JPH0151732B2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field This invention relates to coal, water, slurry (hereinafter referred to as CWS).
This relates to combustion burners that use slurry fuel, such as those typified by

Conventional technology CWS is supplied under pressure to a boiler burner using a pump or the like, and like liquid fuel, it can be atomized with steam or air as an atomizing gas and then combusted.

However, since CWS contains a large amount of pulverized coal and is manufactured using water as a solvent (coal concentration 60-70%, therefore water content 40-30%) and additives, it has the following disadvantages: be.

(1) Due to the high viscosity and strong cohesive force between atomized coal particles, it is difficult to atomize, and the average particle size of CWS droplets is 100 to 300 μm, while the average particle size of atomized coal particles is 40 to 60 μm. Larger compared to
CWS droplets burn as they gather, making it difficult for them to burn completely.

(2) Since it contains 40 to 30% water, a water evaporation process is required before the coal particles contained in the atomized CWS droplets can ignite and burn. As a result, the ignition point is unstable, making it difficult to maintain a stable flame, reducing combustion efficiency and causing breathless combustion or misfire.

Figure 2 shows an example of a conventional CWS burner.
The CWS sprayed from the atomizer 2 provided at the tip of the CWS burner gun 1 is the primary air 5 supplied from the primary air passage 3 and the secondary air passage 4, respectively.
In order to maintain this ignition and flame, the secondary air needs a strong swirling flow. Therefore, it is designed to pull in the ignition point 9 and maintain ignition.

Problems to be Solved by the Invention However, in such a CWS, it is extremely difficult to maintain ignition because the CWS contains 30 to 40% water, and it is not practical to stabilize ignition point 9 and flame 10. There were also problems in obtaining stable ignition and good combustion due to uneven supply of primary air and burnout of the flame stabilizing plate 7.

This invention solves the above-mentioned problems in CWS combustion, namely, that CWS droplets are difficult to atomize due to the strong cohesive force between coal particles, coal particles burn while aggregated, and moisture evaporates prior to combustion. Because CWS requires a process, it is difficult to obtain stable ignition and flame, the combustion efficiency is low, and stable continuous operation is difficult. It is something to measure.

Means for Solving Problems The present invention aims to obtain stable ignition and flame by bringing the ignition point of CWS containing a large amount of water closer to the flame stabilizer. An atomizer 12 for spraying slurry fuel is provided at the tip of the burner gun 11, a flame stabilizer 13 is provided on the outer periphery of the tip of the burner gun, a primary air passage 14 is communicated with the flame stabilizer, and the primary air passage is connected to the flame stabilizer 13. The present invention is a slurry fuel combustion burner having a secondary air passage 15 on its outer periphery, and in which the flame stabilizer 13 is made of a ceramic porous body.

Function: The CWS is atomized by the atomizer 12, the primary air 18 from the primary air passage 14 passes through the flame stabilizer 13, and is supplied toward the ignition part of the CWS spray stream, and from the secondary air passage 15. The secondary air 19 is supplied as a swirling flow toward the flame 20 from the secondary air supply port 17 on the outer periphery of the flame stabilizer.

Due to this swirling flow of secondary air, a negative pressure portion is formed near the front of the flame stabilizer 13.

Further, the flame stabilizer 13 is made of a porous ceramic body, and is heated to a high temperature due to the heat radiated from the flame 20.

Therefore, from the atomizer 12
The CWS is efficiently sprayed into the negative pressure area, and when the primary air 18 from the primary air passage 14 passes through the flame stabilizer 13, it absorbs heat from the flame stabilizer and is rectified in a high temperature state to form the CWS spray. It will be supplied towards the current.

A portion of this CWS spray flow and the primary air are vigorously stirred and mixed in the negative pressure section to form an ignition section.

At this time, a part of the radiation heat obtained by the flame holder from the flame is supplied from the flame holder to the ignition section.
Promotes the evaporation of water in CWS.

Therefore, the flame holder 13 acts as if it were an ignition point, and a flame is formed from the flame holder.

Embodiment A CWS burner gun 11 has an atomizer 12 at its tip and is held by a housing tube 21. Around the housing tube 21 are primary air passages 14 and 2 for primary air 18.
A secondary air passage 15 for secondary air 19 is arranged, and the secondary air 15 is given a swirl by a swirler or the like and is ejected from the secondary air supply port 17 .

A flame stabilizer 13 made of porous ceramic material is disposed around the outer periphery of the tip of the housing tube 21. The flame stabilizer 13 has a porosity of 65 to 80%, and 1
It has the role of uniformly supplying the secondary air to the ignition section 22 and heating it. Also, this flame holder 13
is inserted into the housing tube 21 and the mounting spring 2
3 and is pressed and fixed by the flame stabilizer 13.
The outer peripheral surface 16 forms the inner peripheral surface of the secondary air supply port 17.

In addition, a heat radiator 2 is placed around the flame stabilizer 13.
4 is placed at the end of the secondary air passage 15, and this radiator 24 is made of refractory material or ceramic.

Due to the swirling flow 25 of the secondary air, a negative pressure area is formed near the front of the flame stabilizer 13, resulting in a stable vortex flow 2.
6 occurs. A part of the CWS spray flow from the atomizer 12 and the primary air from the flame holder 13 are vigorously stirred and mixed by this vortex flow and ignited, and a stable ignition part 22 is obtained from the front of the flame holder 13. It will be done.

At this time, the primary air required for the ignition part is heated to a high temperature while passing through the flame holder, and the transfer of radiant heat between the flame and the front of the flame holder promotes moisture evaporation in the ignition part and stabilizes the ignition. is further maintained.

In addition, the CWS spray stream is stirred and mixed by the swirling flow 25 of secondary air, and the radiant heat radiator 24 applies radiant heat from the flame to the CWS spray stream, promoting the evaporation of moisture, which not only ignites the flame but also ignites it. It also provides stability.

Note that 27 indicates a primary air inlet, and 28 indicates a secondary air inlet.

Effects of the Invention This invention provides an atomizer for spraying slurry fuel at the tip of a burner gun, a flame holder is provided around the outer periphery of the tip of the burner gun, a primary air passage is communicated with the flame holder, and the primary air passage The burner has a secondary air passage around the outer periphery of the burner, and the flame stabilizer is made of porous ceramic material, so the flame stabilizer utilizes the radiant heat of the flame to sufficiently preheat the primary air. Since the evaporation of water in the CWS is promoted to the maximum, stable ignition and flame can be obtained from the front of the flame holder when burning the CWS, and good combustion can be maintained without the problem of burnout of the flame holder. Ru. Therefore, when applied to boilers etc., high combustion efficiency can be obtained.

Furthermore, by making the outer circumferential surface 16 of the flame stabilizer the inner circumferential surface of the secondary air supply port, the secondary air is also sufficiently preheated, which helps improve combustion efficiency, and the outer circumferential surface 16 is free from thermal expansion. In this state, the strain due to the difference in coefficient of thermal expansion between the steel plate composing the primary air passage 14 and the ceramic porous body is released on the outer circumferential surface 16, and the ceramic porous body composing the flame stabilizer 13 is Attachment of the porous body becomes extremely easy.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an embodiment of a burner according to the present invention, and FIG. 2 is a sectional view of a conventional example. 11...Burnagan, 12...Atomizer,
13...flame holder, 14...primary air passage, 15...
...Secondary air passage, 17...Secondary air supply port.

Claims (1)

[Claims] 1. An atomizer for spraying slurry fuel is provided at the tip of the burner gun, a flame holder is provided around the outer periphery of the tip of the burner gun, a primary air passage is communicated with the flame holder, and the primary air passage 1. A slurry fuel combustion burner having a secondary air passage provided on the outer periphery of the burner, wherein the flame stabilizer is made of a porous ceramic body. 2. The slurry fuel combustion burner according to claim 1, wherein the outer circumferential surface of the flame stabilizer is the inner circumferential surface of the secondary air supply port.