JPS6012522B2 - combustion device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a combustion device, and particularly to a combustion device capable of reducing nitrogen oxides in combustion exhaust gas.

In combustion furnaces such as boilers used in various factories and industries, there is a strong social need to suppress the amount of nitrogen oxides (hereinafter referred to as NOx) contained in the combustion exhaust gas to the lowest possible value. It is requested. This is in response to social demands to prevent environmental pollution, and although this demand is expected to become even stricter in the future, the current regulation value for N○x is that the nitrogen (N) content in fuel is 0.
．． 2%, 5 supine positions are prescribed. Combustion methods conventionally used in boilers include the two-stage combustion method and the recirculation gas injection method, and with these combustion methods, it is common for the N○x value to be 100 to 15. However, it is strongly desired to reduce this value from 1/2 to 1/Chikuri degree. FIG. 1 and FIG. 2 are explanatory diagrams of a boiler having a structure according to the prior art.

1 and 2, the combustion air of the boiler is sent by an air blower 1 and enters an air conduit or air duct 2, where a part of the combustion exhaust gas is introduced from a mixing device 4 by a recirculation fan 3. mixed. Furthermore, the mixed gas is appropriately distributed and sent to the wind box 5 for the load burner and the wind box 6 for the three-stage hot rice bran. This is done by the mixing register 8.The fuel and air sent into the furnace 9 are combusted, and harmful gases such as N○x are discharged as combustion exhaust gas.The partition plate 10 and the distribution damper 11 are It is provided to redistribute the gas introduced and mixed from the device 4 and send it to the load burner wind box 5 and the two-J stage combustion wind box 6.A conventional boiler configured in this way As a measure to reduce NOx in the combustion exhaust gas, air from the two-stage combustion air register 8 is supplemented to compensate for the lack of air from the load burner air register 7, and the amount of air in the furnace 9 is increased. It is considered that the amount of N○x generated can be reduced by slowing down the combustion reaction of the gas and lowering the flame temperature.

According to the conventional boiler structure, for example, there is a sufficient height from the lowest burner to the two-stage combustion air register 8, so the combustion coming out of the burner is in an air-starved state.
In addition, since the fuel is exposed to high temperatures, the fuel is carbonized by thermal decomposition, polymerization, etc. Once carbonized, the fuel has a slower combustion speed and a longer combustion time than fuel that is not carbonized, so it cannot be completely burned in the furnace 9, reaches a low temperature, and is carried over. In this state, the amount of dust in the exhaust gas increases, and the amount of enzyme does not decrease, so N○x cannot be reduced sufficiently, or the exit of the furnace 9, especially from the burner section of the furnace 9, There was an economical problem as it required a longer distance from the fuel to the fuel.If we focus on fuel that is not carbonized, the primary combustion results in a high temperature, and after a certain period of time, the secondary combustion occurs in a state where there is an excess of air. The present invention solves the drawbacks of the above-mentioned prior art and has the effect of An object of the present invention is to provide a combustion device that can suppress an increase in unburned components while reducing N○x.

A first configuration of the present invention to achieve this object includes a primary combustion chamber that performs primary combustion in an oxygen atmosphere with an amount of enzyme smaller than the amount of enzyme required for combustion of fuel; A furnace is constituted by a secondary combustion chamber that performs secondary combustion of the unburned content generated in the primary combustion chamber, and enzyme-containing gas for 2J stage combustion is sent to the passage between the secondary combustion chamber and the primary combustion chamber. A first two-stage combustion air introduction means is provided to supply an enzyme-containing gas to the downstream side of the combustion gas of the secondary combustion chamber to combust the unburned content generated in the secondary combustion chamber. A second J-stage combustion air introduction means is provided in the secondary combustion chamber, and the second J-stage combustion air introduction means and the first J-stage combustion air introduction means are provided in a common wind box. The second J-stage combustion air introduction means is characterized in that an air register is provided for adjusting the supply amount of the oxygen-containing gas. Further, the second configuration of the present invention includes a primary combustion chamber in which hawk combustion is performed in an oxygen atmosphere with an amount of enzyme smaller than the amount of enzyme required for combustion of the fuel, and a flow connected to the primary combustion chamber through a condenser section. A furnace is constituted by a secondary combustion chamber that performs secondary combustion of unburned content generated in the primary combustion chamber, and air is introduced for co-stage combustion to supply oxygen-containing gas for co-stage combustion to the condenser section. It is characterized by having a means.

EMBODIMENT OF THE INVENTION Hereinafter, one embodiment of the combustion apparatus of the present invention will be described with reference to the accompanying drawings.

3 and 4 a, b are structural explanatory diagrams of a boiler according to an embodiment of the present invention, FIG. 3 is an explanatory diagram of the main parts, and FIG. 4 a, b
is an enlarged explanatory view of the combustion mechanism section A, that is, the main part of the load burner wind box. In each of the above figures, the primary combustion chamber 21 and the secondary combustion chamber 22 constitute a furnace (main combustion chamber). In this embodiment, the primary combustion chamber 21 is constituted by a plurality of compact cyclone furnaces that perform Takazusa combustion. Further, as shown in the figure, a condenser section is formed in the furnace passage section between the primary combustion chamber 21 and the secondary combustion chamber 22, and an inlet 23 for the second-stage combustion air is provided in the constriction section. Furthermore, an air register 24 for =J stage combustion is attached to the two stage combustion chamber 22.
Note that the air for second-stage combustion is supplied to the air inlet 23 for the J-stage combustion and the air register 24 for the J-stage combustion by a common wind box 31 for the second J-stage combustion. Combustion air containing oxygen in an amount smaller than the amount of enzyme required for combustion of fuel is introduced into the primary combustion chamber 21 from the load burner wind box 25. A swirling motion is applied by the air register 26 so that the air is introduced into the primary combustion chamber 21.

A plurality of load burners 27 are arranged near the load burner air register 26. An ignition torch 28 is used to ignite the load burner 27, and it can be easily ignited. The combustion air is sent from the air blower through the air duct 29, mixed with a portion of the combustion exhaust gas sent from the gas recirculation fan, and then passed through the load burner air register 26 and the two-stage combustion air inlet 23. sent. As explained above, the boiler according to this embodiment has a structure in which one combustion is performed in two stages by separating the primary combustion chamber 21, which serves as a precombustion chamber, and the secondary combustion chamber 22, which performs main combustion. That is.

In this embodiment, since the primary combustion chamber 21 is constituted by a compact cyclone furnace, combustion gas,
The air intake is forced and effective, and combustion is promoted even if the air volume is low enough. Furthermore, in this embodiment, the introduction ports 23 for the two-stage combustion air are provided in the striped flow section, and are also provided immediately after each load burner 27, so that intermittent combustion is less likely to occur. Since the air for second-stage combustion is rapidly mixed and provided by the condenser section, the time under high temperature and low oxygen conditions is short, making it difficult for the fuel to be carbonized. Therefore, even if measures against NQ in combustion exhaust gas such as pollutants are strengthened, the amount of dust in the exhaust gas does not increase. Furthermore, it has become possible to significantly suppress the generation of toxic gases such as CO gas. Fig. 5 and Fig. 6 are explanatory diagrams to more clearly explain the combustion effect of the combustion device according to this embodiment, and Fig. 5 is an explanatory diagram of the combustion situation in the conventional poiler shown for comparison. , FIG. 6 is an explanatory diagram of the combustion situation in the boiler according to this embodiment.

In the figure, F indicates flame. In the case of boilers using conventional technology, the flame is large and indicates incomplete combustion, whereas in the case of combustion in the boiler of this example, the flame is small, indicating that combustion is carried out effectively. . On the other hand, from an economic point of view, the combustion diamond layer according to this embodiment does not require particularly complicated and expensive parts in its structure, and is extremely advantageous in terms of manufacturing cost.

The effects of the combustion device having the first configuration of the present invention are as follows. As is well known, there are two types of NOx: thermal NOx and fuel NOX. Thermal N○x is generated by the activation of N2 in the air, so
It can be reduced by lowering the flame temperature. However, since fuel N○x is generated by atomic N in the fuel, it is generated when the fuel is combusted regardless of the flame temperature. Therefore, the only way to reduce the fuel NQ is to reduce the generated N*x using a reducing agent. It is economically desirable to generate this reducing agent from the N content in the fuel. However, delicate 02 partial pressure control is required to generate a reducing agent from the N component in the fuel and reduce N○x. That is, since the existence time of the reducing agent is extremely short, it is necessary to appropriate the method of providing 02 and the reduction reaction time. Furthermore, it is desired that the combustion device ultimately not emit any fuel.
Conventionally, it has been impossible to satisfy all of these conditions. However, according to the combustion device having the first configuration of the present invention, it has become possible to satisfy all of these conditions. That is, first, the air distribution between primary air and secondary air is controlled to determine the total stage combustion rate, and then the service
Suppress the occurrence of Maru N○x.

Next, by supplying 02 to the lotus passages of the primary combustion chamber and the secondary combustion chamber by the first two-stage combustion air introduction means, the life of the fuel N○x is shortened and the reaction of the reducing agent is accelerated. have it done. Moreover, since the first = J-stage combustion air introduction means and the second two-stage combustion air introduction means are provided in a common wind box, it is possible to simultaneously satisfy the above-mentioned reduction reaction and complete combustion. 02 can be appropriately controlled. In particular, when multiple primary combustion chambers are provided,
It is possible to simultaneously achieve a reduction in thermal N○x through two-stage combustion and a reduction reaction using a reducing agent for N○x, which has a very different reaction rate. Further, the effects of the combustion apparatus having the second configuration of the present invention are as follows.

In other words, since clear azusa combustion is performed in the primary combustion chamber,
Combustion gas and air are forcibly mixed to achieve combustion with a small amount of air, and even if the amount of air is sufficiently low, combustion is promoted.
Furthermore, since a condenser section is provided in the furnace communication section between the primary combustion chamber and the secondary combustion chamber, the gas is rapidly mixed in the condenser section to prevent carbonization of the fuel, and to prevent carbonization of the fuel. By making 02 exist uniformly, N○x can be effectively reduced. As described above, the effects of the present invention are remarkable.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of a boiler according to the prior art, Fig. 2 is an explanatory diagram of the combustion mechanism section which is the main part thereof, Fig. 4 is an explanatory diagram of the combustion mechanism that is the main part, Fig. 5 is an explanatory diagram of the combustion situation in a boiler that is a conventional technology, and Fig. 6 is an explanatory diagram of the combustion situation in a boiler that is an embodiment of the present invention. It is a diagram. 1... Air blower, 2, 29... Air duct, 3... Gas recirculation fan, 4... Mixing device, 5, 25...
Wind box for load burner ~ 6,31... Wind box for two-stage combustion, 7, 26...air register for load burner, 8, 24...= air register for first-stage combustion, 9... Furnace 10, 30...
・Partition plate, 11... Distribution damper, 21... Primary combustion chamber, 22... Secondary combustion chamber, 23... Air inlet for 21st stage combustion ~ 27. Skin ...Load burner, 2
8...Ignition torch. Ice i figure Ice 2 figure Age 3 figure Ice 4 figure Age 5 figure Age 6 figure

Claims (1)

[Scope of Claims] 1. A primary combustion chamber that performs primary combustion in an enzyme atmosphere with an amount of enzyme smaller than that required for combustion of fuel, and a primary combustion chamber that communicates with the primary combustion chamber and removes unburned matter generated in the primary combustion chamber. A first two-stage combustion air introduction which constitutes a furnace with a secondary combustion chamber for performing secondary combustion, and supplies an enzyme-containing gas for two-stage combustion to a communication portion between the secondary combustion chamber and the primary combustion chamber. a second two-stage combustion air introducing means for supplying an enzyme-containing gas for burning unburned matter generated in the secondary combustion chamber to the downstream side of the combustion gas of the secondary combustion chamber; provided in the combustion chamber, the second two-stage combustion air introduction means and the first two-stage combustion air introduction means have a common window box, and the second two-stage combustion air introduction means has a common window box. A combustion device characterized by being provided with an air register that adjusts the amount of oxygen-containing gas supplied. 2. A primary combustion chamber that performs stirring combustion in an enzyme atmosphere with an amount of enzyme less than that required for combustion of fuel, and unburned matter that is in communication with the primary combustion chamber via a condenser section and that is generated in the primary combustion chamber. A combustion apparatus comprising a furnace comprising a secondary combustion chamber for secondary combustion, and a second-stage combustion air introducing means for supplying enzyme-containing gas for second-stage combustion to the condenser section.