JPS624439A - Apparatus for producing atmospheric gas - Google Patents

Abstract

PURPOSE:To obtain a gas consisting essentially of N2 and having stabilized contents of CO and O2 at low temp. by providing a catalytic reactor for passing a catalytic combustion waste gas and reducing the oxygen in the gas on the downstream side of an oxygen partial pressure detector. CONSTITUTION:Zirconia is used as the detecting cell in an oxygen partial pressure detector 6. A gas to be measured is introduced into the detected by utilizing the pressure difference between an inlet pipeline 6a and an outlet pipeline 6b and the oxygen partial pressure is detected by the detecting cell. The value of the detected oxygen partial pressure is fed to a regulator 7, a flow control valve 8 is controlled on the basis of the value so that the theoretical air fuel ratio can be obtained in the combustion in the first catalyst reactor 1 and the supply of hydrocarbonic fuel 9 is controlled. A waste gas 10 contg. oxygen is supplied from the upstream side of the first catalytic reactor 1 and mixed with the hydrocarbonic fuel 9. The gaseous mixture is passed through the catalytic reactor 1, a pipeline and a catalytic reactor 2.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to an apparatus for producing atmospheric gas mainly composed of N2 from combustion exhaust gas using a contact combustor. CO using a catalytic combustion reactor
The present invention relates to an atmospheric gas production device with little variation in temperature and 0281 degrees.

(Prior Art) Conventionally, as shown in FIG. 5, as an apparatus for efficiently producing atmospheric gas, particularly nitrogen gas, using exhaust gas, a mixed gas of combustion exhaust gas 51 and hydrocarbon fuel 52 is mixed into pd and pd.
In an apparatus for catalytically burning oxygen in exhaust gas with a hydrocarbon fuel 52 in a catalytic reactor 53 supporting an oxidation catalyst such as t and producing an atmospheric gas 54 mainly composed of N2, A device for supplying hydrocarbon fuel 52 through feedback control using a regulator 56 and a temperature control valve 57 according to the partial pressure of oxygen in the atmospheric gas 54 detected by an oxygen partial pressure detector 55 is disclosed in Japanese Patent Application Laid-open No. 60
It is known from the publication No.-60489.

(Problems to be Solved by the Invention) However, in the above-mentioned apparatus, a detector using a solid electrolyte such as zirconia is mainly used as an oxygen partial pressure detector. As shown in the output of the pressure detector, the output changes rapidly near the equivalence point of the stoichiometric air ratio, making it difficult to control near the equivalence point.
As shown in the figure, the concentration changes of CO and 02 are large, and there is a drawback that it is not possible to obtain a stable gas with a low concentration of CO and 021 degrees. Furthermore, even when a magnetic type oxygen partial pressure detector is used as the lvi elemental partial pressure detector, there is a drawback that the response time is slow due to its principle, resulting in large fluctuations.

The purpose of the present invention is to eliminate the above-mentioned problems and reduce CO, which is a reducing gas, and 02, which is an oxidizing gas, thereby creating an atmospheric gas mainly composed of N2 with a low and stable concentration of CO and 02. The present invention aims to provide an atmospheric gas production device that can obtain the following.

(Means for Solving the Problems) The atmospheric gas production device of the present invention includes a first catalytic reactor that catalytically burns a mixed gas of a combustion exhaust gas containing oxygen and a hydrocarbon fuel; an M elemental partial pressure detector that detects the oxygen partial pressure in the catalytic combustion exhaust gas discharged from the reactor;
a fuel regulator that controls the amount of hydrocarbon fuel to be added to the combustion exhaust gas introduced into the upstream portion of the first catalytic reactor according to the oxygen partial pressure detected by the oxygen partial pressure detector; a second catalyst for further reducing oxygen in the gas by flowing the catalytic combustion exhaust gas discharged from the first catalytic reactor downstream of the oxygen partial pressure detector; It is characterized by being equipped with a reactor.

(Function) With the above-described configuration, in addition to feedback control using the oxygen partial pressure detector, trace amounts of CO and 02 discharged from the first catalytic reactor are further catalytically combusted in the second catalytic reactor. Therefore, it is possible to easily obtain an atmospheric gas containing N2 as a main component with low 02 and CO2 degrees.

(Embodiment) FIG. 1 is a diagram showing an embodiment of the atmospheric gas production apparatus of the present invention. In this embodiment, the second catalytic reactor 2 is connected in series on the downstream side of the first catalytic reactor 1 to form the entire catalytic reactor. Inside each catalytic reactor 1.2,
Preferably palladium on the ceramic honeycomb catalyst carrier,
Catalysts 3 and 4 carrying an oxidation catalyst such as platinum are stacked in multiple stages. Oxygen partial pressure detection i'! ! 46 inlet pipes 6a
and the outlet pipe line 6b. This oxygen partial pressure detector 6 uses zirconia as a detection cell, and has an inlet pipe 6a.
The gas to be measured is introduced into the detector by utilizing the pressure difference between the output pipe 6b and the outlet pipe 6b, and the oxygen partial pressure is detected by the detection cell. The detected oxygen partial pressure value is supplied to the regulator 7,
Based on this value, the amount of hydrocarbon fuel 9 supplied is controlled by adjusting the flow control valve 8 so that the combustion in the -C first catalytic reactor 1 reaches the stoichiometric air ratio. - In the above-mentioned apparatus, after supplying the exhaust gas 10 containing oxygen from the upstream side of the first catalytic reactor 1 and mixing it with the hydrocarbon fuel 9, the mixed gas is transferred to the first catalytic reactor 1. When passed through the pipe line 5 and the second catalytic reactor 2, the mixed gas undergoes catalytic combustion in each catalytic reactor and flows out as a desired atmospheric gas 11 to the downstream side of the second catalytic reactor 2.

FIG. 2 is a diagram showing another embodiment of the atmospheric gas production apparatus of the present invention. In FIG. 2, the same members as in FIG. 1 are given the same reference numerals, and their explanations will be omitted. The difference from the embodiment shown in FIG. to bypass conduit 13 via valve 12.
The point is that The only way to do this is to burn and remove the 00 minutes in the exhaust gas 10, so the first catalytic reactor 1
In order to further reduce the amount of 00 min in the gas that exits, the exhaust gas 10 containing oxygen is supplied to the second catalytic reactor 2 in a small bypass manner, and the 00 min is further combusted in the second catalytic reactor 2. This is to make it happen.

Figure 3 shows an N2 system incorporating the atmospheric gas production device of the present invention.
FIG. 1 is a diagram showing an example of a gas production device. The exhaust gas 10 containing N2 as a main component and about 4% oxygen is contained in a gas cylinder 21.
After about 0.8% of propane gas (C3H8) is mixed with the mixture, it is catalytically burned in the first catalytic reactor 1 and the second catalytic reactor 2 to produce about 10 ppHl of 02, about 11% of C○.
An atmospheric gas 11 containing approximately 00 pp of N2 as a main component is obtained. Since the atmospheric gas 11 after the reaction has a high temperature of about 700 m, it is supplied to the resurge tank 23 where it is cooled through a water-cooled cooler 22. The atmospheric gas 11 supplied to the surge tank 23 stays there for about 1 minute to make the temperature uniform. After that, the atmospheric gas 11 is passed through the U-olide adsorption tower 24 to remove moisture and carbon dioxide from the atmospheric gas 11. A desired N2 gas containing approximately 99.89% N2 can be obtained.

Example 1 An atmospheric gas with a low oxygen concentration was produced from combustion exhaust gas containing oxygen using the apparatus shown in FIG. The introduced combustion exhaust gas was propane gas with an average oxygen concentration of 4 vol%, an oxygen concentration variation range of 3.5 to 4.5 volts, and an o 1%, and was flowed at a rate of 1 ONm3 per hour. The first catalytic reactor 1 has a honeycomb shape with a pitch of -1.7 mm, a diameter of 8 Omm, a height of 50 mm, and a supported amount of 2Q.
/12. The palladium catalyst was packed in four stages. In addition, the second catalytic reactor 2 was filled with two stages of platinum catalysts having a honeycomb shape with a pitch of 1.7 mm, a diameter of 80 m+a, a height of 50 mm, and a supported m2g/f2. A zirconia type oxygen detector is used as the oxygen partial pressure detector 6, and propane gas is supplied to the upstream side of the first catalytic reactor 1 via a flow control valve 8 so that the output voltage of this detector is 690 mV. Injected.

Further, as a comparative example, the apparatus shown in FIG. 5 was used, and four stages of palladium catalysts and two stages of platinum catalyst were installed in the catalytic reactor 53, and the output voltage of the oxygen partial pressure detector 55 was 69.
The propane inflow rate was controlled to be 0 mV.

Table 1 shows the co concentration and 02 concentration in the atmospheric gas obtained as a result, and FIG. 4 shows the variation of these values over time.

Table 1 From Table 1, the examples of the present invention have lower 02,
It can be seen that the CO concentration can be achieved and the range of concentration fluctuation can be reduced.

Example 2 An atmospheric gas with a low oxygen concentration was produced from combustion exhaust gas containing oxygen under the same conditions as in Example 1 using an apparatus having a bypass conduit 13 as shown in FIG. At this time, the valve 12 was adjusted to supply exhaust gas to the second catalytic reactor 2 through the bypass conduit 13 at a rate of 0.2β/min. COf in the resulting gas! degrees and 02m degrees are not shown in Table 2. In addition, as a comparative example, a test similar to Example 1 was conducted.

Table 2 It can be seen from Table 2 that in this example, a lower 02° and especially lower CO concentration can be achieved than in the comparative example.

The present invention is not limited to the above-mentioned actual examples, but can be modified and changed in many ways. For example, in the above embodiment, four stages of catalyst were used in the first catalytic reactor and two stages of catalyst were used in the second catalytic reactor, but the number of stages may be any number and can be selected as needed. Any type of catalyst can be used as long as it is an oxidation catalyst. Furthermore, it is also possible to use a plurality of catalytic reactors as the second catalytic reactor.

(Effects of the Invention) As is clear from the detailed explanation above, according to the atmospheric gas production device of the present invention, the exhaust gas discharged from the first catalytic reactor is further catalytically combusted in the second catalytic reactor. N2 with lower 02 and CO concentration than combustion exhaust gas.
An atmospheric gas containing as a main component can be obtained easily and inexpensively. Furthermore, the range of concentration fluctuation of the iqed gas can be reduced.

[Brief explanation of drawings]

1 and 2 are diagrams each showing an embodiment of the atmospheric gas production device of the present invention, and FIG. 3 is an N2 diagram incorporating the atmospheric gas production device of the present invention.
A line diagram showing an example of a gas production head; FIG. 4 is a graph showing changes in J3 RI 02 and CO depth over time in the apparatus of the present invention; and FIG. 5 is a graph showing one example of a conventional atmospheric gas production apparatus. FIG. 6 is a graph showing the output of a zirconia oxygen partial pressure detector, and FIG. 7 is a graph showing changes in O2 and CO intensity over time in a conventional device. 1... First catalytic reactor 2... Second catalytic reactor 3.4... Catalyst 5... Pipe line 6... Oxygen partial pressure detector 6a... Inlet pipe line 6b ...Outlet pipe
7...Adjuster 8...Flow rate adjustment valve 9...
Hydrocarbon fuel 10...exhaust gas, 11...
Atmospheric gas 12...Valve 13...Bypass conduit 21...Gas cylinder 22...Water-cooled cooler 23...Surge tank 24...Zeolyte 1 to adsorption tower Fig. Figure 2 - IOP pup is running Figure 4 Time 54g

Claims (1)

[Claims] 1. A first catalytic reactor for catalytically combusting a mixed gas of a combustion exhaust gas containing oxygen and a hydrocarbon fuel; an oxygen partial pressure detector that detects an oxygen partial pressure; and a hydrocarbon to be added to the combustion exhaust gas introduced into the upstream portion of the first catalytic reactor according to the oxygen partial pressure detected by the oxygen partial pressure detector. In an atmospheric gas production device comprising a fuel regulator that controls the amount of fuel in the system, the catalytic combustion exhaust gas discharged from the first catalytic reactor is passed downstream of the oxygen partial pressure detector to generate a gas atmosphere. 1. An atmospheric gas production device comprising a second catalytic reactor for further reducing oxygen. 2. A bypass conduit is connected between the upstream part of the first catalytic reactor and the upstream part of the second catalytic reactor that is downstream of the oxygen partial pressure detector, and the oxygen-containing combustion is performed. The atmospheric gas production device according to claim 1, which bypasses and supplies a part of the exhaust gas. 3. The atmospheric gas production apparatus according to claim 1 or 2, wherein the first and second catalytic reactors each have an oxidation catalyst supported on a ceramic honeycomb catalyst carrier. 4. The atmospheric gas production apparatus according to claim 3, wherein the oxidation catalyst in the first catalytic reactor is Pd, and the oxidation catalyst in the second catalytic reactor is Pt.