JP2007091570A - Method and device for reducing gaseous oxygen remaining in gaseous nitrogen with high concentration produced from air - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problems regarding a gaseous oxygen sensor, e.g., that, when its concentration is made low, reaction velocity is extremely slow, and, when combustible gas is included therein, trouble may occur, also, since the concentration of gaseous hydrogen is not controlled, there is a need of specially providing a gaseous hydrogen warning device, and, further, in the case of the device where gaseous oxygen and gaseous hydrogen are reacted, heat resistance and high temperature properties are required. <P>SOLUTION: Gaseous nitrogen 102 with a high concentration including gaseous oxygen as impurities produced from the air and gaseous hydrogen 101 are mixed and reacted, so as to produce water, thus the gaseous oxygen is reduced, and, the concentration in a trace amount of gaseous hydrogen included in gaseous nitrogen 104 with a high concentration after the reaction is measured, and, by utilizing the result, the concentration of gaseous oxygen is made controllable. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method and apparatus for reducing oxygen gas remaining in high-concentration nitrogen gas produced from air. More specifically, the present invention relates to a high-concentration nitrogen gas and hydrogen gas mixed together to react with water. By using a hydrogen gas sensor that has a quick reaction instead of an oxygen gas sensor, the measurement result can be obtained immediately and more efficiently and efficiently than air. The technique for reducing the oxygen gas remaining in the high concentration nitrogen gas is described.

  Conventionally, as a technique related to a method and apparatus for reducing oxygen gas remaining in high-concentration nitrogen gas produced from air, the concentration of oxygen gas has been measured by an oxygen gas sensor.

  In this case, a galvanic sensor and a zirconia sensor were used as oxygen gas sensors for measuring low concentrations (nitrogen gas concentration of 99.999% or more and residual oxygen gas concentration of 10 ppm or less).

  However, the conventional method and apparatus for reducing oxygen gas remaining in high-concentration nitrogen gas produced from air have the following problems.

  That is, in the case of a galvanic sensor, which is a kind of oxygen gas sensor, the reaction rate becomes extremely slow when the concentration is low, and it takes a long time (3-5 hours) to show an accurate value, and the fluctuation is a long cycle equipment. Although it can be used in systems and systems, it cannot be used in facilities and systems that are activated in a short time (5 to 10 minutes).

  On the other hand, in the case of a zirconia-type sensor, which is a kind of oxygen gas sensor, combustion occurs when combustible gas (hydrogen, carbon-based substances, etc.) is contained, and the displayed concentration becomes “0”. Since it is not shown, it could not be used in a hydrogen gas addition type device that reduces oxygen gas by controlling the amount of hydrogen gas added, and that reduces oxygen gas remaining in high concentration nitrogen gas.

  In addition, in the system that feeds back the amount of unreacted oxygen gas by the oxygen gas sensor, the hydrogen gas concentration is not controlled, so how much hydrogen gas explosively burns when the hydrogen gas concentration in the atmosphere reaches 4%. It was unknown whether it occurred, and a separate hydrogen gas alarm device was necessary.

  Furthermore, the reaction to produce water from oxygen gas and hydrogen gas is an exothermic reaction, and when the amount of oxygen gas remaining in the nitrogen gas is large, the temperature becomes high after the reaction, and the oxygen gas sensor that measures the concentration of oxygen gas is Heat resistance and high temperature characteristics were required.

  The present invention is a method for reducing oxygen gas remaining in high-concentration nitrogen gas produced from air, and reducing oxygen gas by mixing high-concentration nitrogen gas 102 and hydrogen gas 101 to produce water. And measuring the concentration of the minute hydrogen gas contained in the high-concentration nitrogen gas 104 after the reaction, and using the result, the concentration of the oxygen gas can be adjusted. As a result of measuring the concentration of hydrogen gas, the hydrogen gas 101 is reduced when the minute hydrogen gas is “+”, and the hydrogen gas when the minute hydrogen gas is “0”. 101 is controlled so as to increase the amount, and further, the result of measuring the concentration of the minute hydrogen gas with respect to the flow rate of one hydrogen gas 101 and the flow rate with respect to another hydrogen gas 101 are measured. Estimating the flow rate of the hydrogen gas 101 at which the minute hydrogen gas is 0% from the two results of measuring the concentration of a small amount of hydrogen gas, and controlling the flow rate of the hydrogen gas 101 based on the estimated result By solving the above-mentioned problems, the above problems have been solved.

  Further, the present invention is an apparatus for reducing oxygen gas remaining in high-concentration nitrogen gas produced from air, in which oxygen gas is produced by mixing and reacting high-concentration nitrogen gas 102 and hydrogen gas 101 to produce water. , A hydrogen gas sensor 62 that is located downstream of the reaction tank 31 to measure the concentration of minute hydrogen gas, and the flow rate of the hydrogen gas 101 is controlled by the measurement result of the hydrogen gas sensor 62. And a mass flow 15 for changing the flow rate of the hydrogen gas 101 according to information from the controller 63, so that the concentration of oxygen gas can be adjusted. According to the measurement result of the sensor 62, when the minute hydrogen gas is “+”, the hydrogen gas 101 is reduced. When the amount of hydrogen gas is “0”, the amount of the hydrogen gas 101 is increased, and further, a throttle valve 32 is provided to increase the pressure of the reaction tank 31. By doing so, the above-mentioned problems have been solved.

  As is clear from the above description, the present invention can provide the following effects.

  First, oxygen gas is reduced by mixing and reacting nitrogen gas with high concentration produced from air and hydrogen to make water, and the minute hydrogen gas contained in nitrogen gas with high concentration after reaction is reduced. By measuring the concentration and making it possible to adjust the concentration of oxygen gas using the result, an apparatus with a short reaction time of 3 to 5 seconds, a stable accuracy, and a stable high temperature became possible.

  Second, based on the result of measuring the concentration of minute hydrogen gas, the hydrogen gas is reduced when the minute hydrogen gas is “+”, and the hydrogen gas when the minute hydrogen gas is “0”. By controlling to increase the amount of oxygen, it has become possible to control oxygen gas with a hydrogen gas sensor that has advantages in various respects.

  Thirdly, by providing a throttle valve in order to increase the pressure in the reaction vessel, the reaction can be promoted as necessary.

  Fourth, from the result of measuring the concentration of a minute hydrogen gas with respect to the flow rate of one hydrogen gas and the result of measuring the concentration of a minute hydrogen gas with respect to the flow rate of another hydrogen gas, By presuming the flow rate of hydrogen gas at which 0% becomes 0% and controlling the flow rate of hydrogen gas based on the estimated result, it becomes possible to make the amount of oxygen gas remaining as close as possible to 0%.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
Here, FIG. 1 is a diagram showing the whole of the present invention.

  As can be seen in FIG. 1, reference numeral 121 denotes a nitrogen gas pipe which allows a high-concentration nitrogen gas 102 to flow. In this case, although not specifically illustrated, an apparatus for producing high-concentration nitrogen gas from air such as a separation membrane system, a PSA system, or liquid air is connected upstream of the nitrogen gas pipe 121. . Therefore, most of the nitrogen gas 102 having a high concentration is mixed with oxygen gas as an impurity. The nitrogen gas pipe 121 is connected to the merging part 92 via the branch part 93 and the nitrogen gas pipe 122, and the pressure gauge 21 for measuring the pressure of the nitrogen gas 102 having a high concentration is connected to the branch part 93. Yes.

  On the other hand, an apparatus for producing the hydrogen gas 101 and a hydrogen gas cylinder are connected to the upstream side of the hydrogen gas pipe 111 through an on-off valve 11 that is manually opened and closed. Further, downstream of the hydrogen gas pipe 111, a branch part 91 connecting a filter 12 for removing foreign substances, a hydrogen gas pipe 112, and a pressure switch 13 that emits some information when a certain pressure is sensed, A hydrogen gas pipe 113, a solenoid valve 14 that opens and closes according to information from the pressure switch 13, a hydrogen gas pipe 114, a mass flow 15 that adjusts the flow rate of the passing hydrogen gas 101, a hydrogen gas pipe 115, and from upstream The hydrogen gas 101 flows downstream, but is connected to the junction 92 through the check valve 16 that shuts off the flow from the downstream to the upstream and the hydrogen gas pipe 116.

  Next, the junction 92 is connected to the reaction tank 31 via a mixed gas pipe 131 centered on nitrogen gas. In this case, the reaction tank 31 is filled with a catalyst, and when the mixed gas passes, reaction heat is generated while performing the reaction shown in the following formula 1.

Number 1

O ₂ + 2H ₂ → 2H ₂ O + reaction heat

  As an example of the catalyst to be used, a catalyst in which Pd in angstrom units is attached to the surface of a cylindrical alumina having a size of 3.2 mmΦ × 3.2 mmH. However, regarding the size, an example of actual use is shown, and the present invention is not limited to this. Further, the shape is not limited to the cylinder, and may be a sphere. Therefore, the nitrogen gas 103, 104 having a high concentration after the reaction at a high temperature flows downstream of the reaction tank 31.

  Further, downstream of the reaction tank 31, a post-reaction nitrogen gas pipe 132, a throttle valve 32, a post-reaction nitrogen gas pipe 133, a filter 33 for removing foreign matter, and a post-reaction nitrogen gas pipe 134 are passed. And connected to the branching portion 94.

Here, the reason why the throttle valve 32 is positioned is that the catalyst filled in the reaction tank 31 does not react unless there is a back pressure (at least 0.7 kgf / cm ² or more is required). By restricting the flow path with the throttle valve 32, the pressure in the reaction tank 31 is increased to promote the reaction.

  On the other hand, the branch part 94 branches to a nitrogen gas pipe 141 after the reaction and a nitrogen gas branch pipe 151 after the reaction. The post-reaction nitrogen gas pipe 141 has a post-reaction concentration via a check valve 41 and a post-reaction nitrogen gas pipe 142 that flow nitrogen gas from upstream to downstream but shut off from downstream to upstream. The high nitrogen gas 103 can be sent out.

  By the way, the nitrogen gas branch pipe 151 after the reaction is further branched into a measurement pipe 161 and a nitrogen gas branch pipe 152 after the reaction at the branch portion 95, and the nitrogen gas branch pipe 152 after the reaction is opened and closed manually. The nitrogen gas 104 having a high concentration after reaction can be sent out through the valve 51 and the nitrogen gas branch pipe 153 after reaction.

  The measurement pipe 161 is connected to the hydrogen gas sensor 62 via a throttle valve 61 that changes the flow rate of the flowing fluid and a measurement pipe 162. In this case, the hydrogen gas sensor 62 uses a Pd / Ni film sensor or a semiconductor gas sensor that has a reaction time as short as 3 to 5 seconds. It is possible to measure the concentration.

  The data measured by the hydrogen gas sensor 62 is sent to the controller 63 as a signal 163. When the concentration of the minute hydrogen gas is “+”, the minute hydrogen gas is “0” so that the hydrogen gas 101 is reduced. In the case of "", the hydrogen gas 101 can be sent to the mass flow 15 in the form of a signal 164 from the controller 63 so as to increase the amount.

  The method and apparatus for reducing oxygen gas remaining in high-concentration nitrogen gas produced from air according to the present invention is configured as described above, and its operation will be described below.

  First, the high concentration nitrogen gas 102 from one side is passed through the nitrogen gas pipe 121, the branch part 93, and the nitrogen gas pipe 122, and the hydrogen gas 101 from the other side is connected to the on-off valve 11, the hydrogen gas pipe 111, and the filter 12. The hydrogen gas pipe 112, the branch part 91, the hydrogen gas pipe 113, the solenoid valve 14, the hydrogen gas pipe 114, the mass flow 15, the hydrogen gas pipe 115, the check valve 16, and the hydrogen gas pipe 116 are connected to each other at the junction 92. Have joined. In this case, the nitrogen gas concentration of the high-concentration nitrogen gas 102 is about 99.5 to 99.99%. In addition, the pressure switch 13 is connected to the branch part 91, and the electromagnetic valve 14 is opened and closed by the information of the pressure switch 13.

  Therefore, the merged mixed gas is sent from the merge portion 92 to the reaction tank 31 via the mixed gas pipe 131 centered on nitrogen gas. In the reaction tank 31, water is produced by reacting a minute amount of oxygen gas contained in the high concentration nitrogen gas 102 with the hydrogen gas 101, and at the same time, a minute amount of oxygen gas is further generated while generating heat. It is decreasing. Therefore, depending on the amount of hydrogen gas 101 supplied, hydrogen gas or oxygen gas may remain.

  On the other hand, the gas after reaction is the nitrogen gas pipe 132 after reaction, the throttle valve 32, the nitrogen gas pipe 133 after reaction, the filter 33, the nitrogen gas pipe 134 after reaction, the branch part 94, and the nitrogen gas pipe 141 after reaction. The high concentration nitrogen gas 103 after the reaction is sent out through the check valve 41 and the nitrogen gas pipe 142 after the reaction. Therefore, if the throttle valve 32 is throttled as necessary, the pressure in the reaction tank 31 increases and the reaction is promoted.

  Here, from the branch portion 94, the post-reaction nitrogen gas branch pipe 151, the branch portion 95, the post-reaction nitrogen gas branch pipe 152, the on-off valve 51, and the post-reaction nitrogen gas branch pipe 153 are passed through after the reaction. Nitrogen gas 104 having a high concentration is sent out. In this case, the high-concentration nitrogen gas 103 after the reaction and the high-concentration nitrogen gas 104 are only branched and may be considered to be the same component and the concentration.

  From the branching portion 95, the gas having the same concentration as the high concentration nitrogen gas 104 is sent to the hydrogen gas sensor 62 through the measurement pipe 161, the throttle valve 61, and the measurement pipe 162, and is supplied to the hydrogen gas sensor 62. The concentration of is to be measured. As a matter of course, it is possible that a high-temperature fluid flows as the fluid flowing here, but it can be said that the hydrogen gas sensor 62 is stable in terms of high-temperature characteristics.

  In this case, the result measured by the hydrogen gas sensor 62 is sent to the controller 63 as a signal 163, and the controller 63 makes a certain determination, and the result is sent to the mass flow 15 as a signal 164. The mass flow 15 adjusts the flow rate according to the instruction. It is operating.

  That is, the data measured by the hydrogen gas sensor 62 is sent to the controller 63 as a signal 163. When the concentration of the minute hydrogen gas is “+”, the minute hydrogen gas is “0” so that the hydrogen gas 101 is reduced. In the case of "," the hydrogen gas 101 is sent to the mass flow 15 in the form of a signal 164 from the controller 63 so as to increase the amount. Therefore, by controlling in this way, the concentration of nitrogen gas can be increased to 99.999% or more.

  Further, as another means for determining the flow rate of the hydrogen gas 101, the result of measuring the concentration of a minute hydrogen gas with respect to the flow rate of one hydrogen gas 101 and the concentration of the minute hydrogen gas with respect to the flow rate of another hydrogen gas 101. From the two results of the measurement, the flow rate of the hydrogen gas 101 at which the minute hydrogen gas becomes 0% is estimated under the assumption that the two results are approximately on a straight line. It can be considered that the flow rate of the hydrogen gas 101 is controlled according to the result.

  By using a hydrogen gas sensor instead of an oxygen gas sensor, a reaction can be confirmed in a short time, and a device that reduces oxygen gas remaining in high-concentration nitrogen gas created from stable and accurate air has become possible. .

  Diagram showing the entire invention of the present application

Explanation of symbols

11 .... On-off valve 12 .... Filter 13 .... Pressure switch 14 .... Solenoid valve 15 .... Mass flow 16 .... Check valve 21 ... Pressure gauge 31 ... Reaction tank 32 ... Throttle valve 33 ... Filter 41 ... Check valve 51 ... ...... Open / close valve 61 ... Throttle valve 62 ... Hydrogen gas sensor 63 ... Controller 91 ... Branch 92 ... Junction part 93 ... Branch part 94 ... Branch part 95 ... Branch part 101 ... Hydrogen gas 102 ... High concentration nitrogen gas 103 ... .... High concentration nitrogen gas after reaction 104 ... High concentration nitrogen gas after reaction 111 ... Hydrogen gas Pipe 112 ... Hydrogen gas pipe 113 ... Hydrogen gas pipe 114 ... Hydrogen gas pipe 115 ... Hydrogen gas pipe 116 ... Hydrogen gas pipe 121 ... ..Nitrogen gas piping 122... Nitrogen gas piping 131... Mixed gas piping centering on nitrogen gas 132... Nitrogen gas piping 133 after reaction 133. Nitrogen gas piping 134... Nitrogen gas piping after reaction 141... Nitrogen gas piping after reaction 142... Nitrogen gas piping after reaction 151. Branch pipe 152... Nitrogen gas branch pipe after reaction 153... Nitrogen gas branch pipe after reaction 161... Measurement pipe 162... Measurement pipe 163. ..Signal 164 ... Signal

Claims (6)

  In the method of reducing oxygen gas remaining in high-concentration nitrogen gas created from air, oxygen gas is reduced by mixing and reacting high-concentration nitrogen gas (102) and hydrogen gas (101). Produced from air characterized in that the concentration of minute hydrogen gas contained in the highly concentrated nitrogen gas (104) after the reaction was measured and the oxygen gas concentration could be adjusted using the result. To reduce oxygen gas remaining in high concentration nitrogen gas.   As a result of measuring the concentration of the minute hydrogen gas, when the minute hydrogen gas is “+”, the amount of the hydrogen gas (101) is reduced when the minute hydrogen gas is “+”. 2. The method of reducing oxygen gas remaining in nitrogen gas having a high concentration produced from air according to claim 1, wherein control is performed so as to increase the amount of the hydrogen gas (101).   Two results, the result of measuring the concentration of the minute hydrogen gas with respect to the flow rate of one hydrogen gas (101) and the result of measuring the concentration of the minute hydrogen gas with respect to the flow rate of another hydrogen gas (101) The flow rate of the hydrogen gas (101) at which the minute hydrogen gas becomes 0% is estimated, and the flow rate of the hydrogen gas (101) is controlled according to the estimated result. A method of reducing oxygen gas remaining in high-concentration nitrogen gas produced from air.   In the device that reduces oxygen gas remaining in high-concentration nitrogen gas created from air, oxygen gas is reduced by mixing and reacting high-concentration nitrogen gas (102) and hydrogen gas (101). A hydrogen gas sensor (62) that is located downstream of the reaction tank (31) to measure the concentration of minute hydrogen gas, and the hydrogen gas sensor (62) is used to measure the hydrogen. By providing a controller (63) for controlling the flow rate of the gas (101) and a mass flow (15) for changing the flow rate of the hydrogen gas (101) according to information from the controller (63), the concentration of oxygen gas A device for reducing oxygen gas remaining in high-concentration nitrogen gas produced from air, which is characterized by being adjustable.   According to the measurement result of the hydrogen gas sensor (62), when the minute hydrogen gas is “0”, the amount of the hydrogen gas (101) is reduced when the minute hydrogen gas is “+”. 5. The apparatus for reducing oxygen gas remaining in high-concentration nitrogen gas produced from air according to claim 4, wherein the hydrogen gas (101) is increased.   The oxygen gas remaining in the high-concentration nitrogen gas produced from air according to claim 4 or 5, wherein a throttle valve (32) is provided to increase the pressure in the reaction vessel (31). Reducing device.

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