JP2020018988A - Pressure swing adsorption device - Google Patents

Abstract

To reduce exhaust sound when an adsorption unit including multiple adsorption tanks performs a depressurizing step.SOLUTION: A control unit 20, when performing a depressurizing step with an adsorption unit 1A, controls primary-side selector valves 18b, 18c to start discharging a second enriched gas from adsorption tanks 2a/2b constituting the adsorption unit 1A, and then to start discharging the second enriched gas from other adsorption tanks 2b/2c constituting the adsorption unit 1A.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a pressure swing adsorption apparatus for separating a source gas containing at least two kinds of gases by a pressure swing adsorption method.

  A pressure swing adsorption apparatus (hereinafter, PSA apparatus) separates a source gas containing at least two kinds of gases by a pressure swing adsorption method.

  The PSA device includes an adsorption tank filled with an adsorbent. The PSA apparatus performs a pressurizing step of supplying a raw material gas to an adsorption tank to pressurize the adsorption tank, and adsorbing a specific gas contained in the raw material gas to an adsorbent to obtain a product gas. Further, the PSA apparatus performs a depressurizing step of depressurizing the pressurized adsorption tank and desorbing the specific gas from the adsorbent to obtain exhaust gas.

  For example, in the PSA apparatus of Patent Document 1, an adsorption unit is configured by a plurality of adsorption tanks, a plurality of the adsorption units are provided, and a pressurizing step and a depressurizing step can be performed alternately for each adsorption unit.

Japanese Patent No. 3623152

  In the PSA device of Patent Literature 1, when a depressurization step is performed in a certain adsorption unit, exhaust gas starts to be discharged from all the adsorption tanks in the adsorption unit all at once. Therefore, it is inevitable that loud exhaust noise is generated. This exhaust noise increases in accordance with the number of suction tanks constituting the suction unit.

  An object of the present invention is to provide a pressure swing adsorption apparatus that can control exhaust from an adsorption tank so as to reduce exhaust noise when performing a depressurization step in an adsorption unit including a plurality of adsorption tanks. And

The present invention provides a method for converting a source gas containing a first gas and a second gas into a first enriched gas containing the concentrated first gas and a second enriched gas containing the concentrated second gas. A pressure swing adsorption device that separates by a pressure swing adsorption method,
At least one adsorption unit including a plurality of adsorption tanks arranged in parallel with each other and including an adsorbent that preferentially adsorbs the second gas to the first gas;
In order to supply the source gas to each of the adsorption tanks, a source gas line communicating with the primary side of each of the adsorption tanks,
A first gas line communicating with a secondary side of each of the adsorption tanks to discharge the first enriched gas from each of the adsorption tanks;
A second gas line that communicates with a primary side of each of the adsorption tanks to discharge the second enriched gas from each of the adsorption tanks;
A source gas valve for opening and closing the source gas line,
A second gas valve for opening and closing the second gas line;
A primary side switching valve provided for at least one of the adsorption tanks of the adsorption unit, for switching communication between a primary side of the corresponding adsorption tank and the second gas line;
A control unit that controls the primary-side switching valve,
The source gas is supplied from the source gas line to the adsorption tank, the inside of the adsorption tank is pressurized, and the second gas is adsorbed on the adsorbent to obtain the first enriched gas, and the first enriched gas is obtained. Pressurizing step of discharging a chemical gas from the adsorption tank to the first gas line;
The pressurized adsorption tank is depressurized and the second gas is desorbed from the adsorbent to obtain the second enriched gas, and the second enriched gas is discharged from the adsorption tank to the second gas line. And a depressurization step of discharging to
When the depressurization step is performed in the adsorption unit, the control unit controls the primary-side switching valve to start discharging the second enriched gas from the adsorption tank including the adsorption unit. Later, it is started to be discharged from another suction tank of the suction unit.

Preferably, at least one secondary side is provided for the adsorption tank provided with the primary side switching valve and switches communication between a corresponding secondary side of the adsorption tank and the first gas line. Further provided with a switching valve,
The number of the adsorption tanks used when performing the pressurizing step and the depressurizing step is configured to be selectable.

Preferably, a plurality of the suction units are provided,
The pressurizing step and the depressurizing step can be performed for each of the suction units.

  According to the present invention, there is provided a PSA apparatus capable of controlling exhaust from an adsorption tank so that exhaust noise is reduced when a depressurization step is performed in an adsorption unit including a plurality of adsorption tanks.

FIG. 1 is a schematic diagram of one embodiment of a PSA device according to the present invention. FIG. 2 is a diagram illustrating the operation of the PSA device of FIG. FIG. 2 is a diagram illustrating the operation of the PSA device of FIG. FIG. 2 is a diagram illustrating the operation of the PSA device of FIG.

  Hereinafter, a pressure swing adsorption device (hereinafter, PSA device) according to the present invention will be described with reference to the drawings. FIG. 1 schematically shows a PSA device.

  The PSA device converts a source gas containing at least a first gas and a second gas into a first enriched gas containing a concentrated first gas and a second enriched gas containing a concentrated second gas. Separate by method.

  The PSA device includes a plurality (two in the embodiment) of suction units 1A and 1B. Each of the suction units 1A and 1B includes a plurality (three in the embodiment) of suction tanks 2a, 2b, and 2c arranged in parallel with each other. Each of the adsorption tanks 2a, 2b, and 2c includes an adsorbent (not shown) therein. This adsorbent has a property of adsorbing the second gas in preference to the first gas.

  When the PSA device is an oxygen PSA device using air as a source gas, an oxygen-enriched gas as a product gas (first enriched gas), and a nitrogen-enriched gas as exhaust gas (second enriched gas), For example, a zeolite adsorbent that adsorbs nitrogen gas in preference to oxygen gas is used. When the PSA device is a nitrogen PSA device using air as a source gas, a nitrogen-enriched gas as a product gas, and an oxygen-enriched gas as an exhaust gas, for example, a molecular sieve that adsorbs oxygen gas in preference to nitrogen gas is used as an adsorbent. An activated carbon adsorbent is used. When the PSA device is a clean dry air generator that uses air as a raw material gas, absorbs moisture in the air, and produces non-heated and dried air as a product gas, a desiccant is used as an adsorbent.

  The PSA apparatus further includes a source gas line 3 for supplying the source gas to each of the adsorption tanks 2a, 2b, 2c of the adsorption units 1A, 1B. The source gas line 3 communicates with the primary sides of the adsorption tanks 2a, 2b, 2c of the adsorption units 1A, 1B via primary side branch lines 4A, 4B. The PSA device is provided with a pump (not shown), and the source gas compressed by the pump is supplied to the adsorption tanks 2a, 2b, 2c of the adsorption units 1A, 1B through these lines 3, 4A, 4B. It is possible.

  The PSA device is further disposed on the source gas line 3 and further includes source gas valves 5A and 5B for opening and closing the source gas line 3. Source gas valves 5A and 5B are provided for each of the adsorption units 1A and 1B. The supply of the source gas to the corresponding adsorption units 1A, 1B is controlled by the source gas valves 5A, 5B.

  The PSA apparatus further includes a second gas line 6 for discharging the second enriched gas obtained as described later from each of the adsorption tanks 2a, 2b, 2c of the adsorption units 1A, 1B. The second gas line 6 communicates with the primary sides of the adsorption tanks 2a, 2b, 2c of the adsorption units 1A, 1B via primary side branch lines 4A, 4B. The second gas line 6 has an exhaust gas outlet for discharging the second enriched gas as an exhaust gas to the outside of the PSA device, and a silencer 7 is provided at the exhaust gas outlet.

  The PSA device is further provided with second gas valves 8A and 8B arranged on the second gas line 6 for opening and closing the second gas line 6. The second gas valves 8A and 8B are provided for each of the adsorption units 1A and 1B. The discharge of the second enriched gas from the corresponding adsorption units 1A, 1B is controlled by the second gas valves 8A, 8B.

  The PSA apparatus further includes a first gas line 9 for discharging the first enriched gas obtained as described later from each of the adsorption tanks 2a, 2b, 2c of the adsorption units 1A, 1B. The first gas line 9 communicates with the suction tanks 2a, 2b, 2c of the suction units 1A, 1B via the secondary branch lines 10A, 10B. The first gas line 9 includes a product gas port 11 for discharging the first enriched gas as a product gas to the outside of the PSA device. The first gas line 9 is provided with a product gas tank (buffer tank) 12, a pressure reducing valve 13, and a pressure gauge 14.

  The PSA device further includes check valves 15A and 15B provided for the suction units 1A and 1B, respectively. The check valves 15A and 15B are arranged in the secondary side branch lines 10A and 10B, and prevent the first enriched gas from flowing back from the first gas line 9 to the corresponding adsorption units 1A and 1B.

  The PSA device is provided with equalizing valves 16 and 17 for equalizing the pressure between the adsorption units 1A and 1B.

  The PSA device further includes primary side switching valves 18b, 18c provided for at least one (two in the embodiment) adsorption tanks 2b, 2c of each of the adsorption units 1A, 1B. The primary-side switching valves 18b and 18c are arranged in the primary-side branch lines 4A and 4B, and switch communication between the primary sides of the corresponding adsorption tanks 2b and 2c and the second gas line 6.

  The PSA device further includes secondary switching valves 19b and 19c provided for the adsorption tanks 2b and 2c provided with the primary switching valves 18b and 18c. The secondary-side switching valves 19b and 19c are arranged in the secondary-side branch lines 10A and 10B, and switch communication between the secondary sides of the corresponding adsorption tanks 2b and 2c and the first gas line 9. .

  The PSA device further includes a control unit 20 that is electrically connected to each of the valves 5A, 5B, 8A, 8B, 13, 16, 17, 18b, 18c, 19b, and 19c and controls these valves. The control unit 20 includes a control circuit and the like.

  The PSA apparatus is configured so as to be able to perform the pressurizing step and the depressurizing step for each of the adsorption units 1A and 1B by providing the above-mentioned constituent requirements.

  The pressurizing step is to supply the raw material gas to the adsorption tank and pressurize the adsorption tank so that the second gas contained in the raw material gas is adsorbed by the adsorbent to obtain the first enriched gas, In this step, the gas is discharged from the adsorption tank to the first gas line 9 as a product gas.

  The depressurization step is to depressurize the pressurized adsorption tank to desorb the second gas from the adsorbent to obtain a second enriched gas, and use the second enriched gas as an exhaust gas to discharge the second gas from the adsorption tank. This is a step of discharging to the production line 6.

  The PSA device can continuously supply the first enriched gas (product gas) by alternately performing the pressurizing step and the depressurizing step in the two adsorption units 1A and 1B.

  Further, the PSA device is provided with the primary side and secondary side switching valves 18b, 18c, 19b, 19c, so that the adsorption tanks 2a, 2b, 2c used when performing the pressurizing step and the depressurizing step are provided. The number is selectable. For example, during the pressurizing step and the depressurizing step, the first switching valve 18c and the second switching valve 19c are kept closed, so that the corresponding suction tank 2c is not used and the two suction tanks 2a and 2b are used. Can be

Hereinafter, the operation of the PSA device will be described.
The PSA apparatus performs the pressure step and the depressurization step alternately in the adsorption units 1A and 1B. FIG. 2 to FIG. 4 show that the PSA apparatus performs a depressurization step in the suction unit 1A and performs a pressurization step in the suction unit 1B. All the suction tanks 2a, 2b, 2c of the suction units 1A, 1B are used.

  Referring to FIG. 2, in the adsorption unit 1B, the compressed source gas is supplied to each of the adsorption units 2a, 2b, and 2c through the source gas line 3 and the primary side branch line 4B, and each of the adsorption tanks 2a, 2b, and 2c. Is pressurized. Then, the second gas contained in the source gas is adsorbed by the adsorbents of the adsorption units 2a, 2b, 2c. Thereby, the first enriched gas is obtained.

  When the pressure in the adsorption tanks 2a, 2b, 2c rises above the pressure in the product gas tank (buffer tank) 12, the first enriched gas (product gas) is supplied to the adsorption tanks 2a, 2b, 2c of the adsorption unit 1B. It is taken out from the secondary side, flows through the secondary side branch line 10B and the first gas line 9 to the product gas tank (buffer tank) 12, and then is discharged from the product gas port 11 to the outside of the apparatus.

  On the other hand, in the adsorption unit 1A, the pressurizing step ends, and the depressurizing step starts. The suction tanks 2a, 2b, 2c of the suction unit 1A are in a pressurized state. The source gas valve 5A is closed. First, the second gas valve 8A is opened by the control unit 20, and the adsorption tank 2a is opened to the atmospheric pressure. At this time, the primary side switching valves 18b and 18c are closed. The decompression of the adsorption tank 2a is started, and the second gas is desorbed from the adsorbent of the adsorption tank 2a. Thereby, the second enriched gas is obtained in the adsorption tank 2a.

  The second rich gas starts to be discharged from the adsorption tank 2a. The second enriched gas is discharged as exhaust gas from the adsorption tank 2a to the second gas line 6 through the primary branch line 4A, and then discharged from the silencer 7 (exhaust gas outlet) to the outside of the apparatus.

  In the adsorption unit 1A, after a lapse of a predetermined time (for example, one second) after the second gas valve 8A is opened and the second enriched gas starts to be discharged from the adsorption tank 2a, as shown in FIG. The switching valve 18b is opened by the control unit 20, and the second enriched gas starts to be discharged from the adsorption tank 2b. The second enriched gas is discharged as exhaust gas from the adsorption tank 2b to the second gas line 6 through the primary side branch line 4A, and then discharged from the silencer 7 (exhaust gas outlet) to the outside of the apparatus.

  In the adsorption unit 1A, after a lapse of a predetermined time (for example, one second) after the primary side switching valve 18b is opened and the second enriched gas starts to be discharged from the adsorption tank 2b, as shown in FIG. The valve 18c is opened by the control unit 20, and the second rich gas starts to be discharged from the adsorption tank 2c. The second enriched gas is discharged as exhaust gas from the adsorption tank 2c to the second gas line 6 through the primary side branch line 4A, and then discharged from the silencer 7 (exhaust gas outlet) to the outside of the device.

  As described above, the control unit 20 controls the sequence so that the second gas valve 8A and the primary side switching valves 18b and 18c are opened with a time difference, and the second enriched gas starts to be discharged from a certain adsorption tank 2a / 2b. After that, discharge from another adsorption tank 2b / 2c is started. The exhaust noise due to this control is reduced as compared with the exhaust noise when the second enriched gas is simultaneously discharged from all the adsorption tanks 2a, 2b, 2c. This is because the flow rate in the second gas line 6 and the silencer 7 (exhaust port) is smaller in the former than in the latter.

  Thereafter, the PSA apparatus performs the pressurizing step in the suction unit 1A, and performs the depressurizing step in the suction unit 1B by the above-described sequence control. And this is repeated.

[Example]
An oxygen PSA device having the configuration shown in FIG. 1 was prepared. The depressurizing step was performed by the adsorption unit 1A as shown in FIGS. Each of the three adsorption tanks 2a, 2b, 2c has an internal capacity of 480 L (160 L * 0.3 MPa). The valves 8A, 18b, and 18c were sequentially opened with a difference of one second, and the nitrogen-enriched gas (the second enriched gas / exhaust gas) was discharged with a difference of one second in the order of the adsorption tanks 2a, 2b, and 2c. 480 L was discharged from each of the adsorption tanks 2a, 2b, 2c in about 1 second. Therefore, in the embodiment, the displacement in the silencer 7 (exhaust gas port) is about 480 L / sec.

[Comparative example]
An oxygen PSA device similar to that of Example 1 was prepared. The contents of the suction tanks 2a, 2b, 2c are the same as in the first embodiment. In the comparative example, the valves 8A, 18b, and 18c were simultaneously opened to simultaneously discharge the nitrogen-enriched gas (the second enriched gas and exhaust gas). 480 L was discharged from each of the adsorption tanks 2a, 2b, 2c in about 1 second. Therefore, in the comparative example, the displacement in the silencer 7 (exhaust gas port) is about 1440 L / sec.

  In each of [Example] and [Comparative Example], the noise value of the exhaust noise was measured by a measuring device at a position 100 mm away from the silencer 7. The measuring instrument is manufactured by Rion Co., Ltd., model number: NA-29, S / N: 10732119. The measurement results are shown below.

  As is clear from the above table, even when the same silencer 7 is used, the example reduces the exhaust noise as compared with the comparative example. This is because the flow rate in the silencer 7 (exhaust gas port) is smaller in the example than in the comparative example.

  The PSA device itself including the primary-side switching valves 18b and 18c is conventional. As is clear from the comparison between the embodiment and the comparative example, the present invention reduces the exhaust noise without adding any hardware component to the existing PSA device by the sequence control of the primary switching valves 18b and 18c. It is very effective in that it can. That is, the reduction of the exhaust noise according to the present invention costs little.

The present invention is not limited to the above embodiment.
The PSA device is not limited to an oxygen PSA device, a nitrogen PSA device, and a clean dry air generator, but may be another PSA device.

  In the embodiment, two suction units 1A and 1B are provided, but only one suction unit may be provided. Further, three or more suction units may be provided.

  In the embodiment, each of the suction units 1A and 1B is configured by three suction tanks 2a, 2b, and 2c, but may be configured by two suction tanks, or may be configured by four or more suction tanks. Good.

  The primary side switching valve may be provided in all the adsorption tanks, but even if there is an adsorption tank 2a in which the primary side switching valve is not provided as in the embodiment, the object of the present invention can be achieved. it can.

1A, 1B Adsorption units 2a, 2b, 2c Adsorption tank 3 Source gas line 5 Source gas valve 6 Second gas line (exhaust gas line)
7 Silencer for exhaust gas port 8 Valve for second gas (valve for exhaust gas)
9 First gas line (product gas line)
11 Product gas ports 18b, 18c Primary switching valves 19b, 19c Secondary switching valves 20 Controller

Claims (3)

A source gas containing a first gas and a second gas is subjected to pressure swing adsorption by a first enriched gas containing the concentrated first gas and a second enriched gas containing the concentrated second gas. Pressure swing adsorption device separated by
At least one adsorption unit including a plurality of adsorption tanks arranged in parallel with each other and including an adsorbent that preferentially adsorbs the second gas to the first gas;
In order to supply the source gas to each of the adsorption tanks, a source gas line communicating with the primary side of each of the adsorption tanks,
A first gas line communicating with a secondary side of each of the adsorption tanks to discharge the first enriched gas from each of the adsorption tanks;
A second gas line that communicates with a primary side of each of the adsorption tanks to discharge the second enriched gas from each of the adsorption tanks;
A source gas valve for opening and closing the source gas line,
A second gas valve for opening and closing the second gas line;
A primary side switching valve provided for at least one of the adsorption tanks of the adsorption unit, for switching communication between a primary side of the corresponding adsorption tank and the second gas line;
A control unit that controls the primary-side switching valve,
The source gas is supplied from the source gas line to the adsorption tank, the inside of the adsorption tank is pressurized, and the second gas is adsorbed on the adsorbent to obtain the first enriched gas, and the first enriched gas is obtained. Pressurizing step of discharging a chemical gas from the adsorption tank to the first gas line;
The pressurized adsorption tank is depressurized and the second gas is desorbed from the adsorbent to obtain the second enriched gas, and the second enriched gas is supplied from the adsorption tank to the second gas line. And a depressurization step of discharging to
When the depressurization step is performed in the adsorption unit, the control unit controls the primary-side switching valve to start discharging the second enriched gas from the adsorption tank including the adsorption unit. Later, to start discharging from another adsorption tank of the adsorption unit,
A pressure swing adsorption device, characterized in that: At least one secondary switching valve provided for the adsorption tank provided with the primary switching valve and for switching communication between the secondary side of the corresponding adsorption tank and the first gas line. , More prepared,
The number of the adsorption tank used when performing the pressurizing step and the depressurizing step is configured to be selectable,
The pressure swing adsorption device according to claim 1, wherein: A plurality of the suction units are provided,
The pressurizing step and the depressurizing step are configured to be executable for each of the suction units,
The pressure swing adsorption device according to claim 1 or 2, wherein:

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