JPS63243612A - Radiant tube burner - Google Patents

Abstract

PURPOSE:To perform stable complete combustion, by a method wherein, in a title burner for burning liquid fuel, a primary air swirler vane is formed on the outer periphery of a flame dispersion type nozzle, and the nozzle is connected to a foam producer, from which pressurized gas, liquid fuel, and water can be supplied, through a conveyance pipe. CONSTITUTION:Gas, e.g. air, steam, inactive gas, combustion exhaust gas, liquid fuel, and water, all being pressurized to the same pressure, are fed through feed ports 4-6 to a foam producer 7. The foam producer 7 produces emulsion foams, which are fed to a flame dispersion type nozzle 3 and are injected in a combustion cylinder 2. This injection forces pressurized gas in the foam to be rapidly expanded in a combustion chamber for rupture to produce fine emulsion particles. Meanwhile, a primary air C1 coming through an inflow port 9 is swirled by means of a primary air swirler vane 10 and fed to the combustion cylinder 2, where the primary air is agitated together with emulsion particles for primary combustion. This constitution provides combustion approximately similar to fuel, and provides stable complete combustion.

Description

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, a nozzle of a liquid fuel burner faces concentrically into a combustion cylinder provided in a radiant tube, and the liquid fuel ejected from the liquid fuel burner is connected to the liquid fuel burner. It relates to a radiant tube that performs primary combustion by primary air supplied through an annular space between the combustion tube and secondary combustion by secondary air supplied through an annular space between the combustion tube and the radiant tube, More specifically, the present invention relates to a radiant tube for liquid fuel that burns liquid fuel such as heavy oil, kerosene, naphtha, etc. as fine particles.

[Conventional technology]

The conditions required for such a radiant tube are heating so that the surface temperature of the tube is uniform, stable combustion without the generation of unburned carbon during burner combustion, and reduction of NOx generation. That's true. However, when liquid fuel is burned in a radiant tube, local heating occurs because the atomized droplet system of the liquid fuel is large.
Currently, gas fuel is used because the conditions required for radiant tubes cannot be met due to problems such as unburned carbon being generated and NOx levels becoming high.

[Problem that the invention seeks to solve]

The present invention atomizes liquid fuel, atomizes it with a flame dispersion nozzle, and performs high-load combustion with a swirling flow of secondary air to achieve good and stable combustion, resulting in combustion similar to that of gas fuel. This provides a radiant tube burner that can.

[Means for solving problems]

For this purpose, according to the present invention, primary air swirl vanes are formed on the outer periphery of a nozzle configured as a flame dispersion type nozzle, and the nozzle and pressurized gas (air, steam, inert gas, combustion exhaust gas), liquid fuel and a foam generator capable of supplying water are connected via a transfer pipe.

〔Example〕

In FIG. 1, a liquid fuel burner l has a flame dispersion type nozzle 3 protruding into a combustion tube 2 provided concentrically around the burner l, and pressurized gas (air , steam, inert gas, flue gas), liquid fuel and water (4+5+6), and behind the combustion tube 2 there is a primary foam generator 7 which likewise surrounds the burner concentrically. An air supply cylinder 8 is formed continuously, and four primary air inlets 9 are bored around the circumference thereof. Furthermore, on the tip of the liquid fuel burner l, 15
A primary air swirling vane 10 having an angle of ~,60° is fixed via a holding cylinder 11, and a radiant tube 12 is provided on the outer periphery of the combustion cylinder 2 and the primary air supply cylinder 8. The feed tube and the radiant tube are closed off at the end wall 15 via respective flanges 13, 14, through which the liquid fuel burner extends. Further, a primary air supply cylinder 86 is connected to the rear of the radiant tube 12, and one end of the pilot burner 17 faces the flame dispersion type nozzle 3 through the end wall 15.

Next, the foam generator 7 for atomizing the liquid fuel has a disk 19 having a circular recess 18 and a diameter gradually decreasing from the diameter corresponding to the recess, as shown in FIGS. 2 and 3. A foam generation chamber 22 is defined by lighting a conical hole 20 in the center and coaxially fitting a cylinder 21 having the same diameter as the disk. Disk 1'9 closer to circle 1321
31i in the tangential direction of the recess 18, the blowing fins 23, 24, 25 for pressurized gas (air, steam, inert gas, combustion exhaust gas), liquid fuel and water are connected to the central axis x
- a disk 19' and a circle f arranged on one plane Y-Y perpendicular to X and forming a conical foam generation chamber 22;
121 is a housing 26 with a fitting joint method.
In this case, the disk 19 is fixed to the plug 28 via the inner sleeve 27 and the water injection groove 25 cut in the disk
The foam generation chamber 2 is carried through the plug.
The pressurizing housing (air, steam, inert gas, combustion exhaust gas) blowing groove 23 and liquid fuel blowing groove 24 of the front pillar are connected to the water supply pipe 29 extending coaxially to the housing. It communicates with the pressurized gas supply port 4 and the liquid fuel supply port 5 . Further, a transfer pipe 30 is fitted into the center of the conical hole 2o of the cylinder 21, and a flame dispersion type nozzle 3 is fitted onto the plain end of the transfer pipe. It extends concentrically to surround it.

[Effect]

Now, the supply port 4 provided in the housing 26 of the foam generator 7
+5 +6 Gas (air, steam, inert gas, combustion exhaust gas) pressurized to the same pressure in the pressure range of 3 to 5 kg/c-, liquid fuel and water are supplied, disc 1
Through the blowing grooves 23, 24, and 25 carved in 9,
When the foam is blown into the foam generation chamber 22 in the tangential direction, the oil and water emulsify while swirling and form an emulsion.
As shown in Fig. 5, pressurized gas (air, steam,
A large number of emulsion foams containing inert gas (inert gas, combustion exhaust gas) are formed, and these foams are then swirled through the conical hole 20 through the transfer pipe 30 and from the flame dispersion nozzle 3 into the combustion tube 2. gush. As a result, the foam rapidly expands and ruptures due to the difference between the pressure of the pressurized gas (air, steam, inert gas, combustion exhaust gas) in the foam and the pressure in the combustion chamber, resulting in fine emulsion particles. Since the fine emulsion particles contain water, when they are burned, the water particles cause micro-explosion and become even more fine.

In this way, the liquid fuel spouted into the combustion tube 2 flows through the inlet 9
The combustion gas is stirred together with the primary air Cλ which flows into the primary air swirler IO and is swirled by the secondary air swirl vane IO, and performs reduction-fire combustion under high load, and this fire combustion gas is ejected from the combustion tube 2. In this case, the tip of the combustion tube 2 and the primary air swirl vane 10
The distance from the end face (gas nozzle position) to lOO ~ 500
It is set at a position that satisfies each condition (NOx combustibility, etc.) within the range of The secondary air Ca (90-50%) is burned f
Flowing through the annular passage between the jrJ2 and the radiant tube 12 along the inside of the tube while cooling the combustion cylinder,
- Secondary combustion occurs sequentially at the interface of combustion gas without local heating.

〔Effect of the invention〕

From the above, the radiant tube burner according to the present invention is equipped with a flame dispersion nozzle, a transfer pipe, and a foam generator, and the primary air swirl vanes are formed on the outer periphery of the nozzle, so that NOx can be reduced. At the same time, it is possible to perform good combustion without incomplete combustion and without generating unburned substances such as soot and carbon monoxide. Furthermore, the tube surface temperature, which is an important condition for radiant tube burners, can be made uniform in the circumferential direction by swirling the flame, and in the axial direction, the difference between the maximum and minimum temperatures in the furnace can be kept within 1506C. When the temperature inside the furnace is 950°C, the maximum tube temperature is also 1050°C or less, making it possible to extend the life of the radiant tube to a value that can withstand long-term use.

[Brief explanation of drawings]

FIG. 1 is an axial cross-sectional view of a radiant tube burner according to the present invention, FIG. 2 is a cross-sectional view passing through the central axis of the liquid fuel burner, FIG. 3 is a cross-sectional view of the foam generation chamber, and FIGS. 4 and 5. FIG. 2 is a diagram illustrating the generation of emulsion foam. DESCRIPTION OF SYMBOLS 1... Liquid fuel burner, 2... Combustion cylinder, 3... Flame dispersion type nozzle, 4... Pressurized gas (air, steam, inert gas, combustion exhaust gas) supply port, 5... Liquid fuel supply port, 6... Water supply port, 7... Foam generator, lO...
-Next air swirl vane, 12...Radiant tube, 1
9... Disk, 21... Cylinder, 22... Foam generation chamber, 30... Transfer pipe, Cz... - next air, Cm...
・Secondary air. Patent applicant: Japan Combustion System Co., Ltd. Mitsubishi Heavy Industries, Ltd.

Claims (1)

[Claims] A nozzle of a liquid fuel burner is arranged to face concentrically into a combustion cylinder provided in a radiant tube, and liquid fuel ejected from the liquid fuel burner is supplied through an annular space between the liquid fuel burner and the combustion cylinder. In a burner of the type in which primary combustion is performed by primary air supplied through the combustion tube and secondary combustion is performed by secondary air supplied through an annular space between the combustion tube and the radiant tube, a flame dispersion type nozzle is formed on the outer periphery of the nozzle. A primary air swirl vane is formed between the nozzle and the pressurized gas (air, steam, inert gas,
A radiant tube burner characterized in that a foam generator capable of supplying combustion exhaust gas), liquid fuel, and water is connected via a transfer pipe.