JP2016036773A - Exhaust gas treatment method and exhaust gas treatment device of coal tar utilization facility - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exhaust gas treatment method and an exhaust gas treatment device of coal tar utilization facility capable of removing odors by removing the coal tar component efficiently in the exhaust gas.SOLUTION: The exhaust gas treatment method of a coal tar utilization facility is adopted which comprises a gas pre-cooling step removing the coal tar component from the exhaust gas, by pre-cooling the exhaust gas containing the coal tar component and a gas cooling step removing the coal tar component remaining in the exhaust gas by cooling the exhaust gas after the gas pre-cooling step, and keeps the exhaust gas temperature at the end of the gas cooling process at the temperature lower than 5°C, by controlling the exhaust gas temperature at the end of the gas pre-cooling process to lower than 10°C and higher than 5°C.SELECTED DRAWING: None

Description

  The present invention relates to an exhaust gas treatment apparatus and an exhaust gas treatment method that use cooling for exhaust gas discharged from a tar utilization facility.

  The exhaust gas from factories that handle tar is uncomfortable for most people, and even if trace amounts of odorous components are contained in the exhaust gas, it can be a problem in residential areas. As countermeasures against such odors, there are various deodorizing methods. As examples of deodorizing methods, spraying of a deodorizing agent, removal of deodorizing components by a catalyst, and deodorizing by a combustion method are generally known.

  The deodorizing method using a deodorizer has a problem that tar is a mixture of various substances and is not a uniform substance, so that a deodorant dedicated to tar cannot be produced and the effect is insufficient. In addition, in the deodorizing method using a catalyst, the catalyst is contaminated with tar, so that it is necessary to periodically remove the tar by catalytic combustion, and in addition, there is a possibility that an odor is generated during the removing operation. .

  On the other hand, with regard to deodorization by the combustion method, for example, Patent Document 1 discloses a direct combustion type deodorizing apparatus that guides exhaust gas to a combustion chamber in which a gas burner or the like is ignited and re-combusts the exhaust gas. However, in the combustion method using exhaust gas containing tar, a part of the sublimable substance may be discharged without being burned. Further, in order to sufficiently re-burn the exhaust gas generated in the tar handling facility, a structure in which the exhaust gas passes through the combustion chamber is required. In this case, considering the gas flow rate and the like, it is necessary to prepare a very large combustion chamber, and there is a problem that the equipment cost becomes expensive.

  As a technique for solving this problem, Patent Document 2 discloses that exhaust gas is once cooled in a gas cooling unit, the tar content is condensed, the removed tar is received in a tray unit, and flows down toward the combustion unit for combustion. The technology is described.

Japanese Unexamined Patent Publication No. 63-197574 JP-A-5-131114

  The condensation / separation means for tar by cooling in the deodorization method described in Patent Document 2 does not provide a method for setting cooling conditions or controlling based on the concentration measurement results of various odor molecules contained in tar. Therefore, depending on the cooling conditions, there was a problem that some of the odor molecules in tar were diffused to the atmosphere as they were without condensation / separation. On the other hand, if excessive cooling is performed to prevent this, there is a problem that the operating cost increases or energy is wasted.

  The present invention has been made in view of the above problems in the prior art, and an exhaust gas treatment method and an exhaust gas treatment apparatus for a tar utilizing facility capable of efficiently removing a odor by removing a tar component in the exhaust gas. It is an issue to provide.

The configuration of the present invention made to solve the above problems is as follows.
(1) a gas precooling step of precooling exhaust gas containing a tar component to remove the tar component from the exhaust gas;
A gas cooling step of cooling the exhaust gas after the gas pre-cooling step and removing the tar component remaining in the exhaust gas,
An exhaust gas treatment method for a tar utilizing facility, characterized in that an exhaust gas temperature at the end of the gas precooling step is 5 ° C. or more and 10 ° C. or less, and an exhaust gas temperature at the end of the gas cooling step is 5 ° C. or less.
(2) In the tar component in the exhaust gas before the gas precooling step, in mass concentration,
Toluene: 100 ppm or less,
Xylene: 100 ppm or less,
Phenol: 10 ppm or less,
Inden: 10 ppm or less,
Indan: 10 ppm or less,
o-cresol, m-cresol, p-cresol: 2 ppm or less each,
Naphthalene: 40 ppm or less,
Methylnaphthalene: 40 ppm or less,
1 or more types of odor components are contained, The waste gas processing method of the tar utilization equipment as described in (1) characterized by the above-mentioned.
(3) Fractionating part of the exhaust gas after the gas precooling step and / or after the gas cooling step,
Measure the concentration of odorous components in the collected exhaust gas,
The tar utilization according to (1) or (2), wherein a cooling condition of the exhaust gas in the gas preliminary cooling step and / or the gas cooling step is controlled based on a concentration of the odor component of the exhaust gas. Exhaust gas treatment method for equipment.
(4) In the gas precooling step, the inner diameter of the precooling pipe through which the exhaust gas flows is 50 mm or more,
In the gas cooling step, the inner diameter of the cooling pipe through which the exhaust gas flows is 25 mm or more,
The exhaust gas treatment method for a tar utilizing facility according to any one of (1) to (3), wherein a ratio of an inner diameter of the preliminary cooling pipe to an inner diameter of the cooling pipe is 2: 1 or more.
(5) A gas analysis method for measuring a concentration of an odor component in the exhaust gas,
The exhaust gas separated into a vacuum exhausted ionization chamber is guided, the exhaust gas is irradiated with laser light in the ionization chamber to ionize the odor component, and the ionized odor component is guided to a mass analyzer to determine its mass. The method for treating exhaust gas from tar using facilities as described in (3) or (4), wherein the method is laser ionization mass spectrometry.
(6) exhaust gas flow path;
A gas precooling section that is provided in the middle of the exhaust gas flow path and precools the exhaust gas containing the tar component to remove the tar component from the exhaust gas;
A gas cooling unit that is provided downstream of the gas preliminary cooling unit of the exhaust gas flow path, cools the exhaust gas, and removes the tar component remaining in the exhaust gas from the exhaust gas,
The gas precooling section can cool the temperature of the exhaust gas at the outlet to 5 ° C. or less,
The gas cooling unit is an exhaust gas treatment device for a tar utilizing facility capable of cooling the temperature of the exhaust gas at the outlet to 5 ° C to 10 ° C.
(7) a sorting pipe branched from the gas flow path on the outlet side of the gas preliminary cooling unit;
A gas analyzer that is connected to the sorting pipe and measures the concentration of an odorous component contained in the tar component of the exhaust gas separated from the exhaust gas flow path via the sorting pipe;
A cooling control unit that controls cooling conditions of the gas cooling unit and / or the gas preliminary cooling unit based on the concentration of the odor component;
The exhaust gas treatment apparatus for a tar utilization facility according to (6), characterized in that
(8) The inner diameter of the preliminary cooling pipe forming the exhaust gas flow path in the gas preliminary cooling section is 50 mm or more,
In the gas cooling part, the inner diameter of the cooling pipe forming the exhaust gas flow path is 25 mm or more,
The ratio of the inner diameter of the preliminary cooling pipe to the inner diameter of the cooling pipe is 2: 1 or more, the exhaust gas treatment apparatus for a tar utilizing facility according to (6) or (7).
(9) The gas analyzer includes a vacuum ultraviolet laser light source, an ionization chamber that ionizes the odor component by irradiating the collected exhaust gas with laser light oscillated from the vacuum ultraviolet laser light source, and the odor component. An exhaust gas treatment apparatus for a tar utilizing facility according to (7) or (8), characterized in that the apparatus is a laser ionization mass spectrometer equipped with a mass analyzer for measuring the mass of the tar.

ADVANTAGE OF THE INVENTION According to this invention, the waste gas processing method and waste gas processing apparatus of the tar utilization equipment which can remove the tar component in waste gas efficiently can be provided.
In particular, during treatment using cooling of exhaust gas generated from tar utilization facilities, even if unsteady fluctuations in operating conditions occur, the odor component contained in the tar component is reliably reduced below the olfactory threshold and maintained. It becomes possible. Further, exhaust gas treatment can be performed with a minimum operation cost.

FIG. 1 is a schematic view showing an exhaust gas treatment apparatus according to an embodiment of the present invention. FIG. 2 is a schematic diagram showing a gas precooling section provided in the exhaust gas treatment apparatus according to the embodiment of the present invention. FIG. 3 is a schematic view showing another example of the exhaust gas treatment apparatus according to the embodiment of the present invention. FIG. 4 is a schematic diagram showing another example of the gas precooling section provided in the exhaust gas treatment apparatus according to the embodiment of the present invention. FIG. 5 is a schematic diagram showing still another example of the gas precooling section provided in the exhaust gas treatment apparatus according to the embodiment of the present invention. FIG. 6 is a schematic diagram showing a gas analyzer and a cooling control unit provided in the exhaust gas processing apparatus according to the embodiment of the present invention. FIG. 7 is a schematic diagram showing a gas analyzer provided in the exhaust gas treatment apparatus according to the embodiment of the present invention. FIG. 8 is a graph showing the relationship between the exhaust gas temperature and the concentration of odor components at the outlet of the gas cooling unit provided in the exhaust gas treatment apparatus according to the embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In steelworks, when producing coke from coal, exhaust gas containing tar components is generated as a by-product. Equipment for handling tar components (hereinafter referred to as tar utilization equipment) in steelworks is equipped with deodorizing equipment for treating exhaust gas containing tar components. An example of the tar utilization facility targeted by the present embodiment includes a coal pretreatment facility including a step of adding tar to pulverized coal for the production of blast furnace coke. In this case, the amount of tar added to the coal is 5 to 15% by weight.

  By the way, various odor components are contained in the tar component in the exhaust gas discharged from the tar utilization facility. In many tar odors, the influence of odor components having a larger mass number than benzene such as naphthalene and indene is large. The olfactory thresholds of the main odor components contained in the tar component are the concentrations shown in Table 1, respectively. Among the odor components shown in Table 1, there are phenol, o-, m-, p-cresol, indene, indane, naphthalene, and 2-methylnaphthalene as molecules that have a particularly low olfactory threshold and are highly influenced by odor. . It is necessary to control the odor component in the exhaust gas discharged from the tar utilization facility to the olfactory threshold value or less in Table 1.

  In the present embodiment, the exhaust gas capable of deodorizing exhaust gas is such that when the concentration of each odorous substance in the exhaust gas before deodorization is an exhaust gas temperature of 55 ° C., toluene and xylene are each 100 ppm or less, and phenol, indene, and indane are each 10 ppm. Hereinafter, it is an exhaust gas in which o-, m-, and p-cresol are each 2 ppm or less, and naphthalene and methylnaphthalene are each 40 ppm or less. In the investigation by the present inventors, there was no tar utilization facility that required exhaust of a level exceeding the above standard, and therefore the present invention can be applied to almost all tar utilization facilities.

  In order to remove a tar component containing an odor component in the exhaust gas (hereinafter sometimes simply referred to as tar), it is necessary to cool the exhaust gas and condense the tar. Here, in order to cool the exhaust gas with high efficiency in order to condense the tar with the odor component, it is necessary to increase the contact area between the gas cooling part for cooling the exhaust gas and the exhaust gas and perform heat exchange efficiently. For example, a structure in which the gas flow path is a small-diameter pipe and the length of the small-diameter pipe is increased so that the exhaust gas passing through the small-diameter pipe can be cooled is suitable. However, when exhaust gas containing high-concentration tar is cooled, there is often a problem that a large amount of tar components contained in the exhaust gas condense in the small-diameter pipe and clog the small-diameter pipe. Therefore, in the present embodiment, a mechanism provided with a gas precooling unit that removes most of the tar components contained in the exhaust gas in advance before the exhaust gas flows into the small diameter pipe of the gas cooling unit is adopted.

  FIG. 1 schematically shows an exhaust gas treatment apparatus 1 according to an embodiment of the present invention as an example of a deodorization facility for tar utilization facilities. An exhaust gas treatment apparatus 1 shown in FIG. 1 is provided in a path for guiding and discharging exhaust gas from a tar treatment facility, for example. The exhaust gas treatment apparatus 1 in FIG. 1 is provided on the downstream side of the exhaust gas flow path 2, the gas precooling section 3 provided in the middle of the exhaust gas flow path 2, and the gas precooling section 3 of the exhaust gas flow path 2. And a gas cooling unit 4. The exhaust gas treatment device 1 further includes a gas analyzer 5 and a cooling control unit (not shown).

  As shown in FIGS. 1 and 2, the gas precooling section 3 includes a precooling pipe 3 a that forms the gas flow path 2 and a coolant pipe 3 b that is disposed on the outer periphery of the precooling pipe 3 a. The inner diameter of the preliminary cooling pipe 3a is 50 mm or more. The coolant pipe 3b is spirally wound around the outer peripheral surface of the preliminary cooling pipe 3a along the longitudinal direction of the preliminary cooling pipe 3a. The flow direction of the coolant flowing through the coolant pipe 3b is opposite to the flow direction of the exhaust gas. An exhaust gas introduction pipe 3c for introducing exhaust gas is connected to the preliminary cooling pipe 3a. The exhaust gas introduction pipe 3 c also constitutes a part of the exhaust gas flow path 2. Further, the preliminary cooling pipe 3a is provided with a discharge port 3d (exit of the gas preliminary cooling unit 3) for discharging the exhaust gas after cooling. A thermometer (not shown) for measuring the temperature of the exhaust gas is installed in the vicinity of the discharge port 3d. Examples of the thermometer include a thermocouple and a resistance thermometer.

  The preliminary cooling pipe 3a is provided with a drain part 3e. The drain part 3e is configured to store a condensed substance such as tar condensed in the preliminary cooling pipe 3a. In addition, a drain cock 3f for discharging condensed matter such as tar collected in the drain portion 3e to the outside is attached to the drain portion 3e.

  In the gas precooling section 3, the exhaust gas introduced from the exhaust gas introduction pipe 3c is cooled in the precooling pipe 3a to condense most of the tar components in the exhaust gas. In the gas preliminary cooling unit 3, the cooling medium flowing through the cooling medium pipe 3b by the cooling control unit so that the temperature of the exhaust gas discharged from the discharge port 3d of the preliminary cooling pipe 3a is in the range of 5 ° C to 10 ° C. The flow rate is adjusted.

  Next, as shown in FIG. 1, the gas cooling unit 4 includes a cooling pipe 4a that forms a gas flow path, and a cooling tank 4b that houses the cooling pipe 4a. The cooling pipe 4a is spirally wound and accommodated in the cooling tank 4b. The inner diameter of the cooling pipe 4a is 25 mm or more. The cooling pipe 4a is provided with a plurality of drain cocks 4f. The drain cock 4f is installed to discharge tar collected at a low position of the cooling pipe 4a due to the action of gravity. The drain cock 4f is preferably installed at a position where tar is easily removed. In the example shown in FIG. 1, the drain cock 4 f is provided at a plurality of locations where the height of the cooling cock 4 a spirally wound is reduced. Further, a refrigerant can be introduced into the cooling tank 4b.

  In the gas cooling unit 4, the exhaust gas introduced from the gas preliminary cooling unit 3 is cooled in the cooling pipe 4a, and the remaining tar component in the exhaust gas is condensed. In the gas cooling unit 4, the flow rate of the refrigerant introduced into the cooling tank 4 b is adjusted by the cooling control unit so that the temperature of the exhaust gas discharged from the discharge port 4 d of the cooling pipe 4 a is 5 ° C. or less.

  Further, it is preferable that the inner diameter of the preliminary cooling pipe 3a is 50 mm or more, the inner diameter of the cooling pipe 4a is 25 mm or more, and the ratio between the inner diameter of the preliminary cooling pipe 3a and the inner diameter of the cooling pipe 4a is 2: 1 or more. This is preferable in that the blockage of the preliminary cooling pipe 3a in the cooling unit 3 can be reliably prevented.

  Further, the inner diameter of the cooling pipe 4a of the gas cooling unit 4 is suitably about 10 to 50 mm in order to increase the heat exchange porosity between the exhaust gas and the refrigerant. On the other hand, the cross-sectional area of the gas flow path of the pre-cooling pipe 3a of the gas pre-cooling section 3 is preferably equal to or larger than the area of a circle having a diameter of 50 mm in order to prevent clogging with a tar component.

  The gas preliminary cooling unit 3 and the gas cooling unit 4 are connected by a connecting pipe 7. The connecting pipe 7 constitutes a part of the gas flow path 2 and is included in the gas cooling unit 4. One end of the connection pipe 7 is connected to the discharge port 3d of the preliminary cooling pipe 3a of the gas preliminary cooling section 3. The other end of the connection pipe 7 is connected to one end of the cooling pipe 4 a of the gas cooling unit 4. The discharge port 3 d of the gas preliminary cooling unit 3 is disposed at a position lower than one end of the cooling pipe 4 a of the gas cooling unit 4. For this reason, the connecting pipe 7 is inclined and arranged so as to rise obliquely from the gas preliminary cooling unit 3 toward the gas cooling unit 4. Thereby, obstruction | occlusion of the connecting pipe 7 can be prevented. Further, the inner diameter of the connecting pipe 7 is smaller than the inner diameter of the preliminary cooling pipe 3a, and preferably the same inner diameter as the inner diameter of the cooling pipe 4a. By making the inner diameter of the connecting pipe 7 smaller than the inner diameter of the preliminary cooling pipe 3a, the cooling capacity of the exhaust gas can be improved.

  Further, an exhaust pipe 8 is connected to the other end of the cooling pipe 4 a of the gas cooling section 4. The exhaust pipe 8 constitutes a part of the gas flow path 2. A gas analyzer 5 is connected in the middle of the exhaust pipe 8. The gas analyzer 5 samples a part of the exhaust gas flowing through the exhaust pipe 8 and analyzes the odor component in the exhaust gas.

Next, the operation of the exhaust gas treatment apparatus 1 shown in FIG. 1 will be described.
First, the exhaust gas discharged from the tar utilization facility is introduced into the gas preliminary cooling unit 3. The exhaust gas contains a tar component. Toluene: 100 ppm or less, xylene: 100 ppm or less, phenol: 10 ppm or less, indene: 10 ppm or less, indane: 10 ppm or less, o-cresol, m-cresol, p -Cresol: 2 ppm or less each, naphthalene: 40 ppm or less, methyl naphthalene: 40 ppm or less, any one or more odor components are included. The exhaust gas introduced into the gas preliminary cooling unit 3 is cooled by the cooling medium flowing through the cooling medium pipe 3b in the preliminary cooling pipe 3a. At this time, it cools so that the temperature of exhaust gas may be 5-10 degreeC in the thermometer in the discharge port 3d of the gas preliminary cooling part 3. FIG. When the exhaust gas temperature by the thermometer deviates from the range of 5 to 10 ° C., the flow rate of the coolant flowing through the coolant pipe 3b is adjusted by a cooling control unit (not shown) based on the measurement result of the thermometer, and the temperature of the exhaust gas Is controlled to be 5 to 10 ° C. Hereinafter, the gas precooling step in the gas precooling unit 3 and the gas cooling step in the gas cooling unit 4 will be described.

(Gas pre-cooling process)
The gas precooling unit 3 condenses and separates most of the tar in the exhaust gas, and the heat exchange efficiency is not as high as that of the gas cooling unit 4 because the precooling pipe 3a has a relatively large inner diameter of 50 mm or more. However, if the exhaust gas temperature at the discharge port 3d of the gas precooling section 3 is set to 10 ° C. or less, most of the odor components contained in the exhaust gas condense due to the vapor pressure and the like, and the concentration of the odor components in the exhaust gas is precooled. It can be reduced to the previous tenth. The exhaust gas temperature at the discharge port 3d of the gas precooling unit 3 is preferably 5 ° C. or more and 10 ° C. or less. However, if the cooling time in the gas precooling 3 is 4 seconds or more, the discharge port of the gas precooling unit 3 The exhaust gas temperature in 3d becomes 8 ° C. to 10 ° C., and 90% or more of odor components can be removed. In particular, when the concentration of the odor component in the exhaust gas is high, the removal rate of the odor component in the exhaust gas is 95% or more. The odor component removed by the gas precooling section 3 flows down to the drain section 3e together with tar in a solid or liquid state.

  As described above, among odor components in exhaust gas, odor components such as phenol, o-, m-, p-cresol, indene, indane, naphthalene, and 2-methylnaphthalene, which have a great influence on odor even in a trace amount, are 90%. The degree becomes solid or liquid in the gas precooling section 3 and is removed from the exhaust gas together with other tar components and flows down to the drain section 3e. Tar containing odor components stored in the drain part 3e can be taken out from the drain cock 3f. The exhaust gas containing the odor component that could not be removed by the gas preliminary cooling unit 3 is sent to the gas cooling unit 4 through the connection pipe 7.

  The connecting pipe 7 is inclined so as to rise obliquely from the gas preliminary cooling unit 3 toward the gas cooling unit 4. Since the exhaust gas flowing through the connecting pipe 7 is immediately after being discharged from the gas preliminary cooling unit 3, the temperature of the exhaust gas flowing through the connecting pipe 7 is 10 ° C. or less, and is gradually cooled as the exhaust gas moves toward the cooling pipe 4a. Temperature drops. For this reason, while exhaust gas is sent to the gas cooling part 4 through the connection pipe 7, condensation of the tar containing the odor component contained in the exhaust gas proceeds in the connection pipe 7. Since the inner diameter of the connection pipe 7 is the same as that of the cooling pipe 4a and is smaller than the inner diameter of the preliminary cooling pipe 3a, the connection pipe 7 is liable to be clogged with condensed matter. In this embodiment, since the connecting pipe 7 is inclined obliquely, tar containing condensed odor components adheres to the inner wall of the connecting pipe 7 and then flows down to the gas precooling section 3 side through the connecting pipe 7. Thus, the connection pipe 7 is prevented from being blocked. Here, if there is a vertically rising portion in a part of the connecting pipe 7, tar accumulates at the lowermost portion of the vertically rising portion, which is not preferable. Further, when the connecting pipe 7 is directed obliquely downward toward the gas cooling unit 4, tar containing an odor component condensed in the connecting pipe 7 flows into the gas cooling unit 4, and the gas in the gas cooling unit 4 Since the cooling pipe 4a which is the flow path 2 is blocked, it is not preferable. By disposing the connecting pipe 7 so as to face obliquely upward toward the gas cooling section 4, tar containing most of the odor component can flow down to the drain section 3 e of the gas preliminary cooling section 3. Can prevent clogging.

(Gas cooling process)
Next, the exhaust gas introduced into the gas cooling unit 4 from the connection pipe 7 is cooled by the cooling medium flowing in the gas cooling tank 4b in the cooling pipe 4a. At this time, the exhaust gas is cooled so that the temperature of the exhaust gas is 5 ° C. or less in the thermometer at the discharge port 4 d of the gas cooling unit 4. When the exhaust gas temperature in the thermometer exceeds 5 ° C, the flow rate of the coolant flowing through the gas cooling tank 4b is adjusted by a cooling control unit (not shown) based on the measurement result of the thermometer, and the exhaust gas temperature exceeds 5 ° C. Do not.

As the exhaust gas cooling in the gas cooling unit 4 is increased, the odor component removal rate is increased. However, excessive cooling increases not only the cooling cost but also the cooling pipe 4a is easily clogged with condensed matter and moisture. When the exhaust gas temperature at the discharge port 4d of the gas cooling unit 4 becomes 0 ° C. or less, moisture condenses and the frequency of troubles due to the blockage of the cooling pipe 4a increases remarkably. Therefore, the exhaust gas may be cooled in the gas cooling unit 4 so that the exhaust gas temperature at the discharge port 4d of the gas cooling unit 4 is 0 ° C. or higher. In order to reduce the frequency of maintenance and replacement of the cooling pipe 4a and reduce the concentration of odorous components below the olfactory threshold shown in Table 1, the exhaust gas temperature at the outlet 4d of the gas cooling unit 4 is 3 ° C. or more and 5 It is more preferable that the temperature be set to ° C. In addition, when exhaust gas is cooled until the exhaust gas temperature is less than 2 ° C., the cooling pipe 4a is easily clogged. This is because the amount of condensation of odorous components to be removed has increased more than necessary. It is considered that one of the causes is that the substance other than the odor component is condensed.
In this embodiment, the deodorizing effect that the concentration of the odorous component in the exhaust gas is reduced to 1/100 to 1/1000 is obtained by cooling the exhaust gas temperature at the discharge port 4d of the gas cooling unit 4 to 5 ° C. or less.

  Since the tar containing the odor component accumulated in the cooling pipe 4a moves to a lower position of the cooling pipe 4a due to the action of gravity, the drain cock 4f may be opened and discharged from the cooling pipe 4a. In the present embodiment, 90 to 95% of the tar component in the exhaust gas is removed by the gas precooling unit 3, and the tar component that cannot be removed remains as the remaining tar component. The residual tar is removed from the exhaust gas in the gas cooling unit 4. Even if the residual tar content in the exhaust gas after passing through the gas preliminary cooling unit 3 is very small, The tar component gradually accumulates in the cooling pipe 4a, and finally the problem of clogging the cooling pipe 4a occurs. Therefore, by opening the drain cock 4f to discharge tar, it is possible to extend the time until the piping is closed.

  The exhaust gas from which tar containing odor components has been removed by the gas cooling unit 4 is discharged to the atmosphere through the exhaust pipe 8. In the middle of the exhaust pipe 8, the concentration of the odor component is measured by the gas analyzer 5. The measurement result of the gas analyzer 5 is output to the cooling control unit. When the measurement result of the odor component exceeds the olfactory threshold shown in Table 1, the cooling control unit adjusts the cooling condition of one or both of the gas pre-cooling unit 3 and the gas cooling unit 4 and Increase the removal efficiency of odor components. Moreover, when the measurement result of an odor component does not exceed the olfactory threshold shown in Table 1, the cooling control unit maintains the cooling conditions of the gas precooling unit 3 and the gas cooling unit 4 without changing them.

  As described above, according to this embodiment, the gas precooling unit 3 precools the exhaust gas in the range of 5 ° C. to 10 ° C., so that most of the tar containing the odor component is specifically 90%. % Or more can be removed. Further, by cooling the exhaust gas to 5 ° C. or less by the gas cooling unit 4, the concentration of the odor component in the exhaust gas can be reduced to the olfactory threshold value or less, and the odor of the exhaust gas can be eliminated. Further, since most of the tar component is removed in the gas precooling section 3, there is no possibility that the clogging of the tar immediately occurs in the cooling pipe 4a of the gas cooling section 4.

  In addition, since the exhaust gas is pre-cooled by the gas pre-cooling section 3 having the pre-cooling pipe 3a having a larger inner diameter than the cooling pipe 4a of the gas cooling section 4, most of the tar contained in the exhaust gas is removed. There is no possibility that the precooling pipe 3a is blocked by a condensed substance such as tar. In particular, by setting the inner diameter of the preliminary cooling pipe 3a to 50 mm or more, the inner diameter of the cooling pipe 4a to 25 mm or more, and the ratio of the inner diameter of the preliminary cooling pipe 3a to the inner diameter of the cooling pipe 4a to 2: 1 or more, The blockage of the preliminary cooling pipe 3a in the cooling unit 3 can be reliably prevented.

  Further, the concentration of the odor component in the exhaust gas after passing through the gas cooling unit 4 is analyzed by the gas analyzer 5, and based on the result, the cooling control unit performs either or both of the gas precooling unit 3 and the gas cooling unit 4. Since the cooling condition is controlled, the concentration of the odor component in the exhaust gas can always be reduced below the olfactory threshold. Control of the cooling condition based on the concentration of the odor component is particularly effective when the concentration of the odor component in the exhaust gas varies.

  The embodiment of the present invention has been described above. However, the present invention may use modified examples described below.

  In FIG. 3, the modification of the waste gas processing apparatus 21 is shown. In the modified example of FIG. 3, a trap 11 is provided in the exhaust pipe 8 between the gas cooling unit 4 and the gas analyzer 5. The trap 11 includes a metal plate 11a disposed on the exhaust gas flow path and a trap body 11b that accommodates the metal plate 11a. The trap body 11 b communicates with the exhaust pipe 8. The metal plate 11a is disposed in the trap body 11b so that the plate surface is positioned on the extension of the exhaust pipe 8. A gap is provided between the outer peripheral edge 11c of the metal plate 11a and the trap body 11b, and the exhaust gas colliding with the metal plate 11a passes through this gap and is discharged from the trap 11 to the exhaust pipe 8. ing. The trap body 11b is provided with a drain cock 11e.

  The exhaust gas immediately after being discharged from the gas cooling unit 4 collides with the metal plate 11 a in the trap 11. The tar remaining in the exhaust gas condenses on the metal plate 11a due to the impact at the time of the collision. The tar condensed on the metal plate 11a is stored in the lower part of the trap body 11b by the action of gravity, and is discharged to the outside from the drain cock 11e. Here, since the temperature of the exhaust gas discharged from the gas cooling unit 4 is 5 ° C. or less, the metal plate 11a is cooled by the collision of the exhaust gas. When the constituent member of the trap body 11b is a heat insulating material, the metal plate 11a is insulated from the external environment of the trap 11, and the temperature of the metal plate 11a in the trap body 11b is substantially the same as the exhaust gas temperature (5 ° C. The following): Thus, the odor component condensed in the trap 11 is not vaporized again, and the exhaust gas that has passed through the trap 11 is diffused into the atmosphere as an exhaust gas having a concentration of the odor component equal to or lower than the odor threshold.

  As described above, the concentration of the odor component in the exhaust gas can be further reduced by providing the trap 11 in the exhaust pipe 8.

  Next, FIG. 4 shows another example of the gas preliminary cooling unit 23. In the gas precooling section 23 shown in FIG. 4, the precooling pipe 23a forming the gas flow path 2 is a double pipe composed of an inner pipe 23b and an outer pipe 23c. A cooling medium introduction pipe 23d and a lead-out pipe 23g are connected to the preliminary cooling pipe 23a. The preliminary cooling pipe 23a is provided with a drain portion 23e having a drain cock 23f. The inner diameter of the inner tube 23b is 50 mm or more. The exhaust gas passes through the inner pipe 23b, and the cooling medium flows in the gap between the inner pipe 23b and the outer pipe 23c. The flow direction of the coolant flowing between the inner tube 23b and the outer tube 23c is opposite to the flow direction of the exhaust gas. With this configuration, heat exchange is performed between the cooling medium and the exhaust gas to cool the exhaust gas.

  FIG. 5 shows still another example of the gas preliminary cooling unit 33. The gas precooling section 33 shown in FIG. 5 includes a precooling pipe 33a that forms the gas flow path 2, and a coolant pipe 33b that is disposed inside the precooling pipe 33a. The inner diameter of the preliminary cooling pipe 33a is 50 mm or more. The cooling medium pipe 33b is spirally wound along the longitudinal direction of the preliminary cooling pipe 33a. The flow direction of the coolant flowing through the coolant pipe 33b is opposite to the flow direction of the exhaust gas. The preliminary cooling pipe 33a is provided with a drain portion 33e having a drain cock 33f. With this configuration, heat exchange is performed between the cooling medium and the exhaust gas to cool the exhaust gas.

  Even in the gas precooling sections 23 and 33 shown in FIGS. 4 and 5, the exhaust gas can be cooled to a range of 5 ° C. to 10 ° C., and most of the tar containing odor components in the exhaust gas is removed. be able to.

  In addition, the cooling method by the gas cooling part 4 and the gas preliminary cooling part 3 is not limited to what was demonstrated in FIG. For example, a cooling method using a solvent or the like, or a cooling method using dry ice can be used.

Next, another example of the cooling control method by the gas analyzer 5 and the cooling control unit 6 will be described with reference to FIG.
FIG. 6 shows another example of the exhaust gas treatment apparatus. An exhaust gas treatment device 41 shown in FIG. 6 is provided on the downstream side of the exhaust gas flow path 2, the gas precooling section 3 provided in the middle of the exhaust gas flow path 2, and the gas precooling section 3 of the exhaust gas flow path 2. The gas cooling unit 4, the gas analyzer 5 for measuring the odor component concentration in the exhaust gas, and the cooling control unit 46 are configured.

  As shown in FIG. 6, the first branch pipe 47 is connected to the connection pipe 7 that connects the gas precooling section 3 and the gas cooling section 4. A second branch pipe 48 is connected to the exhaust pipe 8 on the downstream side of the gas cooling unit 4. The first and second branch pipes 47 and 48 are connected to the gas analyzer 5. With such a configuration, the odor component concentration in the exhaust gas after passing through the gas preliminary cooling unit 3 or the odor component concentration in the exhaust gas after passing through the gas cooling unit 4 can be introduced into the gas analyzer 5. . In FIG. 6, the connecting pipe 7 of the gas precooling unit 3 and the gas cooling unit 4 is shown to be horizontal, but actually, it is arranged obliquely as in FIGS. 1 and 2.

  The gas analyzer 5 is connected to the cooling control unit 46, and can output the measurement result of the odor component concentration to the cooling control unit 46. The cooling control unit 46 can control the cooling condition of one or both of the gas precooling unit 3 and the gas cooling unit 4 based on the measurement result of the odor component concentration.

Next, the operation of the exhaust gas treatment device 41 shown in FIG. 6 will be described.
First, a part of the exhaust gas treated by the gas precooling unit 3 is sampled from the first branch pipe 47, and the odor component concentration is analyzed by the gas analyzer 5. The remaining exhaust gas is sent to the gas cooling unit 4 for processing. The odor component concentration measured in the gas analyzer 5 is output to the cooling control unit 46. The cooling control unit 46 controls the flow rate of the coolant in the gas preliminary cooling unit 3 or the gas cooling unit 4 according to the control program based on the input information of the component concentration.

  As specific contents of the control, for example, when the odor component concentration in the exhaust gas that has passed through the gas preliminary cooling unit 3 exceeds the control threshold, the exhaust gas temperature at the discharge port 3d of the gas preliminary cooling unit 3 is set to 5 ° C to 5 ° C. By adjusting to a lower temperature range within the range of 10 ° C., the odor component concentration in the exhaust gas after passing through the gas precooling section 3 is set to a control threshold value or less. The lower temperature range is, for example, a range where the exhaust gas temperature is 5 to 7 ° C. As control threshold values of the odor component concentration in the exhaust gas, toluene: 10 ppm, xylene: 10 ppm, phenol: 1 ppm, indene: 1 ppm, indane: 1 ppm, o-, m-, p-cresol are each 0.2 ppm, naphthalene: 4 ppm And methylnaphthalene: 4 ppm. Of these odor components, the above control may be performed when even one type exceeds the control threshold.

  If the measurement result of the exhaust gas by the gas analyzer 5 is less than or equal to the control threshold value, the exhaust gas temperature at the discharge port 3d of the gas precooling unit 3 is set within a range of 5 ° C to 10 ° C in consideration of power consumption and the like. By controlling to a higher temperature range, power consumption may be suppressed. The higher temperature range is, for example, in the range of 8 to 10 ° C.

  Further, not only the cooling conditions of the cooling units 3 and 4 are adjusted based on the odor component concentration of the exhaust gas after passing through the gas preliminary cooling unit 3, but also a part of the exhaust gas after passing through the gas cooling unit 4 is second branched. When the odor component concentration in the separated exhaust gas is measured by the gas analyzer 5 and the odor component concentration exceeds the olfactory threshold shown in Table 1, the gas precooling unit 3 and the gas cooling unit 4 are separated. Adjustments may be made to further increase one or both of the cooling conditions. This reliably prevents the odor component concentration in the exhaust gas from exceeding the olfactory threshold.

  According to the exhaust gas treatment device 41 shown in FIG. 6, more detailed and accurate control of the cooling conditions is possible, and optimal control is always possible even when an unsteady fluctuation of the exhaust gas flow rate or tar component concentration occurs. Become. In particular, by controlling the cooling conditions of the gas precooling section 3 or the gas cooling section 4 based on the odor component concentration in the exhaust gas after passing through the gas precooling section 3, the exhaust gas cooling conditions can be adjusted early. And the odor component concentration can be reliably reduced.

  As the gas analyzer 5 shown in FIGS. 1, 2, and 6, a gas chromatograph, a gas chromatograph-mass spectrometer, or the like can be used. However, the above-described gas having high detection sensitivity of odor components and excellent continuous monitoring properties. As the analyzer 5, a laser ionization mass spectrometer is preferable, and a vacuum ultraviolet one-photon ionization mass spectrometer is more preferable.

In FIG. 7, the schematic diagram of the vacuum ultraviolet 1 photon ionization mass spectrometer 5 provided with the vacuum ultraviolet laser light source and the mass analyzer is shown.
As shown in FIG. 7, the vacuum ultraviolet laser light source includes a laser generator 50 and a vacuum ultraviolet light generator 52. In the vacuum ultraviolet light generation section 52, ultraviolet light 54 (ultraviolet laser light) generated by the laser generation section 50 (oscillation) (Nd: YAG laser triple wave (355 nm) in a gas cell 52a filled with Xe gas at an appropriate pressure. )) Is introduced into the vacuum ultraviolet light generator 52 via the mirror 51, and the ultraviolet light 54 is converted again into a third harmonic wave at the focal point in the vacuum ultraviolet light generator 52, thereby obtaining vacuum ultraviolet light (118 nm wavelength). (Vacuum ultraviolet laser light) 55 is generated (oscillated). The larger the number of laser repetitions, the better. However, this number of repetitions depends on the number of repetitions of the ultraviolet laser that is the source of the generation of the vacuum ultraviolet light 55. The wavelength of the vacuum ultraviolet light 55 generated from the vacuum ultraviolet light generation unit 52 is not limited to 118 nm. For example, the range of 100 nm to 150 nm can be used as the wavelength of vacuum ultraviolet light.

Here, when the ultraviolet light 54 that is the third harmonic of the Nd: YAG laser is directly incident on the ionization chamber 53, there is a high possibility that the molecule to be measured is decomposed. As a countermeasure, the difference in refractive index between the ultraviolet light 54 and the vacuum ultraviolet light 55 is utilized, and the ultraviolet light 54 is separated by adjusting the angle and position of the lens made of MgF ₂ that is a condenser lens. It is effective to design the optical system so that only the vacuum ultraviolet light 55 enters the ionization chamber 53.

The relationship between the photon energy ε and the wavelength λ of the ultraviolet laser light is expressed by the following equation (1).
ε = hc / λ (1)
However, h is Planck's constant and c is the speed of light.

  Since all the molecules having an ionization potential lower than the photon energy of the vacuum ultraviolet laser represented by the formula (1) are ionized all at once, they can be detected by mass spectrometry. As described above, in this embodiment, since the ionization potential of the vacuum ultraviolet laser beam is 10.5 eV, molecules such as nitrogen, oxygen, argon, etc. that are present in the atmosphere at a constant rate are not ionized regardless of odor. Therefore, molecules that do not contribute to odor even if the amount of molecules present is large are not detected.

  The ionization unit 53 and the time-of-flight mass analysis unit 58 are changed from atmospheric pressure to a vacuum state using, for example, a rotary pump and two turbo molecular pumps (manufactured by Pfeiffer Vacuum).

  The gas introduction unit 56 is connected to a first sorting pipe 47 or a second sorting pipe 48 branched from the connection pipe 7 or the exhaust pipe 8. The gas introduction unit 56 has a pump (not shown) that introduces the exhaust gas flowing in from the connection pipe 7 or the exhaust pipe 8 into the ionization chamber 53. Even when a small pump with a pumping speed of about 70 L / s is used as this pump, since the outside air is introduced into the ionization chamber 53 without being disturbed and measured, the gas introduction unit 56 has a dust filter (not shown). Have From the collected exhaust gas to be measured, dust of 7 μm or more is removed with a dust filter, and the exhaust gas to be measured that has passed through the dust filter is discharged from the exhaust gas outlet (minimal pinhole) into an ionization chamber that is a vacuum chamber. 53 is introduced continuously.

  The gas introduction unit 56 is a direct injection type gas in which the electrode itself also serves as the ejection port, and is introduced into the time-of-flight mass analysis unit 58 (mass analyzer) coaxially with the ejection port without bending the ionized molecules. This is the introduction part.

  The exhaust gas to be measured introduced into the ionization chamber 53 from the ejection port of the gas introduction unit 56 is photoionized at the ionization point by being irradiated with the vacuum ultraviolet light 55 and becomes the ion I. The ions I enter the time-of-flight mass analyzer 58 while accelerating through the ion inlet of the ion inlet electrode 57 due to a potential difference between the gas inlet 56 and the ion inlet electrode 57.

  The mass spectrometer includes a time-of-flight mass analyzer 58 having an MCP (multi-channel plate) detector 58a and a reflectron 58b.

  The ion I (ionized molecule) is turned back by the reflectron 58b and detected by the MCP detector 58a, and the signal of the ion I is output as a current amount. A mass spectrum (mass number) is obtained by accelerating the ionized measurement target gas in a pulse manner and detecting a time difference until it is detected by the MCP detector 58a. In other words, if the amount of charge received by the ions I is constant, a mass spectrum is obtained by utilizing the fact that the larger the mass-to-charge ratio, the slower the flight time.

By providing the gas analyzer 5 shown in FIG. 7, the exhaust gas treatment devices 1, 21, 41 can be continuously operated, and the gas precooling unit 3 and the gas cooling unit can be measured by accurately measuring the odor component concentration. 4 cooling conditions can be appropriately controlled.

  Hereinafter, the present invention will be described in more detail with reference to examples.

Example 1
The exhaust gas treatment apparatus 1 shown in FIG. 1 is provided in a route for guiding and discharging the exhaust gas of the tar utilization facility. The temperature in the exhaust gas before being introduced into the gas precooling section 3 was 55 ° C. The exhaust gas that passed through the gas precooling section 3 in FIG. 1 was introduced into the gas cooling section 4 through the connecting pipe 7. As a cooling method of the gas precooling unit 3 and the gas cooling unit 4, a well-known radiator type in which a cooling solvent was passed through a coiled pipe was used.

  Here, the concentration of the odor component in the exhaust gas before being introduced into the gas precooling section 3 is phenol: 2 ppm, naphthalene: 25 ppm, 2-methylnaphthalene: 12 ppm, indane: 3 ppm, indene under the condition of the exhaust gas temperature of 55 ° C. : 3.5 ppm. The exhaust gas sampled from the preparatory pipe on the outlet side of the gas cooling unit 4 was analyzed by the gas analyzer 5 and the odor component concentration was measured. The exhaust gas temperature at the discharge port 3d of the gas preliminary cooling unit 3 was 8 to 10 ° C., and the odor component in the exhaust gas when the exhaust gas temperature of the gas cooling unit 4 was changed was measured with the gas analyzer 5. The gas analyzer 5 used a laser ionization mass spectrometer (vacuum ultraviolet one-photon ionization mass spectrometer) to generate 118 nm vacuum ultraviolet laser light and irradiate the sample gas. The measurement results are shown in FIG. As is apparent from FIG. 8, it was found that the concentration of each odor component can be made to be the olfactory threshold or less if the temperature of the gas cooling unit 4 is made 5 ° C. or less.

(Example 2)
Exhaust gas containing phenol: 8 ppm, naphthalene: 35 ppm, 2-methylnaphthalene: 18 ppm, indane: 6 ppm, and indene: 7 ppm was continuously treated by the exhaust gas treatment apparatus 1 shown in FIG. Similarly to Example 1, the concentration of odor components contained in the exhaust gas after passing through the gas cooling unit 4 was measured by a laser ionization mass spectrometer. At this time, the exhaust gas temperature at each outlet of the gas preliminary cooling unit 3 and the gas cooling unit 4 was changed, and the time until the cooling pipe 4a was blocked was examined. Generation | occurrence | production of obstruction | occlusion was judged with the flowmeter provided in the middle of the cooling pipe 4a. The results are shown in Table 2.

  As shown in Table 2, test no. In 1-3 (this invention), the density | concentration of each odor component in the waste gas after passing the gas cooling part 4 was all less than the olfactory threshold value of Table 1.

On the other hand, test no. 4 to 6 are comparative examples.
Test No. In No. 4, the exhaust gas temperature at the outlet of the gas preliminary cooling unit 3 exceeded 10 ° C., and the preliminary removal of tar was insufficient, so that the cooling piping of the gas cooling unit 4 was blocked in a short time.
Test No. 5, because the exhaust gas cooling in the gas precooling unit 3 was insufficient, more tar components were introduced into the gas cooling unit 4 without being removed, so that the cooling pipe 4a was quickly blocked. Removal of odorous components was also incomplete.
Test No. No. 6, since the exhaust gas cooling in the gas cooling unit 4 was insufficient, the concentration of some odor components in the exhaust gas after passing through the gas cooling unit 4 exceeded the olfactory threshold.

(Example 3)
Exhaust gas containing phenol: 10 ppm, cresol: 10 ppm, naphthalene: 35 ppm, 2-methylnaphthalene: 25 ppm, indane: 7 ppm, and indene: 9 ppm was continuously treated by the exhaust gas treatment device 41 shown in FIG. At that time, the exhaust gas temperature at the outlet of the gas precooling unit 3 was about 10 ° C., and the exhaust gas temperature at the outlet of the gas cooling unit 4 was about 5 ° C. When the concentration of the odor component contained in the exhaust gas after passing through the gas cooling unit 4 was measured by a laser ionization mass spectrometer in the same manner as in Example 1, cresol: 100 ppb, 2-methylnaphthalene: 120 ppb, indene: about 70 ppb Was detected.

  Therefore, as described with reference to FIG. 6, the odor component concentration in the exhaust gas after passing through the gas precooling unit 3 is measured by a laser ionization mass spectrometer, and based on the measurement result, the cooling control unit 46 and the gas precooling unit 3 By changing the cooling conditions of the gas cooling unit 4, the feedback control is performed so that the exhaust gas temperature at the outlet of the gas preliminary cooling unit 3 is cooled to about 9 ° C and the exhaust gas temperature at the outlet of the gas cooling unit 4 is cooled to about 4 ° C. went. As a result, the concentrations of cresol, 2-methylnaphthalene and indene in the exhaust gas after passing through the gas cooling unit 4 were all less than 1 ppb, and fell below the odor threshold within 1 minute after the concentration abnormality was felt.

Example 4
In the exhaust gas treatment device 41 shown in FIG. 6, the odor component concentration after passing the exhaust gas discharged from the tar utilization facility through the gas precooling unit 3 was measured by the gas analyzer 5 and was found to be toluene: 12 ppm, xylene. : 12 ppm, phenol: 1.2 ppm, indene: 1.2 ppm, indane: 1.2 ppm, naphthalene: 4.8 ppm, methylnaphthalene: 4.8 ppm. The exhaust gas temperature at the outlet of the gas precooling section 3 at that time was 10 ° C.

Therefore, immediately after measuring the above concentration with the gas analyzer 5, the cooling conditions of the gas precooling section 3 were changed, and the exhaust gas temperature at the discharge port 3d of the gas precooling section 3 was lowered to 5 ° C. The concentrations decreased to 1.5 ppm, the concentrations of phenol, indene, and indane decreased to 0.5 ppm, and the concentrations of naphthalene and methylnaphthalene decreased to 0.5 ppm, respectively.
By carrying out such control, the above-mentioned feedback technology enables cooling without excess and deficiency, and the cooling pipe 4a is not blocked for 700 hours or more, and the exhaust gas after passing through the gas cooling section 4 The odor component concentration was below the odor threshold.

  DESCRIPTION OF SYMBOLS 1 ... Exhaust gas processing apparatus, 2 ... Exhaust gas flow path, 3, 23, 43 ... Gas precooling part, 3a, 23a, 33a ... Preliminary cooling pipe, 4 ... Gas cooling part, 4a ... Cooling pipe, 5 ... Gas analyzer, 46 ... Cooling control unit, 47 ... First sorting tube (sorting tube), 50 ... Laser generating unit (vacuum ultraviolet laser light source), 52 ... Vacuum ultraviolet light generating unit (vacuum ultraviolet laser light source), 53 ... Ionization chamber, 58. Time-of-flight mass spectrometer (mass analyzer).

Claims (9)

A gas precooling step of precooling exhaust gas containing a tar component to remove the tar component from the exhaust gas;
A gas cooling step of cooling the exhaust gas after the gas pre-cooling step and removing the tar component remaining in the exhaust gas,
An exhaust gas treatment method for a tar utilizing facility, characterized in that an exhaust gas temperature at the end of the gas precooling step is 5 ° C. or more and 10 ° C. or less, and an exhaust gas temperature at the end of the gas cooling step is 5 ° C. or less. In the tar component in the exhaust gas before the gas precooling step, in mass concentration,
Toluene: 100 ppm or less,
Xylene: 100 ppm or less,
Phenol: 10 ppm or less,
Inden: 10 ppm or less,
Indan: 10 ppm or less,
o-cresol, m-cresol, p-cresol: 2 ppm or less each,
Naphthalene: 40 ppm or less,
Methylnaphthalene: 40 ppm or less,
2. The exhaust gas treatment method for a tar utilizing facility according to claim 1, wherein one or more odor components are included. Fractionating the exhaust gas after the gas pre-cooling step and / or after the gas cooling step,
Measure the concentration of odorous components in the collected exhaust gas,
The tar utilization facility according to claim 1 or 2, wherein a cooling condition of the exhaust gas in the gas preliminary cooling step and / or the gas cooling step is controlled based on a concentration of the odor component of the exhaust gas. Exhaust gas treatment method. In the gas precooling step, the inner diameter of the precooling pipe for flowing the exhaust gas is 50 mm or more,
In the gas cooling step, the inner diameter of the cooling pipe through which the exhaust gas flows is 25 mm or more,
The exhaust gas treatment method for a tar utilizing facility according to any one of claims 1 to 3, wherein a ratio of an inner diameter of the preliminary cooling pipe to an inner diameter of the cooling pipe is 2: 1 or more. A gas analysis method for measuring the concentration of odorous components in the exhaust gas,
The exhaust gas collected in the ionization chamber evacuated is guided, the exhaust gas is irradiated with laser light in the ionization chamber to ionize the odor component, and the ionized odor component is guided to a mass analyzer to determine its mass. 5. The exhaust gas treatment method for a tar utilization facility according to claim 3 or 4, wherein the measurement method is laser ionization mass spectrometry. An exhaust gas flow path;
A gas precooling section that is provided in the middle of the exhaust gas flow path and precools the exhaust gas containing the tar component to remove the tar component from the exhaust gas;
A gas cooling unit that is provided downstream of the gas preliminary cooling unit of the exhaust gas flow path, cools the exhaust gas, and removes the tar component remaining in the exhaust gas from the exhaust gas,
The gas precooling section can cool the temperature of the exhaust gas at the outlet to 5 ° C. or less,
The gas cooling unit is an exhaust gas treatment device for a tar utilizing facility capable of cooling the temperature of the exhaust gas at the outlet to 5 ° C to 10 ° C. A sorting pipe branched from the gas flow path on the exit side of the gas precooling section;
A gas analyzer that is connected to the sorting pipe and measures the concentration of an odorous component contained in the tar component of the exhaust gas separated from the exhaust gas flow path via the sorting pipe;
A cooling control unit that controls cooling conditions of the gas cooling unit and / or the gas preliminary cooling unit based on the concentration of the odor component;
The exhaust gas treatment apparatus for a tar utilization facility according to claim 6. In the gas precooling section, the precooling pipe forming the exhaust gas flow path has an inner diameter of 50 mm or more,
In the gas cooling part, the inner diameter of the cooling pipe forming the exhaust gas flow path is 25 mm or more,
The exhaust gas treatment apparatus for a tar utilizing facility according to claim 6 or 7, wherein a ratio of an inner diameter of the preliminary cooling pipe to an inner diameter of the cooling pipe is 2: 1 or more.   The gas analyzer includes a vacuum ultraviolet laser light source, an ionization chamber that ionizes the odor component by irradiating the fractionated exhaust gas with laser light oscillated from the vacuum ultraviolet laser light source, and a mass of the odor component. The exhaust gas treatment apparatus for a tar utilizing facility according to claim 7 or 8, wherein the apparatus is a laser ionization mass spectrometer equipped with a mass analyzer for measurement.

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