JP2018043186A - Gas separation equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide gas separation equipment in which useless power consumption is suppressed by avoiding exhaustion of compressed air in a pressure equalization process time.SOLUTION: The gas separation equipment is provided that comprises: a compressor for compressing air; an air tank for storing the compressed air; pressure detection means for detecting pressure of the air tank; a plurality of adsorption tanks each of which is filled with an adsorbent inside, separates one gas among compressed air supplied from the air tank and separates the other gas as product gas; and a control part for controlling operation-stopping of a compressor body and a gas separation process in the adsorption tank. The control part controls the compressor in such a manner that the compressor maintains normal operation in a pressure equalization process time for communicating the plurality of adsorption tanks with each other.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a gas separation device.

  There exists patent document 1 as a background of this technical field. Patent Document 1 describes a gas separation device that closes the exhaust valve 15 and unloads the compressor 13 when the adsorption tanks 23 and 24 are in a pressure equalization process.

JP-A-9-24231

  According to Patent Document 1, the supply of compressed air from the compressor can be continuously received during the adsorption process, but the compressed air produced by the compressor is exhausted during the pressure equalization process, so that the compressor is operated accordingly. The necessary power is wasted. In addition, a mechanism for exhausting is required.

  It is an object of the present invention to provide a gas separation device that suppresses wasteful power consumption without exhausting compressed air during the pressure equalization step.

  In order to solve the above problems, the present invention provides a compressor for compressing air, an air tank for storing compressed air, a pressure detection means for detecting the pressure of the air tank, and an adsorbent inside. A plurality of adsorption tanks for separating one gas from the compressed air supplied from the air tank and separating the other gas as a product gas; operation and stop of the compressor body; and a gas separation step in the adsorption tank And a control unit that controls the compressor so that the compressor maintains normal operation during a pressure equalization step that allows the plurality of adsorption tanks to communicate with each other. Providing the device.

  ADVANTAGE OF THE INVENTION According to this invention, the gas separation apparatus which suppressed wasteful power consumption can be provided, without exhausting compressed air at the time of a pressure equalization process.

It is a whole block diagram which shows the gas separation apparatus in Example 1 of this invention. It is a figure which shows each process of the gas separation apparatus in Example 1 of this invention. It is a graph which shows the pressure change of the air tank and adsorption tank in a prior art example. It is a graph which shows the pressure change of the air tank and adsorption tank in Example 1 of this invention. It is a figure which shows each process of the gas separation apparatus in Example 2 of this invention.

  A first embodiment of the present invention will be described with reference to FIG. The whole structure of the gas separation apparatus in a present Example is demonstrated using FIG.

A gas separation device 1 shown in FIG. 1 is a PSA type gas separation device. The gas separation device 1 includes an air supply unit 2 that supplies air and a PSA unit 3 that generates product gas.
In the present embodiment, as an example, the air supply unit 2 and the PSA unit 3 are stored separately in separate housings, but the two units may be stored in the same housing.

  The air supply unit includes a compressor 4 that compresses air, an electric motor (not shown) that drives the compressor 4, an air tank 5 that stores compressed air, and pressure detection means 8 that detects the pressure of the air tank 5. And an air dryer 6 for dehumidifying the compressed air, and a drain filter 7 for removing impurities while collecting the drain water deposited. The compressor 4 outputs a detection signal from the pressure detection means 8 to the control unit 60, and the operation is controlled by the operation pressure and the control pressure set by the control unit 60. That is, the compressor 4 starts normal operation when the pressure in the air tank 5 becomes equal to or lower than the operation pressure. When the pressure in the air tank 5 rises from the operating pressure and becomes equal to or higher than the control pressure, the compressor 4 is controlled so as to change from the normal operation state to the stop state or the unload operation state. When the control pressure is reached, the normal operation state of the compressor 4 may be maintained and the air in the air tank 5 may be exhausted. In the present embodiment, as an example, the compressor 4, the air tank 5, the air dryer 6, and the drain filter 7 are stored in a casing. On the other hand, the PSA unit 3 separates a predetermined gas from the compressed air supplied from the air supply unit 2, thereby generating adsorption tanks 19 a and 19 b that generate product gas, and a nitrogen tank that stores product gas (nitrogen). Product gas storage tank) 41.

  The compressed air stored in the air tank 5 is supplied to adsorption tanks 19 a and 19 b described later, and a predetermined gas is separated from the compressed air stored in the air tank 5. In the present embodiment, a case where nitrogen is separated by adsorbing oxygen in the adsorption tanks 19a and 19b will be described. However, oxygen may be separated by adsorbing nitrogen, or other air may be separated from compressed air other than the atmosphere. The gas may be separated. In the present embodiment, the gas separation device is constituted by the two adsorption tanks 19a and 19b. However, the gas separation apparatus may be constituted by three or more adsorption tanks.

  As the compressor 4, a double-acting type, screw type or scroll type compressor, a booster compressor for supplying a primary pressure from the outside and recompressing the compressor, or the like is used.

  A pipe 16 through which compressed air from the air tank 5 flows is connected to the air tank 5, and pipes 17 a and 17 b branched into two systems are connected to the terminal position of the pipe 16. Supply pipes 18a and 18b for opening and closing the flow paths are provided in the middle of the pipes 17a and 17b, respectively, and adsorption tanks 19a and 19b for adsorbing oxygen molecules and taking out nitrogen gas as product gas are respectively connected. ing. This adsorption tank has a constant volume. The pipes 17a and 17b are connected to pipes 21a and 21b at positions between the supply valves 18a and 18b and the adsorption tanks 19a and 19b, respectively. Exhaust valves 22a and 22b are provided with an exhaust silencer 23 with a filter for silencing at the terminal. This exhaust silencer may be provided for each of the adsorption tanks 19a and 19b. Pipes 25a and 25b are connected to the pipes 17a and 17b so as to connect the positions between the pipes 21a and 21b and the adsorption tanks 19a and 19b. Lower pressure equalizing valves 26a and 26b are provided.

  The adsorption tanks 19a and 19b are filled with, for example, an adsorbent that is an adsorbing means for adsorbing oxygen molecules. Specifically, molecular sieve carbon or zeolite is used as the adsorbent. Pipes 31a and 31b that join each other are connected to the adsorption tanks 19a and 19b, respectively. Pipes 32a and 32b are connected to the pipes 31a and 31b so as to connect the adsorption tanks 19a and 19b to each other, and a throttle 33 is provided in the pipes 32a and 32b. Further, pipes 35a and 35b are connected to the pipes 31a and 31b, and upper pressure equalizing valves 36a and 36b for opening and closing the flow paths are provided in the pipes 35a and 35b. The pipes 31a and 31b are provided with take-off valves 38a and 38b for opening and closing the flow paths on the opposite side of the adsorption tanks 19a and 19b from the pipes 35a and 35b, respectively. A pipe 40 is connected to the joining position of the pipes 31a and 31b, and a nitrogen tank 41 as a product gas storage tank for storing nitrogen gas is connected to the pipe 40. A pipe 43 provided with a discharge port 42 is connected to the nitrogen tank 41, and a filter that removes dust and the like and adjusts the gas pressure in order from the nitrogen tank 41 side in the middle of the pipe 43. A regulator 44, a discharge valve 45 for opening and closing the flow path, a flow rate adjusting valve 46 for adjusting the flow rate of the product gas, and a flow rate sensor 61 for sensing the flow rate of the product gas are provided. Moreover, what is necessary is just to comprise the flow sensor 61 as needed. A pipe 48 and a pipe 49 are connected to the pipe 43 between the filter regulator 44 and the discharge valve 45. The pipe 48 has an opening / closing valve 50 for opening and closing the flow path in order from the pipe 43 side, A flow rate adjusting valve 51 for adjusting the flow rate and a silencer 52 are provided. The pipe 49 is provided with an open / close valve 54 that opens and closes the flow path, a flow rate adjustment valve 55 that adjusts the flow rate of gas, and an oxygen sensor 56 that detects the oxygen concentration in order from the pipe 43 side. The oxygen sensor 56 and the flow sensor 61 are communicably connected to the control unit 60 and output detection signals to the control unit 60. The control unit 60 receives the detection signal and controls the generation of nitrogen gas in the adsorption tanks 19a and 19b.

  Specifically, the supply valves 18a and 18b, the exhaust valves 22a and 22b, the lower pressure equalizing valves 26a and 26b, the upper pressure equalizing valves 36a and 36b, the take-off valves 38a and 38b, the discharge valve 45, and the on-off valves 50 and 54 are controlled by a control unit. 60 is communicably connected, and operates in response to a command from the control unit 60.

  Up to now, the configuration of the gas separation device 1 has been described. Here, a gas separation method performed in the gas separation device will be described.

  In the gas separation device 1, the compression process of compressing air by the compressor 4, the storage process of storing the air compressed by the compression process in the air tank 5, the dehumidification process of dehumidifying the compressed air by the air dryer 6, and dehumidification by the dehumidification process A separation step for separating the gas from the air is performed.

  In the separation step of the gas separation device 1, the following steps (a) to (d) are sequentially repeated as shown in FIG.

  (A) Adsorption / refluxing process: The compressed air compressed by the compressor 4 and stored in the air tank 5 is supplied to the adsorption tank 19 filled with the adsorbent by opening the supply valve 18, and the nitrogen tank 41. A step of recirculating the nitrogen gas remaining therein to the adsorption tank 19 by opening the extraction valve 38 to increase the pressure in the adsorption tank 19 and adsorbing oxygen molecules to the adsorbent using the pressure.

  (B) Extraction process: Continuing from the adsorption process, the compressed air is continuously supplied from the air tank 5 to the adsorption tank 19, and at the same time, the nitrogen gas separated and generated by the adsorbent is extracted from the adsorption tank 19 and stored in the nitrogen tank 41. Process.

  (C) Pressure equalization step: By opening the upper pressure equalization valve 36 and the lower pressure equalization valve 26, the pair of adsorption tanks 19 after the take-out step is communicated to equalize the pressure, thereby increasing the adsorption efficiency of the next adsorption step. And a process for generating higher purity nitrogen gas.

  (D) Regeneration step: A step of regenerating the adsorbent by desorbing oxygen molecules adsorbed by the adsorbent through the pipe 21 by opening the exhaust valve 22 in the adsorption tank 19 after completion of the pressure equalization step. . In this regeneration step, the supply valve 18, the lower pressure equalizing valve 26, the upper pressure equalizing valve 36 and the take-off valve 38 related to the adsorption tank 19 other than the exhaust valve 22 are closed.

  As shown by (1) and (2) in FIG. 2, the adsorption tank 19b performs the regeneration process (process (d)) while the adsorption process and the removal process (process (a) and (b)) are performed in the adsorption tank 19a. ) Is performed. After that, as shown in FIG. 2 (3), (c) pressure equalization step is performed simultaneously, and the adsorption tanks 19a and 19b are replaced and the adsorption step / removal step (steps (a) and (b)) and the regeneration step (step). (D)) is performed.

  The time of said adsorption | suction process (a), extraction process (b), and pressure equalization process (c) is collectively called cycle time.

  In FIG. 3, the graph of the pressure change of the air tank 5 and adsorption tank 19a, 19b in a prior art example is shown. Since the air supply valve 18 to the adsorption tank 19 is closed during the pressure equalization process, the pressure in the air tank 5 increases rapidly. At this time, if the pressure in the air tank 5 reaches a predetermined control pressure P1 at which the compressor is unloaded or stopped, the compressor 4 stops. At this time, when switching to the adsorption process, which is the next process of the pressure equalization process, it takes time to restore the pressure by operating the compressor. Therefore, the pressure in the air tank 5 decreases while the pressure is restored, leading to a decrease in the pressure and concentration of the product gas in the next adsorption step.

  Conventionally, compressed air is sometimes exhausted by an exhaust valve in order to avoid unloading or stopping the compressor 4. However, this was wasted energy.

  In FIG. 4, the graph of the pressure change of the air tank 5 and adsorption tank 19a, 19b in a present Example is shown. In this embodiment, the control pressure threshold of the compressor 4 is increased from P1 to P2 as shown in FIG. 4 during the pressure equalization process. This prevents the compressor 4 from being unloaded and stopped if the supply valve 18 during the pressure equalization step is closed and the pressure in the air tank 5 rises to become P1 or more and is P2 or less. It becomes easy to maintain the normal operation state of the compressor 4. Further, it is not necessary to exhaust the compressed air in the adsorption tanks 19a and 19b by the exhaust valve 22 during the pressure equalization process, and wasteful energy consumption can be suppressed.

  According to the present embodiment, it is possible to eliminate the control that has conventionally avoided the unloading and stopping of the compressor 4 by exhausting the compressed air with the exhaust valve. Further, since the compressed air in the adsorption tanks 19a and 19b is not exhausted by the exhaust valve 22 during the pressure equalizing process, useless energy can be pushed. Moreover, since high-pressure air can be supplied, purification efficiency can be increased.

  A second embodiment of the present invention will be described. The configuration of the gas separation device is the same as that shown in FIG. The same components as those of the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  In Example 2, when the pressure range of P1 and P2 during the pressure equalization process is small, or when the use of purified gas is small, the air tank pressure is easily stored in the air tank 5 when it reaches P2. The compressor 4 can be continuously operated without exhausting by supplying compressed air.

  The separation process of the gas separation device 1 in the present embodiment is as shown in (1) to (4) of FIG. (1) to (3) are the same as in the first embodiment. In the pressure equalization process shown in FIG. 5 (3), the adsorption tank 19a after the take-out process shown in FIG. 5 (2) and the adsorption tank 19b to be the next adsorption process are in the open state of the upper pressure equalization valve 35 and the lower pressure equalization valve. To communicate nitrogen gas from 19a to 19b.

  Since the compressed air stored in the air tank 5 is used t seconds before the pressure detected by the pressure detection means 8 reaches the equalization change control pressure P2, the supply valve as shown in (4) of FIG. 18a is opened, and the lower pressure equalizing valve 26 on the air tank 5 side is closed. On the other hand, the upper pressure equalizing valve 36 on the side opposite to the air tank 5 (on the nitrogen tank 41 side) remains open. That is, the supply valve 18a on the side of the adsorption tank 19a that has been performing the extraction process in the process before the pressure equalization process is opened. Thereby, compressed air is sent to the adsorption tank 19a, and the nitrogen gas refine | purified in the adsorption tank 19a is pushed up from the bottom. Furthermore, by sending it to the adsorption tank 19b via the upper pressure equalizing valve 36, the internal state of the adsorption tank 19b, which is the next adsorption step, can be brought into favorable conditions (high pressure and high purity).

  According to the present embodiment, the increase rate of the pressure in the air tank 5 is large, and even when the pressure is likely to be P2 or more, it is possible to avoid the stop of the compressor 4 and perform gas separation without wasting compressed air. .

  t seconds may be fixed. Or you may determine by the raise state of a pressure.

  The increase in pressure is promoted when the flow rate of the purified gas used is small, so that it can be monitored by the flow rate sensor 61 or the pressure fluctuations in the nitrogen tank 41 and the adsorption tank 19.

  The embodiments described so far are merely examples of implementation in carrying out the present invention, and the technical scope of the present invention is not limitedly interpreted by these. That is, the present invention can be implemented in various forms without departing from the technical idea or the main features thereof. Further, the present invention may be implemented by combining a plurality of embodiments.

DESCRIPTION OF SYMBOLS 1 ... PSA type gas separation device 2 ... Compressor part 3 ... PSA part 4 ... Air compressor 5 ... Air tank 6 ... Air dryer 7 ... Drain filter 8 ... Pressure detecting means 18 ... supply valve 19 ... adsorption tank 22 ... exhaust valve 23 ... exhaust port 26 ... lower pressure equalizing valve 36 ... upper pressure equalizing valve 38 ... removal valve 41 ..Nitrogen tank 60 ... Control unit

Claims (6)

A compressor for compressing air;
An air tank for storing compressed air;
A plurality of adsorption tanks filled with an adsorbent and separating one gas of compressed air supplied from the air tank and separating the other gas as product gas;
A controller that controls operation and stop of the compressor main body and a gas separation step in the adsorption tank;
When the pressure of the air tank becomes equal to or higher than the control pressure, the control unit switches the compressor from a normal operation state to an unload operation state or a stop state, and the adsorption tank increases the control pressure during the pressure equalization process. The gas separation device according to claim 1.   The said control part supplies compressed air to the said adsorption tank from the said air tank, when the pressure of the said air tank reaches the said control pressure at the time of the said pressure equalization process of the said adsorption tank. The gas separation device as described.   The gas separation device according to claim 1, wherein the control unit does not exhaust the gas in the adsorption tank during the pressure equalization step.   3. The gas separation according to claim 2, wherein the control unit supplies compressed air from the air tank to the adsorption tank in which the extraction process for extracting the separated product gas is performed before the pressure equalization process. apparatus.   The gas separation device according to claim 2, wherein the control unit closes a pressure equalizing valve on the air tank side.   6. The gas separation device according to claim 5, wherein the control unit opens a pressure equalizing valve on the side opposite to the air tank.

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