JP6239435B2 - Gas separation device - Google Patents

Description

  The present invention relates to a gas separation device.

  A PSA (Pressure Swing Adsorption) type is known as a gas separation device. According to the PSA formula, for example, by using air as a raw material and adsorbing oxygen in the air with an adsorbent, nitrogen can be separated and nitrogen gas can be obtained as a product gas. In the PSA treatment step, the adsorbent that has adsorbed oxygen at high pressure is desorbed at low pressure, and continuous operation is performed while recovering the adsorption capacity of the adsorbent by repeated adsorption and desorption.

  As background art of this technical field, there is JP-A-61-1120 (Patent Document 1). Patent Document 1 describes that when operating with the product gas removal flow reduced, the pressure is reduced to a level substantially lower than the maximum adsorption pressure, and the adsorption time is further extended to operate the apparatus. Has been.

JP 61-11120 A

  In Patent Document 1, when the product gas extraction flow rate is reduced, the compressor is decelerated to reduce the maximum pressure of the raw material gas mixture passing through the adsorption tower, and further, the adsorption time of the pressure fluctuation type adsorption separation operation is extended to save energy. I am trying. However, if the compressor decelerates more than a certain level, the compression efficiency becomes extremely bad, so there is a limit to decelerate. Therefore, when the product take-off flow rate is extremely small, etc., even if the compressor is decelerated, the pressure in the air tank and the adsorption tower may rise above the maximum pressure, which consumes wasted power. .

  The objective of this invention is providing the gas separation apparatus which can acquire an energy-saving effect by suppressing the useless operation of a compressor.

  In order to solve the above problems, for example, the configuration described in the claims is adopted. The present invention includes a plurality of means for solving the above-described problems. For example, a gas separation device includes a compressor that compresses air and air that stores compressed air compressed by the compressor. The operation of the tank, the adsorption tank that adsorbs part of the compressed air stored in the air tank, the product gas storage tank that stores the product gas that has not been adsorbed in the adsorption tank, and the operation of the compressor and the adsorption tank A control unit that controls, when the use amount of the product gas decreases, the use amount decreases the pressure of the air tank at which the compressor starts the deceleration operation and the pressure of the air tank at which the compressor stops. It is configured to be lower than before.

  ADVANTAGE OF THE INVENTION According to this invention, the gas separation apparatus which can acquire an energy saving effect can be provided.

It is a whole block diagram of the gas separation apparatus in Example 1 of this invention. It is a control flowchart of the gas separation apparatus in Example 1 of this invention. It is a figure which shows the control pressure of the air tank in Example 1 of this invention. It is a control flow figure of the gas separation apparatus in Example 2 of the present invention. It is a control flow figure of the gas separation apparatus in Example 3 of the present invention. It is a whole block diagram of the gas separation apparatus in Example 4 of this invention.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows the overall configuration of a PSA type gas separation apparatus in the present embodiment. In FIG. 1, a 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 described as being stored separately in separate housings, but the above two units may be stored in the same housing.

  The air supply unit 2 includes a compressor 4 that compresses air, an electric motor 9 that drives the compressor 4, an inverter circuit 10 that performs capacity control, an air tank 5 that stores compressed air, and compressed air. An air dryer 6 that dehumidifies the water and a drain filter 7 that removes impurities while collecting the drain water deposited. 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 </ b> A and 19 </ b> 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 </ b> A and 19 </ b> B described later, and a predetermined gas is separated from the compressed air stored in the air tank 5. In the present embodiment, the 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, and other air may be separated from compressed air other than the atmosphere. The gas may be separated.

  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 </ b> A and 17 </ b> 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, 22B are provided with an exhaust silencer 23 with a filter for silencing at the terminal. This exhaust silencer may be provided for each adsorption tank 19A, 19B. Further, 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. The pipes 25A and 25B are opened and closed. 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 merge with 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. Pipes 35A and 35B are connected to the pipes 31A and 31B so as to connect the opposite sides of the adsorption tanks 19A and 19B to the pipes 32A and 32B. Upper pressure equalizing valves 36A and 36B that open and close are provided. The pipes 31A and 31B are provided with take-out 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 a 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. 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 the control unit. 60 is communicably connected, and operates in response to a command from the control unit 60.

  The configuration of the gas separation device 1 has been described above. Hereinafter, 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.
(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 take-off 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 process: The pressure equalization of the pair of adsorption tanks 19 after completion of the take-out process is achieved by opening and closing the upper pressure equalization valve 36 and the lower pressure equalization valve 26, and the adsorption efficiency of the next adsorption process is increased to achieve higher purity. For generating 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 process, 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.

  While the adsorption process / removal process (process (a) (b)) is performed in the adsorption tank 19A, the regeneration process (process (d)) is performed in the adsorption tank 19B. Thereafter, the (c) pressure equalization step is performed simultaneously, and the adsorption tanks 19A and 19B are exchanged to perform the adsorption step / removal step (steps (a) and (b)) and the regeneration step (step (d)). The time of the above-described adsorption step (a), take-out step (b), and pressure equalization step (c) is taken as the cycle time.

  A control flow in the present embodiment will be described with reference to FIG. In FIG. 2, when the operation of the gas separation device 1 is started, the operation is started at the standard cycle time T0 (S1). At this time, the pressure in the air tank 5 is sensed and a signal is sent to the control unit 60. By sending a command from the control unit 60 to the inverter circuit 10, the rotational speed of the electric motor 9 is controlled and the compressor 4 is operated. At this time, when the pressure in the air tank 5 reaches a specified pressure P0, the deceleration operation is started. When the pressure in the air tank 5 reaches the maximum pressure Pmax0, the compressor 4 is stopped, and when the pressure in the air tank 5 drops to the return pressure Pmin0, the operation of the compressor is resumed (S2).

  At this time, the product gas use amount Q is sensed by the flow rate detection means 61 provided at the gas separation device discharge port, and the product gas use amount Q is smaller than the threshold value Q1 set in the control unit 60 in advance. Whether or not (S3). If it is less, a signal is sent from the control unit 60 to change the cycle time from the standard cycle time T0 to the energy saving cycle time T1 (S4). At this time, the relationship between T0 and T1 is T0 <T1. Simultaneously with this cycle time change signal, the pressure at which the compressor starts decelerating operation is changed from P0 to P1, the maximum pressure Pmax0 that stops the compressor 4 is changed to Pmax1, and the return pressure Pmin0 that restarts the compressor operation is Pmin1. A signal is sent from the control unit 60 to change to (S5). At this time, the relationship between the pressures is P0> P1, Pmax0> Pmax1, and Pmin0> Pmin1. If the product gas usage Q is Q1 or more during the standard cycle time T0 operation, the standard cycle time T0 operation is continued as it is. The control pressure is also operated at P0, Pmax0, and Pmin0.

  It is determined whether or not the product gas usage amount Q is less than a threshold value Q2 that is preset in the control unit 60 during the energy saving cycle time T1 operation and is smaller than the threshold value Q1 (S6). When the cycle time is small, a signal is sent from the control unit 60 to change the cycle time from the energy saving cycle time T1 to the energy saving cycle time T2 (S7). At this time, the relationship between T1 and T2 is T1 <T2. Simultaneously with this cycle time change signal, the pressure at which the compressor 4 starts decelerating operation is changed from P1 to P2, the maximum pressure Pmax1 that stops the compressor 4 is changed to Pmax2, and the return pressure Pmin1 that restarts the compressor operation is set. A signal is sent from the control unit 60 to change to Pmin2 (S8). At this time, the relationship between the pressures is P1> P2, Pmax1> Pmax2, and Pmin1> Pmin2.

  If the product gas consumption Q is Q2 or more and less than Q1 during the energy-saving cycle time T1 operation (Q1> Q ≧ Q2), did the energy-saving cycle time T1 operation continue and the product gas consumption Q became Q1 or more? In this case, a signal is sent from the control unit 60 to operate at the standard cycle time T0, control pressures P0, Pmax0, and Pmin0.

  If the product gas usage Q is less than Q2 during the energy-saving cycle time T2, the energy-saving cycle time T2 operation is continued as it is (S10), and if the product gas usage Q is Q2 or more, the standard cycle time T0, A signal is sent from the control unit 60 to operate at the control pressures P0, Pmax0, and Pmin0. When the product gas consumption Q is Q2 or more, it is judged whether or not Q is Q1 or more. If Q is Q1 or more, operation is performed at the standard cycle time T0, control pressure P0, Pmax0, Pmin0. You may do it. In that case, although it differs from the control flow of FIG. 2, you may transfer to the step of S10 to S9.

  In the present embodiment, the cycle time to be changed and the control pressure are divided into three stages, but further stages may be provided. Further, although the threshold value for changing the cycle time is defined by the product gas generation amount Q, it may be defined by the product gas concentration, or may be defined by both the product gas generation amount Q and the product gas concentration.

  FIG. 3 is a diagram showing the relationship between each cycle time and the control pressure of the air tank in the present embodiment. In FIG. 3, the upper diagram shows the change in the control pressure of the air tank at the normal cycle time T0. At the beginning of the normal cycle time T0 in FIG. 3, the pressure equalizing process is started. When the compressor is stopped and the pressure of the air tank is reduced to the return pressure Pmin0, the operation of the compressor is resumed and the process proceeds to the adsorption process. The operation of the compressor controls the rotation speed of the electric motor at the maximum speed, and starts the deceleration operation when the pressure in the air tank reaches the deceleration operation start pressure P0. When the pressure in the air tank reaches the maximum pressure Pmax0 or reaches the cycle time T0, the compressor is stopped and one cycle is completed.

  The middle diagram of FIG. 3 shows the change in the control pressure of the air tank at the energy saving cycle time T1. In the first pressure equalization process at the energy saving cycle time T1, when the compressor is stopped and the pressure in the air tank is reduced to the return pressure Pmin1, the operation of the compressor is resumed and the process proceeds to the adsorption process. The operation of the compressor controls the rotation speed of the electric motor at the maximum speed, and starts the deceleration operation when the pressure in the air tank reaches the deceleration operation start pressure P1. When the pressure in the air tank reaches the maximum pressure Pmax1, the compressor is stopped and one cycle is completed at the cycle time T1.

  Further, the lower diagram of FIG. 3 shows a change in the control pressure of the air tank at the energy saving cycle time T2. In the first pressure equalization process at the energy saving cycle time T2, when the compressor is stopped and the pressure in the air tank is reduced to the return pressure Pmin2, the operation of the compressor is resumed and the process proceeds to the adsorption process. The operation of the compressor controls the rotation speed of the electric motor at the highest speed, and starts the deceleration operation when the pressure in the air tank reaches the deceleration operation start pressure P2. When the pressure in the air tank reaches the maximum pressure Pmax2, the compressor is stopped and one cycle is completed at the cycle time T2.

  As described above, in this embodiment, as a gas separation device, a compressor that compresses air, an air tank that stores compressed air compressed by the compressor, and a part of compressed air stored in the air tank An adsorbing tank for adsorbing the gas, a product gas storage tank for storing the product gas not adsorbed in the adsorbing tank, and a control unit for controlling the operation of the compressor and the adsorbing tank. When the usage amount decreases, the pressure of the air tank at which the compressor starts decelerating operation and the pressure of the air tank at which the compressor stops are made lower than before the usage amount decreases.

  The control unit is configured to start the operation of the compressor when the compressor stops and the pressure of the air tank drops below a predetermined pressure. The pressure of the air tank which starts operation is configured to be lower than before the amount of use decreases.

  Moreover, when the usage-amount of product gas reduces, it is comprised so that the cycle time which is the time of 1 cycle of adsorption / desorption may be made longer than before the usage-amount decreases.

  As a result, useless operation of the compressor can be suppressed, an energy saving effect can be obtained, and the load on the compressor can be reduced by lowering the control pressure, thereby extending the life of the compressor. it can.

  This embodiment will be described with reference to the control flow diagram of FIG. Since the basic configuration and operation of the apparatus are the same as those of the gas separation apparatus 1 described in the first embodiment, a description thereof will be omitted.

  In this embodiment, the product gas concentration N during the energy saving cycle time operation is sensed by the oxygen sensor 56, and the control pressure is determined by the relationship between the product gas concentration N and the product gas concentration threshold value N1 set in the control unit 60 in advance. Control to change. That is, since the product gas concentration increases as the control pressure increases, a further energy saving effect can be obtained by controlling the control pressure based on the product gas concentration.

  In FIG. 4, S1 to S4 are the same as those in the first embodiment, and the description thereof is omitted. When shifting to the energy saving cycle time T1 operation, it is determined in S11 whether the product gas concentration N is higher than N1. When the product gas concentration N is higher than N1, the pressure at which the compressor starts the deceleration operation is Pa, the maximum pressure at which the compressor 4 is stopped is Pmaxa, and the return pressure at which the compressor is restarted is Pmina ( S12). When the product gas concentration N is lower than N1, the pressure at which the compressor starts the deceleration operation is Pb, the maximum pressure at which the compressor 4 is stopped is Pmaxb, and the return pressure at which the compressor is restarted is Pminb (S13). ). At this time, the relationship between the pressures is P0> Pb> Pa, Pmax0> Pmaxb> Pmaxa, and Pmin0> Pminb> Pmina. And the process of S6 and S7 until energy saving cycle time T2 driving | operation transfer is performed similarly to Example 1. FIG.

  Then, when shifting to the energy saving cycle time T2 operation, it is determined whether or not the product gas concentration N is higher than N2 (S14). When the product gas concentration N is higher than N2, the pressure at which the compressor starts the deceleration operation is Pc, the maximum pressure at which the compressor 4 is stopped is Pmaxc, and the return pressure at which the compressor is restarted is Pminc ( S15). When the product gas concentration N is lower than N2, the pressure at which the compressor starts the deceleration operation is Pd, the maximum pressure at which the compressor 4 is stopped is Pmaxd, and the return pressure at which the compressor is restarted is Pmind (S16). ). At this time, the relationship between the pressures is P0> Pb> Pa> Pd> Pc, Pmax0> Pmaxb> Pmaxa> Pmaxd> Pmaxc, and Pmin0> Pminb> Pmina> Pmind> Pminc.

  Thereafter, whether or not the product gas usage Q during the energy saving cycle time T2 operation is less than Q2 (S10) and the subsequent processing are performed in the same manner as in the first embodiment. As in Example 1, when the product gas consumption Q is Q2 or more, it is further determined whether Q is Q1 or more. If Q is Q1 or more, the standard cycle time T0, the control pressure P0, You may make it drive | operate by Pmax0 and Pmin0. In that case, although it differs from the control flow of FIG. 4, you may transfer to the step of S10 to S9.

  As described above, in this embodiment, as a gas separation device, a compressor that compresses air, an air tank that stores compressed air compressed by the compressor, and a part of compressed air stored in the air tank An adsorbing tank for adsorbing the gas, a product gas storing tank for storing the product gas not adsorbed in the adsorbing tank, a gas sensor for measuring the concentration of the product gas, and a controller for controlling the operation of the compressor and the adsorbing tank, When the amount of product gas used decreases, the control unit sets the pressure of the air tank at which the compressor starts decelerating operation to a lower value than before the amount of use decreases, and the lower value When the concentration of the product gas detected by the above is larger than a predetermined value, it is configured to be set lower than when it is small.

  In addition, the control unit starts the operation of the compressor when the compressor stops and the pressure of the air tank drops below a predetermined pressure, and when the amount of product gas used decreases, the air tank further stops the compressor. The pressure of the air tank and the pressure of the air tank for starting the operation of the compressor are set to lower values than before the amount of use decreases, and the lower value is when the concentration of the product gas detected by the gas sensor is larger than a predetermined value. It is configured so as to be set lower than when it is small.

  Moreover, when the usage-amount of product gas reduces, it is comprised so that the cycle time which is the time of 1 cycle of adsorption / desorption may be made longer than before the usage-amount decreases.

  As a result, when the product gas concentration is sufficiently higher than the specification value of the product and has sufficient tolerance, the control pressure can be further reduced, and the load on the compressor can be further reduced and further energy saving effect Can be obtained.

  This embodiment will be described with reference to the control flow diagram of FIG. Since the configuration and operation of the apparatus are the same as those of the gas separation apparatus 1 described in the first embodiment, the description thereof is omitted.

  The product gas concentration to be purified by the gas separation device is easily affected by the ambient temperature, and the product gas concentration deteriorates when the ambient temperature is high. In addition, the purification efficiency of the product gas is improved as the adsorbent filled in the adsorption tanks 19A and 19B is adsorbed at a higher pressure. Therefore, if the ambient temperature increases while the constant control pressure P is low, the product gas concentration may fall below the specification value.

  Therefore, in the present embodiment, the controller 60 receives the ambient temperature D of the adsorption tank from the temperature sensor 62 disposed in the gas separation device, and the ambient temperature D during the operation of the energy saving cycle time T1 or the energy saving cycle time T2 by the device. When the threshold value D1 preset in the control unit 60 is exceeded, a signal is sent from the control unit 60 to change the cycle time to the normal cycle time T0, and the pressure at which the compressor starts the deceleration operation is set to P0. A signal is sent from the control unit 60 to change the maximum pressure to stop 4 to Pmax0 and the return pressure to restart the compressor operation to Pmin0.

  In FIG. 5, S1 to S3 are the same as those in the first embodiment, and the description thereof is omitted. In S3, when the usage amount Q of the product gas is smaller than the threshold value Q1, it is determined whether the ambient temperature D is lower than the threshold value D1 set in the control unit 60 in advance (S17). When D1 is exceeded, the temperature is high, and the cycle time is returned to the standard cycle time T0. If the ambient temperature D is equal to or lower than D1, the energy saving cycle time T1 is changed as in the first embodiment. In S6, when the usage amount Q of the product gas is smaller than the threshold value Q2, it is determined whether the ambient temperature D is lower than the threshold value D1 set in the control unit 60 in advance (S18). When D1 is exceeded, the temperature is high, and the cycle time is returned to the standard cycle time T0. If the ambient temperature D is equal to or lower than D1, the energy saving cycle time T2 is changed as in the first embodiment. Thereafter, the same processing as in the embodiment is performed.

  As described above, in this embodiment, as a gas separation device, a compressor that compresses air, an air tank that stores compressed air compressed by the compressor, and a part of compressed air stored in the air tank An adsorption tank for adsorbing gas, a product gas storage tank for storing product gas not adsorbed in the adsorption tank, a temperature sensor for measuring the ambient temperature of the adsorption tank, and a control for controlling the operation of the compressor and the adsorption tank The control unit reduces the air tank pressure at which the compressor starts decelerating operation when the amount of product gas used decreases, and decreases when the ambient temperature by the temperature sensor is lower than the predetermined value. It is set to be lower than before, and when it is higher, it is configured to return to the value before the usage amount decreased.

  In addition, the control unit starts the operation of the compressor when the compressor stops and the pressure of the air tank drops below a predetermined pressure, and when the amount of product gas used decreases, the air tank further stops the compressor. When the ambient temperature is lower than the specified value, the pressure of the air tank and the pressure of the air tank at which the compressor is started are lower than before the amount of use is reduced. Configure as follows.

  Moreover, when the usage-amount of product gas reduces, it is comprised so that the cycle time which is the time of 1 cycle of adsorption / desorption may be made longer than before the usage-amount decreases.

  Thereby, according to the present Example, the effect of ambient temperature can be reduced and the reliability of product gas can be improved, aiming at the energy-saving effect and the lifetime improvement of a compressor.

A present Example is described using the whole block diagram of the gas separation apparatus of FIG.
As shown in FIG. 6, in this embodiment, a plurality of compressors 4 and electric motors 9 are mounted on the air supply unit 2. Thus, the same control as in the first to third embodiments is realized by controlling the number of the plurality of compressors 4 instead of the inverter circuit 10. In addition, about another structure, since it is the same as that of the gas separation apparatus 1 demonstrated in Example 1, description is abbreviate | omitted.

  According to the present embodiment, the load on the compressor can be reduced, and an energy saving effect and a longer life of the compressor can be realized.

  Although the embodiments have been described above, the present invention is not limited to the above-described embodiments, and includes various modifications. Moreover, it is not necessarily limited to what has all the structures demonstrated. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Moreover, it is also possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

DESCRIPTION OF SYMBOLS 1 ... PSA type gas separation apparatus 2 ... Air supply unit 3 ... PSA unit 4 ... Compressor 5 ... Air tank 6 ... Air dryer 7 ... Drain filter 9 ... Electric motor 10 ... inverter circuit 19 ... adsorption tank 41 ... nitrogen tank (product gas storage tank)
44 ... Filter regulator 52 ... Silencer 56 ... Oxygen sensor 60 ... Control unit 61 ... Flow rate detection means 62 ... Temperature sensor

Claims (8)

A compressor for compressing air;
An air tank for storing compressed air compressed by the compressor;
An adsorption tank that adsorbs some of the compressed air stored in the air tank;
A product gas storage tank for storing the product gas not adsorbed in the adsorption tank;
A controller that controls the operation of the compressor and the adsorption tank;
When the usage amount of the product gas decreases, the control unit reduces the pressure of the air tank at which the compressor starts decelerating operation and the pressure of the air tank at which the compressor stops before the usage amount decreases. A gas separation device characterized by being made lower. The gas separation device according to claim 1,
The control unit starts the operation of the compressor when the compressor stops and the pressure of the air tank drops below a predetermined pressure. The gas separation device according to claim 2,
When the usage amount of the product gas is reduced, the control unit further lowers the pressure of the air tank for starting the operation of the compressor than before the usage amount is reduced. A compressor for compressing air;
An air tank for storing compressed air compressed by the compressor;
An adsorption tank that adsorbs some of the compressed air stored in the air tank;
A product gas storage tank for storing the product gas not adsorbed in the adsorption tank;
A gas sensor for measuring the concentration of the product gas;
A controller that controls the operation of the compressor and the adsorption tank;
When the usage amount of the product gas decreases, the control unit sets the pressure of the air tank at which the compressor starts a deceleration operation to a lower value than before the usage amount decreases, and the low value is The gas separation device is characterized in that when the concentration of the product gas detected by the gas sensor is larger than a predetermined value, the gas separation device is set lower than when it is small. The gas separation device according to claim 4,
The control unit starts operation of the compressor when the compressor stops and the pressure of the air tank drops below a predetermined pressure,
When the usage amount of the product gas decreases, the pressure of the air tank at which the compressor stops and the pressure of the air tank at which the compressor starts operating are set to lower values than before the usage amount decreases. The low value is set lower when the concentration of the product gas detected by the gas sensor is larger than a predetermined value as compared with a small value. A compressor for compressing air;
An air tank for storing compressed air compressed by the compressor;
An adsorption tank that adsorbs some of the compressed air stored in the air tank;
A product gas storage tank for storing the product gas not adsorbed in the adsorption tank;
A temperature sensor for measuring the ambient temperature of the adsorption tank;
A controller that controls the operation of the compressor and the adsorption tank;
The controller controls the pressure of the air tank at which the compressor starts decelerating operation when the usage amount of the product gas decreases, and the usage amount when the ambient temperature by the temperature sensor is lower than a predetermined value. The gas separation device is characterized in that it is lower than before the decrease, and when it is higher, the use amount is returned to the value before the decrease. The gas separation device according to claim 6,
The control unit starts operation of the compressor when the compressor stops and the pressure of the air tank drops below a predetermined pressure,
When the usage amount of the product gas is reduced, the pressure of the air tank at which the compressor stops and the pressure of the air tank at which the compressor starts to be operated are set when the ambient temperature is lower than a predetermined value. A gas separation device characterized by lowering the amount of use than before the amount of use and returning to a value before the amount of use is reduced when the amount of use is high. The gas separation device according to any one of claims 1 to 7,
When the amount of product gas used decreases, the control unit further increases the cycle time, which is the time of one cycle of adsorption / desorption, than before the amount of use decreases .

Images