JPH0225624A - Temperature control of cyclone coal combustion furnace - Google Patents

Abstract

PURPOSE:To make it possible to control the temperature of the furnace wall even during the operation under a low load by utilizing air used for secondary combustion and air used for two-stage combustion for cooling the body of a furnace and at the same time controlling the amount of circulation of cooling air while the temperature of the furnace wall is sensed. CONSTITUTION:After the main body 2 of a cyclone is cooled by supplying combustion air to a cooling air flow channel 18 which is between the inner plate 16 and outer plate 17 of the main body 2 of the cyclone, the combustion air is used as secondary air and two-stage combustion air. And part of exhaust gas from the combustion of a secondary furnace is used with the combustion air for cooling the main body 2 of the cyclone by circulating the exhaust gas and combustion air, and the temperature of the inner plate 16 is sensed and the opening and closing of a damper 28 or a valve in a line 27 of the circulating air are made after the main body 2 of the cyclone is cooled in order to regulate the volume of the circulating air sent to a cooling gas flow channel 18. Namely, the volume of the circulating air is regulated by the damper 28 or the valve in order to prevent an excessive rise in the temperature of the inner plate 16. And, the surface temperature of a refractory material 32 which is lined on the inner plate 16 is sensed and a damper 34 or a valve of a circulation line 25 of the exhaust gas from the combustion is controlled by its opening or closing.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention uses an industrial furnace such as a boiler furnace as a furnace body, and uses solid fuel such as pulverized coal, pulverized oil coke, or sludge (hereinafter referred to as The present invention relates to a temperature control method for protecting inner plates such as refractory materials and inner cavity plates of a cyclone coal combustion furnace in which coal (simply referred to as coal) is combusted by swirling air for combustion.

[Conventional technology]

BACKGROUND ART Conventionally, industrial furnaces such as boiler furnaces are known in which a cyclone coal combustion furnace is provided as a front furnace (-furnace) in the furnace body to partially burn coal.

Industrial furnaces (secondary furnaces) equipped with such forehearths are widely used because of their excellent combustion effects.

As an illustration of the structure of the above-mentioned conventional cyclone coal combustion furnace, for example, the previously proposed Utility Model No. 607671.7
As shown in the publication, a structure in which pulverized coal is partially combusted by supplying pulverized coal and air into a cyclone coal combustion furnace and effectively mixing and burning them as a high-speed swirling flow. is disclosed. That is, as shown in FIG. 4, the cyclone main body 2 is attached laterally to the side wall of a furnace (secondary furnace) 1 such as a boiler furnace,
The cyclone body is provided with a coal input port 3, a swirling air supply port 4 for combustion, and a gas communication port 5 for guiding combustion gas to the furnace, and the combustion gas generated within the main body 2 is passed through the cyclone body 2 to melt it. A cyclone coal combustion furnace 8 is described that is provided with a slag pan fluro for damming up slag, and a downward slag flow lower is provided on the combustion gas upstream side of the slag pan flue. 10 is a slag tank, 11 is a combustion chamber, 12 is a bypass line, and 13 is a flame.

Also in 1967
"'LARGE ROII JRFullNACES", published by NG COMPANY (Netherlands), describes a method and apparatus for cooling a cyclone coal-fired furnace by passing air between its inner and outer plates.

Furthermore, a method of controlling combustion temperature and refractory material temperature by providing a combustion furnace with a combustion exhaust gas circulation inlet and circulating the combustion exhaust gas has also been known.

[Problem that the invention seeks to solve]

In the cyclone coal combustion furnace shown in Figure 4 above,
In order to protect the fireproof materials and inner steel plates around the cyclone body, it is necessary to cool them.

Further, in the cyclone coal combustion furnace described in the above-mentioned Dutch document, since the amount of cooling medium cannot be secured during low-load operation, there are disadvantages such as an excessive rise in the temperature of the inner cavity plate and damage.

Furthermore, in the method of installing the combustion exhaust gas circulation line mentioned above,
If the amount of circulating exhaust gas is increased, the surface temperature of the refractory material and the temperature of the inner cavity plate will decrease; however, during low load operation, the surface temperature of the refractory material may drop too much and cause combustion troubles.

In addition, in a cyclone coal combustion furnace, the appropriate range of refractory material surface temperature is extremely narrow due to restrictions on ensuring the melt fluidity of slag.

The present invention was made in view of the above points, and is designed to protect both the refractory material and the metal surface that make up the inner wall of the furnace over a wide range of operating loads in an air-cooled cyclone coal combustion furnace. Both of the two-stage combustion air is used as furnace cooling air, and in order to prevent the amount of furnace cooling air from decreasing during low-load operation, a furnace cooling air circulation line is installed to detect the temperature of the furnace wall. It is an object of the present invention to provide a method that can control the furnace wall temperature even during low-load operation by controlling the amount of circulating cooling air.

[Means and operations for solving the problems] In order to achieve the above object, the temperature control method in a cyclone coal combustion furnace of the present invention includes a cyclone main body 2 on the side wall of the secondary furnace 1, as shown in the drawings. is attached laterally, and the cyclone coal combustion furnace 8 is equipped with a coal input port 3, a swirling air supply port 4 for combustion, a gas communication port 5 for guiding combustion gas to the secondary furnace, and a slag flow lower lower in the cyclone body. After cooling the cyclone body 2 by supplying air to the cooling gas passage 18 between the inner plate 16 and outer plate 17 of the cyclone body 2, the air is used as secondary air and second-stage combustion air, and is then used as secondary air and second-stage combustion air. A part of the combustion exhaust gas is circulated together with the combustion air to cool the cyclone body 2, and the temperature of the inner plate 16 is detected to open and close the damper 28 or valve of the circulating air line 27 after cooling the cyclone body 2. It is characterized by controlling and adjusting the amount of circulating air sent to the cooling gas flow path 18. That is, in order to prevent the temperature of the inner plate 16 from rising excessively, the amount of circulating air is adjusted using the damper 28 or the valve.

Furthermore, the method of the present invention cools the cyclone body 2 by supplying combustion air to the cooling gas passage 18 between the inner plate 16 and the outer plate 17 of the cyclone body 2, and then supplies the secondary air and the second stage combustion air. Furthermore, a part of the combustion exhaust gas from the secondary furnace is circulated together with the combustion air to cool the cyclone body 2, and the surface temperature of the refractory material 32 lined with the inner plate 16 is detected, and the combustion exhaust gas is circulated. It is characterized by controlling the opening and closing of the damper 34 or valve of the line 25. That is, in order to control the surface temperature of the refractory material 32, the amount of circulating exhaust gas is adjusted using the damper 34 or the valve. Note that the combustion exhaust gas line 24 may be taken out from any part of the smoke inlet from the boiler outlet.

〔Example〕

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. However, unless there is a specific description, the materials, shapes, relative positions, etc. of the components described in this example are not intended to limit the scope of the present invention to these, but are merely illustrative. Just an example.

FIG. 1 shows an example of an apparatus for implementing the temperature control method in a cyclone coal combustion furnace of the present invention. Combustion air is sent to an air preheater 15 by a forced fan 14 and heated there, and then the heated combustion air is passed between an inner plate 16 such as an inner mesh plate of the cyclone body 2 and an outer plate 17 such as an outer steel plate. The cyclone body 2 is cooled by being supplied to the cooling gas flow path 18 between the two.

The air exiting the cooling gas flow path 18 is used as secondary air and second stage combustion air. 20 is a secondary air line, 21
is a two-stage combustion air line.

Also, a part of the combustion exhaust gas from the secondary furnace 1 such as a boiler furnace is circulated and used together with the combustion air for cooling the cyclone body 2, and the remaining combustion exhaust gas passes through the air preheater 15 and the induction fan 22, and then flows out from the chimney 23. It is discharged. 24 is a combustion exhaust gas line, and 25 is a combustion exhaust gas circulation line.

Then, the temperature of the inner plate 16 is detected by the temperature detector 26, and the damper 28 of the air circulation line 27 through which the circulating air after cooling the cyclone body 2 flows is controlled to open and close, and the circulating air is sent to the cooling gas flow path 18. Adjust the amount. 30 is a control device;
31 is a circulation fan.

If the temperature detected by the temperature detector 2B (temperature of the inner plate) is too high, the damper 28 is opened to increase the amount of circulating air.

The inner plate 16 is lined with a refractory material 32, and the surface temperature of the refractory material 32 is detected by a temperature detector 33 to control the opening and closing of the damper 34 of the combustion exhaust gas circulation line 25.

35 is a control device.

When the temperature detected by the temperature detector 33 is high, the damper 34 is opened to increase the circulation amount of the combustion exhaust gas, thereby controlling the surface temperature of the refractory material 32 to be lowered.

In addition, to take the temperature of each part as an example, the air preheater 15
The air temperature at the outlet is around 200'C, the air temperature at the outlet of the cooling gas flow path 18 is around 600'C, and the combustion exhaust gas temperature at the outlet of the secondary furnace 1 is around 300'C. a) is the secondary air amount, (b) is the second stage combustion air amount, F
C) shows the amount of circulating air after cooling, and (d) shows the amount of circulating combustion exhaust gas.

FIG. 2 shows the results of actually measuring the relationship between the temperature of each part in the cyclone coal combustion furnace and the combustion load. In FIG. 2, the solid line shows the measured value in the conventional case without circulation, and the broken line shows the measured value in the case of implementing the method of the present invention including air circulation and combustion exhaust gas circulation.

FIG. 3 shows an example of actual measurement of each amount of air and amount of circulating combustion exhaust gas when the method of the present invention is implemented.

Note that (a) to (b) are the same as shown in FIG.

〔Effect of the invention〕

Since the present invention is configured as described above, it is possible to control the temperature of the refractory material, inner mesh plate, etc., and therefore, it has the effect of being able to prevent damage to the materials due to excessive rise in temperature. are doing.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing an example of a device implementing the temperature control method in a cyclone coal combustion furnace of the present invention, Fig. 2 is a diagram showing the relationship between combustion load and temperature of each part, and Fig. 3 is a combustion load FIG. 4 is a sectional view showing an example of a conventional cyclone coal combustion furnace. 1... Furnace (secondary furnace), 2... Cyclone body, 3
... Coal input port, 4... Combustion swirling air supply port, 5
...Gas communication port, 6...Slag baffle, 7...
Slag outlet, 8...Cyclone coal combustion furnace, 10.
... Slagta 7ri, 11 ... Combustion chamber, 12 ... Bypass line, 13 ... Flame, 14 ... Forced fan,
15... Air preheater, 16... Inner plate, 17... Outer plate, I8... Cooling gas flow path, 20... Secondary air line, 21... Two-stage combustion air line, 22... Induction fan, 23... Chimney, 24... Combustion exhaust gas line,
25... Combustion exhaust gas circulation line, 26... Temperature detector, 27... Air circulation line, 28... Damper, 3
0...Control device, 31...Circulation fan, 32...
Fireproof material, 33... Temperature detector, 34... Damper, 3
5-... Control 1 device

Claims (1)

[Scope of Claims] 1. A cyclone body is installed horizontally on the side wall of the secondary furnace, and the cyclone body has a coal input port, a swirling air supply port for combustion, a gas communication port for guiding combustion gas to the secondary furnace, and a slag flow downstream. In a cyclone coal-burning furnace equipped with a port, combustion air is supplied to the cooling gas flow path between the inner and outer plates of the cyclone body to cool the cyclone body, and then used as secondary air and second-stage combustion air. Furthermore, part of the combustion exhaust gas from the secondary furnace is circulated together with the combustion air to cool the cyclone body, and the internal plate temperature is detected and a damper or valve in the circulating air line after cooling the cyclone body is activated. A temperature control method in a cyclone coal combustion furnace, characterized by controlling opening and closing to adjust the amount of circulating air sent to a cooling gas flow path. 2. A cyclone coal system in which a cyclone body is installed horizontally on the side wall of the secondary furnace, and the cyclone body is provided with a coal input port, a swirling air supply port for combustion, a gas communication port for guiding combustion gas to the secondary furnace, and a slag flow port. In the combustion furnace, combustion air is supplied to the cooling gas flow path between the inner plate and the outer plate of the cyclone body to cool the cyclone body, and then used as secondary air and second stage combustion air, and is then used as secondary air and second stage combustion air. A part of the combustion exhaust gas is circulated together with the combustion air to cool the cyclone body, and the surface temperature of the refractory material lined on the inner plate is detected to control the opening and closing of dampers or valves in the combustion exhaust gas circulation line. Characteristics of temperature control method in cyclone coal combustion furnace.