JP2774667B2 - Mixer - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a mixer. More specifically, the present invention relates to a mixer suitable for premixing fuel and air in a narrow space.

(Prior Art) As a conventional mixer, a venturi mixer that blows air from a nozzle and sucks and mixes gas by kinetic energy of the jet flow is generally used. This mixer is used in various industrial gas burners as a mixer for a premixed gas burner.

On the other hand, the present inventors, in developing a combustor for a low NOx gas turbine, segmented and combined a small catalytic combustion unit and a premixed gas supply unit that have been industrially practically used,
The idea was to construct a single large burner and keep the catalyst temperature below the allowable temperature limit of the catalyst by the combined combustion of catalytic combustion and gas phase combustion to prevent the catalyst from deteriorating and raise the combustion gas temperature at the combustor outlet. . However, in this combustor, since the pressure loss in the catalytic combustion section is large, a mixer that is small in size and capable of premixing without increasing the pressure loss is required for practical use of the combustor.

(Problems to be Solved by the Invention) However, for example, a venturi mixer for the purpose of reducing pressure loss requires a large number of venturi sections in order to obtain uniform mixing, and the structure becomes complicated, resulting in high production cost. There is a problem. In other methods, the pressure loss becomes considerably large, which is not preferable in a case where mixing is to be performed by pressurized air from a compressor as in a gas turbine combustor. In addition, the apparatus becomes large and expensive, but there is a problem.

That is, it is difficult to apply the conventional mixer as a premixer for a small catalytic combustion section due to a problem in manufacturing and a problem in pressure loss.

An object of the present invention is to provide an inexpensive mixer having a simple structure with little pressure loss.

(Means for Solving the Problems) In order to achieve such an object, the mixer of the present invention comprises a first mixer.
And an outer cylinder surrounding the inner cylinder and forming a flow passage for the second fluid between the inner cylinder and the inner cylinder.
Concavities and convexities formed by alternately and continuously providing ridges and valleys in the outer peripheral portion of the inner cylinder in the circumferential direction are formed by the inner cylinder itself, and the ridges are formed in the downstream of the flow direction of the second fluid. The outer diameter of the crest is gradually increased toward the bottom, and an outlet of the concavity and convexity of the inner cylinder is provided at the end of the concavity and convexity formed by continuously providing the crests and the valleys of the inner cylinder alternately. A wall surface to be closed is provided, and the injection port of the first fluid is opened at a position corresponding to each crest of the wall surface.

Further, the mixer of the present invention is arranged so that an igniter is penetrated in a radially central portion of the inner cylinder, and at a position downstream of the wall surface, a first fluid mixed downstream of the wall surface. A burner function for igniting a mixed fluid with the second fluid is provided.

The mixer according to the present invention may further comprise a flow path for flowing the second fluid at a radially central portion of the inner cylinder and an outlet formed on a wall surface of the inner cylinder, And the second fluid is blown out immediately downstream of the wall surface.

In the mixer of the present invention, a plurality of inner cylinders are provided in one outer cylinder.

(Operation) Therefore, the second fluid flows from the trough to the negative pressure portion generated after the crest, that is, downstream, and collides with the first fluid ejected from the wall surface of the crest to be mixed. At this time, since the second fluid is gradually divided by the ridges gradually increasing in the flow direction, the second fluid is accelerated without greatly increasing the pressure loss, and the first fluid is reduced by the negative pressure formed downstream of the ridges. It easily goes around in front of the injection port to mix and diffuse the first fluid and the second fluid.

(Example) Hereinafter, the configuration of the present invention will be described in detail based on an example shown in the drawings. This embodiment is implemented as a premixer of a combustor in which catalytic combustion and gas phase combustion are combined.

FIG. 1 shows a schematic diagram of a combustor for a catalytic combustion type gas turbine to which the mixer of the present invention is applied. The combustor for a catalytic combustion type gas turbine of this embodiment has a burner section 1 in which a premixed gas supply section 4 and a catalytic combustion section 3 are arranged in parallel, and a premixed combustion section formed downstream of the burner section 1. The premixed gas from the premixed gas supply unit 4 is subjected to lean premixed combustion using the catalytic combustion gas from the catalytic combustion unit 3 as a flame holding source.

Although not shown, the combustor usually has a double cylinder structure of a casing (not shown) and a liner 11, and is supplied from the gas turbine side to an air flow path formed between the liner and the casing. And a burner unit 1 composed of a set of a premixed air supply unit 4 and a catalytic combustion unit 3;
It is provided so as to supply to the premix combustion unit 2 inside the liner 11 through a cooling air hole (not shown) and a bypass passage (not shown) of 11.

Further, the premixed combustion section 2 is surrounded by ceramics, and the presence of a high-temperature wall that hardly requires cooling makes it possible to minimize heat loss in the premixed combustion section 2 in a state where gas phase combustion is unlikely to occur, thereby achieving uniform and complete combustion. It is provided so that For example, as shown in the figure, the metal cylinder 11a is used as a structural material,
When the inner wall 11b is made of ceramics, a stable combustion field having a more uniform temperature can be obtained. in this case,
The ceramics may be tile-like or fibrous. Further, the entire liner can be formed of ceramics.

The premixed gas supply unit 4 includes, for example, an air supply pipe 20 opened in a casing and a fuel nozzle 21. The premixed gas supply unit 4 has a predetermined concentration based on compressed air distributed according to an opening area ratio and fuel ejected from the fuel nozzle 21. Is provided so as to obtain a pre-mixed gas. A swirler 22 is provided at the outlet of the air supply pipe 20 that constitutes the premixed gas supply unit 4 so that the premixed gas is injected toward the flow of the catalytic combustion gas to diffuse and mix to some extent with the catalytic combustion gas. It is provided in.

The catalytic combustion section 3 is preferably formed by filling a tube segment with a catalyst 18, and is provided with a premixer 30 upstream thereof. For example, catalyst 18 and baffle plate 40
And a pre-mixer 30 composed of an air supply pipe 31 and a combustion nozzle 32.

As shown in FIG. 2, the premixer 30 forms an inner cylinder or fuel nozzle 32 through which a first fluid such as fuel flows, and a flow path through which a second fluid such as air flows between the inner cylinder 32. A petal comprising an outer cylinder or an air supply pipe 31 and having ridges 34 gradually increasing in outer diameter in the flow direction of air and valleys 33 parallel to the flow direction of air alternately provided at regular intervals in the circumferential direction. Fuel nozzle 32
And an air supply pipe 31 surrounding the same, so that the air flowing through the valley 33 flows into a negative pressure section formed downstream of the peak 34 to mix the air and the fuel. . The fuel injection port 35 of the fuel nozzle 32 is opened on the wall surface 36 of the peak 34 intersecting with the flow of air, and is injected in the same direction as the flow of air.

The second fluid air flows into the valleys 33 or peaks of the fuel nozzle 32.
It flows through a flow path surrounded by the side wall surface of the air supply pipe 31 and the air supply pipe 31.
The peak 34 gradually increases its outer diameter to form a valley 33 as if dividing the air flow path. Therefore, the air flow is gradually accelerated without greatly increasing the pressure loss, and is divided along the outer peripheral surface of the fuel nozzle 32. Then, when the air flowing between the air supply pipe 31 and the fuel nozzle 32 reaches the downstream side of the peak portion 34, due to the negative pressure generated downstream of the fuel nozzle 32 and the flow interference effect resulting therefrom, It flows so as to be caught in the entire surface of the fuel nozzle 32, that is, downstream of the fuel ejection port 35. As a result, the fuel and air are uniformly mixed. In this case, the intensity of the mixing can be adjusted by adjusting the diameter of the fuel ejection port 35 and the area of the entire surface of the fuel nozzle 32.

An opening 38 is provided at the center of the fuel nozzle 32 to provide an ignition torch.
37 is provided to allow the premixer 30 to also have a function as a burner.

A baffle plate 40 is provided downstream of the catalyst 18, that is, at the outlet of the catalytic combustion section 3. This baffle plate 40
Is formed, for example, of a cross-shaped plate that blocks the flow of the catalytic combustion gas, and generates a gentle swirling flow that does not collide with each other from the notch between the pieces projecting in the radial direction toward the central negative pressure portion. This gentle swirling flow is supplied to the surrounding premixed gas supply unit 4.
Part of the lean premixed gas injected from the nozzle is involved to achieve appropriate mixing.

The above embodiment is an example of a preferred embodiment of the present invention, but the present invention is not limited to this, and various modifications can be made without departing from the spirit of the present invention. For example, FIG. 1 shows an application example in which an ignition torch 37 is installed at the center of the fuel supply unit and has a function as a low NOx burner capable of uniform combustion. The torch 37 is not necessary, and a pipe for flowing air diverted from the air flow path between the air supply pipe 31 and the fuel nozzle 32 is provided in the space of the ignition torch 37 to further improve the mixing property. You can also.

FIG. 1 shows an example of application in an axisymmetric air flow. However, there is no particular need to stick to an axisymmetric shape, and the outer shape and the necessity of the fuel nozzle (inner cylinder) 32 may be adjusted according to the shape of the flow path. For example, the inner shape of the air supply pipe (outer cylinder) 31 may be changed.
In this case, it is important to gradually increase the outer diameter in the downstream direction of the flow, and to provide a peak portion 34 and a valley portion 33 in the outer shape so as to cut off the flow path.

Further, there is no need to be particular about the size of the flow path. In this case, a plurality of fuel nozzles 32 may be arranged in one air supply pipe 31 to improve the mixing property.

Further, in the present invention, the outer cylinder and the inner cylinder are configured to have a cylindrical feeling, but the invention is not particularly limited to this, and the cross section is short,
It may be configured as a triangle or the like.

Further, in the present embodiment, the fluid to be mixed is fuel and fuel air. However, other fluids may be used, and air may flow to the inner cylinder and fuel may flow to the outer cylinder.

(Effects of the Invention) As is apparent from the above description, the present invention provides an inner cylinder through which a first fluid flows, and a flow path surrounding the inner cylinder and through which a second fluid flows through the inner cylinder. Formed in the outer peripheral portion of the inner cylinder, irregularities formed by alternately continuously providing peaks and valleys in the outer peripheral portion of the inner cylinder are formed in the inner cylinder itself, and the peaks are The outer diameter of the crest is gradually increased toward the downstream in the flow direction of the second fluid, and the crest and the trough of the inner cylinder are provided alternately and continuously. Since a wall for closing the outlet of the concave and convex portion of the inner cylinder is provided and the injection port of the first fluid is opened at a position corresponding to each crest of the wall, the pressure loss of the air flow is greatly increased. Without this, the fuel supply can be diffused into the air stream. Further, since the peaks and valleys are provided on the outer shape so as to divide the air flow path between the outer cylinder and the inner cylinder, the pressure loss is further reduced and the air is supplied to the fuel supply section. It can easily go around to the front.

Due to these effects, the fuel and air are uniformly mixed without increasing the pressure loss.

Also, the structure can be manufactured simply and inexpensively by pipe expansion and welding.

Further, by providing an igniter at the center, combustion in a state where fuel and air are uniformly mixed can be obtained, and a role as a low NOx burner can be provided.

[Brief description of the drawings]

FIG. 1 is a central longitudinal sectional view showing a specific example of a burner portion of a combustor for a catalytic combustion type gas turbine to which the mixer of the present invention is applied. 2 (A) and 2 (B) are a central longitudinal sectional view and a partially cutaway front view showing an embodiment of a premixer. 30 premixer, 31 air supply pipe (outer cylinder), 32 combustion nozzle (inner cylinder), 33 valley section, 34 ridge section, 35 injection port, 36 wall .

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Noboru Hisamatsu 2-24-141 Ashina, Yokosuka City, Kanagawa Prefecture (72) Inventor Hiroshi Ishikawa 1-5336-3 Hibarigaoka, Zama City, Kanagawa Prefecture (72) Inventor Toru Yamanaka Osaka Prefecture Kansai Electric Power Co., Inc., 3-2-2 Nakanoshima, Kita-ku, Osaka-shi (72) Inventor Mikito Saiga 3-2-2, Nakanoshima, Kita-ku, Osaka-shi, Osaka Kansai Electric Power Co., Inc. (72) Inventor: Masahiro Okahata Osaka Kansai Electric Power Co., Inc. 3-2-2 Nakanoshima, Kita-ku, Osaka-shi, Japan (72) Inventor Toshiaki Hasegawa 2-53-1, Shirite, Tsurumi-ku, Yokohama-shi, Kanagawa Prefecture Inside Japan Furness Industry Co., Ltd. (72) Toshifumi Hoshino 2-53-1, Shirite, Tsurumi-ku, Yokohama-shi, Kanagawa Prefecture Inside Japan Furness Industrial Co., Ltd. (58) Field surveyed (Int.Cl. ⁶ , DB name) F23R 3/20 F23R 3/30 F23R 3 / 40

Claims (4)

(57) [Claims] An inner cylinder for flowing a first fluid, and an outer cylinder surrounding the inner cylinder and forming a flow path for flowing a second fluid between the inner cylinder and the inner cylinder. Concavities and convexities formed by alternately and continuously providing peaks and valleys in the outer peripheral portion in the circumferential direction are formed by the inner cylinder itself, and the peaks are formed in the downstream direction in the flow direction of the second fluid. The outer diameter of the ridge is gently increased, and a wall that closes the outlet of the ridge of the inner cylinder is provided at the end of the ridge and groove formed by alternately providing the ridge and the valley of the inner cylinder. A mixer, characterized in that the first fluid injection port is opened at a position corresponding to each crest of the wall surface. 2. A first fluid and a second fluid, which are arranged at a radially central portion of the inner cylinder so as to penetrate an igniter and are mixed downstream of the wall at a position downstream of the wall. The mixer according to claim 1, further comprising a burner function for igniting a mixed fluid with the mixture. 3. The second cylinder is provided at a central portion in a radial direction of the inner cylinder.
And forming an outlet in the wall surface of the inner cylinder, and blowing the second fluid through the wall surface of the inner cylinder and immediately downstream of the wall surface. Item 7. The mixer according to Item 1. 4. The mixer according to claim 1, wherein a plurality of inner cylinders are provided in one outer cylinder.