JP2006329480A - Combustion furnace device and combustion method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a combustion furnace device and a combustion method capable of stabilizing a flame position in the combustion furnace. <P>SOLUTION: This combustion furnace device comprises a main combustion area detecting means 11 for detecting a position of a main combustion area by detecting temperature distribution in the vertical direction in a combustion chamber, an oxygen concentration adjusting means 16 for adjusting oxygen concentration of an oxygen-containing gas jetted from a nozzle, a partial pre-mixing means 13 for mixing the oxygen-containing gas to a combustible gas supply pipe 2, and a control means 12. The control means 12 lowers the oxygen concentration of the oxygen-containing gas jetted from the nozzle by the oxygen concentration adjusting means 16, and increases the supply quantity of oxygen-containing gas to the combustible gas supply pipe by the partial pre-mixing means when the main combustion area detected by the main combustion area detecting means is moved to an upper portion with respect to a prescribed position. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a combustion furnace apparatus and a combustion method, and more particularly to a combustion furnace apparatus and a combustion method for performing secondary combustion treatment of primary combustion exhaust gas generated in the process of incineration and melting of waste with stable and low pollution.

As this type of apparatus, one disclosed in Patent Document 1 is known. In the apparatus of Patent Document 1, combustible gas generated in a waste melting furnace is sent from a main burner at the lower part upstream to the vertical combustion chamber, and the secondary combustion is performed with primary air, and the exhaust pipe is formed at the upper part on the downstream side. Is discharged as exhaust gas. At a position between the main burner and the exhaust pipe, a plurality of nozzles for blowing secondary air for dilution / mixing are provided in a tangential direction, and a swirling flow is generated in the combustion chamber by the secondary air. Due to this swirling flow, the combustible gas is well stirred with air and the combustibility is improved.
JP 2005-003285 A

  However, in the apparatus of Patent Document 1, secondary combustion may become unstable due to fluctuations in the state of the primary combustion exhaust gas, and improvements are desired.

  A combustion furnace for secondary combustion is directly connected to a combustion furnace or melting furnace for primary combustion, and the generated primary combustion exhaust gas is often accepted as a combustible gas as it is.

  Accordingly, the amount of primary combustion exhaust gas generated, the temperature, and the components also vary depending on the amount of waste input to the combustion furnace or melting furnace or the characteristics thereof. However, the apparatus of Patent Document 1 does not have any means for dealing with these fluctuations in secondary combustion.

  As a result, due to the fluctuation of the primary combustion exhaust gas, the combustion in the combustion furnace as the secondary combustion becomes unstable, the flame moves upward, the upper part of the furnace becomes abnormally high temperature, damages the furnace inner wall, To shorten the service life.

  In view of such circumstances, the present invention stabilizes the flame position of combustion in a combustion furnace that performs secondary combustion using this as a combustible gas even if the generation amount and components of the primary combustion exhaust gas vary, and the combustion furnace An object of the present invention is to provide a combustion furnace apparatus and a combustion method that can be used with a long life.

  In the combustion furnace apparatus according to the present invention, a combustible gas supply pipe is jetted in a lower part which is an upstream side, an exhaust pipe is jetted in an upper part which is a downstream side, and an oxygen-containing gas is jetted in an intermediate part. Nozzles for forming a swirl flow in the combustion chamber are respectively connected.

  In such a combustion furnace apparatus, the present invention is characterized by comprising main combustion region detection means for detecting a temperature distribution in the vertical direction in the combustion chamber.

In the present invention having such a configuration, when the exhaust gas obtained from the primary combustion is subjected to secondary combustion in the combustion chamber as combustible gas, the supply amount / component of the combustible gas fluctuates, and normal combustion is stopped, and the flame is predetermined. When it has risen from the position, the main combustion region detecting means can know this from the detected temperature distribution. In this case, for example, after reducing the oxygen concentration of the oxygen-containing gas for forming the swirling flow to reduce the flame propagation speed at the peripheral edge of the furnace, the combustible supplied at a lower position than the swirling flow. By mixing the oxygen-containing gas into the gas, the flame is pulled back to the lower center of the furnace.

  In the present invention, the main combustion region detection means may have temperature sensors provided at a plurality of positions in the vertical direction on the furnace body. The temperature distribution is known from the detected temperatures of the plurality of temperature sensors, and it is determined that the flame has moved upward in comparison with the predetermined temperature distribution and is abnormally burning.

  In the present invention, in addition to the main combustion region detecting means, an oxygen concentration adjusting means for adjusting the oxygen concentration of the oxygen-containing gas ejected from the nozzle, a partial premixing means for mixing the oxygen-containing gas into the combustible gas supply pipe, Control means, and when the main combustion area detected from the temperature distribution detected by the main combustion area detection means is moving above a predetermined position, the control means uses the oxygen concentration adjustment means to make a nozzle. After reducing the oxygen concentration of the oxygen-containing gas ejected from the furnace and lowering the flame propagation speed at the peripheral edge of the furnace, the oxygen-containing gas supply amount to the combustible gas supply pipe is increased by the partial premixing means. Try to increase the flame propagation speed in the center. Thus, the abnormally raised flame is pulled back to the predetermined position. Here, the oxygen necessary to burn the combustible gas is obtained by ejecting the oxygen-containing gas from a nozzle for forming a swirl flow in the combustion chamber and premixing the oxygen-containing gas into the supplied combustible gas. Have been supplied.

  Alternatively, in the present invention, in addition to the main combustion region detecting means, it has a high temperature gas blowing means for blowing high temperature gas into the furnace center in the vertical direction and a control means, and the control means is a main combustion region detecting means. When the main combustion region detected from the detected temperature distribution is moving above a predetermined position, the oxygen concentration of the oxygen-containing gas ejected from the nozzle by the oxygen concentration adjusting means is reduced, and the high temperature gas blowing means It is also possible to blow in hot gas. This also brings the flame back to the predetermined position.

  The present invention provides a furnace body having an internal space as a combustion chamber, a combustible gas supply pipe in the lower part on the upstream side, an exhaust pipe in the upper part on the downstream side, and an oxygen-containing gas in the middle part. The combustion method by the combustion furnace apparatus to which the nozzles for forming each are connected is also detected, and the position of the main combustion region is detected by detecting the vertical temperature distribution in the combustion chamber, and the detected main combustion region Is moved upward from a predetermined position, after reducing the oxygen concentration of the oxygen-containing gas ejected from the nozzle, or partially premixed oxygen-containing gas to the combustible gas from the combustible gas supply pipe, Alternatively, by blowing high temperature gas upward in the center of the furnace, the flame is pulled back to the center of the furnace, and then the oxygen concentration of the oxygen-containing gas ejected from the nozzle is increased to return the main combustion region to a predetermined position.

  By detecting the temperature distribution in the vertical direction in the combustion chamber as described above, the present invention knows that the flame is moving upward from a predetermined position, and suppresses combustion at the peripheral edge of the furnace and By accelerating the combustion in the center of the furnace, the flame is pulled back to a predetermined position while avoiding a rapid increase in the pressure in the furnace, thereby making the combustion stable and normal. As a result, damage to the furnace due to abnormal combustion can be avoided, repair costs can be reduced, and combustion with low pollution is possible. Further, in the present invention, it is possible to automate the detection and return of the flame position abnormality, and the monitoring operation of the apparatus is simplified by the automation.

  Hereinafter, an embodiment of the present invention will be described with reference to FIG. 1 of the accompanying drawings.

  In FIG. 1, reference numeral 1 denotes a vertical secondary combustion furnace in which a combustion chamber is formed. The secondary combustion furnace 1 is connected to a combustible gas supply pipe 2 provided at a lower portion, for example, a waste incinerator or the like. The exhaust gas generated in the primary combustion furnace 3 is received as combustible gas.

  The secondary combustion furnace 1 is provided with a dust discharge portion 4 at the lower portion, and the dust discharge portion 4 is connected to a dust treatment device 5. The upper part of the secondary combustion furnace 1 is an exhaust part 6, and is connected to a chimney 9 via an exhaust pipe 6A through an exhaust gas treatment device 7 and a smoke exhaust device 8 such as a fan.

  The secondary combustion furnace 1 is provided with a plurality of temperature sensors 10 </ b> A to 10 </ b> H at appropriate intervals on the side wall from the lower end side that is the upstream side to the upper end side that is the downstream side. 10H is connected so that a detection signal is sent to the main combustion region detection device 11, and the main combustion region detection device 11 obtains a temperature distribution in the vertical direction in the combustion chamber from the detection signal to detect the main combustion region. The position is detected. The main combustion region detection device 11 is connected to the control device 12, and compares the main combustion region and the detected main combustion region position under a predetermined condition, and the control device 12 sends control signals to various devices described later. It comes to emit.

  A mixer 13 is connected to an intermediate portion of the secondary combustion furnace 1, and air and exhaust gas as an oxidant are mixed in the mixer 13, and the mixed gas enters the secondary combustion furnace 1. It comes to be injected. The mixed gas from the mixer 13 is injected from the tangential nozzle and forms a swirling flow in the combustion chamber.

  The air to the mixer 13 is taken in from the outside air by the blower 14. At this time, the air flow rate is measured by the flow meter 15, and the flow rate is adjusted by the adjustment valve 16 as oxygen concentration adjusting means.

  On the other hand, the exhaust gas to the mixer 13 passes through a flow path branched from the outlet side of the smoke exhaust device 8, and a part of the exhaust gas is sent to the mixer 13 by the blower 17. At that time, the flow rate of the exhaust gas is measured by the flow meter 18 and the flow rate is adjusted by the adjusting valve 19. This adjustment is made based on the command signal of the control device 12.

  The various members for air intake and exhaust gas intake into the mixer 13 form an oxygen concentration adjusting device 20 as collectively shown by a one-dot chain line in FIG.

  In the secondary combustion apparatus of the present embodiment having such a configuration, combustion in the combustion chamber, particularly control of the position of the flame, is performed as follows.

  (1) In the primary combustion furnace 3, combustible material-containing exhaust gas generated by incineration of waste or the like is supplied from the combustible gas supply pipe 2 into the combustion chamber.

  (2) On the other hand, from the mixer 13, the air taken in from the outside air as an oxidant and a part of the exhaust gas are mixed from the exhaust pipe, and jetted into the combustion chamber. This ejected exhaust gas forms a swirling flow in the combustion chamber.

  (3) The combustible gas supplied into the combustion chamber is mixed with the swirl flow and burns mainly in the lower portion of the combustion chamber. In this normal combustion state, the main combustion region is located in the lower part of the combustion chamber, and a temperature distribution is formed in which this region has the highest temperature in the vertical direction.

(4) When the combustion in the primary combustion furnace 3 fluctuates and the amount and components of the exhaust gas from the primary combustion furnace 3 supplied as the combustible gas to the secondary combustion furnace 1 fluctuate, Combustion may become unstable, in which case the flame moves upward, i.e. the main combustion region moves upward.
As a result, the combustion of the combustible gas becomes unstable, the risk of misfire increases, and the concentration of CO and HC in the exhaust gas increases.

  (5) The temperature distribution in the vertical direction in the combustion chamber under such movement of the main combustion region is known by the main combustion region detection device 11 based on detection signals from the plurality of temperature sensors 10A to 10H. be able to. The detection signals of the temperature sensors 10A to 10H create a temperature distribution by the main combustion region detection device 11 to detect the position of the main combustion region, and the position of the main combustion region is a predetermined position set by the control device 12 The control device 12 issues a command signal based on the result. When the detected position of the main combustion region is moving upward with respect to the predetermined position, the control device 12 increases the opening of the adjustment valve 19 to increase the amount of exhaust gas to the mixer 13. The oxygen concentration of the gas from the mixer 13 is lowered, the propagation speed of the flame at the peripheral edge of the furnace is lowered, and as a result, the main combustion region of the flame is determined while avoiding a rapid rise in the furnace pressure. Pull back to the position. This control may be performed by an operator's operation without using the control device 12.

  The present invention is not limited to the illustrated example, and various modifications can be made. For example, when the main combustion region of the flame is above a predetermined position, as described above, the opening of the adjustment valve 19 is increased to increase the amount of exhaust gas supplied to the combustion chamber via the mixer 13. At the same time, the amount of oxygen (air) of the oxygen-containing gas fed into the combustion chamber together with the combustible gas from the combustible gas supply pipe 2 may be increased to bring the flame back to a predetermined position. For example, a part of the air sent to the mixer 13 is brought to a double pipe nozzle 23 as a partial premixing means via a flow meter 21 and a regulating valve 22 as seen by a two-dot chain line in FIG. Thus, it can be mixed with the exhaust gas from the primary combustion furnace 3 and supplied to the combustion chamber. Thus, the flame is pulled back downward. The opening degree of the adjusting valve 22 is controlled by the control device 12 as indicated by a two-dot chain line in FIG.

  Furthermore, instead of the control by increasing the amount of oxygen to the combustible gas supply pipe 2, a high temperature gas blowing means may be provided to blow the high temperature gas into the lower part of the combustion chamber. For example, as shown by a broken line in FIG. 1, a heater 24 and a nozzle 25 are provided as high-temperature gas blowing means controlled by the control device 12, and the gas is preheated by the heater 24, and the nozzle 25 To the lower center of the combustion chamber. With this high-temperature gas, the flame can be pulled back to a predetermined position while avoiding a rapid rise in the pressure in the furnace near the lower center of the combustion chamber. The heater 24 may be one that exchanges heat from the exhaust gas discharged from the furnace body 1, or may be variously used such as one that exchanges heat by burning fuel.

It is a schematic block diagram of the apparatus of one Embodiment of this invention.

Explanation of symbols

1 Furnace 2 Combustible gas supply pipe (double pipe nozzle)
6A Exhaust pipe 10A to 10H Temperature sensor 11 Main combustion region detection device (means)
12 Control means 13 Partial premixing means 16 Oxygen concentration adjusting means (regulating valve)
24 Hot gas blowing means (heater)
25 High-temperature gas blowing means (nozzle)

Claims (3)

  To form a swirling flow in the combustion chamber with a combustible gas supply pipe in the lower part on the upstream side, an exhaust pipe in the upper part on the downstream side, and an oxygen-containing gas in the middle part in the furnace body with the internal space as the combustion chamber In the combustion furnace apparatus to which each nozzle is connected, main combustion region detection means for detecting the temperature distribution in the vertical direction in the combustion chamber to detect the position of the main combustion region, and the oxygen-containing gas ejected from the nozzle An oxygen concentration adjusting means for adjusting the oxygen concentration; a partial premixing means for mixing the oxygen-containing gas into the combustible gas supply pipe; and a control means, the control means being the main combustion area detecting means. When the combustion region is moving above a predetermined position, the oxygen concentration of the oxygen-containing gas ejected from the nozzle is reduced by the oxygen concentration adjusting means, and the oxygen-containing gas is supplied to the combustible gas supply pipe by the partial premixing means. Combustion furnace apparatus characterized by being configured allowed to increase the supply amount.   In order to form a swirling flow in the combustion chamber with a combustible gas supply pipe in the lower part on the upstream side, an exhaust pipe in the upper part on the downstream side, and an oxygen-containing gas in the middle part in the furnace body with the internal space as the combustion chamber In the combustion furnace apparatus to which each nozzle is connected, main combustion region detection means for detecting the temperature distribution in the vertical direction in the combustion chamber to detect the position of the main combustion region, and the oxygen-containing gas ejected from the nozzle An oxygen concentration adjusting means for adjusting the oxygen concentration, a high temperature gas blowing means for blowing a high temperature gas upward into the center of the furnace, and a control means, the control means being the main combustion detected by the main combustion region detecting means When the area is moving above the specified position, the oxygen concentration of the oxygen-containing gas ejected from the nozzle is reduced by the oxygen concentration adjusting means, and hot gas is blown from the hot gas blowing means. Combustion furnace apparatus characterized by being.   To form a swirling flow in the combustion chamber with a combustible gas supply pipe in the lower part on the upstream side, an exhaust pipe in the upper part on the downstream side, and an oxygen-containing gas in the middle part in the furnace body with the internal space as the combustion chamber In a combustion method using a combustion furnace apparatus to which each nozzle is connected, the vertical temperature distribution in the combustion chamber is detected to detect the position of the main combustion area, and the detected main combustion area moves above a predetermined position. While reducing the oxygen concentration of the oxygen-containing gas ejected from the nozzle, either partially premix the oxygen-containing gas into the combustible gas from the combustible gas supply pipe, or heat upward to the center of the furnace A combustion method characterized by returning a flame to the center of the furnace by blowing gas and then returning the main combustion region to a predetermined position by increasing the oxygen concentration of the oxygen-containing gas ejected from the nozzle.

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