JPH0647547Y2 - Pressure swing type mixed gas separator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field of the Invention The present invention relates to a mixed gas in which two or more kinds of gases are mixed, as in the case of separating steam from compressed air containing steam and taking out dried air. TECHNICAL FIELD The present invention relates to an apparatus for separating one kind or two or more kinds of gases, and in particular, a separation step of separating gases by two separation cylinders filled with a separating agent and a part of the separated gas are used to remove the gas from the separating agent The present invention relates to a pressure swing type mixed gas separation device configured to alternately perform a regeneration process.

Problems to be Solved by the Related Art and Invention The pressure swing type mixed gas separation apparatus is designed to reduce the pressure of a part of the treated gas discharged from one separation cylinder and supply it to the other separation cylinder through a throttle. Although the separating agent in the separation cylinder is regenerated, in the conventional device, when the load is small, a fixed orifice is used as a throttle, which is large enough to secure the required regeneration gas at maximum load. However, the same amount of regeneration gas as that at the time of maximum load is consumed, and the treated gas and eventually the supply gas are wasted, resulting in a low operating efficiency.

Means for Solving the Problem As a means for solving such a problem, the present invention has a restrictor having two ports connected to each separation cylinder separately from a high pressure side port to a low pressure side port. While reducing the pressure set to the port and alternately supplying air, and making it a bidirectional pressure reducing valve with an orifice installed in each port,
Regeneration flow rate calculating means for calculating the minimum flow rate of the processed gas required for regeneration of the separating agent in the separation cylinder based on the pressure, temperature and flow rate of the untreated mixed gas supplied to the separation cylinder, and Pressure calculation means that calculates the pressure of each port required to obtain the calculated flow rate value based on the calculated flow rate value and the set value of the distribution area of each orifice, and the setting of each port corresponding to each calculated pressure value The configuration includes a control unit for controlling the pressure and a correction unit for individually correcting the set value of the opening area of each orifice.

Action and effect of the device Once the operation is started, it is necessary to regenerate the separating agent in the separation cylinder depending on the pressure, temperature and flow rate of the untreated mixed gas supplied to the separation cylinder, that is, the load applied to the separation cylinder. The minimum treated gas flow rate to be calculated is calculated by the regeneration flow rate calculation means, and then the calculated value of the regeneration flow rate and the set value of the distribution area of each orifice provided at the port of the bidirectional pressure reducing valve. Based on the above, the pressure of each port required to obtain the regeneration flow rate value is calculated by the pressure calculation means. Then, the calculated pressure value is set to the set pressure of each port by the control means, and the pressure of each port is maintained at the calculated pressure value, so that the required amount of regenerated gas calculated from each port is obtained. This results in no waste of treated gas and hence of supply gas and efficient operation is expected.

Here, in this type of separation device, it is common to apply the same load to each separation cylinder, and each port of the bidirectional pressure reducing valve for obtaining regenerated gas has an orifice with the same distribution area. Will be installed. If so, by calculating the pressure based on the setting value of the common distribution area of both orifices, and controlling each port to the same pressure,
Although the same regeneration flow rate should be obtained for both, the actual distribution area of the orifice may differ from the set value due to processing accuracy and gas circulation direction, and the actual circulation area of both orifices may differ. If the port pressure is controlled to be the same even though the area is different, there will be a difference in the regeneration flow rate from each port. Then, the regeneration capacities of the two separation cylinders are different, and the conditions such as the concentration and flow rate of the treated gas discharged from the discharge port fluctuate each time the separation cylinders are replaced. In order to avoid this, it has been extremely troublesome to perform additional machining on the orifice to adjust the distribution area of the orifice until it becomes equal while measuring the flow rate from each port. It was.

Therefore, in the present invention, the setting value of the distribution area of the orifice is separately corrected by the correction means, and the pressure of each port is calculated based on each corrected setting value. The pressure value is set to the set pressure. For example, if the actual distribution area of the orifice of one port is smaller than that of the orifice of the other port, if the pressure of both ports is controlled to the same value, the actual distribution area of the orifice will be smaller. The regeneration flow rate flowing out of the port is smaller than that of the other port, but either correct the set value of the distribution area of the orifice of one port to a smaller value, or change the set value of the distribution area of the orifice of the other port. With a large correction, the set pressure of one port is made relatively larger than that of the other port, and it becomes possible to cancel the difference in the actual distribution area of the orifice described above and obtain the same regeneration flow rate. .

That is, according to the present invention, the treated gas used for regeneration can be suppressed to the minimum necessary and can be operated efficiently, and the actual distribution of the orifice of both ports of the bidirectional pressure reducing valve can be achieved. If there is a difference in area, first use a correction means to numerically correct the set value of the distribution area of the orifice, and after that, the set pressure of the port will be set to cancel the difference in the actual distribution area. It is changed so that the same regeneration flow rate can always be obtained in both directions. As a result, both separation cylinders are regenerated with the same regeneration capacity, and the treated gas under the same conditions can be stably obtained from both separation cylinders. Moreover, the adjustment work is extremely simple because the correction means only numerically corrects the distribution area of the orifice as described above. Further, even when the distribution area of the orifice is changed over time due to the attachment of the separating agent or the like, it can be easily corrected. Further, it is possible to cope with the case where the loads of both separation cylinders are different and the regeneration flow rate is intentionally made different.

Embodiment An embodiment in which the present invention is applied to a dehumidifying device for pressurized air will be described below with reference to the accompanying drawings.

FIG. 1 shows a circuit diagram of the present embodiment, in which the high-pressure and high-humidity untreated air flowing in from the inlet 9 is opened by opening / closing valves 1a and 2a, and the first separating cylinder 6a filled with an adsorbent 10 such as silica gel. When passing through the inside, water vapor is adsorbed on the adsorbent 10 and separated, and the dried air is filtered by passing through the filter 5a and discharged from the discharge port 8 while the opening / closing valve 4b is opened to perform the second separation. The cylinder 6b communicates with the atmosphere from the discharge port 7, and a part of the low-humidity air discharged from the first separation cylinder 6a rapidly expands through the restrictor 13 so that the humidity is further reduced to the second separation. The water that has flowed into the cylinder 6b and has been adsorbed in the adsorption step of the previous step is deprived of the adsorbent 10 and dried to be regenerated, and then discharged from the discharge port 7. After a certain period of time, the open / close valve 4b is closed and the open / close valve 3b is opened, so that the treated high-pressure air is filled in the second separation cylinder 6b to increase the pressure, and then,
The open / close valves 1a and 2a are closed, the open / close valves 1b and 2b are opened, untreated high-pressure air flows into the second separation cylinder 6b, and after the switching, the open / close valve 4a is opened and remains in the first separation cylinder 6a. High-pressure air is exhausted 7
The air that has been discharged from the second separation cylinder 6b and in which the regenerated adsorbent 10 adsorbs water vapor and is dried is discharged from the discharge port 8 through the filter 5b, and a part of the dry air is squeezed.
The first separating cylinder is further dried by expanding through the first separating cylinder.
It flows into the inside of 6a, removes water from the adsorbent 10 therein, and is dried and regenerated. In this way, the adsorption and regeneration steps are alternately performed by the first separation cylinder 6a and the second separation cylinder 6b, and dry air obtained by removing moisture from humid air can be continuously obtained.

The above description is a conventionally known pressure swing dehumidifier, but in the present embodiment, the throttle 13 is a bidirectional pressure reducing valve which will be described later in detail.
Is provided with a control device 14 for supplying a control signal, and a pressure gauge 15, a thermometer 16 and a flow meter 17 are attached to the inlet 9 of the untreated air, and the measured values thereof are the control device.
It is supposed to be entered in 14. Further, an external compensator 18 for compensating the flow area of the orifice described later in detail is also connected to the controller 14.

The above-described bidirectional pressure reducing valve 13 has the structure shown in FIG. 2, and the first port 20a is connected to the first separating cylinder 6a and the second port 20b is connected to the first separating cylinder 6a.
Are connected to the second separating cylinder 6b respectively, and are connected to the respective ports 20a, 20b,
The orifices 34a and 34b having the same distribution area are attached. When the first separation cylinder 6a is in the adsorption process and the second separation cylinder 6b is in the regeneration process, the pressure of the first port 20a is the second
Since it is higher than the pressure of port 20b, spool 22 of switching valve 21
Is pushed down and the pressure of the second port 20b is transmitted to the feed back chamber 23, and conversely, when the first separation cylinder 6a is in the regeneration process and the second separation cylinder 6b is in the adsorption process, the second port Since the pressure of 20b is higher than the pressure of the first port 20a, the spool 22 of the switching valve 21 is pushed up and the pressure of the first port 20a is transmitted to the feed back chamber 23. The pressure reduction control from the higher pressure side to the lower pressure side is automatically performed according to the pressure level relationship between the two ports 20b.

Now, assuming that the pressure at the first port 20a is higher than the pressure at the second port 20b, the controller 24 compares the control signal from the controller 14 and the feedback signal from the pressure sensor 25, which will be described later, in detail, and compares the voltage element flapper. The applied voltage to 26 is controlled, and when the control signal is larger than the feedback signal (pressure signal of the second port 20b), the applied voltage increases and the tip of the piezoelectric element flap 26 is displaced downward, closing the nozzle 27. Try to. Here, the compressed air supplied from the pilot pressure supply port 28 passes through the orifice 29 and flows into the pilot chamber 30, but when the nozzle 27 is closed by the piezoelectric element flap 26, the pressure in the pilot chamber 30 rises. As the diaphragm 31 is pushed down together with the valve rod 32 and the main valve 33 is opened, air is supplied from the first port 20a to the second port 20b and the pressure of the second port 20b rises. Then, the pressure of the feed back chamber 23 between the two diaphragms 31 and 34 increases, the feed back signal from the pressure sensor 25 increases, the difference from the control signal decreases, and the displacement of the piezoelectric element flap 26 is reduced. Since the nozzle 27 is opened and the pilot pressure is reduced, the diaphragm 31 is pushed up together with the valve rod 32 and the main valve 33 is closed. By repeating the above operation, the secondary side, that is, the second
The pressure on the port 20b side is maintained at a substantially constant pressure corresponding to the control signal from the control device 14, and the control pressure and the orifice
It flows out after being restricted to a constant flow rate determined by the distribution area of 34b. When the pressure on the second port 20b side becomes high, the same operation as described above is performed by switching the switching valve 21, and the pressure on the first port 20a side is maintained at the pressure corresponding to the control signal from the control device 14. The flow rate is controlled to a constant flow rate determined by the control pressure and the circulation area of the orifice 34a, and then flows out.

Next, the configuration of the control device 14 described above will be described based on the flow chart of FIG. As described above, the purpose of the present invention is to minimize the amount of the regenerating air when using a part of the dry air obtained in one of the separation cylinders 6a and 6b for regenerating the other. Especially.

When the volumetric flow rate of untreated air in the separation tubes 6a, 6b flows in, what percentage of that is used for regeneration depends on the target dryness, that is, the target atmospheric pressure dew point and the inlet air temperature at that time. different. For example, the lower the target atmospheric pressure dew point and the higher the temperature of the inflowing air, the larger amount of air is required for regeneration. Therefore, the reproduction volume ratio depending on the conditions of the target atmospheric pressure dew point and the intake air temperature, that is, the ratio Rp of the volume of the air required for the reproduction to the volume of the inflow air is stored in the control device 14 as a data table or an arithmetic expression. Every time, the regeneration volume ratio Rp is calculated from the preset target atmospheric pressure dew point Dp and the inlet air temperature Ti measured by the thermometer 16.

Then, the inflow volumetric flow rate is obtained from the measured values of the flowmeter 17 and the pressure gauge 15, and by multiplying it by the above regeneration volume ratio Rp, the flow rate Qp required for regeneration is calculated. The regeneration flow rate Qp is a flow rate required to flow out from the first port 20a and the second port 20b of the bidirectional pressure reducing valve 13 described above.
The regeneration flow rate Qp is determined by the pressure of each port 20a, 20b and the distribution area of the orifices 34a, 34b, so that the preset value Sp of the distribution area of the orifice is input in advance. The pressure of the ports 20a, 20b required to obtain the regeneration flow rate Qp is calculated.

Then, by inputting the calculated pressure value as the control signal to the controller 24 of the bidirectional pressure reducing valve 13, the ports 20a and 20b are maintained at the pressure corresponding to the control signal as described above, and the calculation is performed. The required regeneration flow rate Qp thus obtained is obtained.

Here, the ORIFUS 34 attached to both ports 20a and 20b
Since a and 34b have the same distribution area, each port
If 20a and 20b are controlled to the same pressure, the same regeneration flow rate should be obtained for both, but the actual flow area of orifices 34a and 34b differs from the set value due to processing accuracy and gas flow direction problems. In many cases, they are different from each other. That is, if the pressures of the ports 20a and 20b are controlled to be the same although the actual distribution areas of the orifices 34a and 34b are different, there will be a difference in the regeneration flow rates from the ports 20a and 20b.
Then, the regeneration capacities of the two separation cylinders 6a and 6b are different, and the dew point and flow rate of the dry air at the discharge port 8 fluctuate every time the dehumidification separation cylinders 6a and 6b are replaced.

Therefore, the controller 14 is connected to an external compensator 18 for compensating the preset value Sp of the distribution area of the orifice. The external compensator 18 is preferably a DIP SW (binary counter type switch) as shown in FIG. 4, for example, and two external compensators 18 are provided corresponding to each orifice 34a, 34b. As shown in, when the correction values α and β are input from the DIP SWs 18, the controller 14 sets the set values of the distribution areas of the orifices 34a and 34b as Spa = Sp + α and S, respectively.
It is corrected to pb = Sp + β. Here, for α and β, as shown in FIG. 5, the 8th digit switch of DIP SW13 is turned ON / OF.
Operate F to select +-, and switch from 1 digit to 7 digits ~
You can enter a value between -127 and +127 by turning ON and OFF respectively.

Then, based on the corrected distribution areas Spa and Spb of the orifices 34a and 34b described above, the pressures Ppa and Ppb of the ports 20a and 20b necessary to obtain the regeneration flow rate Qp are respectively calculated, and both are calculated as control signals. It is input to the controller 24 of the direct pressure reducing valve 13, and the ports 20a and 20b are maintained at the pressures corresponding to the control signals Ppa and Ppb, respectively. For example, if the actual distribution area of the orifice 34a of the first port 20a is smaller than the distribution area of the orifice 34b of the second port 20b, both ports 20a
If the pressures of a and 20b are controlled to the same value, the first port 20a
The regeneration flow rate flowing out from the side is smaller than that on the side of the second port 20b, but the set value of the distribution area of the orifice 34a of the first port 20a is corrected to a smaller value, or the orifice of the orifice 34b of the second port 20b is corrected. When the set value of the distribution area is largely corrected, the control pressure of the first port 20a is set to be relatively larger than the control pressure of the second port 20b, and the difference in the actual distribution area of the orifices 34a and 34b described above is offset. It is possible to obtain the same regeneration flow rate. In practice, the flow rate meter may measure the regeneration flow rates of the first and second ports 20a and 20b, and the correction values α and β may be input while changing them so that both measurement values are the same.

That is, if there is a difference in the actual distribution area of the orifices 34a, 34b of both ports 20a, 20b, first the external compensator 18
If the set values of the distribution areas of the orifices 34a, 34b are numerically corrected using, the control pressure of the ports 20a, 20b will be changed to cancel the difference between the actual distribution areas, and the bidirectional It is possible to obtain the same regeneration flow rate. As a result, both separation cylinders 6a and 6b are regenerated with the same regeneration capacity, and dry air having the same dew point and flow rate can be stably obtained from both separation cylinders 6a and 6b. Moreover, the adjustment work is extremely simple because the correction values α and β are only input from the external corrector 18 as described above. Also, due to the adhesion of the adsorbent 10 or the like, the orifices 34a, 3
Even if the distribution area of 4b changes over time, it can be easily corrected. Further, it is possible to cope with the case where the loads of the both separation cylinders 6a and 6b are different and it is desired to intentionally make a difference in the regeneration flow rate.

As is clear from the above description, the part that calculates the regeneration flow rate Qp from the target atmospheric pressure dew point Dp, the inlet air temperature Ti, the inlet air pressure Pi and the inlet air flow rate Qi of the control device 14 of the present embodiment is the regeneration flow rate of the present invention. The calculation means includes the regeneration flow rate Qp of the control device 14 of the present embodiment and the corrected distribution areas Spa and Spb of the orifice to control pressures Ppa and Pp.
The part for calculating pb corresponds to the pressure calculation means of the present invention, the controller 24 of the present embodiment corresponds to the control means of the present invention, and the external compensator 18 of the present embodiment corresponds to the correction means of the present invention.

[Brief description of drawings]

FIG. 1 is a circuit diagram of an embodiment of the present invention, FIG. 2 is a sectional view of the bidirectional pressure reducing valve, FIG. 3 is a flow chart showing the operation of the control device, and FIG. 4 is an example of an external compensator. Front view of the
FIG. 5 is a diagram for explaining the operation. 1a, 1b, 2a, 2b, 3a, 3b, 4a, 4b: open / close valve, 6a, 6b: separating cylinder, 7: outlet, 8: outlet, 9: inlet, 10: separating agent, 13: bidirectional Pressure reducing valve, 14: control device, 15: pressure gauge, 16: thermometer, 17:
Flowmeter, 18: External compensator, 20a, 20b: Port, 21: Switching valve, 22: Spool, 23: Feed back chamber, 24: Controller, 25: Pressure sensor, 26: Piezo element flapper, 2
7: Nozzle, 28: Pilot pressure supply port, 29: Orifice, 3
0: Pilot chamber, 31, 34: Diaphragm, 33: Main valve, 34
a, 34b: Orihuis

Claims (1)

[Scope of utility model registration request] 1. A two or more separation cylinders filled with a separating agent such as an adsorbent or an absorbent are provided, and an untreated mixed gas is supplied to one of the separation cylinders at a high pressure to produce one or more kinds of gas. And a separation step of discharging the treated gas separated by adsorbing or absorbing the separating agent from the discharge port, and reducing the pressure by passing a part of the treated gas discharged from the other separating cylinder through a throttle. A pressure for alternately performing a regeneration step of removing the gas that has been supplied and adsorbed or absorbed by the separating agent from the separating agent and discharging from the outlet in the two separating cylinders at regular intervals. In the swing type mixed gas separation device, the throttles are alternately reduced in pressure to a pressure set from the high pressure side port to the low pressure side port having two ports respectively connected to the respective separation cylinders. And before A bi-directional pressure reducing valve is provided with an orifice in each port, and it is necessary to regenerate the separating agent in the separation cylinder based on the pressure, temperature and flow rate of the untreated mixed gas supplied to the separation cylinder. Regeneration flow rate calculating means for calculating the minimum treated gas flow rate, and the pressure of each port required to obtain the calculated flow rate value based on the calculated flow rate value and the set value of the flow area of each orifice. Pressure control means for controlling the set pressure of each port corresponding to each calculated pressure value, and correction means for individually correcting the set value of the opening area of each orifice. Pressure swing type mixed gas separation device characterized by