JP2523297Y2 - Catalytic combustion device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catalytic combustion apparatus which uses an oxidation catalyst excellent in far-infrared radiation efficiency and is used for heating and drying.

[0002]

2. Description of the Related Art A catalytic combustion apparatus in which a gaseous fuel and a vaporized liquid fuel are mixed with air and then sent to a catalyst layer to be brought into contact with a catalyst and to perform flameless combustion on the surface thereof has no emission of nitrogen oxides. Since it has excellent features such as realizing mild radiant heating by the effect of far-infrared rays radiated from the catalyst layer, various proposals have been conventionally made and some of them have been put to practical use.
Conventionally, as an example of such a catalytic combustion device using a radiant heat generated from a catalyst layer using a heat-resistant inorganic material for a carrier, a catalyst having a structure as shown in FIGS. There is a combustion device. Referring to the figure, 1 is a catalytic combustion tube, 3 is a mixing chamber, 5 is a blower, 6 is an exhaust duct, 7 is a guard net, 8 is a reflector, 11 is a catalyst pellet, 12 is heat resistant glass, and 13 is for preheating. Heater, 14
Is an electrode, and 16 is a temperature sensor.

[0003] As described above, a plurality of small-sized cylindrical or prismatic catalyst pellets having a cross-sectional shape such as a honeycomb and having excellent air permeability are inserted into a heat-resistant glass cylinder. Insert a resistance-heat-generating inorganic material formed into a shape with excellent air permeability such as a honeycomb together with the electrode to form a catalytic combustion tube, and set one or more of the catalytic combustion tubes to supply a premixed gas from below. In this structure, a reflecting plate is provided behind the catalytic combustion cylinder to reflect infrared rays emitted from the catalyst pellets to the front through heat-resistant glass.

[0004]

The above-described conventional catalytic combustion apparatus has the following drawbacks.

That is, during steady-state combustion, among the catalyst pellets inserted into the catalytic combustion cylinder, those located closer to the uppermost stream (inlet) are always in a red-hot state (6) regardless of the amount of combustion.
(50 to 800 ° C.), so that the catalyst activity gradually decreases due to thermal degradation while the operation is continued, and finally, the vicinity of the inlet does not undergo a combustion reaction, and the combustion start point shifts to the downstream side. At this time, if the total volume of the catalyst pellets is designed so that there is not enough room for the space velocity (SV value) at the time of the maximum combustion amount, unburned gas is discharged from the most downstream part (exit part) of the catalyst pellets. It is dangerous.

In addition, the temperature of the inlet portion where combustion does not occur during steady combustion is lower than that in the original state. At this time, when using a liquid fuel vaporized as fuel,
In some cases, carbon starts to adhere to the vicinity of the inlet portion where the temperature has dropped, and this carbon causes bright flame combustion to cause abnormal combustion such as accelerating sintering of the catalyst layer.

Further, when the catalytic activity at the entrance of the catalyst pellets is reduced, flashback tends to occur. Therefore, as a method of detecting the temperature drop at the inlet of the catalyst pellet due to the service life, a method using a temperature sensor can be considered. However, it is difficult to directly contact the catalyst layer on the structure to detect the temperature, and the response is poor. , Poor reliability.

[0008]

SUMMARY OF THE INVENTION A catalytic combustion device according to the present invention has been made in order to solve the above-mentioned problem, and has a color sensor for detecting the life based on the luminance of red heat of a catalyst pellet and supporting the color sensor. A sensor unit consisting of a covering member that has a detection hole in front of the sensor and is provided around the heat-resistant glass cylinder at the most upstream part of the catalyst pellet, and the output of the color sensor is connected to the control unit It is.

[0009]

In the above configuration, the inlet-side catalyst pellets, which are always in a red-hot state while the operation is continued, undergo thermal deterioration, and the combustion section shifts to the downstream side, and the inlet section does not cause a combustion reaction, and the temperature becomes lower. And the red heat luminance decreases. When the glow decreases to a certain value, a control unit (not shown) that obtains the output of the color sensor for life detection disposed across the heat-resistant glass cylinder detects the life of the catalyst pellet by a change in the output of the color sensor. Since it is possible to take measures such as automatically stopping the operation and turning on a lamp for notifying the user of catalyst deterioration, unburned gas is not discharged.

Further, when the deterioration of the catalyst is automatically detected in this manner, the deteriorated catalyst pellets on the inlet side are repositioned at the most outlet side of the catalyst pellet assembly, and the other catalyst pellets are shifted to the inlet side by one stage. The operation can extend the life of catalytic combustion.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS.

In the catalytic combustion device according to the present invention, FIG.
As shown in FIG. 4, reference numeral 1 denotes a catalytic combustion tube, and one or a plurality thereof stands in a vertical direction. Reference numeral 2 denotes a diffuser chamber, which is a box-shaped chamber which firmly supports the catalytic combustion tube 1 from below and uniformly supplies the premixed gas sent from the bottom opening to the ceiling opening communicating with the catalytic combustion tube. Reference numeral 3 denotes a mixing chamber, which mixes fuel sent from an oil feed pump (not shown) through an oil feed pump 4 with combustion air pumped from a blower 5 to generate a premixed gas. When the fuel is liquid fuel, a heater for vaporizing the fuel is provided in the mixing chamber 3. Reference numeral 6 denotes an exhaust duct, which is a box-shaped chamber that firmly supports the catalytic combustion cylinder 1 at the upper portion and collects combustion gas sent from a bottom opening communicating with the catalytic fuel cylinder and discharges the combustion gas to the atmosphere from the upper opening.

The catalytic combustion cylinder 1 is mainly composed of a cylindrical heat-resistant glass cylinder 12 having an excellent heat transmittance, a cordierite molded into a columnar or prismatic section having a honeycomb structure or the like and having an excellent air permeability such as a honeycomb structure. Preliminary heat-resistant inorganic material such as silicon carbide in the same shape as the catalyst pellets and several 11 catalyst pellets using the above heat-resistant inorganic material as a carrier and carrying an oxidation catalyst such as a platinum group metal on the surface. Heater 13
In the heat-resistant glass tube 12, a preheating heater 13 is inserted at the most upstream portion on the inlet side, and several catalyst pellets 11 are stacked and inserted on the upper downstream portion thereof. Electrodes for applying a voltage are attached to two places on the outer periphery of the preheating heater 13, and a connection portion of the lower end portion with the diffuser chamber 2 is insulated and held by an insulating sealant.

Reference numeral 16 denotes a temperature sensor which is attached to the uppermost part of each catalytic combustion cylinder 1. Numeral 7 denotes a guard net which surrounds the catalytic combustion cylinder 1 which becomes high during operation to ensure safety. Reference numeral 8 denotes a reflection plate, which is arranged in the cabinet 9 so as to surround the rear of the catalytic combustion tube 1. A hot air outlet 10 is located on the ceiling of the cabinet 9 and discharges hot air discharged from the exhaust duct 6 upward. Reference numeral 17 denotes a sensor unit which is mounted on a partition plate 21 below each of the catalytic combustion cylinders. An 18 color sensor is fixedly supported in the sensor unit, and the entire color sensor is surrounded by a covering member 19 so that light from other than the catalyst pellets does not enter.

Further, a detection hole for taking in red light from the catalyst pellet is opened in the covering member in front of the color sensor toward the catalyst pellet. Reference numeral 20 denotes a lead wire for transmitting the output of the color sensor to a control unit (not shown) through a hole provided in the partition plate 21.

In the above-structured catalytic combustor, during the normal steady-state combustion, the amount of combustion air is controlled so that the one located at the most upstream part among the catalyst pellets 11 is always in a red-hot state regardless of the amount of combustion. It emits red light through the heat-resistant glass tube to the surroundings. Therefore, a sufficient amount of red light is emitted to the sensor 18 through the detection hole of the sensor unit 17, and the color sensor 18 which outputs an output signal according to the red light luminance outputs a certain output signal irrespective of the combustion amount and obtains this signal. The control unit determines that normal steady-state combustion is performed.

However, the activity of the catalyst pellets is greatly reduced due to thermal deterioration as the catalytic combustion continues. In particular, the most upstream catalyst pellets maintained in a red-hot state irrespective of the amount of combustion are remarkable. In the part where the activity has decreased, the combustion reaction by the catalytic oxidation of the premixed gas supplied from the diffuser chamber 2 becomes difficult, and the combustion reaction shifts to the downstream side.

Due to such deterioration, the temperature distribution in the flow direction of the catalyst pellets decreases as shown in FIG. 4 at the uppermost surface of the catalyst pellets, and the highest temperature position shifts to the downstream side. At this time, since the reddish luminance decreases due to the temperature decrease in the uppermost stream portion of the catalyst pellet, the color sensor 18 detects the decrease in luminance and outputs a signal according to the luminance, and the control unit determines abnormality such as the life of the catalyst. . And
Turn on the warning lamp or perform automatic digestion by the control unit.

Even in the most upstream catalyst pellets determined to have reached the end of the life by the above means, the catalytic activity is maintained at the downstream side, so that the control unit is set so that the life judgment is made in a state of light deterioration. Is to extend the life of the catalytic combustor by removing the uppermost catalyst pellet from the combustion cylinder 12, changing the direction so that the deteriorated surface is on the downstream side, and inserting it again at the most downstream part of the combustion cylinder. Can be.

[0020]

The catalytic combustion apparatus according to the present invention is a catalytic combustion apparatus using a catalytic combustion cylinder formed by inserting a plurality of small-sized cylindrical or prismatic honeycomb sectional catalyst pellets into a heat-resistant glass cylinder. The sensor unit, which consists of a color sensor that detects the service life based on the brightness of the red heat of the catalyst pellet and a covering member that supports the color sensor and encloses the whole and has a detection hole in front of the sensor, The output of the color sensor is connected to the control unit, which is placed around the outer periphery of the glass tube. This produces the following effects.

That is, a control unit that obtains the output of the color sensor for detecting the life detects the life of the catalyst pellets based on a change in the output of the color sensor, and automatically stops the operation and informs the user of the deterioration of the catalyst to the user. Therefore, it is possible to take measures such as turning on the lamp, so that unburned gas is not discharged.

Further, when the deterioration of the catalyst is automatically detected in this manner, the deteriorated catalyst pellet on the inlet side is relocated to the most outlet side of the catalyst pellet assembly, and the other catalyst pellets are shifted one step at a time toward the inlet side. The operation can extend the life of the catalytic combustor.

[Brief description of the drawings]

FIG. 1 is an overall view showing a conventional example.

FIG. 2 is a sectional view of a conventional catalytic combustion cylinder showing a conventional example.

FIG. 3 is a sectional view of a catalytic combustion cylinder showing an embodiment of the present invention.

FIG. 4 Sensor unit

FIG. 5 is an example of a temperature distribution in a flow direction of a catalyst pellet.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Catalytic combustion cylinder 3 Mixing chamber 5 Blower 10 Hot air port 11 Catalyst pellet 12 Heat resistant glass 13 Preheating heater 16 Temperature sensor 17 Sensor unit 18 Color sensor 19 Coating member

Claims (1)

(57) [Scope of request for utility model registration] 1. A catalyst pellet formed by molding an oxidation catalyst layer having excellent air permeability such as a honeycomb into a small cylindrical or prismatic shape, and forming a plurality of catalyst pellets in a heat-resistant glass cylinder having excellent heat permeability. One or a plurality of inserted catalytic combustion cylinders are provided, and a flow path is formed so that a premixed gas obtained by mixing gaseous fuel or vaporized liquid fuel with combustion air passes from below. In a catalytic combustion device in which a reflection plate that causes flameless combustion in the catalyst pellets and reflects the radiant heat from the catalyst pellets forward through the heat-resistant glass cylinder is arranged behind the catalyst combustion cylinder, the outermost position of the heat-resistant glass at the most upstream part of the catalyst pellets And a sensor unit comprising a color sensor for detecting life and a covering member surrounding the entire sensor and having a detection hole in front of the sensor. Baked apparatus.