JPS5864412A - Catalytic combustion equipment - Google Patents

Abstract

PURPOSE:To enable to detect the completion of preheating, slip, abnormal heating and the like of a catalytic combustion layer by measuring the temperature change of the catalytic combustion layer and consequently improve the safety and reliability of the equipment by a structure wherein a temperature detecting element is provided on the outer wall of a combustion tube at the location, to which the catalytic combustion layer is fixed. CONSTITUTION:In the titled equipment, liquid fuel supplied from a feed oil 29 and combustion air charged by means of a fan 8 are pre-mixed in an evaporation premixing chamber 16 and then sent through a resistance plate 15 and a straightening element 18 into a space 21 to be ignited and burnt there. Consequently, the catalytic combustion layer 20 is preheated with a small flame produced within the space 21. In this case, when the temperature of said layer 20 reaches the predetermined temperature, a controlling circuit (not shown) is assumed to be changed-over by means of the temperature detecting element 25 provided on the outer wall of the combustion tube 13. Concretely, air is increased to the flow amount, at which the oxidation reaction in the combustion layer 20 is allowed, by controlling a damper and, after the increase of the air, controlled so as to be increased to the steady flow amount with a suitable time lag after the extinction of lifted flame.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is an apparatus for supplying a premixed gas prepared by premixing gaseous fuel or gaseous fuel obtained by vaporizing liquid fuel and air to a catalytic combustion layer to cause a catalytic oxidation reaction. , it detects when the device starts up that the temperature has reached sufficient to maintain the catalytic oxidation reaction, and also monitors the temperature of the catalytic combustion layer during steady catalytic combustion, and if blow-out occurs, the temperature is The present invention relates to a detection means for detecting an abnormality.

Conventionally, catalytic combustion equipment has been designed to be more rigid in accordance with turbines and boilers.In addition to the main nozzle that supplies fuel during steady state, a pilot burner is installed, and this pilot burner is burned for a certain period of time to preheat the catalytic combustion layer. Due to insufficient preheating, the fuel is not completely oxidized in the brass-fuel combustion layer, and -
In some cases, carbonized carbon and unburned components were emitted. moreover,
Abnormal conditions such as blow-off and overheating have occurred due to deterioration of catalyst activity or abnormal changes in the amount of supplied air or fuel. In view of these points, the present invention installs a temperature detection element on the outer wall of the combustion cylinder where the catalytic combustion layer is installed, and indirectly measures the temperature of the catalytic combustion layer to detect completion of preheating, blow-out, abnormal overheating, etc. It is something.

A catalytic combustion layer device employing a rotary vaporization method as a vaporization premixing block for liquid fuel is shown as an example in FIG. 1 below, and its configuration will be described.

1 is a cylindrical fan case with a bottom, an air intake inlet 2 is opened at the bottom, and a metal fitting 3 connects the fan case 1 to the outside.
A motor 4 is fixed to the bottom, and a shaft 5 of the motor 4 is inserted into the fan case 1 from an air intake inlet 2 along the center line of the fan case 1. The motor 4 is covered by a motor case 7 having an air intake 6 . A fan 8 is fixed to the shaft 5, and guide blades 9 are fixed to the fan case 1, and these are provided alternately in multiple stages.

On the other hand, a fixing plate 11 having an air supply port 10 in the center is fitted to the other end of the fan case 1, and a combustion tube 13 is attached to the outside of the fan case 1 via a banking 12.

A sheathed heater 14 is installed on the side wall of the combustion tube 13 near the fixed plate 11.
is buried, and resistance plate 1 made of wire mesh or punched metal
5 and the fixed plate 11 is defined as a vaporization premixing chamber 16. Furthermore, a rectifying element 18 which is a honeycomb molded body that performs a rectifying action through a spacer 17, a holding fitting 19, and a catalytic combustion layer 2° are attached to the resistance plate 15 in the combustion tube 13 in this order, and is surrounded by these elements. In the space 21 there is a combustion tube 1
3. The spark plug 22 passes through the holding fitting 19 and enters the space 21
It is fixed so that it faces inside.

The catalytic combustion layer 2o is made of alumina, cordierite, and other materials supporting platinum group metals, oxides of different metals, and the like. 2
Reference numeral 3 denotes a presser fitting that holds the catalytic combustion layer 2o inside the combustion tube 13. The opening at the tip of the combustion tube 13 is connected to a heat exchanger 24, and a detection element 25 according to the present invention is attached to the outer wall of the insertion portion of the catalytic combustion layer 2o of the combustion tube 13.

On the other hand, at the tip of the shaft 5 that passes through the fan case 1 and faces into the vaporizing premixing chamber 16 from the air supply hole 10, there is a cone 26 in the shape of a truncated cone whose diameter increases toward the tip of the shaft 5 from the motor 4 side. The rotating plate 27 is installed at its peripheral end so as to open above the stirring blades 25.

The operation in the above configuration will be explained.

When the heater 14 is energized and the side wall of the vaporization premixing chamber 16 reaches a predetermined temperature, the motor 4 and the electromagnetic pump (not shown) are energized to start supplying air and liquid fuel. The liquid fuel is sent onto the rotating tool 26 through the fuel supply pipe 29, flows along the taper of the cone 26, and when it reaches the rotary plate 27, its rotational force causes it to rotate around the circumference 5.

Vaporization premixing chamber 1 that is scattered in the direction and reaches a constant temperature state
6 It vaporizes when it comes into contact with the wall. On the other hand, the fan 8 sucks air from the air intake port 6 through the air introduction port 2, and the air is sucked into the air supply port 1.
After being sent into the vaporization premixing chamber 16 from the fuel gas, it is homogeneously mixed with the vaporized liquid fuel gas by the action of the mixing plate 280 to form a premixed gas.

The premixed gas passes through the key 1 resistor plate 15 rectifying element 18 and enters the space 21.
Here, the flame is ignited by the spark of the spark plug 22, and a large number of small flames 3o are formed using the large number of small holes provided in the rectifying element 18 as flame ports, and combustion occurs. This state is shown in Figure @2.

The heat obtained by this small flame 30 preheats the catalytic combustion layer 2°. At this stage, the amount of air sent and the amount of liquid fuel supplied must be adjusted to an amount that can form a flame in the small holes of the rectifying element 18. A damper (not shown) that can adjust the flow rate is provided, and an electromagnetic pump (
This is possible by controlling pulses (not shown). The gas temperature after combustion of the small flame 3o that burns in the small holes of the rectifying element 18 reaches 700 to 1oOoC, and when the catalytic combustion layer 20 is preheated to at least about 700C, this is installed on the outer wall of the combustion tube 13. The temperature sensing element 26 detects the temperature secondarily and switches the control circuit (not shown). The amount of air supplied by this switching is first applied to the damper (not shown).
As a result of this action, the amount is increased to the extent that the oxidation reaction in the catalytic combustion layer 20 can be carried out. At this time, there is excess air in the small flame 30 on the rectifying element 18, which becomes a lift flame 31 as shown in FIG. 3 and finally reaches the catalytic combustion layer 20 and then disappears. On the other hand, the amount of liquid fuel supplied is controlled so as to increase to a steady amount after the lift flame 31 is extinguished by setting a suitable time lag from the time when the above-mentioned air amount is increased. By the above operations, the catalytic combustion by flameless catalytic oxidation reaction in the catalytic combustion layer 20 can be brought to a steady state.

Further, if an abnormality as described below occurs after transition to steady catalytic combustion, the temperature of the catalytic combustion layer 2o changes.

1 When the activity of the catalytic combustion layer 2o deteriorates, the amount of oxidation reaction in the catalytic combustion layer 20 decreases, resulting in a blow-off phenomenon in which Co and unburned components are exhausted, and the temperature of the catalytic combustion layer 2o decreases. descend.

2. If the amount of air increases beyond the permissible fluctuation range, the excess air must be heated, which causes a drop in temperature and causes blow-off.

3 On the contrary, if the amount of air decreases significantly, the speed of passing through the catalytic combustion layer 20 will be slow, the amount of reaction on the baffle plate 18 side of the catalytic combustion layer 2 will increase, and the amount of air to be heated will be small, so catalytic combustion will not be possible. The temperature of the layer 20 increases, accelerating deterioration of the bag and catalyst.

4 When the amount of fuel supplied increases beyond the allowable fluctuation range, the temperature of the catalytic combustion layer 2o increases due to the increase in the amount of heat generated in the catalytic combustion layer 2o, and the increase in the amount of reaction in the hot atmosphere is also added. The temperature of the catalytic combustion layer 2o is increased. As a result, this causes a bank, ie, a flame combustion as shown in FIG. 2, deterioration of catalyst activity, and melting of the catalyst carrier.

6 If the amount of fuel supplied decreases, the amount of heat generated decreases, which prevents the catalyst from making full use of its activity, resulting in blow-off. That is, the result is relatively similar to 2.

In this way, in understanding the preheating state of the catalytic combustion layer 2o during ignition and the state of the catalytic combustion layer 20 during steady combustion,
Monitoring the temperature of the catalytic combustion layer 2o is an extremely effective means in terms of device configuration and safety. Catalytic combustion layer 2o
Although it is best to directly measure the temperature at
~1500C), and also needs to be inserted into the small holes of the honeycomb body that constitutes the catalytic combustion layer 2o. Furthermore, direct measurement is difficult due to conditions such as the need to withstand an oxidizing atmosphere. Therefore, in the present invention, a temperature sensing element is attached to the outer wall of the combustion cylinder to which the catalytic combustion layer is fixed, so that the temperature of the catalytic combustion layer is indirectly monitored. Since the temperature detection element is attached to the outer wall of the combustion cylinder, it is sufficiently sensitive to the above-mentioned abnormal phenomena, although there is a delay of about a few seconds to one minute in response to abnormal temperature changes. 1. The temperature sensing element is not particularly required to be resistant to high temperatures; for example, a thermocouple or even a liquid-filled thermostat can be used. In this example, when the catalyst combustion layer temperature was about 1100C at the highest point, the temperature detection element (K thermocouple) showed about 350C.

The present invention provides a temperature detection element on the outer wall of the combustion cylinder at the part where the catalytic combustion layer is fixed, detects abnormal temperature changes, etc., and stops catalytic combustion when an abnormality such as blow-out or back-up occurs. It exhibits excellent performance, allowing for safety measures and the ability to detect the completion of preheating of the catalytic combustion layer.

In this embodiment, a catalytic combustion device using liquid fuel is shown, but gas fuel may also be used, and even in this case, it is sufficient to supply the combustion cylinder as a premixed gas having an appropriate air-fuel ratio.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of a liquid fuel catalytic combustion device according to an embodiment of the present invention, and FIG. 2 is a main part of the catalytic combustion device shown in FIG. FIG. 3, which shows the state, is a main part of FIG. 1, and is a state diagram showing a state in the middle of transition to catalytic combustion. 13... Combustion cylinder, 2o... Catalytic combustion layer, 26... Temperature detection element.

Claims (1)

[Claims] A means for supplying a premixed gas of gaseous fuel and air and a combustion tube equipped with a catalytic combustion layer are provided, and the premixed gas is introduced into the catalytic combustion layer in the combustion tube to perform a catalytic oxidation reaction on the premixed gas. This catalytic combustion device has a configuration in which combustion is performed using the following methods, and a temperature sensing element is attached to the outer wall of the combustion cylinder in the catalytic combustion layer.