JPS63176908A - Combustion furnace - Google Patents

Abstract

PURPOSE:To provide a combustion furnace which is free from deposition of a scale on the inner wall surface of a furnace body and enables continuous combustion operation, by providing a feed port for secondary air for main combustion, a main fuel injection nozzle for forming a main flame, and a feed port for tertiary air for main fuel combustion. CONSTITUTION:Main fuel F, injected through a main fuel injection nozzle 8 toward as assist combustion flame, is burnt by means of secondary air A2 fed from the inner peripheral part thereof and tertiary air A3 fed from the outer peripheral part thereof to form a vertical down main flame at the central part of the interior of a furnace body 1. In this case, since the tertiary air A3 is fed from the peripheral part of the main fuel F toward the main flame, a combustion product is prevented from making direct contact with the inner wall surfaces of a furnace top part 1a and a furnace side wall part 1b. Even when fuel containing an ash content is used as the main fuel F, the ash content forms scales which are adhered on the inner wall surfaces of the furnace top part 1a and the furnace side wall part 1b, and is prevented from growing. This constitution enables execution of long-term continuous operation.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a combustion furnace, for example for generating hot air, using a fuel containing ash or the like.

2. Description of the Related Art Conventionally, a combustion furnace such as a heat generating furnace 8a as shown in FIG. 4 has been used. That is, an annular flame-holding cylinder 22 is provided at the center of the furnace top 21a of the vertical furnace body 21.
A fuel injection nozzle 23, a primary air supply port 24 for combustion, and an auxiliary fuel injection nozzle 25 are arranged in the center thereof,
Furthermore, a secondary air supply port 26 for combustion is provided on the outer surface of the flame stabilizing cylinder 22.

The side wall 21b of the furnace body 21 is formed into a double wall 21c and is water-cooled. A cooling medium injection port 27 is provided outside the furnace body 21 to supply a cooling medium such as water or steam into the furnace. 28 is a swirl vane installed at each air supply port 24 and 26.

Problems to be Solved by the Invention In the conventional combustion furnace described above, in order to stabilize the mixture of fuel F and air A and the flame, a flame stabilizing tube 22 is provided, and the combustion air intake is provided with a swirling blade 28 or the like. As a result, a vortex is generated near the flame stabilizing tube 22 and inside the furnace. In such a combustion furnace, combustion products such as ash are absorbed into the furnace body 21.
When using fuel such as pulverized coal, which has the property of precipitating as scale when it comes into contact with the inner wall surface of the flame-holding tube 2,
Combustion products adhere and grow as a scale 29 on the inner surface of the furnace 2 or the inner wall surface of the furnace body 21, hindering continuous combustion operation.

The present invention solves the above-mentioned problems, and provides a combustion furnace capable of continuous combustion operation in which scale is not deposited on the inner wall surface of the furnace body even when fuel containing ash is used. The purpose is to

Means for Solving the Problems In order to solve the above-mentioned problems, the combustion furnace of the present invention has a vertical furnace body equipped with an auxiliary burner that injects auxiliary fuel vertically into the furnace to form an auxiliary flame. A primary air supply port for auxiliary fuel combustion, a secondary air supply port for main fuel combustion, a main fuel injection nozzle for forming a main flame, and This is characterized by the provision of a tertiary air supply port for main fuel combustion.

Operation In the above configuration, the auxiliary combustion burner ensures a stable auxiliary combustion flame using the auxiliary fuel and primary air, that is, the ignition source for the main fuel, and the secondary air and the main fuel are supplied around the auxiliary flame from the outside. , and tertiary air supplied from the outer periphery to form a vertical main flame in the center of the furnace, and secondary air is supplied to the inner periphery of the main fuel to be supplied, Since tertiary air is supplied to the auxiliary burner, the main fuel is prevented from entering into the auxiliary combustion flame, and scale is prevented from depositing on the inner wall surface near the auxiliary burner. Tertiary air blocks the space between the material and the inner wall surface of the furnace main body, preventing scale from adhering to the inner wall surface and growing, allowing long-term continuous operation.

Example Embodiments of the present invention will be described based on the drawings.

1 and 2 show a combustion furnace according to a first embodiment of the present invention. 1 and 2, a flame stabilizing cylinder 2 is disposed in the central part of the conically shaped furnace top 1a of the vertical furnace body 1 in the core direction (vertical direction) of the furnace body 1, Its lower end 2a opens into the furnace body 1, is formed with a double wall, and the cooling water W is passed inside. An auxiliary combustion burner 3 is inserted into the center of the flame stabilizing tube 2 from above, and a furnace main body 1 is inserted from the bottom inside the flame stabilizing tube 2.
It is arranged so as to form an auxiliary combustion flame directed vertically downward inward. To supply primary air A1 for combustion of auxiliary combustion "j4f" into the flame stabilizing cylinder 2 between the auxiliary fuel supply pipe 3a that supplies the auxiliary fuel f to the auxiliary combustion burner 3 and the upper end 2b of the flame stabilizing pipe $I2. A primary air supply port 4 is provided and a swirling vane 4a is attached thereto, and a primary air supply duct 5 is provided above the upper end 2b of the flame stabilizing tube 2 and the swirling vane 4a.

A slit-shaped secondary air supply port 6 for supplying secondary air A2 into the furnace body 1 is provided in a concentric ring shape on the outer periphery of the flame-holding WJ2, and a plurality of (four) rectifying ports are provided at equal intervals. Board 6a
is provided, and the secondary air A2 is supplied without swirling. A secondary air supply duct 7 is provided above the secondary air supply port 6.

A conical furnace top 1 on the outer periphery of the secondary air supply port 6
A, a plurality of g < 8 @) which supplies the main fuel F into the furnace body 1
One row of main fuel injection nozzles 8 and tertiary air A3 are injected into the furnace body 1.
Multiple 11 feeding inside! Two rows of I (eight) tubular tertiary air supply ports 9 are arranged in a concentric ring shape. Each of the main fuel injection nozzles 8 and each of the tertiary air supply ports 9 is provided with an appropriate inclination so that the main fuel F and the tertiary air A3 are supplied toward the vertically downward auxiliary combustion flame. 10
is the tertiary air supply duct.

The furnace top part 1a and the furnace side wall part 1b of the furnace body 1 have a double wall 1.
C, and is cooled by passing cooling water W inside. A cooling medium injection port 11 for injecting water or steam for cooling toward the tip of the main flame in the furnace body 1 is provided at the lower part of the furnace side wall 1b. Further, the furnace bottom 1d is formed into an inverted conical shape, and a combustion exhaust gas outlet 1e is provided in the center thereof.

In the above-mentioned combustion furnace, the auxiliary fuel f is first supplied to the auxiliary burner 3, and a stable vertically downward auxiliary flame is formed by the primary air A1 which is swirled and supplied by the action of the swirl vane 4a, and the main fuel F Secure an ignition source. Since the secondary air A2 is supplied around this auxiliary combustion flame from the slit-shaped secondary air supply port 6 without swirling in an annular manner, the secondary air A2 is injected from the main fuel injection nozzle 8 disposed on the outer periphery of the secondary air A2. The main fuel F is prevented from entering the auxiliary flame,
Preserves the ash content of main fuel F! This prevents scale from adhering and growing on the inner wall surface of jf&2j2 and the inner wall surface of the furnace top 1a.

The main fuel F injected from the main fuel injection nozzle 8 toward the auxiliary flame is combusted by the secondary air A2 supplied from the inner periphery and the tertiary air A3 supplied from the outer periphery, and the main fuel F is combusted by the furnace main body. A vertically downward main flame is formed at the center of 1. At this time, since the tertiary air A3 is supplied from the outer circumference of the main fuel F toward the main flame, the combustion products are prevented from coming into direct contact with the inner wall surface of the furnace top 1a and the furnace side wall 1b. Even if a fuel containing ash is used as the main fuel F, the ash is prevented from becoming scale and adhering to and growing on the inner wall surface of the furnace top 1a and the furnace side wall 1b. This allows long-term continuous operation.

Further, the above-mentioned combustion furnace includes a furnace top portion 1a of the furnace body 1, a furnace side wall portion 1
b and flame holding 1i2 have a double-walled structure and are water-cooled, so even if combustion products should come into contact with their inner walls, they will be rapidly cooled and turn into solid particles without forming scales and will not be released into the combustion exhaust gas. It is entrained and discharged out of the furnace. Furthermore, if a cooling medium such as water or steam is injected into the tip of the main flame from the cooling medium injection port 11 to rapidly cool the combustion gas to below the melting point of the solid product, scale adhesion near the furnace bottom 1d can be prevented. Moreover, the volume of combustion gas can be reduced, and subsequent combustion gas-related devices can be made more compact.

FIG. 3 shows a combustion furnace according to a second embodiment of the invention.

The combustion furnace of the second embodiment is different from the combustion furnace of the first embodiment shown in FIGS. Instead of arranging a plurality of tubular tertiary air supply ports 9 in two concentric annular rows as secondary air supply ports, the furnace wall of the furnace top 1a is formed with a perforated plate 12, and the perforated plate t2 is A tertiary air supply duct 13 is provided on the back side, and a large number of through holes 1 of the perforated plate 12 are provided.
2a is used as a tertiary air supply port to supply tertiary air into the furnace body 1, and a plurality of cooling water pipes 14 are arranged at appropriate intervals in contact with the back surface of the perforated plate 12, and the main fuel injection nozzle 8 is disposed through the perforated plate 12, and only the furnace side wall 1b is made into a double wall 1C and is water-cooled.Other than that, the combustion furnace has exactly the same structure as the combustion furnace of the first embodiment. are doing.

The combustion furnace of the second embodiment has the above-described structure, and by the same action as the combustion furnace of the first embodiment, the inner wall surfaces of the periphery of the flame-holding tube 2, the furnace top 1a, and the furnace side wall 1b are heated. Combustion products do not adhere or grow as scale, and long-term continuous operation is possible.

Note that a similar configuration can be applied to a combustion furnace in which fuel and combustion air are supplied to the furnace bottom 1d.

Effects of the Invention As described above, even if the combustion furnace of the present invention uses fuel such as pulverized coal containing ash as the main fuel, the combustion products will not adhere and grow as scale on the inner wall surface of the furnace body. It has the special effects of being able to prevent damage, be easy to maintain and manage, and be able to operate continuously for a long period of time.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a combustion furnace according to a first embodiment of the present invention, and a second embodiment of the present invention is shown in FIG.
The drawings are a sectional view taken along the line II in FIG. 1, FIG. 3 is a longitudinal sectional view of a combustion furnace according to a second embodiment of the present invention, and FIG. 4 is a longitudinal sectional view of a conventional combustion furnace. DESCRIPTION OF SYMBOLS 1...Furnace body, 2...Flame stabilizing tube, 3...Assistant burner, 4...Primary air supply port, 6...Secondary air supply port,
8... Main fuel injection nozzle, 9... Tertiary air supply port,
12... Porous plate, 12a... Through hole. Agent Yoshihiro Morimoto Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. An auxiliary combustion burner that injects auxiliary fuel vertically into the furnace to form an auxiliary combustion flame is installed in the vertical furnace body. Combustion characterized by having a secondary air supply port, a secondary air supply port for main fuel combustion, a main fuel injection nozzle forming a main flame, and a tertiary air supply port for main fuel combustion. Furnace.