JP5322030B2 - Burner - Google Patents

Description

  The present invention relates to a burner mainly used for a boiler.

  Conventionally, as disclosed, for example, in Patent Document 1 below, a burner having two nozzles, a low combustion nozzle and a high combustion nozzle, is known. In this type of burner, fuel is sprayed from the low combustion nozzle at the time of low combustion, but fuel is not sprayed from the high combustion nozzle, and at the time of high combustion, both the low combustion nozzle and the high combustion nozzle are used. Spray fuel from.

JP 2008-215791 A (FIG. 5)

  Recently, biofuels have attracted attention and are gradually being put into practical use. For example, there is an attempt to produce alcohol using a food residue or the like as fuel for a boiler. However, compared to conventional standard fuels such as heavy oil and light oil, there is a difference that alcohol easily volatilizes. Therefore, if this type of highly volatile liquid fuel is burned by a burner having a pair of nozzles as disclosed in Patent Document 1, there is a risk of inconvenience.

  Specifically, at the time of low combustion, the high combustion nozzle is in a stopped state without spraying the fuel. During that time, the high combustion nozzle receives heat from the combustion of the fuel from the low combustion nozzle, and the inside of the high combustion nozzle (from the solenoid valve). The fuel up to the nozzle tip may be volatilized. In addition, boilers are typically controlled at three positions, high combustion, low combustion, and shutdown, depending on the steam load. However, even during standby, the boiler receives heat from the previous combustion from the furnace. As a result, the fuel in each nozzle may volatilize. In these cases, the fuel spray from the nozzle is not smoothly performed, and there is a risk of misfire or misfiring due to disturbance in the air ratio.

  The problem to be solved by the present invention is to prevent misfire and misfire even when a highly volatile fuel such as alcohol is used.

The invention according to claim 1 includes a first nozzle and a second nozzle, and changes the amount of fuel spray from the second nozzle in a state where fuel spray from the first nozzle is continued. When starting fuel spraying from the first nozzle, the fuel supply valve to the second nozzle is opened and closed once or a plurality of times , and when starting fuel spraying from the second nozzle, only fuel spraying from the first nozzle just before is performed. The burner is characterized in that the presence / absence or number of times of opening / closing the fuel supply valve to the second nozzle or the opening time is changed based on the combustion time .

According to the invention described in claim 1, while continuing the fuel spray from the first nozzle, while varying the fuel spray amount from the second nozzle, when starting the fuel spray from the second nozzle, pre-second Open or close the fuel supply valve to the nozzle once or multiple times. Thereby, the cavity part by the fuel vaporization in a 2nd nozzle is filled, and reliable and stable combustion transfer can be implement | achieved. Note that “changing the amount of fuel spray from the second nozzle” includes changing the presence or absence of fuel spray from the second nozzle.

According to the invention described in claim 1, based on the time that has burned in only the fuel spray from the first nozzle, by changing the presence or number or opening time of pre-opening and closing the fuel supply valve to the second nozzle, The cavity part by the fuel vaporization in a 2nd nozzle can be filled appropriately.

The present invention as described in claim 2, when ignited by the fuel sprayed from the first nozzle, in claim 1, wherein the opening and closing advance the fuel supply valve to the first nozzle once or more times It is a burner of description.

According to the second aspect of the present invention, when the fuel is sprayed from the first nozzle and ignited, the fuel supply valve to the first nozzle is previously opened and closed once or a plurality of times, thereby vaporizing the fuel in the first nozzle. By filling the hollow portion, reliable and stable ignition can be realized.

  According to the present invention, even when a highly volatile fuel such as alcohol is used, misfire and misfire can be prevented.

BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic which shows an example of the boiler provided with the burner of one Example of this invention. It is the schematic which shows an example of the change of the combustion amount of the burner of FIG. 1, and the location which gave the hatching has shown the supply state of the fuel.

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic view showing an example of a boiler provided with a burner according to an embodiment of the present invention, with a part omitted and a part shown in cross section.

  The boiler 1 has a large number of water pipes 2, 2,... Arranged in a cylindrical shape, and a burner 4 is provided downward in the upper central portion of the cylindrical water pipe row 3 in the radial direction. The fuel discharged from the burner 4 is combusted inside the cylindrical water tube row 3. That is, the inside of the cylindrical water tube row 3 functions as the combustion chamber 5.

  The burner 4 of the present embodiment burns liquid fuel and includes two nozzles, a first nozzle 6 and a second nozzle 7. The first nozzle 6 includes a first nozzle pipe 8 and a first nozzle tip 9 provided at the tip of the first nozzle pipe 8. Moreover, the 2nd nozzle 7 is comprised from the 2nd nozzle pipe 10 and the 2nd nozzle tip 11 provided in the front-end | tip part.

  The first nozzle pipe 8 and the second nozzle pipe 10 are arranged with their axes extending in the vertical direction, and are provided adjacent to each other in parallel. At this time, the first nozzle chip 9 and the second nozzle chip 11 are adjacently provided at the same height in the illustrated example.

  The first nozzle 6 sprays the fuel supplied to the first nozzle pipe 8 downward from the first nozzle tip 9. The second nozzle 7 sprays the fuel supplied to the second nozzle pipe 10 downward from the second nozzle tip 11. In this embodiment, the spraying of fuel from the nozzle tips 9 and 11 is switched by opening and closing electromagnetic valves as fuel supply valves 12 and 13 to the nozzle pipes 8 and 10.

  Specifically, the fuel supply path 14 to both the nozzles 6 and 7 passes through the fuel pump 15 and the fuel main valve 16 and is then divided into two and connected to the nozzles 6 and 7. At that time, a first fuel supply valve 12 is provided in the fuel supply path to the first nozzle 6, and a second fuel supply valve 13 is provided in the fuel supply path to the second nozzle 7. Thereby, the fuel is supplied to the first nozzle 6 via the fuel pump 15, the fuel main valve 16, and the first fuel supply valve 12, and the fuel is supplied to the second nozzle 7, the fuel pump 15, the fuel original It is supplied via the valve 16 and the second fuel supply valve 13. The fuel source valve 16 is maintained in an open state when the boiler 1 is in operation.

  Accordingly, the fuel supply to the first nozzle 6 is performed by opening the first fuel supply valve 12 constituted by an electromagnetic valve while the fuel pump 15 is operated, and the fuel supply to the second nozzle 7 is performed. In the state where the fuel pump 15 is operated, the second fuel supply valve 13 constituted by an electromagnetic valve is opened. On the contrary, the fuel supply to the first nozzle 6 is stopped by closing the first fuel supply valve 12, and the fuel supply to the second nozzle 7 is stopped by closing the second fuel supply valve 13. Done. When the fuel supply to both the nozzles 6 and 7 is stopped, the operation of the fuel pump 15 may be stopped.

  In this way, in the present embodiment, the fuel spray from the first nozzle 6 is switched by the first fuel supply valve 12, and the fuel spray from the second nozzle 7 is switched by the second fuel supply valve 13. It is done. However, one or both of the nozzles 6 and 7 may change the flow rate as well as the presence or absence of fuel spray. For example, the flow rate of the fuel spray from the second nozzle 7 may be changed by providing a return path upstream from the fuel pump 15 in the middle of the second nozzle pipe 10 and adjusting the return amount. In that case, the combustion transition between the low combustion state and the high combustion state, which will be described later, can be performed more smoothly by adjusting the spray flow rate.

  In the burner 4 of this embodiment, the fuel supplied to the first nozzle 6 and the fuel supplied to the second nozzle 7 are the same. This fuel is a fuel having higher volatility than a conventional standard fuel such as heavy oil, light oil or kerosene, and is an alcohol such as ethanol.

  The burner 4 of this embodiment further includes a supply cylinder 17 that supplies combustion air into the combustion chamber 5. In the illustrated example, the supply cylinder 17 is composed of an inner and outer double cylinders arranged concentrically. The nozzle pipes 8 and 10 are provided along the axis of the supply cylinder 17. At this time, the nozzle pipes 8 and 10 are inserted and provided just before the lower opening of the supply cylinder 17.

  The burner 4 of this embodiment further includes a combustion cylinder 18 below the supply cylinder 17. In addition, a wind box 19 is provided at the upper portion of the supply cylinder 17, and air is supplied thereto from a blower (not shown). Air from the blower is supplied into the combustion chamber 5 as combustion air through the wind box 19 and the supply cylinder 17. When fuel is sprayed from the nozzles 6 and 7 for combustion, a desired amount of air is supplied into the combustion chamber 5 in this way.

  FIG. 2 is a schematic view showing an example of a change in the combustion amount of the burner 4 of the present embodiment, where the hatched portion shows the fuel supply state. In the figure, (a) shows the low combustion, (b) shows the transition, and (c) shows the high combustion. Moreover, in the same figure, among the pair of left and right nozzles 6 and 7 shown in each combustion stage, the left side shows the first nozzle 6 and the right side shows the second nozzle 7. Also, in the timing chart at the bottom of the figure, the lower part shows the presence or absence of fuel spray from the first nozzle 6 (specifically, the first fuel supply valve 12 is opened), and the upper part shows fuel spray from the second nozzle 7 ( Specifically, it indicates whether or not the second fuel supply valve 13 is open).

  In the present embodiment, the combustion amount of the boiler 1 is controlled at three positions of high combustion, low combustion, and stop. As is well known, the combustion amount can be controlled by monitoring the use load of steam based on the steam pressure from the boiler 1 and using a pressure switch (not shown).

  In this embodiment, fuel is sprayed from the first nozzle 6 during low combustion, as shown in FIG. 2 (a), and in addition to the first nozzle 6 during high combustion, as shown in FIG. 2 (c). Fuel is also sprayed from the second nozzle 7, and when stopped, fuel spray from both nozzles 6, 7 is stopped.

  As shown in FIG. 2 (b), when shifting from the low combustion state to the high combustion state, the fuel spray from the first nozzle 6 is continued and the second fuel supply valve 13 is turned once or a plurality of times in advance. Open and close. This is referred to as a pre-open / close operation. Since the second nozzle 7 is stopped at the time of low combustion, the fuel in the second nozzle 7 may be vaporized, but when the fuel spray from the second nozzle 7 is started, a prior opening / closing operation is performed. Thus, the cavity of the fuel in the second nozzle 7 can be filled. Thereafter, fuel spraying is continued from the second nozzle 7 again, and by changing the flow rate of the combustion air at this time, the combustion can be shifted while maintaining the air ratio as desired. However, if desired, the flow rate of the combustion air may start to increase at the stage of the preliminary opening / closing operation if desired, such as when the blower is inverter-controlled.

  By the way, when the fuel spray is started from the second nozzle 7, the second fuel supply valve 13 in the pre-opening / closing operation is based on the time when the fuel is burned only by the fuel spray from the first nozzle 6 just before (low combustion time immediately before). It is preferable to change the opening / closing time or number or opening time. Thereby, the cavity part by the fuel vaporization in the 2nd nozzle 7 can be filled appropriately.

  Such a prior opening / closing operation may be performed not only at the time of combustion transition but also at the time of ignition. That is, even during ignition, the fuel in the first nozzle 6 may be vaporized during standby until then, so that the first fuel supply valve 12 is opened and closed once or a plurality of times in advance immediately before the actual ignition operation. May be. Thereby, even if the fuel in the first nozzle 6 is vaporized, the cavity can be filled with the fuel. At this time, in the same manner as described above, based on the combustion stop time until immediately before, whether or not the first fuel supply valve 12 is opened / closed in the prior opening / closing operation or the number of times or the opening time may be changed. Thereafter, fuel spray may be continued from the first nozzle 6 again.

  The burner 4 of the present invention is not limited to the configuration of the above embodiment and can be changed as appropriate. In particular, in the case of using a highly volatile fuel such as alcohol, when the fuel is sprayed and the fuel starts to burn, the fuel supply valve to the nozzle is previously opened and closed once or a plurality of times. Each of the nozzles 6 and 7 may change the flow rate of the spray when fuel spray is performed. Further, the type of fuel, the configuration and control of the boiler 1 and the burner 4 can be changed as appropriate. In addition, the fuel supply valves 12 and 13 may be electrically operated valves in addition to electromagnetic valves. In that case, the pre-opening / closing operation of the fuel supply valves 12 and 13 does not need to be performed between full opening and full closing, and may be performed up to a desired opening degree. Furthermore, the present invention can be similarly applied to burners other than the boiler 1.

  Furthermore, in the said Example, although a pair of nozzles 6 and 7 were provided and highly volatile fuel was supplied to both the nozzles 6 and 7, the number of nozzles can be changed suitably and the fuel which changes with cases May be supplied. Even when different fuels are supplied, the fuel supply valve may be opened and closed in advance when starting to spray highly volatile fuel.

  When supplying different fuels to the nozzles 6 and 7, typically, a conventional standard fuel and a highly volatile fuel such as alcohol are used. In this case, the standard fuel may be a liquid fuel such as heavy oil, light oil or kerosene, or a gaseous fuel such as city gas, natural gas or liquefied petroleum gas. In any case, when starting to spray highly volatile fuel, the fuel supply valve may be opened and closed in advance. In addition, when discharging gaseous fuel instead of liquid fuel, the structure of the nozzle is changed into the structure of conventionally well-known various gas burners.

1 boiler 4 burner 6 first nozzle 7 second nozzle 12 first fuel supply valve 13 second fuel supply valve

Claims (2)

A first nozzle and a second nozzle;
With the fuel spray from the first nozzle continued, the fuel spray amount from the second nozzle is changed,
When starting fuel spray from the second nozzle, the fuel supply valve to the second nozzle is opened and closed once or multiple times in advance.
When starting fuel spraying from the second nozzle, based on the time of combustion only by fuel spraying from the first nozzle just before, whether or not the fuel supply valve to the second nozzle is previously opened or closed, or the opening time A burner characterized by changing . The burner according to claim 1 , wherein when the fuel is sprayed from the first nozzle and ignited, the fuel supply valve to the first nozzle is opened and closed once or a plurality of times.

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