JP6102544B2 - Coal burning burner - Google Patents

Description

  The present invention relates to a coal burning burner for co-combustion of low volatile coal and high volatile coal.

  There is a coal-burning burner that pulverizes coal and uses pulverized coal as fuel, but in recent years, there has been a demand for the use of composite coal in which a plurality of coals having different properties are mixed due to the variety of fuels.

  For example, when combusting coal with a mixture of anthracite, semi-anthracite, or oil coke (hereinafter referred to as flame retardant coal) with low volatility and coal with high volatility (hereinafter referred to as combustible coal) as a fuel, first combustible Coal burns. When combustible coal burns, oxygen in the combustion air is consumed, sufficient oxygen is insufficient to burn the flame-retardant coal, combustion of the flame-retardant coal deteriorates, and the flame becomes unstable. Arise.

  Therefore, when composite coal is used as a fuel, there is a problem that the flame is not stable and a good combustion state cannot be obtained.

  Patent Document 1 discloses a burner device suitable for combustion of flame-retardant coal.

JP 2008-138901 A

  In view of such circumstances, the present invention provides a coal-burning burner that maintains a good flame even with composite coal and that can achieve good combustion.

  The present invention relates to a throat provided in a furnace wall, a bottomed cylindrical burner chamber provided concentrically with the throat and opened at the core-side tip, and opened at an eccentric position at the bottom of the burner chamber. A pulverized fuel injection pipe for injecting a pulverized fuel flow that is a mixed flow of gas and primary air, an auxiliary air injection pipe for opening combustion concentric air that opens concentrically with the pulverized fuel injection pipe, and the burner chamber A tertiary air jet pipe that opens to a position eccentric to the opposite side of the fine fuel jet pipe with respect to the axis of the burner chamber at the bottom, and is formed between the burner chamber and the throat; The present invention relates to a coal burning burner including a ring-shaped ejection portion that ejects combustion secondary air.

  Further, the present invention relates to a coal burning burner in which the pulverized fuel ejection pipe and the auxiliary air ejection pipe have a double pipe structure, the pulverized fuel ejection pipe is an outer pipe, and the auxiliary air ejection pipe is an inner pipe. It is.

  Further, the present invention relates to a coal burning burner in which the pulverized fuel jet pipe and the auxiliary air jet pipe have a double pipe structure, the auxiliary air jet pipe is an outer pipe, and the pulverized fuel jet pipe is an inner pipe. It is.

  Furthermore, in the present invention, a second auxiliary air supply port is provided in the burner chamber, and a part of the combustion secondary air is supplied from the second auxiliary air supply port to the burner chamber. It is concerned.

  According to the present invention, a throat provided on the furnace wall, a bottomed cylindrical burner chamber provided concentrically with the throat and opened at the core side tip, and opened at an eccentric position at the bottom of the burner chamber, A pulverized fuel ejection pipe for ejecting a pulverized fuel stream that is a mixed flow of pulverized fuel and primary air; an auxiliary air ejection pipe that is opened concentrically with the pulverized fuel ejection pipe and ejects auxiliary combustion air; and the burner Formed between the burner chamber and the throat, at the bottom of the chamber is a tertiary air jet pipe which opens at a position eccentric to the opposite side of the fine fuel jet pipe with respect to the axial center of the burner chamber and jets tertiary air. In addition, since it has a ring-like jetting part that jets the secondary air for combustion, a good flame is maintained even with composite coal, and an excellent effect is obtained that good combustion is obtained.

It is a schematic sectional drawing of the coal burning burner which concerns on 1st Example of this invention. It is a schematic sectional drawing of the coal burning burner which concerns on the 2nd Example of this invention. (A) is explanatory drawing which shows the example of a change of 1st Example, (B) is explanatory drawing which shows the example of a change of 2nd Example.

  Embodiments of the present invention will be described below with reference to the drawings.

  The required number of burners 1 according to this embodiment are provided on the furnace wall 3 of the furnace 2.

  The furnace wall 3 is provided with a throat 4, and the burner 1 is provided concentrically with the throat 4. Hereinafter, the burner 1 will be described.

  A bottomed cylindrical burner chamber 6 having an open core end (hereinafter referred to as a front end) and a base end closed by a bottom plate 5 is provided concentrically with the throat 4. Between the throat 4 and the burner chamber 6, a ring-shaped combustion air outlet 7 is formed.

  An air register 8 is provided so as to surround the burner chamber 6. The air register 8 has a disk shape concentric with the burner chamber 6 and has an outer periphery opened. A wind box 9 is provided so as to accommodate the air register 8, and a secondary air blowing duct 11 communicates with the wind box 9, and combustion air is supplied to the wind box 9 through the secondary air blowing duct 11. The secondary air 12 is supplied.

  On the outer periphery of the air register 8, variable swirl vanes 13 are rotatably provided at a required pitch along the circumference, and the variable swirl vanes 13 are connected to each other by a link (not shown). The angle of the swirl vane 13 is changed synchronously. The secondary air 12 supplied to the wind box 9 flows into the air register 8 through the variable swirl vane 13 and is ejected into the furnace from the combustion air jet 7. Further, the secondary air 12 is swirled in the process of passing through the variable swirl vane 13, and the swirl force is adjusted by the angle of the variable swirl vane 13.

  A pulverized fuel injection pipe 15 is connected to the bottom plate 5, the downstream end (tip) of the pulverized fuel injection pipe 15 opens into the burner chamber 6, and the upstream end of the pulverized fuel injection pipe 15 is not shown in FIG. Connected to a fuel supply source, for example, a pulverized coal mill, the pulverized fuel is conveyed from the pulverized fuel supply source as a pulverized fuel stream 21 that is a mixed flow of pulverized fuel and primary air using primary air as a carrier medium. . The pulverized fuel is a mixture of flame retardant coal powder and combustible coal powder, and the primary air also functions as part of combustion air.

  An auxiliary air ejection pipe 16 is disposed inside the pulverized fuel ejection pipe 15 and concentrically with the pulverized fuel ejection pipe 15, and the tip of the auxiliary air ejection pipe 16 opens into the burner chamber 6. The pulverized fuel ejection pipe 15 and the auxiliary air ejection pipe 16 have a double pipe structure. In this embodiment, the pulverized fuel ejection pipe 15 is an outer pipe and the auxiliary air ejection pipe 16 is an inner pipe. ing.

  The auxiliary air ejection pipe 16 is connected to an auxiliary air supply source (not shown), and the auxiliary air ejection pipe 16 is provided with a flow rate adjusting valve 17. A pulverized fuel flow 21 adjusted in flow rate by the flow rate adjusting valve 17 is ejected from the bottom plate 5, and combustion auxiliary air 24 is ejected from the auxiliary air ejection pipe 16 to the center of the pulverized fuel flow 21. .

  A tertiary air ejection pipe 18 is connected to the bottom plate 5 and to a tertiary air supply source (not shown). The tertiary air ejection pipe 18 is provided with a flow rate adjusting valve 19. The tertiary air 20 is ejected from the tertiary air ejection pipe 18 into the burner chamber 6 and the flow rate ejected by the flow rate regulating valve 19 is increased. Adjusted.

  The pulverized fuel injection pipe 15 opens at a position eccentric from the center of the bottom plate 5. For example, as shown in the figure, the bottom plate 5 opens at a position eccentrically downward from the center of the bottom plate 5, and the tertiary air ejection pipe 18 is located on the opposite side of the pulverized fuel ejection pipe 15 with respect to the center of the bottom plate 5. It is opened at a position eccentrically upward from the center.

  Hereinafter, the operation of the burner 1 will be described.

  The pulverized fuel flow 21 is ejected from the pulverized fuel ejection pipe 15, and at the same time, the secondary air 12 passing through the air register 8 is ejected from the throat 4 as a swirling flow.

  The pulverized fuel flow 21 is ejected into the burner chamber 6 from a position deviated downward from the center of the burner chamber 6 and flows under the burner chamber 6. For this reason, a negative pressure region is formed above the pulverized fuel flow 21 in the burner chamber 6, and high-temperature exhaust gas in the furnace is drawn into the burner chamber 6, and between the burner chamber 6 and the furnace 2. Thus, a circulating flow 22 is formed.

  Due to the circulating flow 22, the inside of the burner chamber 6 becomes hot, and the fine fuel flow 21 ejected into the burner chamber 6 is ignited to form a flame 23.

  The tertiary air 20 adjusted to a required flow rate by the flow rate adjusting valve 19 is ejected from the tertiary air ejection pipe 18 into the burner chamber 6. Since the tertiary air 20 becomes a counterflow of the circulation flow 22, the formation of the circulation flow 22 is hindered. Therefore, the formation state of the circulating flow 22 is controlled by adjusting the flow rate of the tertiary air 20. Therefore, the amount of exhaust gas in the furnace that is drawn into the burner chamber 6 is controlled, and the temperature inside the burner chamber 6 is controlled.

The pulverized fuel stream 21 is heated and ignited by the circulating stream 22, but when heated by the circulating stream 22, first, volatile matter is emitted from the combustible coal, and the combustible coal burns.
As the combustible coal burns, oxygen in the flame is consumed.

  Since the secondary air 12 is supplied from the outside of the flame 23, it is not sufficiently supplied into the flame. For this reason, the combustion of the flame-retardant coal is in a state where oxygen is insufficient, and a good flame cannot be maintained.

  Next, according to the state of the flame 23, the auxiliary air 24 is supplied from the inside of the pulverized fuel flow 21 through the auxiliary air ejection pipe 16. Since the auxiliary air 24 is supplied to the inside of the flame, oxygen necessary for the combustion of the flame-retardant coal is supplied, and a good flame is maintained.

  Here, as an example of the mass ratio of primary air, secondary air, tertiary air, and auxiliary air, (primary air: secondary air: tertiary air: auxiliary air) is (2-3: 6) .5 to 4.5: 0.5: 1 to 2).

  Thus, according to the present embodiment, it is possible to realize good combustion with a composite fuel obtained by mixing fuels having different properties such as combustible coal and incombustible coal.

  Next, FIG. 2 shows a second embodiment. In FIG. 2, the same components as those shown in FIG.

  The relationship between the pulverized fuel jet pipe 15 for supplying the pulverized fuel flow 21 to the burner chamber 6 and the auxiliary air jet pipe 16 for supplying the auxiliary air 24 is changed. The auxiliary air jet pipe 16 is an outer pipe, The pulverized fuel ejection pipe 15 is an inner pipe, and the pulverized fuel ejection pipe 15 and the auxiliary air ejection pipe 16 are disposed concentrically.

  When the pulverized fuel flow 21 is ejected from the pulverized fuel ejection pipe 15 and the auxiliary air 24 is ejected from the auxiliary air ejection pipe 16, the auxiliary air 24 is ejected so as to wrap around the pulverized fuel stream 21. The pulverized fuel stream 21 and the auxiliary air 24 are easily mixed.

  Therefore, the auxiliary air 24 is supplied into the burner chamber 6 in addition to the primary air that is a carrier medium for the pulverized fuel. Therefore, even if combustible coal is first ignited and burned inside the burner chamber 6 and oxygen is consumed, oxygen is replenished by the supply of the auxiliary air 24, and oxygen shortage when incombustible coal burns is eliminated. The

  Further, by adjusting the supply amount of the auxiliary air 24 according to the state of the flame, an optimum combustion state with the composite fuel can be obtained, and therefore, by combining various combustible coals and non-combustible coals having different properties. A combination of composite fuels can be realized.

  FIGS. 3A and 3B show a modification of the first embodiment and the second embodiment.

  In a modified example of the first embodiment shown in FIG. 3A, the second auxiliary air supply port 25 is bored in the burner chamber 6 in a predetermined range with a predetermined distribution, and the inside of the burner chamber 6 is changed. And the air register 8 are communicated with each other via the second auxiliary air supply port 25. It should be noted that the range in which the second auxiliary air supply port 25 is provided is a predetermined range in the lower half of the burner chamber 6 as shown in the drawing, considering the influence on the pulverized fuel flow 21, the auxiliary air 24, and the tertiary air 20. It is preferable to be in the range.

  By providing the second auxiliary air supply port 25, a part of the secondary air 12 of the air register 8 is supplied into the burner chamber 6 as second auxiliary air.

  The diameter of the second auxiliary air supply port 25 is such that when the second auxiliary air flows into the burner chamber 6 from the second auxiliary air supply port 25, the flow rates are the fine fuel flow 21 and the auxiliary air 24. The third air 20 is set so as not to affect the flow of the tertiary air 20. In addition, the distribution, range, and opening ratio of the second auxiliary air supply port 25 are set based on experiments and the like, taking into account the properties of flame retardant coal, combustible coal provided as fuel, and the mixing ratio.

  By supplying the second auxiliary air from the second auxiliary air supply port 25 into the burner chamber 6, the shortage of oxygen when the flame-retardant coal burns is further compensated for, and the flame-retardant coal is improved. Contributes to burning.

  The modified example of the second example shown in FIG. 3B is also a modified example of the first example by supplying the second auxiliary air into the burner chamber 6 from the second auxiliary air supply port 25. Similarly, the combustion state of the flame retardant coal is improved.

DESCRIPTION OF SYMBOLS 1 Burner 2 Furnace 3 Furnace wall 4 Throat 6 Burner chamber 7 Combustion air outlet (spout part)
DESCRIPTION OF SYMBOLS 8 Air register 12 Secondary air 15 Fine powder fuel injection pipe 16 Auxiliary air injection pipe 17 Flow rate adjustment valve 18 Tertiary air injection pipe 19 Flow rate adjustment valve 20 Tertiary air 21 Fine powder fuel flow 22 Circulation flow 24 Auxiliary air 25 Second auxiliary air Supply port

Claims (4)

  A throat provided in the furnace wall, a bottomed cylindrical burner chamber concentrically provided with the throat and opened at the core side tip, and opened at an eccentric position at the bottom of the burner chamber, and pulverized fuel and primary air A pulverized fuel jet pipe for jetting a pulverized fuel flow which is a mixed flow with the pulverized fuel, an auxiliary air jet pipe which opens concentrically with the pulverized fuel jet pipe and jets auxiliary combustion air, and the burner at the bottom of the burner chamber A secondary air jet pipe which is formed between the burner chamber and the throat, and is formed between the burner chamber and the throat, which is opened at a position eccentric to the opposite side of the fine powder fuel jet pipe with respect to the axial center of the chamber. A coal-fired burner comprising a ring-shaped jetting part for jetting air.   2. The coal burning burner according to claim 1, wherein the pulverized fuel ejection pipe and the auxiliary air ejection pipe have a double pipe structure, the pulverized fuel ejection pipe is an outer pipe, and the auxiliary air ejection pipe is an inner pipe.   2. The coal burning burner according to claim 1, wherein the pulverized fuel ejection pipe and the auxiliary air ejection pipe have a double pipe structure, the auxiliary air ejection pipe is an outer pipe, and the pulverized fuel ejection pipe is an inner pipe.   The second auxiliary air supply port is provided in the burner chamber, and a part of the combustion secondary air is supplied into the burner chamber from the second auxiliary air supply port. The coal burning burner according to 1.

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