JPH0798106A - Combustion equipment - Google Patents

Abstract

PURPOSE:To suppress the production of Nox and obtain a combustion gas of a high temperature without unburned combustibles, without pre-heating air even for a combustor for liquid fuel. CONSTITUTION:A Venturi element 7 to form a Venturi is internally fitted into a duct for air, and at the same time, a liquid fuel outlet hole 6a is provided at a throat part 8 of the duct which is constituted of the Venturi element 7. Then, at the leading end part on the downstream side of the Venturi element 7, a hole of which the leading end is opened in a combustion chamber 2 is provided in the axial direction. At the same time, a communicating hole 12 which communicates with the hole is opened on the downstream side of the throat part 8 of the Venturi element 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustor for obtaining high temperature combustion gas.

[0002]

2. Description of the Related Art It is desirable that the combustion gas obtained in a combustor is free of pollutants, that is, Nox and unburned substances, and is completely burned to have low residual O ₂ . By the way, a conventional combustor of this type mixes air and fuel at a concentration within an explosion limit range, ignites this by means such as air sparks to form a flame, and then mixes the air and fuel. I try to burn the air continuously.

[0003]

However, in the case of liquid fuel, since it is dispersed in the form of droplets, a high temperature part is partially generated during combustion, and a considerable amount of Nox is generated. . In order to suppress the generation of Nox, it was necessary to mix liquid fuel into preheated air and burn it as a pre-evaporated / pre-mixed air-fuel mixture.

The present invention has been made in view of the above, and even in the case of a combustor for liquid fuel, the generation of Nox is suppressed without preheating the air, and a high-temperature combustion gas containing no unburned matter is generated. It is an object of the present invention to provide a combustor that can be obtained.

[0005]

In order to achieve the above object, the combustor according to the present invention has a venturi body 7 forming a venturi inside the air passage pipe and the venturi body 7 The liquid fuel outlet hole 6a is provided in the throat portion 8 of the flow path pipe configured as described above, and a hole having a tip opening to the combustion chamber 2 is provided in the axial direction at the downstream end of the venturi body 7, Communication hole 12 communicating with
Is opened on the downstream side of the throat portion 8 of the venturi body 7. Further, a gas fuel outlet hole 6b is provided adjacent to the liquid fuel outlet hole 6a in the air passage. Further, the venturi body 7 is composed of a base end side member 7a made of metal and a tip end side member 7b made of ceramics, and a heat insulating material 9 is interposed at a joint portion of both members. Further, a hole provided at the axial center of the venturi body 7 is provided over the entire length thereof, and an observation member such as a frame eye 11 is provided on the base end side of the venturi body 7.

[0006]

[Operation] Liquid fuel is supplied from the liquid fuel outlet hole 6a to the throat portion 8 of the flow path pipe, and is dispersed in the air accelerated in this portion in the form of droplets and burned in the combustion chamber 2. It At this time, the pressure on the downstream side of the throat portion 8 becomes lower than that on the combustion chamber 2, and the combustion gas in the combustion chamber 2 is returned to the downstream side of the throat portion from the communication hole 12 through the hole of the venturi body 7. The high-temperature recirculated combustion gas heats the liquid fuel droplets supplied to the throat portion 8 to pre-evaporate the liquid fuel.
Premixed.

[0007]

EXAMPLE An example of the present invention will be described with reference to FIG. In the figure, 1 is a combustor, and 2 is a combustion chamber connected to the tip side of the combustor 1. Reference numeral 3 denotes an outer cylinder of the combustor 1, and the outer cylinder 3 has a cylindrical shape with a base end closed by a cover plate 4, and a tip end portion of the outer cylinder 3 is formed in an expanded shape. An air inlet pipe 5 is opened at the base end side of the outer cylinder 3, and a liquid fuel outlet hole 6a and a gas fuel outlet hole 6b are axially displaced from the air inlet pipe 5 toward the tip side, and A plurality of them are provided in the circumferential direction. Each fuel outlet hole 6a,
6b is designed to uniformly flow in from the circumferential direction through an annular fuel reservoir provided outside the outer cylinder 3.

Inside the outer cylinder 3, there are concentrically arranged venturi bodies 7 whose both axial sides are tapered at positions facing the liquid and gas fuel outlet holes 6a and 6b, respectively.
The venturi body 7 forms an annular throat portion 8 at the openings of both fuel outlet holes 5 and 6. The venturi body 7 has a base end member 7a whose one end is fixed to the cover plate 4 side.
And the tip side member 7 screwed to the base side member 7a.
It consists of b and. A heat insulating material 9 such as ceramics fiber is interposed in the screw connection portion of the end members 7a and 7b.

A through hole 10 is provided in the axial center of the venturi body 7 in the axial direction, and a frame eye 11 fixed to the outside of the cover plate 4 is connected to the base end side of the through hole 10. At 11, the interior of the combustion chamber 2 can be seen through the through hole 10. A communicating hole 1 communicating with the through hole 9 is formed in the tapered portion of the tip side member 7b of the venturi body 7.
2 are provided radially. Further, the end of the tip side member 7b of the venturi body 7 is opened in the combustion chamber 2.
A heat insulating material 13 is fixed inside the combustion chamber 2, and an initial ignition rod 14 is provided at the base end of the combustion chamber 2.

The operation of the above configuration will be described. While supplying air from the air inlet pipe 5, liquid fuel is supplied from the liquid fuel outlet hole 5. The flow velocity of the air in the combustor 1 is increased in the throat portion 8 composed of the Venturi body 7, and since the fluid fuel is supplied to the throat portion 8, the liquid fuel drops into the high speed air. Are dispersed and flow to the combustion chamber 2 side, and are ignited by the initial ignition rod 14 and burned.

At this time, since the pressure on the downstream side of the throat portion 8 is lower than that of the combustion chamber 2 due to the Venturi effect, the hot combustion gas in the combustion chamber 2 has a through hole provided in the axial center of the venturi body 7. 10, the fuel is returned to the downstream side of the throat portion 8 through the communication hole 12, and the fuel passing therethrough is mixed with the air-fuel mixture dispersed in the form of droplets.

As a result, the fuel dispersed in the form of liquid droplets that has passed through the throat portion 8 is vaporized into a pre-evaporated / pre-mixed state, and smooth combustion is continued in the combustion chamber 2.

When the liquid fuel has a high evaporation temperature like heavy oil and it is difficult to ignite first, the gaseous fuel is used only at the start. In this case, at the time of start, the gaseous fuel is supplied from the gaseous fuel outlet hole 6b and mixed with the air,
The initial ignition rod 14 ignites. The combustion is continued in the combustion chamber 2, and when the combustion gas in the combustion chamber 2 recirculates to the downstream side of the throat portion 8, the fuel gas is switched to the liquid fuel.

When using this combustor 1, 1500 ° C.
In the case of the combustion gas of Nox, the generation amount of Nox is 2 in terms of 0% oxygen.
It became about 0 ppm. Since the tip portion 7b of the venturi body 7 is exposed to high temperature, it is usually made of heat-resistant silicon carbide, but any ceramic capable of withstanding high temperature and thermal shock may be used. The base end member of the Venturi body 7 is made of metal. The heat insulating material 9 interposed between the two members 7a and 7b may be any material as long as it shields heat from the tip side member 7b and buffers the strain due to the difference in expansion coefficient. A ceramic fiber that is compression bonded is used.

The through hole 10 provided at the axial center of the venturi body 7 does not necessarily have to be provided over the entire length thereof, but only the tip side member 7b side is provided so that the combustion gas on the combustion chamber 2 side recirculates from the communication hole 12. You may do it. In this case, the flame eye 11 for observing the inside of the combustion chamber 2 is provided at another place.

[0016]

According to the present invention, even in the case of a combustor for liquid fuel, the generation of Nox can be suppressed and high-temperature combustion gas free of unburned matter can be obtained without preheating the air. .

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Combustor, 2 ... Combustion chamber, 3 ... Outer cylinder, 4 ... Lid body, 5 ... Air inlet pipe, 6a ... Liquid fuel outlet hole, 6b ... Gas fuel outlet hole, 7 ... Venturi body, 7a ... Base end side Member, 7b ... Tip member, 8 ... Throat portion, 9, 13 ... Insulation material, 10 ...
Through hole, 11 ... Flame eye, 12 ... Communication hole, 14 ... Initial ignition rod.

Claims (4)

[Claims] 1. A venturi body 7 forming a venturi is internally provided in an air flow pipe, and a liquid fuel outlet hole 6a is provided in a throat portion 8 of the flow pipe constituted by the venturi body 7. A hole having a tip opening to the combustion chamber 2 is provided in the downstream end of the venturi body 7 in the axial direction, and a communication hole 12 communicating with this hole is opened downstream of the throat portion 8 of the venturi body 7. Combustor characterized by having done. 2. The fuel device according to claim 1, wherein a gas fuel outlet hole 6b is provided adjacent to the liquid fuel outlet hole 6a in the air flow passage. 3. The venturi body 7 is composed of a base end side member 7a made of metal and a tip end side member 7b made of ceramics, and a heat insulating material 9 is interposed at a joint portion of both members. The combustor according to 1 or 2. 4. The hole provided in the axial center of the venturi body 7 is provided over the entire length thereof, and an observation member such as a frame eye 11 is provided on the base end side of the venturi body 7. The combustor according to 3.