Precipitate removal system and precipitate removal method

Abstract

This invention provides a precipitate removal system that prevents blockage of ammonia gas piping due to precipitates and reduces the risk of emergency shutdowns caused by pressure increases in the distillation column. [Solution] The precipitate removal system comprises an ammonia gas pipe through which ammonia gas flows, communicating with an ammonia gas outlet located at the top of a distillation column for recovering ammonia from ammonia water, and a collection unit provided on the ammonia gas pipe for collecting precipitates deposited from ammonia gas. The ammonia gas pipe includes a supply port for water vapor or a thermal fluid containing water and an outlet for a thermal fluid, provided so as to sandwich at least a portion of the collection unit in the direction of ammonia gas flow within the ammonia gas pipe.

Description

Technical Field

[0001] The present disclosure relates to a deposit removal system and a deposit removal method for removing deposits deposited in a pipe.

Background Art

[0002] Conventionally, as a method for recovering ammonia from aqueous ammonia, a method of distilling aqueous ammonia in a distillation column to obtain high-concentration ammonia gas is known. For example, Patent Document 1 describes a fabric processing system (fabric processing apparatus) that modifies a fabric using liquid ammonia. In the fabric processing system, low-concentration ammonia gas evaporated in the process of fabric modification is recovered as aqueous ammonia, and the aqueous ammonia is distilled in a distillation column, and the obtained high-concentration ammonia gas is liquefied and used again for fabric modification.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The inventors have found that deposits derived from ammonia gas accumulate in the pipe through which high-concentration ammonia gas discharged from the top of the distillation column flows, and a pressure increase in the distillation column due to blockage of the pipe by the deposits may occur. An increase in the pressure inside the distillation column may cause a distillation column emergency stop (trip).

[0005] In view of the above circumstances, at least some embodiments of the present invention aim to provide a deposit removal system that can prevent blockage of the ammonia gas pipe by deposits and reduce the risk of an emergency stop associated with an increase in the pressure inside the distillation column.

Means for Solving the Problems

[0006] A precipitate removal system according to at least some embodiments of the present invention is A distillation column for recovering ammonia from aqueous ammonia is connected to an ammonia gas outlet located at the top of the column, and an ammonia gas piping through which the ammonia gas flows is connected. A collection unit is provided on the ammonia gas piping for collecting precipitates that precipitate from the ammonia gas, Equipped with, The ammonia gas piping includes a supply port for water vapor or a thermal fluid containing water and an outlet for the thermal fluid, which are provided so as to sandwich at least a part of the collection section in the flow direction of the ammonia gas within the ammonia gas piping.

[0007] Furthermore, the precipitate removal method according to at least some embodiments of the present invention is A method for removing precipitates in an ammonia gas pipe through which ammonia gas flows, which is connected to the outlet of ammonia gas located at the top of a distillation column for recovering ammonia from aqueous ammonia, The steps include stopping the operation of the distillation column, The steps include supplying water vapor or a thermal fluid containing water to a collection unit provided on the ammonia gas piping, It is equipped with. [Effects of the Invention]

[0008] According to at least some embodiments of the present invention, since a collection unit is provided on the ammonia gas piping, precipitates originating from ammonia gas can be concentrated in the collection unit within the ammonia gas piping. Furthermore, since the thermal fluid supply and discharge ports are provided so as to sandwich at least a portion of the collection section in the direction of ammonia gas flow, efficient removal of precipitates becomes possible by guiding the thermal fluid into the ammonia gas piping so as to pass through the collection section where precipitates are unevenly distributed. Therefore, it is possible to prevent blockage of ammonia gas piping due to precipitates and reduce the risk of emergency shutdowns due to pressure increases in the distillation column. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic diagram of a precipitate removal system according to one embodiment. [Figure 2] This is a cross-sectional view of a piping unit according to one embodiment. [Figure 3A] This is a view of a piping unit according to one embodiment, as seen through the line AA in Figure 2. [Figure 3B] This is a view of a piping unit according to another embodiment, as seen from arrow AA in Figure 2. [Figure 4A] This is a view of a piping unit according to one embodiment, as seen through the arrow BB in Figure 2. [Figure 4B] This is a view of a piping unit according to another embodiment, as seen from arrow BB in Figure 2. [Figure 5] This is a schematic diagram of a fabric processing system according to one embodiment. [Figure 6] This is a schematic diagram of a first ammonia treatment apparatus according to one embodiment. [Figure 7] This is a flowchart showing the flow of a precipitate removal method according to one embodiment. [Modes for carrying out the invention]

[0010] One embodiment of the present invention will be described below with reference to the attached drawings. However, the dimensions, materials, shapes, relative arrangements, etc., of the components described as embodiments or shown in the drawings are not intended to limit the scope of the present invention, but are merely illustrative examples.

[0011] Figure 1 is a schematic diagram of a precipitate removal system according to one embodiment. The precipitate removal system 10 shown in Figure 1 is installed in the flow path of ammonia gas AG flowing out of the distillation equipment 110 for the purpose of removing precipitates PM that precipitate from ammonia gas AG. The distillation equipment 110 will be described below, followed by a description of the configuration of the precipitate removal system 10.

[0012] In some embodiments, as shown in FIG. 1, the distillation facility 110 includes a distillation column 111, a reboiler 120 for heating a part of the aqueous ammonia taken out from the distillation column 111, and a condenser 130 for condensing the water vapor contained in the ammonia gas exited from the distillation column 111. In other embodiments, the distillation facility 110 does not include the condenser 130 and includes only the distillation column 111 and the reboiler 120.

[0013] As shown in FIG. 1, the distillation column 111 includes a top portion 112 provided with an outlet 116 for ammonia gas AG and a bottom portion 114 provided with an outlet 119 for aqueous ammonia AW2. The aqueous ammonia AW1 to be processed by the distillation column 111 flows into the internal space of the distillation column 111 from an inlet 118 provided at a height position between the top portion 112 and the bottom portion 114. In the internal space of the distillation column 111, the ammonia gas AG separated from the aqueous ammonia AW1 flows out from the outlet 116 of the top portion 112. On the other hand, low-concentration aqueous ammonia AW2 accumulates at the bottom portion 114 and is discharged from the outlet 119 of the bottom portion 114.

[0014] In the flow direction of the ammonia gas AG, a condenser 130 is provided on the downstream side of the distillation column 111. Specifically, the condenser 130 is provided on an outlet pipe 140 connected to the outlet 116 of the top portion 112 of the distillation column 111. The condenser 130 cools the ammonia gas AG exited from the outlet 116 of the top portion 112 by heat exchange with a refrigerant CM to condense the water vapor contained in the ammonia gas AG, and returns the condensate containing a large amount of moisture to the internal space of the distillation column 111 as a reflux liquid R through a reflux line 142. The ammonia gas AG after passing through the condenser 130 flows downstream toward the precipitate removal system 10.

[0015] As shown in FIG. 1, the reboiler 120 is configured to heat the aqueous ammonia AW2 accumulated at the bottom portion 114 and return it to the internal space of the distillation column 111 as a vapor flow or a gas-liquid two-phase flow. The reboiler 120 is connected to the bottom of the column 114 via ammonia water piping 122 and the reboiler outlet pipe 124. The ammonia water AW2 accumulated at the bottom of the column 114 is sent to the reboiler 120 via the ammonia water piping 122. The ammonia water AW2 heated in the reboiler 120 is returned to the column space of the distillation column 111 via the reboiler outlet pipe 124 as a low-concentration ammonia flow AF, which is either a steam flow or a gas-liquid bilayer flow.

[0016] The distillation apparatus 110 with the above configuration recovers high-concentration ammonia gas AG from aqueous ammonia AW1. The high-concentration ammonia gas AG exiting from the top 112 of the distillation column 111 is led to the precipitate removal system 10.

[0017] In some embodiments, as shown in Figure 1, the precipitate removal system 10 includes an ammonia gas pipe 20 through which ammonia gas AG flows, and a collection unit 30 provided on the ammonia gas pipe 20.

[0018] The ammonia gas piping 20 is connected to the ammonia gas AG outlet 116 located at the top 112 of the distillation column 111. In the exemplary embodiment shown in Figure 1, the ammonia gas piping 20 communicates with the ammonia gas AG outlet 116 of the distillation column 111 via an outlet piping 140 connected to the ammonia gas AG outlet 116 of the distillation column 111. The ammonia gas AG outlet piping 140 on the distillation column 111 side has an upstream end connected to the ammonia gas AG outlet 116 in the distillation column 111 and a downstream end connected to the ammonia gas piping 20 at connection point P. The connection between the outlet piping 140 and the ammonia gas piping 20 at connection point P may be made via a flange (not shown). In another embodiment, the ammonia gas piping 20 also functions as the outlet piping 140 to which the condenser 130 of the distillation equipment 110 is provided. That is, the ammonia gas piping 20 communicates with the ammonia gas AG outlet 116 of the distillation column 111 by being directly connected to the ammonia gas AG outlet 116 of the distillation column 111.

[0019] As shown in Figure 1, the ammonia gas piping 20 includes an upstream ammonia gas piping 20A and a downstream ammonia gas piping 20B located downstream of the upstream ammonia gas piping 20A in the flow direction of the ammonia gas AG.

[0020] As shown in Figure 1, the ammonia gas piping 20 in the above configuration is provided with a collection unit 30 for collecting precipitates PM that precipitate from the high-concentration ammonia gas AG flowing through the ammonia gas piping 20. In the embodiment shown in Figure 1, the inlet of the ammonia gas AG in the collection unit 30 is connected to the upstream ammonia gas piping 20A, and the outlet of the ammonia gas AG in the collection unit 30 is connected to the downstream ammonia gas piping 20B.

[0021] During the natural cooling process of ammonia gas (AG), atmospheric components and water contained in the ammonia gas (AG) combine with the ammonia to form precipitates (PM). According to the inventors' findings, these precipitates (PM) tend to accumulate in areas of the ammonia gas piping (20) where pressure loss occurs. Furthermore, the inventors' diligent research has revealed that the precipitates (PM) from ammonia gas (AG) can be removed using steam, hot water, or a mixture thereof. The precipitates (PM) may also contain ammonium salts (such as ammonium carbonate, ammonium carbamate, and ammonium bicarbonate).

[0022] In some embodiments, as shown in Figure 1, the collection unit 30 has a labyrinth channel 31 for causing the flow of ammonia gas AG in the ammonia gas piping 20 to meander. In this case, the collection unit 30 causes a pressure loss in the labyrinth channel 31, promoting the precipitation of precipitates PM from ammonia gas AG. In other embodiments not shown, the collection unit 30 may be a check valve that causes pressure loss. In this case, the check valve (collection unit 30) promotes the precipitation of ammonia gas (AG) precipitates (PM).

[0023] Thus, the collection unit 30 is an element that causes pressure loss in relation to the flow of ammonia gas AG, based on the inventors' knowledge that precipitates PM from ammonia gas AG tend to accumulate in the ammonia gas piping 20 at locations where pressure loss occurs. Therefore, the precipitate PM derived from ammonia gas AG is concentrated in areas where pressure loss occurs within the ammonia gas piping 20 (collection section 30).

[0024] Therefore, in some embodiments, the ammonia gas piping 20 includes a supply port 21 and an outlet port 22 for a thermal fluid F containing steam or water, in order to enable the cleaning of precipitates PM accumulated in the collection section 30 with a thermal fluid F. For example, the thermal fluid F may be steam, hot water, or a mixture thereof.

[0025] The supply port 21 and the discharge port 22 are provided so as to sandwich at least a portion of the collection unit 30 in the flow direction of the ammonia gas AG. In one embodiment, as shown in Figure 1, the supply port 21 and the discharge port 22 of the ammonia gas piping 20 are provided at a first position P1 and a second position P2, respectively, which are located on both sides of the collection unit 30 in the flow direction of the ammonia gas AG. In the exemplary embodiment shown in Figure 1, the first position P1 is located upstream of the second position P2 in the flow direction of ammonia gas AG, the supply port 21 is provided in the upstream ammonia gas piping 20A, and the discharge port 22 is provided in the downstream ammonia gas piping 20B. In other embodiments not shown, the first position P1 may be located downstream of the second position P2 in the flow direction of ammonia gas AG, the supply port 21 may be provided in the downstream ammonia gas piping 20B, and the discharge port 22 may be provided in the upstream ammonia gas piping 20A. Here, the flow direction of ammonia gas AG is the direction along the pipe axis of the ammonia gas piping 20, as shown in Figure 1.

[0026] When cleaning the collection unit 30 with steam or a thermal fluid F containing water, the thermal fluid F flows into the collection unit 30 from the supply port 21 at the first position P1 via the ammonia gas pipe 20, and is discharged from the discharge port 22 at the second position P2 together with the precipitate PM that is unevenly distributed in the collection unit 30. The precipitate PM containing ammonium salts is discharged from the outlet 22 along with the thermal fluid F by thermal decomposition upon contact with the thermal fluid F, or by dissolution in the water contained in the thermal fluid F.

[0027] In the embodiment shown in Figure 1, the precipitate removal system 10 includes a supply line 13 for thermal fluid F connected to a supply port 21 and a discharge line 14 for thermal fluid F connected to a discharge port 22. The upstream end of the supply line 13 is connected to a thermal fluid source H that generates the thermal fluid F. The supply line 13 and the discharge line 14 may be composed of permanent piping or of temporary piping including flexible tubing. In the exemplary embodiment shown in Figure 1, the precipitate removal system 10 includes a thermal fluid supply valve 15 provided in the supply line 13 and a thermal fluid discharge valve 16 provided in the discharge line 14. The thermal fluid supply valve 15 and the thermal fluid discharge valve 16 are opened when washing precipitates PM that are unevenly distributed in the collection section 30 using thermal fluid F, and are closed at all other times.

[0028] Incidentally, it is desirable to perform the cleaning of the collection section 30 with the thermal fluid F while shutting off the flow of ammonia gas AG from the distillation equipment 110. Therefore, in some embodiments, the precipitate removal system 10 includes a first on-off valve 11 and a second on-off valve 12 provided on both sides of the collection section 30, the thermal fluid F supply port 21 and the discharge port 22 in the flow direction of ammonia gas AG. The first on-off valve 11 and the second on-off valve 12 are closed when cleaning precipitates PM that are unevenly distributed in the collection section 30 using the thermal fluid F, and are open at all other times.

[0029] In the embodiment shown in Figure 1, the first on-off valve 11 is located upstream of the supply port 21 in the flow direction of ammonia gas AG. That is, the first on-off valve 11 is located on the upstream ammonia gas piping 20A. The first on-off valve 11 may also be a pressure regulating valve for adjusting the pressure inside the distillation column 111. The second on-off valve 12 is located downstream of the outlet 22 in the flow direction of ammonia gas AG. That is, the second on-off valve 12 is located on the downstream ammonia gas piping 20B.

[0030] Next, a specific embodiment of the collection unit 30 will be described. However, the collection unit 30 is not limited to the embodiments shown below.

[0031] Figure 2 is a cross-sectional view of a piping unit according to one embodiment. Although arrows indicating the flow of ammonia gas AG and thermal fluid F are shown in Figure 2, ammonia gas AG and thermal fluid F are not supplied to the piping unit 40 simultaneously. Figure 3A is a view of a piping unit according to one embodiment, taken along the arrow AA in Figure 2. Figure 3B is a view of a piping unit according to another embodiment, taken along the arrow AA in Figure 2. Figure 4A is a view of a piping unit according to one embodiment, taken along the arrow BB in Figure 2. Figure 4B is a view of a piping unit according to another embodiment, taken along the arrow BB in Figure 2. As shown in Figures 3A to 4B, the vertical direction is defined as the up-down direction of the paper, and the horizontal direction is defined as the left-right direction of the paper.

[0032] In some embodiments, as shown in Figure 2, the precipitate removal system 10 includes a piping unit 40 that integrates a collection unit 30, a supply port 21, and a discharge port 22. The piping unit 40 includes a piping element 50 and a thermal fluid supply port 41 and a thermal fluid discharge port 42 that form the supply port 21 and the discharge port 22, respectively.

[0033] The piping element 50 constitutes at least a portion of the ammonia gas piping 20. The piping element 50 has flanges 58 (58A, 58B) on both sides. In the embodiment shown in Figure 2, the piping element 50 has a linearly extending cylindrical shape. The piping element 50 includes one end 56 to which a flange 58A is provided and the other end 57 to which a flange 58B is provided.

[0034] In the exemplary embodiment shown in Figure 2, flange 58A is connected to the upstream ammonia gas pipe 20A, and flange 58B is connected to the downstream ammonia gas pipe 20B. In this case, ammonia gas AG flowing into the piping unit 40 from flange 58A flows through the piping element 50 toward flange 58B. In other embodiments not shown, flange 58A may be connected to the downstream ammonia gas piping 20B, and flange 58B may be connected to the upstream ammonia gas piping 20A.

[0035] In some embodiments, as shown in Figure 2, the piping element 50 is provided with a collection section 30 located between the heat fluid supply port 41 and the heat fluid discharge port 42.

[0036] In one embodiment, a labyrinth channel 31, which functions as a collection section 30, is formed within the piping element 50. In this case, as illustrated in Figure 2, the piping element 50 may include a straight pipe section 51, an expanded pipe section 52, a large-diameter straight pipe section 53, an expanded pipe section 54, and a straight pipe section 55, from the viewpoint of securing space for the labyrinth flow path 31 (collection section 30). The labyrinth flow path 31 is provided within the large-diameter straight pipe section 53 of the piping element 50. By forming expanded pipe sections 52 and 54 on both sides of the large-diameter straight pipe section 53, the inner diameter of the large-diameter straight pipe section 53 is larger than that of the straight pipe sections 51 and 55.

[0037] The thermal fluid supply port 41 is provided on one end 56 of the flange 58A side of the piping element 50 and forms the supply port 21 for the thermal fluid F. In the exemplary embodiment shown in Figure 2, the thermal fluid supply port 41 is provided projecting radially outward from the outer circumferential surface of the straight pipe portion 51 that forms one end 56 of the piping element 50. The thermal fluid supply port 41 may also be cylindrical in shape. As shown in Figure 2, the thermal fluid supply port 41 may have a flange 41A for connecting to the thermal fluid supply line 13.

[0038] The thermal fluid discharge port 42 is provided on the other end 57 side of the flange 58B side of the piping element 50, and forms the outlet 22 for the thermal fluid F. The thermal fluid discharge port 42 is provided on the piping element 50 on the opposite side of the collection section 30 from the thermal fluid supply port 41. In the exemplary embodiment shown in Figure 2, the thermal fluid discharge port 42 is provided in the straight pipe section 55 that forms the other end 57 of the piping element 50, projecting radially outward from the outer circumferential surface of the straight pipe section 55. The thermal fluid discharge port 42 may also be cylindrical in shape.

[0039] As described above, the piping element 50 is provided with a collection section 30 between the heat fluid supply port 41 and the heat fluid discharge port 42.

[0040] The collection section 30 includes baffle plates 32 that form a labyrinth channel 31. In the exemplary embodiment shown in Figure 2, the baffle plate 32 includes a first baffle plate 34, a second baffle plate 36, and a third baffle plate 38. The baffle plates 32, each projecting from the inner wall surface 53W of the large-diameter straight pipe section 53 in a direction intersecting the flow direction of ammonia gas AG, are spaced apart from each other in the flow direction of ammonia gas AG. The first baffle plate 34 and the second baffle plate 36 each protrude in opposite directions relative to the central axis O of the large-diameter straight pipe section 53. That is, the second baffle plate 36 protrudes from the inner wall surface 53W opposite to the first baffle plate 34 relative to the central axis O of the large-diameter straight pipe section 53. Similarly, the second baffle plate 36 and the third baffle plate 38 protrude in opposite directions relative to the central axis O of the large-diameter straight pipe section 53. That is, the third baffle plate 38 protrudes from the inner wall surface 53W opposite to the second baffle plate 36 relative to the central axis O of the large-diameter straight pipe section 53.

[0041] As shown in Figures 3A to 4B, the baffle plate 32 includes a side end surface 33 that does not come into contact with the inner wall surface 53W of the large-diameter straight pipe section 53. The gap S through which the ammonia gas AG and thermal fluid F flow is defined by the side end surface 33 of the baffle plate 32 and the inner wall surface 53W of the large-diameter straight pipe section 53. The portion of the inner wall surface 53W that defines the gap S includes the lower end 53B of the inner wall surface 53W. Therefore, when cleaning the collection section 30 with steam or a thermal fluid F containing water, the liquid component of the thermal fluid F can pass through the gap S, preventing the residue of the liquid component of the thermal fluid F in the large-diameter straight pipe section 53.

[0042] As shown in Figures 3A to 4B, the baffle plate 32 blocks more than half of the cross-sectional area of ​​the large-diameter straight pipe section 53, from the viewpoint of increasing pressure loss with respect to the flow of ammonia gas AG. In the exemplary embodiment shown in Figure 3A, the length of the portion of the contour of the first baffle plate 34A(34) that contacts the inner wall surface 53W of the large-diameter straight pipe section 53 is longer than half the length of the inner circumference of the large-diameter straight pipe section 53. The upper end 35T of the side end face 35 of the first baffle plate 34A(34) is located at a height vertically lower than the upper end 53T of the inner wall surface 53W, and the side end face 35 extends vertically downward from the upper end 35T. The side end face 35 changes direction of extension at the same height as the central axis O and extends linearly to the lower end 35B. The lower end 35B of the side end face 35 coincides with the lower end 53B of the inner wall surface 53W. In the embodiment shown in Figure 3B, the length of the portion of the contour of the first baffle plate 34B(34) that is in contact with the inner wall surface 53W of the large-diameter straight pipe section 53 is equal to half the length of the inner circumference of the large-diameter straight pipe section 53. The upper end 35T of the side end face 35 of the first baffle plate 34B(34) is located at a height vertically lower than the upper end 53T of the inner wall surface 53W, and the lower end 35B of the side end face 35 is located at a height vertically higher than the lower end 53B of the inner wall surface 53W. The side end face 35 extends linearly from the upper end 35T to the lower end 35B, passing through the central axis O.

[0043] If the first baffle plate 34 is the embodiment shown in Figure 3A, then the second baffle plate 36 is the second baffle plate 36A(36) shown in Figure 4A. The second baffle plate 36A(36) is mirror-image symmetric to the first baffle plate 34A(34) shown in Figure 3A, and has the same configuration as the first baffle plate 34A(34). On the other hand, if the first baffle plate 34 is the embodiment shown in Figure 3B, then the second baffle plate 36 is the second baffle plate 36B(36) shown in Figure 4B. The second baffle plate 36B(36) is mirror-image symmetric to the first baffle plate 34B(34) shown in Figure 3B, and has the same configuration as the first baffle plate 34B(34).

[0044] Furthermore, if the first baffle plate 34 and the second baffle plate 36 are embodiments shown in Figures 3A and 4A, the third baffle plate 38 has the same configuration as the first baffle plate 34A(34) shown in Figure 3A. On the other hand, if the first baffle plate 34 and the second baffle plate 36 are embodiments shown in Figures 3B and 4B, the third baffle plate 38 has the same configuration as the first baffle plate 34B(34) shown in Figure 3B.

[0045] By installing the precipitate removal system 10 with the above configuration in the flow path of ammonia gas (AG) flowing out from the distillation equipment 110, precipitates (PM) that precipitate from ammonia gas (AG) can be removed.

[0046] From here, we will describe a fabric processing system 1 and the first ammonia treatment apparatus 100 located within the fabric processing system 1 as specific examples of applications for the precipitate removal system 10. However, the applications of the precipitate removal system 10 are not limited to the fabric processing system 1 and the first ammonia treatment apparatus 100 described below.

[0047] Figure 5 is a schematic diagram of a fabric processing system according to one embodiment. Figure 6 is a schematic diagram of a first ammonia processing device according to one embodiment. As shown in Figure 6, the precipitate removal system 10 is used in conjunction with the distillation column 111 of the first ammonia treatment apparatus 100.

[0048] First, with reference to Figure 5, several embodiments of the fabric processing system 1 will be described. Fabric processing system 1 is a device for modifying a fabric to be processed C using liquid ammonia L. By immersing the fabric to be processed C in liquid ammonia L, the fiber structure changes, which can improve the properties of the fabric to be processed C, such as tensile strength, softness of touch, shrinkage resistance, and wrinkle resistance.

[0049] In some embodiments, as shown in Figure 5, the fabric processing system 1 includes a processing tank 2 for impregnating a fabric to be processed C with liquid ammonia L, and a heating device 3 for volatilizing ammonia from the fabric to be processed C impregnated with liquid ammonia L. The fabric processing system 1 further includes a processing chamber 4 housing the processing tank 2 and the heating device 3, and a volatilization chamber 5 provided adjacent to the processing chamber 4.

[0050] The fabric to be processed C is continuously fed into the processing chamber 4 and immersed in the liquid ammonia L stored in the processing tank 2. After passing through the processing tank 2, the fabric to be processed C is heated by the heating device 3, at which point most of the liquid ammonia L impregnated in the fabric to be processed C volatilizes. The fabric C, after passing through the heating device 3, is sent to the volatilization chamber 5, where it is sprayed with high-temperature steam before being discharged from the volatilization chamber 5. Any liquid ammonia L remaining on the fabric C is blown away and volatilized along with the steam in the volatilization chamber 5.

[0051] Furthermore, the internal pressure of the processing chamber 4 and the volatilization chamber 5 may be adjusted to be slightly negative compared to atmospheric pressure. This prevents leakage of ammonia gas volatilized from liquid ammonia L in the processing chamber 4 and the volatilization chamber 5.

[0052] The fabric processing system 1 may include seal boxes 6(6A, 6B) provided at the entrances and exits of the fabric to be processed C in the processing chamber 4 and the volatilization chamber 5 to prevent leakage of ammonia gas from the processing chamber 4 and the volatilization chamber 5. Additionally, a seal box 6(6C) may be provided between the processing chamber 4 and the volatilization chamber 5 to prevent the movement of ammonia gas between the two chambers.

[0053] In some embodiments, the fabric processing system 1 includes a first ammonia processing device 100 and a second ammonia processing device 200 for recovering ammonia from ammonia gas. The ammonia gas generated during the modification of the fabric C to be processed is treated by the first ammonia processing device 100 and the second ammonia processing device 200 and supplied back to the processing tank 2 as liquid ammonia L.

[0054] In the embodiment shown in Figure 5, the fabric processing system 1 includes an ammonia gas pipe 7A connecting the volatilization chamber 5 and the first ammonia processing device 100. The first ammonia processing device 100 generates a high-concentration ammonia gas (recovered ammonia gas G3) from the ammonia gas G1 in the volatilization chamber 5. Details of the processing in the first ammonia processing device 100 will be described later.

[0055] The fabric processing system 1 may also include an ammonia gas piping 7B connecting the seal box 6 and the first ammonia processing device 100. The first ammonia processing device 100 may generate recovered ammonia gas G3 from the seal gas G2 drawn into the seal box 6.

[0056] In the embodiment shown in Figure 5, the fabric processing system 1 includes an ammonia gas pipe 7C connecting the first ammonia processing device 100 and the second ammonia processing device 200, and a liquid ammonia pipe 8 connecting the second ammonia processing device 200 and the processing chamber 4. The second ammonia processing device 200 liquefies the recovered ammonia gas G3 supplied from the first ammonia processing device 100 and supplies the liquid ammonia L generated from the recovered ammonia gas G3 to the processing tank 2.

[0057] The fabric processing system 1 may also include ammonia gas piping 7D connecting the processing chamber 4 and the second ammonia processing device 200. The second ammonia processing device 200 may be configured to liquefy the ammonia gas G4 in the processing chamber 4 to produce liquid ammonia L.

[0058] The ammonia gas G1 in the volatilization chamber 5 is formed when liquid ammonia L remaining on the processed fabric C volatilizes along with water vapor, and contains a large amount of water vapor. On the other hand, the ammonia gas G4 in the processing chamber 4 is a mixture of ammonia gas evaporated from the processing tank 2 and ammonia gas volatilized from the workpiece fabric C by heating in the heating device 3, and has a higher ammonia concentration than the ammonia gas G1. As described above, by processing two types of gases with different ammonia concentrations (ammonia gas G1 and ammonia gas G4) through separate pathways, the liquefaction efficiency of ammonia gas in the entire fabric processing system 1 is improved.

[0059] The fabric processing system 1 may also include a detoxification device 300 for detoxifying ammonia gas and ammonia gas piping 7E for sending the ammonia gas G5 to be detoxified from the first ammonia treatment device 100 to the detoxification device 300.

[0060] Next, the first ammonia treatment apparatus 100 will be described with reference to Figure 6. In some embodiments, the first ammonia treatment apparatus 100 is a device for recovering ammonia from ammonia water that has absorbed ammonia gas. The first ammonia treatment apparatus 100 includes an absorption tower 150 for absorbing ammonia gas into ammonia water, a distillation tower 111 for recovering ammonia from ammonia water, and ammonia water piping 180 through which ammonia water flows between the absorption tower 150 and the distillation tower 111. Furthermore, the ammonia water piping 180 may include the first ammonia water piping 180A, the second ammonia water piping 180B, the third ammonia water piping 180C, the fourth ammonia water piping 180D, and the fifth ammonia water piping 180E, which constitute a part of the ammonia water piping 180.

[0061] Ammonia gas G1 is supplied to the absorption tower 150 via ammonia gas piping 7A. The ammonia water AW1 that has absorbed ammonia gas G1 in the absorption tower 150 is sent to the distillation tower 111 via ammonia water piping 180 (180A, 180B). Furthermore, aqueous ammonia AW1 may absorb the seal gas G2 supplied to the absorption tower 150 via the ammonia gas piping 7B. Furthermore, any ammonia gas that was not absorbed by the ammonia water AW1 may be discharged outside the absorption tower 150 as ammonia gas G5 via the ammonia gas piping 7E.

[0062] The distillation column 111 shown in Figure 6 has the same configuration as the distillation column 111 shown in Figure 1. The ammonia gas AG, separated from the ammonia water AW1 in the space inside the distillation column 111, flows out of the distillation column 111 via the outlet pipe 140 and flows through the ammonia gas pipe 20 connected to the outlet pipe 140 at connection point P. The ammonia gas AG that has passed through the precipitate removal system 10 is sent to the second ammonia treatment device 200 as recovered ammonia gas G3.

[0063] As mentioned above, the precipitate PM from ammonia gas AG originates from atmospheric components contained in ammonia gas AG. These atmospheric components are collected in the first ammonia treatment device 100 along with ammonia gas G1 from a small amount of air that flows into the volatilization chamber 5, and then transported to the distillation column 111.

[0064] In some embodiments, the first ammonia treatment apparatus 100 includes a reboiler 120 and a condenser 130. The configurations of the reboiler 120 and the condenser 130 are as described above.

[0065] In some embodiments, the first ammonia treatment apparatus 100 includes a preheater 170 for heating aqueous ammonia AW1 upstream of the distillation column 111. The preheater 170 is a heat exchanger for exchanging heat between aqueous ammonia AW1 from the absorption column 150 and high-temperature aqueous ammonia AW2 from the distillation column 111.

[0066] The first ammonia treatment apparatus 100 may also include a first ammonia water tank 160 for storing ammonia water AW1 from the absorption tower 150 and a second ammonia water tank 190 for storing ammonia water AW2 from the distillation tower 111. The first ammonia water tank 160 may supply ammonia water AW1 to the distillation column 111 via ammonia water piping 180 (180B). The first ammonia water tank 160 may be located upstream of the preheater 170. The second ammonia water tank 190 may supply ammonia water AW2 to the absorption tower 150 via ammonia water piping 180 (180E). In this case, the ammonia water AW2 supplied to the absorption tower 150 merges with the ammonia water AW1 circulating within the absorption tower 150.

[0067] Next, we will explain the precipitate removal method in the precipitate removal system 10. Figure 7 is a flowchart showing the flow of a precipitate removal method according to one embodiment.

[0068] As shown in Figure 7, prior to the removal of precipitates, the operation of the distillation column 111 is stopped (S10). In step S10, distillation in the distillation column 111 is stopped, and the supply of aqueous ammonia AW1 to the distillation column 111 is stopped.

[0069] After step S10, the first on-off valve 11 and the second on-off valve 12 are closed (S12). In one embodiment, the first on-off valve 11 and the second on-off valve 12 are closed automatically in response to a control signal transmitted from a control device (not shown). In this case, the first on-off valve 11 and the second on-off valve 12 may be automatically closed in response to a control signal generated after a predetermined time has elapsed since the distillation column 111 stopped operating. Alternatively, the first on-off valve 11 and the second on-off valve 12 may be closed by manual operation by an operator.

[0070] After step S12, water vapor or a thermal fluid F containing water is supplied to the collection unit 30 (S14). At this time, with the heat fluid supply valve 15 and the heat fluid discharge valve 16 open, the heat fluid F is supplied to the collection unit 30.

[0071] The characteristic configurations of the precipitate removal system and precipitate removal method according to some of the embodiments described above are summarized as follows.

[0072] [1] A precipitate removal system (10) according to at least some embodiments of the present invention is An ammonia gas piping (20) is connected to an ammonia gas (AG) outlet (116) located at the top (112) of a distillation column (111) for recovering ammonia from aqueous ammonia (AW1), and through which ammonia gas (AG) flows. A collection unit (30) is installed on the ammonia gas piping (20) to collect precipitates (PM) that precipitate from ammonia gas (AG), Equipped with, The ammonia gas piping (20) includes a supply port (21) for water vapor or a heat fluid (F) containing water, and an outlet (22) for the heat fluid (F), which are provided so as to sandwich at least a portion of the collection section (30) in the direction of flow of ammonia gas (AG) within the ammonia gas piping (20).

[0073] According to the configuration described in [1] above, since the collection unit (30) is provided on the ammonia gas pipe (20), precipitates (PM) derived from ammonia gas (AG) can be concentrated in the collection unit (30) within the ammonia gas pipe (20). Furthermore, since the thermal fluid (F) supply port (21) and discharge port (22) are provided so as to sandwich at least a portion of the collection section (30) in the direction of ammonia gas (AG) flow, efficient removal of precipitates (PM) becomes possible by guiding the thermal fluid (F) to the ammonia gas piping (20) so as to pass through the collection section (30) where precipitates (PM) are unevenly distributed. Therefore, blockage of the ammonia gas piping (20) by precipitates (PM) can be prevented, and the risk of emergency shutdown due to pressure rise in the distillation column (111) can be reduced.

[0074] [2] In some embodiments, in the configuration of [1] above, The collection section (30) has a labyrinth channel (31) for causing the flow direction to meander.

[0075] Precipitates (PM) derived from ammonia gas (AG) tend to accumulate in ammonia gas piping (20) at locations where pressure loss occurs. According to the configuration described in [2] above, by providing a structure in the collection section (30) that generates a large pressure loss, such as a labyrinth channel (31), the precipitates (PM) can be made even more unevenly distributed in the collection section (30) within the ammonia gas piping (20).

[0076] [3] In some embodiments, in the configuration of [1] or [2] above, In the flow direction, the device is equipped with a first on-off valve (11) and a second on-off valve (12) located on either side of the collection section (30), the heat fluid (F) supply port (21), and the heat fluid (F) discharge port (22).

[0077] According to the configuration described in [3] above, by closing the first on-off valve (11) and the second on-off valve (12) before supplying the thermal fluid (F) to the collection unit (30), it is possible to prevent the discharge of ammonia gas (AG) from the thermal fluid (F) outlet (22).

[0078] [4] In some embodiments, in any of the configurations described in [1] to [3] above, A piping element (50) that constitutes at least a portion of the ammonia gas piping (20) and has flanges (58 (58A, 58B)) on both sides, A heat fluid supply port (41) is provided in the piping element (50) to form a heat fluid supply port (21) for heat fluid (F), A heat fluid discharge port (42) is provided on the opposite side of the heat fluid supply port (41) from the collection section (30) in the piping element (50), and forms a heat fluid (F) discharge port (22), It includes a piping unit (40) which includes the following.

[0079] According to the configuration described in [4] above, the precipitate removal system (10) can be realized by simple construction, which involves installing the piping unit (40) on the existing ammonia gas piping.

[0080] [5] A precipitate removal method according to at least some embodiments of the present invention is A method for removing precipitates (PM) in an ammonia gas pipe (20) through which ammonia gas (AG) flows, which is connected to an ammonia gas (AG) outlet (116) located at the top (112) of a distillation column (111) for recovering ammonia from aqueous ammonia (AW1), The step (S10) of stopping the operation of the distillation column (111), Step (S14) of supplying water vapor or a thermal fluid (F) containing water to a collection unit (30) installed on an ammonia gas pipe (20), It is equipped with.

[0081] According to the configuration described in [5] above, since the collection unit (30) is provided on the ammonia gas pipe (20), precipitates (PM) derived from ammonia gas (AG) can be concentrated in the collection unit (30) within the ammonia gas pipe (20). Furthermore, by supplying a thermal fluid (F) to the collection section (30) where precipitates (PM) are unevenly distributed, efficient removal of precipitates (PM) becomes possible. Therefore, it is possible to prevent blockage of the ammonia gas piping (20) due to the accumulation of precipitates (PM) and reduce the risk of emergency shutdown due to pressure rise in the distillation column (111).

[0082] [6] In some embodiments, in the configuration of [5] above, The ammonia gas piping (20) includes a thermal fluid (F) supply port (21) and a thermal fluid (F) discharge port (22) provided so as to sandwich at least a portion of the collection section (30) in the flow direction of the ammonia gas (AG) within the ammonia gas piping (20), Before supplying the thermal fluid (F) to the collection unit (30), the system includes a step (S12) of closing the first on-off valve (11) and the second on-off valve (12), which are provided on both sides of the collection unit (30), the thermal fluid (F) supply port (21), and the thermal fluid (F) discharge port (22) in the flow direction.

[0083] According to the configuration described in [6] above, by closing the first on-off valve (11) and the second on-off valve (12) before supplying the thermal fluid (F) to the collection unit (30), it is possible to prevent the discharge of ammonia gas (AG) from the thermal fluid (F) outlet (22).

[0084] In this specification, expressions describing relative or absolute arrangements such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial" shall not only describe such arrangements strictly, but also describe states of relative displacement with tolerances or angles or distances that allow for the same function to be achieved. For example, expressions such as "identical," "equal," and "homogeneous" that describe things being in an equal state not only describe a state of being strictly equal, but also describe a state in which there is a tolerance or a difference that is sufficient to achieve the same function. Furthermore, in this specification, expressions describing shapes such as quadrilaterals and cylindrical shapes shall not only represent geometrically precise quadrilaterals and cylindrical shapes, but also shapes that include uneven surfaces, chamfered surfaces, etc., to the extent that the same effect can be achieved. Furthermore, in this specification, expressions such as “equipped,” “possessed,” “possessed,” “included,” or “having” a component are not exclusive expressions that exclude the existence of other components. [Explanation of symbols]

[0085] 10: Precipitate removal system 11: First shut-off valve 12: Second shut-off valve 20: Ammonia gas piping 21: Supply port 22: Outlet 30: Collection section 31: Labyrinth channel 40: Piping Unit 41: Thermal fluid supply port 42: Thermal fluid discharge port 50: Piping elements 58 (58A, 58B): Flange 111: Distillation column 112: Tower top 116 :Exit AG: Ammonia gas F:thermal fluid

Claims

1. A distillation column for recovering ammonia from aqueous ammonia is connected to an ammonia gas outlet located at the top of the column, and an ammonia gas piping through which the ammonia gas flows is connected. A collection unit is provided on the ammonia gas piping for collecting precipitates that precipitate from the ammonia gas, Equipped with, The ammonia gas piping includes a supply port for water vapor or a thermal fluid containing water and an outlet for the thermal fluid, which are provided so as to sandwich at least a part of the collection section in the flow direction of the ammonia gas within the ammonia gas piping. Precipitate removal system.

2. The collection unit has a labyrinth channel for causing the ammonia gas flow to meander. The precipitate removal system according to claim 1.

3. In the flow direction, the collection section, the supply port for the thermal fluid, and the discharge port for the thermal fluid are provided on both sides of the collection section and the supply port for the thermal fluid, respectively, and the system includes a first on-off valve and a second on-off valve. A precipitate removal system according to claim 1 or 2.

4. A piping element comprising at least a portion of the ammonia gas piping, each having a flange on both sides, A heat fluid supply port is provided in the piping element, which forms the supply port for the heat fluid, A heat fluid discharge port is provided in the piping element, which forms the outlet for the heat fluid, Equipped with a piping unit including, The collection unit is provided in the piping element between the heat fluid supply port and the heat fluid discharge port. A precipitate removal system according to claim 1 or 2.

5. A method for removing precipitates in an ammonia gas pipe through which ammonia gas flows, which is connected to the outlet of ammonia gas located at the top of a distillation column for recovering ammonia from aqueous ammonia, The steps include stopping the operation of the distillation column, The steps include supplying water vapor or a thermal fluid containing water to a collection unit provided on the ammonia gas piping, Equipped with Precipitate removal method.

6. The ammonia gas piping includes a thermal fluid supply port and a thermal fluid discharge port, which are provided so as to sandwich at least a portion of the collection section in the flow direction of the ammonia gas within the ammonia gas piping. Before supplying the thermal fluid to the collection unit, the method includes closing a first on-off valve and a second on-off valve, which are provided on both sides of the collection unit, the thermal fluid supply port, and the thermal fluid discharge port in the flow direction. The method for removing precipitates according to claim 5.

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