JPS5811308A - Pulverized coal combustion burner - Google Patents

Abstract

PURPOSE:To provide a pulverized coal combustion burner having improved heat and abrasion resistance, by installing a ceramic component in a duct for supplying pulverized coal. CONSTITUTION:A combustion burner B is composed of a coaxial and double pipe structure; a pulverized coal supply duct 5 is formed between an inner wall 3 of an external pulverized coal supply duct 1 and an outer wall 4 of an internal air supply duct 2, and a conveying duct 7 for sending pulverized coal together with air into a burner B is connected with the rear edge of the pulverized coal supply duct 5. Then, heat and abrasive resisting ceramic components 11 and 12 are installed in the vicinity of a supply opening 10 for a mixed fluid consisting of the air in a pulverized coal supply duct 5 with which the conveying duct 7 is connected and the pulverized coal and in the vicinity of a jet 8 of the edge of the burner B respectively. Thus, durability of the burner can be improved as the burner can be prevented from abrasion by the pulverized coal and thermal influence thereto can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pulverized coal combustion burner, and more particularly to a pulverized coal combustion burner with improved heat resistance and wear resistance.・'-Same It is believed that most of the wear of pulverized coal combustion burners is caused by the pulverized coal particles colliding with the inner wall of the burner, causing cracks in the cutting process. The factors include the hardness of the pulverized coal particles, particle diameter, particle shape, particle collision speed, particle collision amount, particle concentration, and collision angle with the burner wall surface.

The degree of carbonization of steam coal used for pulverized coal combustion is approximately 80 to 85.
%, which means that it has the highest hardness among the types of coal. Further, the average particle size is generally about 50 x 10 m, and cannot be made any smaller due to grinding equipment and cost considerations. Furthermore, the means for supplying the pulverized coal to the burner often relies on air, and the flow rate is generally set at 20 g/s or more in order to prevent the accumulation of pulverized coal or the explosion of coal dust.

Therefore, the degree of wear on the burner mainly depends on the amount of pulverized coal supplied, and when combustion is performed to obtain a high amount of heat, the degree of wear increases as the KFi increases.

As shown in Fig. 1, this type of pulverized coal combustion burner has a double pipe structure in which an air supply pipe 2 of a smaller diameter is provided inside a large diameter pulverized coal supply pipe 1. A pulverized coal supply path 5 is defined in which a mixed fluid of pulverized coal and air for pulverized coal supply flows between the inner wall 3 of the pulverized coal supply pipe 1 and the outer wall 4 of the air supply pipe 2, and the inside of the air supply pipe 2 is for burning −
It is configured as an air supply path 6 through which air flows. Further, a transport pipe 7 for guiding the mixed fluid to the pulverized coal supply path 5 is connected to the rear end of the pulverized coal supply pipe 10 from diagonally above. As shown in FIG. 2, this transport pipe 7 is connected to a position offset from the center of the burner B, and as a result, the mixed fluid is guided to the pulverized coal supply path 5 while swirling, so that the pulverized coal particles and Mixing with supply air is facilitated.

On the other hand, near the ejection port 8 of the burner B, the inner wall 813 of the pulverized coal supply pipe 1 and the outer wall 4 of the air supply pipe 2 are formed to be more raised than other parts, and the pulverized coal supply path 5 is formed in a convergent shape. . As mentioned above, the average particle size of pulverized coal is (
Capital) It is about Since it is necessary to increase the relative velocity of the pulverized coal particles in order to increase the combustion speed, the pulverized coal supply path 5 near the burner outlet 8 must be formed narrower than other parts. In addition, near this spout 8,
A holding member 9 that holds the pulverized coal supply path 5 at a constant width is interposed between the inner wall 3 of the pulverized coal supply pipe 1 and the outer wall 4 of the air supply pipe 2.

However, in the conventional general pulverized coal combustion burner B configured as described above, the transport pipe 7 is connected, and the circumference near the rear end of the pulverized coal supply path 5 is rotated at a flow rate of 20@/S or more. As a result of multiple collisions of pulverized coal particles in the mixed fluid introduced as a flow, the inner wall 3 around the rear end part
And the outer wall 4 is easily worn out. On the other hand, since the pulverized coal supply path 5 is narrow in the vicinity of the ejection port 8 of the burner B, the amount of pulverized coal particles colliding with the inner surface of the pulverized coal supply path 5 is large, and in this area, the pulverized coal Since the particle velocity also increases, the inner wall 3 of the pulverized coal supply pipe 1 and the outer 114 portion of the air supply pipe 2 in the vicinity of the spout 8 become more abrasive, as already indicated by the reference numerals in FIGS. 1 and 3. . In particular, the area near the ejection port 8 reaches a high temperature of the pinion 9 due to radiant heat from the large pulverized coal combustion flame, so the tip of the burner B deteriorates, wear resistance decreases, and wear becomes more severe. Furthermore, the holding member 9 interposed between the inner wall 3 and the outer wall 4 also naturally undergoes severe wear.

As described above, conventional pulverized coal combustion burners are made of steel that has been subjected to a general dihard facing process, which makes it impossible to prevent wear due to the material, which shortens the lifespan of the burner9. In addition, due to wear, the cross-sectional area of the spout of the powder coal supply path of the paper machine becomes large.9 The flow rate of the mixed fluid decreases.
In addition to the problem that the combustion effect is reduced, there is also the problem that it takes time to repair worn parts.

The present invention has been made based on the above-mentioned viewpoints, and its purpose is to provide a pulverized coal combustion burner that is subject to severe collisions by a mixed fluid of pulverized coal in a portion of the pulverized coal combustion burner that is susceptible to wear, that is, in the pulverized coal supply path. By providing a ceramic member in the part, it is possible to eliminate the above-mentioned conventional drawbacks and improve the combustion efficiency of pulverized coal, as well as to withstand long-term use.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below based on embodiments shown in the accompanying drawings, which provide an I-pulverized coal combustion burner that can be easily repaired.

4 to 6 show one embodiment of the present invention.

The combustion burner B in this embodiment has a coaxial double pipe structure 9, as in the previous embodiment, and has a space between the inner wall 3 of the outer pulverized coal supply pipe 1 and the outer wall 4 of the inner air supply pipe 2. A pulverized coal supply path 5 is formed, and a transport pipe 7 for feeding the pulverized coal into the burner B together with supply air is connected to the rear end of the pulverized coal supply path 5. Heat-resistant and wear-resistant ceramic members 11 and 12 are installed in the vicinity of the mixed fluid supply port 10 consisting of air and pulverized coal in the pulverized coal supply path 5 to which the transport pipe 7 is connected, and in the vicinity of the jet outlet 8 at the tip of the burner B, respectively. It is installed.

11 ceramic members attached near the mixed fluid supply port 10; furthermore, an inner wall protection ceramic member 11a attached to the circumferential surface of the inner wall 3 of the pulverized coal supply pipe 1; and an air supply pipe 2.
and an outer wall protection ceramic member 11b attached to the outer wall 4 circumferential surface of the inner wall 113 and outer wall 8i! It consists of a cylindrical body that is closely attached along four circumferential surfaces.

The ceramic member 11a for protecting the inner wall can be easily installed by, for example, bolts 13 inserted from the outer wall of the pulverized coal supply pipe 1, and the ceramic member 11b for protecting the outer wall can be mounted by attaching its tip to the air supply pipe 2. It is fixed to a fixed seat 14 formed protruding from a part of the outer wall 4 of
This can be easily done by fixing with the fixing piece 15 inserted from behind the CI. Incidentally, when the ceramic members 11a and 11b are to be removed for repair or inspection, this can be easily done by removing the bolts 13 and the fixing piece 15.

By installing the inner wall protection ceramic member 11a and the outer wall protection ceramic member 11b as described above,
Since the pulverized coal supplied through the transport pipe T hits the ceramic members 11g and 11b near the mixed fluid supply port 10, wear of the burner B can be prevented. For example, when two ceramic members 11a and 11b with alumina purity of 99% and a wall thickness of 10 mm are used, continuous use of the parts can be approximately 20,000 hours, and the conventional steel plate Novana is replaced by Hard 7 Acing. In the case of processing, it took about 4000 hours. The durability time can be significantly improved compared to the previous one.

On the other hand, the ceramic member 1 attached near the spout 8
Similar to the ceramic member 11, 2 further includes a cylindrical inner wall protection ceramic member 12a attached to the inner wall 3 of the pulverized coal supply pipe 1 and a cylindrical outer wall protection ceramic member 12a attached to the outer wall 4 circumferential surface of the air supply pipe 2. The ceramic member 12b is composed of a ceramic member 12b, but in order to increase the flow rate of the mixed fluid containing pulverized coal, the middle part is inclined toward the tip, and the first half is thicker than the second half. The pulverized coal supply path 5 is shaped like a nozzle.

Further, a holding member 16 is integrally formed in the front part of the inner wall protecting ceramic member 12a and is interposed between the outer wall a14 of the air supply pipe 2 and holds the pulverized coal supply passage 5 at a constant width. .

These ceramic members 12a and 12b are inserted from the ejection port 8 side of burner B, respectively, and are inserted into the pulverized coal supply pipe with their rear ends locked in locking steps 17 and 18 formed on the inner wall 3 and outer wall 4. 1 and from the inside of the air supply pipe 2, respectively, to the wall surface by means of ports 19 and 20.

By installing the ceramic member 12m for protecting the inner wall and the ceramic member 12b for protecting the outer wall near the tip of the burner B in this way, the mixed fluid moving in the pulverized coal supply path 5 can be transferred to the ceramic members 12m, 12b.
K hits hard, but these ceramic members 12a,
Since 12b is abrasion resistant, its wear is small. In addition, deterioration of the material due to the influence of radiant heat from the flame can also occur in ceramic components 1.
This can be prevented by the high heat resistance of 28 and 12b. For example, if the ceramic members 12a and 12b of d1 are made of 99% alumina and have a front thick part with a wall thickness of 15 fins, the continuous use time of the part is about 16
000 hours, and when used with silicon carbide ceramic (thickness 101111), which is harder than the above ceramics, it can be used continuously for about 20,000 hours, compared to about 4,000 hours with conventional hard facing processing. The durability can be significantly improved compared to the previous one.

In addition, the above ceramic members 12a and 12b are repaired,
Or, when detaching from burner B for inspection, fix bolt 19. This can be easily done by removing the addition.

FIGS. 7 and 8 show other embodiments of the tip of the pulverized coal combustion burner according to the present invention, and the tip of the burner B is provided with a pulverized coal supply pipe 1 and an air supply pipe 2 that are approximately the same. - diameter cylindrical ceramic members 21a and 21b are respectively attached. These cylindrical ceramic members 21a,
21b is the front half of the outer cylindrical ceramic member 21a and the inner cylindrical ceramic member 21, as in the previous embodiment.
The front half portions b are formed thicker toward the opposing surfaces, and are formed narrower than the diameter of the pulverized coal supply path 5 of the burner B. Further, on the circumference of the rear end of the outer cylindrical ceramic member 21a, there is a 7-rank part n stretched outward, and on the circumference of the rear end of the inner cylindrical ceramic member 21b, there is a 7-rank part n stretched inward. n are formed respectively, and these 7 parts η
, 23 are in contact with the seven rungs 24 and 25 at the tip of the burner B, and the two are fixed with poles 26 and 27. The holding members 16 for holding the pulverized coal supply path 5 at a constant width are formed at three locations on the circumference of the inner wall of the outer cylindrical ceramic member 21, as in the previous embodiment.

In the burner B of this embodiment, since the ceramic members 21a and 21b inserted into the furnace are greatly affected by thermal shock, it is preferable to use silicon nitride ceramic, which has better thermal shock resistance than the above-mentioned alumina ceramic or silicon carbide ceramic. Desirably, this makes it less susceptible to thermal deformation in a high-temperature furnace and less susceptible to wear due to powder particles flying around in the furnace. For example, using the silicon nitride ceramic described above, the thick portion of the outer cylindrical ceramic member 21a is
Q m , when the thick part of the inner cylindrical ceramic member 21b is 150, the continuous use time of burner B is approximately 160
00 hours, which is a significant improvement in durability compared to the 4,000 hours of continuous use of conventional burners subjected to eight-dosing process.

- In the above embodiment, the mounting location of the mixing member was explained as being limited to the vicinity of the mixed fluid supply port and the vicinity of the spout of the burner, but the present invention is not limited to the above locations. Depending on the shape and structure of the burner, the tube support can be installed in a location where it is likely to be worn out by collisions with pulverized coal.

The above-mentioned ceramic is not limited to the type described in the above-mentioned embodiments, but any ceramic having good wear resistance and heat resistance can be used. - As explained above, according to the pulverized coal combustion burner of the present invention, a wear-resistant ceramic member is provided in the part of the pulverized coal supply path that is susceptible to abrasion due to collisions of pulverized coal, so that the burner can be easily heated by pulverized coal. Abrasion can be prevented and the durability of the burner can be improved.

In addition, the influence of heat can be reduced by using heat-resistant ceramic members in parts that are particularly susceptible to high temperatures.

Furthermore, since the ceramic member is removably attached, there are advantages such as ease of inspection or repair.

[Brief explanation of the drawing]

Fig. 1 is an explanatory cross-sectional view showing an example of a conventional pulverized coal combustion burner, Fig. 2 is a plan view near the transport pipe, Fig. 3 is an explanatory cross-sectional view taken along the line I in Fig. 1, and Fig. 4 is an explanatory view of the present invention. 5 is a cross-sectional explanatory diagram showing an embodiment of the pulverized coal combustion burner according to
6 is a sectional view taken along the line M-W in FIG. -■ line cross-sectional explanatory diagram. 1...Pulverized coal supply pipe 2...Air supply pipe 3...
Inner wall 4... Outer wall 5... Pulverized coal supply path
8... Spout port 10... Mixed fluid supply port 11,
12... Ceramic member 16... Holding member 211, 21b... Cylindrical ceramic member 24, b
...7 Lunge portion Patent applicant: Sumitomo Cement Co., Ltd. Figure 4 Figure 5 Figure 6

Claims (5)

[Claims] (1) An air supply pipe is provided inside the pulverized coal supply pipe (1) to create a multi-pipe structure, and between the inner wall G) of the pulverized coal supply pipe (1) and the outside W (4) of the air supply pipe ■. In the pulverized coal combustion burner configured as the pulverized coal supply path 6), a ceramic is installed in the pulverized coal supply path (5) which is likely to be abraded by the collision of the pulverized coal that is pumped in together with the pulverized coal supply air. A pulverized coal combustion burner characterized by being provided with a member. (2) In the vicinity of the mixed fluid supply port (10) of the pulverized coal supply path 6), a ceramic member (
The pulverized coal combustion burner according to claim 1, characterized in that lla) and (llb) are provided. (3) In the vicinity of the spout [F]) of the pulverized coal supply path 6), the inner wall G) of the pulverized coal supply pipe (1) and the air supply word (ZJ cD'/> M) $[128], (12b) [The pulverized coal combustion parcel according to claim 1, characterized in that it is provided with: (4) 7 rungs (24) at the tip of the 61 pulverized coal supply pipe (1) and the tip of the air supply pipe (2), C75”)
are formed respectively, and cylindrical ceramic members (21a) and (21b) are formed in the seven rungs (24) and (25), respectively.
A pulverized coal combustion burner according to claim 1, characterized in that a pulverized coal combustion burner is provided with a pulverized coal combustion burner. (5) Inner wall of pulverized coal supply pipe (1) (3 and air supply pipe (
2) and the outer wall <4>, and the pulverized coal supply channel 6)
The pulverized coal combustion bar according to claim 1, wherein the holding member (16) for holding the pulverized coal combustion bar at a constant width is made of ceramic. −