JP2008224144A - Waste incinerating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the exhaust of nitrogen oxide, suppress the treatment stagnation of waste and suppress wasteful consumption of combustion improver by inhibiting misfire in a combustion chamber when a waste incinerating device using a swirl type melting furnace performs low-air-ratio combustion. <P>SOLUTION: In a main combustion chamber 13 of the melting furnace for combustion melting in environment of an air ratio being 1.0 or lower, a main combustion chamber burner 61 and a pilot burner 74 are provided for supplying seed flames to the main combustion chamber 13 and for assisting the main combustion chamber burner 61, respectively. The pilot burner 74 is kept in combustion at all times during the combustion operation of waste. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for suppressing a temperature drop due to misfire of a main combustion chamber and a generation of nitrogen oxides thereby in an incinerator for gasifying and incinerating waste.

  In incinerators that process waste such as municipal and household waste, the gasification furnace decomposes the waste into pyrolysis gas and char (solids containing carbon and ash), which are solids, A melting furnace that burns pyrolysis gas and melts ash is used. In order to melt this ash by heat, a high temperature of 1200 ° C. or higher is required. However, it is not desirable from the standpoint of resource protection these days to simply increase the temperature by supplying a large amount of fuel as an auxiliary combustor and thoroughly burning it. For this reason, it has been studied to raise the temperature sufficiently without auxiliary combustion so that self-heat melting can be performed with the energy of the waste itself.

  As one of the examination subjects, in order to perform sufficient combustion in the main combustion chamber, examination for optimizing a burner that is a source of fire that causes combustion is being performed.

  For example, Patent Document 1 discloses that an ignition pilot burner provided in a main combustion chamber warms the main combustion chamber before igniting the main start burner so that the temperature is sufficiently high before the start burner is ignited. In addition, a method for preventing low temperature combustion and preventing rapid heating by a starting burner is described.

  Patent Document 2 proposes combustion in a combustion chamber provided with a main burner having a large heat capacity and an auxiliary burner having a smaller heat capacity. This is because the main burner with a large heat capacity takes time to ignite once the fire is extinguished, and not only the temperature in the combustion chamber decreases during that period, but also the energy cost for ignition. In this method, the temperature in the combustion chamber is maintained by heating with the auxiliary burner until the ignition of the combustion chamber, and using the fire of the auxiliary burner as a seed flame so that the main burner can be quickly ignited. Also described is a method of suppressing the temperature drop in the combustion chamber by continuing to ignite the auxiliary burner even after the main burner is ignited.

  On the other hand, in a high-temperature melting furnace, the higher the oxygen concentration, the more nitrogen and oxygen in the combustion air react with each other, so that nitrogen oxides called so-called thermal NOx are likely to be generated. There is. As one of them, a low air ratio combustion technique is being studied. This suppresses heat loss due to air supply, suppresses the inside of the furnace from being cooled by air supplied from the outside, and increases the temperature inside the furnace. Moreover, in order to reduce the combustion air to be used, the amount of gas that eventually becomes exhaust gas can be reduced. Furthermore, generation of thermal NOx can be suppressed by reducing the amount of air.

  Specifically, it is desirable that the air ratio in the melting furnace is 1.0 or less. This air ratio is a ratio of an actual air supply amount to a theoretical air amount capable of completely burning the pyrolysis gas and the auxiliary combustor. However, the nature of the waste to be incinerated is not constant, and the amount of pyrolysis gas and char generated in the gasification furnace varies. For this reason, when the melting furnace is actually operated, the air ratio often exceeds 1.0. In this case, since it is high-temperature combustion, the generation of thermal NOx in which nitrogen and oxygen in the air react is remarkable, and it is difficult to suppress the generation of nitrogen oxides.

  On the other hand, the method of adjusting the quantity of combustion air according to a condition is mentioned. Incineration of waste is not steady, and the situation changes from moment to moment depending on the content of the waste to be incinerated, but the oxygen concentration in the exhaust gas generated by combustion is measured, and this oxygen concentration is set to a preset value. Feedback control is performed to adjust the supply amount of combustion air so as to approach. In addition, there is also a control method for controlling the amount of air supplied based on the theoretical air amount calculated from the measured values of the amount of waste treated and the amount of auxiliary combustor used.

  Furthermore, in order to control the internal temperature while sufficiently stirring and mixing in the melting furnace, exhaust gas is circulated. This is because the amount of combustion air increases and decreases, so that stirring and mixing can be performed more reliably when exhaust gas is constantly fed than when stirring and mixing is performed. Further, since the exhaust gas itself has a lower oxygen concentration than the combustion air, it is unlikely to interfere with combustion at a low air ratio.

Japanese Patent Laid-Open No. 2002-22126 JP 2004-163070 A

  However, the combustion state in the main combustion chamber of the melting furnace may vary greatly due to fluctuations in the amount of pyrolysis gas and combustion air. In particular, when the amount of heat contained in pyrolysis gas and carbonaceous matter is high, and the amount of combustion aid used is narrowed down because the main combustion chamber is sufficiently hot, the amount of air supplied for combustion at a low air ratio If squeezed, there is a possibility that both the oxygen and the auxiliary combusting agent are extremely insufficient, and the main combustion chamber burner, which is a fire of combustion in the combustion chamber, may misfire. In addition, since the mixing of air and pyrolysis gas becomes insufficient and the ignition is delayed, the ignition of the auxiliary combustor can no longer be expected, and the combustion zone in the main combustion chamber shifts to the subsequent molten pool side. . In this case, the combustion itself in the main combustion chamber cannot be maintained.

  On the other hand, even if the combustion in the main combustion chamber stops, the molten pool melted in the main combustion chamber falls, and the molten pool in the latter stage of the melting furnace where the gas flows in maintains a high temperature. There are many. This is because the solid content in the molten state that has fallen into the melting furnace or the refractory that constitutes the melting furnace itself is still at a high temperature, so that radiant heat transfer occurs and the pyrolysis gas and auxiliary that were not burned in the main combustion chamber. This is thought to be due to the combustion of the fuel near the molten pool. However, there is a possibility that the heat load becomes excessive due to the concentration of combustion in the molten pool part, and the self-denitrification does not proceed sufficiently, and a large amount of nitrogen oxide may be discharged. .

  Therefore, the present invention suppresses misfiring in the combustion chamber, reduces the emission of nitrogen oxides, and reduces the amount of waste generated when burning at a low air ratio in a waste incinerator using a swirl melting type melting furnace. The purpose is to suppress the stagnation of processing and to suppress wasteful consumption of the auxiliary combustor.

  The present invention comprises a main combustion chamber burner for supplying a main combustion chamber seed flame to a main combustion chamber of a melting furnace that performs combustion melting in an environment controlled to an air ratio of 1.0 or less, and the main combustion chamber burner. A pilot burner that assists the above-mentioned problem is provided, and this pilot burner is always burned during the combustion operation of the waste, thereby solving the above-mentioned problems.

  Even in a low air ratio environment, by always burning the pilot burner, the combustion in the main combustion chamber can be continued without interruption, and the transition of the combustion state to the molten pool can be prevented. become. In order to realize this constant combustion, a flame detector is provided in the pilot burner, and when a misfire of the pilot burner itself is detected, the pilot burner is promptly re-ignited.

  By the incineration method according to the present invention, even in a melting furnace that performs low air ratio combustion, stoppage of combustion in the main combustion chamber can be suppressed, and waste can be processed while continuing appropriate combustion control. . As a result, generation of nitrogen oxides can be suppressed.

  Conventionally, since the pilot burner is an ignition fire type, it is considered that it is useless even if it is always burned, especially when using an LPG as an auxiliary combustor that wants to reduce the amount of combustion that takes time to save. The pilot burner was extinguished quickly. However, more than its disadvantages, by always burning the pilot burner and maintaining the combustion state, the amount of auxiliary combusting agent that is wasted due to temperature rise after misfire is reduced, and waste processing is not interrupted. The benefits of this have been greater, and the operation of the combustion system has become more efficient.

  The present invention will be described below with reference to the embodiment shown in FIG. FIG. 1 is a sectional view of a melting furnace of a waste incinerator according to the present invention. A pyrolysis gas B obtained by pyrolyzing the waste A in a gasification furnace provided upstream of the melting furnace and a solid content C containing carbonaceous matter and ash are passed through the pyrolysis gas / char inlet 63. , Supplied to the upper part of the main combustion chamber 13. On the other hand, combustion air D is supplied to the upper part of the main combustion chamber 13 from the burner combustion air port 62. These are ignited by the main combustion chamber burner 61 provided in the upper part of the main combustion chamber 13 to burn the pyrolysis gas B. The auxiliary combustion agent M used for the combustion of the main combustion chamber burner 61 itself is introduced from the auxiliary combustion agent supply pipe 64 and is also supplied with auxiliary combustion air N for burning the auxiliary combustion agent. The main combustion chambers of the pyrolysis gas / char inlet 63 and the burner combustion air inlet 62 for supplying the pyrolysis gas B and the combustion air D for burning it, which are ignited by the flame formed thereby. The supply port to 13 is installed so as to surround the periphery of the main combustion chamber burner 61.

  By the combustion, the pyrolysis gas B becomes carbon dioxide or the like, and the ash content in the solid content C is melted by high heat. The wall surface of the main combustion chamber 13 is provided with a plurality of nozzles 71, 72, 73 at equal intervals in the circumferential direction over the upper, middle, and lower stages. By blowing combustion gas and exhaust gas from these, a swirling flow is generated to stir the pyrolysis gas B and combustion air D, and the burned gas is sequentially pushed down to the molten pool 14. Further, the ash (slag) in the melted solid content C falls along the wall surface to the molten pool 14 and is discharged out of the system through the tap port 15.

  The tip of the pilot burner 74 is provided in the vicinity of the ignition portion of the main combustion chamber burner 61 facing the main combustion chamber 13. The pilot burner 74 is ignited before the main combustion chamber burner 61 in order to ignite the main combustion chamber burner 61, has a smaller heat capacity than the main combustion chamber burner 61, and is thermally decomposed. The combustion aid is burned instead of the gas B. That is, each is provided in such a positional relationship that the flame generated at the tip of the pilot burner 74 can be transferred to the main combustion chamber burner 61.

  An enlarged view of the pilot burner 74 is shown in FIG. Kerosene as fuel is supplied from the oil inlet 101 through the oil feed pipe 102 to the nozzle tip 103 at the tip of the burner. On the other hand, combustion air is supplied through the combustion air inlet pipe 105. The supplied kerosene is ignited by a spark emitted from the spark rod 108 at the tip of the spark plug 107. The diffuser 111 is a flame holder that generates a circulation flow of combustion gas in the downstream portion and promotes ignition of the air-fuel mixture.

  The pilot burner 74 is also provided with a flame detector 112 that detects the ignition state in the vicinity of the nozzle tip 103. This flame detector is not particularly limited as long as it can confirm the presence or absence of a burning flame. When it is detected that the flame has disappeared, a signal is sent to the pilot burner 74, The spark plug 107 is made to spark and quickly reignited. Specifically, an infrared type, an ultraviolet type, or the like can be cited, and it is preferable that the pilot burner 74 is attached to the rear portion to detect it.

  The amount and quality of the pyrolysis gas B supplied to the main combustion chamber 13 vary greatly depending on the waste introduced into the previous gasification furnace. If the pyrolysis gas B is particularly large, the amount of retained heat increases. Even if no auxiliary combustor is used, the combustion proceeds sufficiently. By supplying the auxiliary combustor, the combustion proceeds excessively, and the temperature may become too high. In this case, excessively high temperature is prevented by temporarily reducing the supply amount of the auxiliary combustor to the minimum. In this environment, if the combustion air in the main combustion chamber is further controlled at the low air ratio as described above, the ignition of the pyrolysis gas and carbonaceous matter also becomes unstable, synergistically with the decrease in the combustion aid, and the main combustion It is considered that misfire of the main combustion chamber 13 occurs when the chamber burner 61 is blown off.

  In the incineration method according to the present invention, when the pilot burner 74 is misfired, it is burned at all times so that it can be quickly ignited. Thereby, even if the main combustion chamber burner 61 misfires, the pilot burner 74 is still burning, so that the combustion in the main combustion chamber 13 can be maintained by the flame of the pilot burner 74. For this reason, it is possible to prevent the main combustion chamber 13 from misfiring and the combustion main body from moving to the molten pool 14 and to prevent an excessive heat load from being applied to the molten pool 14. Further, it is possible to prevent waste treatment from being delayed due to reignition and waste of the auxiliary combustion agent.

  Note that it is preferable that the main combustion chamber burner 61 and the pilot burner 74 have the same fuel because the mechanism can be simplified. Examples of the fuel include kerosene and liquefied petroleum gas (hereinafter abbreviated as “LPG”). However, since the main combustion chamber burner 61 normally consumes a large amount, the LPG that must maintain a high-pressure environment cannot easily save the labor and cost of storage. For this reason, the fuel used by the main combustion chamber burner 61 is preferably a liquid fuel at room temperature, and kerosene is preferably used. In connection with this, it is preferable that the pilot burner 74 also uses kerosene as fuel.

  The incineration method according to the present invention is meaningful for application to an environment in which the air ratio of the main combustion chamber 13 is called a so-called low air ratio and the supply amount of combustion air is suppressed. Specifically, the air ratio is preferably 1.3 or less, and if it is 1.0 or less, it is particularly easy to misfire, so the present invention is more useful. The air ratio is a ratio of an actual air amount to a theoretical air amount necessary for completely burning the pyrolysis gas B supplied to the main combustion chamber 13 and the auxiliary combustor. If air is excessive, nitrogen oxides as thermal NOx are likely to be generated in a high temperature environment where the solid content C must be meltable. Therefore, it is necessary to reduce the supply amount of combustion air D. Operate at a low air ratio of 1.0 or less. However, if the air ratio is too low, incomplete combustion occurs and carbon monoxide is likely to be generated, and a secondary combustion chamber 21 is provided downstream of the melting furnace 12 including the main combustion chamber 13 as shown in FIG. Since it becomes difficult even when trying to complete combustion, the lower limit of the control target of the air ratio in the main combustion chamber is preferably 0.8 or more, and preferably 0.9 or more. Note that the air ratio described here is a target value, and the amount and quality of the pyrolysis gas B change depending on the amount and quality of waste input, and the required amount of air may vary greatly. In particular, the above air ratio range may be deviated.

  As a specific method for controlling the air ratio as described above, for example, an oxygen concentration meter 17 is provided downstream of the main combustion chamber 13 and at the outlet 12a portion of the melting furnace 12, and the value of the oxygen concentration meter 17 is Feedback control is performed to adjust the melting furnace supply air adjustment valve 19 that adjusts the amount of combustion air D supplied to the main combustion chamber 13 by the melting furnace outlet oxygen concentration controller 18 so as to reach a predetermined target value. A method is mentioned. In place of or in combination with an oxygen concentration meter, a nitrogen oxide concentration meter and a carbon monoxide concentration meter are used to perform feedback control for adjusting the combustion conditions so as to approach the predetermined target values for each. Also good.

  The effect of the present invention is preferably exhibited when the pyrolysis gas B is sufficiently supplied, so that the temperature in the main combustion chamber 13 becomes sufficiently high, and the auxiliary combustion agent M is supplied to the main combustion chamber burner 61. When the amount of combustion air D supplied is controlled and fluctuated in order to achieve combustion at a low air ratio as described above in a situation where the amount is reduced and combustion by the main combustion chamber burner 61 is suppressed Is mentioned. Even if the synergistic effect of such a decrease in the auxiliary combustor and the shortage of the combustion air D occurs and the main combustion chamber burner 61 misfires, the pilot burner 74 that continues to burn becomes a seed fire, and the main burner quickly The combustion chamber burner 61 can be re-ignited, and the combustion state in the main combustion chamber 13 can be maintained.

  Conversely, the heat capacity supplied by the pyrolysis gas B and the components contained in the solid content C can be sufficiently secured so that combustion of the auxiliary combustor in the main combustion chamber burner 61 is unnecessary, and combustion melting is performed. If the necessary temperature can be maintained, the supply of the auxiliary combustion agent to the main combustion chamber burner 61 is intentionally stopped, the main combustion chamber burner 61 is extinguished, and only the pilot burner 74 is seeded. By continuing combustion as fire, useless consumption of the auxiliary combustor may be suppressed. The main combustion chamber burner 61 also has a role of raising the temperature at the start-up before starting incineration, and therefore often has a heat capacity sufficiently large with respect to the scale of the main combustion chamber 13. However, the burner generally used for the main combustion chamber burner 61 has a turndown ratio of about 1:10, which is a ratio of the minimum oil amount that can be supplied and the maximum oil amount (including LPG). Even if the amount of oil is reduced, sufficient energy cannot be saved. Therefore, rather than reducing the amount of oil, the combustion is stopped in the first place, and it is more effective to leave the pilot fire to the pilot burner 74 that consumes less oil than the minimum amount of oil in the main combustion chamber burner 61. Energy saving is possible.

  As a method for detecting that a sufficient heat capacity can be ensured with only the pyrolysis gas B and the solid content C, it is determined based on the temperature in the main combustion chamber 13 and the set temperature value is exceeded. A method for controlling the amount of oil is mentioned. Specifically, a thermometer for measuring the temperature in the main combustion chamber 13 is installed, and when the measured value of the thermometer reaches 1200 ° C. or more, the auxiliary combustion agent M is supplied to the main combustion chamber burner 61. And a control mechanism is provided for controlling the supply of the auxiliary combustion agent M to resume when the measured value becomes 1150 ° C. or lower.

  By maintaining the combustion state of the main combustion chamber by the method according to the present invention, generation of nitrogen oxides and carbon monoxide due to low temperature and incomplete combustion can be suppressed. In addition, since the temperature in the main combustion chamber is stabilized, combustion efficiency can be maintained, and changes due to control for making combustion conditions appropriate in the main combustion chamber or a secondary combustion chamber provided downstream thereof can be reduced. . Furthermore, it is no longer necessary to perform a warm-up operation for returning to a high temperature state, which has conventionally occurred in the event of a misfire. As a result, the consumption of the auxiliary combustor can be suppressed, and the waste processing operation is hardly interrupted. As a result, the waste processing amount can be increased.

(Example)
An embodiment in which the incineration method according to the present invention is actually executed will be described below. The structure of the main combustion chamber and its surroundings was configured as shown in FIG. 1, and the pilot burner used was the structure shown in FIG. The main combustion chamber burner 61 can be ignited by a flame burning at the tip of the pilot burner 74. The auxiliary combustion agent supplied to the main combustion chamber burner 61 and the pilot burner 74 was kerosene.

  Six 100A nozzles are provided at equal intervals in the circumferential direction as upper nozzles 71, and three 50A nozzles are provided at equal intervals in the circumferential direction as middle nozzles 72 and lower nozzles 73, respectively. In addition, these nozzles 71 to 73 are all installed in a direction inclined in the same direction so as to generate a swirling flow.

  As the flame detector 112, an infrared detector was used and provided at the rear part of the pilot burner so that a misfire at the tip of the pilot burner 74 could be detected quickly. When detected, the pilot burner 74 was directly controlled by the signal cable to spark the plug and reignite it.

The configuration and flow of the entire combustion apparatus were performed as shown in FIG. That is, in order to perform the two-stage combustion in the main combustion chamber 13 and the secondary combustion chamber 21, the combustion air D and the exhaust gas J ′ for stirring are supplied to each, and the pyrolysis gas B or its unburned gas is supplied. Burned. Further, the gas supplied to the secondary combustion chamber was cooled by supplying the exhaust gas J ′ to the outlet 12a of the melting furnace. The exhaust gas J ′ supplied from the exhaust gas recirculation blower 33 to the exhaust gas melting furnace recirculation pipe 32, the exhaust gas melting furnace outlet recirculation pipe 43, and the exhaust gas secondary combustion chamber recirculation pipe 42 is the gas J discharged from the secondary combustion chamber 21. After passing through the gas cooling chamber 25, the air preheater 26, and the temperature reducing tower 29 through a series of fluees 24, 24 'connected to the induction blower 31, the dust is collected by the bag filter 30 to remove dust. Was refluxed. In the air preheater 26, heat exchange was performed with the combustion air D before introduction sent from the melting furnace combustion air blower 27 through the air supply pipe 28. The molten ash was sent to the water tank 16 as slag F.
At this time, a thermometer 46 is provided at the outlet of the secondary combustion chamber 21, and the secondary combustion chamber combustion air regulating valve 48 is adjusted by the secondary combustion chamber outlet temperature controller 47 according to the measured value, so that the secondary combustion is performed. The amount of secondary combustion air D ′ supplied from the blower 44 to the secondary combustion chamber 21 through the secondary combustion chamber air introduction pipe 45 was adjusted. The air sent to the main combustion chamber burner 61 was adjusted by the burner supply air adjustment valve 41.

  Of the nozzles provided in the main combustion chamber, exhaust gas J ′ is supplied from the middle nozzle 72, and combustion air D is supplied from the upper nozzle 71 and the lower nozzle 73. The amount of combustion air D supplied is controlled so that the air ratio to the pyrolysis gas B is 0.8 to 1.0. For this control, an infrared laser type oxygen concentration meter 17 is provided at the melting furnace outlet 12a, and combustion air is supplied so that the value of the oxygen concentration meter becomes 1.5%. Feedback control was performed so that the air ratio was 0.8 to 0.9. Further, the amount of combustion air is controlled so that the air ratio of combustion air and pyrolysis gas B supplied to the entire combustion apparatus including the main combustion chamber 13 and the secondary combustion chamber 21 is 1.3. did.

The carbon monoxide (CO) concentration, nitrogen oxide (NOx) concentration, oxygen (O ₂ ) concentration at the location where the thermometer 46 of the exhaust gas J discharged from the secondary combustion chamber 21 is provided when operated under the above conditions. 4) The concentration and the oxygen concentration at the melting furnace outlet 12a are shown in FIG. Note that the CO concentration and the NOx concentration are converted values at a 12% oxygen concentration. The nitrogen oxide concentration averaged below 80 ppm. In addition, the carbon monoxide concentration is such that there are only two peaks at the initial time and does not appear on the graph after that. Once the combustion is stabilized, the generation of carbon monoxide is almost complete. It was found that complete combustion could be achieved while suppressing the pressure to a minimum.

  In addition, FIG. 5 shows changes in temperature in the gasification furnace 11, the melting furnace outlet 15, and the main combustion chamber 13 at this time. Although the temperature of the gasifier is affected to some extent, the main combustion chamber does not fall below 800 ° C, it can maintain an average of about 1000 ° C, and the outlet has been around 1300 ° C. In both cases, it was found that the temperature was stable, no decrease in combustion efficiency was observed, and there was no need to stop the input of waste.

(Comparative example)
In the above embodiment, when the pilot burner uses LPG as fuel and the main combustion chamber burner is ignited after ignition, the CO concentration, NOx concentration, and O ₂ concentration at the location where the thermometer 46 is provided FIG. 6 shows the oxygen concentration at the melting furnace outlet 12a. Moreover, the transition of the temperature in the gasifier, the melting furnace outlet 15, and the main combustion chamber 13 in that case is shown in FIG. Although the temperature of the gasification furnace was relatively stable, the temperature of the main combustion chamber sometimes suddenly decreased to 600 ° C. or less (shown as “temperature drop” in the figure). Immediately before the temperature drop, the carbon monoxide concentration increased rapidly, indicating that incomplete combustion had occurred, and then the temperature in the main combustion chamber dropped rapidly while nitrogen oxides were being produced in large quantities. Was. During that time, there was almost no decrease in the temperature at the taphole. This is because, even if the combustion in the main combustion chamber stops, the pyrolysis gas burns in the vicinity of the molten pool due to radiant heat transfer in the molten pool, and as a result, the temperature at the outlet is almost unchanged. It is done.

  After the temperature drop, once the supply of waste is reduced to reduce the amount of pyrolysis gas supplied, the pilot burner is ignited, the fire is transferred to the main combustion chamber burner, and the main combustion is sufficiently performed. Warm-up operation was performed until the room temperature returned (indicated by the “temperature rise” portion in the figure), and then the input of waste was resumed.

(result)
By always burning the pilot burner, it was possible to prevent the combustion in the main combustion chamber from being interrupted and to suppress the generation of carbon monoxide and nitrogen oxides due to incomplete combustion. Further, since the combustion state at a sufficient combustion temperature can be maintained for a long time, the ash can be melted without interruption, and the recovery rate of slag derived therefrom can be increased.

Sectional drawing which shows the example of the melting furnace main combustion chamber which enforces the incineration method concerning this invention (A) The figure which shows the example of the pilot burner used by this invention, (b) The figure from the fuel inlet side of (a) Flow chart showing an example of an incineration apparatus and method for carrying out the present invention Graph showing _CO, and changes of the concentration of O 2, NOx in the embodiment The graph which shows the transition of the temperature of the gasification furnace in the Example, the melting furnace Graph showing changes in concentration of CO, O ₂ and NOx in Comparative Example Graph showing changes in gasification furnace and melting furnace temperatures in comparative examples

Explanation of symbols

A Waste B Pyrolysis gas C Solids D, D 'Combustion air E Gas after combustion F Slag J, J' Exhaust gas M Combustion agent N Combustion combustion air 11 Gasification furnace 12 Melting furnace 12a (of melting furnace ) Outlet 13 Main combustion chamber 14 Molten pool 15 Outlet 16 Water tank 17 Oxygen concentration meter 18 Melting furnace outlet oxygen concentration controller 19 Melting furnace supply air adjustment valve 20, 20 'Signal cable 21 Secondary combustion chambers 24, 24' Smoke Road 25 Gas cooling chamber 26 Air preheater 27 Air blower for melting furnace combustion 28 Air supply pipe 29 Temperature reducing tower 30 Bag filter 31 Induction fan 32 Exhaust gas melting furnace recirculation pipe 33 Exhaust gas recirculation fan 41 Burner supply air adjustment valve 42 Exhaust gas Secondary combustion chamber circulation pipe 43 Exhaust gas melting furnace outlet circulation pipe 44 Secondary combustion blower 45 Secondary combustion chamber air introduction pipe 46 Thermometer 47 Secondary combustion chamber outlet temperature controller 48 Secondary combustion Combustion air regulating valve 61 Main combustion chamber burner 62 Burner combustion air port 63 Pyrolysis gas / char introduction port 64 Auxiliary combustion agent supply pipe 71 Upper nozzle 72 Middle nozzle 73 Lower nozzle 74 Pilot burner 101 Oil inlet 102 Oil feed pipe 103 Nozzle tip 105 Combustion air inlet pipe 107 Spark plug 108 Spark rod 111 Diffuser 112 Flame detector

Claims (4)

A waste incineration method in which a pyrolysis gas obtained by thermally decomposing waste and a solid content are burned and melted in a main combustion chamber controlled in an environment having an air ratio of 0.8 to 1.0,
Incineration of waste, characterized in that, during the combustion and melting, a pilot burner for igniting a burner for a main combustion chamber that supplies a seed flame for the main combustion chamber and burning with a combustion aid is always burned. Method.   The waste incineration method according to claim 1, wherein a misfire of the pilot burner is detected by a flame detector, and the pilot burner is re-ignited promptly after the detection to cause constant combustion.   The waste incineration method according to claim 1 or 2, wherein kerosene is used as fuel for the main combustion chamber burner and the pilot burner.   When the temperature required for the combustion melting can be maintained only by the heat capacity of the pyrolysis gas and the carbonaceous matter contained in the solid content, the supply of the auxiliary combustor to the main combustion chamber burner is stopped. 4. The waste incineration method according to claim 1, wherein the main combustion chamber burner is extinguished and only the pilot burner is ignited.

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