JP4103722B2 - Multistage tubular flame burner and its combustion control method - Google Patents

Description

  The present invention relates to a burner provided in a furnace or a combustor.

  A burner provided in a furnace or a combustor has a tubular combustion chamber with one end opened, and a nozzle for blowing fuel gas and a nozzle for blowing oxygen-containing gas in the vicinity of the closed end of the combustion chamber are provided inside the combustion chamber. A tubular flame burner provided in the tangential direction of the peripheral surface is shown (for example, see Patent Document 1).

In this tubular flame burner, a stable flame is formed in the burner in a high-speed swirling flow, so that downsizing of the combustion equipment is achieved, the temperature variation of the combustion flame is small, and a local high temperature region is generated. In addition to being difficult to form, the burner is capable of stable combustion even when the oxygen ratio or air ratio is lowered. Therefore, the burner can reduce environmental pollution sources such as harmful substances such as NOx, unburned components such as hydrocarbons, and smoke.
JP-A-11-281015

  However, the above tubular flame burner has the following problems.

  That is, in the above-described tubular flame burner, in order to form a tubular flame, a supply nozzle flattened in the tube axis direction is connected to a slit in the tube axis direction provided in the tubular combustion chamber, and blown in the tangential direction. Fuel gas and oxygen-containing gas are blown into the tubular combustion chamber while swirling. Therefore, there exists a problem that the pressure loss in a slit part becomes comparatively high. In other words, since the supply pressure of the fuel gas and the oxygen-containing gas is usually fixed, when the combustion load is increased, it is necessary to increase the flow rates of the fuel gas and the oxygen-containing gas. The pressure loss in the slit portion also increases in proportion to the power, and the combustion load cannot be increased so much.

  In addition, if the slit cross-sectional area is made large in order to reduce the pressure loss of the slit portion, the tangential direction with respect to the combustion chamber peripheral surface when the flow rate of the fuel gas and oxygen-containing gas is reduced to cope with a small combustion load. However, the fuel gas and the oxygen-containing gas injection speed are significantly reduced, and a tubular flame cannot be formed. On the contrary, there is a disadvantage that the generation amount of NOx, soot and the like increases.

  As described above, in the conventional tubular flame burner, when the supply flow rate of the fuel gas and the oxygen-containing gas is increased or decreased in response to the increase or decrease of the combustion load, the minimum flame formation flow velocity and pressure necessary for forming the tubular flame are obtained. In some cases, it is not possible to obtain an appropriate blowing speed between the maximum allowable flow velocity determined by the loss, it is difficult to perform stable combustion over a wide combustion load range, and the applicable combustion load range is limited. .

  The present invention has been made in order to solve the above-described problems, and is a tubular flame burner that enables stable combustion in a wider combustion load range in a tubular flame burner that forms a tubular flame in a tubular combustion chamber. It is an object of the present invention to provide a combustion control method therefor.

  In order to solve the above problems, the present invention has the following features.

[1] A tubular combustion chamber having an open end and a nozzle having a nozzle injection port opened on the inner surface of the combustion chamber and injecting fuel and oxygen-containing gas separately or premixed, and the injection direction of each nozzle Using a plurality of tubular flame burners that are substantially aligned with the tangential direction of the circumferential surface of the combustion chamber, and at the rear end of the tubular flame burner with the larger inner diameter of the combustion chamber, the tip of the tubular flame burner with the smaller inner diameter of the combustion chamber A multi-stage tubular flame burner characterized in that it can be switched between use and stop of individual tubular flame burners constituting a multi-stage tubular flame burner.

[2] A tubular combustion chamber having an open end, a nozzle having a nozzle injection port opened on the inner surface of the combustion chamber, and injecting fuel and oxygen-containing gas separately or premixed, and an injection direction of each nozzle Using a plurality of tubular flame burners that are substantially aligned with the tangential direction of the circumferential surface of the combustion chamber, and at the rear end of the tubular flame burner with the larger inner diameter of the combustion chamber, the tip of the tubular flame burner with the smaller inner diameter of the combustion chamber Is a combustion control method for a multi-stage tubular flame burner which is an integral tubular flame burner so as to be connected to each other,
Depending on the combustion load, the fuel and oxygen-containing gas blowing rate is an appropriate blowing rate between the flame forming minimum flow rate required to form the tubular flame and the allowable maximum flow rate determined from the pressure loss , A combustion control method for a multi-stage tubular flame burner, characterized in that a tubular flame burner to be used is selected from the individual tubular flame burners constituting the multi-stage tubular flame burner and burned.

  According to the present invention, an appropriate tubular flame burner can be selected and used from the multi-stage tubular flame burner in accordance with the increase or decrease of the combustion load, so that stable combustion is performed in a wider combustion load range. It becomes possible.

  One embodiment of the present invention is shown in FIGS. FIG. 1 is a side view of a multistage tubular flame burner used in this embodiment, FIG. 2A is a cross-sectional view taken along the line AA in FIG. 1, and FIG. It is sectional drawing of an arrow. 3 and 4 are explanatory diagrams of the combustion control method for the multistage tubular flame burner according to this embodiment.

  In FIG. 1, 1 is a multi-stage tubular flame burner according to this embodiment, and a large-diameter tubular flame burner 2 having a large inner diameter is followed by a small-diameter tubular flame burner 3 having a small inner diameter connected in series. It has a structure.

  As shown in FIGS. 1 and 2A, the large-diameter tubular flame burner 2 includes a tubular combustion chamber 10 having an open end 10a serving as a combustion gas discharge port, and a fuel gas in the combustion chamber 10. It has nozzles 11a, 11b, 11c, and 11d for blowing oxygen-containing gas separately. In the vicinity of the rear end 10b of the combustion chamber 10, elongated slits 12 along the tube axis direction are formed at four locations on the same circumference of the combustion chamber 10 as nozzle injection ports to the combustion chamber 10. The slits 12 are connected to nozzles 11a, 11b, 11c, and 11d that are elongated in the tube axis direction. The injection directions of the nozzles 11 a, 11 b, 11 c, and 11 d are provided so as to be tangential to the inner peripheral surface of the combustion chamber 10 and in the same rotational direction. Of these four nozzles, two nozzles 11a and 11c are fuel gas blowing nozzles, and two nozzles 11b and 11d are oxygen-containing gas blowing nozzles.

  Fuel gas is blown from the fuel gas blowing nozzles 11 a and 11 c at a high speed toward the tangential direction of the inner circumferential surface of the combustion chamber 10, and oxygen-containing gas is blown from the oxygen-containing gas blowing nozzles 11 b and 11 d to the inner circumference of the combustion chamber 10. A swirling flow is formed while the fuel gas and the oxygen-containing gas are efficiently mixed in a region close to the inner peripheral surface of the combustion chamber 10 while being blown at high speed toward the tangential direction of the surface. When the mixed gas in the swirl flow is ignited by an ignition device (not shown) such as an ignition plug or a pilot burner, a tubular flame is generated in the combustion chamber 10. Then, the combustion gas is discharged from the tip 10 a of the combustion chamber 10.

  On the other hand, as shown in FIGS. 1 and 2B, the small-diameter tubular flame burner 3 has a tubular shape in which the tip 13a is connected to the rear end 10b of the large-diameter tubular flame burner 2 and serves as a combustion gas discharge port. Combustion chamber 13 and nozzles 14a, 14b, 14c, and 14d for separately blowing fuel gas and oxygen-containing gas into combustion chamber 13 are provided. In the vicinity of the rear end 13b of the combustion chamber 13, elongated slits 15 along the tube axis direction are formed at four locations on the same circumference of the combustion chamber 13 as nozzle injection ports to the combustion chamber 13. The slits 15 are connected to flat nozzles 14a, 14b, 14c, 14d that are elongated in the tube axis direction. The injection directions of the nozzles 14 a, 14 b, 14 c, and 14 d are provided so as to be tangential to the inner peripheral surface of the combustion chamber 13 and in the same rotational direction. Of these four nozzles, two of the nozzles 14a and 14c are fuel gas injection nozzles, and two of the nozzles 14b and 14d are oxygen-containing gas injection nozzles.

  In correspondence with the larger inner diameter of the combustion chamber 10 of the large diameter tubular flame burner 2, the opening area of the slit 12 of the large diameter tubular flame burner 2 is larger than the opening area of the slit 15 of the small diameter tubular flame burner 3. It is larger than that.

  Fuel gas is blown from the fuel gas blowing nozzles 14 a and 14 c at a high speed toward the tangential direction of the inner peripheral surface of the combustion chamber 13, and oxygen-containing gas is blown from the oxygen-containing gas blowing nozzles 14 b and 14 d to the inner circumference of the combustion chamber 13. A swirling flow is formed while the fuel gas and the oxygen-containing gas are efficiently mixed in a region close to the inner peripheral surface of the combustion chamber 13 while being blown at a high speed in the tangential direction of the surface. When the mixed gas in the swirl flow is ignited by an ignition device (not shown) such as an ignition plug or a pilot burner, a tubular flame is generated in the combustion chamber 13. The combustion gas is discharged from the tip 10 a from the tip 13 a of the combustion chamber 13 through the combustion chamber 10 of the large diameter tubular flame burner 2.

  The oxygen-containing gas mentioned above refers to a gas that supplies oxygen for combustion, such as air, oxygen, oxygen-enriched air, oxygen / exhaust gas mixture gas.

  As shown in FIG. 3, an on-off valve 16a for turning on and off the supply of the fuel gas to the nozzles 11a and 11c is provided in the pipe for supplying the fuel gas to the fuel gas injection nozzles 11a and 11c of the large-diameter tubular flame burner 2. In the pipe for supplying oxygen-containing gas to the oxygen-containing gas blowing nozzles 11b, 11d of the large-diameter tubular flame burner 2, an on-off valve 16b that turns on and off the supply of the oxygen-containing gas to the nozzles 11b, 11d. Is provided. Therefore, use and stop of the large-diameter tubular flame burner 2 can be switched by opening and closing the on-off valves 16a and 16b.

  Further, in the pipe for supplying fuel gas to the fuel gas blowing nozzles 14a and 14c of the small diameter tubular flame burner 3, an on-off valve 17a for turning on and off the supply of the fuel gas to the nozzles 14a and 14c is provided. In the piping for supplying oxygen-containing gas to the oxygen-containing gas blowing nozzles 14b and 14d of the flame burner 3, an on-off valve 17b for turning on and off the supply of the oxygen-containing gas to the nozzles 14b and 14d is provided. Therefore, the use and stop of the small diameter tubular flame burner 3 can be switched by opening and closing the on-off valves 17a and 17b.

  And the supply control apparatus 20 for controlling opening and closing of the on-off valve 16a, 16b, 17a, 17b is provided, and the tubular flame burner to be used can be selected now by the on-off control.

  The fuel gas supply pipe is provided with a fuel gas flow rate adjusting valve 18 for adjusting the overall flow rate of the fuel gas supplied to the fuel gas blowing nozzles 11a, 11c, 14a, 14c, and contains oxygen. An oxygen-containing gas flow rate adjusting valve 19 for adjusting the overall flow rate of the oxygen-containing gas supplied to the oxygen-containing gas blowing nozzles 11b, 11d, 14b, and 14d is provided in the gas supply pipe. The fuel gas flow rate adjustment valve 18 and the oxygen-containing gas flow rate adjustment valve 19 are controlled by a supply control device 20 so as to adjust the overall flow rates of the supplied fuel gas and oxygen-containing gas.

  The total supply flow rate of the fuel gas and the oxygen-containing gas is measured by the fuel gas flow meter 21 and the oxygen-containing gas flow meter 22, and the measured value is sent to the supply control device 20 to adjust the fuel gas flow rate. The valve 18 and the oxygen-containing gas flow rate adjusting valve 19 are used for opening degree adjustment.

  A combustion control method for the multistage tubular flame burner 1 configured as described above will be described with reference to FIGS.

  In this multistage tubular flame burner combustion control method, the tubular flame burner to be used is selected from the large diameter tubular flame burner 2 and the small diameter tubular flame burner 3 in accordance with the combustion load.

  That is, the large-diameter tubular flame burner 2 and the small-diameter tubular flame burner 3 are each supplied with a supply flow rate at which the blowing speed becomes a minimum flame formation flow velocity necessary for forming a tubular flame and an allowable maximum flow velocity determined from pressure loss. The range of the combustion load corresponding to the range of the flow rate is the combustible range, but the small-diameter tubular flame burner 3 has a relatively small combustion load range because the internal diameter of the combustion chamber is small and the opening area of the slit is small. Since the large-diameter tubular flame burner 2 has a large inner diameter and a large opening area of the slit, a relatively large combustion load range is the combustible range.

  Therefore, when the combustion load is small, the small-diameter tubular flame burner 3 is used. When the combustion load increases, the large-diameter tubular flame burner 2 is used. When the combustion load increases further, the large-diameter tubular flame burner 2 and the small-diameter tubular flame burner are used. Use flame burner 3 together.

  Thus, in this embodiment, stable combustion in a wide combustion load range, which is difficult with a single tubular flame burner, is possible.

  Next, another embodiment of the present invention will be described with reference to FIG.

  In the above-described embodiment, as shown in FIG. 3, the overall flow rate of the fuel gas supplied to the large-diameter tubular flame burner 2 and / or the small-diameter tubular flame burner 3 and the overall flow rate of the oxygen-containing gas are adjusted. In contrast, in this embodiment, the flow rate of the fuel gas to be supplied and the flow rate of the oxygen-containing gas can be adjusted separately for the large diameter tubular flame burner 2 and the small diameter tubular flame burner 3. .

  That is, as shown in FIG. 5, first, in the pipe for supplying the fuel gas to the large-diameter tubular flame burner 2, the fuel gas flow rate for adjusting the flow rate of the fuel gas supplied to the fuel gas blowing nozzles 11a and 11c. An adjustment valve 18a is provided, and an oxygen-containing gas for adjusting the flow rate of the oxygen-containing gas supplied to the oxygen-containing gas blowing nozzles 11b and 11d is provided in the pipe for supplying the oxygen-containing gas to the large-diameter tubular flame burner 2. A gas flow rate adjusting valve 19a is provided. The fuel gas flow rate adjusting valve 18a and the oxygen-containing gas flow rate adjusting valve 19a are controlled by a supply control device 20a so that the flow rates of the fuel gas and the oxygen-containing gas supplied to the large-diameter tubular flame burner 2 can be adjusted. The supply flow rates of the fuel gas and the oxygen-containing gas are measured by the fuel gas flow meter 21a and the oxygen-containing gas flow meter 22a. The measured values are sent to the supply control device 20a, and the fuel gas flow rate adjusting valve 18a and It is used for adjusting the opening of the oxygen-containing gas flow rate adjusting valve 19a.

  Similarly, a fuel gas flow rate adjusting valve 18b for adjusting the flow rate of the fuel gas supplied to the fuel gas blowing nozzles 14a and 14c is provided in the pipe for supplying the fuel gas to the small diameter tubular flame burner 3, An oxygen-containing gas flow rate adjusting valve 19b for adjusting the flow rate of the oxygen-containing gas supplied to the oxygen-containing gas blowing nozzles 14b and 14d is provided in the pipe for supplying the oxygen-containing gas to the small diameter tubular flame burner 3. . The fuel gas flow rate adjustment valve 18b and the oxygen-containing gas flow rate adjustment valve 19b are controlled by a supply control device 20b so that the flow rates of the fuel gas and the oxygen-containing gas supplied to the small diameter tubular flame burner 3 can be adjusted. The supply flow rates of the fuel gas and the oxygen-containing gas are measured by the fuel gas flow meter 21b and the oxygen-containing gas flow meter 22b, and the measured values are sent to the supply control device 20b, and the fuel gas flow rate adjusting valve 18b and It is used for adjusting the opening of the oxygen-containing gas flow rate adjusting valve 19b.

  Then, in cooperation with the supply control device 20a for the large diameter tubular flame burner 2 and the supply control device 20b for the small diameter tubular flame burner 3, the overall supply flow rates of the fuel gas and the oxygen-containing gas can be adjusted.

  When the multi-stage tubular flame burner configured as described above is burned, the fuel gas flow rate adjustment valve 18a and the oxygen-containing gas flow rate adjustment valve 19a of the large diameter tubular flame burner 2 are opened while the combustion load is small. The degree of opening of the fuel gas flow rate adjusting valve 18b and the oxygen-containing gas flow rate adjusting valve 19b of the small-diameter tubular flame burner 3 is adjusted according to the combustion load, and when the combustion load increases, the small-diameter tubular flame burner 3 The opening degrees of the fuel gas flow rate adjusting valve 18b and the oxygen-containing gas flow rate adjusting valve 19b are set to zero, and the opening amounts of the fuel gas flow rate adjusting valve 18a and the oxygen-containing gas flow rate adjusting valve 19a of the large-diameter tubular flame burner 2 are set as combustion loads. Adjust accordingly. When the combustion load further increases, the opening of the fuel gas flow rate adjustment valve 18b and the oxygen-containing gas flow rate adjustment valve 19b of the small-diameter tubular flame burner 3 that has been zeroed is opened, and the large-diameter tubular flame burner 2 according to the combustion load. The opening degrees of the fuel gas flow rate adjustment valve 18a and the oxygen-containing gas flow rate adjustment valve 19a and the opening degrees of the fuel gas flow rate adjustment valve 18b and the oxygen-containing gas flow rate adjustment valve 19b of the small-diameter tubular flame burner 3 are respectively adjusted.

  Thus, also in this embodiment, stable combustion in a wide combustion load range that is difficult with a single tubular flame burner is possible.

  In the embodiments described so far, two tubular flame burners are connected. However, if necessary, three or more tubular flame burners may be connected.

  In the embodiments described so far, the fuel gas injection nozzle and the oxygen-containing gas injection nozzle are provided so that the injection direction coincides with the tangential direction of the combustion chamber peripheral surface. It is not necessary to coincide with the direction, and the injection direction may deviate from the tangential direction of the circumferential surface of the combustion chamber to such an extent that a swirl flow of gas can be formed in the combustion chamber.

  In the embodiments described so far, a slit is provided along the tube axis direction as an injection port to the combustion chamber, and a flat fuel gas injection nozzle and an oxygen-containing gas injection nozzle are connected to the slit. A plurality of small holes may be arranged in the tube axis direction as injection ports to the combustion chamber, and nozzles for injecting fuel gas or oxygen-containing gas may be connected to the small hole row.

  In the embodiments described so far, the fuel gas and the oxygen-containing gas are blown separately, but the fuel gas and the oxygen-containing gas may be blown in a premixed manner.

It is a side view of the multistage type tubular flame burner concerning one embodiment of the present invention. It is AA sectional drawing of FIG. It is explanatory drawing of the combustion control method of the multistage tubular flame burner which concerns on one Embodiment of this invention. It is explanatory drawing of the combustion control method of the multistage tubular flame burner which concerns on one Embodiment of this invention. It is explanatory drawing of other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Multistage type tubular flame burner 2 Large diameter tubular flame burner 3 Small diameter tubular flame burner 10 Combustion chamber of large diameter tubular flame burner 10a Front end of combustion chamber of large diameter tubular flame burner 10b Rear end of combustion chamber of large diameter tubular flame burner 11a 11c Fuel gas injection nozzles 11b, 11d Oxygen-containing gas injection nozzles 12 Slit 13 Combustion chamber of small diameter tubular flame burner 13a Tip of combustion chamber of small diameter tubular flame burner 13b Rear end of combustion chamber of small diameter tubular flame burner 14a, 14c Fuel gas Blowing nozzles 14b, 14d Oxygen-containing gas blowing nozzle 15 Slit 16a Fuel gas on-off valve 16b Oxygen-containing gas on-off valve 17a Fuel gas on-off valve 17b Oxygen-containing gas on-off valve 18, 18a, 18b Fuel gas flow rate adjustment valve 19 19a, 19b Oxygen-containing gas flow control valve 20, 2 a, 20b supply controller 21, 21a, flowmeter 22,22a and 21b the fuel gas flow meter of 22b containing gas

Claims (2)

A tubular combustion chamber having an open end, and a nozzle having a nozzle injection port opened on the inner surface of the combustion chamber, the fuel and the oxygen-containing gas being blown separately or premixed, the injection direction of each nozzle being the combustion chamber Using a plurality of tubular flame burners that substantially coincide with the tangential direction of the peripheral surface, the tip of the tubular flame burner with a smaller inner diameter of the combustion chamber is connected to the rear end of the tubular flame burner with a larger inner diameter of the combustion chamber. Thus, while using it as an integral tubular flame burner, the use and stop of each tubular flame burner which constitute the multi-stage tubular flame burner were made switchable, The multi-stage tubular flame burner characterized by things. A tubular combustion chamber having an open end, and a nozzle having a nozzle injection port opened on the inner surface of the combustion chamber, the fuel and the oxygen-containing gas being blown separately or premixed, the injection direction of each nozzle being the combustion chamber Using a plurality of tubular flame burners that substantially coincide with the tangential direction of the peripheral surface, the tip of the tubular flame burner with a smaller inner diameter of the combustion chamber is connected to the rear end of the tubular flame burner with a larger inner diameter of the combustion chamber. In this way, a combustion control method for a multi-stage tubular flame burner that is an integral tubular flame burner ,
Depending on the combustion load, the fuel and oxygen-containing gas blowing rate is an appropriate blowing rate between the flame forming minimum flow rate required to form the tubular flame and the allowable maximum flow rate determined from the pressure loss , A combustion control method for a multi-stage tubular flame burner, characterized in that a tubular flame burner to be used is selected from the individual tubular flame burners constituting the multi-stage tubular flame burner and burned.

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