gas phase components to obtain liquid ammonia purified as a liquid phase component.

  Examples of the condenser 5 include a multi-tubular condenser and a plate heat exchanger. In this embodiment, a multi-tubular condenser is used as the condenser 5. The condenser 5 condenses 70 to 99% by volume of gaseous ammonia derived from the first adsorption tower 41, the second adsorption tower 42 or the third adsorption tower 43 and separates it into a gas phase component and a liquid phase component. . In this case, 1 to 30% by volume, which is part of gaseous ammonia derived from the first adsorption tower 41, the second adsorption tower 42, or the third adsorption tower 43, is condensed so as to become a gas phase component. Thus, the gas phase component and the liquid phase component are separated. 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 5 is limited as long as a part of the gaseous ammonia derived from the first adsorption tower 41, the second adsorption tower 42, or the third adsorption tower 43 becomes a liquid. What is necessary is just to set temperature, pressure, and time suitably. In this embodiment, the condenser 5 condenses gaseous ammonia derived from the first adsorption tower 41, the second adsorption tower 42, or the third adsorption tower 43 at a temperature of −77 to 40 ° C. It is preferably configured to separate into components and liquid phase components. As a result, liquid ammonia purified by efficiently condensing gaseous ammonia derived from the first adsorption tower 41, the second adsorption tower 42, or the third adsorption tower 43 can be obtained, and the liquid can be obtained. The purity of the ammonia can be increased. When the temperature at the time of condensation with respect to gaseous ammonia in the condenser 5 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.

  In addition, the condenser 5 condenses gaseous ammonia derived from the first adsorption tower 41, the second adsorption tower 42, or the third adsorption tower 43 under a pressure of 0.007 to 2.0 MPa to condense the gas phase component. It is preferable to be configured to be separated into a liquid phase component. When the pressure at the time of condensation with respect to gaseous ammonia in the capacitor | condenser 5 is less than 0.007 MPa, since the temperature which condenses ammonia becomes low, much energy is needed for cooling, and 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 5 condenses part of the gaseous ammonia derived from the first adsorption tower 41, the second adsorption tower 42, or the third adsorption tower 43 to generate a gas phase component. Since it is separated into a liquid phase component, highly volatile impurities can be separated and removed as a gas phase component to obtain liquid ammonia purified as a liquid phase component. 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 partial condensation in the capacitor 5, 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 5 not only provides high-purity ammonia in a short time but also has a great energy advantage. Recognize.

  The liquid ammonia obtained as the liquid phase component by the partial condensation in the capacitor 5 is quickly derived from the capacitor 5, and the operation of the capacitor 5 is performed so that only the uncondensed gas phase component exists in the capacitor 5. Is necessary to obtain high-purity ammonia.

  The capacitor 5 is connected to a 20th pipe 90 provided with a 20th valve 901 and a 21st pipe 91 provided with a 21st valve 911. The twentieth pipe 90 is connected between the capacitor 5 and the recovery tank 61.

  In the capacitor 5, highly volatile impurities separated and removed from ammonia as a gas phase component are discharged out of the system through the 21st pipe 91 with the 21st valve 911 being opened. In the capacitor 5, the liquid ammonia obtained as the liquid phase component is supplied to the recovery tank 61 through the 20th pipe 90 with the 20th valve 901 being opened.

  The recovery tank 61 stores liquid ammonia obtained as a liquid phase component by the condenser 5. The recovery tank 61 is connected to a 22nd pipe 92 that communicates the recovery tank 61 with the outside and serves as a flow path for discharging the gas phase component to the outside. The 22nd pipe 92 is provided with a 22nd valve 921 that opens or closes the flow path in the 22nd pipe 92. In the ammonia purification system 100 of the present embodiment, the volatile impurities from liquid ammonia stored in the recovery tank 61 are removed by opening the 22nd valve 921 with the 20th valve 901 closed. A discharge operation for discharging and removing can be performed. By performing the discharge operation in the recovery tank 61, the purity of the liquid ammonia stored in the recovery tank 61 can be further increased.

  Further, the temperature and pressure of the recovery tank 61 are controlled under constant conditions so that ammonia can be stored in a liquid state. A coolant supply device 64 is connected to the recovery tank 61 and the condenser 5 via a 23rd pipe 93. The coolant supplied from the coolant supply device 64 flows through the 23rd pipe 93, and the recovery tank 61 and the condenser 5 are maintained at a predetermined temperature by the cooling capacity of the coolant.

  A filling device 62 is connected to the recovery tank 61 via a 24th pipe 94 provided with a 24th valve 941. The liquid ammonia stored in the recovery tank 61 is supplied to the filling device 62 through the 24th pipe 94 when the 24th valve 941 is opened. The ammonia thus supplied to the filling device 62 is filled into a product filling container or the like by the filling device 62.

  The ammonia purification system 100 of the present embodiment configured as described above is configured to switch the derivation state of the crude ammonia in accordance with the amount of liquid crude ammonia charged in the raw material storage tank 1, Crude ammonia can be derived from the raw material storage tank 1 with little variation in impurity concentration. As a result, it is possible to prevent large variations in the purity of the finally purified ammonia.

  Further, in the ammonia purification system 100 of the present embodiment, impurities contained in the crude ammonia are adsorbed and removed by the first adsorption tower 41, the second adsorption tower 42, and the third adsorption tower 43 filled with the adsorbent. Impurities (mainly water and organic compounds) contained in the crude ammonia can be efficiently adsorbed and removed. And since the capacitor | condenser 5 partial-degrades the ammonia derived | led-out from the 1st adsorption tower 41, the 2nd adsorption tower 42, or the 3rd adsorption tower 43, and isolate | separates into a gaseous-phase component and a liquid phase component, hydrogen, nitrogen, Highly volatile impurities such as oxygen, argon, carbon monoxide, and carbon dioxide can be separated and removed as gas phase components 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.

  FIG. 2 is a diagram showing a configuration of an ammonia purification system 200 according to the second 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 includes a first distillation column 202 and a second distillation column 203 that function as distillation means instead of the condenser 5 included in the ammonia purification system 100, and further includes an analysis unit 201 and a total condenser 204. Further, the ammonia purification system 200 includes an adsorption unit 4A, and the configuration of the adsorption unit 4A is different from the configuration of the adsorption unit 4 described above. Other configurations in the ammonia purification system 200 are the same as those in the ammonia purification system 100.

  The adsorption unit 4A adsorbs and removes impurities contained in gaseous ammonia derived from the flow rate regulator 63 for purification. In the present embodiment, the adsorption unit 4A includes a first adsorption tower 41A, a second adsorption tower 42A, and a third adsorption tower 43A.

  The first adsorption tower 41A may have any configuration as long as it is filled with an adsorbent capable of adsorbing and removing impurities contained in gaseous ammonia supplied via the flow rate regulator 63. . In the present embodiment, the first adsorption tower 41A is provided with a tower top adsorption area 411A and a tower bottom adsorption area 412A in order from the tower top to the tower bottom (from the upstream to the downstream in the ammonia flow direction). Have a structured.

  The tower top adsorption area 411A and the tower bottom adsorption area 412A are areas filled with at least two kinds of adsorbents selected from five kinds of adsorbents of activated carbon, hydrophilic zeolite, hydrophobic zeolite, silica gel, and activated alumina. is there.

  The tower top adsorption region 411A is an adsorption region mainly for adsorbing and removing water. One or more kinds of porous adsorbents selected from activated carbon, MS-13X, and activated alumina having high adsorption ability for water are contained. It is a filled adsorption area. The tower bottom adsorption region 412A is an adsorption region mainly for adsorbing and removing organic compounds and water, and is a hydrophobic zeolite, hydrophilic zeolite, silica gel, 5 or more carbon atoms having high adsorption ability for organic compounds having less than 5 carbon atoms. This is an adsorption region filled with one or more kinds of porous adsorbents selected from activated carbon having a high adsorption ability for organic compounds and water and MS-13X.

  The second adsorption tower 42A has a structure in which a tower top adsorption region 421A and a tower bottom adsorption region 422A are provided in order from the tower top to the tower bottom (from the upstream side to the downstream side in the ammonia flow direction). . In the second adsorption tower 42A, the tower top adsorption area 421A is configured similarly to the tower top adsorption area 411A of the first adsorption tower 41A, and the tower bottom adsorption area 422A is similar to the tower bottom adsorption area 412A of the first adsorption tower 41A. Composed.

  The third adsorption tower 43A has a structure in which a tower top adsorption area 431A and a tower bottom adsorption area 432A are provided in order from the tower top to the tower bottom (from the upstream side to the downstream side in the ammonia flow direction). . In the third adsorption tower 43A, the tower top adsorption area 431A is configured similarly to the tower top adsorption area 411A of the first adsorption tower 41A, and the tower bottom adsorption area 432A is similar to the tower bottom adsorption area 412A of the first adsorption tower 41A. Composed.

  In the ammonia purification system 200 of the present embodiment, the 18th gaseous ammonia derived from any one of the first adsorption tower 41A, the second adsorption tower 42A, and the third adsorption tower 43A is supplied. The piping 88 includes a 30th piping 210 branched from the 18th piping 88 and connected to the analysis unit 201, and a 19th piping 89 branched from the 18th piping 88 and connected to the first distillation column 202. It is done.

  Ammonia flowing through the eighteenth pipe 88 flows through the thirtieth pipe when the thirtieth valve 2101 is opened, and is introduced into the analysis unit 201.

The analysis unit 201 analyzes the concentration of impurities contained in gaseous ammonia derived from the adsorption unit 4A. The analysis unit 201 includes a gas chromatograph analyzer (GC-PDD: pulse discharge detector) and a cavity ring-down spectrometer (CRDS). Examples of the gas chromatograph analyzer include GC-4000 manufactured by GL Sciences Inc., and examples of the cavity ring-down spectroscopic analyzer include MTO-LP-H ₂ O manufactured by Tiger Optics. Can do.

  In this embodiment, the gaseous ammonia derived from the adsorption unit 4A is analyzed for a highly volatile organic compound (for example, methane) concentration by a gas chromatograph analyzer, and the moisture concentration is analyzed by a cavity ring-down spectrometer. To do. In the ammonia purification system 200, the opening / closing operation of the ammonia flow path with respect to the first distillation column 202 and the second distillation column 203 is controlled based on the analysis result by the analysis unit 201.

  The first distillation column 202 distills and removes low boiling point impurities having a boiling point lower than that of ammonia contained in gaseous ammonia derived from the adsorption unit 4A. The first distillation column 202 forms a bottom space portion 2025, a lower distillation portion 2024, a central space portion 2023, an upper distillation portion 2022, and an upper space portion 2021 in order from the bottom, and a reboiler is installed in the bottom space portion 2025. A capacitor is installed in the space 2021. The reboiler is supplied with a heating medium such as heated water from the outside to support the reboiling of the sample, and the condenser is supplied with a refrigerant such as cooling water from the outside to support the condensation of the sample.

  Gaseous ammonia introduced into the central space portion 2023 of the first distillation column 202 rises in the upper distillation portion 2022 and is rectified by gas-liquid contact with the reflux liquid flowing down. That is, ammonia contained in the rising gas phase is dissolved in the reflux liquid, and low-boiling impurities having a lower boiling point than ammonia dissolved in the reflux liquid are vaporized. At this time, the ammonia that has been condensed and purified by removing low-boiling impurities is flowed into the bottom space portion 2025, and is then derived from the bottom space portion 2025 except for a portion that is refluxed to the upper portion of the upper distillation portion 2022. On the other hand, the low boiling point impurities rise to the upper space 2021 to become concentrated gas, are cooled by the condenser, and are continuously discharged as waste gas.

  The second distillation column 203 distills off high-boiling impurities having a boiling point higher than that of ammonia contained in the ammonia derived from the adsorption unit 4A or the first distillation column 202. The second distillation column 203 has the same structure as the first distillation column 202, and forms a bottom space 2035, a lower distillation unit 2034, a central space 2033, an upper distillation unit 2032, and an upper space 2031 to form a bottom space. The part 2035 is provided with a reboiler, and the upper space part 2031 is provided with a capacitor.

  Ammonia introduced into the central space portion 2033 of the second distillation column 203 moves to the bottom space portion 2035 while making gas-liquid contact with the ammonia gas rising in the lower distillation portion 2034. Therefore, the ammonia gas that has been reboiled and vaporized is purified through the lower distillation section 2034, the central space section 2033, and the upper distillation section 2032 while being in gas-liquid contact with the flowing solution. At this time, the distilled and purified ammonia gas reaches the upper space portion 2031, is then cooled by the condenser, and is led out from the upper space portion 2031. On the other hand, the high boiling point impurities flow down to the bottom space 2035 to become a concentrated liquid, and are discharged from the bottom space 2035 as waste liquid.

  The total condenser 204 condenses the ammonia distilled and purified by the first distillation column 202 and the second distillation column 203 and recovers it as liquid ammonia, and the recovered liquid ammonia is stored in the recovery tank 61. The

  Further, the ammonia purification system 200 of the present embodiment is provided with a 31st pipe 211 and a 32nd valve 2121 provided with a 31st valve 2111 that form a flow path through which ammonia derived from the adsorption unit 4A flows. A thirty-second pipe 212, a thirty-third pipe 213 provided with a thirty-third valve 2131, a thirty-four pipe 214 provided with a thirty-fourth valve 2141, and a thirty-fifth pipe 215 provided with a thirty-fifth valve 2151.

  The 31st pipe 211 has one end connected to a 19th pipe 89 branched from the 18th pipe 88 supplied with gaseous ammonia derived from the adsorption unit 4A, and the other end connected to the first distillation column 202. Connected. The thirty-second pipe 212 is connected between the first distillation column 202 and the second distillation column 203. The 33rd pipe 213 is connected between the second distillation column 203 and the total condenser 204. The 34th piping 214 branches from the 31st piping 211 and is connected to the 32nd piping 212. The thirty-fifth pipe 215 branches from the thirty-second pipe 212 on the downstream side in the ammonia flow direction of the thirty-second pipe 212 from the connection portion to which the thirty-fourth pipe 214 is connected and is connected to the thirty-third pipe 213.

  The 31st valve 2111 is provided in the 31st piping 211 on the downstream side in the ammonia flow direction from the branching portion that branches from the 31st piping 211 to the 34th piping 214. The thirty-second valve 2121 is provided in the thirty-second pipe 212 on the downstream side in the ammonia flow direction from the branching portion that branches from the thirty-second pipe 212 to the thirty-fifth pipe 215. The 33rd valve 2131 is provided in the 33rd piping 213 on the upstream side in the ammonia flow direction from the connection portion to which the 35th piping 215 is connected. The 34th valve 2141 is provided in the 34th piping 214. The 35th valve 2151 is provided in the 35th pipe 215.

  In the ammonia purification system 200 of this embodiment, the opening / closing operation of the ammonia flow path for the first distillation column 202 and the second distillation column 203 is controlled based on the analysis result by the analysis unit 201. Hereinafter, the four control patterns will be specifically described.

  The first control pattern is a control pattern in the case where the analysis result that the concentration of the low boiling point impurities and the high boiling point impurities is less than a predetermined value is obtained by the analysis unit 201. In the first control pattern, the analysis result by the analysis unit 201 indicates that the concentration of the low boiling point impurity is less than a predetermined value (for example, the concentration of methane is 30 ppb) and the concentration of the high boiling point impurity is the predetermined value (for example, moisture content). When the analysis result indicates that the concentration is less than 30 ppb), the 34th valve 2141 and the 35th valve 2151 are opened, and the 31st valve 2111, the 32nd valve 2121 and the 33rd valve 2131 are closed.

  As described above, the ammonia purification system 200 in which the opening / closing operation of the flow path is controlled based on the analysis result by the analysis unit 201, the first distillation column 202 and the second distillation with respect to the ammonia derived from the adsorption unit 4A. The purification operation for distillation removal in the column 203 is not performed, and the ammonia derived from the adsorption unit 4A is passed through the 34th pipe 214, the 32nd pipe 212, the 35th pipe 215, and the 33rd pipe 213 to the full condenser 204. Introduced and recovered as liquid ammonia.

  The second control pattern is a control pattern when the analysis unit 201 obtains an analysis result that the concentration of the low boiling point impurity is equal to or higher than the predetermined value and the concentration of the high boiling point impurity is lower than the predetermined value. . In the second control pattern, the analysis result by the analysis unit 201 indicates that the concentration of the low boiling point impurity is a predetermined value (for example, the concentration of methane is 30 ppb) or more and the concentration of the high boiling point impurity is the predetermined value (for example, moisture content). When the analysis result indicates that the concentration is less than 30 ppb), the 31st valve 2111 and the 35th valve 2151 are opened, and the 32nd valve 2121, the 33rd valve 2131, and the 34th valve 2141 are closed.

  As described above, the ammonia purification system 200 in which the opening / closing operation of the flow path is controlled based on the analysis result by the analysis unit 201 performs distillation removal in the first distillation column 202 with respect to the ammonia derived from the adsorption unit 4A. The purification operation is performed, the purification operation for removing the distillation in the second distillation column 203 is not performed, and ammonia derived from the adsorption unit 4A is supplied to the 31st pipe 211, the 32nd pipe 212, the 35th pipe 215, and the 33rd pipe 213. It is passed through and introduced into the total condenser 204 and recovered as liquid ammonia.

  The third control pattern is a control pattern when the analysis unit 201 obtains an analysis result that the concentration of the low boiling point impurity is less than the predetermined value and the concentration of the high boiling point impurity is equal to or higher than the predetermined value. . In the third control pattern, the analysis result by the analysis unit 201 indicates that the concentration of the low boiling point impurity is less than a predetermined value (for example, the concentration of methane is 30 ppb), and the concentration of the high boiling point impurity is the predetermined value (for example, moisture content). When the analysis result indicates that the concentration is 30 ppb) or more, the 34th valve 2141, the 32nd valve 2121 and the 33rd valve 2131 are opened, and the 31st valve 2111 and the 35th valve 2151 are closed.

  As described above, the ammonia purification system 200 in which the opening / closing operation of the flow path is controlled based on the analysis result by the analysis unit 201 performs distillation removal in the second distillation column 203 with respect to the ammonia derived from the adsorption unit 4A. The purification operation is performed, the purification operation for removing the distillation in the first distillation column 202 is not performed, and the ammonia derived from the adsorption unit 4A is completely reduced by passing through the 34th pipe 214, the 32nd pipe 212, and the 33rd pipe 213. It is introduced into the vessel 204 and recovered as liquid ammonia.

  The fourth control pattern is a control pattern in the case where the analysis result that the concentration of the low boiling point impurity and the high boiling point impurity is equal to or higher than a predetermined value is obtained by the analysis unit 201. In the fourth control pattern, the analysis result by the analysis unit 201 indicates that the concentration of the low boiling point impurity is a predetermined value (for example, the concentration of methane is 30 ppb) or more and the concentration of the high boiling point impurity is the predetermined value (for example, moisture content). When the analysis result indicates that the concentration is 30 ppb) or more, the 31st valve 2111, the 32nd valve 2121 and the 33rd valve 2131 are opened, and the 34th valve 2141 and the 35th valve 2151 are closed.

  As described above, the ammonia purification system 200 in which the opening / closing operation of the flow path is controlled based on the analysis result by the analysis unit 201, the first distillation column 202 and the second distillation with respect to the ammonia derived from the adsorption unit 4A. The purification operation of distillation removal in the tower 203 is performed, and the ammonia derived from the adsorption unit 4A is introduced into the full contractor 204 through the 31st pipe 211, the 32nd pipe 212, and the 33rd pipe 213, and the liquid state Recover as ammonia.

  In the ammonia purification system 200 of the present embodiment configured as described above, the analysis unit 201 analyzes the concentration of impurities contained in the ammonia derived from the adsorption unit 4A, and according to the analysis result, the first distillation column. 202 and the second distillation column 203 can be subjected to a purification operation for removing the distillation, so that an unnecessary purification operation for removing the distillation can be omitted. Can be purified.

  FIG. 3 is a diagram showing a configuration of an ammonia purification system 300 according to the third 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 adsorption unit 301 is different from the configuration of the adsorption unit 4 described above.

  The adsorption unit 301 performs purification by adsorbing and removing impurities contained in gaseous ammonia derived from the flow rate regulator 63. In the present embodiment, the adsorption unit 301 includes a first adsorption tower 3011, a second adsorption tower 3012, and a third adsorption tower 3013.

  The first adsorption tower 3011 has a tower top adsorption layer 30111, a first intermediate adsorption layer 30112, and a second intermediate adsorption layer in order from the tower top to the tower bottom (from the upstream side to the downstream side in the ammonia flow direction). 30113 and a tower bottom adsorbing layer 30114 are stacked.

  The tower top adsorption layer 30111 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, MS-13X (porous synthetic zeolite having a pore size of 9 mm), activated alumina, and the like.

  The first intermediate adsorption layer 30112 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 30112, the second intermediate adsorption layer 30113 is a layer containing a second adsorbent and has a function as a second adsorbent layer. However, although the first intermediate adsorption layer 30112 and the second intermediate adsorption layer 30113 are the same because they are layers containing the second adsorbent, different types of adsorbents are used.

  The tower bottom adsorption layer 30114 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 3011 will be described with a specific example. In the first specific example, the tower top adsorption layer 30111 is a layer containing activated carbon (GG, manufactured by Kuraray Chemical Co., Ltd.) as the first adsorbent, and the first intermediate adsorption layer 30112 is hydrophilic as the second adsorbent. It is a layer containing zeolite (MS-3A, manufactured by Tosoh Corporation), and the second intermediate adsorption layer 30113 is a layer containing silica gel (Sylbead N, manufactured by Mizusawa Chemical Co., Ltd.) as the second adsorbent, The adsorption layer 30114 is a layer containing activated carbon (GG, manufactured by Kuraray Chemical Co., Ltd.) as the third adsorbent.

  In the second specific example, the tower top adsorption layer 30111 is a layer containing activated carbon (GG, manufactured by Kuraray Chemical Co., Ltd.) as the first adsorbent, and the first intermediate adsorption layer 30112 is hydrophilic as the second adsorbent. It is a layer containing zeolite (MS-3A, manufactured by Tosoh Corporation), and the second intermediate adsorption layer 30113 is a layer containing silica gel (Sylbead N, manufactured by Mizusawa Chemical Co., Ltd.) as the second adsorbent, The adsorption layer 30114 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 30111 is a layer containing activated carbon (GG, manufactured by Kuraray Chemical Co., Ltd.) as the first adsorbent, and the first intermediate adsorption layer 30112 is hydrophilic as the second adsorbent. It is a layer containing zeolite (MS-4A, manufactured by Tosoh Corporation), and the second intermediate adsorption layer 30113 is a hydrophobic zeolite (HSZ-300, silica / alumina ratio = 10, manufactured by Tosoh Corporation) as the second adsorbent. The tower bottom adsorption layer 30114 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 30111 is a layer containing activated carbon (GG, manufactured by Kuraray Chemical Co., Ltd.) as the first adsorbent, and the first intermediate adsorption layer 30112 is hydrophilic as the second adsorbent. It is a layer containing zeolite (MS-4A, manufactured by Tosoh Corporation), and the second intermediate adsorption layer 30113 is a hydrophobic zeolite (HSZ-300, silica / alumina ratio = 10, manufactured by Tosoh Corporation) as the second adsorbent. The tower bottom adsorption layer 30114 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 3012 has a tower top adsorption layer 30121, a first intermediate adsorption layer 30122, 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). 30123 and a tower bottom adsorbing layer 30124 are stacked. The tower top adsorption layer 30121 is a layer containing the first adsorbent, which is configured in the same manner as the tower top adsorption layer 30111 of the first adsorption tower 3011 described above, and has a function as a first adsorbent layer. The first intermediate adsorption layer 30122 is a layer including the second adsorbent, which is configured similarly to the first intermediate adsorption layer 30112 of the first adsorption tower 3011 described above, and has a function as a second adsorbent layer. The second intermediate adsorption layer 30123 is a layer including the second adsorbent, which is configured similarly to the second intermediate adsorption layer 30113 of the first adsorption tower 3011 described above, and has a function as a second adsorbent layer. The tower bottom adsorption layer 30124 is a layer containing a third adsorbent, which is configured in the same manner as the tower bottom adsorption layer 30114 of the first adsorption tower 3011 described above, and has a function as a third adsorbent layer.

  The third adsorption tower 3013 has a tower top adsorption layer 30131, a first intermediate adsorption layer 30132, and a second intermediate adsorption layer in order from the tower top to the tower bottom (from the upstream side to the downstream side in the ammonia flow direction). 30133 and a tower bottom adsorbing layer 30134 are stacked. The tower top adsorption layer 30131 is a layer including the first adsorbent, which is configured in the same manner as the tower top adsorption layer 30111 of the first adsorption tower 3011 described above, and has a function as a first adsorbent layer. The first intermediate adsorption layer 30132 is a layer including the second adsorbent, which is configured similarly to the first intermediate adsorption layer 30112 of the first adsorption tower 3011 described above, and has a function as a second adsorbent layer. The second intermediate adsorption layer 30133 is a layer including the second adsorbent, which is configured in the same manner as the second intermediate adsorption layer 30113 of the first adsorption tower 3011 described above, and has a function as a second adsorbent layer. The tower bottom adsorption layer 30134 is a layer containing a third adsorbent, which is configured similarly to the tower bottom adsorption layer 30114 of the first adsorption tower 3011 described above, and has a function as a third adsorbent layer.

  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 3011, the second adsorption tower 3012, and the third adsorption tower 3013 adsorb and remove impurities contained in the crude ammonia, the impurities (mainly water and organic compounds) contained in the crude ammonia are efficiently adsorbed. Can be removed. Since the condenser 5 degenerates the ammonia derived from the first adsorption tower 3011, the second adsorption tower 3012, or the third adsorption tower 3013 and separates it into a gas phase component and a liquid phase component, hydrogen, nitrogen , Oxygen, argon, carbon monoxide, carbon dioxide and other highly volatile impurities can be separated and removed as gas phase components 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.

  In addition, the first adsorption tower 3011, the second adsorption tower 3012, and the third adsorption tower 3013 of the adsorption unit 301 have a tower top adsorption layer containing a first adsorbent from the upstream side to the downstream side in the flow direction of the crude ammonia. 30111, 30121, 30131, first intermediate adsorption layers 30112, 30122, 30132 containing a second adsorbent, second intermediate adsorption layers 30113, 30123, 30133 containing a second adsorbent, and tower bottom adsorption containing a third adsorbent Layers 30114, 30124, and 30134 are stacked in this order. Since the tower top adsorbing layers 30111, 30121, and 30131 contain the first adsorbent having high adsorbability with respect to water, the first adsorbing tower 3011, the second adsorbing tower 3012, and the third adsorbing tower 3013 are included. First, most of the ammonia flowing through the column is adsorbed and removed in the tower top adsorption layers 30111, 30121, and 30131. Accordingly, the first intermediate adsorption layers 30112, 30122, 30132, the second intermediate adsorption layers 30113, 30123, 30133, which are arranged downstream of the tower top adsorption layers 30111, 30121, 30131 in the flow direction of ammonia, and the tower bottom Adsorption capacity for organic compounds is sufficiently exhibited in the adsorption layers 30114, 30124, and 30134, and the adsorption removal of impurities from the crude ammonia by the first adsorption tower 3011, the second adsorption tower 3012, and the third adsorption tower 3013 is improved. can do.

  In the present embodiment, as described above, the first adsorption tower 3011, the second adsorption tower 3012, and the third adsorption tower 3013 are capable of adsorbing water, organic compounds having less than 5 carbon atoms, and organic compounds having 5 or more carbon atoms. Have a laminated structure in which different adsorbent layers are laminated. As the first adsorption tower 3011, the second adsorption tower 3012, and the third adsorption tower 3013 configured as described above, the first adsorption tower is configured as an adsorption tower that exhibits an adsorption removal capability for impurities contained in ammonia. An adsorption tower having a tower top adsorbing layer containing an adsorbent and a mixed layer in which the second adsorbent and the third adsorbent are mixed is disposed downstream of the tower top adsorbing layer in the flow direction of the crude ammonia. It is done.

  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.

  In addition, as the first adsorption tower 3011, the second adsorption tower 3012, and the third adsorption tower 3013, the first adsorbent, the second adsorbent, A configuration is also conceivable in which a plurality of adsorption towers individually packed with the third adsorbent are connected in series. 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.

DESCRIPTION OF SYMBOLS 1 Raw material storage tank 2 Control unit 3 Vaporizer 4, 4A, 301 Adsorption unit 5 Capacitor 21 Detection part 22 Derivation switching control part 41, 41A, 3011 1st adsorption tower 42, 42A, 3012 2nd adsorption tower 43, 43A, 3013 Third adsorption tower 61 Recovery tank 62 Filling device 100, 200, 300 Ammonia purification system 201 Analysis unit 202 First distillation tower 203 Second distillation tower 204 Full-condenser

Claims (4)

In an ammonia purification system for purifying crude ammonia containing impurities,
Storage means for storing crude ammonia in the internal space so as to form a gas phase and a liquid phase, and deriving the stored crude ammonia from the gas phase or the liquid phase;
A volume ratio, which is a ratio of the volume of the liquid phase to the volume of the internal space in the storage means, is calculated. Controlling the storage means so that, when the volume ratio is less than the threshold, a derivation control means for controlling the storage means to derive crude ammonia from the gas phase;
Vaporizing means for evaporating a part of the liquid crude ammonia derived from the liquid phase of the storage means and deriving gaseous ammonia;
The gaseous crude ammonia derived from the vapor phase of the storage means or the impurities contained in the gaseous ammonia derived from the vaporization means are adsorbed and removed by an adsorbent to derive gaseous ammonia. An ammonia purification system comprising: an adsorption means.   By separating the 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 the liquid state is purified as a liquid phase component. The ammonia purification system according to claim 1, further comprising a deconcentrating means for obtaining ammonia.   The ammonia purification system according to claim 1, further comprising a distillation means for separating and removing impurities by distilling the ammonia derived from the adsorption means to obtain purified liquid ammonia.   The adsorption means has a plurality of adsorption regions each filled with at least three kinds of adsorbents selected from five kinds of adsorbents of activated carbon, hydrophilic zeolite, hydrophobic zeolite, silica gel, and activated alumina. The ammonia purification system according to any one of claims 1 to 3.

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