JPS62258924A - Combustion furnace nozzle device - Google Patents

Abstract

PURPOSE:To reduce a pressure loss in supplying fuel and improve an efficiency of a combustion furnace by a method wherein a Coanda spiral flow generating part including means for supplying pressurized fluid to a fine clearance arraged at a cylindrical pipe and means for supplying fuel fluid to an inlet port for fuel fluid is arranged. CONSTITUTION:Air and water acting as pressurizing fluid are fed at high speed from a fine clearance 3 into a cylindrical pipe 2. Fluid at an outlet of the fine clearance 3 may form a flow line alpha from the cylindrical pipe to a line passage 1 under a Coanda effect, resulting in that a negative pressure area is generated at an opposite side. Fuel fluid flows from an external part to the negative pressure area (arrow beta). A motion vector of the fluid from the fine clearance 3 and another motion vector of fuel fluid from external side are combined to each other to form fluid flow advancing in the cylindrical pipe toward the line passage 1. The fluid flow is gradually reduced in its diameter and during this process its radial vector is applied. This vector is converted into a circulating vector to generate a spiral motion together with a straight forwarding vector. In this way, as the fuel fluid is transferred to an outlet of nozzle through the Coanda spiral flow, a nozzle part 10 may discharge the fuel fluid into a combustion furnace.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a nozzle device for a combustion furnace and a combustion furnace. More specifically, the present invention relates to a high-efficiency combustion furnace nozzle based on one type of Coandas Bacalar flow and a combustion furnace using the nozzle.

(Conventional technology and its challenges) Since the oil crisis, interest in energy conservation and alternative energy has increased, and studies on efficient and low-cost energy use are underway in a wide range of industrial fields.

Various energy saving and energy saving methods have already been adopted in many fields, and improvements are being made in devices and equipment that utilize thermal energy, including heating furnaces and combustion furnaces.
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In addition, in recent years, interest in the use of coal has increased, and CO
The use of M (coal/oil mixed fuel), CWM (coal/water mixed fuel), or granular coal has begun.

As the development and use of such energy saving and alternative energy advances, various improvements have been made to the structure of combustion furnaces for converting fuel into thermal energy and effectively utilizing that thermal energy.

Examples include improving the furnace wall structure of a combustion furnace to prevent loss of thermal energy, and improving the nozzle tip to improve the contact efficiency between the fuel and burner flame.

However, in these conventional techniques, there has not been much improvement in the nozzle device for feeding fuel into the combustion furnace. In particular, coal utilization, COM, C
Conventional technology has had major problems with nozzle devices that can accommodate the new situation of using new fuels such as WM.

That is, when solid fuel particles such as coal and coke, or fluids containing solid particles such as COM and CWM, are used as fuel, conventionally, a turbulent mixed transport method such as a so-called ejector one-type method has been employed. In this method, high-speed air or liquid fluid is in a state of turbulent mixing with solid particles, so the particles violently collide with the inner wall of the pipe before being ejected from the outlet at the tip of the nozzle.
This wear of the inner wall was unavoidable. Moreover, this wear rapidly progresses to the point of destruction of the pipe line.

Therefore, in order to suppress this wear and to properly control the supply of fuel into the combustion furnace, the pipe material must be made of a special material with high impact resistance and durability, or ceramic It was necessary to strengthen the inner wall of the tube by means such as internal coating. Moreover, the same thing was required not only for pipes but also for valves, pipe fittings, and measuring instruments such as flowmeters and pressure gauges.

Furthermore, pressure saw loss is large when turbulent mixing is used, and in order to increase the efficiency of fuel supply and combustion furnace, it is necessary to increase the size of the pressure equipment for fuel supply.

Therefore, it has been strongly desired to realize a nozzle device for a combustion furnace that is free from such problems and has excellent efficiency and economical efficiency, and a combustion furnace using the nozzle device.

(Object of the Invention) This invention was made in view of the above circumstances, and aims to provide a nozzle device for a combustion furnace that solves the problems in the conventional method, and a combustion furnace using this nozzle. The purpose is

(Structure and Effects of the Invention) The nozzle device for a combustion furnace of the present invention is for efficiently supplying fuel, particularly a fuel fluid containing solid particles, into a combustion furnace while suppressing wear on the inner walls of pipes, etc. It is characterized by the adoption of a Coanda spiral flow system instead of the conventional fuel supply method using turbulent flow mixing.

This Coanda spiral flow and its industrial use were first discovered by the inventor of this invention.When a vector in the radial direction of the pipe is added to the vector of the fluid in the direction of the pipe, the fluid swirls, and this swirling flow This is based on the fact that a dynamic boundary layer is formed near the inner wall of the base pipe, and the fluid moves at high speed in the direction of the pipe while drawing a spiral.

When solid particles are mixed into this spiral flow, the particles proceed in the direction of the pipe while causing a spiral, and contact between the particles and the inner wall of the pipe is significantly suppressed.

This invention utilizes such a Coanda effect.

A nozzle device of the present invention and a combustion furnace using the same will be explained in accordance with the drawings.

FIG. 1 shows a cross-sectional view of an example of a nozzle device of the present invention. The nozzle device of the present invention illustrated in FIG. ) is formed with an annular slit (3) for feeding pressurized fluid into the cylindrical pipe, and the slit (3)
A smoothly curved wall (4) is provided from the cylindrical pipe toward the pipe (1), a fuel fluid inlet (5) is provided at the opposite end of the cylindrical pipe, and a slit is provided. (3) a Coanda spiral flow generation unit provided with a means for supplying pressurized fluid to the fuel fluid inlet (5) and a means for supplying fuel fluid to the fuel fluid inlet (5); It consists of a pipe section for transferring and a nozzle section for discharging the fuel fluid into the combustion furnace.

On the side opposite to the wall surface (4) of the slit (3), there is an auxiliary cylinder (8).
Alternatively, the portion corresponding to this auxiliary tube may be integrated with the cylindrical tube (2). However, the slit (
Regarding the gap 3), it is preferable to make it freely adjustable in order to control the fuel supply while monitoring the condition of the combustion furnace. Moreover, the wall surface (9) facing the curved surface (4) in the gap (3) is bent into a substantially right-angled or acute-angled shape.

Any suitable means (7) for supplying pressurized fluid to the annular slit (3) can be adopted, but a distribution chamber (6) is provided to surround the cylindrical pipe (2), and this distribution chamber and The slit (3) can be communicated with the slit (3).

In this construction, a pressurized fluid, such as air, water, etc., is pumped at high speed through the slot (3) into the cylindrical tube (2).

At the exit of the slit (3), the fluid draws a streamline (α) tilted from the cylindrical pipe toward the pipe (1) due to the Coanda effect, and as a result,
A negative pressure area is created on the opposite side. Fuel fluid flows into the negative pressure region from the outside (arrow β).

The motion vector of the fluid from the slit (3) and the motion vector of the fuel fluid from the outside are combined to form a pipe (
1) A fluid flow is formed that advances toward the side.

The fluid stream is gradually narrowed in diameter and given a radial vector. This radial vector is converted into a turning vector, which together with the straight vector produces a spiral motion.

Of course, the present invention is not limited to the example shown in FIG. There are no particular limitations on the structure as long as a Coanda spiral flow can be generated and maintained. Furthermore, in the nozzle device of the present invention, since the pressurized fluid and the solid fuel particles do not mix turbulently, collision with the inner wall of the pipe is also suppressed. Therefore, it is not necessary to use a particularly hard material for the tube and its inner wall, as long as it has a heat resistance that can be used in a combustion furnace.

The Coanda spiral flow generating section of the nozzle device of this invention has an annular slit (3) as shown in FIG.
The cylindrical tube (2) is not only formed into a cone shape straight from the side, but also formed into a cone shape from the annular slit side through the cylindrical portion (10) as shown in FIGS. 2 and 3. It may be something that has been done.

In addition, as shown in Figure 3, the solid fuel particles are introduced into the inlet pipe (
11), the fluid may be introduced separately from the fluid flowing in along the streamline β.

In the nozzle device used in this invention (see Figure 1)
, for example, when the inclination angle of the cylindrical tube (2) is 0, tanθ is 1
It is preferable to set the ratio to about 1/4 to 1/8. Moreover, it is preferable that the ratio of the inner diameters of the conduit and the cylindrical tube is about 1/2 to 115.

When using the nozzle device of the present invention, there are no particular limitations on the type or construction of the combustion furnace.

It can be used with either vertical or horizontal burner flame systems. The nozzle device of the present invention can be used for combustion furnaces of various shapes such as cylindrical, cubic, and others.

One or more nozzle devices can be installed in the combustion furnace together with appropriate auxiliary means such as a reflector and gas circulation means. For example, in a cylindrical combustion furnace or heating furnace, burner flame is emitted from the bottom, and fuel fluid is ejected toward the center of the cylinder from multiple nozzle devices installed radially from the center line of the cylinder. You can also make them collide with each other. By doing this,
The fuel supplied by the spiral motion can diffuse into the combustion zone and improve combustion efficiency.

Alternatively, a plurality of nozzle devices of the present invention may be provided in a direction perpendicular to the combustion furnace.

The device of this invention and the combustion furnace using it as described above have the following features:
For example, COM, which is a mixture of coal and petroleum that has been ground to a fine powder with a diameter of 0.1#1I11 or less, and CWM, which uses water instead of petroleum, contains solid fuel particles such as coal or coke. Any suitable fuel fluid can be used. As the pressurized fluid, appropriate liquids such as oil and water, or gases such as air, combustion furnace circulating gas, natural gas, and LNG can be used.

The particle size of the solid used as fuel depends on the capacity and structure of the combustion furnace, but from the viewpoint of forming a fundus spiral flow, it should be 1/3 or less of the pipe diameter of the nozzle device,
The mixing ratio of solid particles and fluid is preferably 10 or less.

The pressure number J of the pressurized fluid of the nozzle device is 2 to 3 in 10.
It is preferable to set it to about /ct/lG.

By using such a nozzle device, it is possible to not only efficiently supply fuel fluid at high speed, but also to effectively suppress collisions between solid fuel particles and the inner wall surface of the device such as the pipe line. Become.

[Brief explanation of drawings]

FIG. 1, FIG. 2, and FIG. 3 are sectional views showing essential parts of an example of a nozzle device of the present invention. The numbers in the figure indicate the following.

Claims (10)

[Claims] (1) Pressurized fluid is introduced into the cylindrical pipe (2), which is connected to the end face of the pipe line (1) so as to be equal to the pipe diameter, and whose diameter gradually increases in the opposite direction to the connecting face. An annular slit (3) for feeding is formed, a wall surface (4) is smoothly curved from the slit (3) toward the pipe line (1), and the pipe line (1) is a cylindrical pipe. The opposite end face has a fuel fluid inlet (
5), and further includes means for supplying pressurized fluid to the slit (3) and means for supplying fuel fluid to the fuel fluid inlet (5); 1. A nozzle device for a combustion furnace, comprising: a pipe section for transferring fuel fluid to a nozzle outlet by Coander spiral flow; and a nozzle section for discharging fuel fluid into a combustion furnace. (2) A nozzle device for a combustion furnace according to claim (1), wherein the interval between the slits (3) is adjustable. (3) A nozzle device for a combustion furnace according to claim (1), wherein a pressurized fluid distribution chamber is provided between the slit (3) and the pressurized fluid supply means. (4) Pressurized fluid is introduced into the cylindrical pipe (2), which is connected to the end face of the pipe line (1) so as to be equal to the pipe diameter, and whose diameter gradually increases in the opposite direction to the connecting face. An annular slit (3) for feeding is formed, a wall surface (4) is smoothly curved from the slit (3) toward the pipe line (1), and the pipe line (1) is a cylindrical pipe. The opposite end face has a fuel fluid inlet (
5), and further includes means for supplying pressurized fluid to the slit (3) and means for supplying fuel fluid to the fuel fluid inlet (5); A combustion furnace characterized by using a nozzle device comprising: a pipe section for transferring fuel fluid to a nozzle outlet by Coander spiral flow; and a nozzle section for discharging fuel fluid into the combustion furnace. (5) A combustion furnace according to claim (4), wherein a plurality of nozzle devices are provided in the combustion furnace. (6) A combustion furnace according to claim (5), wherein the nozzle devices are provided so that the fuel fluids discharged from the nozzle portions of the plurality of nozzle devices collide with each other. (7) A combustion furnace according to claims (4) to (6), using COM or CWM as fuel. (8) A combustion furnace according to claims (4) to (6), which uses coal or coke as fuel. (9) A combustion furnace according to claims (7) to (8), in which heavy oil or water is used as the pressurized fluid. (10) A combustion furnace according to claims (7) to (8), in which air is used as the pressurized fluid.