JPS5927107A - Divided flame type pulverized coal burning equipment - Google Patents

Abstract

PURPOSE:To divide the flame and consequently reduce the rate of formation of nitrogen oxides by a method wherein more than one thread of spiral grooves are formed on the lining layer forming the inner wall surface of a pulverized coal injection tube in order to cause the local change of the concentration of injected pulverized coal. CONSTITUTION:The air stream to carry the pulverized coal is given swirling force by means of a swirl vane 13 in order to scatter uniformly therein the pulverized coal, which is further uniformized by passing through a venturi 2 and again given swirling force by means of the grooves 33 and at the same time the pulverized coal itself is advanced in such a manner as to scour each groove 33 and jetted from the injection tube 1. In other words, high concentration areas of the pulverized coal jetted along the grooves 33 and its remaining comparatively low concentration areas are developed alternately in space. A burner arranged within a furnace 31 is divided its flame in correspondence to the local change of the concentration of the pulverized coal. The division of the flame into a plurality of small independent flames results the lowering of flame temperature and consequently the suppression of the formation of NOX.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pulverized coal combustion device, and more particularly to a pulverized coal combustion device that can reduce the generation of room floor oxides by splitting the flame.

The value of coal as a fuel has recently been reconsidered due to soaring oil prices. This situation is the same in power plant workers 1 (1). In this case, in order to improve the efficiency and controllability of coal combustion, the coal is finely pulverized to a 200 mesh passage rate of about 70% ( (hereinafter referred to as pulverized coal) is often used.

Common to all combustion devices, it is desired to reduce the amount of nitrogen oxides (hereinafter abbreviated as NOx) U1 produced by combustion as much as possible. This also applies to equipment that burns pulverized coal, and NOx generation 1
It is desired to develop a device with less i.

This invention has the above-mentioned key points! The purpose of this invention is to provide a combustion device that generates less NOx (1+t).

In short, this invention forms one or more spiral-shaped rllll- on the wall surface of the injection chamber where pulverized coal is injected, and divides the flame of pulverized coal injected from the injection cylinder to reduce NOx, and also This Dlj; is constructed so that the inner lining forming the 4-shaped groove is made of ceramic to improve wear resistance.

Examples of the present invention will now be described.

In FIG. 1, reference numeral 1 indicates a pulverized coal injection pipe, the tip of which opens through a throat 30 to the furnace 31 side, and the base of which is connected to an elbow 8. Reference numeral 9 designates an inner cylinder support part provided on the elbow 8, and 10 represents an inner cylinder supported by the support part, which is arranged so as to be located approximately on the same axis as the intermediate pipe within the pulverized coal supply pipe. be. Reference numeral 11 denotes a burner for auxiliary combustion or ignition disposed within the inner cylinder. 14 is a pulverized coal supply pipe connected to the elbow 8; and 13 is a rotating vane installed in the elbow near the connection part of this pulverized coal supply pipe.

Next, reference numeral 2 is a venturi provided at the artificial part of the pulverized coal injection pipe 1, and a plurality of grooves 33 are formed on the inner wall surface of the injection pipe on the downstream side of the venturi installation part. The grooves are formed by forming a wear-resistant lining layer 34 on the inner surface of the injection pipe 1, and forming, for example, two or three spiral grooves 33 on this lining layer. Note that ceramics with high wear resistance is effective as the lining layer 34.

15 is an inert gas passage formed on the outer periphery of the pulverized coal injection pipe 1, 17 is a secondary air passage formed on the outer periphery of the inert gas passage 15, and 25 is a secondary air passage formed further on the outer periphery of the secondary air passage. It is a tertiary air passage.

18 is a flow rate regulating vane provided at the entrance of the secondary air passage;
9 is a lever for operating the same vane, 26 is a flow rate adjusting vane provided in the tertiary air passage, and 27 is a lever for operating the same vane. 21 is a secondary air swirling vane, 22 is a link for operating the vane, and 28 is a tertiary air swirling vane.

In the above-mentioned apparatus, the pulverized coal C airflow-transported by the air to be used as the next air for combustion flows from the pulverized coal supply pipe 14 into the elbow 8, where the flow path is changed approximately 90 times to form the pulverized coal injection pipe 1. flows into. In this case, the swirling vanes 13 impart a swirling force to the pulverized coal transporting airflow - provided that the pulverized coal is uniformly dispersed in the airflow. Next, it passes through a venturi 2 and is further homogenized. In this venturi 2 portion, the pulverized coal is uniformly diffused in the circumferential direction Gpz of the injection pipe 1. The pulverized coal-containing airflow is given a swirling force by the groove 33, and the pulverized coal white is injected from the advancing injection pipe 1 so as to scrape each surface 33 by centrifugal force. In other words, at the injection pipe opening, the groove 33G
Along this line, areas with a high concentration of pulverized coal and other areas with a relatively low concentration of pulverized coal are generated alternately, and the burner flame in the furnace 31 is divided according to the density.

By dividing the flame into a plurality of independent small flames in this manner, the flame temperature is lowered and the generation of NOx is suppressed. In addition, before adding density to the flow of pulverized coal from the groove 334,
Once the injection pipe σ] is uniformly distributed in the circumferential direction, approximately the same amount of pulverized coal rubs against each surface.
Stable combustion can be achieved without any difference in density in each high concentration region or in each low concentration region. Secondary air in the above combustion process.

The amount of tertiary air supplied and the swirling force are controlled, and combustion exhaust gas G, for example, is supplied as an inert gas from the inert gas passage 15 to further reduce NOXt.

By carrying out this invention, pulverized coal σ)'h'4;
1. In the I'e process, nitrogen oxides σ] can be generated (11).

[Brief explanation of drawings]

FIG. 1 shows a pulverized coal combustion apparatus aJ Ill according to the present invention, and FIG. 2 shows 1 of FIG. +7 I line G break +f
ii DA. 1... Pulverized coal injection pipe 33... Groove 34... Lining layer

Claims (1)

[Scope of Claims] 1. In a device in which pulverized coal is air-transported to a pulverized coal injection pipe and injected from the pulverized coal injection pipe for combustion, a lining layer is formed on the inner wall surface of the pulverized coal injection pipe. A flame splitting type pulverized coal combustion device characterized by forming one to two spiral grooves on the pulverized coal to give the injected pulverized coal a rich and light density. 2. The flame splitting type pulverized coal combustion device according to claim 1, wherein the lining layer is made of ceramic.