Gas separation and recovery apparatus, gas separation and recovery method, and gas separation and recovery system

Abstract

To provide a gas separation recovery apparatus that can improve a recovery rate and a removal rate of a by-product, in separating and recovering required components from target gas including a plurality of components.SOLUTION: A gas separation recovery apparatus 1, which separates and recovers a required one component from target gas containing at least three components, comprises: a first gas separation device 2 having first adsorption towers 5A and 5B that separate the three components from the target gas, by a pressure fluctuation adsorption method; a second gas separation device 3 which is positioned at a secondary side of the first gas separation device 2, and has second adsorption towers 9A and 9B that separate the second component from the target gas by a pressure fluctuation adsorption method; and a gas passage 4 which is positioned between the first gas separation device 2 and the second gas separation device 3, and communicates the first adsorption towers with the second adsorption towers.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a gas separation and recovery apparatus, a gas separation and recovery method, and a gas separation and recovery system.

Background Art

[0002] In the oxo alcohol process (hereinafter sometimes referred to as the "oxo process" or simply the "process"), which is one of petrochemical plants, butyraldehyde is produced as an intermediate product from raw material propylene. The gas discharged from the process (hereinafter sometimes simply referred to as "exhaust gas") may contain useful components such as unreacted raw material components such as propylene and product components such as butyraldehyde. By recovering and reusing these useful components, the efficiency of the process can be increased.

[0003] In addition to useful components, the exhaust gas of the process mainly contains by-products such as propane, which is a side reaction product, and carbon dioxide, which is an inert component. In order to separate and recover useful components from the exhaust gas for reuse, it is necessary to reduce by-products. Also, in order to improve the efficiency of the process, it is necessary to increase the recovery rate of useful components and the removal rate of by-products.

[0004] By the way, as a method for separating and recovering an arbitrary component from a mixed gas, the PSA (Pressure Swing Adsorption) method and the TSA (Thermal Swing Adsorption) method are known. Also, a gas separation and recovery method combining PSA and TSA is used for the separation and purification of inorganic gases and hydrocarbons. Patent Document 1 discloses a method for recovering an arbitrary component from a gas containing multiple components by combining TSA and PSA.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] However, while the method disclosed in Patent Document 1 makes it possible to separate and recover the required components, there is a real need for the establishment of separation techniques that offer higher removal rates for by-products and higher recovery rates for useful components.

[0007] The present invention has been made in view of the above circumstances, and aims to provide a gas separation and recovery apparatus, a gas separation and recovery method, and a gas separation and recovery system that can improve the recovery rate and the removal rate of by-products when separating and recovering required components from a target gas containing multiple components. [Means for solving the problem]

[0008] To achieve the above objectives, the present invention employs the following configuration. [1] A gas separation and recovery apparatus for separating and recovering one required component from a target gas containing at least three components, A first gas separation apparatus having a first adsorption tower that separates a third component from the target gas by a pressure fluctuation adsorption method, A second gas separation apparatus is located on the secondary side of the first gas separation apparatus and has a second adsorption tower that separates the second component and the first component from the target gas by a pressure fluctuation adsorption method. A gas separation and recovery apparatus comprising a gas path located between the first gas separation apparatus and the second gas separation apparatus, and connecting the first adsorption tower and the second adsorption tower. [2] The gas separation and recovery apparatus according to [1], wherein the gas path is used to connect the first adsorption tower (after adsorption and before regeneration) and the second adsorption tower (after regeneration and before adsorption) for pressure equalization. [3] The gas separation and recovery apparatus according to [1] or [2], further comprising a third gas separation apparatus located on the primary side of the first gas separation apparatus, which removes a fourth component other than the first to third components from the target gas by a temperature fluctuation adsorption method. [4] The gas separation and recovery apparatus according to [3], wherein the target gas comprises one or more selected from the group consisting of butyraldehyde, carbon dioxide, propane, and propylene. [5] A gas separation and recovery method for separating and recovering one required component from a target gas containing at least three components, A third component is separated from the target gas by a first gas separation device using a pressure fluctuation adsorption method. A second gas separation device using a pressure fluctuation adsorption method separates the second component and the first component from the target gas, A gas separation and recovery method comprising connecting a first adsorption tower of the first gas separation device and a second adsorption tower of the second gas separation device to equalize the pressure between the first adsorption tower and the second adsorption tower. [6] A gas separation and recovery method for separating and recovering a required one component from a target gas containing at least three components, A first separation step involves separating a third component from the target gas using a first adsorption tower in a first gas separation apparatus of the pressure fluctuation adsorption type, A first regeneration step of desorbing the third component from the first adsorption tower, A second separation step is performed in which a second component is separated from the target gas by a second adsorption tower in a second gas separation apparatus using a pressure fluctuation adsorption method, A second regeneration step of desorbing the second component from the second adsorption tower, A gas separation and recovery method comprising: a pressure equalization step, which connects the first adsorption tower after the first separation step and before the first regeneration step with the second adsorption tower after the second regeneration step and before the second separation step, and equalizes the pressure between the first adsorption tower and the second adsorption tower. [7] The first adsorption tower repeatedly performs a first cycle including the first separation step, the pressure equalization step and the first regeneration step. The second adsorption tower repeats the second cycle, which includes the pressure equalization step, the second separation step, and the second regeneration step, The gas separation and recovery method according to [6], wherein the first cycle and the second cycle are synchronized so that the first adsorption tower and the second adsorption tower perform the pressure equalization process simultaneously. [8] A gas separation and recovery system for separating and recovering a required one component from a target gas containing at least three components, A manufacturing facility that discharges the aforementioned target gas as exhaust gas, [1] A gas separation and recovery apparatus as described in any one of paragraphs [1] to 4, A gas separation and recovery system comprising: a return route for returning a required component recovered by the gas separation and recovery device to the manufacturing equipment. [9] Combustion equipment that burns gaseous components as fuel, The gas separation and recovery system according to [8] further comprises a fuel supply path for supplying other gas components separated by the gas separation and recovery device to the combustion equipment.

[10] The gas separation and recovery system according to [8] or [9], wherein the manufacturing equipment is equipment for performing an oxo alcohol process. [Effects of the Invention]

[0009] The gas separation and recovery apparatus, gas separation and recovery method, and gas separation and recovery system of the present invention can improve the recovery rate and the removal rate of by-products when separating and recovering required components from a target gas containing multiple components. [Brief explanation of the drawing]

[0010] [Figure 1] This diagram illustrates the configuration of a gas separation and recovery apparatus 1 according to a first embodiment of the present invention, and a gas separation and recovery method using the same. [Figure 2] This diagram shows the operating status of the first adsorption towers 5A and 5B, which constitute the first gas separation device 2, and the open / closed status of each on-off valve in the gas separation and recovery device 1. [Figure 3] This diagram shows the operating status of the second adsorption towers 9A and 9B, which constitute the second gas separation device 3, and the open / closed status of each on-off valve in the gas separation and recovery device 1. [Figure 4] This diagram illustrates the configuration of a gas separation and recovery system 50 according to a second embodiment of the present invention, and a gas separation and recovery method using the same. [Figure 5]This is a schematic diagram for explaining a gas separation and recovery method using a gas separation and recovery system 50. [Figure 6] This is a schematic diagram for explaining a gas separation and recovery method using a gas separation and recovery system 50. [Figure 7] This is a schematic diagram for explaining a gas separation and recovery method using a gas separation and recovery system 50. [Figure 8] This is a schematic diagram for explaining a gas separation and recovery method using a gas separation and recovery system 50.

Embodiments for Carrying out the Invention

[0011] Hereinafter, a gas separation and recovery apparatus, a gas separation and recovery method, and a gas separation and recovery system to which the present invention is applied will be described in detail with reference to the drawings.

[0012] <First Embodiment> (Gas Separation and Recovery Apparatus) First, as a first embodiment of the present invention, for example, a gas separation and recovery apparatus 1 shown in FIG. 1 will be described. Note that FIG. 1 is a schematic diagram for explaining the configuration of the gas separation and recovery apparatus 1 and the gas separation and recovery method using the same.

[0013] The gas separation and recovery apparatus 1 of the present embodiment separates and recovers a required one component from a target gas containing at least three components. Specifically, this gas separation and recovery apparatus 1 includes a first gas separation apparatus 2 that removes a third component from a target gas (raw material gas) containing a first component, a second component, and a third component by a pressure swing adsorption method (PSA), a second gas separation apparatus 3 that separates and recovers the first component and the second component from the raw material gas from which the third component has been removed by a pressure swing adsorption method (PSA), and a pressure equalization gas path (gas path) 4 located between the first gas separation apparatus 2 and the second gas separation apparatus 3.

[0014] The first gas separation apparatus 2 includes a pair (two) first adsorption towers 5A and 5B, each containing an adsorbent S1 for adsorbing and desorbing a third component. The pair of first adsorption towers 5A and 5B have basically the same configuration, being formed in a hollow cylindrical shape with upper and lower piping 5a and 5b connected to their upper and lower ends.

[0015] The adsorbent S1 is filled inside the first adsorption towers 5A and 5B, respectively. In this embodiment, the first adsorption towers 5A and 5B are made of metal such as stainless steel (SUS304), but are not necessarily limited to metals that do not react with the raw material gas G1 or the regenerated gas G2 described later, and can withstand high temperature and high pressure.

[0016] The adsorbent S1 is not particularly limited as long as it is a substance that can adsorb and desorb the third component due to a pressure difference. For example, if the raw material gas (target gas) contains carbon dioxide (CO2), propane, and propylene, and the third component is carbon dioxide, then zeolite, activated alumina, and activated carbon can be used, and it is preferable to use molecular sieve activated carbon, which has excellent separation performance at room temperature.

[0017] The first gas separation apparatus 2 includes a raw material gas introduction unit 6 for introducing raw material gas G1 into the first adsorption towers 5A and 5B, and a regeneration gas introduction unit 7 for introducing regeneration gas G2 for regenerating the adsorbent S1 into the first adsorption towers 5A and 5B.

[0018] The raw material gas introduction section 6 introduces the raw material gas G1 into one of the first adsorption towers 5A through one raw material gas introduction pipe 6a that is branched from the lower pipe 5b of one of the first adsorption towers 5A. Meanwhile, the processed gas outlet section 16 discharges the raw material gas G3 (hereinafter referred to as the processed gas) from which the third component has been removed from one of the first adsorption towers 5A through one raw material gas outlet pipe 6b that is branched from the upper pipe 5a of one of the first adsorption towers 5A.

[0019] Similarly, the raw material gas introduction section 6 introduces the raw material gas G1 into the other first adsorption tower 5B through the other raw material gas introduction pipe 6c, which is branched from the lower pipe 5b of the other first adsorption tower 5B. On the other hand, the processing gas outlet section 16 discharges the processing gas G3 from the other first adsorption tower 5B through the other raw material gas outlet pipe 6d, which is branched from the upper pipe 5a of the other first adsorption tower 5B.

[0020] Furthermore, one raw material gas introduction pipe 6a and the other raw material gas introduction pipe 6c are connected at their respective inlet ends to form a common raw material gas introduction pipe 6e. In contrast, one raw material gas outlet pipe 6b and the other raw material gas outlet pipe 6d are connected at their respective outlets to form a common processed gas outlet pipe 6f.

[0021] Furthermore, the raw material gas introduction section 6 has an on-off valve V1A that opens and closes one raw material gas introduction pipe 6a, and an on-off valve V1B that opens and closes the other raw material gas introduction pipe 6c. Furthermore, the processing gas outlet section 16 includes an on-off valve V5A that opens and closes one processing gas outlet pipe 6b, and an on-off valve V5B that opens and closes the other processing gas outlet pipe 6d.

[0022] The regenerated gas introduction section 7 introduces regenerated gas G2 into one of the first adsorption towers 5A through one regenerated gas introduction pipe 7a that is branched from the upper pipe 5a of one of the first adsorption towers 5A. On the other hand, the regenerated gas introduction section 7 discharges regenerated gas G4 containing the third component desorbed from one of the first adsorption towers 5A (hereinafter simply referred to as regenerated gas) through one exhaust gas discharge pipe 7b that is branched from the lower pipe 5b of one of the first adsorption towers 5A.

[0023] Similarly, the regenerated gas introduction section 7 introduces regenerated gas G2 into the other first adsorption tower 5B through the other regenerated gas introduction pipe 7c, which is branched from the upper pipe 5a of the other first adsorption tower 5B. On the other hand, the regenerated gas introduction section 7 discharges regenerated gas G4 from the other first adsorption tower 5B through the other exhaust gas discharge pipe 7d, which is branched from the lower pipe 5b of the other first adsorption tower 5B.

[0024] Furthermore, one regenerated gas introduction pipe 7a and the other regenerated gas introduction pipe 7c are connected at their inlet ends to form a common regenerated gas introduction pipe 7e. In contrast, one exhaust gas outlet pipe 7b and the other exhaust gas outlet pipe 7d are connected at their outlet ends to form a common exhaust gas outlet pipe 7f.

[0025] Furthermore, the regenerated gas introduction section 7 includes an on-off valve V4A for opening and closing one regenerated gas introduction pipe 7a, an on-off valve V2A for opening and closing one exhaust gas outlet pipe 7b, an on-off valve V4B for opening and closing the other regenerated gas introduction pipe 7c, and a carbon dioxide removal side on-off valve V2B for opening and closing the other exhaust gas outlet pipe 7d.

[0026] In this embodiment, the raw material gas introduction pipes 6a, 6c, 6e, the processed gas outlet pipes 6b, 6d, 6f, the regenerated gas introduction pipes 7a, 7c, 7e, and the exhaust gas outlet pipes 7b, 7d, 7f are made of metals such as stainless steel (SUS304), but the material is not necessarily limited to stainless steel, as long as it does not react with the raw material gas G1 or regenerated gas G2 and can withstand high temperature and high pressure.

[0027] Furthermore, in this embodiment, the on-off valves V1A, V1B, V2A, V2B, V4A, V4B, V5A, and V5B are not particularly limited. Any valve that does not react with the raw material gas G1 or regenerated gas G2 and can withstand high temperature and high pressure is acceptable. For example, various types of on-off valves such as diaphragm valves, ball valves, and butterfly valves can be used.

[0028] The flow control valve 8 is installed in the raw material gas introduction piping 6e with the aim of preventing a decrease in raw material gas pressure and a decrease in adsorption performance due to excessive flow to the first adsorption tower.

[0029] The second gas separation apparatus 3 comprises a pair (two) second adsorption towers 9A and 9B, each containing an adsorbent S2 for adsorbing and desorbing the second component. The pair of second adsorption towers 9A and 9B have basically the same configuration, being formed in a hollow cylindrical shape with upper and lower piping 9a and 9b connected to their upper and lower ends.

[0030] The adsorbent S2 is filled inside the second adsorption towers 9A and 9B, respectively. In this embodiment, the second adsorption towers 9A and 9B are made of metal such as stainless steel (SUS304), but are not necessarily limited to metals that do not react with the processing gas G3 or the pressure equalizing gas G7 (described later) and can withstand high temperature and high pressure.

[0031] The adsorbent S2 is not particularly limited as long as it is a substance that can adsorb and desorb the second component due to a pressure difference. For example, when the processed gas contains propane and propylene, and the second component is propylene, molecular sieve activated carbon and activated carbon can be used, and it is preferable to use molecular sieve activated carbon, which has excellent separation performance at room temperature.

[0032] The second gas separation apparatus 3 includes a processing gas introduction unit 10 for introducing the processing gas G3 into the second adsorption towers 9A and 9B.

[0033] The processing gas introduction section 10 introduces processing gas G3 into one of the second adsorption towers 9A through one processing gas introduction pipe 10a that branches off from the lower side piping 9b of one of the second adsorption towers 9A. Meanwhile, the processing gas introduction section 10 discharges the first component gas G5 separated and recovered from one of the second adsorption towers 9A through one first component discharge pipe 10b that branches off from the upper side piping 9a of one of the second adsorption towers 9A. Meanwhile, the processing gas introduction section 10 discharges the second component gas G6 separated and recovered from one of the second adsorption towers 9A through one second component discharge pipe 10c that branches off from the lower side piping 9b of one of the second adsorption towers 9A.

[0034] Similarly, the processing gas introduction section 10 introduces the processing gas G3 into the other second adsorption tower 9B through the other processing gas introduction pipe 10d, which is branched from the lower piping 9b of the other second adsorption tower 9B. Meanwhile, the processing gas introduction section 10 discharges the first component gas G5 separated and recovered from the other second adsorption tower 9B through the other first component discharge pipe 10e, which is branched from the upper piping 9a of the other second adsorption tower 9B. Meanwhile, the processing gas introduction section 10 discharges the second component gas G6 separated and recovered from the other second adsorption tower 9B through the other second component discharge pipe 10f, which is branched from the lower piping 9b of the other second adsorption tower 9B.

[0035] Furthermore, one processing gas introduction pipe 10a and the other processing gas introduction pipe 10d are connected at their respective inlet ends to form a common processing gas introduction pipe 10g. The processing gas introduction pipe 10g is also connected to the processing gas outlet pipe 6f on the first gas separation device 2 side.

[0036] In contrast, one first component outlet pipe 10b and the other first component outlet pipe 10e are connected at their respective outlets to form a common first component outlet pipe 10h. Also, one second component outlet pipe 10c and the other second component outlet pipe 10f are connected at their respective outlets to form a common second component outlet pipe 10i.

[0037] The processing gas introduction section 10 has a pressure control valve 11 located in the first component discharge pipe 10h. The pressure control valve 11 is provided for the purpose of dischargeing the non-adsorbed gas in the second adsorption tower to the outside of the adsorption tower.

[0038] Furthermore, the processing gas introduction section 10 includes an on-off valve V6A for opening and closing one processing gas introduction pipe 10a, an on-off valve V9A for opening and closing one first component outlet pipe 10b, an on-off valve V7A for opening and closing one second component outlet pipe 10c, an on-off valve V6B for opening and closing the other processing gas introduction pipe 10d, an on-off valve V9B for opening and closing the other first component outlet pipe 10e, and a sixth on-off valve V7B for opening and closing the other second component outlet pipe 10f.

[0039] As described above, to introduce a portion of the first component gas G5, which is separated and recovered from the treatment gas G3, as the regenerated gas G2 into the first adsorption towers 5A and 5B, the regenerated gas introduction section 7 has regenerated gas introduction pipes 7g and 7h branched from the regenerated gas introduction pipe 7e, and regenerated gas outlet valves V10A and V10B.

[0040] The regenerated gas introduction pipe 7g is connected to the upper pipe 9a of the second adsorption tower 9A, and a portion of the first component gas G5 discharged from the upper pipe 9a is introduced into the regenerated gas introduction pipe 7e as regenerated gas G2.

[0041] Meanwhile, the regenerated gas introduction pipe 7h is connected to the upper pipe 9a of the second adsorption tower 9B, and a portion of the first component gas G5 discharged from the upper pipe 9a is introduced into the regenerated gas introduction pipe 7e as regenerated gas G2.

[0042] Furthermore, a pressure control valve 12 is located in the regenerated gas introduction pipe 7e. The pressure control valve 12 is provided for the purpose of maintaining the adsorption pressure of the second adsorption tower.

[0043] In this embodiment, the processing gas introduction pipes 10a, 10d, 10g, the first component discharge pipes 10b, 10e, 10h, the second component discharge pipes 10c, 10f, 10i, and the regenerated gas introduction pipes 7g, 7h can be basically the same as the raw material gas introduction pipes 6a, 6c, 6e, the processing gas outlet pipes 6b, 6d, 6f, the regenerated gas introduction pipes 7a, 7c, 7e, and the exhaust gas outlet pipes 7b, 7d, 7f described above. Also, the on-off valves V6A, V6B, V7A, V7B, V9A, V9B, V10A, V10B in this embodiment can be basically the same as the on-off valves V1A, V1B, V2A, V2B, V4A, V4B, V5A, V5B described above.

[0044] The pressure reducing pump 13 is installed in the second component outlet pipe 10i and reduces the pressure (vacuum) inside the second adsorption towers 9A and 9B. The pressure reducing pump 13 is not particularly limited as long as it can reduce the pressure inside the second adsorption towers 9A and 9B, and various types of pressure reducing pumps can be used. For example, the pressure reducing pump 13 can be a diaphragm vacuum pump, a Roots vacuum pump, a screw vacuum pump, or a scroll vacuum pump.

[0045] The pressure equalization gas path 4 is located between the first gas separator 2 and the second gas separator 3. The pressure equalization gas path 4 merges with the pressure equalization gas outlet pipes 4a and 4b on the first gas separator 2 side. The pressure equalization gas path 4 also branches off to the pressure equalization gas introduction pipes 4c and 4d on the second gas separator 3 side.

[0046] The pressure equalization gas outlet pipe 4a is connected to the upper pipe 5a of the first adsorption tower 5A, and the raw material gas G7 from which the third component has been removed (hereinafter referred to as pressure equalization gas) discharged from the upper pipe 5a is introduced into the pressure equalization gas path 4. Furthermore, the pressure equalization gas outlet pipe 4b is connected to the upper pipe 5a of the first adsorption tower 5B, and the pressure equalization gas G7 discharged from the upper pipe 5a is introduced into the pressure equalization gas path 4.

[0047] The pressure equalization gas introduction pipe 4c is connected to the lower pipe 9b of the second adsorption tower 9A, and introduces the pressure equalization gas G7, which is led out from the pressure equalization gas path 4, into the second adsorption tower 9A. Furthermore, the pressure equalization gas introduction pipe 4d is connected to the lower pipe 9b of the second adsorption tower 9B, and the pressure equalization gas G7 derived from the pressure equalization gas path 4 is introduced into the second adsorption tower 9B.

[0048] Furthermore, the pressure equalization gas path 4 includes an on-off valve V3A that opens and closes one pressure equalization gas outlet pipe 4a, an on-off valve V3B that opens and closes one pressure equalization gas outlet pipe 4b, an on-off valve V8A that opens and closes one pressure equalization gas introduction pipe 4c, and an on-off valve V8B that opens and closes the other pressure equalization gas introduction pipe 4d.

[0049] The pressure equalization gas path 4 connects the first adsorption tower (after adsorption but before regeneration) of the pair of first adsorption towers 5A and 5B, and the second adsorption tower (after regeneration but before adsorption) of the pair of second adsorption towers 9A and 9B. By providing the pressure equalization gas path 4, even while the processed gas G3 discharged from one of the pair of first adsorption towers 5A and 5B (e.g., first adsorption tower 5A) is being supplied to one of the pair of second adsorption towers 9A and 9B (e.g., second adsorption tower 9A), the pressure equalization gas G7 discharged from the first adsorption tower (after adsorption but before regeneration) of the pair of first adsorption towers 5A and 5B (e.g., first adsorption tower 5B) can be introduced to the second adsorption tower (after regeneration but before adsorption) of the pair of second adsorption towers 9A and 9B (e.g., second adsorption tower 9B). In other words, the pressure can be equalized between the first adsorption tower 5A, 5B (of the pair of first adsorption towers) after adsorption but before regeneration, and the second adsorption tower 9A, 9B (of the pair of second adsorption towers) after regeneration but before adsorption.

[0050] Furthermore, the pressure equalization gas outlet pipes 4a, 4b and pressure equalization gas inlet pipes 4c, 4d that constitute the pressure equalization gas path 4 of this embodiment can be basically the same as the raw material gas inlet pipes 6a, 6c, 6e, processed gas outlet pipes 6b, 6d, 6f, regenerated gas inlet pipes 7a, 7c, 7e, and exhaust gas outlet pipes 7b, 7d, 7f described above. Also, the on-off valves V3A, V3B, V8A, V8B of this embodiment can be basically the same as the on-off valves V1A, V1B, V2A, V2B, V4A, V4B, V5A, V5B described above.

[0051] (Gas separation and recovery method) Next, the gas separation and recovery method using the gas separation and recovery apparatus 1 described above will be explained with reference to Figures 1 to 3. The gas separation and recovery method of this embodiment is a gas separation and recovery method that separates and recovers a required one component from a target gas (raw material gas) containing at least three components (first to third components), wherein the third component is separated from the raw material gas by a first gas separation device 2 of the pressure fluctuation adsorption (PSA) type, and the second component and the first component are separated from the raw material by a second gas separation device 3 of the pressure fluctuation adsorption (PSA) type, and either one of the pair of first adsorption towers 5A and 5B of the first gas separation device 2 and either one of the pair of second adsorption towers 9A and 9B of the second gas separation device 3 are connected by a pressure equalization gas path 4, and the pressure is equalized between the first adsorption tower and the second adsorption tower.

[0052] Specifically, the gas separation and recovery method of this embodiment includes: a first separation step of separating a third component from a raw material gas using one of the pair of first adsorption towers 5A and 5B of a first gas separation device 2 of the pressure fluctuation adsorption (PSA) type; a first regeneration step of desorbing the third component from the first adsorption tower; a second separation step of separating a second component from the target gas using one of the pair of second adsorption towers 9A and 9B of a second gas separation device 3 of the pressure fluctuation adsorption (PSA) type; a second regeneration step of desorbing the second component from the second adsorption tower; and a pressure equalization step of connecting the first adsorption tower after the first separation step and before the first regeneration step with the second adsorption tower after the second regeneration step and before the second separation step, and equalizing the pressure between the first adsorption tower and the second adsorption tower.

[0053] In the gas separation and recovery method of this embodiment, first, in the first gas separation apparatus 2, as shown in Figure 1, the third component is removed from the target gas containing the first to third components, which will become the raw material gas G1.

[0054] Specifically, in the first gas separation apparatus 2, while one first adsorption tower 5A performs a first separation process in which it adsorbs and removes the third component contained in the raw material gas G1 onto the adsorbent S1, the other first adsorption tower 5B performs a first regeneration process in which it regenerates the adsorbent S1 by desorbing the third component adsorbed onto the adsorbent S1.

[0055] In other words, in the gas separation and recovery method of this embodiment, as the first separation step of one of the first adsorption towers 5A, the raw material gas G1 is pressurized to a predetermined pressure (for example, about 500 to 700 kPaG in this embodiment) and introduced into one of the first adsorption towers 5A, and the third component contained in this raw material gas G1 is adsorbed and removed by the adsorbent S1.

[0056] At this time, in the first gas separation device 2, valves V1A and V5A are opened, and valves V2A, V3A, and V4A are closed. As a result, the raw material gas G1 is introduced under pressure from the lower piping 5b side of one of the first adsorption towers 5A through the raw material gas introduction pipe 6e and one of the raw material gas introduction pipes 6a.

[0057] The raw material gas G1 introduced into one of the first adsorption towers 5A passes through the first adsorption tower 5A, and as it does so, the third component contained in the raw material gas G1 is adsorbed and removed by the adsorbent S1. The raw material gas (processed gas) G3 from which the third component has been removed is discharged from the upper side piping 5a of one of the first adsorption towers 5A through the processed gas discharge piping 6b and processed gas discharge piping 6f.

[0058] In contrast, in the gas separation and recovery method of this embodiment, as the first regeneration step of the other first adsorption tower 5B, a portion of the first component gas G5 separated and recovered from the processed gas G3 in the second gas separation device 3 (described later) is introduced into the other first adsorption tower 5B as regenerated gas G2.

[0059] At this time, in the first gas separation device 2, as the first regeneration process, the on-off valves V2B and V4B are opened and the on-off valves V1B, V3B and V5B are closed. As a result, regenerated gas G2 is introduced from the upper side piping 5a of the other first adsorption tower 5B through the regenerated gas introduction pipe 7e and the other regenerated gas introduction pipe 7c.

[0060] The regenerated gas G2 introduced into the other first adsorption tower 5B passes through the other first adsorption tower 5B, purging any third component remaining in it to the outside of the other first adsorption tower 5B. The regenerated gas G4 containing the third component is discharged from the lower piping 5b side of the other first adsorption tower 5B through the exhaust gas outlet piping 7d and exhaust gas outlet piping 7f of the other first adsorption tower 5B. This restores the adsorption capacity of the adsorbent S1 to the third component, and the adsorbent S1 can be regenerated.

[0061] In the gas separation and recovery method of this embodiment, when the ability of one first adsorption tower 5A to adsorb the third component of the adsorbent S1 decreases, the other first adsorption tower 5B switches to performing the first separation step, and one first adsorption tower 5A switches to performing the first regeneration step. Then, while the other first adsorption tower 5B is performing the first separation step, one first adsorption tower 5A performs the first regeneration step.

[0062] In other words, in the gas separation and recovery method of this embodiment, as the first separation step of the other first adsorption tower 5B, the raw material gas G1 is pressurized to a predetermined pressure (for example, about 500 to 700 kPaG in this embodiment) and introduced into the other first adsorption tower 5B, and the third component contained in this raw material gas G1 is adsorbed and removed by the adsorbent S1.

[0063] At this time, in the first gas separation device 2, valves V1B and V5B are opened, and valves V2B, V3B, and V4B are closed. As a result, the raw material gas G1 is introduced under pressure from the lower piping 5b side of the other first adsorption tower 5B through the raw material gas introduction pipe 6e and one of the raw material gas introduction pipes 6c.

[0064] The raw material gas G1 introduced into the other first adsorption tower 5B is adsorbed and removed by the adsorbent S1 as it passes through the other first adsorption tower 5B, thereby removing the third component contained in the raw material gas G1. The raw material gas (processed gas) G3 from which the third component has been removed is discharged from the upper side piping 5a of the other first adsorption tower 5B through the other processed gas discharge piping 6d and processed gas discharge piping 6f.

[0065] In contrast, in the gas separation and recovery method of this embodiment, as the first regeneration step of one of the first adsorption towers 5A, a portion of the first component gas G5 separated and recovered from the processed gas G3 in the second gas separation device 3 (described later) is introduced into the first adsorption tower 5A as regenerated gas G2.

[0066] At this time, in the first gas separation device 2, as the first regeneration process, the on-off valves V2A and V4A are opened and the on-off valves V1A, V3A and V5A are closed. As a result, regenerated gas G2 is introduced from the upper piping 5a side of one of the first adsorption towers 5A through the regenerated gas introduction pipe 7e and the other regenerated gas introduction pipe 7a.

[0067] The regenerated gas G2 introduced into one of the first adsorption towers 5A passes through the first adsorption tower 5A, purging any third component remaining within it to the outside of the first adsorption tower 5A. The regenerated gas G4 containing the third component is discharged from the lower piping 5b side of one of the first adsorption towers 5A through the exhaust gas outlet piping 7b and exhaust gas outlet piping 7f of the other. This restores the adsorbent S1's ability to adsorb the third component, thereby regenerating the adsorbent S1.

[0068] As described above, in the gas separation and recovery method of this embodiment, the third component contained in the raw material gas G1 can be continuously removed by alternately switching between the first separation step and the first regeneration step between the first adsorption tower 5A and the other first adsorption tower 5B.

[0069] Next, in the gas separation and recovery method of this embodiment, as shown in Figure 1, the second gas separation apparatus 3 separates and recovers the second component and the first component from the raw material gas (processed gas) G3 from which the third component has been removed.

[0070] Specifically, in this second gas separation apparatus 3, while one second adsorption tower 9A performs a first component recovery process (second separation process) in which it recovers the first component G5 discharged from the second adsorption tower 9A by selectively adsorbing the second component contained in the processed gas G3 onto the adsorbent S2, the other second adsorption tower 9B performs a second component recovery process (second regeneration process) in which it recovers the second component gas G6 discharged from the other second adsorption tower 9B by desorbing the second component adsorbed onto the adsorbent S2.

[0071] In other words, in the gas separation and recovery method of this embodiment, as the first component recovery step (second separation step) of one of the second adsorption towers 9A, a treated gas G3 at a predetermined pressure (for example, about 475 to 675 kPaG in this embodiment) is introduced into one of the second adsorption towers 9A, and the second component contained in this treated gas G3 is adsorbed and removed by the adsorbent S2.

[0072] At this time, the second gas separation device 3 opens the on-off valves V6A and V9A and closes the on-off valves V7A, V8A and V10A. As a result, the processed gas G3 is introduced under pressure from the lower piping 9b side of one of the second adsorption towers 9A through the processed gas introduction pipe 10g and one of the processed gas introduction pipes 10a, and the inside of one of the second adsorption towers 9A is pressurized to a predetermined pressure (in this embodiment, for example, about 475 to 675 kPaG).

[0073] The processed gas G3 introduced into the second adsorption tower 9A is separated from the first component by the second component as it passes through the second adsorption tower 9A, due to the adsorption of the second component contained in the processed gas G3 by the adsorbent S2. The first component separated from the processed gas G3 is discharged from the upper side piping 9a of the second adsorption tower 9A through the first component discharge piping 10b and the first component discharge piping 10h, and recovered as high-purity first component gas G5.

[0074] In contrast, in the gas separation and recovery method of this embodiment, as a second component recovery step (second regeneration step) of the other second adsorption tower 9B, the pressure inside the other second adsorption tower 9B is reduced to a predetermined pressure (in this embodiment, for example, about -70 to -90 kPaG) using a depressurizing pump 13. As a result, the second component adsorbed on the adsorbent S2 is desorbed.

[0075] At this time, in the second gas separation device 3, valve V7B is opened and valves V6B, V8B, V9B, and V10B are closed. As a result, the second component detached from the adsorbent S2 is discharged from the lower piping 9b side of the other second adsorption tower 9B through the other second component discharge piping 10f and second component discharge piping 10i, and recovered as high-purity second component gas G6. In addition, the adsorbent S2 can be regenerated.

[0076] In the gas separation and recovery method of this embodiment, when the ability of one second adsorption tower 9A to adsorb the second component of the adsorbent S2 decreases, the other second adsorption tower 9B switches to performing the first component recovery process (second separation process), while the other second adsorption tower 9A switches to performing the second component recovery process (second regeneration process). Then, while the other second adsorption tower 9B is performing the first component recovery process (second separation process), the other second adsorption tower 9A performs the second component recovery process (second regeneration process).

[0077] In other words, in the gas separation and recovery method of this embodiment, as the first component recovery step (second separation step) of the other second adsorption tower 9B, a treated gas G3 at a predetermined pressure (for example, about 475 to 675 kPaG in this embodiment) is introduced into the other second adsorption tower 9B, and the second component contained in this treated gas G3 is adsorbed and removed by the adsorbent S2.

[0078] At this time, in the second gas separation device 3, the on-off valves V6B and V9B are opened, and the on-off valves V7B, V8B and V10B are closed. As a result, the processed gas G3 is introduced under pressure from the lower piping 9b side of the other second adsorption tower 9B through the processed gas introduction pipe 10g and the other processed gas introduction pipe 10d, and the inside of the other second adsorption tower 9B is pressurized to a predetermined pressure (in this embodiment, for example, about 475 to 675 kPaG).

[0079] The processed gas G3 introduced into the other second adsorption tower 9B is separated from the first component by the adsorbent S2 as it passes through the other second adsorption tower 9B, which adsorbs the second component contained in the processed gas G3. The first component separated from the processed gas G3 is discharged from the upper side piping 9a of the other second adsorption tower 9B through the other first component discharge piping 10e and first component discharge piping 10h, and recovered as high-purity first component gas G5.

[0080] In contrast, in the gas separation and recovery method of this embodiment, as a second component recovery step (second regeneration step) of one of the second adsorption towers 9A, the pressure inside one of the second adsorption towers 9A is reduced to a predetermined pressure (for example, about -70 to -90 kPaG in this embodiment) using a depressurizing pump 13. As a result, the second component adsorbed on the adsorbent S2 is desorbed.

[0081] At this time, in the second gas separation device 3, valve V7A is opened and valves V6A, V8A, V9A, and V10A are closed. As a result, the second component detached from the adsorbent S2 is discharged from the lower piping 9b side of one of the second adsorption towers 9A through one of the second component discharge pipes 10c and 10i, and recovered as high-purity second component gas G6. In addition, the adsorbent S2 can be regenerated.

[0082] As described above, in the gas separation and recovery method of this embodiment, it is possible to continuously separate and recover the second component and the first component contained in the processed gas G3 by alternately switching between the first component recovery process (second separation process) and the second component recovery process (second regeneration process) between one second adsorption tower 9A and the other second adsorption tower 9B.

[0083] Furthermore, in the gas separation and recovery method of this embodiment, when switching from the first component recovery process (second separation process) to the second component recovery process (second regeneration process), a purging process may be performed in which a portion of the first component gas G5 recovered in the first component recovery process (second separation process) is introduced as regenerated gas G2 into the first adsorption towers 5A and 5B.

[0084] Specifically, when switching from the first component recovery process (second separation process) to the second component recovery process (second regeneration process) in one of the second adsorption towers 9A described above, a portion of the first component gas G5 recovered in the first component recovery process (second separation process) of the first adsorption tower 9A is introduced into the other first adsorption tower 5B as regenerated gas G2, as part of the regeneration process of the other first adsorption tower 5B.

[0085] At this time, in the second gas separation unit 3, valves V6A and V10A are opened, and valves V7A, V8A, and V9A are closed. Also, in the second component recovery process (second separation process) of the other second adsorption tower 9B, the recovery of the second component gas G6 is continued. As a result, a portion of the first component gas G5 is introduced into the other first adsorption tower 5B as regenerated gas G2.

[0086] After the purging process, one of the second adsorption towers 9A proceeds to the second component recovery process (second regeneration process) described above. Furthermore, when switching from the first component recovery process (second separation process) to the second component recovery process (second regeneration process) in the other second adsorption tower 9B, the purging process can be performed using the same operation as the purging process of the other second adsorption tower 9A described above.

[0087] Furthermore, in the gas separation and recovery method of this embodiment, when switching from the first component recovery step (second separation step) to the second component recovery step (second regeneration step) described above, it is preferable to perform a depressurization step in which the pressure inside the pressurized second adsorption towers 9A and 9B is released, thereby depressurizing the pressure inside these second adsorption towers 9A and 9B.

[0088] In this embodiment of the gas separation and recovery method, the first adsorption tower after the first separation step and before the first regeneration step is connected to the second adsorption tower after the second regeneration step and before the second separation step, and a pressure equalization step is performed to equalize the pressure between the first adsorption tower and the second adsorption tower.

[0089] In other words, as described above, in the first gas separation apparatus 2, when one first adsorption tower 5A performs the first separation process and the other first adsorption tower 5B performs the first regeneration process, when the ability of one first adsorption tower 5A to adsorb the third component of the adsorbent S1 decreases, the other first adsorption tower 5B switches to performing the first separation process and the one first adsorption tower 5A switches to performing the first regeneration process. Similarly, in the second gas separation apparatus, if one second adsorption tower 9A performs the first component recovery process (second separation process) and the other second adsorption tower 9B performs the second component recovery process (second regeneration process), when the ability of one second adsorption tower 9A to adsorb the second component of the adsorbent S2 decreases, the other second adsorption tower 9B switches to perform the second separation process and the one second adsorption tower 9A switches to perform the second regeneration process. In the gas separation and recovery method of this embodiment, one first adsorption tower 5A, which has completed the first separation step but has not yet started the first regeneration step, and the other second adsorption tower 9B, which has completed the second regeneration step but has not yet started the second separation step, are connected by a pressure equalizing gas path 4.

[0090] At this time, in the first gas separation device 2, valve V3A is opened and valves V1A, V2A, V4A, and V5A are closed. Meanwhile, in the second gas separation device 3, valve V8B is opened, and valves V6B, V7B, V9B, and V10B are closed. As a result, the pressure in one of the first adsorption towers 5A is released, and the gas containing the second and first components, which is discharged from the first adsorption tower 5A, is discharged into the pressure equalization gas path 4 as pressure equalization gas G7. At the same time, pressure equalization gas G7 is introduced into the other second adsorption tower 9B, and the pressure in the other second adsorption tower 9B is increased.

[0091] Thus, in the gas separation and recovery method of this embodiment, by performing a pressure equalization step to equalize the pressure between the first adsorption tower and the second adsorption tower, the first and second components remaining in the first adsorption towers 5A and 5B can be recovered in the second adsorption towers 9A and 9B, thereby improving the recovery rate of the first or second component.

[0092] After the pressure equalization process, one of the first adsorption towers 5A proceeds to the first regeneration process described above. The other, the second adsorption tower 9B proceeds to the first component recovery process (second separation process) described above. Furthermore, in the gas separation and recovery method of this embodiment, it is possible to perform a pressure equalization process between the other first adsorption tower 5B, which has completed the first separation process but has not yet started the first regeneration process, and the other second adsorption tower 9A, which has completed the second regeneration process but has not yet started the second separation process, using the same operation as the pressure equalization process described above.

[0093] Furthermore, in the gas separation and recovery method of this embodiment, it is preferable that the first adsorption towers 5A and 5B each repeat a cycle (first cycle) including the first separation step, pressure equalization step, and first regeneration step described above, and the second adsorption towers 9A and 9B each repeat a cycle (second cycle) including the pressure equalization step, first component recovery step (second separation step), and second component recovery step (second regeneration step) described above, and that the first and second adsorption towers synchronize the first and second cycles so that the pressure equalization step described above is performed simultaneously.

[0094] Here, Figure 2 shows the operating state of the first adsorption towers 5A and 5B, which constitute the first gas separation device 2 in the gas separation and recovery device 1 of this embodiment, and the open / closed state of each on-off valve. Figure 3 shows the operating state of the second adsorption towers 9A and 9B, which constitute the second gas separation device 3 in the gas separation and recovery device 1 of this embodiment, and the open / closed state of each on-off valve.

[0095] Specifically, in the gas separation and recovery method using this gas separation and recovery device 1, as shown in Figures 2 and 3, the cycles of the first adsorption towers 5A and 5B (first cycle) and the second adsorption towers 9A and 9B (second cycle) can be synchronized so that the pressure equalization process is performed simultaneously between the first adsorption towers 5A and 5B of the first gas separation device 2 and the second adsorption towers 9A and 9B of the second gas separation device 3. This makes it possible to improve the recovery rate of the first or second component without reducing the operating efficiency of the gas separation and recovery device 1.

[0096] As described above, in the gas separation and recovery apparatus 1 and gas separation and recovery method of this embodiment, the first adsorption towers (5A, 5B) after the first separation process and before the first regeneration process are connected to the second adsorption towers (9A, 9B) after the second regeneration process and before the second separation process. By performing a pressure equalization process to equalize the pressure between the first and second adsorption towers, it is possible to improve the recovery rate and the removal rate of by-products when separating and recovering the required components from a target gas containing multiple components.

[0097] <Second Embodiment> (Gas separation and recovery system) Next, as a second embodiment of the present invention, a gas separation and recovery system 50, as shown in Figure 4, will be described. Figure 4 is a diagram illustrating the configuration of the gas separation and recovery system 50 and a gas separation and recovery method using it.

[0098] The gas separation and recovery system 50 of this embodiment separates and recovers a required one component from a target gas containing at least three components. The gas separation and recovery system 50 comprises a manufacturing facility 52 that discharges the target gas as exhaust gas, a gas separation and recovery device 51, a return route 53 that returns the required gas components recovered by the gas separation and recovery device 51 to the manufacturing facility 52, a combustion facility 54 that burns the unwanted gas components as fuel, and a fuel supply route 55 that supplies the unwanted gas components separated by the gas separation and recovery device 51 to the combustion facility 54.

[0099] The manufacturing equipment 52 is not particularly limited as long as it is equipment that discharges a target gas containing at least three components as exhaust gas. In the gas separation and recovery system of this embodiment, the case in which the manufacturing equipment 52 is equipment that performs an oxo alcohol process will be described below as an example.

[0100] Manufacturing facility 52 is an oxo alcohol process plant that produces butyraldehyde, an intermediate product, using propylene as a raw material. This manufacturing facility 52 discharges a target gas containing one or more selected from the group consisting of butyraldehyde, carbon dioxide, propane, and propylene as exhaust gas into the exhaust gas path L1.

[0101] The exhaust gas path L1 is equipped with a compressor 56 for compressing the exhaust gas and a gas-liquid separator 57 for cooling the exhaust gas and liquefying and recovering the butyraldehyde contained in the exhaust gas. In the gas-liquid separator 57, the liquid phase obtained when the exhaust gas is cooled is recovered. The recovered liquid phase is then led to the aldehyde recovery tank 58. Furthermore, the aldehyde recovery tank 58 stores the liquid phase discharged from the gas-liquid separator 57, discharges the gas phase portion to the primary side of the compressor 56 in the exhaust gas path L1, and returns the liquid phase portion (butyraldehyde) to the manufacturing equipment 52 via the aldehyde recovery path L2.

[0102] (Gas separation and recovery device) The gas separation and recovery device 51 of this embodiment differs from the gas separation and recovery device 1 of the first embodiment described above in that it further includes a third gas separation device 14. Therefore, components of the gas separation and recovery device 51 that are common to the gas separation and recovery device 1 are denoted by the same reference numerals and their descriptions are omitted.

[0103] The third gas separator 14 is located on the primary side of the first gas separator 2 and removes butyraldehyde as a fourth component other than the first to third components from the exhaust gas (target gas) using a temperature fluctuation adsorption (TSA) method.

[0104] The third gas separation apparatus 14 is equipped with a pair (two) third adsorption towers 15A and 15B, each containing an adsorbent S3 for adsorbing and desorbing butyraldehyde (the fourth component). The pair of third adsorption towers 15A and 15B have basically the same configuration, being formed in a hollow cylindrical shape with upper and lower piping connected to their upper and lower ends.

[0105] The adsorbent S3 is filled inside the third adsorption towers 15A and 15B, respectively. In this embodiment, the third adsorption towers 15A and 15B are made of metal such as stainless steel (SUS304), but are not necessarily limited to metals that do not react with exhaust gas or the regenerated gas G4 mentioned above and can withstand high temperature and high pressure.

[0106] The adsorbent S3 is not particularly limited as long as it is a substance that can adsorb and desorb butyraldehyde (the fourth component) due to a temperature difference. As the adsorbent S3, for example, activated carbon, silica, or silica-alumina can be used, and activated carbon is preferred.

[0107] The third gas separation unit 14 is connected to an exhaust gas path L1 for introducing exhaust gas into the third adsorption towers 15A and 15B, a raw material gas outlet path L3 for releasing raw material gas G1 from which the fourth component has been removed from the exhaust gas, a regenerated gas introduction path L4 for introducing regenerated gas G4 released from the first gas separation unit 2 into the third adsorption towers 15A and 15B as regenerated gas, and an off-gas outlet path L5 for releasing off-gas from within the third adsorption towers 15A and 15B during regeneration. Furthermore, each path L1, L3, L4, and L5 branches out and is connected to the upper and lower piping of the third adsorption towers 15A and 15B, respectively. Furthermore, the raw material gas outlet route L3 is connected to the raw material gas introduction pipe 6e on the first gas separation unit 2 side. In addition, the regenerated gas introduction route L4 is connected to the exhaust gas outlet pipe 7f on the first gas separation unit 2 side.

[0108] The regenerated gas introduction path L4 is equipped with a heat exchanger 59 that cools the regenerated gas to the required temperature. Furthermore, the off-gas outlet path L5 is equipped with a gas-liquid separator 60 that cools and separates the off-gas discharged from the third adsorption towers 15A and 15B during regeneration. An aldehyde recovery path L2 is connected to the liquid phase portion of the gas-liquid separator 60 to return butyraldehyde to the manufacturing equipment 52. An exhaust path L6 is connected to the gas phase portion of the gas-liquid separator 60 to discharge off-gas G8, which contains carbon dioxide, a third component. A pressure control valve 61 is provided in the exhaust path L6. The exhaust path L6 is also connected to a fuel supply path 55 that supplies fuel to the combustion equipment 54.

[0109] The gas separation and recovery device 51 of this embodiment has a first component discharge path L7. The first component discharge path L7 is connected to the first component discharge pipe 10h on the second separation device 3 side, and on the opposite side it merges with the exhaust path L6 and is connected to the fuel supply path 55.

[0110] (Gas separation and recovery system) The return route 53 is connected to the second component outlet pipe 10i on the second separation device 3 side. The return route 53 is also equipped with a buffer tank 62 for temporarily storing the second component, propylene, and a compressor 63 for pressurizing the propylene.

[0111] The combustion equipment 54 is a device that burns unwanted gaseous components as fuel. By supplying the heat source obtained in this way to various heat exchangers, the energy efficiency of the gas separation and recovery system 50 can be improved.

[0112] The fuel supply path 55 is located between the gas separation and recovery device 51 and the combustion equipment 54. A compressor 64 is also provided in the fuel supply path 55. The fuel supply path 55 recovers various gases discharged from the gas separation and recovery device 51, pressurizes them, and then supplies them to the combustion equipment 54 as fuel gas.

[0113] (Gas separation and recovery method) Next, a gas separation and recovery method using the gas separation and recovery system 50 described above will be explained with reference to Figures 4 to 8. The gas separation and recovery method of this embodiment separates butyraldehyde, the product, and propylene, the raw material, from the exhaust gas discharged from the manufacturing equipment 52, which is an oxo alcohol process plant, and returns them to the manufacturing equipment 52 as the product and raw material.

[0114] Specifically, the gas separation and recovery method of this embodiment is a gas separation and recovery method that separates and recovers two required components from exhaust gas containing four components (first to fourth components). A third gas separator 14 using temperature fluctuation adsorption (TSA) separates butyraldehyde (fourth component) from the exhaust gas, a first gas separator 2 using pressure fluctuation adsorption (PSA) separates carbon dioxide (third component) from the raw material gas, and a second gas separator 3 using pressure fluctuation adsorption (PSA) separates propylene (second component) and propane (first component) from the raw material, while returning butyraldehyde (fourth component) and propylene (second component) to the manufacturing equipment 52. In this case, in the gas separation and recovery device 51, similar to the gas separation and recovery device 1 of the first embodiment described above, one of the pair of first adsorption towers 5A and 5B of the first gas separation device 2 and one of the pair of second adsorption towers 9A and 9B of the second gas separation device 3 are connected by a pressure equalization gas path 4, and the recovery rate of propylene (second component) is improved by equalizing the pressure between the first adsorption tower and the second adsorption tower.

[0115] Here, Figures 5 to 8 are system diagrams illustrating the gas separation and recovery method using the gas separation and recovery system 50 of this embodiment.

[0116] (TSA: Adsorption-15B, Desorption-15A) (PSA: Adsorption - 5B, 9B; Desorption - 5A, 9A) As shown in Figure 5, at a certain time, in the gas separation and recovery apparatus 51 of this embodiment, the other third adsorption tower 15B of the third gas separation apparatus 14 is performing an adsorption process (third separation process), while the other third adsorption tower 15A is performing a desorption process (third regeneration process). This allows the raw material gas G1, from which butyraldehyde (the fourth component) has been removed and discharged from the other third adsorption tower 15B, to be introduced into the first gas separation device 2. In addition, the off-gas discharged from the other third adsorption tower 15A to the off-gas discharge path L5 is separated by the gas-liquid separator 60 into a gas containing butyraldehyde (the fourth component) and carbon dioxide (the third component). Butyraldehyde (the fourth component) is returned to the manufacturing facility 52 via the aldehyde recovery route L2. The gas-off gas G8, which contains carbon dioxide (third component), is supplied to the combustion equipment 54 via the exhaust path L6 and the fuel supply path 55.

[0117] Furthermore, in the first gas separation apparatus 2, the other first adsorption tower 5B performs the adsorption process (first separation process), while the other first adsorption tower 5A performs the desorption process (first regeneration process). This allows the treated gas G3, from which carbon dioxide (third component) has been removed and discharged from the other first adsorption tower 5B, to be introduced into the second gas separator 3. In addition, the regenerated gas G4, which contains carbon dioxide (third component) and is discharged from the other first adsorption tower 5A into the regenerated gas introduction path L4, can be introduced into the third gas separator 14.

[0118] Furthermore, in the second gas separation apparatus 3, the other second adsorption tower 9B performs the adsorption process (second separation process), while the other second adsorption tower 9A performs the desorption process (second regeneration process). As a result, the gas containing propane (first component) discharged from the other second adsorption tower 9B can be supplied to the combustion equipment 54 as first component gas G5 via the first component discharge route L7 and the fuel supply route 55. In addition, a portion of the gas containing propane (first component) discharged from the other second adsorption tower 9B can be introduced to the first gas separation device 2 as regenerated gas G2. Furthermore, the propylene (second component) discharged from the second adsorption tower 9A to the second component discharge pipe 10i can be supplied to the manufacturing equipment 52 via the return route 53.

[0119] (PSA: Adsorption - 5A, Depressurization - 9B, Pressure Equalization - 5B, 9A) Next, Figure 6 shows the state in which, starting from the state shown in Figure 5, one of the first adsorption towers 5A in the first gas separation apparatus 2 is switched from the desorption process (first regeneration process) to the adsorption process (first separation process), the other second adsorption tower 9B in the second gas separation apparatus 3 is switched from the adsorption process (second separation process) to the depressurization process, and a pressure equalization process is performed between the other first adsorption tower 5B in the first gas separation apparatus 2 and one of the adsorption towers 9A in the second gas separation apparatus 3.

[0120] In the first gas separation apparatus 2, one first adsorption tower 5A performs the adsorption process (first separation process), while the other first adsorption tower 5B performs the pressure equalization process. As a result, in the first adsorption tower 5A where the adsorption process (first separation process) has started, the raw material gas G1 is introduced into the first adsorption tower 5A, the pressure inside the first adsorption tower 5A increases, and carbon dioxide (third component) is adsorbed onto the adsorbent S1. Furthermore, in the other first adsorption tower 5B where the pressure equalization process has started, the pressure inside the other first adsorption tower 5B is depressurized, and the gas containing propylene (second component) and propane (first component) that is discharged from the first adsorption tower 5B is discharged to the pressure equalization gas path 4 as pressure equalization gas G7.

[0121] Furthermore, in the second gas separation apparatus 3, the other second adsorption tower 9B performs a depressurization process, while the other second adsorption tower 9A performs a pressure equalization process. As a result, in the other second adsorption tower 9B where the depressurization process has started, the pressure inside the other second adsorption tower 9B, which is under pressure, is released, thereby depressurizing the other second adsorption tower 9B. At this time, the propane (first component) remaining in the other second adsorption tower 9B is drawn out from inside the other second adsorption tower 9B, so the removal rate of unwanted components (propane) contained in the propylene (second component) obtained in the desorption process (second regeneration process) can be improved. Furthermore, in the second adsorption tower 9A, where the pressure equalization process has started, the propane (first component) and propylene (second component) remaining in the other first adsorption tower 5B can be introduced into the second adsorption tower 9A and recovered, thereby improving the recovery rate of propylene (second component).

[0122] (PSA: Adsorption - 5A, 9A; Desorption - 5B, 9B) Next, Figure 7 shows the state after switching the other first adsorption tower 5B in the first gas separation apparatus 2 from the equalization process to the desorption process (first regeneration process), and switching one of the second adsorption towers 9A in the second gas separation apparatus 3 from the equalization process to the adsorption process (second separation process), and switching the other second adsorption tower 9B from the depressurization process to the desorption process (second regeneration process).

[0123] In the first gas separation apparatus 2, one first adsorption tower 5A performs the adsorption process (first separation process), while the other first adsorption tower 5B performs the desorption process (first regeneration process). This allows the treated gas G3, from which carbon dioxide (the third component) has been removed and discharged from the first adsorption tower 5A, to be introduced into the second gas separator 3. Furthermore, the regenerated gas G4, containing carbon dioxide (the third component), which has been discharged from the other first adsorption tower 5B into the regenerated gas introduction path L4, can be introduced into the third gas separator 14.

[0124] Furthermore, in the second gas separation apparatus 3, one second adsorption tower 9A performs the adsorption process (second separation process), while the other second adsorption tower 9B performs the desorption process (second regeneration process). As a result, the gas containing propane (first component) discharged from one of the second adsorption towers 9A can be supplied to the combustion equipment 54 as first component gas G5 via the first component discharge route L7 and the fuel supply route 55. In addition, a portion of the gas containing propane (first component) discharged from one of the second adsorption towers 9A can be introduced to the first gas separation device 2 as regenerated gas G2. Furthermore, the propylene (second component) discharged from the other second adsorption tower 9B to the second component discharge pipe 10i can be supplied to the manufacturing equipment 52 via the return route 53.

[0125] (PSA: Adsorption-5B, Depressurization-9A, Pressure Equalization-5A,9B) Next, Figure 8 shows the state in which, starting from the state shown in Figure 7, the other first adsorption tower 5B in the first gas separation apparatus 2 is switched from the desorption process (first regeneration process) to the adsorption process (first separation process), one of the second adsorption towers 9A in the second gas separation apparatus 3 is switched from the adsorption process (second separation process) to the depressurization process, and a pressure equalization process is performed between one of the first adsorption towers 5A in the first gas separation apparatus 2 and the other adsorption tower 9B in the second gas separation apparatus 3.

[0126] In the first gas separation apparatus 2, the other first adsorption tower 5B performs the adsorption process (first separation process), while the other first adsorption tower 5A performs the pressure equalization process. As a result, in the other first adsorption tower 5B where the adsorption process (first separation process) has started, the raw material gas G1 is introduced into the other first adsorption tower 5B, the pressure inside the first adsorption tower 5B increases, and carbon dioxide (third component) is adsorbed onto the adsorbent S1. Furthermore, in the first adsorption tower 5A where the pressure equalization process has started, the pressure inside the first adsorption tower 5A is depressurized, and the gas containing propylene (second component) and propane (first component) that is discharged from the first adsorption tower 5A is discharged as pressure equalization gas G7 to the pressure equalization gas path 4.

[0127] Furthermore, in the second gas separation apparatus 3, one second adsorption tower 9A performs a depressurization process, while the other second adsorption tower 9B performs a pressure equalization process. As a result, in the second adsorption tower 9A where the depressurization process has started, the pressure inside the pressurized second adsorption tower 9A is released, thereby depressurizing the second second adsorption tower 9A. At this time, the propane (first component) remaining in the first second adsorption tower 9A is released from within the second second adsorption tower 9A, thereby improving the removal rate of unwanted components (propane) contained in the propylene (second component) obtained in the desorption process (second regeneration process). Furthermore, in the second adsorption tower 9B, where the pressure equalization process has started, the propane (first component) and propylene (second component) remaining in the first adsorption tower 5A can be introduced into the second adsorption tower 9B and recovered, thereby improving the recovery rate of propylene (second component).

[0128] As described above, in the gas separation and recovery apparatus 51 and gas separation and recovery method of this embodiment, similar to the first embodiment described above, the first adsorption towers (5A, 5B) after the first separation process and before the first regeneration process are connected to the second adsorption towers (9A, 9B) after the second regeneration process and before the second separation process, and a pressure equalization process is performed to equalize the pressure between the first adsorption towers and the second adsorption towers. This makes it possible to improve the recovery rate when separating and recovering the required components from a target gas containing multiple components.

[0129] In the gas separation and recovery system 50 of the second embodiment, even when the manufacturing facility 52 is an oxo alcohol plant and propylene is used as a raw material to produce butyraldehyde, an intermediate product, an equalization process is performed to equalize the pressure between the first adsorption tower and the second adsorption tower. This improves the recovery rate of butyraldehyde (the fourth component), which is the product, and propylene (the second component), which is the raw material, from the target gas containing butyraldehyde, carbon dioxide, propane, and propylene.

[0130] Furthermore, in the gas separation and recovery system 50 and gas separation and recovery method of the second embodiment, when switching from the first component recovery process (second separation process) to the second component recovery process (second regeneration process) described above, a depressurization process is provided to release the pressure inside the pressurized second adsorption towers 9A and 9B, thereby improving the removal rate of unwanted components (propane) contained in the propylene (second component) obtained in the second component recovery process (second regeneration process).

[0131] It should be noted that the present invention is not necessarily limited to the embodiments described above, and various modifications can be made without departing from the spirit of the invention. Specifically, the gas separation and recovery apparatus 1.51 described above is configured with a pair (two) first adsorption towers 5A and 5B and a pair (two) second adsorption towers 9A and 9B, but it is not necessarily limited to this configuration. For example, although the recovery efficiency of the second component (propylene) is reduced, it is also possible to have a configuration with one first adsorption tower and one second adsorption tower.

[0132] Furthermore, to improve the recovery efficiency of the second component (propylene), it is possible to increase the number of first or second adsorption towers to three or more. In this case, by sequentially switching the adsorption process (first separation process), pressure equalization process, and desorption process (first regeneration process) between multiple first adsorption towers, and sequentially switching the adsorption process (second separation process), depressurization process, desorption process (second regeneration process), and pressure equalization process between multiple second adsorption towers, it is possible to continuously and efficiently recover propylene (second component).

[0133] Furthermore, while the gas separation and recovery system 50 described above illustrates the use of a third gas separation device 14 that removes butyraldehyde (the fourth component) from the exhaust gas using the temperature swing method (TSA), it is also possible to use a separation device that removes butyraldehyde (the fourth component) from the exhaust gas by other methods. For example, methods for removing butyraldehyde (the fourth component) include the cooling liquefaction method and the liquid absorption method. [Examples]

[0134] The effects of the present invention will be made clearer by the following examples. However, the present invention is not limited to the following examples and can be modified as appropriate without altering its essence.

[0135] (Example 1) In Example 1, the gas separation and recovery system 50 described above was used to separate and recover butyraldehyde and propylene from exhaust gas discharged from the manufacturing facility 52, which is an oxo alcohol process plant. The pressure equalization process was performed between the first adsorption tower of the first gas separation device 2 and the second adsorption tower of the second gas separation device 3. The operating conditions of the gas separation and recovery system 50 were as follows.

[0136] • Exhaust gas: Of 100%, butyraldehyde: 5.7%, carbon dioxide: 20.1%, propylene: 18.9%, propane: 42.5%, other: 16.7% (Third gas separation unit: TSA) • Adsorbent S3: Granular Shirasagi activated carbon manufactured by Osaka Gas Chemical Co., Ltd. • Heating temperature of adsorbent S3: 175℃ • Adsorption process (third separation process) time: 8 hours • Desorption process (third regeneration process) time: 8 hours (First gas separation unit: PSA) • Adsorbent S1: Manufactured by Osaka Gas Chemical Co., Ltd., Molcebon • Pressure inside the first adsorption towers 5A and 5B: 500 kPaG during adsorption, 101.3 kPaA during desorption. • Time for the adsorption process (first separation process): 180 seconds • Pressure equalization process time: 5 seconds • Desorption process (first regeneration process) time: 175 seconds (Second gas separation unit: PSA) • Adsorbent S2: Manufactured by Osaka Gas Chemical Co., Ltd., Molcebon • Pressure inside the second adsorption towers 9A and 9B: 475 kPaG during adsorption, 10 kPaA during desorption • Adsorption process (second separation process) time: 175 seconds • Depressurization process time: 2 seconds • Desorption process (second regeneration process) time: 175 seconds • Pressure equalization process time: 5 seconds

[0137] As a result, in Example 1, butyraldehyde with a concentration of 95% and propylene with a concentration of 41% were obtained. Furthermore, the recovery rate of butyraldehyde was 85%, and the recovery rate of propylene was 84%.

[0138] (Comparative Example 1) In Comparative Example 1, in the gas separation and recovery system 50 described above, the pressure equalization process was not performed between the first adsorption tower of the first gas separation device 2 and the second adsorption tower of the second gas separation device 3, but rather between the first adsorption towers 5A and 5B of the first gas separation device 2 and between the second adsorption towers 9A and 9B of the second gas separation device 3. The operating conditions were as follows.

[0139] • Exhaust gas: Of 100%, butyraldehyde: 5.7%, carbon dioxide: 20.1%, propylene: 18.9%, propane: 42.5%, other: 16.7% (Third gas separation unit: TSA) • Adsorbent S3: Granular Shirasagi activated carbon manufactured by Osaka Gas Chemical Co., Ltd. • Heating temperature of adsorbent S3: 175℃ • Adsorption process (third separation process) time: 8 hours • Desorption process (third regeneration process) time: 8 hours (First gas separation unit: PSA) • Adsorbent S1: Manufactured by Osaka Gas Chemical Co., Ltd., Molcebon • Pressure inside the first adsorption towers 5A and 5B: 500 kPaG during adsorption, 101.3 kPaA during desorption. • Time for the adsorption process (first separation process): 175 seconds • Pressure equalization process time: 5 seconds • Desorption process (first regeneration process) time: 175 seconds (Second gas separation unit: PSA) • Adsorbent S2: Manufactured by Osaka Gas Chemical Co., Ltd., Molcebon • Pressure inside the second adsorption towers 9A and 9B: 475 kPaG during adsorption, 10 kPaA during desorption • Adsorption process (second separation process) time: 175 seconds • Depressurization process time: 2 seconds • Desorption process (second regeneration process) time: 173 seconds • Pressure equalization process time: 5 seconds

[0140] As a result, in Comparative Example 1, butyraldehyde with a concentration of 95% and propylene with a concentration of 37% were obtained. Furthermore, the recovery rate of butyraldehyde was 85%, and the recovery rate of propylene was 71%.

[0141] From the above, it has become clear that high-purity propylene can be efficiently recovered from exhaust gas containing four components by performing a pressure equalization process between the first adsorption tower of the first gas separation device 2 and the second adsorption tower of the second gas separation device 3.

[0142] <Verification Test 1> In Example 1 and Comparative Example 1 described above, the propylene recovery rate was compared when a pressure equalization process was performed between the first adsorption tower of the first gas separation apparatus 2 and the second adsorption tower of the second gas separation apparatus 3. The results are shown in Table 1 below.

[0143] [Table 1]

[0144] As shown in Table 1, when the pressure equalization process is performed between the first adsorption tower of the first gas separator 2 and the second adsorption tower of the second gas separator 3, it was confirmed that the propylene recovery rate improved by 13-18% compared to the conventional method of performing the process between the first adsorption towers 5A and 5B of the first gas separator 2 and between the second adsorption towers 9A and 9B of the second gas separator 3.

[0145] <Verification Test 2> In the above-described Example 1, the effect of including a depressurization step in the operating cycle of the second adsorption towers 9A and 9B of the second gas separation apparatus 3 was investigated. The results are shown in Table 2 below.

[0146] [Table 2]

[0147] As shown in Table 2, by adding a depressurization step to the operating cycle of the second adsorption towers 9A and 9B of the second gas separation unit 3, it was confirmed that the removal rate of unwanted components (propane, carbon dioxide) improved by 10-22.5%, although this resulted in fluctuations in the propylene recovery rate, compared to the case without the depressurization step. [Explanation of Symbols]

[0148] 1.51 Gas Separation and Recovery System 2. First gas separation unit 3. Second gas separation unit 4. Gas path for pressure equalization (gas path) 5A,5B 1st adsorption tower 9A,9B 2nd adsorption tower 14. Third Gas Separation Unit 50 Gas Separation and Recovery System 52. Manufacturing facilities (oxo alcohol plant) 53 Return Route 54 Combustion equipment 55 Fuel supply routes

Claims

1. A gas separation and recovery apparatus for separating and recovering a required one component, which is at least one of the first and second components, from a target gas containing at least three components, A first gas separation apparatus having a first adsorption tower that separates a third component from the target gas by a pressure fluctuation adsorption method, A second gas separation apparatus is provided, which is located on the secondary side of the first gas separation apparatus and has a second adsorption tower that separates the second component and the first component from the target gas by a pressure fluctuation adsorption method. It comprises a gas path located between the first gas separation device and the second gas separation device, and connecting the first adsorption tower and the second adsorption tower, A gas separation and recovery apparatus in which the gas path connects the first adsorption tower (after adsorption and before regeneration) and the second adsorption tower (after regeneration and before adsorption) and is used for pressure equalization.

2. The gas separation and recovery apparatus according to claim 1, wherein the gas path connects the first adsorption tower, which has adsorbed the third component onto the adsorbent and before the adsorbent has been regenerated, and the second adsorption tower, which has adsorbed the second component onto the adsorbent and before the second component has been adsorbed onto the adsorbent, and is used for equalizing pressure.

3. The gas separation and recovery apparatus according to claim 1, wherein the gas path connects the first adsorption tower (after adsorption and before regeneration) and the second adsorption tower (after regeneration and before adsorption) and is used solely for the purpose of equalizing pressure.

4. The gas separation and recovery apparatus according to claim 1, wherein one end of the gas path is connected to the upper side of the first adsorption tower, and the other end of the gas path is connected to the lower side of the second adsorption tower.

5. The gas separation and recovery apparatus according to claim 1, further comprising a third gas separation apparatus located on the primary side of the first gas separation apparatus, which removes a fourth component other than the first to third components from the target gas by a temperature fluctuation adsorption method.

6. The gas separation and recovery apparatus according to claim 5, wherein the target gas includes one or more selected from the group consisting of butyraldehyde, carbon dioxide, propane, and propylene.

7. The gas separation and recovery apparatus according to claim 1, wherein the target gas includes butyraldehyde, carbon dioxide, propane, and propylene.

8. A gas separation and recovery method for separating and recovering a required one component, which is at least one of the first and second components, from a target gas containing at least three components, A first separation step involves separating a third component from the target gas using a first adsorption tower in a first gas separation apparatus of the pressure fluctuation adsorption type, A first regeneration step of desorbing the third component from the first adsorption tower, A second separation step in which the second component is separated from the target gas by a second adsorption tower in a second gas separation apparatus of the pressure fluctuation adsorption type, A second regeneration step of desorbing the second component from the second adsorption tower, A gas separation and recovery method comprising: a pressure equalization step, which connects the first adsorption tower after the first separation step and before the first regeneration step with the second adsorption tower after the second regeneration step and before the second separation step, and equalizes the pressure between the first adsorption tower and the second adsorption tower.

9. The first adsorption tower repeatedly performs a first cycle including the first separation step, the pressure equalization step, and the first regeneration step. The second adsorption tower repeats the second cycle, which includes the pressure equalization step, the second separation step, and the second regeneration step, The gas separation and recovery method according to claim 8, wherein the first adsorption tower and the second adsorption tower are synchronized so that they perform the pressure equalization process simultaneously.

10. The gas separation and recovery method according to claim 8 or 9, wherein the target gas comprises butyraldehyde, carbon dioxide, propane, and propylene.

11. A gas separation and recovery system for separating and recovering a required one component, which is at least one of the first and second components, from a target gas containing at least three components, A manufacturing facility that discharges the aforementioned target gas as exhaust gas, A gas separation and recovery apparatus according to any one of claims 1 to 7, A gas separation and recovery system comprising a return route for returning at least one of the first component and the second component recovered by the gas separation and recovery device to the manufacturing equipment.

12. Combustion equipment that burns gaseous components as fuel, The gas separation and recovery system according to claim 11, further comprising a fuel supply path for supplying gas components other than the first to third components separated by the gas separation and recovery device to the combustion equipment.

13. The gas separation and recovery system according to claim 11 or 12, wherein the manufacturing equipment is equipment for performing an oxo alcohol process.

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