KR101901681B1 - System for purifying ammonia - Google Patents

Abstract

The ammonia purification system 200 includes a storage tank 1 for storing crude ammonia, a suction portion 2 for adsorbing and removing impurities in crude ammonia, a first distillation tower 4 for distilling off low boiling point impurities, A condenser 6 for condensing the purified ammonia and recovering the purified ammonia as liquid ammonia, an analysis unit 3 for analyzing the concentration of impurities contained in ammonia derived from the adsorption unit 2, A piping 8 for forming a flow path through which ammonia drawn out from the pipeline 2 flows and a flow path opening and closing part 9 for opening or closing the flow path in the piping 8 and an analysis result by the analysis part 3 And a flow path opening / closing control section (101) for controlling the opening and closing operation of the flow path opening and closing section (9).

Description

[0001] SYSTEM FOR PURIFYING AMMONIA [0002]

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

In the semiconductor manufacturing process and the liquid crystal manufacturing process, ammonia of high purity is used as a treatment agent used for production of a nitride film and the like. Such high purity ammonia is obtained by purifying crude ammonia to remove impurities.

Among the crude ammonia, low-order hydrocarbons such as methane, ethane and propane, high-order hydrocarbons having many carbon atoms, ice fractions, and low-boiling-point gases such as nitrogen, oxygen and argon are contained as impurities. The purity of crude ammonia generally available is on the order of 99.5% by weight.

Depending on the type of process in which ammonia is used in the semiconductor manufacturing process and the liquid crystal manufacturing process, impurities in the ammonia vary in the manner of influence, but the purity of ammonia is required to be 99.9999% by weight or more, more preferably 99.99999% by weight or more.

As a method for removing impurities contained in crude ammonia, there is known a method of adsorbing and removing impurities using an adsorbent such as silica gel, synthetic zeolite, and activated carbon, and a method of distilling off impurities.

For example, Japanese Patent Application Laid-Open No. 2006-206410 discloses a method of adsorbing ammonia, which comprises a first distillation column for removing high boiling point impurities from crude ammonia in a liquid phase, an adsorption tower for adsorbing and removing impurities contained in gaseous ammonia derived from the first distillation column, And a second distillation tower for removing low boiling point impurities from gaseous ammonia derived from the ammonia purification system. Japanese Unexamined Patent Application Publication No. 2003-183021 discloses a method for purifying ammonia by adsorbing moisture contained in crude ammonia in a gaseous phase with an adsorbent comprising barium oxide and then distilling the adsorbent.

In the technique of purifying ammonia disclosed in JP-A-2006-206410 and JP-A-2003-183021, in order to remove ammonia from the liquid to the gas when adsorbing and removing the impurities contained in the crude ammonia, Energy is required, and energy is required to phase-change the ammonia between the liquid and the gas when the impurities are distilled off. Further, since the gas phase ammonia after purification obtained from the distillation column is condensed and recovered as liquid ammonia, energy is also required for this condensation. That is, in the technique of purifying ammonia disclosed in Japanese Patent Application Laid-Open Nos. 2006-206410 and 2003-183021, impurities contained in crude ammonia are adsorbed and distilled off, and further, condensed to obtain purified liquid ammonia In the process up to now, much energy is consumed.

Accordingly, an object of the present invention is to provide an ammonia refining system capable of efficiently refining crude ammonia by suppressing energy consumption.

The present invention relates to a system for purifying crude ammonia containing impurities, comprising: a storage section for storing crude ammonia; an adsorption section for adsorbing and removing impurities contained in crude ammonia derived from the storage section by an adsorbent; A second distillation section for distilling off high boiling point impurities having a boiling point higher than ammonia by distillation; a condensing section for condensing ammonia and recovering the liquid ammonia as liquid ammonia; A first pipeline connected between the adsorption section and the first distillation section as a pipeline for forming a flow path through which the ammonia drawn from the adsorption section flows, A second pipe connected between the first distillation section and the second distillation section, and a second pipe connected between the second distillation section and the condensation section A fourth pipe connected to the second pipe and branched from the first pipe; and a third pipe connected to the second pipe, the third pipe being connected to the second pipe, And a fifth pipe branched from the second pipe and connected to the third pipe; and a flow path opening / closing unit for opening or closing the flow path in the pipe, wherein the first pipe is connected to the fourth pipe And a second valve provided on the downstream side of the branch pipe branching from the first pipe to the fourth pipe in the flow direction of ammonia in the first pipe A second valve and a branch portion branched from the second pipe to the fifth pipe in the second pipe, A fourth valve provided on the upstream side in the flow direction of ammonia with respect to a connecting portion to which the fifth pipe is connected in the third pipe; and a fifth valve provided on the fourth pipe, And a sixth valve installed in the fifth pipe; and an opening / closing unit for opening / closing the flow path of the first to sixth valves based on the analysis result of the analysis unit, And an ammonia purification system.

According to the present invention, an ammonia refining system is provided with a reservoir for storing crude ammonia, a pipe for forming a channel through which ammonia drawn from the adsorption unit flows, an adsorption unit, a first distillation unit, a second distillation unit, A flow path opening / closing portion for opening or closing the flow path in the pipe, and a flow path opening / closing control portion. The adsorbing portion adsorbs and removes impurities contained in the crude ammonia drawn from the storage portion. The first distillation portion distills off low boiling point impurities having a boiling point lower than that of ammonia. The second distillation portion distills away high boiling point impurities having a boiling point higher than ammonia. The condenser condenses the ammonia after removing the impurities and collects it as liquid ammonia. The analyzing unit analyzes the concentration of impurities contained in the ammonia drawn from the adsorption unit. The piping includes a first pipe connected between the adsorption section and the first distillation section, a second pipe connected between the first distillation section and the second distillation section, a third pipe connected between the second distillation section and the condensation section, A fourth pipe branched from the first pipe and connected to the second pipe; and a third pipe branched from the second pipe at a downstream side in the flow direction of ammonia than a connecting portion connected to the fourth pipe in the second pipe, And a fifth pipe connected to the second pipe. The flow path opening and closing part is connected to a first valve provided on the upstream side of the branch pipe branched from the first pipe to the fourth pipe in the flow direction of ammonia in the first pipe and a second valve branched from the first pipe to the fourth pipe in the first pipe A third valve disposed downstream of the branch pipe branched from the second pipe to the fifth pipe in the flow direction of ammonia and a second valve disposed downstream of the branch pipe in the flow direction of ammonia, A fourth valve provided upstream of the connecting portion to which the fifth pipe is connected in the flow direction of ammonia in the third pipe, a fifth valve provided in the fourth pipe, and a sixth valve provided in the fifth pipe.

In the ammonia refining system constituted as described above, first, the adsorbing portion adsorbs and removes impurities contained in the crude ammonia derived from the storage portion. A part of the ammonia led out from the adsorption part is introduced into the analysis part, and the concentration of the impurity contained in the ammonia is analyzed by the analysis part. The flow path opening / closing control unit controls opening and closing operations of the first to sixth valves installed in the piping through which the ammonia drawn from the adsorption unit flows, based on the analysis result by the analysis unit. In the ammonia purification system of the present invention, the concentration of the impurities contained in the ammonia derived from the adsorption unit is analyzed by the analysis unit, and purification operation of the distillation removal in the first distillation unit and the second distillation unit is performed The purification operation for removing unnecessary distillation can be omitted. As a result, the crude ammonia can be efficiently purified by suppressing the consumption of energy.

In the ammonia purification system of the present invention, when the analysis result of the analysis unit indicates 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 less than the predetermined value, Wherein the first valve, the fifth valve and the sixth valve are opened and the second valve, the third valve and the fourth valve are closed, and the analysis result by the analysis unit is the concentration of the low boiling point impurity The first valve, the second valve, and the sixth valve are opened, and the third valve, the fourth valve, and the fourth valve are opened when the result of the analysis indicates that the concentration of the high boiling point impurity is lower than the predetermined value, The concentration of the low boiling point impurity is lower than a predetermined value and the concentration of the low boiling point impurity is lower than the predetermined value, Wherein said control means opens said first valve, said fifth valve, said third valve and said fourth valve in the case of an analysis result indicating that the concentration of said point impurity is equal to or greater than a predetermined value and closes said second valve and said sixth valve And when the analysis result by the analysis unit is an analysis result indicating that the concentration of the low boiling point impurity is higher than a predetermined value and the concentration of the high boiling point impurity is higher than a predetermined value, the first valve, the second valve, And the fourth valve is opened, and the fifth valve and the sixth valve are closed.

According to the present invention, the flow path opening / closing control section controls the following four patterns based on the analysis result by the analysis section. In the first pattern, when the analysis result by the analysis unit indicates 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 less than the predetermined value in the first pattern, 6 valve is opened, and control is performed to close the second valve, the third valve, and the fourth valve. Thus, in the ammonia refining system, ammonia derived from the adsorption unit is not refined and removed in the first distillation unit and the second distillation unit, and ammonia derived from the adsorption unit is refined in the first pipe, , The second pipe, the fifth pipe, and the third pipe may be introduced into the condensing portion to be recovered as liquid ammonia.

In the second pattern, when the analysis result by the analyzing section indicates that the concentration of the low-boiling-point impurity is higher than the predetermined value and the concentration of the high-boiling-point impurity is lower than the predetermined value, And the sixth valve are opened, and the third valve, the fourth valve and the fifth valve are closed. Thus, the ammonia refining system performs purification operation of distillation and removal in the first distillation section with respect to ammonia drawn out from the adsorption section, and purifies the ammonia discharged from the adsorption section without purification operation of distillation removal in the second distillation section The first pipe, the second pipe, the fifth pipe, and the third pipe may be introduced into the condenser to recover the ammonia as liquid ammonia.

In the third pattern, when the analysis result by the analyzing section indicates that the concentration of the low-boiling-point impurity is lower than the predetermined value and the concentration of the high-boiling-point impurity is higher than the predetermined value, , The third valve and the fourth valve are opened, and the second valve and the sixth valve are closed. With this, the ammonia refining system performs purification operation of distillation removal in the second distillation section with respect to ammonia derived from the adsorption section, and purifies the ammonia discharged from the adsorption section without purification operation of the distillation removal in the first distillation section The first pipe, the fourth pipe, the second pipe and the third pipe can be introduced into the condensing portion and recovered as liquid ammonia.

In the fourth pattern, when the analysis result by the analyzing unit indicates that the concentration of the low-boiling-point impurity is higher than the predetermined value and the concentration of the high-boiling-point impurity is higher than the predetermined value, , The third valve and the fourth valve are opened, and the fifth valve and the sixth valve are closed. Thus, the ammonia refining system performs purifying operation of distillation and elimination in the first distillation section and the second distillation section with respect to ammonia derived from the adsorption section, and the ammonia derived from the adsorption section is returned to the first pipeline, And the third pipe may be introduced and introduced into the condensing section to be recovered as liquid ammonia.

Further, in the ammonia purification system of the present invention, the pipeline is connected between the adsorption section and the storage section, and ammonia drawn out from the adsorption section flows until the analysis by the analysis section is completed, toward the storage section And a sixth pipe forming a flow path.

According to the present invention, the piping forming the flow path through which the ammonia drawn out from the adsorption section flows is connected between the adsorption section and the storage section, and ammonia drawn out from the adsorption section until the analysis by the analysis section is terminated is directed toward the storage section And a sixth pipe forming a flow path for circulation. Thus, the ammonia drawn out from the adsorption section can be returned to the storage section via the sixth pipe until the analysis by the analysis section is completed.

Further, in the ammonia refining system of the present invention, the adsorbing portion has a plurality of adsorbing portions for adsorbing and removing impurities contained in crude ammonia by an adsorbent, and the plurality of adsorbing portions are separated from each other by the crude ammonia .

According to the present invention, the adsorption section has a plurality of adsorption sections for adsorbing and removing impurities contained in crude ammonia by an adsorbent, and crude ammonia derived from the storage section is introduced into the plurality of adsorption sections separately. As a result, while the impurities contained in the crude ammonia are adsorbed and removed by one adsorption unit, the other adsorption units that have been used can be regenerated so that the adsorption removal operation can be performed again by the other adsorption units that have been used.

Further, in the ammonia purification system of the present invention, the analyzer may include a gas chromatograph analyzer and a cavity ring down spectrometer, and the ammonia drawn from the adsorbent may be analyzed by a gas chromatograph analyzer for methane concentration And analyze the moisture concentration with a cavity ring down spectrometer.

According to the present invention, the analyzing unit includes a gas chromatograph analyzer and a cavity ring down spectrometer. Then, ammonia derived from the adsorption part is analyzed for methane concentration by a gas chromatograph analyzer, and moisture concentration is analyzed by a cavity ring down spectrometer. By this, the flow path opening / closing control section can determine, based on the analysis result indicated by the concentration of methane, which is a low boiling point impurity analyzed by the gas chromatograph analyzer, and the concentration of moisture, which is a high boiling point impurity analyzed by the cavity ring down spectrometer Closing operation of the first to sixth valves can be controlled.

Further, in the ammonia purification system of the present invention, it is preferable that the adsorbent is at least one inorganic porous adsorbent selected from synthetic zeolite and activated carbon.

According to the present invention, the adsorbent used in the adsorption part is at least one inorganic porous adsorbent selected from synthetic zeolite and activated carbon. By using synthetic zeolite as an adsorbent, moisture contained in crude ammonia can be efficiently adsorbed and removed. By using activated carbon as an adsorbent, hydrocarbon-based impurities contained in crude ammonia can be efficiently adsorbed and removed.

The objects, features, and advantages of the present invention will become more apparent from the following detailed description and drawings.
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a view showing a configuration of an ammonia purification system according to an embodiment of the present invention; FIG.
2 is a block diagram showing the configuration of the ammonia purification system.
Fig. 3 is a diagram showing the distribution state of ammonia in the piping when the analysis result by the analysis unit is that the concentration of the low boiling point impurity and the high boiling point impurity is less than the predetermined value.
FIG. 4 is a diagram showing the distribution state of ammonia in the piping when the analysis result by the analysis unit is that the concentration of the low-boiling-point impurity is higher than a predetermined value and the concentration of the high-boiling-point impurity is lower than a predetermined value.
5 is a diagram showing the distribution state of ammonia in the piping when the analysis result by the analysis unit is that the concentration of the low boiling point impurity is lower than the predetermined value and the concentration of the high boiling point impurity is higher than the predetermined value.
Fig. 6 is a diagram showing the flow state of ammonia in the piping when the analysis result by the analysis unit is that the concentration of the low boiling point impurities and the high boiling point impurities is a predetermined value or more.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

1 is a view showing a configuration of an ammonia purification system 200 according to an embodiment of the present invention. 2 is a block diagram showing the structure of the ammonia purification system 200. As shown in FIG.

The ammonia refining system 200 of the present embodiment is a system for purifying crude ammonia containing impurities. The crude ammonia contains low-order hydrocarbons such as methane, ethane and propane, higher-order hydrocarbons having a large number of carbon atoms, moisture, and low-boiling-point gases such as nitrogen, oxygen and argon as impurities. That is, crude ammonia includes low boiling point hydrocarbons having a boiling point lower than that of ammonia (boiling point -33.44 DEG C), low boiling point impurities such as low boiling point gases, and high boiling point impurities such as high-order hydrocarbons and water having boiling points higher than ammonia.

The ammonia refining system 200 includes a storage tank 1 as a reservoir, an adsorption unit 2, an analysis unit 3, a first distillation tower 4 as a first distillation unit, a second distillation tower 5 as a second distillation unit, A pipe 8 for forming a channel through which the ammonia drawn out from the adsorption unit 2 flows, a channel opening and closing unit 9 for opening or closing the channel in the pipe 8, and a control unit 10 ).

The storage tank 1 is for storing crude ammonia. The storage tank 1 is not particularly limited as long as it is a thermal insulation container having pressure resistance and corrosion resistance. The storage tank 1 is controlled by the operation condition control unit 102 of the control unit 10 so that the crude ammonia is stored as liquid ammonia and the temperature and the pressure are kept constant. A vapor phase is formed in the upper part of the storage tank 1 with liquid ammonia stored therein. When crude ammonia is drawn from the storage tank 1 to the adsorption section 2, it may be derived as liquid ammonia. In this embodiment, crude ammonia is derived from the gas phase as gaseous ammonia. The supply pipe 11 is connected between the storage tank 1 and the adsorption section 2 and the crude ammonia derived from the storage tank 1 flows through the supply pipe 11 and flows into the first Is supplied to the adsorption tower (21) or the second adsorption tower (22). When the crude ammonia is supplied to the first adsorption tower 21 or the second adsorption tower 22, the opening and closing operation of the flow passage is performed by the supply valves 12 and 13 provided in the supply pipe 11. [

The adsorption unit 2 adsorbs and removes impurities contained in gaseous ammonia derived from the storage tank 1 by the adsorbent. In this embodiment, the adsorption section 2 includes a first adsorption tower 21 and a second adsorption tower 22. [ The first adsorption tower (21) and the second adsorption tower (22) have the same constitution, and gaseous ammonia derived from the storage tank (1) in the separated state is introduced. As a result, while the impurities contained in the crude ammonia are adsorbed and removed by the first adsorption tower 21, the second adsorption tower (for example, 22 can be regenerated.

Examples of the adsorbent to be charged in the first adsorption tower 21 and the second adsorption tower 22 include inorganic porous adsorbents such as synthetic zeolite and activated carbon. Examples of the synthetic zeolite include MS-3A (pore diameter 3 Å), MS-4A (pore diameter 4 Å), MS-5A (pore diameter 5 Å) and MS-13X (pore diameter 9 Å) having different pore diameters. In this embodiment, MS-13X, which is excellent in hydrocarbon and water adsorbing ability, MS-3A, which has excellent water adsorbing ability, and MS-4A + MS-5A, which has excellent hydrocarbon adsorbing ability, are stacked as adsorbents. The mixing ratio of the adsorbent thus obtained is 1: 1: 1 as MS-13X: MS-3A (MS-4A + MS-5A).

The temperature and pressure of the first adsorption tower 21 and the second adsorption tower 22 are controlled by the operating condition control unit 102 of the control unit 10. [ Specifically, the temperatures of the first adsorption tower 21 and the second adsorption tower 22 are controlled at 0 to 60 캜, and the pressure is controlled at 0.1 to 1.0 MPa. When the temperatures of the first adsorption tower 21 and the second adsorption tower 22 are lower than 0 캜, it is necessary to cool the adsorption heat to be removed at the time of adsorption and removal of the impurities, thereby lowering the energy efficiency. If the temperature of the first adsorption tower 21 and the second adsorption tower 22 exceeds 60 캜, there is a fear that the adsorption ability of the impurities by the adsorbent is lowered. In addition, when the pressures of the first adsorption tower 21 and the second adsorption tower 22 are less than 0.1 MPa, there is a possibility that the adsorption ability of impurities by the adsorbent is lowered. When the pressure of the first adsorption tower 21 and the second adsorption tower 22 exceeds 1.0 MPa, a large amount of energy is required to maintain the pressure at a constant pressure, which may lower energy efficiency.

The linear velocity (linear velocity) in the first adsorption tower 21 and the second adsorption tower 22 is the amount by which crude ammonia per unit time is supplied to the first adsorption tower 21 or the second adsorption tower 22 by NTP It is preferable that the range of the value obtained by dividing by the gas cross-sectional area of the first adsorption tower 21 or the second adsorption tower 22 is 0.1 to 5.0 m / sec. If the linear velocity is less than 0.1 m / sec, it is not preferable because a long time is required for the adsorption and removal of impurities, and when the linear velocity exceeds 5.0 m / sec, the adsorption heat generated at the time of adsorbing and removing impurities is sufficiently removed The adsorbing ability of the impurities due to the adsorbent may be deteriorated.

The analyzing unit 3 analyzes the concentration of impurities contained in the gaseous ammonia derived from the adsorption unit 2. [ In the present embodiment, the analyzing section 3 includes a gas chromatograph analyzer (GC-PDD: pulse discharge detector) 31 and a cavity ring down spectrometer (CRDS) 32. Examples of the gas chromatograph analyzer 31 include GC-4000 (manufactured by Dieru Science Ltd.), and the cavity ring down spectrometer 32 includes, for example, MTO-LP-H ₂ O (manufactured by Tiger Optics).

In this embodiment, the gas phase ammonia led out from the adsorption unit 2 is analyzed for methane concentration by the gas chromatograph analyzer 31, and the concentration of water is analyzed by the cavity ring down spectrometer 32. As a result, the flow path opening / closing control section 101, which will be described later, controls the concentration of methane, which is a low boiling point impurity analyzed by the gas chromatograph analyzer 31, and the concentration of the high boiling point impurity, which is analyzed by the cavity ring down spectrometer 32 It is possible to control the opening / closing operation of the flow path opening / closing unit 9 based on the analysis result expressed by the concentration of water.

The first distillation column 4 distills off low boiling point impurities having a lower boiling point than ammonia contained in gaseous ammonia led from the adsorption section 2. The operating conditions such as temperature and pressure in the first distillation column 4 are controlled by the operating condition control unit 102 of the control unit 10. [ The first distillation column 4 has a bottom space portion 45, a bottom distillation portion 44, a central space portion 43, an upper distillation portion 42 and an upper space portion 41 in this order from the bottom, A reboiler 45a is installed in the space portion 45 and a condenser 41a is provided in the upper space portion 41. [ A heating medium such as heating water is supplied from the outside to the reboiler 45a to support the reboiler of the sample. The refrigerant such as cooling water is supplied from the outside to the condenser 41a to support the condensation of the sample .

The gaseous ammonia introduced into the central space portion 43 of the first distillation column 4 is rectified by gas-liquid contact with the reflux liquid flowing upward in the upper distillation section 42. That is, the ammonia contained in the rising gas phase is dissolved and refluxed in the reflux liquid, and low boiling point impurities having lower boiling point than the ammonia dissolved in the reflux liquid are vaporized. At this time, the ammonia condensed and purified by removing low boiling point impurities is drained from the bottom space portion 45, except for a portion which is refluxed to the upper portion of the upper distillation portion 42. On the other hand, the low boiling point impurities rise to the upper space portion 41 to become a thickened gas, cooled by the condenser 41a, and discharged continuously as waste gas.

The second distillation column 5 distills away high boiling point impurities having a boiling point higher than ammonia contained in the ammonia derived from the adsorption unit 2 or the first distillation column 4. The operating conditions such as temperature and pressure in the second distillation column 5 are controlled by the operating condition control unit 102 of the control unit 10. [ The second distillation column 5 has the same structure as the first distillation column 4 and includes a bottom space portion 55, a bottom distillation portion 54, a central space portion 53, an upper distillation portion 52, A reboiler 55a is installed in the bottom space portion 55 and a condenser 51a is provided in the upper space portion 51. The reboiler 55a is installed in the bottom space portion 55,

The ammonia introduced into the central space portion 53 of the second distillation tower 5 moves to the bottom space portion 55 while being in vapor-liquid contact with the ammonia gas rising in the lower distillation portion 54. Thus, the ammonia gas that has been reboiled and vaporized is purified through the lower distillation section 54, the central space section 53, and the upper distillation section 52 while being in gas-liquid contact with the solution. At this time, the distilled and purified ammonia gas reaches the upper space portion 51, is cooled by the condenser 51a, and is led out from the upper space portion 51. On the other hand, the high boiling point impurities flow down into the bottom space portion 55 to become a concentrated liquid, and are discharged from the bottom space portion 55 as a waste liquid.

The condenser 6 condenses the purified ammonia as liquid ammonia, and the recovered liquid ammonia is stored in the recovery tank 61. The operating condition such as the temperature in the condenser 6 is controlled by the operating condition control unit 102 of the control unit 10. [

The ammonia refining system 200 of the present embodiment is provided with a pipe 8 for forming a flow path through which the ammonia drawn from the adsorption section 2 flows. The pipe 8 is connected to the first pipe 81, the second pipe 82, the third pipe 83, the fourth pipe 84, the fifth pipe 85, the sixth pipe 86, 7 < / RTI > The first pipe 81 is connected between the adsorption section 2 and the first distillation column 4. The second pipe 82 is connected between the first distillation column 4 and the second distillation column 5. And the third pipe 83 is connected between the second distillation tower 5 and the condenser 6. [ The fourth pipe 84 branches from the first pipe 81 and is connected to the second pipe 82. The fifth pipe 85 is branched from the second pipe 82 at the downstream side in the flow direction of ammonia and is connected to the third pipe 83 in the second pipe 82 rather than the connecting portion to which the fourth pipe 84 is connected do. The sixth piping 86 is connected between the adsorption section 2 and the storage tank 1 and ammonia drawn from the adsorption section 2 until the analysis by the analysis section 3 is terminated is stored in the storage tank 1 To form a flow path through which the gas flows. In the gas chromatograph analyzer 31, a time of about 10 minutes is required until the analysis is completed. In the cavity ring-down spectrometer 32, a time of about 20 to 30 minutes is required until the analysis is completed. The ammonia drawn from the adsorption section 2 is returned to the storage tank 1 via the sixth pipe 86 until the analysis by the analysis section 3 is completed by the sixth pipe 86 . The seventh pipe 87 is branched from the first pipe 81 and connected to the analyzing unit 3 so that a part of the ammonia drawn out from the adsorbing unit 2 forms a flow path for flowing toward the analyzing unit 3 .

The ammonia refining system 200 of the present embodiment is provided with a flow path opening and closing part 9 for opening or closing the flow path of the pipe 8. The flow path opening and closing part 9 includes a first valve 91, a second valve 92, a third valve 93, a fourth valve 94, a fifth valve 95, a sixth valve 96, 7 valve 97, and an eighth valve 98, as shown in Fig. The first valve 91 is provided upstream of the branch portion branched from the first pipe 81 to the fourth pipe 84 in the first pipe 81 in the flow direction of ammonia. The second valve 92 is provided downstream of the branch portion branched from the first pipe 81 to the fourth pipe 84 in the first pipe 81 in the flow direction of ammonia. The third valve 93 is provided downstream of the branch portion branched from the second pipe 82 to the fifth pipe 85 in the second pipe 82 in the flow direction of ammonia. The fourth valve 94 is provided on the upstream side of the third pipe 83 in the flow direction of the ammonia, rather than the connecting portion to which the fifth pipe 85 is connected. The fifth valve (95) is installed in the fourth pipe (84). The sixth valve (96) is installed in the fifth pipe (85). The seventh valve (97) is installed in the sixth pipe (86). The eighth valve (98) is installed in the seventh pipe (87).

In the ammonia refining system 200 of the present embodiment configured as described above, first, the adsorption unit 2 adsorbs and removes impurities contained in the crude ammonia derived from the storage tank 1. At this time, the flow path opening / closing control section 101 of the control section 10 includes a first valve 91, a second valve 92, a third valve 93, a fourth valve 94, a fifth valve 95, And the sixth valve 96 are closed and the seventh valve 97 and the eighth valve 98 are opened. As a result, a part of ammonia (a very small amount of ammonia necessary for analysis by the analysis unit 3) derived from the adsorption unit 2 flows through the seventh pipe 87 and is introduced into the analysis unit 3, And the concentration of the impurities contained in the ammonia is analyzed by the portion (3). The remaining ammonia excluding the extremely small amount of ammonia introduced into the analyzing section 3 out of the ammonia led out from the adsorption section 2 is discharged to the sixth piping 86 And returns to the storage tank 1.

In the ammonia refining system 200 according to the present embodiment, the flow path opening / closing control unit 101 of the control unit 10 calculates the flow rate of the air in the flow path switching unit 9 on the basis of the analysis result of the analysis unit 3 And controls opening and closing operations of opening or closing the flow path. In the ammonia refining system 200, the concentration of impurities contained in ammonia drawn from the adsorption unit 2 is analyzed by the analyzing unit 3 and the first distillation tower 4 and the second distillation tower 5, It is possible to omit purification operation for distillation removal unnecessary, and thereby, the consumption of energy can be suppressed and the crude ammonia can be efficiently purified.

Next, more specific refining operation in the ammonia refining system 200 of the present embodiment will be described. In the ammonia refining system 200 of the present embodiment, the flow path opening / closing control section 101 performs the following four patterns of control on the basis of the analysis result by the analysis section 3.

<First Pattern>

Fig. 3 is a diagram showing the distribution state of ammonia in the pipe 8 when the analysis result by the analysis unit 3 is that the concentration of the low boiling point impurity and the high boiling point impurity is less than the predetermined value. In the first pattern, the flow path opening / closing control section 101 determines that the analysis result by the analyzing section 3 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) The first valve 91, the fifth valve 95 and the sixth valve 96 are opened and the second valve 92 is opened when the result of the analysis indicates that the predetermined value (for example, the concentration of water is less than 30 ppb) The third valve 93, the fourth valve 94, and the seventh valve 97 are closed. The flow path opening and closing control section 101 is connected to the analysis section 3 from the first pipeline 81 and connected to the seventh pipeline 87 through which a very small amount of ammonia required for analysis by the analysis section 3 flows, And the eighth valve (98) installed in the control valve is always opened.

The ammonia refining system 200 in which the opening and closing operation of each valve of the flow path opening and closing part 9 is controlled on the basis of the analysis result by the analyzing part 3 as described above is used for the ammonia removal from the adsorption part 2, Ammonia derived from the adsorption section 2 is supplied to the first pipe 81, the fourth pipe 84 and the second pipe (not shown) without performing purification operation for distillation removal in the first distillation column 4 and the second distillation column 5 82, the fifth piping 85 and the third piping 83 can be flown into the condenser 6 to be recovered as liquid ammonia.

<Second Pattern>

4 is a diagram showing the distribution state of ammonia in the pipe 8 when the analysis result by the analysis unit 3 is that the concentration of the low boiling point impurity is higher than the predetermined value and the concentration of the high boiling point impurity is lower than the predetermined value. In the second pattern, the flow path opening / closing control section 101 determines that the analysis result by the analyzing section 3 indicates that the concentration of the low boiling point impurity is equal to or higher than a predetermined value (for example, the concentration of methane is 30 ppb) The first valve 91, the second valve 92 and the sixth valve 96 are opened and the third valve 93 is opened when the result of the analysis indicates that the predetermined value (for example, the concentration of water is less than 30 ppb) The fourth valve 94, the fifth valve 95, and the seventh valve 97 are closed. The flow path opening and closing control section 101 is connected to the analysis section 3 from the first pipeline 81 and connected to the seventh pipeline 87 through which a very small amount of ammonia required for analysis by the analysis section 3 flows, And the eighth valve (98) installed in the control valve is always opened.

The ammonia refining system 200 in which the opening and closing operation of each valve of the flow path opening and closing part 9 is controlled on the basis of the analysis result by the analyzing part 3 as described above is used for the ammonia removal from the adsorption part 2, The purification operation of the distillation removal in the first distillation column 4 is performed and the purification operation of the distillation removal in the second distillation column 5 is not performed and the ammonia drawn out from the adsorption section 2 is returned to the first pipe 81, The second piping 82, the fifth piping 85 and the third piping 83 may be introduced into the condenser 6 to be recovered as liquid ammonia.

<Third Pattern>

5 is a diagram showing the distribution state of ammonia in the pipe 8 when the analysis result by the analysis unit 3 is 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 not less than the predetermined value. In the third pattern, the flow path opening / closing control unit 101 determines that the analysis result by the analyzing unit 3 is that the concentration of the low boiling point impurity is less than a predetermined value (for example, the concentration of methane is 30 ppb) The first valve 91, the fifth valve 95, the third valve 93 and the fourth valve 94 are opened in the case of an analysis result indicating that the predetermined value (for example, the concentration of water is 30 ppb) The second valve 92, the sixth valve 96, and the seventh valve 97 are closed. The flow path opening and closing control section 101 is connected to the analysis section 3 from the first pipeline 81 and connected to the seventh pipeline 87 through which a very small amount of ammonia required for analysis by the analysis section 3 flows, And the eighth valve (98) installed in the control valve is always opened.

The ammonia refining system 200 in which the opening and closing operations of the respective valves of the flow path opening and closing part 9 are controlled on the basis of the analysis result by the analyzing part 3 as described above is used for the ammonia removal from the adsorption part 2, The purification operation of the distillation removal in the first distillation column 5 is carried out and the ammonia drawn out from the adsorption section 2 is introduced into the first pipe 81 and the second pipe 81, The fourth piping 84, the second piping 82 and the third piping 83 can be flown into the condenser 6 to be recovered as liquid ammonia.

<Fourth pattern>

Fig. 6 is a diagram showing the distribution state of ammonia in the pipe 8 when the analysis result by the analysis unit 3 is that the concentration of the low boiling point impurities and the high boiling point impurities is a predetermined value or more. In the fourth pattern, the flow path opening / closing control section 101 determines that the analysis result by the analyzing section 3 indicates that the concentration of the low boiling point impurity is equal to or higher than a predetermined value (for example, the concentration of methane is 30 ppb) The first valve 91, the second valve 92, the third valve 93 and the fourth valve 94 are opened in the case of the analysis result showing that the predetermined value (for example, the concentration of water is 30 ppb) The fifth valve 95, the sixth valve 96, and the seventh valve 97 are closed. The flow path opening and closing control section 101 is connected to the analysis section 3 from the first pipeline 81 and connected to the seventh pipeline 87 through which a very small amount of ammonia required for analysis by the analysis section 3 flows, And the eighth valve (98) installed in the control valve is always opened.

The ammonia refining system 200 in which the opening and closing operation of each valve of the flow path opening and closing part 9 is controlled on the basis of the analysis result by the analyzing part 3 as described above is used for the ammonia removal from the adsorption part 2, The ammonia discharged from the adsorption section 2 is supplied to the first pipe 81, the second pipe 82 and the third pipe 83 Can be circulated and introduced into the condenser 6 to be recovered as liquid ammonia.

The present invention may be embodied in other forms without departing from the spirit or essential characteristics thereof. Therefore, the above-described embodiment is not limited to simple examples in all respects, and the scope of the present invention is shown in the claims, and is not limited to the details of the specification. Modifications and variations falling within the scope of the claims are all within the scope of the present invention.

1: Storage tank 2: Adsorption section
3: Analysis part 4: 1st distillation tower
5: second distillation column 6: condenser
7: Condenser for analysis 8: Piping
9: flow path opening and closing unit 10:
21: first adsorption tower 22: second adsorption tower
31: Gas chromatograph analyzer 32: Cavity ring down spectrometer
101: flow path opening / closing control section 102:
200: Ammonia Purification System

Claims (17)

A system for purifying crude ammonia comprising impurities comprising:
A storage unit for storing the crude ammonia;
A suction unit for adsorbing and removing impurities contained in the crude ammonia derived from the storage part by an adsorbent;
A first distillation unit for distilling off low boiling point impurities having a lower boiling point than ammonia;
A second distillation unit for distilling off high boiling point impurities having a boiling point higher than that of ammonia;
A condenser for condensing ammonia to recover as liquid ammonia;
An analyzer for analyzing the concentration of impurities contained in ammonia drawn from the adsorption unit;
A pipe for forming a flow path through which ammonia drawn out from the adsorption section flows,
A first pipe connected between the adsorption unit and the first distillation unit,
A second pipe connected between the first distillation section and the second distillation section,
A third pipe connected between the second distillation section and the condensing section,
A fourth pipe branched from the first pipe and connected to the second pipe,
And a fifth pipe branched from the second pipe and connected to the third pipe at a downstream side in the flow direction of ammonia than a connecting portion to which the fourth pipe is connected in the second pipe;
A flow path opening / closing part for opening or closing the flow path of the pipe,
A first valve installed upstream of the branch portion branched from the first pipe to the fourth pipe in the flow direction of the ammonia in the first pipe,
A second valve installed downstream of the branch portion branched from the first pipe to the fourth pipe in the flow direction of ammonia in the first pipe,
A third valve installed downstream of the branch portion branched from the second pipe to the fifth pipe in the flow direction of ammonia in the second pipe,
A fourth valve disposed upstream of the connecting portion to which the fifth pipe is connected in the third pipe in the flow direction of ammonia,
A fifth valve installed in the fourth pipe,
And a sixth valve installed in the fifth pipe; And
And an opening / closing control part for controlling opening and closing operations of opening and closing the flow paths of the first to sixth valves based on the analysis result by the analyzing part. The method according to claim 1,
The flow path opening /
Wherein the concentration of the low boiling point impurity in the analysis result by the analyzing section is lower than a first predetermined value which is a predetermined value for determining whether or not purification operation of distillation removal is to be performed in the first distillation section, The fifth valve, and the sixth valve when the predetermined value is less than a second predetermined value, which is a predetermined value, which is a reference value for determining whether or not purification operation of distillation removal is performed in the second distillation section, And controls closing of the second valve, the third valve, and the fourth valve,
When the concentration of the low boiling point impurity is equal to or higher than the first predetermined value and the concentration of the high boiling point impurity is lower than the second predetermined value in the analysis result by the analysis section, the first valve, the second valve, The third valve, the fourth valve, and the fifth valve are closed,
When the concentration of the low boiling point impurity is lower than the first predetermined value and the concentration of the high boiling point impurity is equal to or higher than the second predetermined value in the analysis result of the analysis unit, the first valve, the fifth valve, And a control for opening said fourth valve and closing said second valve and said sixth valve,
When the concentration of the low boiling point impurity is higher than or equal to the first predetermined value and the concentration of the high boiling point impurity is equal to or higher than the second predetermined value in the analysis result by the analyzing section, the first valve, the second valve, And the fourth valve is opened, and the fifth valve and the sixth valve are closed. The method according to claim 1 or 2,
The pipeline includes a sixth pipe connected between the adsorbing portion and the storage portion and forming a flow passage through which the ammonia drawn from the adsorption portion flows until the analysis by the analysis portion is completed, toward the storage portion Ammonia refining system characterized by. 3. The method according to claim 1 or 2,
Wherein the adsorption portion has a plurality of adsorption portions for adsorbing and removing impurities contained in the crude ammonia by the adsorbent,
Wherein the plurality of adsorption units are installed in parallel,
Wherein the plurality of adsorption units are fed with crude ammonia derived from the storage unit in a separated state. The method of claim 3,
Wherein the adsorption portion has a plurality of adsorption portions for adsorbing and removing impurities contained in the crude ammonia by the adsorbent,
Wherein the plurality of adsorption units are installed in parallel,
Wherein the plurality of adsorption units are fed with crude ammonia derived from the storage unit in a separated state. 3. The method according to claim 1 or 2,
Wherein the analyzer comprises a gas chromatograph analyzer and a cavity ring down spectrometer,
The ammonia removed from the adsorption unit is analyzed for methane concentration by the gas chromatograph analyzer and the concentration of water is analyzed by the cavity ring down spectrometer. The method of claim 3,
Wherein the analyzer comprises a gas chromatograph analyzer and a cavity ring down spectrometer,
The ammonia removed from the adsorption unit is analyzed for methane concentration by the gas chromatograph analyzer and the concentration of water is analyzed by the cavity ring down spectrometer. 5. The method of claim 4,
Wherein the analyzer comprises a gas chromatograph analyzer and a cavity ring down spectrometer,
The ammonia removed from the adsorption unit is analyzed for methane concentration by the gas chromatograph analyzer and the concentration of water is analyzed by the cavity ring down spectrometer. 6. The method of claim 5,
Wherein the analyzer comprises a gas chromatograph analyzer and a cavity ring down spectrometer,
The ammonia removed from the adsorption unit is analyzed for methane concentration by the gas chromatograph analyzer and the concentration of water is analyzed by the cavity ring down spectrometer. 3. The method according to claim 1 or 2,
Wherein the adsorbent is at least one inorganic porous adsorbent selected from synthetic zeolite and activated carbon. The method of claim 3,
Wherein the adsorbent is at least one inorganic porous adsorbent selected from synthetic zeolite and activated carbon. 5. The method of claim 4,
Wherein the adsorbent is at least one inorganic porous adsorbent selected from synthetic zeolite and activated carbon. 6. The method of claim 5,
Wherein the adsorbent is at least one inorganic porous adsorbent selected from synthetic zeolite and activated carbon. The method according to claim 6,
Wherein the adsorbent is at least one inorganic porous adsorbent selected from synthetic zeolite and activated carbon. 8. The method of claim 7,
Wherein the adsorbent is at least one inorganic porous adsorbent selected from synthetic zeolite and activated carbon. 9. The method of claim 8,
Wherein the adsorbent is at least one inorganic porous adsorbent selected from synthetic zeolite and activated carbon. 10. The method of claim 9,
Wherein the adsorbent is at least one inorganic porous adsorbent selected from synthetic zeolite and activated carbon.

Images