JPS59150213A - Method for atomization of pulverized coal-water slurry and burner thereof - Google Patents

Abstract

PURPOSE:To prevent the blocking of the pathway of CWM in atomizing CWM by keeping the pressure of the pulverized coal-water slurry in the slurry pathway higher than the saturated pressure of water corresponding to the temperature of an atomizing medium. CONSTITUTION:CWM1 is passed through CWM pathway 5 and jetted from CWM jet nozzle 8 into an atomizing chamber 9. On the other hand, steam 2 as an atomizing medium heated to about 200 deg.C usually is passed through an atomizing medium pathway 7, and jetted from an atomizing medium jet nozzle 11 into the atomizing chamber 9 while rotationally flowing down, where CWM jetted is atomized. The atomized CWM is mixed with combustion air 13 flowing outside of an outer cylinder 3 and then burned. The heating of an inner cylinder 4 is suppressed because of its heat-insulating structure and thereby the saturated pressure of water in CWM can be relatively lowered by the pressure of CWM. The blocking of the CWM pathway, etc., in atomizing CWM can thus be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for atomizing a pulverized coal-water slurry and an atomizing burner, and more particularly to an atomizing method and a burner suitable for preventing blockage of a pulverized coal-water slurry passage.

In recent years, as energy sources have become more diversified, coal has been increasingly used as fuel for combustion devices such as commercial boilers.

Various coal combustion methods have been known for a long time, and one of them is a method in which pulverized coal is made into a syssurarium by adding water instead of using liquid fuel such as heavy oil (hereinafter referred to as CWM).
Combustion methods that use According to this combustion method, conventional oil-fired combustion equipment equipped with a medium spray burner can be applied as is without any special equipment changes, and there are other advantages such as no need to use liquid fuel such as heavy oil. be.

However, the conventional media atomization burner has a fuel passage and an atomized medium passage, and the space between them is simply made of a metal wall, so if this burner is applied as is for CWM It was found that various troubles such as those described below occur. That is, one of them is that the moisture in the CWM evaporates from the passage wall surface due to heat transfer from the atomization medium, so that the coal content in the CWM gradually solidifies from the wall surface and eventually blocks the passage. It is. Further, the nozzle tip is heated by flame radiation in the furnace, and in this case as well, there is a problem that the CWM nozzle or atomization chamber in the nozzle tip is clogged for the same reason as above. In order to solve the problem of CWM continuous supply due to the above blockage, CWM
It is possible to reduce the viscosity by lowering the concentration of pulverized coal in the coal, but in this case, the amount of heat released into the atmosphere due to flue gas increases, resulting in a decrease in the thermal efficiency of the entire plant. . Also, if we try to lower the viscosity of CWM,
The pulverized coal in the CWM is more likely to settle and may be partially assimilated to block the CWM passage. Furthermore, as mentioned above, on the high concentration side of pulverized coal, there is a limit due to solidification that progresses from the wall surface, and on the other hand, on the low viscosity side, there is a limit on solidification due to sedimentation of pulverized coal, so the pulverized coal concentration for practical CWM There is a problem that the range is narrow and therefore concentration control becomes extremely difficult.

SUMMARY OF THE INVENTION An object of the present invention is to provide a CWM atomization method and a method for preventing clogging of CWM passages during CWM atomization.

We maintain the pressure of the CWM in the CWM passage higher than the saturation pressure of water, which corresponds to the temperature of the atomizing medium, and
Preventing the water contained in WM from boiling K, 9, CW
In order to avoid blockage in the M passage and to prevent boiling, the temperature of the CWM should be kept low, and the saturation pressure of water should be lowered to make the pressure of the CWM relative to the saturation pressure of water. I found out that I could improve it.

The present invention provides a method for atomizing a pulverized coal-water slurry in which a pulverized coal-water slurry and an atomizing medium are made to flow into an atomization chamber from separate passages to atomize the slurry. It is characterized in that the pressure of the slurry in the passage is maintained higher than the saturation pressure of water, which corresponds to the temperature of the atomizing medium.

Further, the burner used in the present invention is a CWM atomizing burner including a CWM passage and an atomized medium passage.
The present invention is characterized in that a means for preventing boiling of the water contained in the CWMK sent through the passage is provided.

In order to maintain the above CWM pressure high, it is sufficient to increase the supply flow rate by 10 WM against the flow resistance of the CWM mouth, but the flow rate cannot be increased at low loads when the CWM flow rate decreases, so the flow rate is increased. In addition, keep the CWM pressure high,
A means is required to prevent boiling of the water containing the CWM.

As the water boiling prevention means, those capable of preventing the temperature rise of the CWM are widely applied, such as a heat insulating structure provided on the peripheral wall surrounding the CWM passage, a heat insulating structure provided in the nozzle tip at the tip of the burner, Also, i=a combination of these, etc. can be shown. The above-mentioned heat insulating structure may be one in which independent or continuous hollow chambers are provided in the metal base material of the picture part, or the corresponding part may be made of a non-metallic material with poor thermal conductivity. In addition, when the above-mentioned communicating hollow chamber is provided, it is also possible to introduce a cooling medium into the chamber from the outside to perform forced cooling.

Hereinafter, the present invention will be explained in more detail with reference to embodiments shown in the drawings.

FIG. 1 is a sectional view of a CWM atomizing burner showing one embodiment of the present invention. This burner device includes an inner cylinder 4 provided at the center forming a CWM passage 5, and an annular passage 7 for an atomizing medium (for example, steam) provided between the outer periphery of the inner cylinder 4 and the outer periphery of the inner cylinder 4. an outer cylinder 3 forming a CWM passage 5;
A CWM nozzle 8 provided at the furnace side tip of the atomizing medium passage 7, and usually a plurality of atomizing medium nozzles 10 provided at the furnace side tip of the atomizing medium passage 7;
It mainly consists of an atomization chamber 9 that communicates with Independent heat insulating hollow chambers 6 are successively walled along the burner axis to form a heat insulating structure.

In the apparatus configured as described above, CWMI passes through the CWM passage 5 and is then ejected from the CWM nozzle 8 into the atomization chamber 9. On the other hand, the steam 2, which is an example of an atomizing medium whose temperature is normally raised to about 200°C, passes through the atomizing medium passage 5 and then passes through the atomizing medium nozzle 10.
The C after the above ejection is ejected into the atomization chamber 9 under a swirling flow.
Atomize the WM. The atomized CWM is mixed with combustion air 13 flowing outside the outer cylinder 3 and then combusted. The combustion air 13 is generally at a temperature of 300 to 350°C to improve combustion.
It is often preheated to

CWMI refers to the steam 2 flowing through the atomizing medium passage 7 and the combustion air 1 flowing outside the outer cylinder 3 while passing through the CWM passage 5.
3 is in an environment where it is easy to receive υ heating, but by making the inner cylinder 4 a heat insulating structure as described above, heating is suppressed.
This is K, 9. Since the saturation pressure of water in the CWM can be made relatively lower than the CWM pressure, the water in the CWM does not boil even during low load operation, and therefore the lime content will no longer solidify and block the passage.

Next, FIG. 2 shows another embodiment of a burner device according to another embodiment of the present invention, in which the outer cylinder 3A is also formed of a heat insulating structure having the same structure as the inner cylinder 4 of FIG. Other than that, the configuration is the same as that in FIG. 1.

In this case, the passage within the inner cylinder 4 serves as the atomizing medium passage 7, while the annular passage formed between the outer periphery of the inner cylinder 4 and the inner periphery of the outer cylinder 3A serves as the CWM passage 5.

Also in the device having such a configuration, heating of the CWM can be suppressed and the effect of preventing blockage of the CWM passage can be obtained, as in the case of the embodiment shown in FIG.

Furthermore, FIG. 3 shows a nozzle tip portion of a device according to another embodiment of the present invention, which has an independent hollow chamber 61 at the tip end on the furnace side perpendicular to the burner axis, and a CWM nozzle 8.
The structure is similar to that of the nozzle chip 11 shown in FIG. 1, except that an independent hollow chamber 62 is provided on the outer periphery of the nozzle chip 11 to provide a heat insulating structure.

With this configuration, it is possible to suppress flame radiation in the furnace and heating by the atomizing medium passing through the passage 7, so that C
In addition to preventing blockage of the WM passage, it is also possible to prevent blockage of the CWM nozzle 8 and the atomization chamber 9.

Although typical embodiments of the present invention have been described above, the present invention is of course not limited to these. For example, a heat insulating material may be inserted into the hollow chamber 6 of the embodiment shown in FIG. By doing so, the heat insulation effect can be further improved. Further, the hollow chamber may have a communicating structure, in which case a cooling medium can be forcibly injected from the outside to provide a cooling effect.

The communicating hollow chamber described above can also be communicated with the hollow chamber of the nozzle chip shown in FIG. 3, and a cooling medium can be forcibly injected from the outside into the entire communicating chamber thus obtained to further enhance the cooling effect. It can also be improved. Furthermore, the same effect can be obtained by using a nozzle chip made entirely of a non-metallic material with low thermal conductivity in place of the nozzle chip shown in FIG.

Furthermore, the present invention is not limited to the type of burner (two-fluid burner) shown in each embodiment, but is widely applicable to known medium spray type burners.

As described above, according to the present invention, the CWM sent through the CWM path
The pressure of CWM should be made higher than the saturation pressure of water at the temperature of the atomizing medium, or a means for preventing boiling of water containing 0 wM should be provided for this purpose. This makes it possible to solve the problem of solidification and blockage, which can prevent CWM combustion from clogging even during low-load operation when water boils easily. It can be done with high efficiency.

[Brief explanation of drawings]

FIG. 1 is a side sectional view of a CWM atomizing burner according to an embodiment of the present invention, and FIG. 2 is a side sectional view showing a cylindrical portion of a CWM atomizing burner according to another embodiment of the present invention. FIG. 3 is a side sectional view showing a nozzle tip portion of a CWM atomizing burner according to another embodiment of the present invention. 1... CWM, 2... Atomization medium, 3.3 Person... Outer cylinder, 4... Inner cylinder, 5... CWM passage, 6.61.6
2...Hollow chamber, 7...Atomization medium passage, 8...CW
M nozzle, 9... Atomization chamber, 1o... Atomization medium nozzle, 1
1. Tuzzle cap, 13. -- Combustion air. Agent Patent Attorney Takeshi Kawakita

Claims (4)

[Claims] (1) In a pulverized coal-water slurry atomization method in which a pulverized coal-water slurry and an atomizing medium are collided and merged with atomized water from separate passages to atomize the slurry, in the pulverized coal-water slurry passage. A method for atomizing a pulverized coal-water slurry, characterized in that the pressure of the slurry is maintained higher than the saturation pressure of water corresponding to the temperature of the atomizing medium. (2) In a pulverized coal-water slurry atomizing burner equipped with a pulverized coal-water slurry passage and an atomizing medium passage, means for preventing boiling of the water contained in the imitation pulverized coal-water slurry sent into the passage is provided. An atomizing burner for pulverized coal-water slurry, characterized by the following: (3) In claim 1, the water boiling prevention means is provided on a peripheral wall surrounding the pulverized coal-water slurry passage.
'Also, an atomizing burner for pulverized coal-water slurry, characterized by having a heat insulating structure. (4) In claim 1, the water boiling prevention means is a heat insulating structure provided on the peripheral wall surrounding the pulverized coal-water slurry passage and the nozzle tip at the tip of the burner. Atomization burner for pulverized coal-water slurry.