JPS58224207A - Pulverized coal firing equipment - Google Patents

Abstract

PURPOSE:To normally perform an appropriate combustion and besides to reduce a quantity of a nitrogen oxide produced, by enabling the uniform jetting of a pulverized coal and also by controlling a quantity of the air supplied. CONSTITUTION:The installation of a passage 15 for feeding an inactive gas formed around a tubular body 1 causes sealing of the flame of a burner against entrance of a secondary air through jetting of an inactive gas from a jet nozzle 15a, and enables the remaining inactive gas to flow in the tubular body through an opening 6. A secondary air passage 17 is formed around an inactive gas passage 15. The degree of opening of a flow rate regulating plate 18, located in the inlet of the secondary air passage, is adjusted by a lever 19 and a link 20 connected thereto to regulate the flow rate of the secondary air. A vane 21 for swirling the air turns a shaft 22 for rotating the vane through a lever 23 and a bevel gear 24, and regulates a swirling force of the air through control of the angle of the vane 21 for swirling the air.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a combustion device for burning coal that has been crushed into fine particles, such as pulverized coal.

Due to recent changes in the fuel situation, the fuel Mlli value of coal has been reviewed, 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 pulverized coal, but pulverized coal with a 200 mesh passing rate of about 70 to 80% is usually used. (Pulverized coal will be explained below.) Since the pulverized coal supplied into the furnace is rapidly heated by the heat inside the furnace and burns in a short time, controllability is improved compared to stoker firing or the like.

Pulverized coal is normally blown out of the burner 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 purpose of this invention was to solve the above-mentioned problems, and it is possible to uniformly inject pulverized coal, control the amount of air supplied to ensure proper combustion at all times, and reduce the amount of nitrogen oxides (NOx). It is an object of the present invention to provide a burner device which can also reduce the amount of oxidation produced.

In short, this invention arranges a secondary air passage and a tertiary air passage whose flow rate can be controlled around a cylindrical body serving as a pulverized coal passage, and connects a passage supplying an inert gas to the cylindrical body.
Further, each air passage is a pulverized coal combustion device in which the air flow rate, air swirling force, etc. can be adjusted.

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

In FIG. 1, 1 is a cylindrical body, and venturis 2 and 3 are formed within the cylindrical body 1. Among these, the venturi 2 is configured to be able to slide inside the base [a] of the cylindrical body 1. 31 is a lever for sliding this venturi 2.

This cylindrical body 1 is divided into two parts, a base part 1a and a tip part 1b, and by operating a 14-digit lever 5 attached to a sliding ring 4, the ring 4 is slid, and an opening for introducing inert gas is opened. The structure is such that the area of 6 can be made variable.

8 is an elbow connected to the base 1a of the cylindrical body 1, and the details of its structure are shown in FIGS. 2 and 3. 9 is elbow 8
This is a support cylinder disposed inside the cylindrical body 1, and supports a guide cylinder O disposed within the cylindrical body 1 so that one central axis is substantially the same.

Reference numeral 11 denotes a heavy oil burner disposed within the guide tube 10, which is used, for example, for igniting pulverized coal. Reference numeral 12 denotes a pulverized coal particle mixing vane that also functions as a support plate for supporting the support cylinder 9, and provides a swirling force to the pulverized coal-containing gas flowing from the lower part of the elbow. Reference numeral 13 is another pulverized coal mixing vane provided at the elbow portion, and 14 is a pulverized coal supply pipe connected to this elbow 8.

Next, 15 is an inert gas supply passage formed around the cylindrical body 1, in which inert gas is injected from the injection 1'' 15a to seal the burner flame from secondary air, and the remaining inert gas is Gas is allowed to flow into the cylindrical body through the opening 6. Reference numeral 16 denotes a pipe J for supplying inert gas to this inert gas passage.

Next, 17 is a secondary air passage, which is formed around the inert gas passage 15. Reference numeral 18 denotes a flow rate adjustment plate formed in the same secondary air passageway, and its opening degree is adjusted by a lever 19 and a link 2o connected thereto to adjust the secondary air flow rate. 21 is an air swirling vane arranged at the outlet of the secondary air passage, and lever 23. The vane rotation shaft 22 is rotated via the bevel gear 24, and the angle of the rotation vane 21 is adjusted to adjust the rotation force of the air. In this case, each rotating vane is connected to the lever 23 by a link mechanism (not shown).
The angle is changed at the same time by the operation of .

25 is a tertiary air passage formed on the outer periphery of the upper secondary air passage 7; 26 is a flow rate adjustment plate provided on the tertiary air passage 1; 27 is a lever for rotating the adjustment plate; 28 is a 3 This is a vane for swirling the tertiary air placed at the outlet of the secondary air passage, and has the same configuration as the vane 21 described above.
9. The angle is adjusted by the bevel gear 30° vane rotation shaft to adjust the turning force of the tertiary air.

In the above device, the pulverized coal-containing gas that has ascended through the pulverized coal supply pipe 14 is given a swirling force by the pulverized coal mixing vane 13 at the entrance of the elbow 8, flows into the elbow, and changes this flow path by about 900 degrees. . In the case of this flow path change, the pulverized coal tends to be classified to the outside of the flow due to inertia, but since a swirling flow is formed by the vanes 13, the classification tends to be suppressed. Another vane 12 applies a swirling force to the airflow after the flow path has been changed, so that the pulverized coal in the airflow is uniformly dispersed. The flow of pulverized coal exiting the elbow 8 is on the right side of the venturi 2, and the cross-sectional area of the flow path is reduced, so that the distribution of pulverized coal is further made uniform, and the inert gas G (e.g. combustion exhaust gas) flowing in from the opening 6 is mixed in.

Furthermore, it passes through the venturi 3 and is injected into the furnace where it is combusted. On the other hand, from the secondary air passage 17 and the tertiary air passage 25, two
Secondary air and tertiary air are injected to surround the burner flame to prevent an increase in NOx production due to rapid mixing of the flame and air. In this case, inert gas passage 1
If the inert gas G is injected into the furnace through step 5, the secondary and tertiary combustion air and the burner flame can be temporarily separated, so NOx can be reduced more effectively. I can do it. During this time, the opening 6 is adjusted by the lever 5 to adjust the amount of inert gas G flowing into the inner cylinder. Also,
The lever 19 and the flow rate adjustment plate 18 adjust the secondary air flow, and the lever 27 and the flow rate adjustment plate 26 adjust the tertiary air flow rate. Further, by adjusting the angle of the swirling vanes 21 and 28, a predetermined swirling force is applied to each air to maintain proper pulverized coal combustion at all times.

Further, if a heavy oil burner 11 is provided in the guide tube 10 as shown in the figure, the pulverized coal can be ignited by this burner, and there is no need to provide an ignition burner.

By implementing this invention, pulverized coal can be uniformly dispersed and injected into the furnace, so combustion is stable and proper combustion can be performed at all times.

Also, the supply amount of secondary air and tertiary air, and the turning force.

and the amount of inert gas supplied can be freely adjusted, reducing NOx
The amount of produced can be reduced.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of a pulverized coal combustion device showing an embodiment of the present invention, Fig. 2 is a perspective view of an elbow, and Fig. 31... Cylindrical body 23... Venturi 6...・Inert gas inflow opening 8...Venturi] 0...Guide cylinder 11...Heavy oil burner 12.13...Vane for pulverized coal mixing]-5...
...Inert gas passage 17...Secondary air passage 18.26...Flow rate adjustment plates 21, 28...Swivel vane 25...Third air passage

Claims (1)

[Claims] 1. In a burner device in which a cylindrical body is used as a pulverized coal passage, a secondary air passage is provided surrounding the cylindrical body, and a tertiary air passage is provided surrounding the secondary air passage, the cylindrical body is provided with a pulverized coal passage. A gas passage surrounding the body and supplying an inert gas is provided, a secondary air passage and a tertiary air passage are provided surrounding this, a flow rate control plate is provided in the passage, and a flow rate control plate is provided in the secondary air passage and/or the tertiary air passage. is a pulverized coal combustion device characterized by having controllable rotating vanes. 2. The pulverized coal according to claim 1, characterized in that one or more venturi parts are provided in the cylindrical body, and a pulverized coal particle mixing vane is provided in the elbow connected to the cylindrical body. Combustion device. 3. The pulverized coal combustion device according to claim 2, wherein the cylindrical body is provided with an inert gas introduction opening, and the opening of the bracket is provided with an opening adjustment device. 4. Claims 2 or 3, characterized in that a guide cylinder is provided at the axis of the cylindrical body in order to equalize the concentration of pulverized coal, and a heavy oil burner is located within this guide cylinder. Pulverized coal combustion equipment as described in Section 1. 5. The pulverized coal combustion device according to claim 3, characterized in that a portion of the venturi is freely adjustable in displacement in the axial direction of the cylindrical body.