JP2021142447A - Pressure booster valve unit for pressure swing adsorption apparatus, pressure swing adsorption apparatus, control method of pressure swing adsorption apparatus - Google Patents

Abstract

To contribute to the efficient operation of a PSA apparatus by preventing the transition of a compressor to an unload operation.SOLUTION: A pressure booster valve unit 3 is connected to a compressor 2 and a gas generation unit 10, and relays a gaseous starting material from the compressor 2 to the gas generation unit 10. The pressure booster valve unit 3 includes a pressure booster valve 35 and pressure detection means 36 for detecting a pressure on the delivery side of the compressor 2. The compressor 2 is configured to transition to an unload operation when the pressure on the delivery side increase to an unload start pressure. When the pressure detection means 36 detects a first pressure that is less than the unload start pressure, the pressure booster valve unit 3 introduces the gaseous starting material from the compressor 2 to the pressure booster valve 35 to operate the pressure booster valve 35, and supplies the gaseous starting material boosted by the pressure booster valve 35 to the gas generation unit 10 while reducing the pressure on the delivery side of the compressor 2. Flow rate detection means may be used instead of the pressure detection means 36.SELECTED DRAWING: Figure 1

Description

The present invention relates to a pressure boosting valve unit for a Pressure Swing Adsorption (PSA) device, a PSA device, and a method for controlling the PSA device.

The pressure swing adsorption device (hereinafter, PSA device) adsorbs a specific gas from the raw material gas to generate a target gas. The PSA device includes a device body and a compressor. The main body of the device includes a gas generation unit and a gas supply unit.

The gas generation unit includes an adsorption tank filled with an adsorbent that exhibits a high adsorption force for a specific gas. The gas generation unit introduces the raw material gas into the adsorption tank and pressurizes the inside of the adsorption tank to adsorb a specific gas in the raw material gas to the adsorbent to generate the target gas, and also to generate the target gas. The adsorbent is regenerated by reducing the pressure and releasing the gas adsorbed on the adsorbent to the outside of the adsorbent tank. The gas generating unit repeats the generation of the target gas and the regeneration of the adsorbent.

The gas generation unit of the PSA apparatus of Patent Document 1 is provided with two adsorption tanks, and while generating the target gas in one adsorption tank, the adsorbent is regenerated in the other adsorption tank, and these are alternately alternated in predetermined time units. Repeat to. As a result, the target gas can be continuously generated. The gas generation unit of the PSA apparatus of Patent Document 2 constitutes one group with a plurality of adsorption tanks, and the gas generation capacity can be adjusted by increasing or decreasing such groups.

The gas supply unit supplies the target gas generated by the gas generation unit to the outside of the PSA device. The gas supply unit includes a buffer tank for storing the target gas and the like.

The compressor compresses the raw material gas and supplies it to the gas generation unit. Various compressors can be used in the PSA apparatus. Generally, when the pressure on the discharge side of the compressor rises to a predetermined pressure (unloading start pressure), the compressor shifts to the unloading operation (for example, Patent Document 3).

When the compressor shifts to unload operation, its power consumption becomes smaller than that in load operation. However, during this time, the compressor does not produce a compressed source gas. Therefore, it can be said that the shift to unload operation is a waste of energy for the PSA device as a whole.

It is desirable to be able to supply the raw material gas to the gas generator at the highest possible pressure while preventing the compressor from shifting to unload operation. Therefore, it is desirable that the maximum pressure on the discharge side of the compressor is adjusted to be slightly lower than the unload start pressure in a series of steps of gas generation by the PSA method. However, the ability to generate compressed raw material gas varies depending on the compressor manufacturer even if the output is the same, and the above adjustment is not easy.

Japanese Unexamined Patent Publication No. 2010-75778 Japanese Unexamined Patent Publication No. 2001-327829 Japanese Unexamined Patent Publication No. 2020-15521

An object of the present invention is to provide a pressure booster valve unit capable of preventing the compressor from shifting to unload operation and contributing to efficient operation of the PSA device. Another object of the present invention is to provide a PSA device provided with a pressure boosting valve unit and a method for controlling a PSA device using the pressure boosting valve unit.

According to the present invention, there is provided a pressure boosting valve unit for relaying a raw material gas from a compressor of a pressure swing suction device to a gas generation unit of the pressure swing suction device.
The pressure booster valve unit
A first flow path including an inlet for receiving the raw material gas discharged from the compressor and an outlet for sending the raw material gas to the gas generating unit, and the like.
A second flow path that branches from the first flow path and joins the first flow path again.
The pressure booster valve provided in the second flow path and
A pressure detecting means for detecting the pressure on the discharge side of the compressor, and
An opening / closing means for opening / closing the second flow path is provided.
When the pressure detecting means detects the first pressure, the second flow path is opened by the opening / closing means so that the raw material gas can be introduced into the pressure boosting valve through the inlet and the pressure is boosted by the pressure boosting valve. The raw material gas can be released through the outlet.

When the pressure detecting means detects a second pressure that is less than the first pressure when the second flow path is open, the second flow path may be closed by the opening / closing means. The pressure detecting means may be a pressure sensor having a hysteresis characteristic of turning on at the first pressure and turning off at the second pressure. The pressure boosting valve unit may further include a backflow prevention means for preventing backflow of the first flow path between the branch point and the confluence of the second flow path.

Further, according to the present invention, a PSA device is provided.
The PSA device is
A gas generator that adsorbs a specific gas from the raw material gas by the pressure swing adsorption method to generate the target gas,
A compressor that compresses and discharges the raw material gas, and shifts to unload operation when the pressure on the discharge side rises to the unload start pressure.
A pressure boosting valve unit connected to the compressor and the gas generating unit for relaying the raw material gas from the compressor to the gas generating unit is provided.
The pressure booster valve unit
Booster valve and
A pressure detecting means for detecting the pressure on the discharge side of the compressor is provided.
When the pressure detecting means detects a first pressure that is lower than the unload start pressure, the raw material gas from the compressor is introduced into the pressure boosting valve to operate the pressure boosting valve, and the discharge side of the compressor is operated. The raw material gas boosted by the pressure boosting valve is supplied to the gas generation unit while reducing the pressure of the above.

When the pressure detecting means detects a second pressure lower than the first pressure when the pressure boosting valve is operated, the pressure booster valve unit stops the introduction of the raw material gas into the pressure booster valve and stops the operation of the pressure booster valve. Then, the raw material gas may be relayed from the compressor to the gas generation unit without being introduced into the pressure boosting valve. The gas generating unit includes a plurality of adsorption tanks filled with an adsorbent that preferentially adsorbs the specific gas over the target gas, introduces the raw material gas into a certain adsorption tank, and adds the inside of the certain adsorption tank. While pressing and adsorbing the specific gas to the adsorbent in the certain adsorption tank to generate the target gas, the pressure in another adsorption tank is reduced to regenerate the adsorbent in the other adsorption tank. The pressure / regeneration step and the pressure equalizing step of equalizing the pressure between the certain adsorption tank and the other adsorption tank after the pressurization / regeneration step may be carried out. Then, the pressure boosting valve may be operated during the pressurization / regeneration step and may be stopped during the pressure equalization step.

In addition, a control method for controlling the PSA device is provided.
The control method is
Before the pressure detecting means detects the first pressure which is lower than the unload starting pressure, the raw material gas is supplied from the compressor to the gas generating unit via the pressure boosting valve unit without introducing the raw material gas into the pressure boosting valve. death,
When the pressure detecting means detects the first pressure, the raw material gas is introduced from the compressor into the pressure boosting valve to operate the pressure boosting valve, and the pressure boosting valve is reduced while reducing the pressure on the discharge side of the compressor. The raw material gas boosted by the pressure is supplied to the gas generation unit, and the pressure is increased.
When the pressure detecting means detects a second pressure lower than the first pressure when the pressure boosting valve is operating, the introduction of the raw material gas into the pressure boosting valve is stopped, the pressure boosting valve is stopped, and the raw material is operated. The gas is supplied from the compressor to the gas generating unit via the pressure boosting valve unit without introducing the gas into the pressure boosting valve.

The control method is
While introducing the raw material gas from the compressor into an adsorption tank, pressurizing the inside of the adsorption tank, and adsorbing the specific gas to the adsorbent in the adsorption tank to generate the target gas, The first pressurization / regeneration step of depressurizing another adsorption tank to regenerate the adsorbent in the other adsorption tank, and
The raw material gas from the compressor is introduced into the other adsorption tank, the inside of the other adsorption tank is pressurized, and the specific gas is adsorbed on the adsorbent in the other adsorption tank to obtain the target gas. A second pressurizing / regenerating step of depressurizing the adsorbent tank while generating the adsorbent to regenerate the adsorbent in the adsorbent tank.
After the first and second pressurization / regeneration steps, a pressure equalizing step for equalizing the pressure between the one suction tank and the other suction tank is provided.
The control method further
The pressure boosting valve may be operated during the first and second pressurization / regeneration steps and stopped during the pressure equalization step.

The PSA apparatus may use a flow rate detecting means instead of the pressure detecting means. When the flow rate detecting means detects that the flow rate of the raw material gas has decreased to a predetermined flow rate due to an increase in the pressure of the raw material gas during the pressurization / regeneration step, the pressure boosting valve unit causes the compressor. The raw material gas from the above is introduced into the pressure boosting valve to operate the pressure boosting valve, and the raw material gas boosted by the pressure boosting valve is supplied to the gas generation unit while reducing the pressure on the discharge side of the compressor. do. Here, the predetermined flow rate is larger than the flow rate corresponding to the unload start pressure. The pressure boosting valve unit may stop the operation of the pressure boosting valve in response to the start of the pressure equalizing step.

The pressure booster valve unit according to the present invention can prevent the compressor from shifting to the unload operation and contribute to the efficient operation of the PSA device.

It is the schematic of the example PSA apparatus of this invention. It is the schematic of the pressure boosting valve unit of the PSA apparatus of FIG. The hysteresis characteristics of the pressure sensor will be described. 4A-4D show the gas production cycle and pressure changes. 5A and 5B show the relationship between air volume and pressure. It is the schematic of the PSA apparatus which concerns on a comparative example. It is another example of a gas generation part. It is the schematic of another example PSA apparatus of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows an exemplary PSA device. The PSA apparatus adsorbs a specific gas from the raw material gas by the PSA method to generate a target gas. For example, the PSA device uses air as a raw material gas. In this case, the PSA device includes an oxygen PSA device that adsorbs nitrogen to generate oxygen, a nitrogen PSA device that adsorbs oxygen to generate nitrogen, and a PSA dryer that adsorbs moisture to generate dry air.

The PSA device includes a device main body 1, a compressor 2, and a pressure booster valve unit 3. The apparatus main body 1 stores the gas generation unit 10 that adsorbs a specific gas from the raw material gas to generate the target gas by the PSA method and the target gas generated by the gas generation unit 10 as product gas and externally. It is provided with a gas providing unit 11 for providing.

The gas generation unit 10 includes a plurality of adsorption tanks T1 and T2 (two in the embodiment) that are parallel to each other. Adsorbents (not shown) are filled in the adsorption tanks T1 and T2. The adsorbent has the property of preferentially adsorbing a specific gas over the target gas (product gas). In the case of an oxygen PSA device, for example, a zeolite adsorbent that preferentially adsorbs nitrogen gas over oxygen gas is used. In the case of a nitrogen PSA apparatus, for example, a molecular sieve activated carbon adsorbent that preferentially adsorbs oxygen gas over nitrogen gas is used. In the case of PSA dryers, a desiccant is used as the adsorbent.

The gas generation unit 10 includes a first flow path group 12 connected to each primary side of the adsorption tanks T1 and T2, and a second flow path group 13 connected to each secondary side of the adsorption tanks T1 and T2. , A plurality of on-off valves SV1-SV8 provided at predetermined positions of the first and second flow path groups 12 and 13. The first flow path group 13 includes an inlet 14 for taking in the raw material gas and an outlet 15 for discharging the specific gas to the outside.

The gas supply unit 11 includes a flow path 16 extending from the second flow path group 13, a buffer tank BT provided in the flow path 16 and storing a target gas from the second flow path group 13. The flow path 16 includes a product outlet 17 for providing the target gas as a product gas to the outside. In the embodiment, the inlet 14 of the gas generating unit 10 and the product outlet 17 of the gas providing unit 11 function as the inlet and the product outlet of the apparatus main body 1.

Since the structure of the apparatus main body 1 (10, 11) has the same structure as that of Patent Document 1 and the like, the details thereof will be omitted.

A method in which the gas generating unit 10 generates a target gas from a raw material gas by the PSA method will be described with reference to FIGS. 1 and 4A. In FIG. 4A <1>, among the on-off valves SV1-SV8, those in the open state are painted white, and those in the closed state are painted black.

As shown in <1>, when the on-off valve SV1 is opened, the raw material gas is supplied from the compressor 2 described later to the gas generation unit 10 and introduced into the suction tank T1, and the pressure in the suction tank T1 gradually rises to a predetermined value. When the pressure exceeds, a specific gas in the raw material gas is adsorbed by the adsorbent, and the target gas begins to be generated. At this time, although the on-off valve SV5 is opened, it does not flow to the buffer tank BT until the pressure in the suction tank T1 exceeds the pressure in the buffer tank BT. On the other hand, when the on-off valve SV4 is opened, the pressure inside the adsorption tank T2 is reduced, and the specific gas adsorbed by the adsorbent in the adsorption tank T2 is desorbed and discharged from the adsorption tank T2 from the discharge port 15. That is, the adsorbent is being regenerated.

As shown in <2>, when the pressure in the adsorption tank T1 exceeds the pressure in the buffer tank BT, the target gas flows from the secondary side of the adsorption tank T1 to the buffer tank BT through the second flow path group 13, and then. , Is provided to the outside as a product gas through the product outlet 17. On the other hand, in the adsorption tank T2, the regeneration of the adsorbent continues. 4A <1> <2> will be hereinafter referred to as a first pressurization / regeneration step.

As described in <3>, after the first pressurization / regeneration step, the gas generation unit 10 closes the on-off valves SV1, SV4, SV5, opens the on-off valves SV7, SV8, and communicates the suction tanks T1 and T2 with each other. The pressure of both adsorption tanks T1 and T2 is equalized. FIG. 4 <3> is hereinafter referred to as a pressure equalizing step.

As described in <4> and <5>, after the pressure equalizing step, the gas generating unit 10 introduces the raw material gas from the compressor 2 into the suction tank T2 under the control of the on-off valves SV1-SV8, and then introduces the raw material gas from the compressor 2 into the suction tank T2. While the inside is pressurized to generate the target gas, the inside of the adsorption tank T1 is depressurized to regenerate the adsorbent in the adsorption tank T1. 4A <4> <5> are the second pressurization / regeneration steps.

As shown in <6>, the pressure equalization step is performed again after the second pressurization / regeneration step. Therefore, in the gas generation unit 10, FIG. 4A <1>-<3> and <4>-<6> are set as half cycles, and <1>-<6> are set as one cycle, and this is repeated and continuously. Produce the desired gas.

As shown in FIG. 1, the compressor 2 is connected to the gas generating unit 10 via a pressure boosting valve unit 3, which will be described later. The compressor 2 is configured to take in, compress, and discharge the raw material gas. Further, the compressor 2 shifts to the unload operation when the pressure on the discharge side (that is, the pressure of the compressed raw material gas to be discharged) rises to a predetermined pressure (hereinafter referred to as the unload start pressure). It is configured in.

As the compressor 2, for example, the one disclosed in Patent Document 3 may be used. The compressor 2 includes a compression unit 20 configured to compress the raw material gas (to generate a compressed raw material gas), an intake port (not shown) for taking the raw material gas into the compression unit 20, and compression. It has a discharge port 21 for discharging the produced raw material gas to the outside. The compression unit 20 includes a motor, an engine, or the like that serves as a drive source for compressing the raw material gas.

When the pressure on the discharge side of the compressor 2 rises to the unload start pressure, the compressor 2 closes the intake control valve (not shown) and closes the intake port, thereby stopping the intake air to the compression unit 20 and compressing the raw material gas (compressor 2). (Generation of compressed raw material gas) is stopped. On the other hand, the compressor 2 does not completely stop the drive source such as the motor or engine of the compression unit 20. In this way, unload operation (no-load operation / idling) is carried out.

In addition to the above, the compressor 2 may be an inverter type that can control the rotation speed of the motor according to the amount of the supplied raw material gas. As the compressor 2, various other well-known compressors may be adopted.

As shown in FIG. 1, the pressure boosting valve unit 3 is connected to the compressor 2 and the gas generation unit 10 in order to relay the raw material gas from the compressor 2 to the gas generation unit 10. The pressure boosting valve unit 3 includes a housing 30, a first flow path 31, and a second flow path 32. The first flow path 31 has an inlet 33 connected to a discharge port 21 of the compressor 2 for receiving the raw material gas from the compressor 2, and an inlet 14 of the gas generating section 10 for sending the raw material gas to the gas generating section 10. Includes an outlet 34 connected to. The second flow path 32 branches from the first flow path 31 and rejoins the first flow path 32.

As shown in FIG. 2, the pressure booster valve unit 3 further includes a pressure booster valve 35 provided in the second flow path 32. As the pressure boosting valve 35, a known one may be used. The pressure boosting valve 35 operates when the raw material gas is introduced into the primary side (inlet 33 side) thereof, and boosts the raw material gas on the secondary side (outlet 34 side) thereof. A well-known booster valve 35 can be used.

Further, the pressure boosting valve unit 3 includes a pressure detecting means for detecting the pressure on the discharge side of the compressor 2. The pressure detecting means of the embodiment is a pressure sensor 36. It is connected to the first flow path 31 upstream from the branch point 320 of the second flow path 32, and detects the pressure on the discharge side (primary side of the booster valve 35) of the compressor 2. The pressure sensor 36 is configured to be able to detect at least a first pressure P1 that is less than the unload start pressure and a second pressure P2 that is less than the first pressure P1. As the pressure sensor 36, a well-known one may be used. For example, as shown in FIG. 3, it may have a hysteresis characteristic that turns on at the first pressure P1 and turns off at the second pressure P2 after turning on.

Further, the pressure boosting valve unit 3 includes an opening / closing means for opening / closing the second flow path 32. The opening / closing means of the embodiment is an on-off valve 37, which is provided in the second flow path 32 upstream of the pressure boosting valve 35.

Further, the pressure boosting valve unit 3 includes a backflow prevention means for preventing backflow of the first flow path 31 between the branch point 320 and the confluence point 321 of the second flow path 32. The check valve 38 of the embodiment is provided in the first flow path 31 between the branch point 320 and the confluence point 321.

The booster valve unit 3 normally closes the second flow path 32 by an on-off valve 37. At this time, the raw material gas is introduced through the inlet 33, flows through the first flow path 31 without passing through the second flow path 32 (without operating the pressure boosting valve 35), and can be discharged through the outlet 34.

When the pressure sensor 36 detects the first pressure P1, the pressure boosting valve unit 3 opens the on-off valve 37, thereby opening the second flow path 32. As a result, the raw material gas can be introduced to the primary side of the pressure boosting valve 35 through the inlet 33 (the pressure boosting valve 35 can be operated by using the raw material gas as a power source), and the pressure boosting valve 35 of the pressure boosting valve 35 is boosted by the pressure boosting valve 35. The raw material gas on the secondary side can be released through the outlet 34. The check valve 38 prevents the raw material gas whose pressure has been increased on the secondary side from flowing back through the first flow path 31.

When the pressure sensor 36 detects the second pressure P2 when the second flow path 32 is in the open state (when the pressure booster valve 35 is operating), the pressure booster valve unit 3 closes the on-off valve 37 and the second flow path 32. Close. As a result, the raw material gas can flow through the first flow path 31 through the inlet 33 without passing through the pressure boosting valve 35, and can be discharged through the outlet 34 again.

A control method for the entire PSA device will be described with reference to FIGS. 4A, C, and D. FIG. 4C shows the pressure change on the discharge side of the compressor 2, and FIG. 4D shows the pressure change of the suction tank T1 or T2 to be pressurized. In FIGS. 4C and 4D, it is assumed that the unload start pressure is set to 0.8 Mpa, the first pressure P1 is set to 0.78 Mpa, which is slightly smaller than 0.8 MPa, and the second pressure is set to 0.55 Mpa. Note that these values are merely examples. The operation control of each component of the booster valve unit 3 below is performed by a control unit (for example, PLC) in the booster valve unit 3 (not shown).

The compressor 2 supplies the compressed raw material gas to the gas generation unit 10 via the pressure booster valve unit 3. The gas generation unit 10 carries out the first pressurization / regeneration step (FIGS. 4A <1> <2>) using the raw material gas from the compressor 2. The pressure begins to rise with the start of the first pressurization / regeneration step (see FIGS. 4C and 4D). At the start of the first pressurization / regeneration step, the pressure on the discharge side of the compressor 2 is smaller than the first pressure P1, the booster valve unit 3 closes the second flow path 32, and operates the booster valve 35. Only the raw material gas is relayed from the compressor 2 to the gas generation unit 10.

When the pressure on the discharge side of the compressor 2 rises to P1, this is detected by the pressure sensor 36. Then, the pressure booster valve unit 3 opens the on-off valve 37 to open the second flow path 32, introduces the raw material gas from the compressor 2 into the pressure booster valve 35, and operates the pressure booster valve 35. By introducing the raw material gas into the pressure boosting valve 35, the pressure on the discharge side is reduced (FIG. 4C). Then, the raw material gas is increased in pressure on the secondary side of the pressure increasing valve 35 by the operation of the pressure increasing valve 35, is supplied to the gas generation unit 10 through the outlet 34, and is introduced into the adsorption tank T1. That is, although the pressure on the discharge side decreases, the pressure in the suction tank T1 continues to increase although it is gentle (FIG. 4D). Therefore, it is also possible to provide the suction tank T1 with a pressure exceeding the unload start pressure.

Since a part of the raw material gas is used for operating the pressure boosting valve 35, not all the raw material gas from the compressor 2 is supplied to the gas generation unit 10, but a part of the raw material gas is supplied in a boosted state. can do. The supply ratio of the raw material gas from the compressor 2 to the gas generation unit 10 depends on the performance of the pressure booster valve 35 and the like.

After that, the gas generation unit 10 carries out a pressure equalizing step (FIG. 4A <3>). At this time, a pressure drop occurs, and the second pressure P2 (<P1) is detected by the pressure sensor 36. Then, the pressure boosting valve unit 3 closes the on-off valve 37, closes the second flow path 32, and stops the operation of the pressure boosting valve 35.

Next, the gas generation unit 10 carries out the second pressurization / depressurization step and the pressure equalization step (FIG. 4A <3>-<6>). Since the operation of the booster valve unit 3 at this time is the same as that of the previous half cycle, the description thereof will be omitted.

As described above, in the embodiment, the pressure boosting valve unit 3 is used to supply the raw material gas boosted by the pressure boosting valve 35 to the gas generation unit 10 while preventing the compressor 2 from shifting to the unload operation. do.

4B and 6 show a comparative example in which the booster valve unit 3 is not included. Since FIG. 6 is the same as the conventional configuration, the same reference numerals are given and the description thereof will be omitted. When the compressor 2 shifts to the unload operation as shown in FIG. 4B, its power consumption is lower than that in the full load operation. However, since the operation is continued without producing the compressed raw material gas, it can be said that the electric power is wasted.

For example, in a non-inverter compressor, the power consumption during unload operation is generally about 70% of that during full load operation, and about 70% of the power consumption during full load operation is wasted. There is. Further, in the inverter type compressor, the power consumption during the unload operation is generally about 30% of the power consumption during the full load operation, which is lower than that of the non-inverter type, but is about 30 during the full load operation. It is wasting% of electricity.

On the other hand, the pressure booster valve unit 3 can eliminate the state in which the compressor 2 shifts to the unload operation and does not generate the compressed raw material gas at all, so that it can contribute to the efficient implementation of the PSA apparatus.

5A and 5B show the relationship between the air volume and the pressure to the gas generating unit 10 in the comparative example (FIG. 5A) and the embodiment (FIG. 5B) of the present application, with the unloading start pressure of 0.80 MPa. In the embodiment of the present application, the difference between the air volume increase S1 and the air volume decrease S2 can be provided at a pressure larger than the unload start pressure.

The booster valve unit 3 has an advantage that it can be used by being incorporated into an existing PSA device. As shown in FIG. 7 and Patent Document 2, the pressure boosting valve unit 3 is composed of a plurality of adsorption tanks (two in the embodiment) to form one group, and the gas is increased or decreased by such increase or decrease of the groups U1-U5. It may be applied to the gas generation unit 10 of the apparatus main body 1 whose generation capacity can be adjusted. Further, the pressure boosting valve unit 3 may be provided as a separate body from the device main body 1 as shown in FIG. 1, or may be provided in the device main body 1.

As an energy-saving measure for factories, it is common to reduce the pressure of compressed air (an example of raw material gas). Even when the pressure of the compressed air in the factory is less than the design pressure required by the device body 1, this function allows the compressed air in the factory to be used as the pressure booster valve unit 3 to provide the design pressure required by the device body 1. Can be boosted and supplied. Due to the mechanism of the booster valve unit 3, extra compressed air is used to operate the booster valve, but the existing method of purchasing a compressor dedicated to the PSA device, the installation area of the compressor, maintenance costs, etc. The customer may be able to make a choice in consideration of the merit that the equipment cost of the entire factory including the above is expected to be reduced.

As is clear from the above, the first pressure P1 is set to be lower than the unload start pressure, but is preferably set to a value close to the unload start pressure. For example, the first pressure P1 is preferably set to a value of 80% or more, more preferably 90% or more of the unload start pressure. Naturally, the first pressure P1 may be set to a value less than 80% of the unload start pressure.

<Experimental example>
As one of the performances as a gas generator, the recovery rate of product gas is specified in JIS B9951 5.2.2. The recovery rate (%) of the product gas is (the volume of the target gas taken out as a product) ÷ (the volume of the target gas contained in the raw material) × 100. Simply fixing the recovery rate and increasing the (target gas volume contained in the raw material) (denominator) will increase the (target gas volume taken out as a product) (numerator). Assuming that the raw material gas is air, if the volume of the raw material air is increased, the amount of the product gas is also increased. The pressure booster valve unit eliminates the state in which the compressor does not generate compressed air (unload operation), and can increase the amount of the target gas by increasing the amount of compressed air. That is, due to the function of the pressure booster valve unit, the compressor continues to operate in full operation without shifting to the unload operation, increasing the amount of compressed air and, as a result, increasing the amount of product gas.

An experiment was conducted with the PSA device of the comparative example not including the pressure boosting valve unit and the PSA device of the embodiment of the present application including the pressure boosting valve unit. The raw material gas was air, and the target gas (product gas) was nitrogen.

Theoretical value Compressor air volume 1600 L / min (26.6 L / sec)
Nitrogen gas recovery rate approx. 20% (air ratio)
Nitrogen purity (nitrogen + argon) 99.99% condition Pressurization and depressurization are alternately repeated every 60-second cycle (half cycle in FIG. 4A).

Without booster valve unit (comparative example)
Compressor unloading operation 7 seconds / minute Compressed air generated by the compressor (60 seconds-7 seconds) x 26.6 L / sec = 1410 L / min Nitrogen gas generated 1410 x 20% = 282 L / min

With booster valve unit (embodiment of the present application)
No unload time of compressor No drive time of booster valve 7 seconds / min 7 seconds Compressed air amount by booster valve The amount of air consumed to operate the booster valve is about 50% of the supply air amount.
26.6 L / sec x 7 seconds x 50% ≈ 93 L / min increase When the air generation amount of 1410 L / min for the total operating time (53 seconds) is added to the increased amount, it becomes 1503 L / min.
Nitrogen gas generation 1503 x 20% = 300.6 L / min

Increase in nitrogen gas withdrawal 300.6 L / min-282 L / min = 18.6 L / sec The increase at a percentage is 106%.

Therefore, by using the pressure booster valve unit, the amount of nitrogen gas (target gas) taken out increased by about 6%. This is because, in the comparative example, the compressor shifts to the unload operation every half cycle and does not generate any compressed air for about 7 seconds, while in the embodiment of the present application, the compressor operates in the unload operation. This is because compressed air is constantly generated without shifting to.

Considering the power consumption, in the comparative example, the unload time (seconds) is 11.6% = (7/60) × 100 with respect to the pressure swing cycle (60 seconds) described above, and the compressor operates. During the time, about 11% of the operating time is not used for the production of nitrogen gas. During this time, the compressor is being operated wastefully. Assuming that the power consumption of the compressor is about 70% of the total power consumption due to the shift to the unload operation, about 8.46% of the total power consumption is wasted as shown in the following formula. Will be consumed by.
(7 seconds x 70%) / {(53 seconds x 100%) + (7 seconds x 70%)} x 100 = 8.46%

On the other hand, in the embodiment of the present application, about 8.46% of the electric power that was wasted in the comparative example can be effectively used for the generation of compressed air. Therefore, electric power can be consumed without waste.

FIG. 8 shows another exemplary PSA device. The pressure boosting valve unit 3 includes a flow rate sensor 39 as a flow rate detecting means for detecting the flow rate (air volume) of the raw material gas flowing from the compressor 2 to the gas generating unit 10 instead of the pressure detecting means (pressure sensor 36). .. As the flow rate sensor 39, a well-known one may be used.

When the gas generation unit 10 performs the first / second pressurization / regeneration steps (FIGS. 4A <1> <2> / <4> <5>), as shown in FIGS. 4C and 4D, the discharge side of the compressor 2 The pressure and the pressure of the suction tanks T1 / T2 increase. As the pressure rises, the flow rate of the raw material gas from the compressor 2 gradually decreases. That is, during the first and second pressurization / regeneration steps, there is an inversely proportional relationship between the pressure of the raw material gas and the flow rate, and therefore there is a flow rate corresponding to the unload start pressure (referred to as the unload start flow rate).

The flow rate of the raw material gas decreases as the pressure of the raw material gas in the discharge side and the adsorption tank T1 / T2 during the first / second pressurization / regeneration process increases. When the raw material gas drops to a predetermined flow rate larger than the unload start flow rate, this is detected by the flow rate sensor 39.

In response to this detection, the pressure booster valve unit 3 opens the on-off valve 37 to open the second flow path 32, and introduces the raw material gas from the compressor 2 into the pressure booster valve 35 to increase the pressure, as in the previous embodiment. The pressure valve 35 is operated, whereby the raw material gas boosted by the pressure boosting valve 35 is supplied to the gas generation unit 10 while reducing the pressure on the discharge side of the compressor 2.

After that, the gas generation unit 10 carries out a pressure equalizing step (FIG. 4A <3> / <6>). In response to the gas generation unit 10 starting the pressure equalizing step, the pressure boosting valve unit 3 closes the on-off valve 37, closes the second flow path 32, and stops the operation of the pressure boosting valve 35. The pressure equalizing step is started by opening the on-off valves SV7 and SV8 (also referred to as pressure equalizing valves). Therefore, for example, the pressure boosting valve unit 3 may stop the operation of the pressure boosting valve 35 in response to the switching from closing to opening of the on-off valve SV7 / SV8.

Also in this embodiment, as in the previous embodiment, it is possible to prevent the compressor 2 from shifting to the unload operation, and it is possible to enable efficient operation of the PSA device. The configuration in which the pressure boosting valve 35 is stopped in response to the start of the pressure equalizing step (opening of the pressure equalizing valve) may be adopted in the previous embodiment using the pressure sensor 36. The predetermined flow rate is preferably set in a flow rate range corresponding to the range of the first pressure P1 described in the above paragraph 0057 column, but is not limited thereto.

1 Equipment body 10 Gas generator T1, T2 Suction tank 2 Compressor 3 Pressure booster valve unit 31 First flow path 32 Second flow path 320 Branch point 321 Confluence point 33 Inlet 34 Outlet 35 Pressure booster valve 36 Pressure sensor as pressure detection means 37 On-off valve as opening / closing means 38 Check valve as backflow prevention means 39 Flow sensor P1 first pressure P2 second pressure as flow detection means

Claims (11)

A pressure boosting valve unit for relaying the raw material gas from the compressor of the pressure swing adsorption device to the gas generation unit of the pressure swing adsorption device.
A first flow path including an inlet for receiving the raw material gas discharged from the compressor and an outlet for sending the raw material gas to the gas generating unit, and the like.
A second flow path that branches from the first flow path and joins the first flow path again.
The pressure booster valve provided in the second flow path and
A pressure detecting means for detecting the pressure on the discharge side of the compressor, and
An opening / closing means for opening / closing the second flow path is provided.
When the pressure detecting means detects the first pressure, the second flow path is opened by the opening / closing means so that the raw material gas can be introduced into the pressure boosting valve through the inlet and the pressure is boosted by the pressure boosting valve. The raw material gas can be released through the outlet,
A pressure booster valve unit characterized by this. When the pressure detecting means detects a second pressure that is less than the first pressure when the second flow path is open, the second flow path is closed by the opening / closing means.
The pressure booster valve unit according to claim 1. The pressure detecting means is a pressure sensor having a hysteresis characteristic of turning on at the first pressure and turning off at the second pressure.
The pressure booster valve unit according to claim 2. Further provided is a backflow prevention means for preventing backflow of the first flow path between the branch point and the confluence of the second flow path.
The pressure booster valve unit according to any one of claims 1 to 3. A gas generator that adsorbs a specific gas from the raw material gas by the pressure swing adsorption method to generate the target gas,
A compressor that compresses and discharges the raw material gas, and shifts to unload operation when the pressure on the discharge side rises to the unload start pressure.
A pressure boosting valve unit connected to the compressor and the gas generating unit for relaying the raw material gas from the compressor to the gas generating unit is provided.
The pressure booster valve unit
Booster valve and
A pressure detecting means for detecting the pressure on the discharge side of the compressor is provided.
When the pressure detecting means detects a first pressure that is lower than the unload start pressure, the raw material gas from the compressor is introduced into the pressure boosting valve to operate the pressure boosting valve, and the discharge side of the compressor is operated. The raw material gas boosted by the pressure boosting valve is supplied to the gas generation unit while reducing the pressure.
A pressure swing suction device characterized by this. When the pressure detecting means detects a second pressure lower than the first pressure when the pressure boosting valve is operated, the pressure booster valve unit stops the introduction of the raw material gas into the pressure booster valve and stops the operation of the pressure booster valve. Then, the raw material gas is relayed from the compressor to the gas generation unit without being introduced into the pressure boosting valve.
The pressure swing suction device according to claim 5. The gas generator
A plurality of adsorption tanks filled with an adsorbent that preferentially adsorbs the specific gas over the target gas are provided.
While introducing the raw material gas into a certain adsorption tank, pressurizing the inside of the certain adsorption tank, and adsorbing the specific gas to the adsorbent in the certain adsorption tank to generate the target gas, another adsorption tank is formed. A pressurization / regeneration step of reducing the pressure to regenerate the adsorbent in the other adsorption tank, and
After the pressurization / regeneration step, a pressure equalizing step of equalizing the pressure between the one suction tank and the other suction tank is carried out.
The pressure boosting valve is operated during the pressurization / regeneration step and is stopped during the pressure equalization step.
The pressure swing suction device according to claim 6. It is a control method that controls the pressure swing suction device.
The pressure swing suction device is
A gas generator that adsorbs a specific gas from the raw material gas by the pressure swing adsorption method to generate the target gas,
A compressor that compresses and discharges the raw material gas, and shifts to unload operation when the pressure on the discharge side rises to the unload start pressure.
A pressure boosting valve unit connected to the compressor and the gas generating unit for relaying the raw material gas from the compressor to the gas generating unit is provided.
The pressure booster valve unit
Booster valve and
A pressure detecting means for detecting the pressure on the discharge side of the compressor is provided.
The control method is
Before the pressure detecting means detects the first pressure which is lower than the unload starting pressure, the raw material gas is supplied from the compressor to the gas generating unit via the pressure boosting valve unit without introducing the raw material gas into the pressure boosting valve. death,
When the pressure detecting means detects the first pressure, the raw material gas is introduced from the compressor into the pressure boosting valve to operate the pressure boosting valve, and the pressure boosting valve is reduced while reducing the pressure on the discharge side of the compressor. The raw material gas boosted by the pressure is supplied to the gas generation unit, and the pressure is increased.
When the pressure detecting means detects a second pressure lower than the first pressure when the pressure boosting valve operates, the introduction of the raw material gas into the pressure boosting valve is stopped, the pressure boosting valve is stopped, and the raw material gas is released. It is supplied from the compressor to the gas generating unit via the pressure boosting valve unit without being introduced into the pressure boosting valve.
A control method characterized by that. The gas generator
A plurality of adsorption tanks filled with an adsorbent that preferentially adsorbs the specific gas over the target gas are provided.
The control method is
While introducing the raw material gas from the compressor into an adsorption tank, pressurizing the inside of the adsorption tank, and adsorbing the specific gas to the adsorbent in the adsorption tank to generate the target gas, The first pressurization / regeneration step of depressurizing another adsorption tank to regenerate the adsorbent in the other adsorption tank, and
The raw material gas from the compressor is introduced into the other adsorption tank, the inside of the other adsorption tank is pressurized, and the specific gas is adsorbed on the adsorbent in the other adsorption tank to obtain the target gas. A second pressurizing / regenerating step of depressurizing the adsorbent tank while generating the adsorbent to regenerate the adsorbent in the adsorbent tank.
After the first and second pressurization / regeneration steps, a pressure equalizing step for equalizing the pressure between the one suction tank and the other suction tank is provided.
The control method further
The pressure boosting valve is operated during the first and second pressurization / regeneration steps and stopped during the pressure equalization step.
The control method according to claim 8. A gas generator that adsorbs a specific gas from the raw material gas by the pressure swing adsorption method to generate the target gas,
A compressor that compresses and discharges the raw material gas, and shifts to unload operation when the pressure on the discharge side rises to the unload start pressure.
A pressure boosting valve unit connected to the compressor and the gas generating unit for relaying the raw material gas from the compressor to the gas generating unit is provided.
The gas generator
A plurality of adsorption tanks filled with an adsorbent that preferentially adsorbs the specific gas over the target gas are provided.
While introducing the raw material gas into a certain adsorption tank, pressurizing the inside of the certain adsorption tank, and adsorbing the specific gas to the adsorbent in the certain adsorption tank to generate the target gas, another adsorption tank is formed. A pressurization / regeneration step of reducing the pressure to regenerate the adsorbent in the other adsorption tank, and
After the pressurization / regeneration step, a pressure equalizing step of equalizing the pressure between the one suction tank and the other suction tank is carried out.
The pressure booster valve unit
With the pressure booster
A flow rate detecting means for detecting the flow rate of the raw material gas flowing from the compressor to the gas generating unit is provided.
When the flow rate detecting means detects that the flow rate of the raw material gas has decreased to a predetermined flow rate as the pressure of the raw material gas increases during the pressurization / regeneration step, the raw material gas from the compressor is released. It is introduced into the pressure boosting valve and the pressure booster valve is operated to supply the raw material gas boosted by the pressure booster valve to the gas generation unit while reducing the pressure on the discharge side of the compressor.
The predetermined flow rate is larger than the flow rate corresponding to the unload start pressure.
A pressure swing suction device characterized by this. The pressure boosting valve unit operates and stops the pressure boosting valve in response to the start of the pressure equalizing step.
The pressure swing suction device according to claim 10.

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