JPS58193006A - Burner for ground coke - Google Patents

Abstract

PURPOSE:To make the change of feeding ratio of ground coal and of burning condition easy, by providing classifying baffle plates to a passage to transfer ground coal by air flow, and also by dividing a burner tube itself into at least two branches. CONSTITUTION:Ground coal, passing through a passage 1 together with the air to transfer coal by air flow, is transferred to an elbow 2, where the direction of flow is changed about 90 degrees. Accordingly, the ground coal shows to tend to flow separating from the center line of a bent part of the elbow as a whole, that is, to flow inclined to the side of a change part 6. Especially, the larger the mass is and the larger the diameter is, a particle tends to go outside, so that the classification effect can be obtained. In order to make the rate of ground coal injected from each burner tube 3 and 4 approximately equal, the primary baffle plate 7 is to be turned to the direction X, while the secondary baffle plate 8 is turned to the direction X', so that the sectional area to let the coal into the burner tube 4 is increased and particles can be dispersed uniformly. On the contrary, the burner can be composed so as to reduce NOx into vapor phase by feeding more ground coal to the side of a burner 3, by utilizing the classification effect and also by controlling the above-mentioned baffle plates 7 and 8.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a burner for burning coal, such as pulverized coal, which has been pulverized into fine particles of a predetermined particle size.

With recent changes in the fuel situation, the value of coal as a fuel has been reconsidered, and a considerable number of large boilers for business use, including large boilers for thermal power plants, are now using co-fired fuel oil or coal-fired boilers. In this case, from the viewpoint of improving the efficiency and controllability of coal combustion, a method is adopted in which the coal is pulverized to a predetermined particle size and then air-flow conveyed to the burner section. There are various particle sizes of crushed coal, but
Usually, pulverized coal with a 200 mesh passing rate of about 70% to 80% is often used. The pulverized coal supplied into the furnace is rapidly heated by the heat inside the furnace and burns in a relatively short time.

The pulverized coal is usually blown out from the burner and combusted together with 20 to 50% of the theoretical amount of air, and is combusted by secondary air supplied from around the burner. In this case, the flow path is changed by approximately 90 degrees from the pneumatic transport pipe to the burner, but the pulverized coal transported by air flow is classified by inertia due to this change in flow path, and is sprayed unevenly from the burner. There is a risk that combustion may become unstable or difficult to control.

The object of the present invention is to uniformly inject pulverized coal by controlling this classification, or to form a main combustion zone and a reduction combustion zone with a -group nozzle to produce nitrogen oxides (hereinafter referred to as "NO").
The structure is such that the burner can be controlled in a wide range of ways, such as gas-phase reduction.

In short, this invention connects the burner section and the pipe line for pneumatically transporting the pulverized coal through an elbow bent at approximately 90 degrees, provides a classification adjustment body within or near the elbow, and further connects the burner tube itself with at least two This invention relates to a nozzle for burning pulverized coal that is divided into passages.

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

In Fig. 1, reference numeral 1 denotes a pipe for pneumatically transporting the pulverized coal in the pulverizer, and 2 indicates a flow path of the pulverized coal at an angle of about 90°.
It is an elbow that bends. The downstream side of the elbow 2 in which the pulverized coal flows is divided into two passages 2a and 2b, and the nozzle tubes 3 and 4 are connected to each passage 2a and 2b, respectively. The opening ends of three of these nookana tubes are directed upwards,
On the other hand, the cylinder 4 is opened slightly downward.

Reference numeral 5 denotes a lid body provided on the outer circumference side of the bent part of the elbow 2 that is most likely to wear out, and on the inside, a replacement member 6 forming a part of the inner circumferential surface of the elbow is attached to and detached from the lid body 5 with bolts or the like. Furthermore, the lid body 5 itself is detachably attached to the seven rungs 2C of the elbow 2 with bolts or the like.

Reference numeral 7 denotes a primary adjustment plate that rotates around a rotation shaft 7a, and is arranged near the entrance of the elbow 2.

Reference numeral 8 denotes a secondary adjustment plate, which is disposed at the branching part of the passages 2a and 2b, and swings about the rotating shaft 9 as shown by the arrow to adjust the amount of pulverized coal flowing into each burner cylinder 3 and 4. Adjust.

Next, numeral 10 is a secondary air passage formed around the burner cylinders 3 and 4, 11 is a tertiary air passage formed on the outer periphery of the secondary air passage 10, and 12 is an air passage formed in the secondary air passage. The travel vane 13 is a travel vane for the tertiary air passage. Further, reference numeral 14 is an ignition torch.

In the above-described apparatus, the pulverized coal passes through the pipe 1 together with the pneumatic transport air to reach the elbow 2, where its flow direction is changed by about 90 degrees. For this reason, the pulverized coal as a whole tends to flow away from the bending center of the elbow, that is, toward the exchange member 6 side, and the large-diameter particles, which have a particularly large mass, flow outward, producing a classification effect. If you want to make the pulverized coal injected from each burner cylinder 3 and 2 almost uniform, by rotating the - secondary adjustment plate 7 in the X direction and rotating the secondary adjustment plate 8 in the X' force direction) The cross-sectional area flowing into the gunner cylinder 4 is increased, and the particles are uniformly dispersed.

Conversely, it is also possible to make use of this classification effect and adjust the adjustment plates 7 and 8 to supply more pulverized coal from the nozzle tube 3 side G to reduce NOx in the gas phase. good.

In other words, the air (-air) that has carried the pulverized coal by pneumatic flow flows into each burner cylinder in almost the same amount, regardless of the classification effect of the pulverized coal, so the amount of pulverized coal that flows in If this increases, the air-fuel ratio of this inner tube will inevitably decrease.

In other words, by adjusting the adjusting plates 7 and 8, the knob cylinder 3 can be adjusted.
to lower the air-fuel ratio (for example, 1 or less, preferably 0.5 or less, including secondary and tertiary air) to perform low 02 combustion,
On the other hand, in the burner cylinder 4, the air-fuel ratio is set to approximately 1 to achieve complete combustion. A reducing intermediate product is generated by the low 02 combustion in the burner cylinder 3, and the NOx generated by the combustion in the burner cylinder 4 is reduced to N2 in the gas phase. By distributing the pulverized coal in this manner, one burner can both bear the heat load of the combustion device and remove NOx.

A replacement member 6 is disposed on the outer side of the pulverized coal flow, which is the most abrasive surface of the inner surface of the elbow 2. If this member becomes worn, it can be removed from the elbow 2 along with the lid 5 and replaced with a new member. Exchange.

2 and 3 show another embodiment.

In the case of this embodiment, whereas in the previous embodiment the burner cylinder is completely separated into two, a partition plate is arranged within one burner cylinder to form a plurality of passages. Reference numeral 20 denotes a burner cylinder connected to the outlet side of the elbow 2. Inside the burner cylinder, passages 22 and 23 are defined vertically by a partition plate 21, and the lower passage 23 is separated by another partition plate 24.
It is divided into passages 23a and 23b. A secondary adjustment plate 25 is attached to the elbow side end of the partition plate 21, and is configured to swing in the direction of the arrow x#yJF. Together with the primary adjustment plate 7 formed near the elbow inlet, this G adjusts the amount of pulverized coal flowing into each passage. In the case of this embodiment, since only one cylinder is required, manufacturing costs can be kept low.

FIG. 4 shows a third embodiment of the invention, in which the lower passage 23
An impeller rod 30 is disposed inside, and an impeller 31 is disposed at the opening of the lower passage 23 by means of the rod 30. The flame formed by the fuel injected from the passages 22 and 23 is divided by the impeller 31, thereby forming a reducing flame more completely and performing effective gas phase reduction.

By implementing this invention, it is possible to freely change the supply ratio of pulverized coal to at least two burner passages, so that gas phase reduction and complete combustion can be performed in one burner,
Various controls such as uniformity of the supply ratio of pulverized coal are possible.

[Brief explanation of the drawing]

1 is a sectional view of a burner for burning pulverized coal showing a first embodiment of the present invention, FIG. 2 is a sectional view of a burner for burning pulverized coal showing a second embodiment, and FIG. FIG. 2 is a sectional view taken along line A--A in FIG. 2, and FIG. 4 is a sectional view of a burner showing a third embodiment. 1... Airflow transport pipe 2... Elbow 3, -'
4.20... Burner 6... Replacement member 7...
- Soft adjustment plate 8...Secondary adjustment plate 21...Partition plate 22...Upper passage 23...Lower passage
25...Secondary control plate 31...Impeller Continued from page 1 0 Author Toshiaki Nakahara 6-9 Takaracho, Kure City Babcock Hitachi Co., Ltd. Kure Factory

Claims (1)

[Claims] 1. In a device that injects and burns pulverized coal together with combustion air, a pulverized coal airflow conveying pipe and a plurality of pulverized coal passages constituting a burner cylinder are connected via an elbow. A burner device for burning pulverized coal, characterized in that the amount of pulverized coal flowing into each of these pulverized coal passages can be adjusted by connecting the two pulverized coals and arranging at least one adjustment plate in or near the elbow. 2. The burner device for burning pulverized coal as set forth in claim 1, wherein the downstream side of the elbow is branched into two passages, and a burner cylinder is connected to each of these passages. 3. The burner device for combusting pulverized coal as set forth in claim 2, characterized in that an adjustment plate is provided at a passage branching portion within the elbow. 4. The pulverized coal according to claim 1, wherein a burner cylinder is connected to the downstream side of the elbow, and a partition plate is provided inside the burner cylinder to define an upper passage and a lower passage. Combustion bar device. 5. The burner device for burning pulverized coal according to claim 5, characterized in that an impeller is disposed in the opening of the lower passage. 6. The burner device for burning pulverized coal as set forth in claim 5 or 6, characterized in that an adjustment plate is provided at the elbow side end of the partition plate. 7. The burner device for burning pulverized coal according to any one of claims 1 to 6, characterized in that an adjustment plate is provided near the elbow inlet. 8. Pulverized coal combustion according to any one of claims 1 to 7, characterized in that a replacement member in case of wear is arranged on the inner surface of the elbow, which is the outer side of the flow of the pulverized coal. burner equipment.