JP2016194376A - Waste incinerator and waste incineration method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a waste incinerator and a method that prevent imperfect combustion in a secondary combustion chamber of a waste incinerator.SOLUTION: A secondary combustion chamber 12 provided successively to a combustion chamber 11 of an incinerator for incinerating waste has an exhaust gas intake 13 through which an exhaust gas from the combustion chamber 11 flows in the secondary combustion chamber 12 on a low side face, an exhaust gas outlet 19 for discharging a waste gas after secondary combustion on an upper part, and a gas blow-in opening 20 for secondary combustion at an intermediate position between the exhaust gas intake 13 and the exhaust gas outlet 19 in a height direction, respectively. The exhaust gas intake 13 is so provided that the exhaust gas generates an exhaust swirl flow in one direction on a horizontal plane in the secondary combustion chamber at a position radially shifting from a center axis of the secondary chamber 12, a spiral guide vane 17 for guiding and allowing the exhaust gas swirl flow to flow upward is provided in the secondary combustion chamber 12, and the gas blow-in opening 20 for secondary combustion is so provided as to blow the gas for secondary combustion into the secondary combustion chamber from outside in the same direction with the exhaust gas swirl flow.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a waste incinerator and a waste incineration method.

  A waste incinerator that incinerates waste in a combustion chamber is often connected to a secondary combustion chamber that burns the exhaust gas in order to receive the exhaust gas from the combustion chamber and recover its thermal energy. Exhaust gas discharged from the combustion chamber contains combustible gas. The combustible gas is combusted in the secondary combustion chamber to increase the temperature, and the high-temperature exhaust gas discharged from the secondary combustion chamber is heat-exchanged with a boiler or the like. In this way, heat energy is recovered. A secondary combustion gas containing air is blown into the secondary combustion chamber, and the combustible gas contained in the exhaust gas is burned well.

  In order to promote the mixing of the combustible gas in the secondary combustion chamber and the secondary combustion air as the secondary combustion gas, it is discarded that the secondary combustion air is blown so as to generate a swirl flow in the secondary combustion chamber. Patent Document 1 proposes a secondary combustion chamber for a melting furnace for gasifying and melting an object.

  In this Patent Document 1, the secondary combustion chamber 10 has an exhaust gas inlet for flowing exhaust gas from the melting furnace into the secondary combustion chamber on the lower side surface, and an exhaust gas exhaust port for discharging exhaust gas after secondary combustion on the upper side. A secondary combustion air inlet is provided at an intermediate height between the exhaust gas inlet and the exhaust gas outlet, and the exhaust gas inlet is exhausted in one direction in a horizontal plane in the secondary combustion chamber due to the inflow of exhaust gas. The secondary combustion air inlet has a plurality of nozzles that generate a reverse swirl air flow in a direction opposite to the exhaust gas swirl flow in the horizontal plane by blowing the secondary combustion air. That is, both the exhaust gas inlet and the secondary combustion air injection port have the center of the flow distribution of the inflowing exhaust gas at the radial position where the inflowing exhaust gas and the injected secondary combustion air are respectively deviated from the vertical center line of the furnace body. A swirling flow is generated by setting the flow rate so as to be positioned. The secondary combustion air blowing port deviates the center of the flow rate distribution from the vertical center line as described above by setting the flow rates of the blown secondary combustion air from the plurality of nozzles to be different.

JP2014-016053

  Although the secondary combustion chamber disclosed in Patent Document 1 can also be applied to the secondary combustion chamber in a waste incinerator, the combustion behavior in the incinerator fluctuated due to variation in the type and amount of waste. In this case, since the flow rate and flow velocity of the inflowing exhaust gas flowing into the secondary combustion chamber fluctuate, the flow velocity of the swirling inflowing exhaust gas formed from the biased inflowing exhaust gas inlet, the direction of the swirling flow (the flow pattern of the swirling flow) ) Will fluctuate.

  If the flow rate of the inflowing exhaust gas and the direction of the swirl flow fluctuate, there will be a problem that the same direction swirl flow formation by blowing in the secondary combustion gas and the stirring and mixing action by the reverse swirl flow formation will not be performed sufficiently, and combustible There may be a problem that incomplete combustion of the gas occurs and the CO concentration in the exhaust gas increases.

  In view of such circumstances, the present invention reliably ensures combustible gas and secondary combustion gas in the secondary combustion chamber even if the combustion behavior of the incinerator fluctuates due to variations in the type of waste and the amount of treatment. It is an object of the present invention to provide a waste incinerator and a waste incineration method which are mixed to prevent incomplete combustion.

  According to the present invention, the above-mentioned problems are solved by the following first and second inventions for the waste incinerator and by the third and fourth inventions for the waste incineration method, respectively.

[Waste incinerator]
<First invention>
A combustion chamber of an incinerator that incinerates waste, and a secondary combustion chamber that receives and combusts an exhaust gas containing a combustible gas from the combustion chamber, and the secondary combustion chamber receives the exhaust gas from the combustion chamber. The exhaust gas inlet that flows into the next combustion chamber is on the lower side, the exhaust gas outlet that discharges the exhaust gas after secondary combustion is on the upper side, and the secondary combustion gas inlet is in the height direction between the exhaust gas inlet and the exhaust gas outlet. In the middle of the waste incinerator,
The exhaust gas inlet is provided at a position radially deviated with respect to the central axis of the secondary combustion chamber so that the exhaust gas generates a one-way exhaust gas swirl flow in a horizontal plane in the secondary combustion chamber,
A spiral guide vane is provided in the secondary combustion chamber to guide the exhaust gas swirl flow upward.
A waste incinerator characterized in that a secondary combustion gas injection port is provided so as to inject secondary combustion gas into the secondary combustion chamber from the outside in the same direction as the exhaust gas swirl flow.

<Second invention>
A combustion chamber of an incinerator that incinerates waste, and a secondary combustion chamber that receives and combusts an exhaust gas containing a combustible gas from the combustion chamber, and the secondary combustion chamber receives the exhaust gas from the combustion chamber. The exhaust gas inlet that flows into the next combustion chamber is on the lower side, the exhaust gas outlet that discharges the exhaust gas after secondary combustion is on the upper side, and the secondary combustion gas inlet is in the height direction between the exhaust gas inlet and the exhaust gas outlet. In the middle of the waste incinerator,
The exhaust gas inlet is provided at a position radially deviated with respect to the central axis of the secondary combustion chamber so that the exhaust gas generates a one-way exhaust gas swirl flow in a horizontal plane in the secondary combustion chamber,
A spiral guide vane is provided in the secondary combustion chamber to guide the exhaust gas swirl flow upward.
A waste incinerator characterized in that a secondary combustion gas blow-in port is provided so as to blow a secondary combustion gas into the secondary combustion chamber from the outside in a direction opposite to the exhaust gas swirl flow.

  In the first and second aspects of the invention, the secondary combustion gas inlet receives a part of the exhaust gas after dust removal discharged from the secondary combustion chamber together with air as recirculated exhaust gas, and mixes the secondary combustion gas. The secondary combustion gas can be generated and blown into the secondary combustion chamber.

[Waste incineration method]
<Third invention>
A combustion chamber of an incinerator that incinerates waste, and a secondary combustion chamber that receives and combusts an exhaust gas containing a combustible gas from the combustion chamber, and the secondary combustion chamber receives the exhaust gas from the combustion chamber. The exhaust gas inlet that flows into the next combustion chamber is on the lower side, the exhaust gas outlet that discharges the exhaust gas after secondary combustion is on the upper side, and the secondary combustion gas inlet is in the height direction between the exhaust gas inlet and the exhaust gas outlet. In the waste incineration method by the waste incinerator that each has in the middle position between,
Exhaust gas flows into the secondary combustion chamber from an exhaust gas inlet provided at a position radially deviated from the central axis of the secondary combustion chamber, and a one-way exhaust gas swirl flow is generated in the horizontal plane in the secondary combustion chamber. Give rise to
With the spiral guide vane provided in the secondary combustion chamber, the exhaust gas swirl flow is guided upward,
Waste from a waste incinerator provided to blow secondary combustion gas from the outside into the secondary combustion chamber in the same direction as the exhaust gas swirl flow from the secondary combustion gas blowing port Incineration method.

<Fourth Invention>
A combustion chamber of an incinerator that incinerates waste, and a secondary combustion chamber that receives and combusts an exhaust gas containing a combustible gas from the combustion chamber, and the secondary combustion chamber receives the exhaust gas from the combustion chamber. The exhaust gas inlet that flows into the next combustion chamber is on the lower side, the exhaust gas outlet that exhausts the exhaust gas after secondary combustion is on the upper side, and the gas inlet for secondary combustion is in the height direction. In the waste incineration method by the waste incinerator that each has in the middle position between,
Exhaust gas flows into the secondary combustion chamber from an exhaust gas inlet provided at a position radially deviated from the central axis of the secondary combustion chamber, and a one-way exhaust gas swirl flow is generated in the horizontal plane in the secondary combustion chamber. Give rise to
With the spiral guide vane provided in the secondary combustion chamber, the exhaust gas swirl flow is guided upward,
Waste from a waste incinerator provided to inject secondary combustion gas from the outside into the secondary combustion chamber in the direction opposite to the exhaust gas swirl flow from the secondary combustion gas inlet Incineration method.

  In the third and fourth inventions, a part of the exhaust gas after dust removal discharged from the secondary combustion chamber is received as a recirculated exhaust gas and mixed with air to generate a secondary combustion gas, and the secondary combustion gas Can be blown into the secondary combustion chamber from the secondary combustion gas inlet.

  In the first to fourth inventions, an exhaust gas swirling flow is generated in the lower part of the secondary combustion chamber due to the inflow exhaust gas from the exhaust gas inlet at the lower part of the secondary combustion chamber, and this is swirling along the spiral guide vane. Ascending, the secondary combustion gas is blown in the rising process. In the first and third inventions, the blowing direction of the secondary combustion gas is the same direction as the exhaust gas swirl flow, and the swirl flow is strengthened to sufficiently mix the secondary combustion gas. In the fourth invention, the blowing direction of the secondary combustion gas is opposite to the exhaust gas swirl flow, the residence time of the exhaust gas swirl flow in the secondary combustion chamber is increased, and mixing of the secondary combustion gas is performed. Well done. Thus, incomplete combustion of the combustible gas in the exhaust gas is prevented.

  As described above, the present invention is guided by the spiral guide vane in the process in which the exhaust gas swirl formed by the exhaust gas flowing into the secondary combustion chamber from the exhaust gas inlet at the lower part of the secondary combustion chamber rises toward the exhaust gas outlet. By doing so, the swirl flow path of the exhaust gas is formed uniformly, so even if the combustion behavior in the combustion furnace fluctuates and the inflow exhaust gas flow rate and the inflow exhaust gas flow rate fluctuate, there is no change in the flow path of the inflow exhaust gas, An inflowing exhaust gas swirling flow can be reliably generated by injecting secondary combustion gas, and the inflowing exhaust gas and the secondary combustion gas are sufficiently and reliably agitated and mixed even in the event of fluctuations in combustion behavior. The gas is burned sufficiently. At that time, since the secondary combustion gas is blown in from the secondary combustion gas blow-in port in the same direction as the swirling direction of the exhaust gas or in the opposite direction, further effects are produced. First, when the secondary combustion gas is blown in the same direction as the swirling direction of the inflowing exhaust gas, the swirling flow of the exhaust gas in the secondary combustion chamber is strengthened, and the inflowing exhaust gas and the secondary combustion gas are sufficiently mixed. As a result of combusting the combustible gas sufficiently, the combustible gas is completely combusted and the amount of CO in the exhaust gas can be suppressed. Next, when the secondary combustion gas is blown in the direction opposite to the swirling direction of the inflowing exhaust gas, the secondary combustion gas is opposed to the inflowing gas swirling flow, and the flow of the swirling inflowing exhaust gas flow is disturbed. As a result, the flow velocity decreases, the residence time in the secondary combustion chamber increases, the combustible gas can be burned more reliably, and the CO concentration in the exhaust gas can be reliably suppressed. Since there is an effect of increasing the gas residence time in the secondary combustion chamber, the secondary combustion chamber can be made smaller than before and the cost can be reduced when the residence time is made equal to that of the conventional secondary combustion chamber.

It is a cross-sectional view which shows the schematic shape of the combustion chamber of the waste incinerator in one Embodiment of this invention, and the secondary combustion chamber connected with this. It is an expansion cross-sectional view of the secondary combustion chamber in FIG. 1, (A) shows one form, (B) shows another form. FIG. 2 is an enlarged longitudinal sectional view of a secondary combustion chamber in FIG. 1.

  Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a cross-sectional view showing a schematic shape of a combustion chamber of a waste incinerator and a secondary combustion chamber connected thereto in the present embodiment.

  In FIG. 1, a substantially cylindrical secondary combustion chamber 12 having an axis in the vertical direction is provided in communication with a portion of the combustion chamber 11. 2 (A) and FIG. 3 are a cross-sectional view and a vertical cross-sectional view, respectively, in which only the secondary combustion chamber 12 is enlarged, and FIG. 2 (B) is a modification of FIG. 2 (A).

  As shown in FIGS. 1 and 2A, the secondary combustion chamber 12 has a portion in the circumferential direction of the substantially cylindrical secondary combustion chamber 12 at the downstream end of the side wall 11A of the combustion chamber 11 (see FIG. 1). And the lower end portion of the secondary combustion chamber 12 is provided so as to communicate with the combustion chamber 11 as shown in FIG. This communicating portion forms an exhaust gas inlet 13 through which combustible gas-containing exhaust gas flows from the combustion chamber 11 into the secondary combustion chamber 12. A tangential wall 14 located on the tangent line of the secondary combustion chamber 12 extends from the exhaust gas inlet 13 and is connected to a substantially cylindrical cylindrical wall 15. Accordingly, the exhaust gas flowing into the secondary combustion chamber 12 from the exhaust gas inlet 13 flows in a tangential direction toward the cylindrical wall 15 along the tangential wall 14 located in a radial direction with respect to the axis, As a result, a swirl flow is formed counterclockwise in the example of FIG.

  A spiral guide vane 17 forming a spiral plate is attached to a shaft body 16 positioned on the axis in the secondary combustion chamber 12 having a substantially cylindrical shape. In the present embodiment, the spiral guide vane 17 is provided from the lower end to the upper end of the secondary combustion chamber 12 and extends upward while being wound around the shaft body 16 in the counterclockwise direction.

  An exhaust gas discharge port 19 is formed in the upper end wall of the secondary combustion chamber 12. The exhaust gas discharge port 19 is connected to various devices (not shown) for detoxifying the exhaust gas discharged via a pipe line.

  The cylindrical wall 15 of the secondary combustion chamber 12 is provided with a secondary combustion gas inlet 20 for blowing secondary combustion gas into the secondary combustion chamber 12 at a plurality of positions in the circumferential direction at an intermediate position in the vertical direction. Yes. The secondary combustion gas inlet 20 is formed by a nozzle or a slit. As shown in FIG. 2A, the secondary combustion gas inlet 20 has a substantially cylindrical secondary combustion so that the secondary combustion gas flows in the same direction as the swirling flow of the inflowing exhaust gas. It is blown into the cylinder wall 15 of the chamber with a tangential component. The secondary combustion gas is blown from the secondary combustion gas inlet 20 as a mixed gas formed by, for example, secondary combustion air and part of the exhaust gas after detoxification.

  The secondary combustion gas inlets 20 provided at a plurality of positions in the circumferential direction of the cylindrical wall 15 of the secondary combustion chamber 12 are preferably disposed along the spiral direction of the spiral guide vane 17, and more preferably. In the vertical direction, they are arranged at intermediate positions between the pitch intervals of the spiral guide vanes.

  In the apparatus of this embodiment, when the exhaust gas containing the combustible gas generated in the combustion chamber 11 flows into the secondary combustion chamber 12 from the exhaust gas inlet 13, a counterclockwise swirling flow is generated in the lower portion of the secondary combustion chamber 12. Is produced. The swirling flow is guided by the spiral guide vane 17 and rises while swirling in a state where the swirling flow path is constant. Since the secondary combustion gas is blown from the secondary combustion gas inlet 20 so as to form a flow in the same direction as the swirl flow, the swirl flow of the exhaust gas is increased by the secondary combustion gas in the process of rising. The turning is strengthened.

  Even if the combustion behavior in the combustion furnace fluctuates and the inflow exhaust gas flow rate and the inflow exhaust gas flow velocity fluctuate, the swirling path of the swirling exhaust gas is not changed by the spiral guide vane, and the secondary combustion gas Since the inflowing exhaust gas swirl flow can be reliably generated by blowing, the combustible gas is sufficiently burned in a state where the inflowing exhaust gas and the secondary combustion gas are sufficiently and reliably agitated and mixed. Is completely burned and the amount of CO in the exhaust gas can be suppressed.

  In the present invention, the secondary combustion gas can be blown in the direction opposite to that shown in FIG. 2A in the direction shown in FIG. That is, the secondary combustion gas is blown from the secondary combustion gas inlet 20 so as to face the clockwise direction with respect to the exhaust gas flow rising while making a counterclockwise swirl flow by the spiral guide vane 17. In this case, since the secondary combustion gas is blown in the direction opposite to the swirling direction of the inflowing exhaust gas, the secondary combustion gas faces the inflowing gas swirling flow, and the flow of the swirling inflowing exhaust gas flow is disturbed. As a result, the flow velocity is reduced, the residence time in the secondary combustion chamber 12 is increased, the combustible gas can be burned more reliably, and the CO concentration in the exhaust gas can be reliably suppressed. Since there is an effect of increasing the gas residence time in the secondary combustion chamber 12, when the residence time is made equal to that of the conventional secondary combustion chamber 12, the secondary combustion chamber 12 can be made smaller than before and the cost can be reduced. it can.

  In the present invention, the spiral guide vane 17 is not limited to the illustrated example, and may be supported on the peripheral wall of the secondary combustion chamber 12 without the shaft body 16 without being attached to the shaft body 16.

DESCRIPTION OF SYMBOLS 11 Combustion chamber 12 Secondary combustion chamber 13 Exhaust gas inlet 17 Spiral guide vane 19 Exhaust gas outlet 20 Secondary combustion gas inlet

Claims (6)

A combustion chamber of an incinerator that incinerates waste, and a secondary combustion chamber that receives and combusts an exhaust gas containing a combustible gas from the combustion chamber, and the secondary combustion chamber receives the exhaust gas from the combustion chamber. The exhaust gas inlet that flows into the next combustion chamber is on the lower side, the exhaust gas outlet that exhausts the exhaust gas after secondary combustion is on the upper side, and the gas inlet for secondary combustion is in the height direction. In the middle of the waste incinerator,
The exhaust gas inlet is provided at a position radially deviated with respect to the central axis of the secondary combustion chamber so that the exhaust gas generates a one-way exhaust gas swirl flow in a horizontal plane in the secondary combustion chamber,
A spiral guide vane is provided in the secondary combustion chamber to guide the exhaust gas swirl flow upward.
A waste incinerator characterized in that a secondary combustion gas injection port is provided so as to inject secondary combustion gas from the outside into the secondary combustion chamber in the same direction as the exhaust gas swirl flow. A combustion chamber of an incinerator that incinerates waste, and a secondary combustion chamber that receives and combusts an exhaust gas containing a combustible gas from the combustion chamber, and the secondary combustion chamber receives the exhaust gas from the combustion chamber. The exhaust gas inlet that flows into the next combustion chamber is on the lower side, the exhaust gas outlet that exhausts the exhaust gas after secondary combustion is on the upper side, and the gas inlet for secondary combustion is in the height direction. In the middle of the waste incinerator,
The exhaust gas inlet is provided at a position radially deviated with respect to the central axis of the secondary combustion chamber so that the exhaust gas generates a one-way exhaust gas swirl flow in a horizontal plane in the secondary combustion chamber,
A spiral guide vane is provided in the secondary combustion chamber to guide the exhaust gas swirl flow upward.
A waste incinerator characterized in that a secondary combustion gas injection port is provided so as to inject secondary combustion gas into the secondary combustion chamber from the outside in a direction opposite to the exhaust gas swirl flow.   The secondary combustion gas inlet receives a part of the exhaust gas after dust removal discharged from the secondary combustion chamber together with air as a recirculated exhaust gas to generate a secondary combustion gas to generate the secondary combustion gas. The waste incinerator according to claim 1 or 2, wherein gas is blown into the secondary combustion chamber. A combustion chamber of an incinerator that incinerates waste, and a secondary combustion chamber that receives and combusts an exhaust gas containing a combustible gas from the combustion chamber, and the secondary combustion chamber receives the exhaust gas from the combustion chamber. The exhaust gas inlet that flows into the next combustion chamber is on the lower side, the exhaust gas outlet that discharges the exhaust gas after secondary combustion is on the upper side, and the secondary combustion gas inlet is in the height direction between the exhaust gas inlet and the exhaust gas outlet. In the waste incineration method by the waste incinerator that each has in the middle position between,
Exhaust gas flows into the secondary combustion chamber from an exhaust gas inlet provided at a position radially deviated from the central axis of the secondary combustion chamber, and a one-way exhaust gas swirl flow is generated in the horizontal plane in the secondary combustion chamber. Give rise to
With the spiral guide vane provided in the secondary combustion chamber, the exhaust gas swirl flow is guided upward,
Waste from a waste incinerator provided to blow secondary combustion gas from the outside into the secondary combustion chamber in the same direction as the exhaust gas swirl flow from the secondary combustion gas blowing port Incineration method. A combustion chamber of an incinerator that incinerates waste, and a secondary combustion chamber that receives and combusts an exhaust gas containing a combustible gas from the combustion chamber, and the secondary combustion chamber receives the exhaust gas from the combustion chamber. The exhaust gas inlet that flows into the next combustion chamber is on the lower side, the exhaust gas outlet that exhausts the exhaust gas after secondary combustion is on the upper side, and the gas inlet for secondary combustion is in the height direction. In the waste incineration method by the waste incinerator that each has in the middle position between,
Exhaust gas flows into the secondary combustion chamber from an exhaust gas inlet provided at a position radially deviated from the central axis of the secondary combustion chamber, and a one-way exhaust gas swirl flow is generated in the horizontal plane in the secondary combustion chamber. Give rise to
With the spiral guide vane provided in the secondary combustion chamber, the exhaust gas swirl flow is guided upward,
Waste from a waste incinerator provided to inject secondary combustion gas from the outside into the secondary combustion chamber in the direction opposite to the exhaust gas swirl flow from the secondary combustion gas inlet Incineration method.   Part of the exhaust gas after dust removal discharged from the secondary combustion chamber is received as a recirculated exhaust gas and mixed with air to generate a secondary combustion gas, and the secondary combustion gas is injected into the secondary combustion gas inlet. The waste incinerator according to claim 4 or 5, which is blown into the secondary combustion chamber.

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