JPS6287709A - Pulverized coal burner using low calorie gas as assist fuel - Google Patents

Abstract

PURPOSE:To enable holding of a stable flame even when solid fuel having fire retardancy is assist-burnt and to improve a combustion rate, by a method wherein low calorie gas is divided into plural parts to feed it in the vicinity of a burner throat wall, the gas is stably burnt by a potential heat from a throat part, simultaneously, the refractory of the throat part is heated to a high temperature to use it as an ignition source. CONSTITUTION:A burner is so constituted that low calorie gas flows through a passage away from a pulverized coal 2, flame is collided with bricks 8 of a profile burner throat part, and a potential heat, which the burner throat bricks 8 have, can be effectively utilized. A passage, through which the air for combustion flows, is formed between a passage, through which pulverized coal 16 flows, and a passage, through which low calorie gas flows. Low calorie gas 17 is divided into at least 2 or more parts, an seen from the front, and a gas passage is formed in a shape which prevents the air for combustion from impeding an air flow through an inlet passage and is formed in comformity with the flow of gas flowing through an air resistor 6. This increases the area of a contact surface between fuel gas and the air for combustion, enables the temperature of a gas flame to be maintained at a high value, and permits ensurance of the burning rate of pulverized coal.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Field of Application> The present invention relates to a combustion equipment capable of burning a combination of flame-retardant high fuel ratio coal and low-calorie gas that is difficult to self-combust.

<Conventional technology and its problems> With recent changes in the fuel situation, it has become possible to reduce operating costs by burning flame-retardant solid fuels such as coal with a high fuel ratio (poor coal) and petroleum coke in combustion furnaces such as boilers. There are a number of consultations and ideas for lowering the price.

On the other hand, in steel mills and oil refinery plants, these? ! 1
There are hopes to use the low-calorie gas produced as a by-product during the production process as an auxiliary fuel for extremely bad coal, petroleum coke, etc. to achieve an oil-free process.

The reason for this is that poor quality coal with a fuel ratio of 4.0 or higher and petroleum coke cannot maintain flame stability due to the high fuel ratio (fixed carbon/volatile content) and low volatile content. In the conventional technology, a method was adopted in which heavy oil or high-calorie gas consisting of 5 to 20% human heat 11 was put into the same burner to form a high-calorie gas flame, and the energy of the oil gas flame was used to burn powdered coal in a flame-holding manner. Figure 4 shows the charcoal bar proposed by the applicant.
Suno1lII, I/construction not shown. The burner 1 shown in the figure is a high-power pulverized coal burner with gas auxiliary combustion.The pulverized coal 16, such as coarse coal, petroleum, and cous, is pulverized by a crusher on the upstream side and transported by air flow. The pulverized powder is radiated into the furnace through the pulverized coal L and g9 by the impeller attached to the tip of the pulverized coal burner a. At the tip, an auxiliary combustion gas flame 1.1 made of high-calorie gas is formed in advance, and the pulverized coal is supplied to the inside of the gas flame. As a result, the radiant heat of the high-temperature gas flame and the swirling force of the combustion air from
The pulverized coal is mixed with air and combusted in a furnace. According to the above-mentioned bath G, high-calorie oil or gas is used as auxiliary fuel 7, so when this is replaced with low-calorie gas 1, the low-calorie gas itself becomes N22
Since it contains a large amount of inert gas such as CO2HN20, it is difficult to hold the flame with the auxiliary combustion gas itself, and even if the auxiliary combustion rate is increased because it contains a large amount of inert gas, the atmosphere around the pulverized coal is an inert gas with little oxygen. (assuming that the coefficient of 1chi becomes lower) is that of O with an open chain.

In addition, the above-mentioned Vanilla C1-1 low calorie burner ((itself is also 1〒1) is difficult and young, and the misfire type 1 is likely to blow over and burn (12), so the combustion is unstable. Therefore, it was considered that conventional burner devices could not perform auxiliary combustion of pulverized coal at a high fuel ratio using low-calorie gas.

Object of the invention> Object of the invention (4) Low calorie gas (e.g. stone;
To provide a burner device 1t capable of maintaining a stable flame even when auxiliary combustion of carbonaceous coal is performed, and capable of increasing twisting and skewering.

Overview of the means for achieving this> υIn other words, this invention supplies low-calorie gas in multiple parts near the burner throat wall, stably burns it using the heat retained in the throat, and at the same time heats the refractory material in the throat to a high temperature to ignite it. By using the low calorie gas flame as a source, the pulverized coal flow is passed through the sand winch G to produce stable and highly efficient natural gas L+'l.

<Example> An example of the present invention will be described with reference to FIGS. 1 to 3. The symbols used in these drawings are the same as those in FIG. 2 Constructed so that the flame hits the irregularly shaped burner throw 1/part Aji tile 8G via a passage away from the pulverized coal 1
,, B is that the burner throat brick 8 is a purchased product that can utilize the retained heat. For this reason, the shape of the burner throat brick 8 is such that the flame collides with the low-calorie fuel gas flow, causing the colliding portion to become incandescent and to be used as an ignition source. The second point is that compared to high-calorie gas Q, low-calorie gas requires 10-20 times the gas volume to supply the same heat input II1, and the gas jetting speed is also low and blows away. It was designed to prevent C and N2 contained in the fuel. Co2. Add a lot of inert gas such as N20.
Since the pulverized coal contains 18 carbon atoms, these inert gases may prevent mixing and contact with air, thereby inhibiting the combustibility of the pulverized coal burner.

Between the passage through which the pulverized coal 16 flows and the passage through which the low-force gas flows - The gas passage shape of the division 17 is such that it follows the gas flow C1 passing through the air register 6 without obstructing the air flow in the combustion air entry passage.

The third point is to use low-calorie gas with low power.
1) Iiii
The flame that has been extinguished by blowing the flame into the brick 8 at the throat part (8a') is blown onto the pulverized coal 16, and the heat F (temperature) G of the low calorie gas flame is Therefore, the points I and X are arranged so that the pulverized coal flame 15 forms a circumferential ball with one extraction center around the burner axis.

Furthermore, to devise a structure of a low-calorie gas burner for auxiliary combustion when promoting the combustion of pulverized coal with a high fuel-to-fuel ratio, pulverized coal itself, and poor flame stability. This will function as follows.

First of all, the low calorie gas itself does not have good flame-holding ignition properties, because it collides with the refractory in the throat and becomes self-combustible as an ignition source, and the fuel is divided into two parts. , the contact surface between the fuel gas and combustion air is wide, and the gas flame temperature can be maintained high.

Furthermore, by blowing a low-calorie gas flame onto the outer periphery of the pulverized coal, it serves as energy for igniting the pulverized coal.

Roughly speaking, fresh combustion air is supplied to the outer periphery of the pulverized coal in a sandwich-like manner, which not only ensures the combustion rate of the pulverized coal, but also forms a streamlined fuel gas flow path that is integrated with the air flow path. This new low-calorie gas solves all the problems that can be expected to occur due to the auxiliary combustion of a series of low-calorie gases, such as maintaining the turning force and minimizing wind pressure loss. This is a burner groove layer that burns high fuel ratio coal.

Regarding the burner groove layer mentioned above, (1) In the past, when burning flame-retardant powdered coal (heavy oil or high-calorie gas was used as an auxiliary fuel, I can't find any plans or examples regarding this.I think this invention is the first one.

(2) Off gas (400-600KCal/m'N)
During combustion, a low-calorie gas flame is blown onto the furnace material to ensure flame stability, and the flame is maintained by the heat retained in the furnace material. I'm not talented.

In addition, for G17:f products that have extremely low self-combustion due to the calories of the combustible components contained in low-calorie gases, a device can be installed that heats the bricks in the burner throat area with high-calorie gas to make them incandescent when starting up from a cold can. .

<Effect of the invention> By implementing the present invention, the following effects can be obtained.

(1) Low calorie gas can be ignited by the heat possessed by the bricks in the throat section, allowing the low calorie gas to self-heat, and depending on the calorie level of the low calorie gas, this low calorie gas can be used as starting fuel.

(2) Since flame-retardant pulverized coal can be burned with low-calorie gas, fuel costs can be reduced.

(3) Fresh air can be supplied around the flow of combustible pulverized coal and the combustion rate will not deteriorate.

(4) Since it has a low calorie gas flow path along the combustion air flow path, the pressure loss of the air flow is small and the combustion rate can be improved without hindering the air swirl required for combustion of powdered coal.

These have made it possible to burn poor quality coal by auxiliary combustion with coal gasification gas and process by-product gas, making it possible to use energy effectively.

[Brief explanation of drawings]

Fig. 1 is a vertical sectional view of a burner showing an embodiment of the present invention, Fig. 2 is a sectional view taken along line A-A in Fig. 1, and Fig. 3 is a sectional view taken along line B-B in Fig. 1.
4 is a vertical cross-sectional view of a pulverized coal combustion equipment using high-calorie gas. 1... Wind box 2... Pulverized coal burner 8... Irregularly shaped burner throat brick 8a...
...Etsuji

Claims (1)

[Claims] 1. A passage for pulverized coal with a high carbon ratio, a secondary air passage for combustion, a tertiary air passage for combustion, and a low-calorie gas passage are provided in parallel from the axial center side, and the passage for the pulverized coal is separated from the secondary air passage for combustion. A flame holding ring is provided at the end of the partition wall and at the furnace side end of the partition wall that separates the combustion tertiary air passage and the low-calorie gas passage, and the low-calorie gas passage is located at its end in the circumferential direction when viewed from inside the furnace. The refractory member of the burner throat portion that corresponds to the calorie gas passage has an edge portion, and the low calorie gas flame is directed to the ejected powder coal flow at the edge portion. A pulverized coal burner using low-calorie gas as an auxiliary fuel, characterized in that the burner is configured to be deflected by a pulverized coal burner.