JP3617622B2 - Gas analyzer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gas analyzer for the dust-containing exhaust gas generated in an incinerator or melt furnace was collected at the sampling tube analysis.
[0002]
[Prior art]
Conventionally, as a gas analyzer that analyzes exhaust gas generated in, for example, a waste incinerator, the purpose is to monitor the concentration of O ₂ , NO _X , SO _X , HCl, CO, etc. in the exhaust gas discharged from the chimney. It is known that the exhaust gas after dust removal is sampled on the dust collector outlet side.
[0003]
However, when sampling is performed at the outlet side of the dust collector in this way, only data that is delayed by several tens of seconds can be obtained from the data in the incinerator or at the incinerator outlet, and air at the time of water spraying or alkaline chemical blowing is mixed in. However, since the exhaust gas concentration is different from that in the furnace, there is a problem that the exhaust gas analysis data is insufficient for use in combustion control in the combustion furnace.
[0004]
In order to deal with such problems, a sampling probe for sampling the exhaust gas is attached to the furnace wall to analyze the gas around the furnace wall, or the periphery is covered with a water cooling jacket There have been proposed ones in which a water-cooled probe is inserted into a high-temperature part in a furnace to analyze the gas in the high-temperature part.
[0005]
In any of these cases, the structure shown in FIG. 3 is adopted in the conventional gas analyzer. That is, the tip of a steel sampling tube 50 having a hole 50a at the tip is protruded from the furnace wall 51 into the furnace, and the exhaust gas introduced from the hole 50a is guided to a cylindrical filter paper 53 with a heater 52, After the dust in the exhaust gas is collected by the cylindrical filter paper 53, the exhaust gas after the dust collection is guided to the analyzer 55 via the drain bin 54. Here, the heater 52 is provided so that moisture contained in the exhaust gas does not adhere to the surface of the cylindrical filter paper 53. Note that a reference numeral 56 in FIG. 3 denotes a glass holder for holding the cylindrical filter paper 53.
[0006]
[Problems to be solved by the invention]
However, in the case of sampling the gas around the furnace wall, the average gas in the furnace is not sampled. Therefore, when the analysis data of this suction gas is used for combustion control of the incinerator, the accuracy is high. There is a problem that control cannot be performed. Further, in the case where a water-cooled probe is inserted in a high-temperature part, there is a risk that combustion of combustible gas may be hindered by the influence of the water-cooled probe, particularly in the case of a small furnace. In any case, as shown in FIG. 3, since the dust is removed by the cylindrical filter paper 53, the cylindrical filter paper 53 is clogged in a short time and sampling becomes impossible. For this reason, it is necessary to periodically replace the cylindrical filter paper 53 (for example, every several tens of minutes to several hours), which is not practical for continuous analysis of exhaust gas.
[0007]
The present invention has been made in view of such problems, it is an object that you provide a gas analyzer capable of continuously sampling the exhaust gas outlet of the incinerator.
[0008]
[Means for solving the problems and actions / effects]
In order to achieve the above object, a gas analyzer according to the first invention comprises:
A gas analyzer that collects and analyzes dust-containing exhaust gas generated in an incinerator or the like in a sampling tube formed by a porous filter whose inner end portion has heat resistance,
The sampling tube is arranged so that the porous filter portion protrudes into the furnace, and two sampling tubes are provided in parallel, and dust adhering to the surface of each porous filter is blown into the compressed fluid. And a compressed fluid blowing means for alternately removing dust from each porous filter.
[0009]
According to the present invention, since the furnace inner end of the sampling tube is formed of a heat-resistant porous filter, the sampling tube can be inserted into the high temperature portion in the furnace, and the sampling tube can be damaged. Without introducing the exhaust gas in the high temperature portion, it can be used for gas analysis, whereby the gas analysis can be performed with high accuracy. In addition, since a porous filter is used, when dust adheres to this filter, the dust can be instantaneously removed by backwashing with a compressed fluid, and only continuous analysis of exhaust gas is possible. In addition, periodic replacement work as in the case of using a cylindrical filter paper is not necessary. Further, according to the present invention, two sampling tubes are provided in parallel, and dust removal of each porous filter is alternately performed, so that the porous filter can be reliably prevented from being clogged. The other sampling tube can be used during backwashing of one sampling tube, and the continuous analysis of exhaust gas and the continuous removal of dust can be reliably performed.
[0010]
According to a second invention, in the first invention, the temperature of the dust-containing exhaust gas is in the range of 150 ° C to 1200 ° C. By using a heat-resistant porous filter in this way, high-temperature gas analysis can be performed without using a cooling jacket.
[0011]
In a third aspect of the present invention, the porous filter according to the first aspect or the second aspect is made of ceramic or stainless steel.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Next, a specific embodiment of the gas analyzer according to the present invention will be described with reference to the drawings.
[0016]
FIG. 1 shows a configuration diagram of a gas analyzer according to an embodiment of the present invention.
[0017]
The gas analyzer 1 of the present embodiment is configured such that a unit including a first sampling pipe (probe) 3 and a unit including a second sampling pipe 4 are arranged in parallel on the furnace wall 2 of the incinerator. Has been. Each sampling tube 3, 4 has a porous tube (porous filter) 5, 6 made of ceramic (eg, cordierite) at the tip, and this porous tube 5, 6 portion enters the furnace. It is arranged to protrude. Here, the heat resistance temperature of the porous tubes 5 and 6 is about 1300 ° C. The exhaust gas temperature is 400 ° C to 1200 ° C.
[0018]
Extraction pipes 7 and 8 are connected to the base ends of the sampling pipes 3 and 4, respectively. The extraction pipes 7 and 8 are joined to one merged extraction pipe 9, and the drain bins are connected through the merged extraction pipe 9. 10 is connected. An analyzer 11 is connected to the drain bin 10. Each of the extraction pipes 7 and 8 is provided with a first exhaust gas solenoid valve 12 and a second exhaust gas solenoid valve 13 at positions slightly in front of the junction with the merge extraction pipe 9.
[0019]
Further, each of the extraction pipes 7 and 8 is branched into a first compressed fluid introduction pipe 14 and a second compressed fluid introduction pipe 15 respectively before the position where the exhaust gas solenoid valves 12 and 13 are disposed. Each compressed fluid introduction pipe 14, 15 is connected to a compressed fluid source 16. A first compressed fluid solenoid valve 17 and a second compressed fluid solenoid valve 18 are inserted in the middle of the compressed fluid introduction pipes 14 and 15, respectively. The compressed fluid introduction pipes 14 and 15, the compressed fluid source 16, the compressed fluid electromagnetic valves 17 and 18, and the like in the present embodiment correspond to the compressed fluid blowing means in the present invention.
[0020]
In such a configuration, during normal exhaust gas analysis, the exhaust gas solenoid valves 12 and 13 are opened, the compressed fluid solenoid valves 17 and 18 are closed, and the porous materials in both sampling tubes 3 and 4 are closed. The exhaust gas is sampled from the pipes 5 and 6. At this time, since the dust contained in the exhaust gas is collected by the porous tubes 5 and 6, the exhaust gas after the dust collection passes through the extraction tubes 7 and 8, the combined extraction tube 9 and the drain bin 10. Then, it is guided to the analyzer 11. In this way, the analyzer 11 analyzes the CO concentration, NO _X concentration, and the like in the exhaust gas.
[0021]
Then, the first exhaust gas solenoid valve 12 is closed after a certain time, and then the first compressed fluid solenoid valve 17 is opened. As a result, the compressed fluid (air or nitrogen) is instantaneously blown from the compressed fluid source 16 through the compressed fluid introduction tube 14 and the extraction tube 7 into the porous tube 5, and the dust attached to the porous tube 5 is removed. Be dropped. After the dust is discharged, the first compressed fluid electromagnetic valve 17 is closed and the first exhaust gas electromagnetic valve 12 is opened.
[0022]
When a certain time has passed, the second exhaust gas solenoid valve 13 is closed and then the second compressed fluid solenoid valve 18 is opened. As a result, the compressed fluid is instantaneously blown from the compressed fluid source 16 through the compressed fluid introduction tube 15 and the extraction tube 8 into the porous tube 6, and the dust attached to the porous tube 6 is removed. After the dust is discharged, the second compressed fluid electromagnetic valve 18 is closed and the second exhaust gas electromagnetic valve 13 is opened. In this manner, by alternately discharging dust from the porous tubes 5 and 6, exhaust gas can be continuously analyzed, and dust can be continuously discharged.
[0023]
FIG. 2 shows a system diagram when the gas analyzer 1 according to the present embodiment is applied to a combustion control device for an incinerator.
[0024]
In the incinerator 20 shown in FIG. 2, a hopper 22 into which garbage 21 as a combusted material is charged, a stalker 23 for burning the garbage 21 charged from the hopper 22, and an upper side of the stalker 23. A combustion chamber 25 defined by the furnace wall 24, a primary combustion air supply device 26 for supplying primary combustion air into the combustion chamber 25 through the stoker 23, and an ash discharge port 27 for taking out incinerated ash after combustion are provided. It has been.
[0025]
The combustion chamber 25 is divided into a primary combustion zone 25a above the stoker 23, a reburning zone 25b above the primary combustion zone 25a, and a secondary combustion zone 25c above the reburning zone 25b. A natural gas / recirculation gas supply pipe 28 for supplying natural gas and recirculation gas is connected to the lower furnace wall 24 of the reburning zone 25b, and a secondary wall is connected to the lower furnace wall 24 of the secondary combustion zone 25c. A secondary combustion air supply pipe 29 for supplying combustion air is connected. Further, a recirculation gas supply pipe 34 and a natural gas supply pipe 35 are connected to the natural gas / recirculation gas supply pipe 28, respectively. Here, dampers 30, 36, and 31 for supply amount control are interposed in the secondary combustion air supply pipe 29, the recirculation gas supply pipe 34, and the natural gas supply pipe 35, respectively.
[0026]
In the present embodiment, the porous tubes 5 and 6 are arranged above the secondary combustion zone 25c, and data such as CO concentration in the exhaust gas analyzed by the analyzer 11 is the controller (gas supply control means) 32. To be input. Thus, the controller 32 calculates the optimum secondary air supply amount based on the input data from the analyzer 11 and outputs an open / close control signal to the damper 30 to control the opening degree of the damper 30. The porous tubes 5 and 6 are arranged in the reburning zone 25b, and data such as O ₂ concentration and NO _X concentration in the exhaust gas analyzed by the analyzer 37 having the same configuration as the analyzer 11 is stored in the controller ( Gas supply control means) 38. Thus, the controller 38 calculates the optimum natural gas supply amount based on the input data from the analyzer 37 and outputs an open / close control signal to the damper 31 to control the opening degree of the damper 31.
[0027]
In this way, the combustion gas in the primary combustion zone 25a under the combustion chamber 25 is mixed to make the temperature distribution uniform and maintain a relatively low oxygen atmosphere. By supplying the gas, a completely reducing atmosphere is formed in the reburning zone 25b. Further, hydrocarbon gas, CO gas, and the like generated in the combustion gas by the primary combustion are completely burned by the secondary combustion air in the secondary combustion zone 25c.
[0028]
According to the present embodiment, the exhaust gas state in the furnace can be analyzed in real time, and the supply amounts of secondary air, natural gas, and recirculation gas can be controlled based on this analysis data. High-precision control can be realized.
[0029]
In the present embodiment, the control of the amount of recirculation gas, the amount of natural gas and the amount of secondary air supplied into the furnace has been described. However, the amount of primary combustion air can also be controlled. Further, the supply amount of any of these primary combustion air amount, secondary combustion air amount, natural gas amount, and recirculation gas amount may be controlled.
[0030]
In the present embodiment, the porous tubes 5 and 6 provided in the upper part of the secondary combustion zone 25c are provided in the middle of the exhaust gas passage 33 connected to the secondary combustion zone 25c, as indicated by a broken line in FIG. Anyway.
[0031]
In the present embodiment, the exhaust gas solenoid valves 12 and 13 and the compressed fluid solenoid valves 17 and 18 have been described as separate solenoid valves. However, the exhaust gas solenoid valves 12 and 13 and the compressed fluid solenoid valves 17 and 18 Each may be a three-way switching valve.
[0032]
In the present embodiment, the porous tube is described as being made of ceramic, but may be made of stainless steel.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a gas analyzer according to an embodiment of the present invention.
FIG. 2 is a system diagram when the gas analyzer according to the present embodiment is applied to a combustion control device of an incinerator.
FIG. 3 is a configuration diagram of a conventional gas analyzer.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Gas analyzer 2 Furnace wall 3, 4 Sampling pipes 5, 6 Porous pipes 7, 8 Extraction pipe 9 Combined extraction pipe 10 Drain bin 11, 37 Analyzer 12, 13 Exhaust gas solenoid valve 14, 15 Compressed fluid introduction pipe 16 Compressed fluid Sources 17, 18 Compressed fluid solenoid valve 20 Incinerator 23 Stoker 25 Combustion chamber 26 Primary combustion air supply device 28 Natural gas / recirculation gas supply pipe 29 Secondary combustion air supply pipe 30, 31, 36 Damper 32, 38 Controller 33 Exhaust gas Passage 34 Recirculation gas supply pipe 35 Natural gas supply pipe

Claims (3)

A gas analyzer for collecting and analyzing dust-containing exhaust gas generated in an incinerator or the like in a sampling tube formed by a porous filter whose inner end portion has heat resistance,
The sampling tube is arranged so that the porous filter portion protrudes into the furnace, and two sampling tubes are provided in parallel, and dust adhering to the surface of each porous filter is blown into the compressed fluid. The gas analyzer is characterized in that it is provided with a compressed fluid blowing means that periodically removes dust from each porous filter and alternately removes dust from each porous filter. The gas analyzer according to claim 1, wherein the temperature of the dust-containing gas is in a range of 150C to 1200C. The gas analyzer according to claim 1 or 2, wherein the porous filter is made of ceramic or stainless steel.

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