JP2006258462A - Gas analyzer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas analyzer extremely simple in its constitution and constituted so as to prevent an exhaust gas after analysis from being discharged into the atmosphere. <P>SOLUTION: The gas analyzer is equipped with a sampling pipe 8 for collecting the exhaust gas in an exhaust gas passage 2, a stagnation chamber (first and second space parts 4 and 6) for stagnating the exhaust gas collected by the sampling pipe 8, the zirconia type oxygen analyzer probe 11 arranged in the stagnation chamber to analyze the concentration of oxygen in the exhaust gas, the reflux flow channel arranged so as to allow the stagnation chamber to communicate with the inside of the exhaust gas passage 2 to reflux the exhaust gas, after analyzed by the zirconia type oxygen analyzer probe 11, into the exhaust gas passage 2 and an ejector for ejecting compressed air into the reflux flow channel in order to introduce the exhaust gas into the stagnation chamber from the exhaust gas passage 2. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a gas analyzer for collecting and analyzing exhaust gas in a furnace or an exhaust gas passage with a sampling pipe.

Conventionally, incinerators, etc., analyze the concentration of O ₂ , CO, NOx, etc. in the exhaust gas with a gas analyzer to prevent the emission of harmful components into the environment, and burn based on this analysis data Control is to be done.

  By the way, when performing combustion control using this type of gas analyzer, if the exhaust gas after dust removal at the dust collector outlet side is sampled, there is a time lag with respect to the exhaust gas data in the furnace or at the furnace outlet. Also, since the exhaust gas concentration is different from that in the furnace, there is a problem that the exhaust gas data is insufficient for use for combustion control.

  Therefore, in order to perform combustion control with high accuracy, in Patent Document 1, a ceramic or stainless steel porous filter is attached to the tip of a sampling probe for sampling exhaust gas, and this porous filter is attached to an incinerator. There has been proposed a method in which a dust-containing exhaust gas generated in a furnace is introduced into an analyzer through a porous filter so as to protrude into the furnace. Similar devices are also proposed in Patent Documents 2 to 4.

JP 2002-139409 A JP-A-6-81027 Japanese Patent Laid-Open No. 7-5083 JP 2000-227389 A

  However, all of the conventional gas analyzers are configured to discharge the analyzed gas into the atmosphere after conducting exhaust gas analysis in the furnace or exhaust gas passage to the analyzer and analyzing the CO concentration and the like. Therefore, there is a problem that it is not preferable for environmental conservation. In addition, when an analyzer that requires a dehumidifier, such as a magnetic oxygen analyzer that uses paramagnetism, is used as this type of analyzer, it is responsive to highly accurate combustion control. In addition, there are problems in that the apparatus configuration is complicated and large because it is necessary to perform a drain treatment after dehumidifying the exhaust gas.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a gas analyzer that has an extremely simple device configuration and that does not release exhaust gas after analysis into the atmosphere. It is what.

In order to achieve the above object, a gas analyzer according to the present invention comprises:
In a gas analyzer that collects and analyzes exhaust gas in the furnace or exhaust gas passage with a sampling pipe,
(A) a retention chamber for retaining the exhaust gas collected by the sampling tube;
(B) an oxygen analyzer probe disposed in the residence chamber for analyzing the oxygen concentration in the exhaust gas;
(C) a reflux path that is arranged so as to communicate between the staying chamber and the furnace or the exhaust gas passage, and for refluxing the exhaust gas after being analyzed by the oxygen analyzer probe into the furnace or the exhaust gas passage;
(D) An ejector for injecting pressurized air into the recirculation path in order to introduce exhaust gas into the stay chamber from the furnace or the exhaust gas passage (first invention).

  In the present invention, it is preferable that a compressed air blowing pipe for blowing compressed air into the sampling pipe is provided (second invention).

  Moreover, it is preferable that the oxygen analyzer probe is a zirconia oxygen analyzer probe that is directly inserted into the residence chamber and attached (third invention).

  Furthermore, the tip of the sampling tube protruding into the furnace or the exhaust gas passage may be formed of a heat-resistant porous filter (fourth invention).

  According to the present invention, the retention chamber for retaining the collected exhaust gas and the inside of the furnace or the exhaust gas passage are communicated with each other through the reflux path, and pressurized air is injected from the ejector into the reflux path. Therefore, the ejector functions as an exhaust gas suction device and the exhaust gas is sucked into the retention chamber, and the analyzed exhaust gas is discharged into the furnace or the exhaust gas passage together with the pressurized air injected from the ejector. Therefore, the exhaust gas after analysis is not released into the atmosphere, and environmental pollution can be prevented in advance. In addition, since the oxygen analyzer probe is arranged in the residence chamber, the apparatus configuration can be extremely simplified, and the exhaust gas can be continuously analyzed to improve the control responsiveness.

  If the structure of the said 2nd invention is employ | adopted, the dust adhering to the outer surface of a sampling pipe | tube can be reliably wiped off by the compressed air injected from a compressed air blowing pipe | tube.

  In addition, when a zirconia oxygen analyzer probe is used as in the third aspect of the invention, the responsiveness is fast, and no additional device such as a dehumidifier is required, and the device configuration can be further simplified.

  In addition, according to the configuration of the fourth invention, the sampling tube can be inserted into the high temperature portion in the furnace, and the exhaust gas in the high temperature portion is introduced without damaging the sampling tube to perform gas analysis with high accuracy. be able to.

  Next, specific embodiments of the gas analyzer according to the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view of a gas analyzer according to an embodiment of the present invention. FIG. 2 is a partial cross-sectional view of FIG. 1A (a) and FIG. B sectional view (b) is shown.

  The present embodiment is applied to an example in which the gas analyzer 1 is installed and used on a passage wall 3 of an exhaust gas passage 2 at a boiler outlet of a pyrolysis gasification melting plant (not shown).

  The gas analyzer 1 is fixed to the passage wall 3 of the exhaust gas passage 2 and has a first casing 5 having a first space portion 4 therein, and is flange-coupled to the rear end portion of the first casing 5 so as to be second inside. A second casing 7 having a space 6 and a cylindrical sampling tube (probe) 8 disposed on the tip side of the first casing 5 so as to penetrate the passage wall 3 are provided. Here, the sampling pipe 8 is constituted by an exhaust gas pipe 9 as an attachment metal fixed to the first casing 5 and a porous filter 10 fixed to the tip of the exhaust gas pipe 9 by flange connection. The porous filter 10 is made of ceramic or stainless steel in consideration of the exhaust gas temperature (150 to 1200 ° C.). Further, the exhaust gas pipe 9 is made of stainless steel.

  The first space portion 4 and the second space portion 6 communicate with each other so as to have substantially the same diameter, and the space portions 4 and 6 form a retention chamber in which exhaust gas is retained. An oxygen concentration detector 12 having a zirconia oxygen analyzer probe 11 at the distal end is inserted and fixed in the stay chamber (spaces 4 and 6) from the proximal end side of the second casing 7. This zirconia-type oxygen concentration detector 12 is formed between an inner electrode and an outer electrode according to a difference in oxygen concentration between the exhaust gas and the air in the zirconia element when the outer surface side of the tubular zirconia element is exhausted. Electric power is generated, and the oxygen concentration in the exhaust gas is detected using the electromotive force as a detection signal.

  An exhaust gas extraction pipe 13 is fixed to the rear end of the second casing 7 so as to be orthogonal to the axis of the second casing 7, and the exhaust gas extraction pipe 13 communicates with the exhaust gas extraction pipe 13 at the tip of the exhaust gas extraction pipe 13. Thus, the exhaust gas recirculation pipe 14 is attached in parallel with the axis of the second casing 7. The tip of the exhaust gas recirculation pipe 14 is fixed to the passage wall 3 of the exhaust gas passage 2. Thus, the second space 6 in the second casing 7 communicates with the exhaust gas passage 2 via the exhaust gas extraction pipe 13 and the exhaust gas recirculation pipe 14. Note that the exhaust gas extraction pipe 13 and the exhaust gas recirculation pipe 14 in the present embodiment correspond to the recirculation path in the present invention.

  An ejector 15 is provided at a connection portion between the exhaust gas extraction pipe 13 and the exhaust gas recirculation pipe 14. In this ejector 15, compressed air is injected into the exhaust gas recirculation pipe 14 from the injection nozzle, and this exhaust power causes the exhaust gas in the exhaust gas extraction pipe 13 to be injected into the exhaust gas recirculation pipe 14 while accompanying suction (ejector action). ). In addition, the diameter of the exhaust gas recirculation pipe 14 is expanded at the central portion, and the distal end portion (exhaust gas passage 2 side) is larger in diameter than the base end portion (ejector 15 installation side).

  Further, an exhaust gas detection pipe 16 is attached to a rear end portion of the second casing 7 at a position facing the exhaust gas extraction pipe 13, and a compound meter (micro-pressure gauge) 17 is provided at the tip of the exhaust gas detection pipe 16. It is attached. Thus, the exhaust gas pressure in the staying chamber (second space portion 6) is measured by the coupled meter 17.

  The first space 4, the second space 6, the exhaust gas extraction pipe 13, the exhaust gas recirculation pipe 14 and the exhaust gas detection pipe 16 are covered with a heat insulating material 18, and the second space 6, the exhaust gas extraction pipe 13, In the exhaust gas recirculation pipe 14 and the exhaust gas detection pipe 16, a tape heater 19 is installed under the heat insulating material 18. The tape heater 19 serves to prevent low-temperature corrosion of hardware by maintaining 200 ° C. when the surface temperature of the second casing 7, the exhaust gas extraction pipe 13, or the like is 200 ° C. or lower.

  In addition, a compressed air blowing pipe 20 for supplying compressed air is provided in the porous filter 10 in order to remove dust attached to the outer surface of the porous filter 10. The compressed air blowing pipe 20 is attached so as to pass through the heat insulating material 18 disposed in the first casing 5 and to be inserted into the exhaust gas pipe 9 from the upper surface of the exhaust gas pipe 9. Includes an electromagnetic valve 21 that is opened and closed by a pulse voltage. When the pressure difference between the exhaust gas pressure in the residence chamber detected by the coupled meter 17 and the exhaust gas pressure in the exhaust gas passage 2 detected by a pressure gauge (not shown) reaches a certain set value, the solenoid valve 21 Then, it is determined that dust has adhered to the outer surface of the porous filter 10, and the opening operation is performed based on a pulse signal from a controller (not shown). As a result, compressed air is supplied from the air source into the porous filter 10 through the compressed air blowing tube 20, and dust attached to the outer surface of the porous filter 10 is removed.

  In the gas analyzer 1 of the present embodiment, compressed air (pressurized air) is injected into the exhaust gas recirculation pipe 14 from the injection nozzle of the ejector 15, so that the retention chamber (first space portion 4, second space portion). 6) The inside becomes negative pressure, and as a result, the exhaust gas in the exhaust gas passage 2 is sucked into the staying chamber through the porous filter 10 and the exhaust gas pipe 9. In this residence chamber, the oxygen concentration of the exhaust gas removed by the porous filter 10 is analyzed by an oxygen concentration detector 12 having a zirconia oxygen analyzer probe 11, and the analyzed exhaust gas is injected from the ejector 15. The compressed air is discharged into the exhaust gas passage 2 through the exhaust gas recirculation pipe 14. Further, when the differential pressure between the exhaust gas pressure in the exhaust gas passage 2 and the exhaust gas pressure in the staying chamber detected by the compound meter 17 exceeds a set value, a pulse voltage is applied to the electromagnetic valve 21 of the compressed air blowing pipe 20. By being applied and opened, the dust attached to the outer surface of the porous filter 10 is removed.

  Thus, according to the gas analyzer 1 of the present embodiment, the exhaust gas after being analyzed by the oxygen concentration detector 12 is configured to recirculate to the exhaust gas passage 2 without being released into the atmosphere. There is an effect that environmental pollution can be prevented. Moreover, the direct insertion type zirconia oxygen analyzer probe is used to analyze the exhaust gas, so that the configuration of the apparatus can be extremely simplified and the exhaust gas can be continuously analyzed. There is an advantage that control responsiveness can be improved.

  In the present embodiment, the gas analyzer 1 installed on the passage wall 3 of the exhaust gas passage 2 has been described. However, the gas analyzer 1 can also be installed on the furnace wall of the incinerator.

Sectional drawing of the gas analyzer which concerns on one Embodiment of this invention A sectional view (a) in FIG. 1 and a sectional view taken along line BB in FIG. 1 (b).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Gas analyzer 2 Exhaust gas passage 3 Passage wall 4 1st space part (residence chamber)
5 1st casing 6 2nd space part (residence chamber)
7 Second casing 8 Sampling pipe 9 Exhaust gas pipe 10 Porous filter 11 Zirconia type oxygen analyzer probe 12 Oxygen concentration detector 13 Exhaust gas extraction pipe (reflux path)
14 Exhaust gas recirculation pipe (circulation path)
15 Ejector 16 Exhaust gas detection pipe 17 Compound meter (micro pressure gauge)
18 Heat insulating material 19 Tape heater 20 Compressed air blowing pipe 21 Solenoid valve

Claims (4)

In a gas analyzer that collects and analyzes exhaust gas in the furnace or exhaust gas passage with a sampling pipe,
(A) a retention chamber for retaining the exhaust gas collected by the sampling tube;
(B) an oxygen analyzer probe disposed in the residence chamber for analyzing the oxygen concentration in the exhaust gas;
(C) a reflux path that is arranged so as to communicate between the staying chamber and the furnace or the exhaust gas passage, and for refluxing the exhaust gas after being analyzed by the oxygen analyzer probe into the furnace or the exhaust gas passage;
(D) A gas analyzer comprising: an ejector that injects pressurized air into the reflux path in order to introduce exhaust gas into the stay chamber from the furnace or the exhaust gas passage.   The gas analyzer according to claim 1, wherein a compressed air blowing tube for blowing compressed air into the sampling tube is provided.   The gas analyzer according to claim 1 or 2, wherein the oxygen analyzer probe is a zirconia oxygen analyzer probe that is directly inserted into the residence chamber.   The gas analyzer according to any one of claims 1 to 3, wherein a tip portion of the sampling tube that protrudes into the furnace or the exhaust gas passage is formed of a heat-resistant porous filter.

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