JP7485937B2 - Coke Oven Drying Burner - Google Patents

Description

The present invention relates to a coke oven drying burner used during lighting in a coke oven furnace body facility.

Conventionally, coke ovens that produce coke by high-temperature carbonization of coal loaded into a carbonization chamber have been provided with a structure in which multiple carbonization chambers and combustion chambers are arranged alternately above a heat regenerator. In these coke ovens, fuel gas and air are supplied from the heat regenerator to the combustion chamber for combustion, and coal is loaded into the carbonization chamber located adjacent to the combustion chamber, and the coal is carbonized at high temperature to produce coke.

The furnace body of such a coke oven is constructed with firebricks, and after construction, the furnace body is wet due to the moisture contained in the firebricks themselves and the joint mortar. For this reason, the furnace body needs to be thoroughly dried before it is lit to start actual operation. Drying of the furnace body after construction is also carried out for furnaces other than coke ovens, but since the furnace body of a coke oven in particular has a furnace structure divided into multiple furnace chambers, including the heat storage chamber, combustion chamber, and carbonization chamber, the furnace body is generally dried by burning fuel such as COG or diesel in the carbonization chamber, and directing the combustion exhaust gas to the entire furnace body, including the combustion chamber, bellows, heat storage chamber, and horizontal flue, and finally discharging the combustion gas into the atmosphere through the flue and chimney.

As a method for drying the furnace body in this way, for example, a method for drying a coke oven using a burner installed on the furnace roof is known.
Here, silica bricks are generally used as furnace materials for coke ovens, and there is a risk of cracks occurring due to volume changes accompanying phase transitions during drying and heating after construction. To avoid this, it is necessary to slow down the heating rate, which is extremely slow in the temperature range of 250°C or less at the beginning of drying, and then the heating rate is gradually increased until the brick temperature reaches 800°C.

However, when a burner is installed in the carbonization chamber and the furnace body is dried by the combustion exhaust gas, the burner is installed near the entrance of the carbonization chamber and the combustion flame extends in the depth direction of the carbonization chamber, so that the temperature deviation of the combustion flame occurs in the depth direction of the carbonization chamber. Therefore, in order to suppress the occurrence of cracks in the silica bricks that make up the furnace wall of the carbonization chamber, it was necessary to monitor and raise the temperature of the furnace wall position of the carbonization chamber, which becomes the hottest due to the combustion flame. For this reason, it was necessary to further slow down the rate at which the furnace body is heated by the burner, which caused a problem of a very long drying period.
Therefore, in order to suppress the temperature deviation inside the carbonization chamber caused by the burner combustion flame, it is possible to shorten the burner combustion flame so that the burner combustion flame does not directly heat the furnace walls of the carbonization chamber, and to heat the carbonization chamber using the sensible heat of the combustion exhaust gas.

As described above, when drying the body of a coke oven, in order to suppress the occurrence of cracks due to volume changes accompanying the phase transition of silica bricks, the heating rate is extremely slow in the temperature range of 250°C or less in the early stages of drying, and then the heating rate is gradually increased until the brick temperature reaches 800°C. For this reason, the amount of fuel supplied is extremely small in the early stages of drying, and the air ratio increases accordingly. On the other hand, in the latter stages of drying, the amount of fuel supplied increases and the air ratio decreases. Specifically, when COG is used as fuel, the amount of fuel supplied changes by about 50 times between the early stage and the latter stages of drying, and the air ratio also changes by about 30 times. However, conventional short-flame burners could not accommodate such a wide range of combustion loads. Thus, conventionally, there was no short-flame burner suitable for drying coke oven bodies, and it took a long time to dry coke oven bodies.

In response to this, for example, Patent Document 1 proposes a furnace drying method in which a burner is installed in the carbonization chamber, the tip face of which is closed and multiple small holes are provided in the side wall at the tip side, and the ratio D/d of the outer diameter d of the inner tube to the inner diameter D of the outer tube is set to 2.5 or more. This suppresses the occurrence of temperature deviation in the depth direction of the carbonization chamber even when a burner is installed in the carbonization chamber for heating and drying, and by appropriately adjusting the temperature rise rate, it is possible to shorten the drying period.

JP 2017-171901 A

However, in the case of coke oven drying burners used to dry the furnace body when lighting the coke oven furnace equipment, there was a risk that the flame caused by the fuel ejected from the gas hole would go out when the gas flow rate was low and the fuel supply rate was small. For this reason, there was a demand for a burner that could improve flame holding performance and more reliably prevent misfires, and there was room for improvement in this regard.

The present invention was made in consideration of the above-mentioned problems, and aims to provide a coke oven drying burner that can suppress misfires even at low gas flow rates and improve flame holding performance.

In order to achieve the above object, the coke oven drying burner of the present invention is a coke oven drying burner used for drying the furnace body at the time of lighting in a coke oven furnace body facility having a structure in which a combustion chamber and a carbonization chamber are alternately arranged above a heat storage chamber, and is characterized in that it has a double-tube structure with an inner tube to which fuel is supplied and an outer tube to which air is naturally supplied, the tip face of the inner tube is closed and a plurality of gas holes are provided in the tip side wall in a plurality of rows along the tube axis direction, and the distance Y from the nozzle tip side of the inner tube to the hole center of the first row of the gas holes satisfies formula (1) when the hole diameter of the gas holes is d1.

In the present invention, the distance Y from the nozzle tip side to the center of the first row of gas holes is set to satisfy formula (1), so that a gas reservoir where fuel gas accumulates can be generated in the area in front of the nozzle tip of the inner tube, and the low-velocity area where the flow velocity of the air flowing in the outer tube is suppressed can be expanded, improving the flame stabilization effect. This makes it possible to prevent the flame caused by the fuel ejected from the gas holes from going out even when the amount of fuel gas supplied is low.
In addition, since the tip end face of the inner tube is closed and a plurality of gas holes are provided in the side wall on the tip side, the burner flame can be made shorter.

Therefore, since combustion is stable even over a wide range of combustion loads, drying can be performed stably over the entire range from the early stage to the latter stage of drying.
In addition, because the burner flame is short, the burner is prevented from directly heating the furnace wall of the carbonization chamber, and the furnace wall of the carbonization chamber can be heated and dried by the sensible heat of the combustion exhaust gas from the burner, and the occurrence of temperature deviation in the depth direction of the carbonization chamber can be suppressed. This allows the temperature rise rate to be managed according to the appropriate temperature of the entire carbonization chamber, and the drying period of the furnace body when burning can be shortened. In addition, because there are no locally high temperature areas, the occurrence of cracks in the firebricks that make up the furnace wall of the carbonization chamber can be suppressed.

The coke oven drying burner according to the present invention may also be characterized in that the radius of curvature R of the outer peripheral edge of the nozzle tip of the inner tube is 5 mm or more.

In this case, by making the radius of curvature of the outer periphery of the nozzle tip of the inner tube 5 mm or more, the fuel gas can easily flow toward the front of the nozzle tip. This can further improve the flame holding effect, and more reliably prevent misfires when the fuel gas supply is low and at low flow rates.

In addition, it is preferable that the coke oven drying burner according to the present invention is characterized in that when the gas hole diameter of the first row of gas holes in the inner tube is d1 and the gas hole diameter of the second row and thereafter is d2, formula (2) is satisfied.

According to the present invention, the relationship between the gas hole diameter d1 of the first row of gas holes and the gas hole diameter d2 of the second row and onwards is set to satisfy formula (2), so that the fuel gas can easily flow forward toward the nozzle tip, and a stable flame-holding effect can be obtained. Therefore, misfires can be more effectively suppressed when the fuel gas supply is low and the flow rate is low.

The coke oven drying burner according to the present invention may also be characterized in that the hole diameter ratio d1:d2 between the gas hole diameter d1 of the first row and the gas hole diameter d2 of the second row and thereafter is 5:3 to 7:3.

According to this configuration, by setting the hole diameter ratio d1:d2 between the gas hole diameter d1 in the first row and the gas hole diameter d2 in the second row and onwards to 5:3 to 7:3, a gas pool can be generated at the nozzle tip, providing a high flame-holding effect and improving the turndown ratio while maintaining a short flame (non-luminous flame). Therefore, by making the gas holes in the first row larger in diameter, pressure loss can be reduced, and continuous operation is possible regardless of the fuel gas supply amount, from low to high flow rates, without the need to replace the nozzle tip (tip of the inner tube) according to the gas amount as was previously done, which shortens the construction period.

The coke oven drying burner according to the present invention may also be characterized in that the outer tube is provided with a plurality of air intakes spaced apart in the circumferential direction, the air intakes being formed as long holes extending along the axial direction of the outer tube, the outer tube is provided with an opening and closing tube that is coaxial with the outer tube and slidable in the axial direction, and the opening and closing tube is positioned at any position between a fully closed position and a fully open position relative to the air intakes.

According to this configuration, the opening and closing cylinder slides in the tube axial direction relative to the multiple air intakes arranged at intervals in the circumferential direction of the outer tube, thereby adjusting the opening amount of the air intakes. In this case, regardless of the sliding position of the opening and closing cylinder, the multiple air intakes can be accurately adjusted to the same opening amount.
This reduces the variation in the amount of air drawn into the outer tube from each air intake. Therefore, the air ratio of multiple burners in the drying process can be controlled to reduce the variation. In this case, the open/close cylinder is simply slid along the outer tube in the tube axis direction.

The coke oven drying burner according to the present invention may also be characterized by being provided with a positioning means for positioning the opening and closing tube.

With this configuration, the positioning means can position the slide position of the opening and closing tube at any position with high precision, and the opening size of the air intake can be easily adjusted with a simple structure.

In addition, in the coke oven drying burner of the present invention, it is preferable that the relationship between the outer diameter dimension D of the outer tube and the length dimension T from the tip of the outer tube to the outer surface of the coke chamber in the axial direction of the outer tube satisfies equation (3).

With this configuration, the relationship between the outer diameter dimension D and the length dimension T of the outer tube is set to satisfy formula (3), so the noise generated in the coke oven during drying can be kept low. This makes it possible to set the length dimension T of the outer tube long, preventing flames from entering the coke oven.

The coke oven drying burner of the present invention can suppress misfires even at low gas flow rates, improving flame stability.

1 is a schematic explanatory diagram of a coke oven to which a method for drying a furnace body at the time of firing in a coke oven furnace body facility according to an embodiment of the present invention is applied. FIG. FIG. 2 is a cross-sectional view of the coke oven shown in FIG. 1 . FIG. 4 is a cross-sectional explanatory diagram of the carbonization chamber during drying of the furnace body. 1 is a cross-sectional explanatory view of a burner according to an embodiment of the present invention; 5 is an enlarged view of a main portion of a tip portion of the inner tube shown in FIG. 4 . FIG. 4 is a half cross-sectional view showing the configuration of the opening and closing cylinder as viewed from the side. 6A and 6B are diagrams illustrating analysis results of the first embodiment. 13A and 13B are graphs showing analysis results of the second embodiment. 13A, 13B, and 13C are diagrams showing the arrangement of gas holes in an inner tube of a third embodiment. 13 is a graph showing an analysis result of the third embodiment. 13A and 13B are diagrams showing analysis results of the fourth embodiment. 13A and 13B are diagrams showing analysis results of the fourth embodiment. FIG. 13 is a diagram showing the standard deviation of the temperature near the furnace wall for each blower suction pressure according to the embodiment.

Below, a coke oven drying burner according to an embodiment of the present invention will be described with reference to the drawings.

As shown in FIG. 1, the coke oven drying burner of this embodiment (burner 40 shown in FIG. 3 and FIG. 4) is used to dry the furnace body at the time of lighting in a furnace body facility of a coke oven 1 having a structure in which combustion chambers and carbonization chambers are arranged alternately above the heat storage chamber.

As shown in FIG. 1 , the coke oven 1 of this embodiment has a plurality of coke chambers 10 arranged in parallel, and a combustion chamber 20 is disposed between two adjacent coke chambers 10 .
As shown in FIG. 2, a heat storage chamber 30 is disposed below the carbonization chamber 10 and the combustion chamber 20 which are arranged in parallel.

As shown in Figures 1 and 2, multiple loading ports 12 for loading coal are formed on the upper surface of the coking chamber 10, and an uprising pipe 14 for discharging exhaust gas generated from the coking chamber 10 is arranged at the end of the coking chamber 10, and this uprising pipe 14 is connected to the drymen 3.
In addition, in order to efficiently transfer heat from the combustion chamber 20 provided between the parallel carbonization chambers 10 to the coal, the distance between a pair of furnace walls (furnace walls located on the combustion chamber 20 side) of the carbonization chamber 10 is made relatively short. That is, the furnace width of the carbonization chamber 10 is made narrow.

1 and 2, an inspection hole 21 for inspecting the inside of the combustion chamber 20 and a thermometer 22 are provided on the upper surface of the combustion chamber 20. In addition, a partition wall 24 is provided in the combustion chamber 20, as shown in FIG.
The heat storage chamber 30 is configured to introduce combustion gas and air into the combustion chamber 20 and to discharge exhaust gas from the combustion chamber 20, and is connected to a supply pipe 5 for combustion gas and air and a flue 7 as shown in FIG. 2.

Here, the furnace body equipment of the coke oven 1, which includes the carbonization chamber 10, the combustion chamber 20 and the heat storage chamber 30, is constructed by stacking silica bricks, and since the silica bricks and joint mortar, etc. contain moisture when the oven is constructed, the furnace body equipment needs to be dried before ignition to start actual operation.
Drying of the furnace body equipment of the coke oven 1 is carried out by inserting a burner 40 through the furnace cover of the carbonization chamber 10, as shown in Figure 3, and introducing the combustion exhaust gas from this burner 40 from the carbonization chamber 10 into the entire furnace body equipment including the combustion chamber 20 and the heat regenerator chamber 30.

Next, the structure of the burner 40 in this embodiment will be described in detail with reference to FIG.
The burner 40 has a double-pipe structure including an inner pipe 41 to which the fuel E is supplied and an outer pipe 42 to which the primary air A1 is naturally supplied. In this embodiment, a secondary air flow path 49 to which the secondary air A2 is introduced is formed between the outer pipe 42 and the burner tile 48.
In the following description, the tip side of the inner tube 41 and the outer tube 42 in the direction of the tube axis O is referred to as the front side, and the opposite side is referred to as the rear side.

The tip surface of the inner tube 41 is closed by a nozzle tip portion 41a, and a plurality of gas holes 43 (43A, 43B) are arranged in a plurality of rows (two rows in this embodiment) on the side wall on the tip side along the tube axis O. The gas hole diameter of the gas holes 43 is within a range of 3 mm or more and 8 mm or less, and the number of the gas holes 43 is within a range of 10 to 30.
In this embodiment, the first row of gas holes 43A and the second row of gas holes 43B near the nozzle tip portion 41a are provided in a staggered arrangement in the circumferential direction as shown in Fig. 5. The region in which these gas holes 43A and 43B are formed is within a range of 100 mm to 300 mm rearward from the nozzle tip portion 41a of the inner tube 41.

The gas holes 43 are set to satisfy formula (1) at a distance Y from the nozzle tip 41a to the center C of the first row of gas holes 43A, where the hole diameter of the first row of gas holes 43A is d1.

As shown in FIG. 5, the radius of curvature R of an outer circumferential edge portion 41d at the nozzle tip portion 41a of the inner tube 41 is 5 mm or more.
In addition, when the gas hole diameter of the gas holes 43A in the first row in the inner tube 41 is d1 and the gas hole diameter of the gas holes 43B in the second row and thereafter is d2, the gas hole diameter is set so as to satisfy (2).

The hole diameter ratio d1:d2 between the gas hole diameter d1 of the first row in the inner tube 41 and the gas hole diameter d2 of the second row and onwards is set to 5:3 to 7:3.

In this embodiment, SUS304 stainless steel, which is resistant to high-temperature oxidation, is used as the material for the inner tube 41. In this embodiment, by using SUS304, iron oxide is prevented from being generated on the inner surface of the inner tube 41, and clogging of the gas holes 43 can be suppressed.
In this case, by using SUS304 for the inner tube 41 in which the gas holes 43 are formed, even if the temperature around the inner tube 41 exceeds 800°C, it is possible to prevent blockage caused by iron oxide being generated on the inner surface of the nozzle due to high-temperature oxidation and adhering to the vicinity of the gas holes 43.

As shown in FIG. 4, the outer tube 42 has a tube body 42A and an air introduction tube portion 42B provided on the rear end side (base end portion 42c side) of the tube body 42A. The air introduction tube portion 42B has a plurality of air intake ports 44 formed at regular intervals in the circumferential direction, and is structured so that primary air A1 is naturally supplied into the outer tube 42. A primary air flow path 42C is formed between the outer peripheral surface 41b of the inner tube 41 and the inner peripheral surface 42a of the outer tube 42.

As shown in FIG. 6, the air intakes 44 are disposed in a region forward of the center of the air introduction tube portion 42B in the tube axis O direction. The air intakes 44 are formed as long holes extending along the tube axis O direction of the outer tube 42, and multiple air intakes 44 have the same shape. The outer tube 42 is configured such that the multiple air intakes 44 are arranged at regular intervals in the circumferential direction, so that primary air A1 is supplied uniformly into the outer tube 42 in the circumferential direction.

As shown in FIG. 4, the tube body 42A of the outer tube 42 is set so that the relationship between the outer diameter dimension D and the length dimension T in the tube axis O direction (the distance from the outer tube tip 42b to the outer surface 10a of the coking chamber 10) satisfies formula (3).

As shown in FIG. 4, the nozzle tip 41a of the inner tube 41 is positioned at a position set back from the outer tube tip 42b of the outer tube 42. The setback distance is set within a range of, for example, 150 mm to 600 mm.

As shown in FIG. 6, the outer tube 42 is provided with an opening/closing tube 45 that is coaxial with the outer tube 42 and can slide in the tube axis O direction relative to the air introduction tube portion 42B. The opening/closing tube 45 is configured to be positionable at any position between a closed position that fully closes the multiple air intake ports 44 and a fully open position that fully opens them. In the closed position, the opening/closing tube 45 is positioned so as to cover the outer periphery of the air introduction tube portion 42B, and in the fully open position, the opening/closing tube 45 is positioned so as to retreat to the rear of the air introduction tube portion 42B.

A belt-shaped guide 46 extending along the tube axis O is provided on the outer circumferential surface 42e of the air inlet tube portion 42B. The guide 46 is formed with a slit 46A extending in the length direction, and a slide piece 45A provided on the opening and closing tube 45 is supported slidably along the slit 46A.
The guide 46 is provided with a scale plate 46B (positioning means) having graduations in the direction of the tube axis O. This allows the opening and closing cylinder 45 to be positioned at any desired position relative to the air inlet cylinder portion 42B by aligning it with the graduations on the scale plate 46B.

As shown in Figures 1 and 2, when drying the furnace body equipment of the coke oven 1, fuel E such as COG or light oil is burned using a burner 40 shown in Figure 4, and the sensible heat of the combustion exhaust gas from the burner 40 is used to heat and dry the furnace wall of the carbonization chamber 10, and this combustion exhaust gas is discharged into the carbonization chamber 10 and introduced into the entire furnace body equipment including the combustion chamber 20 and the heat storage chamber 30.
At this time, temperature control during drying involves monitoring the temperature of the hottest area of the furnace wall of the coking chamber 10 in order to suppress the occurrence of cracks caused by volume changes accompanying the phase transition of the silica bricks.

Next, the operation of the burner 40 will be described in detail with reference to the drawings.
In the burner 40 of this embodiment, as shown in Figures 4 and 5, the distance Y from the nozzle tip 41a to the hole center C of the first row of gas holes 43 is set to satisfy the above-mentioned formula (1), so that a gas reservoir in which gas remains can be generated in the forward region of the nozzle tip 41a of the inner tube 41, and the low-velocity region in which the flow velocity of the air flowing inside the outer tube 42 is suppressed is expanded, thereby improving the flame-stabilizing effect.
As a result, even when the supply amount of fuel E is low, it is possible to prevent the flame of the fuel E ejected from the gas hole 43 from going out.
In addition, since the tip end face of the inner tube 41 is closed and a plurality of gas holes 43 are provided in the side wall on the tip side, the flame of the burner 40 can be made short.

Therefore, since combustion is stable even over a wide range of combustion loads, drying can be performed stably over the entire range from the early stage to the latter stage of drying.
In addition, in this embodiment, the burner 40 is made to have a short flame, so that the burner 40 is prevented from directly heating the furnace wall of the carbonization chamber 10, and the furnace wall of the carbonization chamber 10 can be heated and dried by the sensible heat of the combustion exhaust gas of the burner 40, and the occurrence of temperature deviation in the depth direction of the carbonization chamber 10 can be suppressed. This allows the temperature rise rate to be managed according to the appropriate temperature of the entire carbonization chamber 10, and the drying period of the furnace body at the time of firing can be shortened. In addition, since there are no locally high-temperature parts, the occurrence of cracks in the firebricks that make up the furnace wall of the carbonization chamber 10 can be suppressed.

In addition, in this embodiment, the radius of curvature R of the outer peripheral edge 41d of the nozzle tip 41a of the inner tube 41 is set to 5 mm or more, which makes it easier for gas to flow toward the front of the nozzle tip 41a. This further improves the flame-holding effect, and more reliably prevents misfires when the supply of fuel E is low and at a low flow rate.

In addition, in this embodiment, the relationship between the gas hole diameter d1 of the first row of gas holes 43A and the gas hole diameter d2 of the second row and subsequent rows of gas holes 43B is set to satisfy the above-mentioned formula (2), so that gas can easily flow toward the front of the nozzle tip 41a, and a stable flame-holding effect can be obtained. Therefore, misfires can be more effectively suppressed when the fuel supply is low and the flow rate is low.

Furthermore, in this embodiment, the hole diameter ratio d1:d2 between the gas hole diameter d1 of the first row in the gas holes 43 and the gas hole diameter d2 of the second row and onwards is set to 5:3 to 7:3, which allows gas to accumulate at the nozzle tip 41a and provides a high flame-holding effect, thereby improving the turndown ratio while maintaining a short flame (non-luminous flame). Therefore, by making the gas holes 43A in the first row larger in diameter, pressure loss can be reduced, and the nozzle tip (the tip of the inner tube 41) does not need to be replaced according to the gas amount, as was previously required, regardless of the supply amount of fuel E, from low to high flow rates, making continuous operation possible, thereby shortening the construction period.

6, the opening and closing cylinder 45 slides in the direction of the tube axis O relative to the plurality of air intakes 44 arranged at intervals in the circumferential direction of the outer tube 42, thereby making it possible to adjust the opening amount of the air intakes 44. In this case, regardless of the sliding position of the opening and closing cylinder 45, each of the plurality of air intakes 44 can be accurately adjusted to the same opening amount.
This makes it possible to reduce the variation in the amount of the first air A1 sucked into the outer tube 42 from each air intake 44. Therefore, it is possible to control the air ratio of the multiple burners 40 in the drying process so as to reduce the variation. In this case, the open/close cylinder 45 has a simple structure in which it slides in the tube axis O direction along the outer tube 42.

In addition, in this embodiment, the scale plate 46B provided on the air inlet tube portion 42B of the outer tube 42 allows the sliding position of the opening and closing tube 45 to be positioned at any position with high precision, and the opening amount of the multiple air intakes 44 can be easily adjusted with a simple structure.

In addition, in this embodiment, as shown in FIG. 4, the relationship between the outer diameter dimension D and the length dimension T of the outer tube 42 is set to satisfy the above-mentioned formula (3), so that the noise of the coke oven generated during drying can be kept low. Therefore, it is possible to set the length dimension T of the outer tube 42 to be long, and it is possible to prevent the flame from entering the coke oven.

The coke oven drying burner according to the present embodiment described above can suppress misfires even at low gas flow rates, improving flame stability.

Next, we will explain examples that were conducted to verify the effectiveness of the coke oven drying burner according to the above-mentioned embodiment.

(First embodiment)
In the first embodiment, in order to confirm the flame stabilization effect when the position in the tube axial direction of the gas holes 43 provided in the inner tube 41 is changed, an FEM model was created and a numerical simulation analysis was performed to confirm the effect.

7(a) and (b) show the analysis results of Example 1. In the figures, gas flow velocity vectors are displayed inside and outside the inner tube 41.
The experimental case shown in Fig. 7(a) has eight gas holes 43 with a diameter of 3 mm spaced apart in the circumferential direction at the tip of the inner tube 41. The comparative case shown in Fig. 7(b) has eight gas holes 43 with a diameter of 3 mm spaced apart in the circumferential direction at a position rearward of the tip of the inner tube 41. The regions marked with symbols S1 and S2 in Figs. 7(a) and 7(b) respectively indicate stagnation regions (low-velocity regions) where the gas flow velocity is low.

In the results of the first embodiment, it was confirmed that the low velocity region formed in front of the nozzle tip 41a was expanded by arranging the gas holes 43 closer to the nozzle tip 41a. In other words, it was found that the flame stabilization effect was improved by expanding the low velocity region S1 of the working case more than the low velocity region S2 of the comparative case.
It was also confirmed that the flame stabilization effect is improved as the position of the gas hole 43 is closer to the nozzle tip 41a.

Second Example
In the second embodiment, in the FEM model used in the first embodiment described above, a numerical simulation analysis was performed on an implementation case in which the gas hole diameters of the two rows of gas holes were different for each row, and a comparison case in which the hole diameters were the same for each row, and the flame stabilization effect was confirmed.

The experimental case had an inner tube with eight gas holes with a hole diameter of 5 mm arranged in the first row and eight gas holes with a hole diameter of 3 mm arranged in the second row, while the comparative case had an inner tube with eight gas holes with a hole diameter of 3 mm arranged in the first and second rows.
In the simulation analysis, the misfire conditions were confirmed by changing the suction pressure (-mmAq) of the primary air port (air intake port) around 0.6 Nm ³ /h in the first row gas hole as a low COG flow condition that is prone to misfire.

Figures 8(a) and (b) show the results of the second embodiment. Figures 8(a) and (b) show the relationship between the COG amount ( ^Nm3 /h) and the primary air port suction pressure (-mmAq). The higher the primary air port suction pressure, the higher the air ratio. The solid line in the figure shows the boundary line of the misfire zone where misfires occur (misfire boundary line Q1), and the area where the suction pressure is higher than the misfire boundary line Q1 becomes the misfire zone. The dotted line in the figure shows the planned combustion conditions. The upper limit of the primary air port suction pressure is set to -4mmAq based on past performance.

As a result of the analysis of the second embodiment, it was confirmed that the extinguishing zone was smaller in the implementation case than in the comparison case, and that misfires were less likely to occur. This was confirmed by confirming that the flame-holding effect was improved by the lower pressure loss at the tip of the first row of gas holes and the increased flow rate at the tip.

(Third Example)
In the third embodiment, in the FEM model used in the first embodiment described above, numerical simulation analysis was performed on a practical case in which the gas hole diameters of the two rows of gas holes were different for each row, and on comparative cases 1 and 2 in which the hole diameters of the same row were used for each row, and an improvement in the turndown ratio was confirmed.

As shown in FIG. 9(c), Example Case 1 is a nozzle (inner tube) with eight gas holes with a hole diameter of 5 mm arranged in the first row and eight gas holes with a hole diameter of 3 mm arranged in the second row. As shown in FIG. 9(b), Comparative Case 1 is a nozzle with eight gas holes with a hole diameter of 3 mm arranged in a staggered manner in each of the first and second rows. As shown in FIG. 9(a), Comparative Case 2 is a nozzle with one gas hole with a hole diameter of 8 mm arranged near the nozzle tip. In addition to the above, in the third embodiment, a numerical simulation was also performed for Example Case 2. Example Case 2 is a nozzle with eight gas holes with a hole diameter of 7 mm arranged in the first row and eight gas holes with a hole diameter of 3 mm arranged in the second row.

In the numerical simulation analysis, the turndown ratio was compared and examined based on the relationship (Fig. 10) between the COG amount ( ^Nm3 /h) and the nozzle pressure loss (Pa) of the inner pipe. The nozzle back pressure limit (allowable pressure loss limit) for the nozzle pressure loss was set at 1300 Pa, and the nozzle was replaced when this back pressure limit was reached, and the replacement frequency was confirmed.
In Comparative Case 2, when the nozzle with a hole diameter of 8 mm reached the back pressure limit of 1,300 Pa, it was replaced with a nozzle with a hole diameter of 14 mm, and when the back pressure next reached the limit, it was replaced with a nozzle with a hole diameter of 25 mm.

Figure 10 shows the results of the third embodiment. The graph with reference symbol T11 in Figure 10 shows Example Case 1, and the graph with reference symbol T21 shows Comparative Case 1. The graphs with reference symbols T22, T23, and T24 show Comparative Case 2, where the nozzles have hole diameters of 8 mm, 14 mm, and 25 mm, respectively. The graph with reference symbol T12 shows Example Case 2.

As a result of the numerical simulation analysis according to the third embodiment, it was confirmed that a turndown ratio of 1:42 (COG amount of 0.6 to 25 ^Nm3 /h) could be achieved in Example Case 1. The number of times the nozzle was changed at this time was two times in Comparative Case 2, one time in Comparative Case 1, and zero times in Example Case 1.
By making the diameter of the gas holes in the first row larger in this way, it is possible to reduce pressure loss, making it possible to eliminate the need to replace nozzle tips in accordance with the amount of gas, as was previously done, and thus achieving the effect of shortening the construction period.

(Fourth Example)
Next, a fourth embodiment will be described.
In the fourth embodiment, in order to confirm the state of air taken in through a plurality of air intakes formed in the outer tube, an FEM model was created and a numerical simulation analysis was performed to confirm the effect.

In the numerical simulation analysis of the fourth embodiment, an implementation case was used in which the first opening and closing tube 451 that slides back and forth (slides in the tube axial direction) as shown in the above-mentioned embodiment as shown in Figure 11 (a) and a comparison case was used in which the second opening and closing tube 452 that rotates and slides in a circumferential direction relative to the outer tube 42 as shown in Figure 11 (b), and the distribution of temperature and air flow velocity was analyzed to confirm the variation in the air supply amount.
The symbol 44A in Figure 11 (a) indicates an air intake whose opening degree is adjusted by a first opening and closing cylinder 451, and the symbol 44B in Figure 11 (b) indicates an air intake whose opening degree is adjusted by a second opening and closing cylinder 452.

11A and 11B are the results of a numerical simulation analysis, and show the temperature distribution in the vicinity of the tip (nozzle tip 41a) of the inner tube 41 in the burner.
As a result, it was confirmed that the temperature in the vicinity of the gas hole (reference symbol K1 in the figure) in the first opening and closing cylinder 451 of the front and rear slide of the embodiment case shown in Fig. 11(a) was higher than the temperature in the vicinity of the gas hole (reference symbol K2 in the figure) in the second opening and closing cylinder 452 of the rotating slide of the comparison case shown in Fig. 11(b). On the other hand, it was confirmed that the temperature in the area (reference symbols K3 and K4) forward of the nozzle tip portion 41a was higher in the second opening and closing cylinder 452 than in the first opening and closing cylinder 451.

12(a) and 12(b) show the results of a numerical simulation analysis, which show the distribution of vectors indicating the air flow near the tip of the inner tube 41 (nozzle tip 41a) in the burner. Fig. 12(a) shows the experimental case, and Fig. 12(b) shows the comparative case.
In Figures 12(a) and (b), the upper distribution map V1 is a diagram showing the burner and its front area, and the lower distribution map V2 is an enlarged diagram of the burner portion (within the frame of the figure) of the above distribution map V1.

The symbols E1 and E2 shown in FIGS. 12A and 12B indicate the air flows (vectors) in the vicinity of the gas holes 43, respectively.
As a result, it was confirmed that the first opening and closing tube 451 of the front and rear slide of the practical case had a greater amount of air flowing from the air intake 44 to the gas hole 43 than the second opening and closing tube 452 of the rotation slide of the comparative case.

Figure 13 shows the standard deviation of the temperature near the wall for each blower suction pressure (-mmAq) in the first opening and closing tube 451 of the front and rear slide and the second opening and closing tube 452 of the rotating slide in the experimental furnace. The blower corresponds to the outer tube mentioned above. The blower suction pressures were -5mmAq, -10mmAq, and -15mmAq. As a result, it was confirmed that the standard deviation was smaller for the front and rear slides, and that the variation in the suction pressure, i.e., the amount of air supplied, was smaller.

Fifth Example
Next, a fifth example will be described. In the fifth example, corrosion performance was evaluated using a comparison case in which general structural rolled steel SS400 was used as the material for the inner tube, and an example case in which stainless steel SUS304 was used.
The corrosion test was carried out on the test specimens (execution case and comparison case) in an actual burner for 10 days at a maximum temperature of approximately 800°C around the gas nozzle (inner tube), and the state of oxide adhesion was visually confirmed.

The results of the above corrosion tests confirmed that no oxides were deposited in the case where SUS304 was used. Furthermore, it was confirmed that no blockage of the gas holes occurred even when used for a dry heating period of approximately 70 days.

The above describes an embodiment of the coke oven drying burner according to the present invention, but the present invention is not limited to the above embodiment and can be modified as appropriate without departing from the spirit of the invention.

For example, in the above-described embodiment, the radius of curvature R of the outer peripheral edge 41d of the nozzle tip 41a of the inner tube 41 is set to 5 mm or more, but is not limited to 5 mm or more, and the outer peripheral edge 41d may not be curved.

Furthermore, the relationship between the gas hole diameter d1 of the first row of gas holes 43 in the inner tube 41 and the gas hole diameter d2 of the second row and thereafter is not limited to satisfying the above formula (2).

Furthermore, the hole diameter ratio d1:d2 between the gas hole diameter d1 in the first row and the gas hole diameter d2 in the second row and thereafter is not limited to being 5:3 to 7:3.

In addition, in this embodiment, an opening/closing tube 45 that slides in the tube axis O direction is provided as a means for adjusting the opening amount of the multiple air intakes 44 formed in the outer tube 42 and that draw the first air A1 into the outer tube 42. However, the opening/closing tube 45 is not limited to this configuration, and other configurations may be used. For example, it is also possible to adopt a conventional opening/closing tube that rotates and slides around the tube axis O.

In addition, in this embodiment, a scale plate 46B with scale marks along the tube axis O direction is used as a positioning means for positioning the opening and closing cylinder 45, but other positioning means may be used.

Furthermore, in this embodiment, the relationship between the outer diameter dimension D and the length dimension T of the outer tube 42 is set to satisfy the above formula (3), but is not limited to this.

In addition, the components in the above-described embodiments may be replaced with well-known components as appropriate without departing from the spirit of the present invention.

1 Coke oven 10 Carbonization chamber 11 Oven wall 20 Combustion chamber
30 heat regenerator 40 burner (coke oven drying burner)
41 Inner tube 41a Nozzle tip 41b Outer surface 42 Outer tube 42a Inner surface 42B Air inlet tube 42C Primary air flow path 43 Gas hole 43A First row of gas holes 43B Second row of gas holes 44 Air intake port 45 Opening/closing tube 46 Guide 46B Scale plate (positioning means)
A1 Primary air A2 Secondary air E Fuel O Pipe axis

Claims (7)

A coke oven drying burner used to dry a furnace body at the time of lighting in a coke oven furnace body facility having a structure in which a combustion chamber and a carbonization chamber are alternately arranged above a heat storage chamber,
The fuel supply system has a double-pipe structure including an inner pipe through which fuel is supplied and an outer pipe through which air is naturally supplied.
The inner tube has a front end surface that is closed, and a front end side wall of the inner tube is provided with a plurality of gas holes arranged in a tube axial direction.
1. A coke oven drying burner, comprising: a nozzle tip side of the inner tube; a gas hole center line extending from the nozzle tip side to the gas hole center line; a gas hole diameter line extending from the nozzle tip side to the gas hole center line;

The coke oven drying burner according to claim 1, characterized in that the radius of curvature R of the outer peripheral edge of the nozzle tip of the inner tube is 5 mm or more. 3. The coke oven drying burner according to claim 1, wherein when the gas hole diameter of the first row of gas holes in the inner tube is d1 and the gas hole diameter of the second row and thereafter is d2, formula (2) is satisfied.

The coke oven drying burner described in claim 3, characterized in that the hole diameter ratio d1:d2 between the gas hole diameter d1 of the first row and the gas hole diameter d2 of the second row and thereafter is 5:3 to 7:3. The outer tube is formed with a plurality of air intakes spaced apart in a circumferential direction,
The air intake is formed in a long hole extending along a tube axis direction of the outer tube,
The outer tube is provided with an opening/closing cylinder that is coaxial with the outer tube and slidable in the tube axis direction,
5. The coke oven drying burner according to claim 1, wherein the opening and closing cylinder is positioned at any position between a fully closed position and a fully open position with respect to the air intake. The coke oven drying burner according to claim 5, characterized in that a positioning means is provided for positioning the opening and closing tube. A coke oven drying burner as described in any one of claims 1 to 3, characterized in that the relationship between the outer diameter dimension D of the outer tube and the length dimension T from the tip of the outer tube to the outer surface of the carbonization chamber in the axial direction of the outer tube satisfies equation (3).

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