TWI401113B - Pressure swing adsorption gas generating device - Google Patents

Description

Pressure swing adsorption gas generating device

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a pressure swing adsorption gas generating apparatus for generating nitrogen gas by a pressure swing adsorption method, and more particularly to an improvement in energy saving effect for reducing consumption of raw material air.

As one of the non-cryogenic techniques for producing nitrogen or oxygen, a PSA (pressure swing adsorption) method is known. According to the PSA method, for example, air is used as a raw material, and oxygen in the raw material air is adsorbed by an adsorbent, whereby nitrogen can be separated to obtain high-purity nitrogen as a product gas.

In the PSA process, the principle that the adsorption amount of high pressure is greater than the adsorption amount of low pressure is utilized. That is, continuous operation is performed while recovering the adsorption capacity of the adsorbent by repeating adsorption desorption, which means that the adsorbent adsorbing oxygen under high pressure desorbs oxygen at a low pressure. Therefore, in the step of PSA, two adsorption tanks filled with an adsorbent are used, and in one of the adsorption tanks, an adsorption step is performed under high pressure, during which desorption is performed at a low pressure in the other adsorption tank. step.

In this manner, in order to alternately perform the adsorption and desorption step using the two adsorption tanks, the flow path of the gas that has made the raw material air from the introduction port to the product tank through the adsorption tank is switched according to the step to be performed. That is, a plurality of valves are switched in a timely manner so that, for example, the raw material air is introduced into the adsorption tank for performing the adsorption step, and the nitrogen gas is led out from the adsorption tank, or the adsorption tank is exhausted from the desorption step. Running.

However, in practice, for example, in a place where a nitrogen generating device is used, the amount of nitrogen used is not necessarily fixed, and in many cases, nitrogen is intermittently used, and even if nitrogen is not used intermittently, the amount of nitrogen used varies with time. Further, in many cases, a plurality of nitrogen gas consumption units are used in combination with one nitrogen gas generator, and the amount of use usually varies.

On the other hand, the rated production amount of the nitrogen generating device ensures the purity of the nitrogen gas at the maximum amount of production, and the amount of the raw material air at this time is set as the rated production amount. The smaller the amount of nitrogen used than the maximum amount produced, the higher the purity of nitrogen, but the amount of raw air used is only slightly reduced.

The reason is that in order to operate at an adsorption desorption cycle having a high recovery efficiency in accordance with the maximum amount of production, the operation is performed with a smaller amount of production, and the recovery efficiency is lowered, resulting in consumption of a large amount of raw material air. Therefore, even if the amount of nitrogen used is reduced, the operation of the raw material air is similarly performed, and nitrogen of excess purity is supplied, thereby consuming the energy in vain.

On the other hand, for example, Patent Document 1 discloses a method of stabilizing the purity of nitrogen gas in a nitrogen gas generating apparatus using a PSA method, and using an appropriate amount of raw material air corresponding to the amount of nitrogen used. And it works. According to this method, focusing on the change in the oxygen concentration at the outlet of the adsorption tower, when the oxygen concentration at the outlet reaches the set oxygen concentration, the adsorption tower is switched, so that the half cycle time is automatically changed. Thereby, the amount of raw material air used can be reduced, so that power consumption can be reduced.

Advanced technical literature

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2005-270953

However, in the nitrogen generating apparatus of the above-described conventional example, the half cycle time is changed depending on the purity of the released nitrogen gas, and therefore, the effect of reducing the amount of raw material air used according to the amount of nitrogen used may not be appropriately obtained. . Further, since the half cycle time is automatically changed in accordance with a predetermined program in the entire region of the purity of nitrogen gas which can be generated during actual operation, the actual control becomes complicated and the stability of the operation is impaired.

Accordingly, it is an object of the present invention to provide a pressure swing adsorption type gas generating apparatus which can maintain a predetermined recovery efficiency and reduce the amount of raw material air when operating at a flow rate of less than the maximum generated product nitrogen gas, and can be The use condition is controlled by using the set value of the phase.

The pressure swing adsorption type gas generating apparatus of the present invention includes: a first adsorption tank filled with an adsorbent and a second adsorption tank; and a raw material air introduction flow path connected to the first adsorption tank and the second adsorption tank; a product tank for storing nitrogen gas separated from the raw material air in the adsorption tank and the second adsorption tank; an exhaust gas flow path from the first adsorption tank and the second adsorption tank; and the first adsorption tank and the second adsorption tank a pressure equalization flow path that communicates between the adsorption tanks; a product gas flow path between the first adsorption tank and the product tank, and between the second adsorption tank and the product tank; and a valve provided in each of the flow channels a product gas flow sensor for detecting a flow rate Lp of the product gas flowing out from the product tank to the outside; and a control device for controlling opening and closing of the respective valves; wherein the control device performs the two adsorption tanks Switching and repeatedly controlling the adsorption desorption operation after the pressure equalization step of opening the pressure equalization flow path, and by one of the first adsorption tank and the second adsorption tank The adsorption step is performed by the adsorbent, and the desorption step of desorbing the gas from the adsorbent is performed in the other adsorption tank.

In order to solve the above problems, the pressure swing adsorption type gas generating apparatus of the present invention is characterized in that the ratio of the generated amount R = Lp / is reduced according to the maximum generated amount Lm set to the maximum value of the product gas flow rate Lp. Lm is used to control the adsorption/desorption operation by periodically switching the adsorption/desorption cycle T, which is a period in which one cycle of the adsorption/desorption operation is continued.

According to the pressure swing adsorption type gas generating apparatus having the above configuration, when the operation is performed at the product gas flow rate Lp smaller than the maximum production amount Lm, the purity of the nitrogen gas can be maintained in an appropriate range, and the product gas flow rate Lp is stepwisely applied. The adsorption desorption cycle T is switched, and the high recovery efficiency can be maintained to reduce the amount of raw material air. Further, since the adsorption/desorption cycle T is set in stages based on the product gas flow rate Lp, the set value can be easily changed according to the use condition, and the energy-saving operation can be efficiently performed.

The present invention can adopt the form described below based on the above configuration.

In other words, the pressure swing adsorption type gas generating apparatus of the present invention may be configured to include a ratio setting unit for sequentially setting a plurality of generation amount ratios R _i for the generation amount ratio R in stages. a setting input value of =L _i /Lm (i = 0 to n; n is a positive integer) is held; and a period setting unit for correlating with each of the above-described generation amount ratios R _i for the adsorption desorption period T The set input value of the stage of the adsorption desorption period T _i is maintained; the control means is based on the flow rate Lp of the product gas detected by the product gas flow sensor, and is based on each of the above-described production amount ratios R _i The adsorption desorption operation T is controlled by the adsorption desorption cycle T selected in correspondence with the adsorption desorption cycle T _i .

Further, the above-described production amount ratio R _i and the value of the adsorption desorption period T _i are set according to the following conditions.

In the range of R _o =0, R _n =1, 0 < i < n, 0 < R _i <1 (where R _i <R _i+1 ), and

T _i >T _i+1 ;

The control device selects the adsorption desorption period T according to the following formula (1),

When R _i-1 <(R=Lp/Lm)≦R _i , T=T _i (1).

Further, the adsorption and desorption cycle is preferably set to T _i to produce an amount ratio R = Lp / Lm = when R _i, can maintain the desired nitrogen purity.

Further, it is preferable to include a raw material air tank for storing and supplying the raw material air, a compressor for compressing the air to supply the air to the raw material air tank, and a raw material for detecting the pressure P01 in the raw material air tank. In the air pressure sensor, the control device performs control for stopping the driving and stopping of the compressor based on the detection pressure P01 of the raw material air pressure sensor, thereby maintaining the detection pressure P01 at a predetermined value or more.

In this case, it is preferable to set the lower reference value Pt1 and the upper reference value Pth (Pt1 < Pth), and the control device performs control so as to drive the compressor to increase the detection pressure P01. When P01≧Pth, the compressor is stopped; during the process of stopping the compressor to decrease the detection pressure P01, the compressor is started to be driven when P01≦Pt1.

Hereinafter, the pressure swing adsorption type gas generating apparatus according to the embodiment of the present invention will be described in detail with reference to the drawings.

(Embodiment 1)

Fig. 1 is a schematic view showing the configuration of a nitrogen generating device according to a first embodiment of the present invention. This apparatus includes a first adsorption tank 1 and a second adsorption tank 2 filled with an oxygen adsorbent as a gas generating unit, and a product tank 3 for temporarily storing the generated product gas, that is, nitrogen gas, and supplying the nitrogen gas to the outside. Further, a raw material air inlet 4 for supplying the raw material air to the gas generating unit, and a product gas outlet 5 for supplying the nitrogen gas from the product tank 3 to the outside are provided.

The first adsorption valve (SV1), the second adsorption valve (SV2), the first exhaust valve (SV3), and the second row are provided in the pipes 6 and 7 that connect the first adsorption tank 1 and the second adsorption tank 2. A gas valve (SV4), two pressure equalizing valves (SV5), a first outlet valve (SV6), a second outlet valve (SV7), and a flow regulating valve 8.

The raw material air is introduced into the first adsorption valve (SV1) and the second adsorption valve (SV2) in each of the gas generation units. The first adsorption valve (SV1) is connected to the first adsorption tank 1 by a pipe 6, and the second adsorption valve (SV2) is connected to the second adsorption tank 2 by a pipe 7. The flow path indicated by the pipe 6 and the pipe 7 is connected to the exhaust port 9 via the first exhaust valve (SV3) and the second exhaust valve (SV4), respectively. The first adsorption tank 1 and the second adsorption tank 2 can communicate via two equalizing valves (SV5) provided above and below.

One of the three pipes led out from the first adsorption tank 1 is connected to the product tank 3 via the first outlet valve (SV6). One of the three pipes led out from the second adsorption tank 2 is connected to the product tank 3 via the second outlet valve (SV7). The first adsorption tank 1 and the second adsorption tank 2 are connected to each other via a flow rate adjusting valve 8 .

A raw material air pressure sensor P0 is disposed in the line connected to the raw material air inlet 4. The first adsorption tank pressure sensor P1 and the second adsorption tank pressure sensor P2 are provided in the first adsorption tank 1 and the second adsorption tank 2, respectively. A product tank pressure sensor P3 for detecting the pressure in the tank is provided in the product tank 3. In the flow path from the product tank 3 to the product gas outlet 5, a product gas flow sensor F for detecting the flow rate of the product gas flowing out of the product tank 3, and a pair of purity sensors as the product gas flowing out are provided. The oxygen concentration sensor OC for detecting the oxygen concentration in the product gas. In the following description, the pressure values detected by the raw material air pressure sensor P0, the first adsorption tank pressure sensor P1, the second adsorption tank pressure sensor P2, and the product tank pressure sensor P3 are used. Corresponding symbols P0, P1, P2, and P3 are indicated.

The output of each inductor is input to the control device 10. Further, the opening and closing operation of each valve is controlled by the valve drive signal supplied from the control device 10. The control device 10 sets various setting values by a normal operation of a CPU (Central Processing Unit), performs valve drive control, operation control based on output of each sensor, and the like, and omits illustrations related to electric wiring. . Fig. 1 shows a cycle control unit 11, a ratio setting unit 12, and a cycle setting unit 13 for maintaining the functions unique to the embodiment as elements included in the control device 10, and further indicates that it is useful to perform corresponding elements. The touch panel 14 is operated.

Next, the operation of the nitrogen generating device having the above configuration will be described with reference to Figs. 1 and 2 . In the first adsorption tank 1 and the second adsorption tank 2, the adsorption operation (supplying the compressed raw material air and adsorbing it by the adsorbent under high pressure) and the desorption operation (lowering the pressure to cause adsorption) The gas desorption of the adsorbent is alternately performed by switching the valves. In the following description, the step of performing the adsorption operation in the first adsorption tank 1 and performing the desorption operation in the second adsorption tank 2 is referred to as the A step, and the adsorption operation is performed in the second adsorption tank 2, and The step of performing the desorption operation in the adsorption tank 1 is referred to as the B step, and the step of opening the pressure equalization valve (SV5) to equalize the pressures of the two adsorption tanks is referred to as a C step (or referred to as a pressure equalization step). The C step is inserted between the two steps of the A step and the B step, while the steps A and B are alternately performed, and the operation of taking out nitrogen or oxygen is continuously performed.

Fig. 1 shows a state in which the first adsorption tank 1 is an adsorption step and the second adsorption tank 2 is in a desorption step, that is, step A. Since it is basically the same as the well-known steps, the description of the B step and the C step will be omitted. Among the lines connecting the grooves and the like, the portion indicated by the thick line means that the gas flows. In the figure, the hatching added to the valve indicates an open state, and the valve without a hatch is closed. Further, the hatching applied to each of the adsorption tanks 1, 2 and the product tank 3 indicates the state in which nitrogen gas is present.

Fig. 2 shows the pressure distribution and the operation timing in each part of each step. The curve indicated by P0 in Fig. 2 indicates the raw material air pressure supplied to the first adsorption valve (SV1) and the second adsorption valve (SV2). P1 to P3 respectively indicate pressure values obtained by the first adsorption tank pressure sensor P1, the second adsorption tank pressure sensor P2, and the product tank pressure sensor P3. SV1, SV2, SV3, SV4, SV5, SV6, and SV7 respectively indicate valve drive signals for opening and closing the corresponding valves. In the area where the hatching is added, each valve is in an open state due to the valve drive signal, and in other regions, each valve is in a closed state. The horizontal axis in the graph indicates time, and the steps are repeated in the order of the C step, the A step, the C step, the B step, and the C step in the direction of the time axis. The time indicated on the upper part of the symbols A to C is the duration of each step.

In step A shown in FIG. 2, the valve drive signals supplied to the first adsorption valve (SV1), the second exhaust valve (SV4), and the first outlet valve (SV6) are open signals, and the closed signal is supplied. To other valves. In the first adsorption tank 1, the pressurized raw material air is introduced into the bottom of the first adsorption tank 1, and the adsorption step is performed. As the raw material air pressure P0 rises, the first adsorption tank pressure P1 also rises. Accordingly, oxygen is adsorbed from the raw material air by the oxygen adsorbent, and the nitrogen gas flows out from the upper portion of the tank and is introduced into the product tank 3 via the outlet valve (SV6). As a result, the product tank pressure P3 rises.

The second adsorption tank 2 is depressurized via the second exhaust valve (SV4), and the second adsorption tank pressure P2 is rapidly lowered. At this time, the circulating nitrogen taken out from the top of the first adsorption tank 1 via the flow rate adjusting valve 8 is introduced into the top of the second adsorption tank 2. By these actions, oxygen is desorbed from the oxygen adsorbent and discharged.

In the pressure equalizing step of step C, the pressure equalizing valve (SV5) is opened and the other valves are closed. Therefore, the raw material air pressure P0 rises to the pressure supplied from the raw material air inlet 4. The first adsorption tank pressure P1 is lowered, the second adsorption tank pressure P2 is increased, and the pressures of the two adsorption tanks are equalized. The purpose of performing the pressure equalization step is to reduce the energy loss caused by the release of pressurized gas into the atmosphere when the self-adsorption step proceeds to the desorption step. That is, the pressure of the tank entering the desorption step is supplied to the tank entering the adsorption step, thereby recovering about half of the pressurized energy.

In the step B, the desorption step is performed in the first adsorption tank 1, and the adsorption step is performed in the second adsorption tank 2. The operation at this time is symmetrical with the operation in the step A, and the operation in the first adsorption tank 1 and the second adsorption tank 2 is opposite to the step A. That is, in step B, the open signal is supplied to the second adsorption valve (SV2), the first exhaust valve (SV3), and the second outlet valve (SV7), and the closing signal is supplied to the other valves, and the rest is Step A performs the same operation, and thus the detailed description is omitted.

As described above, the adsorption step and the desorption step of the inclusion pressure equalization step are alternately performed in the first adsorption tank 1 and the second adsorption tank 2, whereby nitrogen gas is continuously generated. Thus, the time during which one cycle of the adsorption desorption operation by the pressure equalization C step and one of the A step or the B step is continued is defined as the adsorption desorption period T definition. The nitrogen generating device in the present embodiment is configured to change the adsorption/desorption cycle T in accordance with the state of use of the generated nitrogen gas.

Here, the state of use of nitrogen is represented by the product gas flow rate Lp, which is obtained by detecting the flow rate of the product gas flowing out of the product tank 3 by the flow sensor F. Further, the maximum generated amount Lm set to the maximum value of the product gas flow rate Lp is defined as the rated generation amount.

The reduced production amount ratio R with respect to the maximum generation amount Lm is defined as R = Lp / Lm.

In the present embodiment, when the operation is performed at a product gas flow rate Lp smaller than the maximum (rated) production amount Lm, the adsorption desorption cycle is performed according to the generation amount ratio R = Lp / Lm by maintaining the purity of the nitrogen gas within a predetermined range. T is switched stepwise to control the adsorption desorption time at which the high recovery efficiency is maintained and the amount of raw material air is reduced.

Hereinafter, a specific example of the adsorption desorption time control will be described. First, the ratio setting unit 12 shown in FIG. 1 holds a plurality of generation amount ratios R _i =L _i /Lm (i=0 to n; n is a positive integer) which are set stepwise with respect to the generation amount ratio R. Set the input value. The ratio of the amount of production R is a ratio of the result of the decrease with respect to the maximum amount of production Lm, and therefore, R ≦ 1 . Further, the period setting unit 13 holds the set input value of the adsorption desorption period T _{i which} is set stepwise for each of the generation amount ratios R _i for the adsorption desorption period. These settings are entered and set by the operation of the touch panel 14.

The cycle control unit 11 corresponds to the flow rate Lp of the product gas (production amount ratio R=Lp/Lm), and the respective adsorption amount ratio R _i held by the ratio setting unit 12 and the adsorption desorption period T held by the cycle setting unit 13 The correspondence relationship of _i is selected to adsorb the desorption period T, and the adsorption desorption operation is controlled according to the selected adsorption desorption period T.

The above-mentioned set values used in the above control are adjusted according to the following conditions.

R _o =0, R _n =1, and

In the range of 0<i<n, 0<R _i <1 (where R _i <R _i+1 ), and

T _i >T _i+1

Further, the adsorption desorption cycle T is selected in accordance with the following (number 1).

When R _i-1 <(R=Lp/Lm)≦R _i , T=T _i (1)

Further, when the production amount ratio R = Lp / Lm = R _i , it is preferred to set the adsorption desorption period T _{i in} such a manner as to maintain the desired product gas purity.

Fig. 3 is a table showing the form of the setting of the flow rate operation program which is the basis of the adsorption desorption time control as described above. STEP1 to STEP5, which are arranged side by side in the vertical direction, indicate segments corresponding to respective set values of the amount-of-production ratio R _i . The ratio of the amount of production R _i (0% to 100%) expressed in percentage, the adsorption desorption period T _i (seconds), and the set flow rate are shown in each segment. In this example, n=5.

For example, in STEP 1, i=5, the production amount ratio R ₅ is 100%. Therefore, the set flow rate 100.0 Nm ³ /h described in the set flow rate display column is the maximum generated amount Lm which is the rated generation amount. In this section, the adsorption desorption period T ₅ is 60.0 seconds, which corresponds to the lower limit of the adsorption desorption period T.

Further, STEP2 is i=4, the generation amount ratio R ₄ is 75%, and the set flow rate is set to a section of 75.0 Nm ³ /h. In this section, the adsorption desorption period T ₄ was 90.0 seconds. According to the above (number 1), in the range of R ₄ < (R = Lp / Lm) ≦ R _n , that is, in the range where the amount-of-production ratio R exceeds 75% and is 100% or less, the adsorption desorption period T is selected. 60.0 seconds.

Similarly, in the range where the production amount ratio R exceeds 50% and is 75% or less, the adsorption desorption period T is selected to be 90.0 seconds. In the range where the production amount ratio R exceeds 25% and is 50% or less, the adsorption desorption period T is selected to be 120.0 seconds. In the range where the production amount ratio R exceeds 0% and is 25% or less, the adsorption desorption period T is selected to be 150.0 seconds.

As described above, according to the nitrogen generating apparatus of the present embodiment, when the gas is operated at a product gas flow rate Lp smaller than the maximum amount of production Lm, the adsorption desorption time is performed in accordance with the product gas flow rate Lp by maintaining the purity of the nitrogen gas. Switching in stages ensures high recovery efficiency while reducing the amount of feed air. The section in which the amount ratio R _i is generated and the corresponding adsorption desorption period T _i can be changed in accordance with the set value, so that the energy-saving operation can be realized in an optimum state according to the situation at the time of practical use.

4 and 5 show the effects produced by using the nitrogen gas generating apparatus of the present embodiment. Fig. 4 shows numerical values obtained by comparing the raw material air consumption rates in the case where the adsorption/desorption cycle T is set to a fixed standard operation and the operation based on the present embodiment set as shown in Fig. 3 . Fig. 5 is a diagram showing the table of Fig. 4 in a graph form.

(Embodiment 2)

Fig. 6 is a schematic view showing the configuration of a nitrogen generating device in the second embodiment of the present invention. This apparatus basically has the same configuration as that of the apparatus of the first embodiment shown in Fig. 1. Therefore, the same elements are denoted by the same reference numerals, and the description of the repetition is simplified.

In the apparatus of the first embodiment, the raw material air supplied from the outside of the nitrogen generating device is received. In contrast, in the present embodiment, the air introduced from the raw material air inlet 4 and passing through the air filter 15 is supplied to the compressor 16 . After being compressed (for example, using an oil-free scroll compressor), it is supplied as raw material air.

The raw material air is temporarily stored in the raw material air tank 17 after being compressed by the compressor 16, and then supplied to the first adsorption tank 1 or the second adsorption tank 2. A raw material air pressure sensor P01 that detects the pressure in the tank is provided in the raw material air tank 17. The pressure value detected by the raw material air pressure sensor P01 is indicated by the same symbol P01.

The compressor drive control unit 18 is provided in the control device 10. The compressor drive control unit 18 selects the drive (stop start control) by selecting the drive and stop of the compressor 16 based on the magnitude of the detected pressure P01 of the raw material air pressure sensor P01. That is, when the detected pressure P01 is P01 < Pt with respect to the predetermined reference value Pt, the compressor 16 is driven, and when P01 ≧ Pt, the compressor 16 is stopped.

However, actually, in order to ensure the stability of the operation, control corresponding to the history of the detection pressure P01 is performed. That is, the lower reference value Pt1 and the upper reference value Pth (Pt1 < Pth) are set. Then, in the process of driving the compressor 16 to increase the detected pressure P01, the compressor 16 is stopped when P01 ≧ Pth. On the other hand, in the process of stopping the compressor 16 and decreasing the detection pressure P01, the compressor 16 is started to be driven when P01 ≦ Pt1. Thereby, it is avoided to frequently start and stop the compressor 16. The lower reference value Pt1 and the upper reference value Pth are set to, for example, 0.75 MP and 0.85 MP, respectively.

In this manner, the built-in compressor 16 is started and stopped based on the pressure P01 of the raw material air tank 17, whereby the power consumption of the compressor 16 can be reduced. Moreover, the life of the compressor 16 can be greatly extended. As described above, the power consumption can be effectively reduced by the start-stop control of the compressor 16. As in the first embodiment, it is necessary to reduce the adsorption/desorption cycle T to reduce the material air consumption rate. .

That is, the flow rate of the compressed raw material air supplied from the raw material air tank 17 varies depending on the state of use of the product gas, that is, according to the product gas flow rate Lp (nitrogen release amount). If the product gas flow rate Lp is small, the flow rate from the raw material air tank 17 is small.

Here, when the compressor 16 is continuously operated, when the flow rate from the raw material air tank 17 is small, even if the pressure P01 of the raw material air tank 17 has reached the necessary level, the compressor 16 is driven in vain. . In this case, even if the compressor 16 is stopped when P01 ≧ Pt as described above, the adsorption/desorption operation in the first adsorption tank 1 and the second adsorption tank 2 is not affected. Therefore, if the compressor 16 is stopped, the power consumption can be reduced. Further, by adopting a configuration in which the adsorption desorption cycle T is changed to reduce the raw material air consumption rate, the stop time of the compressor 16 can be extended, and the power consumption can be more effectively reduced.

Fig. 7 shows an effect of reducing the power consumption of the compressor by using the nitrogen gas generating apparatus of the present embodiment. As can be seen from Fig. 7, when the compressor is started and stopped by the present embodiment, compared with the case where the compressor is continuously operated by the conventional standard operation method, it can be remarkably reduced according to the amount of released air. Small power consumption.

Industrial availability

According to the pressure swing adsorption type gas generating apparatus of the present invention, the power consumption can be reduced in accordance with the increase or decrease of the flow rate of the consumed product gas, so that it can be effectively used as a system for supplying nitrogen gas.

1. . . First adsorption tank

2. . . Second adsorption tank

3. . . Product slot

4. . . Raw material air inlet

5. . . Product gas outlet

6, 7. . . Piping

8. . . Flow regulating valve

9. . . exhaust vent

10. . . Control device

11. . . Cycle control department

12. . . Ratio setting unit

13‧‧‧Cycle setting department

14‧‧‧Touch panel

15‧‧‧Air filter

16‧‧‧Compressor

17‧‧‧Material air tank

18‧‧‧Compressor Drive Control Department

P0, P01‧‧‧ raw material air pressure sensor

P1‧‧‧1st adsorption tank pressure sensor

P2‧‧‧2nd adsorption tank pressure sensor

P3‧‧‧Product tank pressure sensor

F‧‧‧Product gas flow sensor

OC‧‧‧Oxygen concentration sensor

SV1‧‧‧1st adsorption valve

SV2‧‧‧2nd adsorption valve

SV3‧‧‧1st exhaust valve

SV4‧‧‧2nd exhaust valve

SV5‧‧‧pressure equalization valve

SV6‧‧‧1st exit valve

SV7‧‧‧2nd exit valve

Fig. 1 is a schematic view showing a pressure swing adsorption type nitrogen generating apparatus in accordance with a first embodiment of the present invention.

Fig. 2 is a view showing pressure changes and operation timings in the operation of the nitrogen generating device of Fig. 1.

Fig. 3 is a table showing the setting of the flow rate operation program which is the basis of the adsorption/desorption time control in the above-described nitrogen gas generator.

Fig. 4 is a table showing the effect of reducing the air consumption rate of the raw material by using the above nitrogen generating device.

Fig. 5 is a diagram showing the effect of Fig. 4 in a graph.

Fig. 6 is a schematic view showing a pressure swing adsorption type nitrogen generating apparatus according to a second embodiment of the present invention.

Fig. 7 is a view showing an effect of reducing the power consumption of the compressor by using the above nitrogen generating device.

1. . . First adsorption tank

2. . . Second adsorption tank

3. . . Product slot

4. . . Raw material air inlet

5. . . Product gas outlet

6, 7. . . Piping

8. . . Flow regulating valve

9. . . exhaust vent

10. . . Control device

11. . . Cycle control department

12. . . Ratio setting unit

13. . . Cycle setting unit

14. . . Touch panel

P0, P01. . . Raw material air pressure sensor

P1. . . 1st adsorption tank pressure sensor

P2. . . 2nd adsorption tank pressure sensor

P3. . . Product tank pressure sensor

F. . . Product gas flow sensor

OC. . . Oxygen concentration sensor

SV1. . . First adsorption valve

SV2. . . Second adsorption valve

SV3. . . First exhaust valve

SV4. . . Second exhaust valve

SV5. . . Pressure equalization valve

SV6. . . First outlet valve

SV7. . . 2nd outlet valve

Claims (4)

A pressure swing adsorption type gas generating device comprising: a first adsorption tank filled with an adsorbent and a second adsorption tank; and a raw material air introduction flow path connected to the first adsorption tank and the second adsorption tank; a product tank for storing nitrogen gas separated from the raw material air in the adsorption tank and the second adsorption tank; an exhaust gas flow path from the first adsorption tank and the second adsorption tank; and the first adsorption tank and the second adsorption tank a flow path for equalizing pressure that communicates between the adsorption tanks; a product gas flow path between the first adsorption tank and the product tank, and between the second adsorption tank and the product tank; a valve disposed in each of the flow paths a product gas flow sensor for detecting a flow rate Lp of the product gas flowing out from the product tank; and a control device for controlling opening and closing of the respective valves; the control device performs the two adsorption tanks The adsorption/desorption operation is repeatedly controlled by switching, and the adsorption and desorption operation is performed after the pressure equalization step of opening the pressure equalization flow path, and the adsorbent is used in one of the first adsorption tank and the second adsorption tank And the adsorption step is carried out while in another adsorption tank a desorption step of desorbing a gas from the adsorbent, the pressure swing adsorption gas generating device characterized in that the definition of the maximum generated amount Lm with respect to the maximum value of the gas flow rate Lp set to the product has been reduced The production amount ratio R=Lp/Lm; further comprising: a ratio setting unit for setting a plurality of generation amount ratios R _i =L _i /Lm (i=0~) for the generation amount ratio R in stages n; n is a positive integer) setting input value is maintained; and a period setting unit for the duration of one cycle of the adsorption desorption operation, that is, the adsorption desorption period T, for ratio R _i to each of the production amounts The set input value corresponding to the stage of the adsorption desorption period T _i is maintained; the value of the production amount R _i and the value of the adsorption desorption period T _i are set according to the following conditions: R _o =0 , in the range of R _n =1,0<i<n, 0<R _i <1 (where R _i <R _i+1 ), and T _i >T _i+1 ; the control device is based on the gas from the product The flow rate Lp of the product gas detected by the flow sensor is selected according to the following formula (1): when R _i-1 < (R = Lp / Lm) ≦ R _i , T = T _i (1); The adsorption desorption operation is controlled according to the selected adsorption desorption period T. The scope of the patent application pressure swing adsorption gas generating apparatus as item 1, wherein: the period T _i based adsorption and desorption when the generation amount is set to the ratio R = Lp / Lm = when R _i, can maintain the desired nitrogen purity. The pressure swing adsorption gas generating device of claim 1, wherein: a raw material air tank for storing and supplying the raw material air; a compressor for compressing and supplying the air to the raw material air tank; and a raw material air pressure sensor for detecting the pressure P01 in the raw material air tank; the control device is performed Control: The compressor is repeatedly driven and stopped according to the detection pressure P01 of the raw material air pressure sensor, thereby maintaining the detection pressure P01 at a predetermined value or more. A pressure swing adsorption type gas generating apparatus according to claim 3, wherein: the lower reference value Ptl and the upper reference value Pth (Ptl < Pth) are set, and the control device performs control such that the compressor is In the process of driving to increase the detection pressure P01, the compressor is stopped when P01≧Pth, and the compressor is started to be driven when P01≦Ptl is stopped while the compressor is stopped to decrease the detection pressure P01.