JP2014004521A - High-pressure dry gas producing system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dry gas producing method that can remove water in a gas without substantially losing a gas component.SOLUTION: The dry gas producing method uses a dehumidifier that removes water in a gas, a gas liquid separation device that removes a liquid component in the gas, and means for increasing a pressure of the gas. The method increases a pressure of a gas containing water, supplies the gas to the dehumidifier, and takes out a dry gas from which the water is removed. In addition, the method mixes a humidified gas discharged from the dehumidifier with a raw material gas, and can supply the mixture gas to the dehumidifier again.

Description

  The present invention relates to a high-pressure dry gas production system capable of obtaining a high-pressure dry gas by removing water from a gas containing water, and particularly compressed without losing gas components other than water. The present invention relates to a high-pressure dry gas production system for producing dry gas.

  Conventionally, when various gases are compressed and used in the industrial field, moisture (water vapor) in the gas may be condensed and liquefied, which may cause damage to gas-using equipment. Therefore, when such compressed gas is used, it is generally used by removing moisture in the gas by some method. For example, Patent Document 1 discloses a technique relating to a method for generating dry air or nitrogen in order to operate an instrumentation device normally.

  On the other hand, as a device for separating and removing moisture in the gas, for example, a separation membrane method and a PSA (Pressure Swing Adsorption) method are known and used in the industrial field.

JP 63-182019 Patent 4521373

  However, in the membrane separation system, gas is lost because other useful gases are also permeated when moisture is excluded. Further, when the product drying gas is used as a purge gas in order to improve the dehumidifying efficiency, a loss of gas is similarly generated. Also in the PSA system, a portion of the dry gas is used as a purge gas in order to desorb water adsorbed on the adsorbent, resulting in gas loss.

  This invention is made | formed in view of the said problem, The objective is to provide the method of manufacturing compressed dry gas, without losing components other than a water | moisture content from the gas containing a water | moisture content.

The method for producing the compressed dry gas in the present invention for achieving the above object is as follows:
1. A dry gas production method for obtaining a dry gas having a reduced water vapor concentration from a source gas containing moisture, comprising at least:
A dehumidifying device capable of separating the supply gas into a dry gas having a reduced water vapor concentration and a wet gas having an increased water vapor concentration; a gas booster; and a gas-liquid separation device capable of removing condensate in the gas;
The supply gas obtained by mixing the raw material gas and the wet gas separated from the dehumidifier is boosted by the booster,
After removing moisture condensed by water vapor in the supply gas with a gas-liquid separator,
A dry gas production system configured to supply the supply gas to a dehumidifier.

2. A dry gas production method for obtaining a dry gas having a reduced water vapor concentration from a source gas containing moisture, comprising at least:
A dehumidifying device capable of separating the supply gas into a dry gas having a reduced water vapor concentration and a wet gas having an increased water vapor concentration; a gas booster; and a gas-liquid separation device capable of removing condensate in the gas;
After the water vapor in the supply gas mixed with the raw material gas and the wet gas pressurized by the pressure booster after being separated from the dehumidifier is removed by the gas-liquid separator,
A dry gas production system configured to supply the supply gas to a dehumidifier.

3. 3. The dry gas production system according to 1 or 2 above, wherein the dehumidifying device is a gas separation membrane.

4). 4. The dry gas production system according to any one of 1 to 3, wherein a gas heating device is provided between the gas-liquid separator and the dehumidifier.

5. 5. The dry gas production system according to any one of 1 to 4 above, wherein a part of the dry gas is supplied as a purge gas.

6). The dry gas production system according to any one of 1 to 4 above, wherein the second source gas dried from outside the system is supplied as a purge gas.

7). 7. The dry gas production system according to 5 or 6 above, wherein a dew point measuring means is provided on the high pressure dry gas line.

8). 7. The dry gas production system as described in 5 or 6 above, further comprising means for measuring the flow rate of the wet gas discharged from the dehumidifier.

9. The dry gas production system according to any one of claims 1 to 8, wherein a cooling device is provided upstream of the gas-liquid separator.

10. The dry gas production system according to any one of claims 1 to 9, wherein a water washing tower is provided in front of the gas-liquid separator.

11. The dry gas production system according to any one of claims 1 to 10, wherein the dehumidifying device is configured to depressurize a portion through which the wet gas flows to an atmospheric pressure or lower.

  According to the present invention, an economical and simple method for producing a high-pressure dry gas can be provided without substantially losing the raw material gas.

It is a figure which shows typically the structural example of the dry gas manufacturing method of 1st Embodiment. It is a figure which shows typically the example of a structure of the dry gas manufacturing method of 2nd Embodiment. It is a figure which shows typically the structural example of the dry gas manufacturing method of 3rd Embodiment. It is a figure which shows typically the structural example of the dry gas manufacturing method of 4th Embodiment. It is a figure which shows typically the structural example of the dry gas manufacturing method of 5th Embodiment. It is a figure which shows typically the structural example of the dry gas manufacturing method of 6th Embodiment. It is a figure which shows typically another structural example of the dry gas manufacturing method of 6th Embodiment. It is a figure which shows typically the structural example of the dry gas manufacturing method of 7th Embodiment. It is a figure which shows typically the structural example of the dry gas manufacturing method of 8th Embodiment. It is a figure which shows typically the structural example of the dry gas manufacturing method of 9th Embodiment. It is a figure which shows the basic composition of the dry gas manufacturing method by membrane separation, (a) shows the structure in connection with an Example, (b) has shown the structure in connection with a comparative example.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[First Embodiment]
The dehumidifying system of FIG. 1 includes a dehumidifying device 11, a booster 12, and a gas-liquid separator 13 that separate the supply gas 4 into a dry gas 4a and a wet gas 4b. The dehumidification system of FIG. 1 introduces the supply gas 4 mixed with the raw material gas 3 and the wet gas 4b from the dehumidifier 11 into the booster 12, pressurizes it, and then passes through the gas-liquid separator 13 It is configured to supply to the dehumidifier 11.

  The source gas 3 is not particularly limited as long as it is a gas under the conditions of atmospheric pressure and 25 ° C., but even a pure gas that does not contain impurities other than moisture such as hydrogen, helium, carbon dioxide, and nitrogen. Alternatively, it may be a mixed gas containing a plurality of gases other than moisture such as biogas, landfill gas, natural gas, combustion exhaust gas, reformed gas, and process exhaust gas.

  The booster 12 is not particularly limited as long as the pressure of the supply gas can be set to a predetermined pressure, and examples thereof include a compressor, a blower, and a fan.

  The pressure of the supply gas 4 is not particularly limited, but is set to a pressure suitable for operation in the dehumidifier 11. Usually, it is preferably from atmospheric pressure to 10 MPaG, more preferably from 0.3 MPaG to 3 MPaG. When the source gas 3 is less than the pressure preferable as the supply gas 4, the pressure is raised by the booster 12 as shown in FIG. 1.

  The gas-liquid separation device 13 may be any device as long as it can separate a gas and a liquid. For example, a demister, a coalescer filter, a centrifugal separation device, or the like can be used.

  The dehumidifier 11 may be any device as long as it can selectively remove moisture (water vapor) in the gas. For example, a separation membrane type dehumidifier, a PSA type dehumidifier, and a desiccant type dehumidifier Etc. are available.

  When the dehumidifying device 11 is a separation membrane type, for example, a separation membrane module using a hollow fiber membrane may be used. In this case, the separation membrane module may be either a so-called bore feed type or a shell feed type. The structure of the gas separation membrane module itself is conventionally known. For example, hundreds to hundreds of thousands of hollow fiber membrane bundles (hollow fiber bundles), a container for accommodating the hollow fiber membrane bundles, and both ends of the hollow fiber bundles You may provide the tube sheet etc. which were formed in the part. In the case of the bore feed type, the raw material gas is fed into the hollow membrane portion (primary side) from one opening of each hollow fiber membrane, and moisture in the raw material gas selectively permeates the membrane and passes through the membrane (secondary side). ).

  As the hollow fiber, one having a small thickness and a small diameter can be used. In this case, even a small apparatus can have a high membrane area and increase the separation efficiency. The hollow fiber is not limited, but may have a film thickness of 10 to 500 μm and an outer diameter of about 50 to 2000 μm. The gas separation membrane may be homogeneous, may be non-uniform such as a composite membrane or an asymmetric membrane, and may be microporous or nonporous. Examples of the gas separation membrane include those formed of polyimide, polyetherimide, polyamide, polyamideimide, polysulfone, polycarbonate, silicone resin, a polymer material such as a cellulose-based polymer, or a ceramic material such as zeolite. As a gas separation membrane formed of polyimide, for example, an aromatic polyimide hollow fiber separation membrane is preferable, and an aromatic polyimide asymmetric hollow fiber separation membrane is more preferable. Examples of the form of the hollow fiber bundle include a parallel arrangement, a crossing arrangement, and a woven form. Moreover, the hollow fiber bundle may be provided with a core tube at a substantially central portion, or a film may be wound around the outer peripheral portion of the hollow fiber bundle. Further, the hollow fiber bundle is not limited to a straight form, but may be a form bent in a U-shape.

  The operation of the dry gas production method of the present embodiment configured as described above will be described below.

  In this dry gas production method, first, the supply gas 4 composed of the raw material gas 3 containing water vapor and the wet gas 4b is boosted to a predetermined pressure by the booster 12. By raising the supply gas to a predetermined pressure, moisture in the supply gas is condensed. When the pressurized supply gas 4 passes through the gas-liquid separator 13, the condensed water is discharged out of the system as condensed water 9. The supply gas 4 from which condensed water has been removed by the gas-liquid separation device 13 is supplied to the dehumidifying device 11, and the dehumidifying device 11 is divided into a dry gas 4a from which moisture has been removed and a humidified humid gas 4b. . The dry gas 4a is used as a product gas, and the wet gas 4b is mixed with the raw material gas as described above.

In the case of a conventional dehumidification method (for example, a membrane separation method), a wet gas generated by permeation of a gas other than water vapor or purging a part of a dry gas to the wet gas side to improve dehumidification efficiency is Loss of supply gas occurred because it was exhausted outside.
According to the embodiment of the present invention, the generated wet gas is mixed with the raw material gas and returned to the system again, so that the gas can be dehumidified without causing loss of gas.

[Second Embodiment]
FIG. 2 is a diagram schematically illustrating the configuration of the second embodiment. In FIG. 2, the same reference numerals as those in FIG.

  The system in FIG. 2 includes a dehumidifying device 11, a booster device 12, and a gas-liquid separator 13 as in the above embodiment. When the pressure of the source gas 3 is equal to or higher than the pressure preferable as the supply gas 4, the wet gas 4 b is boosted by the booster 12, mixed with the source gas 3, and supplied to the gas-liquid separator 13. The raw material gas 3 may be mixed with the wet gas whose pressure has been increased as it is, or may be mixed with the wet gas whose pressure has been reduced after being reduced to a preferred pressure.

[Third Embodiment]
FIG. 3 is a diagram schematically illustrating the configuration of the third embodiment. In FIG. 3, the same reference numerals as those in FIGS. 1 and 2 are given to the structural portions having the same functions as those in the above embodiment.

  The system in FIG. 3 includes a dehumidifier 11, a booster 12, and a gas-liquid separator 13, and a heating device 14 is provided between the gas-liquid separator 13 and the dehumidifier 11, as in the above embodiment. Yes. As a result, the supply gas 4 can be prevented from being condensed by moisture being cooled between the gas-liquid separator 13 and the dehumidifier 11 by the outside air temperature or the like. The heating device 14 may be of any type as long as the temperature of the supply gas 4 can be raised.

[Fourth Embodiment]
FIG. 4 is a diagram schematically illustrating the configuration of the fourth embodiment. In FIG. 4, the same reference numerals as those in FIGS.

  The system of FIG. 4 includes a dehumidifying device 11, a booster device 12, and a gas-liquid separator 13 as in the above-described embodiment, and a line for supplying a part of the dry gas 4a to the dehumidifying device 11 as the purge gas 5a. Is provided. The purge gas 5a can be used to improve the dehumidifying efficiency of the dehumidifying device 11 as necessary. The flow rate adjusting means 15 is provided for adjusting the flow rate of the purge gas 5a, and may be of any type as long as the flow rate can be adjusted, and a flow rate adjusting valve, an orifice or the like is preferably used.

[Fifth Embodiment]
FIG. 5 is a diagram schematically illustrating the configuration of the fifth embodiment. In FIG. 5, the same reference numerals as those in FIGS.

  The system shown in FIG. 5 includes a dehumidifier 11, a booster 12, and a gas-liquid separator 13 as in the above embodiment, and further includes a line for supplying the gas 6 from outside the system to the dehumidifier 11 as a purge gas. Is provided. The gas 6 from outside the system is used to improve the dehumidifying efficiency by the dehumidifying device 11, and then mixed with the raw material gas 3 again as the wet gas 4b, and finally recovered as the dry gas 4a. The gas 6 from outside the system may be the same component as the raw material gas 3, or a different gas type from the raw material gas 3 may be used. When different gases are used, the dry gas 4a becomes a mixture of the raw material gas 3 and the gas 6 from outside the system, and an arbitrary dry mixed gas can be obtained.

[Sixth Embodiment]
FIG. 6 is a diagram schematically illustrating the configuration of the sixth embodiment. In FIG. 6, the same reference numerals as those in FIGS.

  The system of FIG. 6 includes a dehumidifying device 11, a pressure increasing device 12, and a gas-liquid separating device 13 as in the above embodiment, and further includes a dew point measuring means 16 and a flow rate adjusting means 17 for the dry gas 4a. By providing the dew point measuring means 16 and the flow rate adjusting means 17, it is possible to adjust the flow rate of the purge gas 5 a and efficiently operate the dehumidifier 11. Also, it is possible to follow changes in operating conditions such as changes in the flow rate and pressure of the supply gas 4 and changes in the required dew point of the dry gas 4a. As long as the flow rate can be adjusted, the flow rate adjusting unit 17 may be either a manual type or an automatic type, but is preferably one that can be automatically adjusted according to the measured value of the dew point measuring unit 16.

  FIG. 7 is a diagram schematically illustrating another configuration of the sixth embodiment. In FIG. 7, the same reference numerals as those in FIGS.

  The system of FIG. 7 includes a dehumidifying device 11, a booster device 12, and a gas-liquid separator 13 as in the above embodiment, and further, a dehumidifying device as a purge gas 6a for directly mixing the gas 6 from the outside with the dry gas. 11 can be branched to 6b that is supplied to 11. Similar to the sixth embodiment, by providing the dew point measuring means 16 and the flow rate adjusting means 17, it is possible to adjust the flow rate of 6 b and efficiently operate the dehumidifying device 11.

[Seventh Embodiment]
FIG. 8 is a diagram schematically illustrating the configuration of the seventh embodiment. In FIG. 8, the same reference numerals as those in FIGS.

  The system of FIG. 8 includes a dehumidifying device 11, a booster device 12, and a gas-liquid separator 13 as in the above embodiment, and further includes a flow rate measuring means 18 and a flow rate adjusting means 17 for the wet gas 4b. In the operation of the dehumidifier 11, such a form can be taken when the correlation between the dew point of the dry gas 4a and the flow rate of the wet gas 4b is clear.

[Eighth Embodiment]
FIG. 9 is a diagram schematically showing the configuration of the eighth embodiment. In FIG. 9, the same reference numerals as those in FIGS.

  The system shown in FIG. 9 includes a dehumidifying device 11, a booster device 12, and a gas-liquid separator 13, and a cooling device 19 is provided in front of the gas-liquid separator 13 as in the above embodiment. If it is such a form, since the condensation of the water | moisture content in gas will be accelerated | stimulated by cooling with the cooling device 19, it will become possible to reduce the load of the dehumidification apparatus 11. FIG.

[Ninth Embodiment]
FIG. 10 is a diagram schematically illustrating the configuration of the ninth embodiment. In FIG. 10, the same reference numerals as those in FIGS.

  The system shown in FIG. 10 includes a dehumidifying device 11, a booster device 12, and a gas-liquid separator 13, and a water washing tower 20 is provided in front of the gas-liquid separator 13 as in the above embodiment. If it is such a form, when gas passes through the washing tower 20, it becomes possible to exclude the gas soluble in water as the drainage 10 out of the system. Such a form is suitable when the source gas 3 contains a gas that is soluble in water and that is not desired to be mixed into the dry gas 4a.

[Tenth embodiment]
Although not shown, in the tenth embodiment, the efficiency of the dehumidifying device 11 can be improved by maintaining the wet gas side of the dehumidifying device 11 at atmospheric pressure or lower. The tenth embodiment can be combined with any of the above embodiments.

The result verified about the dry gas manufacturing system in this embodiment is demonstrated below.
In the verification, two separation membrane dryers (UM-C10) manufactured by Ube Industries, Ltd. were used as dehumidifiers. A nitrogen gas (F2) saturated at 40 ° C. was supplied to the dehumidifier at a pressure of 0.7 MPaG, and dry nitrogen gas (F3) having a pressure dew point of −20 ° C. was obtained at 0.7 MPaG.

(Examples and comparative examples)
Tables 1 and 2 below show the conditions and results of Examples and Comparative Examples.
FIG. 10A shows a form of the embodiment, wherein the wet gas (F4) discharged from the dehumidifier is mixed with the raw material gas (F1) and supplied to the dehumidifier again.
FIG. 10B shows a comparative example, and the wet gas (F5) discharged from the dehumidifier is directly discharged out of the system.

As shown in Table 1, the raw material of nitrogen amount required to obtain a dry nitrogen 12.8 nm ³ / h in the embodiment may be 12.8 ^Nm 3 / h. On the other hand, as shown in Table 2, in the comparative example, the amount of raw material nitrogen necessary to obtain 12.8 Nm ³ / h dry nitrogen is 16.0 Nm ³ / h in order to compensate for the amount discharged out of the system. Is required.

3 Gas containing moisture 4 Supply gas 4a Dry gas 4b Wet gas 5a Purge gas 6, 6a, 6b Gas from outside 9 Condensed water 10 Drain 11 Dehumidifier 12 Booster 13 Gas-liquid separator 14 Heater 15, 17 Flow rate Adjustment means 16 Dew point measurement means 17 Flow rate adjustment valve 18 Flow rate measurement means 19 Cooling device 20 Flush tower

Claims (11)

A dry gas production method for obtaining a dry gas having a reduced water vapor concentration from a source gas containing moisture, comprising at least:
A dehumidifying device capable of separating the supply gas into a dry gas having a reduced water vapor concentration and a wet gas having an increased water vapor concentration; a gas booster; and a gas-liquid separation device capable of removing condensate in the gas;
The supply gas obtained by mixing the raw material gas and the wet gas separated from the dehumidifier is boosted by the booster,
After removing moisture condensed by water vapor in the supply gas with a gas-liquid separator,
A dry gas production system configured to supply the supply gas to a dehumidifier. A dry gas production method for obtaining a dry gas having a reduced water vapor concentration from a source gas containing moisture, comprising at least:
A dehumidifying device capable of separating the supply gas into a dry gas having a reduced water vapor concentration and a wet gas having an increased water vapor concentration; a gas booster; and a gas-liquid separation device capable of removing condensate in the gas;
After the water vapor in the supply gas mixed with the raw material gas and the wet gas pressurized by the pressure booster after being separated from the dehumidifier is removed by the gas-liquid separator,
A dry gas production system configured to supply the supply gas to a dehumidifier. The dry gas production system according to claim 1 or 2, wherein the dehumidifying device is a gas separation membrane.
The dry gas production system according to any one of claims 1 to 3, wherein a gas heating device is provided between the gas-liquid separator and the dehumidifier.
The dry gas production system according to claim 1, wherein a part of the dry gas is supplied as a purge gas.
The dry gas production system according to any one of claims 1 to 4, wherein the second source gas dried from outside the system is supplied as a purge gas.
7. The dry gas production system according to claim 5, wherein a dew point measuring means is provided on the high pressure dry gas line.
7. The dry gas production system according to claim 5, further comprising means for measuring a flow rate of the wet gas discharged from the dehumidifier.
The dry gas production system according to any one of claims 1 to 8, wherein a cooling device is provided upstream of the gas-liquid separator.
The dry gas production system according to any one of claims 1 to 9, wherein a water washing tower is provided in front of the gas-liquid separator.
  The dry gas production system according to any one of claims 1 to 10, wherein the dehumidifying device is configured to depressurize a portion through which the wet gas flows to an atmospheric pressure or lower.

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