JPH10148604A - Device and method measuring for dew-point temperature - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dew-point temperature measuring device capable of feeding back to preventive measures against low-temperature corrosion, i.e., the control of operating temperatures of a furnace by performing dew-point temperature measurement in parallel with the component analysis of adhered solids under conditions that new solids are adhering all the time, and monitoring the conditions of a corrosive environment. SOLUTION: This device is placed in a flue 59 through which component gas containing solids discharged from a furnace 50 flows for measuring the dew-point of the above-mentioned combustion gas by condensation on the detection plate (condensation plane) of a detector 10. In this case, a bypass line 53 is provided for a part of the flue 59 of the furnace 50, and a filter 54 which collects and removes solid such as combustion ashes is provided in the bypass line 53. In addition, a vibrator 55 which vibrates the filter 54 to drop the collected solids is provided, and a dew-point instrument is provided just beneath the vibrator 55. The detector of the dew-point instrument is detachable, and the surface of its detection plate is arranged to be constantly vertical in respect to the direction of falling of the solids and is provided with projections and depressions. With ever new solids adhered to the condensation plate, a dew-point temperature is measured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for measuring the dew point of combustion exhaust gas from a refuse incinerator or the like that generates a large amount of combustion ash or solid matter, and more particularly to an apparatus and a method for measuring the dew point of combustion ash. TECHNICAL FIELD The present invention relates to a dew point measuring device and method for continuously performing acid dew point temperature measurement at a temperature.

[0002]

2. Description of the Related Art Exhaust gas from refuse incinerators is SOx
(Sulfur oxides), it contains a large amount of HC1 (hydrogen chloride), and when a waste heat recovery boiler is installed in a refuse incinerator, hydrochloric acid dew point corrosion occurs in the air heater, heat transfer tube, desuperheater, etc. of the boiler. The possibility is pointed out.

Recently, the problem effects of NH ₄ C1 where the leakage NH ₃ and HC1 generated by reacting the plant increased uncatalyzed denitration by blowing certain furnace urea while is performed. For this reason, a dew point meter is often used to measure the dew point temperature inside a refuse incinerator.

FIG. 8 is a schematic view showing a dew point meter according to the prior art, and FIG. 9 is an enlarged view of arrow C in FIG. 8 and 9
In the dew point meter shown in FIG. 1, the probe tube 1 of the dew point meter penetrates the flue wall 38 of the refuse incinerator (the right side in the drawing of the flue wall 38 is the inside of the flue), and a detector is provided at the tip of the probe tube 1. (Detector) 10 is attached. The detector 10 is provided with a detection plate 4 made of chemically stable borosilicate glass and having a diameter of about 25 mm.
Is provided with a platinum ring electrode 5 having a diameter of about 10 mm. The center of the platinum ring electrode 5 has Pt-Pt /
A thermocouple 6 made of Rh is provided. The probe tube 1 has a cooling air supply pipe 14 and an air discharge pipe 15.
Is connected to the cooling air supply pipe 14, and a thermocouple 16 for measuring gas temperature is provided near the detector 10.

In this dew point meter, when cooling air is supplied into the probe tube 1 through the cooling air supply pipe 14, the detection plate 4 is cooled and dew forms on the surface of the detection plate 4. Electric current starts to flow between the platinum ring electrode 5 and the thermocouple 6 due to dew condensation. In this state, when the supply of the cooling air is stopped, the temperature of the detection plate 4 rises, and the moisture condensed on the surface of the detection plate 4 evaporates, and a current flows between the platinum ring electrode 5 and the thermocouple 6. Disappears. The temperature at which the rate of change in the current flowing between the platinum ring electrode 5 and the thermocouple 6 due to the repetition of condensation and evaporation is zero, that is, the temperature when the condensation and evaporation are in an equilibrium state is called the dew point temperature. .

However, in general, dew condensation and evaporation often occur instantaneously, in which case dew condensation occurs on the surface of the detection plate 4 and the platinum annular electrode 5 and the thermocouple 6
And the electric current flowing between the platinum ring electrode 5 and the thermocouple 6 suddenly increases,
The temperature at that time is often defined as the dew point temperature. Therefore, in the dew point meter shown in FIGS. 8 and 9, cooling air is supplied into the probe tube 1 to cool the detection plate 4, and a current flows between the platinum ring electrode 5 and the thermocouple 6 due to dew condensation. If the temperature at which the flow starts is detected by the thermocouple 6, the dew point temperature at that time can be measured.

The problem of the conventional method is that a probe detector (detector) 10 made of chemically stable borosilicate glass, which is known as a representative of an insulator, is originally measured in a clean gas environment. Therefore, the surface is smooth and has a spherical structure to which combustion ash, chloride, and the like are not easily adhered. As a result, it was impossible to measure the dew point under the condition that the solid matter contained in the combustion exhaust gas adhered. In addition, since the diameter of the annular electrode that detects the rate of change of the interelectrode current, that is, the dew point, is as small as about 10 mm,
Depending on the shape and location of the dew condensation water, it is difficult to detect dew condensation, and there is a problem in reproducibility and reliability.

[0008]

When a waste heat boiler is installed in a refuse incinerator, solid matters such as combustion ash and various chlorides adhere to air heaters, heat transfer tubes, temperature reducers, etc., and the heat transfer performance is reduced. Air heater,
It is desirable to know the dew point temperature in a state where the deposits adhere to the heat transfer tubes, the temperature reducers, and the like.

[0009] The above prior art is based on combustion ash or chloride (MgC
1 _2, a CaCl _2, FeCl _2, impossible to measure the dew point temperature in the solids deposited under NaC1, etc.), structural considerations in the measurement under the above environment is not performed.

[0010] It is an object of the present invention to always carry out the dew point temperature and the component analysis of the deposited solid in parallel with the deposition of a new solid,
It is an object of the present invention to provide a dew-point temperature measurement system that monitors corrosion environment conditions and enables feedback to low-temperature corrosion prevention measures, that is, feedback to furnace operating temperature control.

[0011]

In order to achieve this object, a dew point temperature of the combustion gas is set in a flue through which a combustion gas containing solid matter discharged from a furnace flows, and the dew point of the combustion gas is condensed on a condensation surface of a detector. In the dew point temperature measuring device to be measured, a bypass line is provided in a part of the flue of the furnace, and a filter for collecting and removing solids such as combustion ash is installed in the bypass line, and a dew point meter is provided immediately below the filter. Is provided.

Next, a vibrator for dropping solids collected by the filter by vibrating the filter is provided. Due to the installation of the vibrator, the adhered solids continuously drop from the filter to the dew point meter disposed below the filter. The dew point of the detector of the dew point meter is always perpendicular to the falling direction of the solid matter, and the dew point temperature is measured while a new solid matter is always attached to the dew surface.

In a dew point meter having a detector attached to a probe tube, a surface of a detection plate of the detector,
That is, the condensed surface on which the solids fall is provided with irregularities, and the detector is detachably attached to the probe tube.

Further, a washing means for jetting washing water to wash the surface of the detection plate of the detector is provided, and the surface of the detection plate is washed at predetermined time intervals.

[0015] While continuously measuring the dew point temperature under the above-mentioned solid matter attachment, the probe (detector) is periodically checked.
The components are analyzed in parallel with the solids attached to the detector surface, and the corrosive environmental conditions are monitored in real time by acquiring information on the dew point temperature and the components of the solids attached to the solids.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic system diagram showing the configuration of a main part of a first embodiment of the present invention, and FIG. 2 is an enlarged schematic diagram showing the vicinity of a probe detector (detector). . In this embodiment, the heating furnace 50 and the heating furnace 5 in the refuse incinerator are used.
A chimney 52 that emits exhaust gas coming out of the atmosphere into the atmosphere;
The present invention is applied to a device including a flue 59 connecting a heating furnace 50 and a chimney 52 and an electric dust collector (EP) 51 interposed in the flue 59.

In the illustrated apparatus, a dew point temperature measuring device includes a bypass line 53 provided in a flue 59, a filter 54 provided at an intermediate portion of the bypass line 53 and capable of collecting combustion ash, and the filter 54 being vibrated. A vibrator 55 for dropping solid matter 56 such as combustion ash adhered thereto;
A dew point meter including a probe tube 1 disposed directly below the filter 54 with the axis line extending vertically and a detector 10 mounted on the probe tube 1, and a temperature reading device 35 connected to the detector 10. And a cooling air control unit 2 (not shown) connected to the probe tube 1 and supplying cooling air.
And the probe tube 1 is periodically extracted and the detector 1
And an ash analyzer 58 that collects solid matter attached to the surface of the sample No. 0 and performs component analysis. The output side of the ash analyzer 58 and the output side of the temperature reading device 35 are connected to a control device (not shown) of the heating furnace 50.

The surface of the detector 10 at the tip of the probe tube 1 is disposed so as to be always perpendicular to the direction in which the solid matter 56 such as combustion ash falls from the filter 54. Further, the vibrator 5 is provided at an arbitrary position of the filter 54.
5 is installed, and by the operation of the vibrator 55, solids 56 such as combustion ash trapped in the filter 54 continuously drop from the filter 54.
New solids will always adhere to the surface of the. The detector 10 at the tip of the probe tube 1 has a detachable structure so that it can be arbitrarily exchanged in order to periodically take out the attached solid matter and perform component analysis.

Detector 10 at the tip of probe tube 1
The dew point temperature at the time of the solid matter adhering to the surface of the is continuously recorded by the temperature reading device 35.

On the other hand, in the solid component analysis performed in parallel with the measurement of the dew point temperature, the probe tube 1 is periodically extracted by the ash analyzer 58 to collect the solid attached to the surface of the detector 10. Will be implemented. The solid component analysis result and the dew point temperature are used as feedback signals for the heating furnace 5
This system is a dew point measuring system that can be fed back to the low-temperature corrosion prevention measures during furnace operation and shutdown by monitoring the corrosive environment conditions from the data related to the two and sent to the control device.

FIG. 3 is a schematic view showing the structure of the dew point meter, FIG. 4 is a schematic partially cutaway view showing a part of the dew point meter shown in FIG.
FIG. 5 is a view on arrow A in FIG. As shown in FIGS. 3 to 5, the dew point meter includes an adapter tube 20 provided through the flue wall 38 of the bypass line 53, a probe tube 1 inserted through the adapter tube 20, and a probe tube 1. It is configured to include a detector 10 attached to the distal end, and a water washing tube 13 opened toward a detection plate on the surface of the detector 10. Probe tube 1
Is connected to a cooling air control unit 2 via a cooling air supply pipe 21, and the cooling air control unit 2 is connected to the adapter tube 20 via a cleaning water supply pipe 22. It is connected. The washing water supply pipe 22 is connected to the water washing tube 13 via the adapter tube 20.

The cooling air control unit 2 includes a solenoid valve 23 having a cleaning water outlet side connected to an upstream end of the cleaning water supply pipe 22, and a cooling air supply device connected to a cooling air inlet side of the solenoid valve 23. 45 and an air flow control unit 28 connected to the cooling air outlet side of the solenoid valve 23.
And a motor 29 for driving the airflow control unit 28. Further, a cleaning water main pipe 24 is connected to the cleaning water inlet side of the solenoid valve 23. The solenoid valve 23 includes a cleaning water main pipe 24 and a cleaning water supply pipe 22.
Position, a neutral position where none of the pipes are connected, a cooling air supply device 45 and an air flow control unit 28.
Can be controlled to three positions of the cooling air supply position that communicates with each other.

The electronic control unit 3 includes an ammeter 32, an amplifier 33, and an ammeter 32 connected to the detector 10, respectively.
, A linearizer 34 connected to the amplifier 33, a temperature gauge 37 and a temperature reading device 35 connected to the linearizer 34, and a timing device 36 connected on the output side to the temperature reading device 35.
And is configured. ing. The output side of the timing device 36 is further connected to the solenoid valve 23, and the output side of the motor control unit 31 is connected to the motor 29 of the cooling air control unit 2.
That is, the solenoid valve 23 is connected to the timing device 36.
Supply / stop of cleaning water, supply of cooling air /
It is configured to stop.

FIGS. 6 and 7 show examples of the surface condition of the detection plate 4 of the detector 10 at the tip of the probe tube 1. FIG. This is an example in which solid deposits 8 such as combustion ash and chloride easily adhere to the surface of the detection plate 4, and the surface is formed with a sawtooth groove 41 and a wavy groove 43 to prevent falling off.

As a result, the deposit 8 can easily adhere to the surface of the detection plate 4 uniformly, so that it is possible to prevent dew condensation from being locally unevenly distributed. Therefore, the dew point temperature can be accurately measured.

Next, a method of using the dew point temperature measuring device of the above embodiment will be described with reference to FIGS. As shown in the enlarged schematic diagrams of FIGS. 4 and 5, the tip of the dew point meter is attached to the detection plate 4 of the detector 10 at the tip of the probe tube 1 on the flue side.
Is configured to be located. The configuration itself of the detector 10 is the same as that shown in FIG.
The tip of the dew point meter thus configured is installed at an arbitrary position directly below the filter 54 installed in the bypass line 53 of FIG. The detector 10 is attached to the probe tube 1 with an attachment screw 44 as shown in FIG.
It is removable. The surface of the detection plate 4 of the detector 10 is installed perpendicularly (that is, almost horizontally) to the falling direction of the combustion ash. FIG. 2 is an enlarged schematic diagram of the vicinity of the dew point meter. The vibrator 55 is attached to the filter 54, and the solid matter collected by the filter 54 is shaken off by vibration. It is possible to drop solids. The detector 10
The old solid matter adhering to the surface is removed by washing appropriately with washing water jetted from the water washing tube 13 shown in FIG. In addition, old solid matter is removed by periodically extracting the probe tube 1 and cleaning the detector 10 at the tip thereof. As a result, the dew point temperature under the condition that a new solid substance adheres is always recorded on the temperature reading device 35 in real time. Furthermore, the solid matter (ash) analyzer 58 shown in FIG. 1 performs the component analysis of the attached matter in parallel with the measurement of the dew point temperature, thereby clarifying the relationship between the dew point temperature and the attached component, and preventing low-temperature corrosion. As a result, the analysis result of the solid (ash) analyzer 58 is output as a feedback signal 57 to the control device of the heating furnace 50, and the furnace is operated so that the solid component having a low dew point is discharged in response to this signal. Will be reflected.

The measurement of the dew point temperature is performed as follows.
First, the solenoid valve 23 is switched to supply cooling air into the probe tube 1 to cool the detection plate 4. The detection plate is dewed by cooling, and the temperature at which a current starts flowing between the platinum ring electrode 5 and the thermocouple 6 due to the dew is detected by the thermocouple 6. Then, when current starts flowing between the platinum ring electrode 5 and the thermocouple 6 due to dew condensation, the solenoid valve 23 shown in FIG.
Turn off the cooling air supply. When the supply of the cooling air is stopped, the temperature of the detection plate 4 rises and the dew condensation on the surface of the detection plate 4 evaporates, so that no current flows between the platinum ring electrode 5 and the thermocouple 6. Thereafter, by switching the solenoid valve 23 again and supplying cooling air into the probe tube 1 to cool the detection plate 4, the dew point temperature can be continuously measured.

On the other hand, the timing device 36 switches the solenoid valve 23 at a predetermined time interval, and connects the cleaning water main pipe 24 to the water cleaning tube 13 via the cleaning water supply pipe 22 for a predetermined time. . By this operation, the surface of the detection plate 4 of the detector 10 is washed with the washing water spouted from the water washing tube 13, and the old solid matter adhering to the surface is removed.

The timing device 36 is also provided on the vibrator 55.
Sends a control signal, and stops the vibration during the cleaning operation. The vibrator 55 may be continuously vibrated at all times, may be intermittently vibrated at a preset time interval, or may be a control signal (for example, cleaning) transmitted from the timing device 36. The operation may be performed in response to a signal indicating the end, but in any case, the vibration is stopped during the cleaning operation.

In the above description, when a current starts flowing between the platinum ring electrode 5 and the thermocouple 6 due to dew condensation, and when the dew condensation evaporates, the platinum ring electrode 5 and the thermocouple 6
When the current stops flowing between the solenoid valves, the solenoid valve 23 is switched. Instead of switching the solenoid valve 23 according to the presence or absence of the current between the platinum ring electrode 5 and the thermocouple 6, the cooling air supply device 45 and the air flow control unit 28 are always used except when the detector is washed.
The motor control unit 31 is operated based on current information sent from the ammeter 32 according to the presence or absence of a current between the platinum ring electrode 5 and the thermocouple 6, and the motor control unit 31 May be driven to control the supply of cooling air to the probe tube 1.

[0031]

According to the present invention, the dew point temperature of the exhaust gas environment can be continuously measured in a state where solid matter such as combustion ash adheres. The system that performs the component analysis in parallel allows the operating conditions at the time of starting and stopping the furnace to be determined from the viewpoint of preventing dew point corrosion.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing a main configuration of a dew point temperature measuring device according to a first embodiment of the present invention.

FIG. 2 is an enlarged schematic view showing a part of FIG. 1;

FIG. 3 is a conceptual diagram showing a schematic configuration of the dew point meter shown in FIG.

FIG. 4 is a side view showing a part of the dew point meter shown in FIG. 3 by a cut surface.

FIG. 5 is a view taken in the direction of the arrow A in FIG. 4;

FIG. 6 is a schematic view showing an example of a cross section of a dew point meter tip detection plate according to the present invention.

FIG. 7 is a schematic view showing another example of the cross section of the dew point meter tip detection plate according to the present invention.

FIG. 8 is a conceptual diagram showing a configuration example of a conventional dew point measuring device.

FIG. 9 is an enlarged view taken in the direction of the arrow C in FIG. 8;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Probe tube 2 Cooling air control unit 3 Electronic control unit 4 Detector plate 5 Platinum ring electrode 6 Thermocouple 8 Attached substance 10 Detector 13 Water washing tube 14 Cooling air supply pipe 15 Air discharge pipe 16 Gas temperature measuring thermocouple 20 Adapter tube 21 Cooling air supply pipe 22 Wash water supply pipe 23 Solenoid valve 24 Wash water main pipe 28 Air flow control unit 29 Motor 31 Motor control unit 32 Ammeter 33 Amplifier 34 Linearizer 35 Temperature reading device 36 Timing device 37 Temperature gauge 38 Flue wall 40 Air discharge pipe 41 Saw groove 43 Wavy groove 44 Mounting screw 45 Cooling air supply device 46 Electrode thermocouple output signal 47 Signal processing circuit 48 Dew point / gas temperature meter 49 Current / P
BU meter 50 heating furnace 51 electric dust collector 52 chimney 53 bypass line 54 filter 55 vibrator 56 solid matter such as combustion ash 57 feedback signal 58 ash analyzer 59 flue

Claims (7)

[Claims] 1. A dew point temperature measuring device which is installed in a flue through which a combustion gas containing solid matter discharged from a furnace flows and measures a dew point temperature of the combustion gas by dew condensation on a condensation surface of a detector. A bypass line that branches off a part of the combustion gas, a filter that is provided in the bypass line to remove solid substances such as combustion ash in the combustion gas, And a dew point meter having a detector attached thereto. 2. The dew point temperature measuring apparatus according to claim 1, further comprising a vibrator for vibrating the filter. 3. A dew condensation surface of a detector attached to the tip of the probe tube is perpendicular to a falling direction of a solid substance such as combustion ash attached to the filter, and the solid substance adheres to a surface of the detector. The dew point temperature measuring apparatus according to claim 1, wherein the dew point temperature can be continuously measured in a state where the temperature is set. 4. The dew point temperature measuring device according to claim 1, wherein an uneven groove is provided on a dew surface of the detector. 5. The dew point temperature measuring device according to claim 1, further comprising a washing unit for spraying washing water onto a dew surface of the detector for washing. 6. The solid matter analyzer according to claim 1, further comprising a solid matter analyzer that analyzes a component of the solid matter attached to the condensation surface of the detector and outputs an analysis result. Dew point temperature measurement device. 7. A method for measuring the dew point temperature of a combustion gas discharged from a furnace, wherein the dew point temperature of the combustion gas and the solid matter such as combustion ash are measured and the solid matter is analyzed to determine the dew point temperature and the solid matter of the solid matter. A dew point temperature measuring method characterized in that the relationship between components is recorded and can be fed back to a low-temperature corrosion prevention measure.