JP2019027647A - Pulverized-coal burner - Google Patents

Abstract

To provide a pulverized-coal burner capable of stably igniting and burning pulverized coal without reference to a burner burning amount.SOLUTION: A pulverized-coal burner has opening/closing valves 18a-18f interposed in respective pulverized-coal injection nozzles 10a-10f, and also comprises an opening/closing controller 19 which performs opening/closing control over the respective opening/closing valves 18a-18f based upon an air blow amount of a pressure feed fan 12 that a pulverized-coal pressure feed pipe 13 comprises. Then the opening/closing controller 19 opens and closes the respective opening/closing valves 18a-18f to increase or decrease the number of nozzles to jet pulverized coal, and the jet of the pulverized coal is thus maintained at a flow rate suitable to stable burning without reference to a burner burning amount.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a pulverized coal burner whose main fuel is pulverized coal obtained by carbonizing and pulverizing woody biomass.

  Conventionally, there is a pulverized coal burner in which woody biomass such as waste wood and thinned wood is carbonized and pulverized coal obtained by pulverizing these is co-fired with fuel oil such as heavy oil. The pulverized coal burner can save energy by providing a part of the fuel with relatively inexpensive pulverized coal derived from woody biomass, and can also be expected to reduce CO2 from the viewpoint of carbon neutrality.

  For example, in Patent Document 1 (Japanese Utility Model Publication No. 1-44491), a fuel oil injection nozzle for forming a flame is injected at the center position of a cylindrical burner body, and pulverized coal is injected around the fuel oil injection nozzle. A plurality of pulverized coal injection nozzles arranged at predetermined intervals, and provided with a distributor for distributing and supplying the pulverized coal supplied to the burner body to each of the pulverized coal injection nozzles, a flame formed in front of the fuel oil injection nozzle On the other hand, there is described a pulverized coal burner in which pulverized coal is blown from each of the pulverized coal injection nozzles to be ignited and combusted.

No. 1-444901

  However, in the conventional pulverized coal burner, when the supply amount of pulverized coal increases / decreases in accordance with the burner combustion amount, the pulverized coal injection flow rate from each pulverized coal injection nozzle also increases / decreases accordingly. If the burner has a turndown ratio (ratio of the minimum combustion amount to the maximum combustion amount), the increase / decrease width will be larger. In order to properly ignite and combust the injected pulverized coal, it is necessary to inject at an appropriate injection flow rate with respect to the flame. Like the high turndown ratio burner, the pulverized coal is injected at the maximum and minimum combustion. When the flow rate fluctuates greatly, some device is required.

  In view of the above points, an object of the present invention is to provide a pulverized coal burner capable of stably igniting and burning pulverized coal regardless of the burner combustion amount.

  In the pulverized coal burner according to the first aspect of the present invention, a flame-forming fuel oil injection nozzle provided at substantially the center of a cylindrical burner body, and a plurality of fuel oil injection nozzles provided around the fuel oil injection nozzle at predetermined intervals. Pulverized coal injection nozzles, pulverized coal pressure feed pipes having a pressure feed fan that can adjust the blowing amount according to the burner combustion amount, and the pulverized coal injection nozzles that feed air pressure by the pulverized coal pressure feed pipes. In the pulverized coal burner comprising a distributor for supplying and distributing to the pulverized coal, an opening / closing valve is provided for each pulverized coal injection nozzle, and an opening / closing controller for controlling the opening / closing of the each opening / closing valve based on the air flow rate of the pressure feed fan. The open / close controller opens and closes the open / close valves to increase or decrease the number of nozzles for injecting pulverized coal to maintain the injection speed of pulverized coal at a flow rate suitable for stable combustion.

  Further, in the pulverized coal burner according to claim 2, the open / close controller is configured to open / close the pulverized coal injection nozzles by placing one open / close valve for each of the pulverized coal injection nozzles or interlocking those at symmetrical positions around the fuel oil injection nozzle. It is characterized by that.

  According to the pulverized coal burner according to claim 1 of the present invention, the plurality of pulverized coal injection nozzles arranged around the fuel oil injection nozzle are each provided with an open / close valve, and the blast amount of the pressure feeding fan of the pulverized coal pressure feeding pipe. And an opening / closing controller for controlling the opening / closing of each of the opening / closing valves. The opening / closing controller opens / closes each opening / closing valve to increase / decrease the number of nozzles for injecting pulverized coal, thereby stabilizing the pulverized coal injection flow rate. Therefore, the pulverized coal as the main fuel can be stably ignited and burned regardless of the burner combustion amount.

  Further, according to the pulverized coal burner according to claim 2, the open / close controller opens or closes the pulverized coal injection nozzles with one open / close valve for each pulverized coal injection nozzle or interlocks with the fuel oil injection nozzle at the symmetrical position. Thus, even when the number of nozzles for injecting pulverized coal is reduced, the pulverized coal can be injected evenly with respect to the flame in front of the fuel oil injection nozzle located at the center, and stable ignition combustion can be performed.

It is a schematic explanatory drawing which shows one Example of the pulverized coal burner which concerns on this invention. It is AA sectional drawing which abbreviate | omitted a part of FIG. It is BB sectional drawing which abbreviate | omitted a part of FIG. 1 which shows the state which opened each pulverized coal injection nozzle. It is a figure corresponded in Drawing 3 showing the state where a part of nozzles (every other nozzle) was closed among each pulverized coal injection nozzle. FIG. 4 is a view corresponding to FIG. 3 showing a state in which some of the pulverized coal injection nozzles (symmetrical positions with respect to the fuel oil injection nozzle) are closed.

  In the pulverized coal burner according to the present invention, a fuel oil injection nozzle for forming a flame provided at a substantially central portion of a cylindrical burner body, and a predetermined interval so as to surround the periphery of the fuel oil injection nozzle. A plurality of pulverized coal injection nozzles, a pulverized coal pressure feed pipe having a pressure feed fan that makes it possible to adjust an air flow rate according to the burner combustion amount, and pulverized coal that is air-fed by the pulverized coal pressure feed tube. And a distributor for distributing and supplying to the injection nozzle.

  In addition, an opening / closing valve is provided in the middle of each pulverized coal injection nozzle, and the opening / closing control is performed to control opening / closing of each opening / closing valve based on the amount of air blown from the pressure feed fan of the pulverized coal pressure feed pipe (pulverized coal supply amount). The number of nozzles for injecting pulverized coal is increased or decreased by opening and closing each open / close valve with the opening / closing controller, and the injection flow rate is commensurate with stable combustion regardless of the amount of pulverized coal injection (burner combustion amount). To maintain the correct flow rate.

  Note that the flow rate suitable for the stable combustion mentioned here means that the pulverized coal is blown into at least the flame region formed in front of the fuel oil injection nozzle, and the pulverized coal thus blown completely ignites before passing through the flame region. Although it is the speed range that can be burned, the properties of pulverized coal (ignitability, combustibility, etc.) obtained by carbonization and pulverization of woody biomass are expected to vary somewhat, so combustion tests etc. It is good to adjust as appropriate.

  Preferably, the open / close controller controls the open / close valves of the pulverized coal injection nozzles so that they are opened or closed in conjunction with each other at symmetrical positions around the fuel oil injection nozzle. By adopting the above control, even when the number of nozzles for injecting pulverized coal during low combustion is reduced, pulverized coal can be blown in a well-balanced manner from the surroundings with respect to the flame in front of the fuel oil injection nozzle and stably combusted. .

  Then, during operation of the pulverized coal burner having the above-described configuration, an amount of pulverized coal corresponding to the burner combustion amount is cut out, air-fed by the pressure-feeding fan with an air blowing amount corresponding to the cut-out amount, and each through the distributor It is injected from the pulverized coal injection nozzle and blown into the flame formed in front of the fuel oil injection nozzle to be ignited and burned. At this time, the opening / closing controller sequentially takes in the blown amount of the pressure feeding fan, and opens / closes each open / close valve interposed in each of the pulverized coal injection nozzles according to the blown amount, thereby injecting pulverized coal. Adjusting and maintaining the injection flow rate to a flow rate suitable for stable combustion.

  Thus, according to the pulverized coal burner, even if the supply amount of the pulverized coal is increased or decreased according to the burner combustion amount, the injection flow rate of the pulverized coal from each pulverized coal injection nozzle is changed to the flame in front of the fuel oil injection nozzle. On the other hand, it can be adjusted so as to always blow at an appropriate speed, and the pulverized coal can be stably ignited and burned regardless of the burner combustion amount.

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

  In the figure, reference numeral 1 denotes a pulverized coal burner using pulverized coal as a main fuel. The pulverized coal burner includes a cylindrical burner body 2, and a throat 3 having a substantially frustoconical shape is connected to the tip of the burner body 2. On the other hand, a blower 5 for supplying combustion air is connected to the rear end portion via a blower duct 4. The drive motor 6 of the blower 5 is provided with an inverter (not shown) for adjusting the rotational speed, and by adjusting the rotational speed of the drive motor 6 with the inverter, combustion commensurate with the burner combustion amount. The working air amount can be sucked from the intake port 7 and supplied to the burner body 2.

  The burner body 2 is provided with a fuel oil injection nozzle 8 for forming a flame using heavy oil or the like as a fuel at a substantially central portion (cylindrical shaft core portion), and the throat 3 at a position in front of the fuel oil injection nozzle 8. Inside, an annular flame holding plate 9 having a diameter slightly larger than the inner diameter of the burner body 2 is provided. In addition, as shown in FIG. 2, a plurality of, for example, about 4 to 8 concentric circles around the fuel oil injection nozzle 8 are formed around the fuel oil injection nozzle 8 at a predetermined interval (in this embodiment, for example). 6) pulverized coal injection nozzles 10a to 10f.

  As shown in FIG. 1, each of the pulverized coal injection nozzles 10a to 10f has a substantially L-shaped curved pipe structure, the tip of which penetrates the flame holding plate 9, and the tip of the fuel oil injection nozzle 8 The pulverized coal that is extended forward from the pulverized coal injection nozzles 10a to 10f is blown into the flame region formed in the throat 3 in front of the fuel oil injection nozzle 8, while the base end portion is The burner main body 2 is bent at a substantially right angle and connected to the distributor 11.

  The distributor 11 is arranged behind the fuel oil injection nozzle 8 and has a hollow cylindrical shape having the same axis as the burner body 2, and pulverized coal having a pressure feed fan 12 at the rear end of the distributor 11. While the pressure feed pipe 13 is directly connected, the base end portions of the pulverized coal injection nozzles 10a to 10f are substantially radially connected to the outer peripheral surface of the cylindrical portion of the distributor 11 at a predetermined interval. By supplying the pulverized coal fed by air from the pressure feeding pipe 13 via the distributor 11, the pulverized coal injection nozzles 10a to 10f can be distributed and supplied substantially evenly.

  Reference numeral 14 in FIG. 1 denotes a pulverized coal storage bin for storing pulverized coal as burner fuel obtained by carbonizing and pulverizing woody biomass, for example, at the lower end of the pulverized coal storage bin 14. A rotary valve 15 capable of cutting out pulverized coal in an amount corresponding to the combustion amount is provided, and a discharge port 16 at a lower portion of the rotary valve 15 and the pulverized coal pressure feed pipe 13 are connected to the rotary valve 15. The pulverized coal to be cut out is fed by air from the pressure feed fan 12 and can be supplied to the pulverized coal injection nozzles 10a to 10f via the pulverized coal pressure feed pipe 13 and the distributor 11.

  The pressure feed fan 12 is provided with an inverter 17 that is an air flow rate adjusting means, and when the amount of pulverized coal cut out by the rotary valve 15 below the pulverized coal storage bin 14 is increased or decreased according to the burner combustion amount, the inverter 17 Thus, the air flow is adjusted to the amount corresponding to the pulverized coal cut-out amount after increase / decrease.

  Further, opening / closing valves 18a to 18f are interposed in the middle of the pulverized coal injection nozzles 10a to 10f, respectively, and the blast amount (pulverized coal supply amount) of the pressure feeding fan 12 provided in the pulverized coal pressure feeding pipe 13 is set. An open / close controller 19 that controls the open / close valves 18a to 18f based on the open / close valves is provided.

  In the opening / closing controller 19, the number of nozzles to be opened among the pulverized coal injection nozzles 10 a to 10 f is set in advance according to the amount of air blown by the pressure feed fan 12. The number of open nozzles is gradually reduced as the air flow rate decreases, and about 1 or 2 are set near the minimum air flow rate. According to the above setting, the pulverized coal injection flow rate can be maintained at a flow rate commensurate with stable combustion, regardless of the increase or decrease in the amount of blown air.

  In the above embodiment, the pulverized coal injection nozzles 10a to 10f are opened and closed in units of one according to the amount of air blown by the pressure feeding fan 12, and the number of open nozzles can be adjusted up and down in a maximum of six stages. However, the present invention is not limited to this. For example, in the case of a relatively small burner that does not need to be adjusted very finely, it can be opened and closed in units of multiple nozzles. The number may be increased / decreased in two to three stages (for example, when the air flow rate is about half or more of the maximum air flow rate, the number is 6 and when it is about half or less, 3 is set).

  Preferably, the number of pulverized coal injection nozzles is an even number of about 4 to 8, and the intervals between the nozzles are equally spaced. In the opening / closing controller 19, when opening / closing the opening / closing valves 18a to 18f of the pulverized coal injection nozzles 10a to 10f, for example, one is placed as shown in FIG. It is good to control so that the thing of a symmetrical position centering | focusing on the injection nozzle 8 may be opened and closed. 3 to 5, the pulverized coal injection nozzle whose nozzle opening is shown in white represents a state in which the open / close valve is opened, and the pulverized coal injection nozzle shown in black represents a state in which the open / close valve is closed. . By adopting the above control, even when the number of nozzles for injecting pulverized coal during low combustion is reduced, the pulverized coal can be blown from the periphery in a well-balanced manner with respect to the flame formed in front of the fuel oil injection nozzle 8.

  And at the time of the operation of the pulverized coal burner 1 having the above-described configuration, the pulverized coal corresponding to the burner combustion amount is cut out from the pulverized coal storage bottle 14 and air-fed by the pumping fan 12 with the blowing amount corresponding to the cut-out amount, The pulverized coal injection pipes 10 and the distributor 11 are used to inject from the pulverized coal injection nozzles 10 a to 10 f and blow into the flame region formed in front of the fuel oil injection nozzle 8 to be ignited and burned.

  At this time, the opening / closing controller 19 sequentially takes in the blowing amount of the pressure feeding fan 12, and the pulverized coal injection nozzles 10a to 10f are set so as to have the number of open nozzles set in advance according to the blowing amount. Are opened and closed to adjust and maintain the pulverized coal injection flow rate at a flow rate suitable for stable combustion.

  Thus, according to the pulverized coal burner 1 of the present invention, for example, even in a burner with a high turndown ratio in which the amount of pulverized coal supplied during low combustion and the injection flow rate are greatly reduced compared to those during high combustion. The pulverized coal injection flow rate can be adjusted and maintained at an appropriate flow rate. Conventionally, pulverized coal can be stably mixed and burned even in low combustion areas where combustion with only fuel oil is unavoidable. The amount of charcoal used can be increased.

  As in this embodiment, all the pulverized coal injection nozzles 10a to 10f may be provided with opening / closing valves 18a to 18f. For example, six nozzles are arranged in two to three stages (for example, 6 at high combustion). In case of opening / closing control with this open, only 3 when low combustion, etc.), it is possible to limit the nozzles that need to be opened / closed (excluded nozzles are always open) An opening / closing valve may be interposed only for the corresponding pulverized coal injection nozzle.

  Further, in the opening / closing controller 19, instead of the amount of air blown by the pressure feed fan 12, the open / close valves 18 a to 18 f of the pulverized coal injection nozzles 10 a to 10 f are based on the cut-out amount of pulverized coal cut by the rotary valve 15. The number of nozzles for injecting pulverized coal may be increased or decreased by opening and closing 18f.

  Also, when heat treatment is performed by supplying hot air generated by the combustion of pulverized coal to the object to be heated, combustion ash is generated on the surface of the object to be heated. For example, an aggregate that is a material of an asphalt mixture that is a road paving material can be used without any problem even if the combustion ash adheres or mixes somewhat. It can suitably be employed as a dryer burner for aggregate heat treatment.

  The present invention is not limited to pulverized coal obtained by carbonizing and pulverizing woody biomass, but pulverized coal using pulverized coal obtained by carbonizing and pulverizing various types of biomass including food waste and livestock manure as fuel. It can be widely used for charcoal burners.

DESCRIPTION OF SYMBOLS 1 ... Pulverized coal burner 2 ... Burner main body 5 ... Blower 8 ... Fuel oil injection nozzle 10a-10f ... Pulverized coal injection nozzle 11 ... Distributor 12 ... Pressure feed fan 13 ... Pulverized coal pressure feed pipe 14 ... Pulverized coal storage bottle 15 ... Rotary valve 17 ... Inverter 18a-18f ... Open / close valve 19 ... Open / close controller

Claims (2)

  A fuel oil injection nozzle for forming a flame provided at substantially the center of the cylindrical burner body, a plurality of pulverized coal injection nozzles provided at predetermined intervals around the fuel oil injection nozzle, and a burner according to the burner combustion amount In a pulverized coal burner comprising a pulverized coal pressure feed pipe having a pressure feed fan that makes air volume adjustable, and a distributor that distributes and supplies the pulverized coal fed by air in the pulverized coal pressure feed pipe to the pulverized coal injection nozzles, Each pulverized coal injection nozzle is provided with an opening / closing valve, and an opening / closing controller that controls opening / closing of each opening / closing valve based on an air flow rate of the pressure feed fan. The opening / closing controller opens / closes each opening / closing valve. A pulverized coal burner characterized in that the number of nozzles for injecting pulverized coal is increased or decreased to maintain the injection flow rate of pulverized coal at a flow rate suitable for stable combustion.   2. The open / close controller according to claim 1, wherein one open / close valve of each of the pulverized coal injection nozzles is placed or opened / closed in conjunction with a symmetric position centering on the fuel oil injection nozzle. Pulverized coal burner.

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