JPS5949403A - Method and device for combustion - Google Patents

Abstract

PURPOSE:To enable effective suppression of production of thermal NOX and an unburnt matter, such as CO, UHC, through uniformity of temperature distribution during combustion, and to improve combustion efficiency, by a method wherein fuel gas and gas containing oxygen are burnt within a block formed by an air-permeable solid having an enoughly high void volume. CONSTITUTION:Air-permeable solids 24, having a lower void volume than that of an air-permeable solid forming a combustion block 12, are connected to the upstream side and the downstream side of combustion gas of said block 12. A flow distributer 16 uniforms the flow of a mixed fuel MF and simultaneously disperses it uniformly, and combustion starts under condition in which the fuel is sealed in spaces in the air-permeable solid partitioned into the blocks 12. In which case, high-efficient heat exchange takes place, and the latent heat in combustion gas is converted into a large quantity of the solid radiation heat. In this case, by the effect of solid contact, low-temperature combustion gas is increased in temperature, the temperature of high-temperature combustion gas is suppressed, and temperature is leveled on the whole to provide uniform combustion, resulting in reduction in production of thermal NOX.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a combustion method and an apparatus thereof, and more particularly, the present invention relates to a combustion method and an apparatus for the same, and more particularly, the present invention relates to a combustion method and an apparatus thereof, and more particularly, to a combustion method and an apparatus for the same. °The port d1 obtains a uniform temperature distribution, suppresses the generation of nitrogen oxides (NOx), and unburned substances such as carbon oxides (CO) and unburned hydrocarbons (UIIC), and also suppresses the generation of unburned substances such as carbon oxides (CO) and unburned hydrocarbons (UIIC). This invention relates to a combustion method that can easily obtain combustion gas, and a combustion apparatus for carrying out the method.

When various fuels are burned to obtain high-temperature combustion gas and used as a heating source for a bowl or furnace, or as a heating source for a stove, etc., an air mixture consisting of a mixture of fuel and gas is generated. Generally, fuel is supplied under pressure from a burner (for example, a Schwanck burner) and ignited to perform flame combustion. However, in this so-called flame combustion, the combustion 411
・It is difficult to achieve uniform combustion. For this reason, there are locally high and low temperature areas in the flame, and harmful nitrogen oxides (NOx) are generated as byproducts during combustion, as well as carbon oxides (CO) and unburned Hydrocarbons (UUC) tend to be easily generated.

Therefore, as administrative emissions regulations are strengthened from the perspective of pollution prevention, there is a shift toward fuels with lower sulfur and nitrogen content, and
Efforts have been made to install smoke denitrification equipment and other measures to reduce NOx, but the current situation is that it is difficult to achieve the regulation value due to increased installation costs and technical problems.

Such so-called "thermal N0xJ" is generated by the reaction between nitrogen and oxygen in the air during fuel combustion, but as the combustion temperature increases, the reaction becomes more intense.
Therefore, it has been found that the amount of thermal NOx emissions is determined by the maximum temperature.

In normal flame combustion, the temperature distribution is not constant, so there are localized areas of high temperature (for example, 1400 degrees Celsius).
This is the cause of increased thermal NOx generation.

In addition, -carbon oxide (CO) and unburnt hydrocarbon (UII)
The occurrence of C) is also closely related to the combustion temperature of the combustion gas, and according to a catalytic combustion experiment using a catalyst described below, when the combustion temperature is 900°C or higher, 1,0, Ull It has been confirmed that [[] increases rapidly, and that c, o, and unc hardly occur at temperatures above 1000°C. In this way, thermal NOx and CO1UUC are associated with high humidity and combustion, so research on catalytic combustion methods using high-performance catalysts has recently been carried out to achieve uniform combustion in the high humidity region of 1000°C or higher. Is it possible to improve the photogeneration of NOx snow by doing it stably?
) We have a track record of significantly reducing this.

However, the bottleneck in applying the catalytic combustion method using this catalyst to combustion equipment for heat sources such as boilers, gas turbines, etc. is that the long-life catalyst [J
It has not yet been developed, and catalysts with similar performance would be extremely expensive, so the running cost of 1- is not worth the cost.

Furthermore, in conventional flame combustion, the high-temperature combustion gas obtained after the combustion reaction as a flame has finished is released into the atmosphere without its sensible heat being fully utilized as a heat source (that is, while still retaining a large amount of thermal energy). At present, gas is dissipated and discharged into the atmosphere, and the effective use of gas sensible heat remains an unresolved problem from the standpoint of energy conservation.

In view of the aforementioned problems, thermal NOx and CO
In search of a new combustion force method that can reduce and suppress the occurrence of , tlllc, etc., and also effectively draw out the sensible heat in the combustion gas and obtain high-temperature combustion gas, the inventor has made extensive research efforts. As a result, a so-called breathable solid with a sufficiently large porosity was used to construct a combustion block of 3ft, and a mixed fuel consisting of a mixture of gas and air was combusted in this combustion block. If the air-permeable solid has a large surface rtt (heat transfer area), as will be described later, the temperature of the adjacent gas (1) will be almost the same as that of the solid, while the temperature between the circular bodies will be the same due to the exchange of strong zero radiation. Because the temperature distribution is smoothed, combustion occurs uniformly, and as a result, the generation of thermal NOx is suppressed.Furthermore, unburned components come into contact with the fine wires of the permeable solid heated to high temperatures and are reburned, producing CO and U
It was found that the occurrence of IIC was also effectively suppressed.

Furthermore, as a result of combustion taking place in an air-permeable solid having the characteristics described below, the sensible heat contained in the combustion gas is converted into a large amount of radiant heat, resulting in extremely high combustion efficiency and the ability to easily burn high-temperature combustion gas. It was also found that it greatly contributes to energy saving.

Therefore, in the combustion method according to the present description, a mixed fuel consisting of a mixture of fuel gas and air is supplied to a combustion block made of an air-permeable solid having a sufficiently large porosity, and in this combustion block, the mixed fuel is Particularly, the combustion device i″f according to the present invention is characterized in that the combustion device i″f according to the present invention is characterized in that the combustion device i″f has an air permeability with a sufficiently large porosity on the opening side of the mixed fuel supply pipe that supplies the mixture of fuel gas and air. It is characterized by connecting combustion blocks made of solid.

In addition, the combustion device according to another invention of the present application includes, on the opening side of the mixture fuel supply pipe that supplies the d1 mixture of fuel gas and air,
A combustion block made of a permeable solid having a sufficiently large porosity is connected, and a permeable solid having a smaller porosity than the permeable solid constituting the block is connected to the combustion gas JJC outlet side of this combustion block. Features.

Furthermore, in the combustion device according to another invention of the present application, a gas permeable solid having a sufficiently large porosity is inserted through a gas permeable solid having a small porosity on the opening side of the mixed fuel supply pipe that supplies a mixture of fuel gas and air. A combustion block consisting of the above is connected, and a permeable solid having a lower porosity than the permeable solid constituting the block is connected to the combustion gas discharge side of the combustion block.

In addition, in the present invention, places,! Since the PI air-permeable solid occupies a very important weight, a general description of this air-permeable solid will be given before describing the preferred embodiments. Kimei III-! What is the so-called aeration 4'1 solid?
Defined as a solid medium made of heat-resistant materials such as metals and ceramics into shapes such as nets, honeycombs, and fibers to provide air permeability and an appropriate thickness of U f + Ti that transmits light and other heat rays. I can do it.

This is thought to be composed of a large number of focused fine wires or fine grains, and its substantial surface area is extremely large. Since the radiation emission ability of a solid is sufficiently higher than that of a gas, when the combustion gas is passed through the breathable solid,
When the sensible heat of the combustion gas comes into contact with a solid with an extremely large surface area, highly efficient heat exchange occurs, generating a large amount of solid radiant heat. A solid heat transfer conversion element having the above characteristics is called a breathable solid. Note that this breathable solid has a characteristic that even if heat is removed by heat exchange with the flow of combustion gas, the I knee At side is hardly affected.

The radiant heat emission state of the breathable solid S will be explained using the schematic diagram shown in FIG. 1. Since the breathable solid S has a thickness X in the direction of flow of the combustion gas G, the combustion gas・Convection heat transfer takes place within the layer
In curve C, ii <1' W, resulting in an 11 degree slope. The sensible heat of the combustion gas in the ancient layer χ1... '/) and single flow side (Z
), but part of this solid radiant heat is shielded and attenuated according to the thickness of the breathable solid S in the front and back direction, and as a result, most of the radiant heat J ( The gas G is injected to the second flow side (Y).

Next, the combustion method and its device according to the present invention will be explained first by citing preferred embodiments of the combustion device, with reference to accompanying drawings, and then the combustion method will be explained in relation to its effects. . FIG. 2 shows one embodiment of the combustion apparatus according to the present invention, in which a mixture of fuel gas (for example, combustible gas such as city gas, natural gas, furnace top gas, etc.) and air is shown. M1.' is supplied from a fuel supply source (not shown) and is delivered to the mixed fuel supply pipe 1o. In addition, if the combustion exhaust gas is sucked in from the combustion gas exhaust side using a suction fan, etc., the d^air combustion flow M
There is no need to supply F under pressure. The fuel gas MF may be mixed with air immediately before flowing into the block body described later.

In the figure, reference numeral 12 indicates a suitably three-dimensional block made of air permeable solid with sufficient porosity, and combustion of fuel takes place inside this block 12, as will be described later. , hereinafter referred to as a combustion block.

The hot air fuel supply pipe 10 has an elongated opening 14 as shown in the figure.
A combustion plotter 12 made of an air-permeable solid material with a large air gap skewer is connected to this opening side. In this case, between the opening 14 of the supply 'i' I O and the combustion block 12, there is a rectifying means 16 such as a rectifying grid formed by drilling a large number of pores in the ceramic plate 1-.
The hot fuel M r'' supplied under pressure from the supply pipe 1° is uniformly released by interposing the fuel.

Preferably, the fuel is then fed into the combustion block 12.

The porosity of the air permeable solid constituting this combustion block 12 is 99% or more (in other words).

It is preferable that the air-permeable solid material has a sufficiently large porosity (filling rate of 1% or less), and examples of breathable solids with a sufficiently large porosity include, for example, blocks made of a floc-like agglomeration of heat-resistant thin metal wires, or multiple layers of heat-resistant wire mesh. Laminated bodies and other porous objects made by foaming and solidifying ceramic materials into a pumice shape are suitably used.

In this case, if the air permeable solid has a porosity of R1 degree, then 1
The question is whether it can be said to be sufficiently large, but it is most appropriate to judge based on the optical thickness rather than expressing it by the mesh number as in the case of wire mesh. )'/iMeasurement of the optical thickness involves interposing a breathable solid material such as the object to be measured between the light source and the illuminance meter, and determining how much light is absorbed from the illuminance side. It is determined by considering the wire diameter and absorption coefficient of the thin metal wire. In the case of this example,
Suitable results were obtained by using an agglomerate of fine metal wires having an optical thickness in the range of 1 to 1 degrees depending on the size of the combustion block itself as the air permeable solid constituting the combustion block 12.

Furthermore, this combustion block 12 is surrounded by a fire-resistant heat insulating material 2o on its outer periphery, except for the upstream side where the mixed fuel flows in and the side of the 11th block 4ε where the combustion gas is discharged.
The structure is such that the escape of radiant heat from the outer periphery of the block 12 is blocked. However, this results in radiant heat being trapped within the block 12.

FIG. 3 shows another embodiment of the invention according to the present application, which basically uses the heat exchange device shown in FIG. Air permeable solid 22 with a smaller porosity than the air permeable solid composing the air permeable solid 22
are connected and arranged.

The porosity of this breathable solid 22 is preferably 90% to 95% or more (in other words, the filling rate is 10% to 5% or less). In the case of this embodiment as well, a rectifying means 16 such as a perforated plate is interposed between the opening 14 of the hot fuel supply pipe and the combustion block 12 to uniformly distribute the mixed fuel MF. Furthermore, the outer peripheries of the combustion block 12 and the permeable solid 22 are arranged so as to be fed into the block 12 at a rate of 1fR, and the outer peripheries of the combustion block 12 and the air permeable solid 22 are covered except for the upstream side where the mixture 1 charge flows in and the downstream side where the combustion gas is discharged. and is surrounded by a fire-resistant breaking material 20.

FIG. 4 shows a housewife showing still another embodiment of the invention according to the present application, in which in the basic configuration shown in FIG. Air permeable solids 24 having a smaller porosity than the air permeable solids constituting the block 12 are connected and arranged. The porosity of this breathable solid 24 is 90% to 95% or more (in other words, the filling rate is 10% to 5% or more).
L or less) is preferable. In this embodiment, the opening 11 portion 14 of the fuel mixture supply pipe 10 is connected to one of the permeable solids 24.
The hot fuel supplied under pressure from the supply pipe 10 is uniformly dispersed when passing through the air-permeable solid 24, so that the embodiment shown in FIGS. Thus, there is no need to separately provide the rectifying means 16. I11,
Surrounding the combustion block 12 and the permeable solids 24, 24 as shown in FIGS. This is similar to the embodiment shown in FIG.

Next, the functions and effects of the combustion engine C1 according to the present invention configured as described above will be explained below in relation to the combustion method. In the embodiment shown in FIG.
When the air-fuel mixture IIM+ is supplied through the air-fuel mixture IIM+, the flow of this air-fuel mixture is adjusted by the straightening means 16, and the mixture is uniformly dispersed and fed into the combustion block 12.The ignition means shown by reference Kano 2G When the air-fuel mixture is ignited by a heater or spark plug (for example, a heater or spark plug), a
Combustion is initiated while confined within the air-permeable solid space defined by the aperture. As mentioned earlier, air permeable solids have an extremely large practical specific surface area, and the radiation emission capacity of solids is higher than that of gases (tJ), so the high temperature combustion gas after the combustion reaction has finished. Highly effective heat exchange occurs when the gas comes into contact with an air-permeable solid, and the sensible heat l in the combustion gas is converted to 1 heat in the Okawa solid. At this time, due to the effect of solid contact, the low temperature parts of the combustion gas are suppressed, and the high temperature parts are suppressed, so the temperature becomes even as a whole and uniform combustion is obtained. (In normal flame combustion, there are locally high and low temperature areas on the flame surface.) As a result of this temperature uniformity, the generation of thermal NOx is reduced. This is because thermal NOx has a higher combustion temperature and a more intense reaction between nitrogen and oxygen, but in the device according to the present invention, there is no local temperature increase that would cause this. In addition, combustion temperature is usually used to reduce thermal NOx. When lowered, CO and UI
Unburned components such as IC are generated, but in the device of the present invention, unburned components such as CO and 01IC are generated as the unburned components come into contact with a permeable solid such as a high-temperature metal wire and are combusted. There is no risk of polluting the air.

Next, in the embodiment shown in FIG. 3, a permeable solid 2.2 is connected and arranged on the combustion gas discharge side of the combustion block 12. Therefore, high-temperature combustion gas flows into the air-permeable solid 22, where highly efficient heat exchange is performed, and the sensible heat in the combustion gas is converted into a large amount of solid radiant heat. Moreover, as explained theoretically with reference to the schematic diagram shown in FIG. The radiant heat in the combustion chamber 12 further increases, and the temperature of the combustion gas further increases and becomes even.

Further, in the embodiment shown in FIG. 4, breathable solids 2/I are connected and arranged on both sides of the combustion chamber 7 and 12, respectively. Since the combustion of the mixed fuel M F is carried out in the combustion block 12 as in the embodiment shown in FIG. It will be present in block 12. Therefore, the high temperature combustion gas generated in the book 12
When the sensible heat in the gas is converted into a large amount of solid radiant heat by flowing into each breathable solid 24, the obtained IIq4 radiant heat is
Similar to the embodiment shown in the figure, the combustion gas is injected toward the combustion block 12 on the -1- flow side.

Moreover, in the case of this embodiment, since radiant heat is emitted from both sides of the block 12, the combustion temperature in the block 12 is extremely low and even.

In any of the combustion apparatuses shown in FIGS. 2 and 3, the high temperature combustion gas with a flattened temperature distribution obtained in the combustion block 12 is sealed toward the downstream side as shown in the figure. It is used as a heat source for gas turbines, large boilers, and other industrial furnaces and heating equipment.

As described in detail below, according to the combustion method and apparatus according to the present invention, by burning the mixed fuel in a combustion block made of air-permeable solid, the temperature during combustion is reduced by the effect of solid contact. The distribution can be made uniform,
This may cause the generation of thermal NOX, CO, or
It is possible to effectively suppress the generation of unburned substances such as c. Moreover, as a characteristic of breathable solids, the combustion gas is 1% of the specific surface area.
4I) Highly efficient heat exchange occurs when it comes into contact with the large breathable solid, and the sensible heat of the combustion gas is converted into a large amount of solid radiant heat, so the combustion temperature in the combustion block is uniform. This increases the combustion efficiency and provides excellent combustion efficiency.

[Brief explanation of drawings]

Figure 1 is a schematic diagram showing the state of radiant heat of a breathable solid, Figure 2
Figure 3 is a schematic diagram of a combustion apparatus for carrying out the combustion method according to the present invention, Figure 3 is a schematic diagram of a combustion apparatus according to another invention, and Figure 4 is a diagram of a combustion apparatus according to another invention. FIG. 1 is a schematic configuration diagram of a combustion device. 10...Mixture fuel supply pipe 12=,, -° combustion block. 14... Opening 16... Rectifying means 2
0...Fire-resistant insulation material 22.24...Breathable solid 26...Ignition means patent applicant Ryo Echigo Sando Yoshizawa Aruku Otoko Do
Daido Special M Co., Ltd. Procedural Amendment (Voluntary) December 12, 1980 Director of the Japan Patent Office Kazuo Wakasugi 1, Indication of the case 1981 Patent Application No. 160456 2, Title of the invention Combustion method and device 3 , Relationship with the case of the person making the amendment Patent applicant address 1-3-17-603 Etchujima, Koto-ku, Tokyo
Name: Ryozo Echigo (2 persons) 4. Agent: 460 (1) Written amendment in the “Claims” and “Detailed Description of the Invention” columns of the specification Patent Application No. 160456/1983 , page 1, line 4 to page 2, line 15 of the specification, the claims are amended as follows. 2. Scope of Claims (1) Fuel gas and oxygen are supplied to a pan-firing block made of an air-permeable solid having a sufficiently large porosity, and in this combustion block, the fuel gas and oxygen are supplied. A combustion method characterized by burning the gas contained. (2) A combustion block made of an air-permeable solid with a sufficiently large porosity is connected to the opening side of the fuel gas supply pipe and the oxygen-containing gas supply pipe. A combustion device that does this. (3) Roku Kei Jfu 1"■Rimuro,! 1fJJJ A rectifying means is interposed between the opening of the JJJ immune supply pipe and the combustion block to uniformly distribute and distribute the star bean gas and the oxygen-containing gas. Combustion 2 device as described. (4) A combustion block made of an air permeable solid with a sufficiently large porosity is connected to the opening side of the fuel gas (b and ,') supply pipe, and the block is configured on the combustion gas discharge side of this combustion block. A combustion device characterized in that a gas permeable solid having a lower porosity than the gas permeable solid is connected and arranged. Preferably L gas and Ikjo jW-kun.”
The combustion apparatus according to claim 4, comprising a rectifying means for uniformly distributing and circulating the fuel gas (fuel gas (supply pipe and oxygen-containing gas supply pipe)). A combustion block made of an air permeable solid with a sufficiently large porosity is connected to the opening side via an air permeable solid with a small porosity, and a combustion block made of an air permeable solid with a sufficiently large porosity is connected to the combustion gas discharge side of the combustion block. A combustion device characterized by a connected arrangement of air permeable solids with low porosity.'' 2. Corrected ``air...fuel'' in lines 16 and 17 of page 6 to ``oxygen-containing gas.'' 3. Correct "mixed fuel" in line 19 of page 6 to "fuel gas and oxygen-containing gas". 4. Correct "air...fuel" in lines 1 and 2 of page 7 of same. " is corrected to "supply pipe and oxygen-containing gas." On page 7, line 13, "and air...fuel" is corrected to "supply pipe and oxygen-containing gas." 7. Next to page 17, line 20, add the following. In the embodiment, a case has been described in which hot fuel consisting of a mixture of fuel gas and air is sent to the combustion block through a common 2rL air fuel supply pipe. Separate pipes may be provided, and each supply pipe may be connected to the combustion block to mix and burn the combustion gas and air in the combustion block.Furthermore, before entering the combustion block, Alternatively, the gas mixed with the fuel gas in the block is generally air, but other gases containing oxygen may be used as appropriate." 16-

Claims (1)

[Claims] (]) Hot fuel consisting of a mixture of fuel gas and air,
A combustion method characterized in that the mixed fuel is supplied to a combustion plotter made of an air-permeable solid having a sufficiently large porosity, and the mixed fuel is combusted in this combustion block. (2) Combustion characterized in that a combustion block made of an air-permeable solid having a porosity of /I is connected to the open 1.1 side of the mixture fuel supply pipe that supplies a mixture of fuel gas and air. Device. (3) Open 1111 part of air-fuel mixture supply pipe 17i
3. The combustion apparatus according to claim 2, wherein a rectifying means is preferably interposed between the fuel mixture and the fuel mixture for uniformly distributing and circulating the fuel mixture. (4) Connect a combustion block made of air permeable solid with a sufficiently large porosity to the opening side of the mixed fuel supply pipe that supplies a mixture of fuel gas and air, and connect the combustion block to the combustion gas discharge side of this combustion block. A combustion device characterized in that air permeable solids having smaller voids '6 than the air permeable solids constituting the flocs are connected and arranged. (5) Preferably, a rectifying means is interposed between the opening of the fuel mixture supply pipe and the combustion block for uniformly distributing the fuel mixture at 11 °C. Combustion device according to scope 4. (6) Combustion with a sufficiently large air permeability (J, one body or C) through a gas permeable solid with a small air porosity on the opening side of the mixed fuel supply pipe that supplies a mixture of fuel gas and air. Connect the blocks and place this combustion gas exhaust side on the combustion gas exhaust side of the air-permeable solid, which has a smaller porosity than the air-permeable solid that makes up the block! A combustion device characterized in that 115' is arranged in series.