JP3388103B2 - Exhaust gas measurement method and device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for measuring exhaust gas, and more particularly, it is highly reliable and accurate, and can easily and quickly produce sulfur dioxide (SO ₂ ) and socks (SO _x ) in exhaust gas. And an exhaust gas measuring device that can be used to carry out the method and is easy to maintain.

[0002]

2. Description of the Related Art Conventionally, SO ₂ and SO in exhaust gas
_x [mainly SO ₃ , SO ₄ (SO ₄ ^2- ), and other S ₂ O, S
For measuring [O], for example, the exhaust gas measuring device shown in FIG. 5 has been used. Hereinafter, the amount of SO ₂ and S in the sample (for example, automobile exhaust gas) and S using the apparatus of FIG.
A method for measuring the amount of O _x will be described. The sample 1 containing SO ₂ and SO _x is introduced to the SO _x converter 3 or the SO _x adsorber 4 by switching the exhaust gas flow path by the flow path switch 2. If the object 1 is guided to the SO _x converter 3, SO _x in SO _x converter 3 is converted to SO ₂ (SO ₂ is not changed), then after passing through the pump 5, analyzer 6 The total amount of SO ₂ is measured at. Sample 1 is SO
When introduced to the _x adsorber 4, SO in SO _x adsorber 4
_{After x} is adsorbed and removed and then passed through the pump 5, the total amount of SO ₂ is measured by the analyzer 6. Total SO ₂ amount is sample 1
It equals SO ₂ content in, and the total SO ₂ from the total SO ₂ amount
The value obtained by subtracting the amount is equal to the amount of SO _x in the sample 1 (the amount calculated as SO ₂ is converted into the amount of SO _x ).

In the apparatus shown in FIG. 5, the SO _x converter 3 is, for example, a heating furnace containing a reducing material (for example, it is heated to about 400 ° C.), and the reducing material converts SO _x into SO ₂ . Further, for example, a chemical adsorbent is stored in the SO _x adsorber 4, and the SO _x (S
O ₃ , SO ₄ ) is adsorbed.

By the way, although SO _x is removed by adsorption in the exhaust gas measuring apparatus of FIG. 5, it may be considered to change it to another simple means. For example, Japanese Utility Model Laid-Open No. 61-108951 discloses an exhaust gas (gas) analyzing apparatus configured to supply a measurement gas to an analysis unit through a semipermeable membrane dehumidifier, rather than the semipermeable membrane dehumidifier. Electronic cooler (electronic cooler) in the measurement gas flow path on the good side
An exhaust (air) gas analyzer is provided which is provided with

[0005]

In the device of FIG. 5,
When using, for example, activated carbon as the reducing material in the heating furnace of the SO _x converter, it is necessary to frequently replace the activated carbon in order to maintain and manage the conversion efficiency from SO _x → SO ₂ in a good state. (Depending on the life of the reducing material, for example, 20 to
It is necessary to replace every 40 hours of measurement), and maintenance of the SO _x converter is complicated. Similarly, in order to maintain and manage the adsorption performance of the chemical adsorbent of the SO _x adsorber in a good state, it is necessary to frequently replace the adsorbent (depending on the life of the chemical adsorbent, for example, It is necessary to replace it every 40 to 50 hours), and the maintenance and management of the SO _x adsorber is complicated.

As described above, in the exhaust gas measuring method and apparatus of FIG. 5, the measuring accuracy of SO ₂ and SO _x is maintained and managed well unless the reducing material and the adsorbing material are frequently replaced. There is a problem that it can not be done, and daily management is very troublesome. If the above management is neglected, SO ₂ and S
The accuracy of measuring O _x is lowered, and the durability of the exhaust gas measuring device is also lowered. On the other hand, when the reducing material or the adsorbent is frequently replaced, the running cost of the reducing material or the adsorbent increases. Regarding the responsiveness of the exhaust gas measuring device, the responsiveness is apt to deteriorate because it takes time due to adsorption / desorption of the reducing material and the like, which causes a problem in the transient test.

The exhaust gas analyzer described in Japanese Utility Model Laid-Open No. 61-108951 combines a semipermeable membrane dehumidifier and an electronic cooler to adsorb moisture in the exhaust gas, and NO
It is intended to prevent measurement errors due to moisture interference even when the measured object such as _x is present at low concentration. In the exhaust gas by combining the SO _x converter and the electronic cooler. It is not intended to measure the amount of sulfur dioxide (SO ₂ ) and the amount of socks (SO _x ) of the.

The present invention is intended to solve the above-mentioned problems of the prior art, and its object is to measure exhaust gas easily and quickly, with high reliability and accuracy, and in a wide range of application. (EN) Provided is a method, and an exhaust gas measuring device having high durability and responsiveness, which is easy to maintain and maintain (maintenance-free).

[0009]

That is, the exhaust gas measuring method of the present invention is a method for measuring the amount of sulfur dioxide (SO ₂ ) and the amount of socks (SO _x ) in the exhaust gas. S in exhaust gas cooled by a cooler
A step of removing O _x and then measuring the amount of SO _{2 in the} exhaust gas; and b) heat treating the exhaust gas in a pyrolysis furnace to remove SO in the exhaust gas.
Convert _x to SO _2, then it consists of a step of measuring the SO ₂ content in the exhaust gas, is determined from the steps a) SO ₂ content in the exhaust gas, SO _x amount in the exhaust gas, step b) It is characterized by being obtained by subtracting the SO ₂ amount measured in step a) from the SO ₂ amount measured in step a). Further, the exhaust gas measuring device of the present invention is a device for measuring the amount of sulfur dioxide (SO ₂ ) and sox (SO _x ) in the exhaust gas, i) a thermal decomposition furnace for converting SO _x into SO _2. Ii) a second flow path which is a bypass path of the pyrolysis furnace, and iii) is installed on the upstream side of the pyrolysis furnace and branches the exhaust gas flow into the first flow path and the second flow path. And iv) a merging unit that is installed on the downstream side of the pyrolysis furnace and that merges the exhaust gas flows branched into the first flow path and the second flow path, and v) shared with the diverging means and / or the merging means. Flow path switching means for switching the exhaust gas flow so as to flow to the first flow path or the second flow path, and is installed in the vicinity of the branching means and / or the merging means separately from the branching means and / or the merging means. Vi) a cooler installed downstream of the confluence means, and vii) a cooler installed downstream of the cooler. And SO ₂ analyzer, characterized by comprising the city.

[0010]

The cooler for cooling the exhaust gas is not particularly limited as long as it can be used in the method and / or apparatus of the present invention. Specifically, for example, it is preferable to use an electronic cooler as the cooler because it is easy to handle and control.

When a three-way valve (solenoid valve or manual valve) is used as the flow path switching means, the flow path switching means is
It is shared with the branching unit and / or the joining unit (the flow path switching unit is the same as the branching unit and / or the joining unit). However, when a two-way valve (solenoid valve or manual valve) is used as the flow path switching means, the flow path switching means is not shared with the branching means and / or the merging means (the flow path switching means is the branching means or / Or different from the confluence means). In this case, the flow path switching means is installed in the vicinity of the branching means and / or the joining means separately from the branching means and / or the joining means. A three-way valve and a two-way valve may be used in combination.

The flow path switching means may be provided on either one of the branching means side and the merging means side, or both. Control of the flow path switching means can also be automatically controlled using, for example, a computer (for example, a personal computer).

FIG. 1 shows an embodiment of the exhaust gas measuring device of the present invention. Hereinafter, a case of carrying out the exhaust gas measuring method of the present invention using the apparatus of FIG. 1 will be described. Sample 7 containing SO ₂ and SO _x (eg automotive exhaust)
It can be branched in two directions by a three-way joint 8 (which may be a three-way switching valve), but the flow channel is switched by the flow channel switching device 12 and is flown to the line 9 or the line 10.
The line 10 is equipped with a SO _x decomposition furnace 11. Line 9 is an SO _x decomposition furnace 11 (for example, a thermal decomposition furnace)
It is a bypass path for bypassing. The sample 7 exiting the flow path switcher 12 then enters the electronic cooler 15 through the filter 13 (for example, Teflon filter) and the pump 14 (for example, Teflon diaphragm pump). A drain pot 16 and a restrictor 17 are connected to the electronic cooler 15.

First, when the flow path switch 12 is operated to allow the sample 7 to flow through the line 9, the sample 7 is cooled by the electronic cooler 15, so that SO ₃ , SO ₄ (in the sample 7) SO _x main component) is removed, but SO
_{The 2} is guided to the analyzer 18 without being removed. That is, in this case, the amount of SO ₂ (I) in the sample 7 is measured by the analyzer 18.
Can be measured.

[0015] Then, the sample 7 by operating the passage switching unit 12 when the flow through the line 10, SO _x in the sample 7 in SO _x decomposition furnace 11 is converted to SO ₂ by thermal dissociation. By guiding this to the analyzer 18, the total amount of SO ₂ and SO _x in the sample 7 is analyzed by the analyzer 18.
It can be measured as _two quantities (II).

Further, from SO ₂ amount (II) to SO ₂ amount (I)
The SO _x amount (as the total of the SO ₃ amount and the SO ₄ amount) in the sample 7 can be calculated by subtracting

[0017]

The present invention will be described in more detail with reference to the following examples. <Practicality Verification Test> In order to verify the practicality of the method and apparatus of the present invention, the apparatus of the present invention was connected to an SO _x generator,
Was measured SO _x trapping efficiency by SO _x → SO ₂ conversion efficiency and an electronic cooler according SO _x decomposition furnace.

I. Using the SO _x decomposition furnace apparatus Validation Figure 2 of the SO _x → SO ₂ conversion efficiency due experiments were conducted experimental conditions of the SO _x decomposition furnace was set as follows. Type: Ceramic electric tubular furnace ARF-40K (made by Asahi Rika SS) SO _x decomposition furnace temperature: 1200 ° C. Quartz tube shape: inner diameter 12 mm, outer diameter 20 mm, length (effective length) 500 mm Supply flow rate: 2 liters / minute temperature Controller: Time division proportional control type E5CR (manufactured by OMRON)

The apparatus shown in FIG. 2 will be briefly described below. SO _x Line 2 generated by SO _x generator 19
1 (glass tube; outer diameter 3/8 inch, inner diameter 1/8 inch;
Pass through line 22 (quartz glass tube;
Inner diameter 4 mm) and line 23 (Teflon tube; inner diameter 4 mm)
It is branched into two. Hastelloy joints are used at the branch. A line 20 (SUS pipe; 3/8 inch), which is a bypass pipe, is connected to the line 21. SO _x decomposition furnace 24 to the line 22, line 25
(Teflon tube; inner diameter 4 mm) is connected.

The flow path switch 26 (Teflon three-way solenoid valve) can switch the flow path of the test gas between the SO _x decomposition furnace 24 side and the line 23 side (bypass of the SO _x decomposition furnace 24). Following the flow path switching device 26, a line 25 (Teflon tube; inner diameter 4 mm), a filter 27 (Teflon filter; diameter 70 mm), a pump 28 (Teflon diaphragm pump), a line 25, an electronic cooler 2
9 (core tube glass, approx. 4 ° C), analyzer detector 31 (FP
D) is connected. Here, the inside of the analyzer (inside the broken line) is kept at 120 ° C. in the oven. A restrictor 30 is connected to the electronic cooler 29.

Using the apparatus of FIG. 2, the SO _x decomposition furnace 24
The SO _x → SO ₂ conversion efficiency was determined according to (the basic usage of the device of FIG. 2 is the same as that of the device of FIG. 1). The conversion efficiency was 91.5 to 94.4%, which was found to be sufficiently within the practical range.

II. SO _x (SO ₃ ,
Verification of collection performance of SO ₄ ) Using the device of FIG. 3, a) SO _x in the absence of SO ₂
The collection performance of (SO ₃ , SO ₄ ) and the collection performance of SO _x (SO ₃ , SO ₄ ) in the coexistence of SO ₂ were verified.
The apparatus shown in FIG. 3 will be briefly described below. With the mass flow meter 32, nitrogen gas containing a predetermined amount of SO ₂ (SO
The supply flow rate of ₂ / N ₂ ) is measured. Further, the mass flow meter 33 measures the supply flow rate of air. The mass flow meter 33 or the mass flow meter 32 is used depending on the case (a) or (b).

The test gas which has passed through the mass flow meter 33 or the mass flow meter 32 is continuously bubbler 34, SO.
_x generator 35, SO _x converter 36, flow path switch 3
7, filter 38, pump 39, electronic cooler 40
It is measured by an analyzer detector 42 (FPD) through (to which the restrictor 41 is connected). The basic measurement operation is the same as in the case of the device of FIG.

A) Measurement results of SO _x collection performance in the absence of SO _{2 The} results are shown in FIG. 4, area A (the sum of the SO ₃ content and SO ₄ amount) amount SO _x in a state which does not operate the and electronic cooler 40 activates the SO _x generator 35
And the region B indicates S in the state in which the SO _x generator 35 is activated and the electronic cooler 40 is activated.
The indicated value of the O _x amount (the total of the SO ₃ amount and the SO ₄ amount) is shown. The SO _x collection efficiency of the electronic cooler 40 in the region B was almost 100%.

B) SO _x (SO ₃ , S in the presence of SO ₂ )
Measurement was carried out in the same manner as in the case of O ₄ ) collection performance b). Also in this case, the SO _x collection efficiency of the electronic cooler 40 was almost 100%.

From the results of the examples, when the SO _x is collected by chemical absorption or chemisorption in the conventional exhaust gas measuring device, the collector (SO _x Adsorber) must be managed, but the electronic cooler used in the exhaust gas measuring device of the present invention only monitors the temperature, and there is no problem in life due to the use of glass material for the main part. I knew that.

[0027]

When the exhaust gas measuring method of the present invention is used, unlike the conventional exhaust gas measuring method, no SO _x reducing material or chemical absorbing material is used. Exhaust gas measurement that does not receive is possible, measurement accuracy is improved, and SO ₂ and SO _x (SO ₃ , S
The reliability of the measurement result of O ₄ ) is improved.

Since the exhaust gas measuring device of the present invention uses the SO _x decomposition furnace and the cooler, it does not require a complicated replacing operation of the reducing material and the chemical adsorbing material unlike the conventional exhaust gas measuring device, and forgets to replace it. There is no concern about deterioration in SO _x measurement accuracy due to delay in replacement or the like. Further, the apparatus of the present invention has high durability, contributes to maintenance-free operation, and further, the reaction as a whole is faster than that of the conventional apparatus, so that the measurement time is shortened. Therefore, the device of the present invention can be stably used, for example, in an exhaust gas purification catalyst evaluation test, and highly reliable measurement data can be continuously obtained, which is useful in developing the catalyst. is there. Further, the device of the present invention has a good responsiveness, so that it is useful for a transient test.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an embodiment of an exhaust gas measuring device of the present invention.

FIG. 2 is an explanatory diagram of an apparatus for verifying the conversion efficiency of SO _x to SO ₂ by the SO _x decomposition furnace.

FIG. 3 is an explanatory diagram of an apparatus for verifying SO _x collection performance by an electronic cooler.

FIG. 4 is a diagram showing measurement results of SO _x collection performance in the absence of SO ₂ when the apparatus of FIG. 3 is used.

FIG. 5 is an explanatory diagram of an example of a conventional exhaust gas measuring device.

[Explanation of symbols]

1, 7: sample 2, 12, 26, 37: flow path switch 3, 36: SO _x converter 4: SO _x adsorber 5, 14, 28, 39: pump 6, 18: analyzer 8: three-way joint 9, 10, 20, 21, 22, 23, 25: Line 11, 24: SO _x decomposition furnace 13, 27, 38: Filter 15, 29, 40: Electronic cooler 16: Drain pot 17, 30, 41: Restrictor 19, 35: SO _x generator 31, 42: Analyzer detector 32, 33: Mass flow meter 34: Bubbler

Front page continuation (72) Inventor Keiichi Furukawa 3-5-8 Minamisenba, Chuo-ku, Osaka City, Osaka Prefecture Koyo Seiko Co., Ltd. Chichi No. 1 Within Farm Tech Co., Ltd. (56) Reference JP-A-7-191012 (JP, A) JP-A-54-71690 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) ) G01N 31/00 G01N 31/12

Claims (2)

(57) [Claims] 1. A method for measuring the amount of sulfur dioxide (SO ₂ ) and the amount of socks (SO _x ) in exhaust gas, which comprises: a) cooling the exhaust gas with a cooler to obtain S in the exhaust gas.
A step of removing O _x and then measuring the amount of SO _{2 in the} exhaust gas; and b) heat treating the exhaust gas in a pyrolysis furnace to remove SO in the exhaust gas.
Convert _x to SO _2, then it consists of a step of measuring the SO ₂ content in the exhaust gas, is determined from the steps a) SO ₂ content in the exhaust gas, SO _x amount in the exhaust gas, step b) An exhaust gas measuring method, which comprises: subtracting the SO ₂ amount measured in step a) from the SO ₂ amount measured in step a). 2. An apparatus for measuring the amount of sulfur dioxide (SO ₂ ) and sox (SO _X ) in exhaust gas, which is i) a first flow path equipped with a pyrolysis furnace for converting SO _X into SO _2. Ii) a second flow path that is a bypass path of the pyrolysis furnace, iii) a branching unit that is installed on the upstream side of the pyrolysis furnace and that branches the exhaust gas flow into a first flow path and a second flow path, and iv ) Is installed on the downstream side of the thermal decomposition furnace, and is installed in common with the merging means for combining the exhaust gas streams branched into the first flow path and the second flow path, and v) the branching means and / or the merging means,
Alternatively, a flow path switching means, which is installed in the vicinity of the branching means and / or the merging means separately from the branching means and / or the merging means, and switches the exhaust gas flow to the first flow path or the second flow path, vi) the merging Installed downstream of the means to cool the exhaust gas.
An exhaust gas measuring device comprising: a cooler for removing SO _X in the exhaust gas by vii) and a SO ₂ analyzer installed on the downstream side of the vii) cooler.