JPH0820061B2 - Atomizer for slurry fuel - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a slurry fuel atomizer, and more particularly to a slurry fuel atomizer suitable for a boiler that requires improved reliability during boiler combustion operation.

[Conventional technology]

CWM (High Concentration Coal / Water Slurry) is a fluidized fuel, and is characterized in that it can be atomized and burned using an atomizer like conventional oil-based fuels.

FIG. 5 is a sectional view showing an example of a burner gun conventionally used to burn CWM. A small-diameter burner gun inner cylinder 3 and a large-diameter burner gun outer cylinder 4 are arranged coaxially, and the space generated in the gap between the two cylinders is used as the fuel flow path 1, and the inner cylinder 3
The inside is configured as the atomization medium flow path 2. The fuel is supplied to the fuel flow path 1, and the vapor, which is the atomization medium, is supplied to the atomization medium flow path 2 and is sprayed by being simultaneously discharged from each atomization atom and burned.

A burner gun having a structure in which the flow paths 1 and 2 are exchanged as shown in FIG. 6 has also been used conventionally.

The slurry fuel typified by CWM tends to harden when it is excessively heated or the flow stops in the heating field, which is a weak point in burner operation. Especially under the condition that a large temperature gradient exists between the burner root and the atomizer tip facing the furnace, such as a burner, the risk of fuel sticking is considered to be higher than expected. Therefore, sufficient consideration is required for burner operation. This point will be described in detail below.

This kind of fuel sticking trouble can occur from the furnace side when the atomizer is clogged with foreign matter and the fuel flow stops It is predicted that the burner will be heated by the residual heat in the furnace. If the CWM sticks or blocks in the burner gun fuel flow path, disassembling the burner and cleaning / washing it is not easy. In particular, the burner gun for CWM is considerably larger and heavier than the burner gun for oil burning because the calorific value per unit weight of CWM is lower than that of C heavy oil. Therefore, removal, disassembly, and cleaning work become even more difficult. As described above, it takes considerable time and labor to reuse the burner gun, but it is said that it is impossible to reuse the burner gun whose fuel has once adhered. There are nearly 40 burners in a real can, but if all of these are stuck in fuel (in the case of a boiler stop accident, etc.) and all cannot be reused, restarting the boiler is not easy.

For this reason, the occurrence of the above troubles may cause fatal damage to the boiler. Therefore, if an accident occurs, it is necessary to economically reuse and restart the operation as quickly as possible.

[Problems to be solved by the invention]

However, in the conventional burner gun, troubles such as fuel sticking are likely to occur and recovery in a short time is difficult, so that economical reuse and restart may not be achieved.

The object of the present invention is to solve the above-mentioned problems of the conventional technology and to improve the reliability during boiler combustion operation by allowing immediate reuse when a problem such as fuel sticking and blocking in the fuel flow path occurs. The purpose is to provide an atomizer for slurry fuel.

[Means for solving problems]

In order to achieve the above object, the slurry fuel atomizer of the present invention has a thin-walled pipe fitted into the fuel supply passage so that the fuel can flow, and supplies the thin-walled pipe with the fuel when the fuel adheres to the thin-walled pipe. It is characterized in that it can be extracted from the passage.

[Action]

When the fuel adheres to the fuel supply passage, the fuel adheres to the thin-walled tube fitted in the fuel supply passage. When the fuel adheres, the adhered fuel can be removed from the fuel supply passage only by extracting the thin-walled tube from the fuel supply passage. Therefore, it is possible to prevent fuel from sticking or blocking.
Reuse of the burner becomes extremely easy.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

1 and 2 are a front sectional view and a sectional view taken along the line II-II showing an embodiment of the present invention.

An atomizer chip 5 is attached so as to cover the ends of the inner cylinder 3 and the outer cylinder 4. The atomizer tip 5 is fixed to the outer cylinder 4 by a cap nut 6. At this time, on the contact surfaces of the atomizer tip 5 and each of the outer cylinder 4 and the inner cylinder 3,
Packings 7 and 8 are provided. Atomizer chip 5
Inside, there is a mixing injection hole 9 for spraying fuel into the boiler.
And a fuel supply hole 10 that communicates with the mixing ejection hole 9 and the fuel flow path 1. Further, the atomizer chip 5 is provided with the atomizing medium supply hole 11 which communicates with the atomizing medium flow path 2 and the mixing jet hole 9.

Further, a thin-walled pipe 14 is arranged on the inner peripheral surface of the flow path 1, and a thin-walled pipe 15 is arranged on the outer peripheral surface thereof. The thin tube 14 is the inner cylinder 3
The outer diameter of the thin tube 15 is slightly larger than the outer diameter of the outer tube 4, and the thin wall tube 15 is slightly smaller than the inner diameter of the outer tube 4. Fuel 12 is fed into the annular space formed by thin tubes 14 and 15. The thin tubes 14 and 15 are arranged so that they can be freely attached to and detached from the burner gun body.

3 and 4 are a front sectional view and a sectional view taken along the line IV-IV showing another embodiment of the present invention. The present embodiment is an example of an internal mixing type (the above-mentioned examples are intermediate mixing type), and the same reference numerals are used for the same ones (or those having the same function) as in FIG. 1 and FIG. Therefore, redundant description will be omitted. In FIGS. 3 and 4, a mixing chamber is provided inside.
An atomizer chip 16 having 21 is arranged at the tip portion, and an intermediate plate 17 and an atomizer head 18 are arranged in a laminated state between the atomizer chip 16 and the inner cylinders 3 and 4. Further, a thin-walled tube 20 is arranged near the inner peripheral surface of the inner cylinder 3.

The atomizer chip 16 has a spout hole 19 on the head, and is a mixing chamber.
The mixed fuel in 21 is ejected. Further, the intermediate plate 17 is provided with the fuel 12 supplied through the thin tube 20 and the atomization medium 13 supplied from the gap between the inner cylinder 3 and the outer cylinder 4.
It has the function of premixing and.

It should be noted that in any of the above-mentioned embodiments, it is not necessary to fix the thin-walled tubes 14, 15 and 20 to the adjacent members. Also, the length of the thin wall tube should be the same length as the inner cylinder and the outer cylinder, but since the solidification of fuel is started from the atomizer tip side, as long as the downstream tip is fixed to the atomizer tip part. , It doesn't matter even if it's short.

Next, the function and effect of the slurry fuel atomizer configured as described above will be described.

In the configuration of FIG. 1, the fuel 12 is supplied to the fuel supply hole 10 via the fuel passage formed by the thin tubes 14 and 15. At the same time, the atomization medium 13 is supplied to the atomization medium supply hole 11 via the flow path 2 and mixed with the fuel 12 in the mixing injection hole 9. The mixed slurry fuel is sprayed from the tip of the mixing ejection hole 9.

In such a configuration, if the flow of the fuel stops in the fuel supply pipe for some reason, the fuel sticks in the flow passage, and in the worst case, the fuel is blocked. In this case, it is possible to immediately restart the operation by replacing the thin-walled tubes 14 and 15.

On the other hand, in the configuration of FIG. 3, the fuel 12 supplied from the thin-walled tube 20 and the atomizing medium 13 supplied from the flow path 2 are primarily mixed by the intermediate plate 17. In the mixing chamber 21, sufficient mixing is performed.
The mixed slurry fuel is sprayed from the ejection holes 19. Even in this case, if the fuel 12 is stuck in the thin-walled pipe 20 and is clogged, the thin-walled pipe 20 can be replaced to restart immediately.

Since the thin tubes 14, 15 and 20 can be made of inexpensive materials (tinplate, galvanized iron, etc.) and do not require processing cost, they can be disposable.

Further, in the configuration of FIG. 1, the inner cylinder 3 and the thin-walled pipe 14
A thin air layer is formed between the inner cylinder and the thin-walled tube 20 between the inner cylinder and the thin-walled tube 20. Therefore, this air layer lowers the heat transmission coefficient and produces a kind of adiabatic effect. By preventing heat exchange between the CWM and the steam (usually saturated steam) that is the atomizing medium, the amount of condensation (drain) of the steam can be reduced. If the steam does not agglomerate, the following actions and effects can be obtained.

(I) The vapor pressure does not decrease, and normal gas-liquid ratio conditions can be maintained. Therefore, combustion does not deteriorate.

(Ii) Drain does not mix into the CWM at the atomizer ejection port. That is, the concentration of CWM does not decrease.

(Iii) Vibration on the steam side can be prevented by condensation. That is, the pulsation of the spray flow is reduced and the flame can be stably maintained.

In addition, since a heat insulating effect is produced by using the thin-walled tube, the following effects can be obtained.

(1) Stable ignition and improved flame holding property.

(2) In connection with the promotion of ignition, unburned content in ash is reduced, and thus combustion efficiency is improved.

(3) The boiler furnace can be made smaller because the flame is shortened. Therefore, it is advantageous from the economical aspect.

(4) Due to the effects of (1) and (2), it is also advantageous for combustion of slurry fuel using high fuel ratio coal (fuel ratio = fixed carbon / volatile matter) having inferior combustibility.

(5) Due to the effect of (1), a stable high-temperature reduction zone is formed near the burner, and NOx can be reduced.

(6) The amount of atomizing medium (vapor) can be reduced. Therefore, the boiler efficiency is increased and the auxiliary equipment power cost is reduced.

(7) Low excess air combustion becomes possible. Therefore, it is possible to prevent the low temperature corrosion action even when using a carbon type having a high S (sulfur) content.

As described above, implementing the present invention is extremely effective not only for improving boiler operability but also for energy saving and environmental conservation measures.

The burner gun to which the present invention is applied can be applied not only to CWM specifically taken as an example in this section but also to so-called slurry fuel in which finely divided solids as described below are suspended in a liquid.

(1) Pitch / Water Slurry (2) Oil Coke / Water Slurry (3) Coal / Methanol Slurry (4) COM (Coal / Heavy Oil Mixed Fuel) (5) Inferior Residue On the other hand, even fuels such as light oil and heavy oil, slurry fuel Although the problem of sticking and clogging is less so, it is considered that if it is excessively heated in the fuel flow path, carbon is deposited and adversely affects combustion. Therefore, the burner gun structure according to the present invention can also be applied to an oil-fired boiler combustor.

〔The invention's effect〕

As described above, according to the present invention, the replaceable thin-walled tube is arranged in the fuel supply passage, and the thin-walled tube is replaced when the fuel is stuck and blocked, so that the burner is immediately restarted. , The boiler efficiency can be increased. Furthermore, the burner gun can be reused, and the work of replacing (disassembling, cleaning, and assembling) the burner gun can be shortened.

[Brief description of drawings]

1 and 2 are front sectional views and sectional views taken along the line II-II showing one embodiment of the present invention, and FIGS. 3 and 4 are front sectional views and IV showing another embodiment of the present invention. -IV arrow sectional view, FIG. 5 is a sectional view showing an example of a conventional burner application, FIG.
The figure is a sectional view showing an example of another conventional burner gun. 1 ... Fuel flow path, 2 ... Atomization medium flow path, 3 ... Burner gun inner cylinder, 4 ... Burner gun outer cylinder, 5, 16 ... Atomizer tip, 9 ... Mixing ejection hole, 10 ... Fuel supply Hole, 11 ...
… Atomization medium supply hole, 14, 15, 20 …… Thin-walled tube, 17 …… Intermediate plate, 18 …… Atomizer head,
19 ... Spout hole.

Claims (3)

[Claims] 1. A fuel and atomizing medium supplied through a fuel supply passage of a burner gun, and a reduced diameter fuel supply hole of an atomizer member detachably provided at an end of the fuel supply passage. In an atomizer that mixes and sprays the mixed flow to the outside from the ejection hole, a thin-walled pipe is fitted into the fuel supply passage so that the fuel can flow, and the thin-walled pipe is fixed when the fuel is fixed in the thin-walled pipe. An atomizer for slurry fuel, characterized in that it can be extracted from the fuel supply passage. 2. The fuel supply passage is configured by using an internal space of a burner gun inner cylinder, and a single thin-walled pipe having a diameter smaller than an inner diameter of the inner cylinder is fitted in the burner gun inner cylinder. The atomizer for slurry fuel according to claim (1). 3. The fuel supply passage is formed by using a gap between a burner gun inner cylinder and a burner gun outer cylinder,
The slurry fuel atomizer according to claim (1), wherein thin-walled pipes are fitted in an outer peripheral portion of the burner gun inner cylinder and an inner peripheral portion of the burner gun outer cylinder, respectively.