JP2020186846A - Dust coal burner device, and burning method therefor - Google Patents

Abstract

To stably burn wet dust coal prepared by desalting a carbonized material obtained by carbonizing general waste, by a dust coal burner.SOLUTION: A dust coal burner 2 ejecting dust coal as burner fuel from a dust coal nozzle 5, is characterized in that a pair of outside air introduction nozzles 11 are connected to the dust coal nozzle 5 of a straight tube shape to generate a swirl flow in the vicinity of the ejection port of the dust coal nozzle 5, and outside air from the outside air introduction nozzles 11 is introduced in such a manner that its flow velocity can be adjusted, to inject a dust-coal/air mixture in the dust coal nozzle 5 into flame in a form of a prescribed swirl flow in a dispersed state to burn the dust coal.SELECTED DRAWING: Figure 1

Description

The present invention relates to a pulverized coal burner device using pulverized coal as a fuel for carbonized products of general waste such as municipal waste, and a combustion method thereof.

Use of fossil fuels by carbonizing general waste (city waste, etc.) that has been incinerated in the past under low oxygen or anoxic conditions to obtain carbides, and replacing the carbides with a part of fossil fuels. The amount is reduced and the environmental load is reduced.

However, chlorine is contained in the carbides made from general waste as a raw material, and there is a concern that dioxin may be generated when burning as fuel. Therefore, for example, the generated carbides are put into a water tank and run water. Desalting treatment such as washing with water to wash out chlorine is performed. Then, it is dehydrated to a certain extent (for example, about 30% in terms of water content) with a dehydrator (filter press or the like), and then dried to an absolutely dry state with a dryer.

Then, the carbonized material that has undergone the desalting treatment is, for example, pelletized and put into an incinerator or the like for use as an auxiliary fuel, or finely carbonized by a crusher (mill or the like) and used as a burner fuel. It should be noted that, after the desalting treatment, after dehydration, if the product is kept in a moist state with a certain amount of moisture remaining without being dried, problems such as dust explosion and spontaneous combustion may be prevented and the handleability may be improved. ..

As the pulverized coal burner, for example, as in Patent Documents 1 and 2, a plurality of pulverized coal nozzles are arranged around the heavy oil nozzles, and the pulverized coal from each pulverized coal nozzle is placed in a flame formed in front of the heavy oil nozzles. There is a configuration in which pulverized coal in the air-fuel mixture is gasified and burned by injecting and injecting an air-fuel mixture of the air-fuel mixture.

Further, as in Patent Document 3, a supply duct for supplying an air-fuel mixture of pulverized coal and pumped air is connected to the pulverized coal nozzle in the orthogonal direction, and the air-fuel mixture is formed in front of the heavy oil nozzle so as to form a swirling flow. There is a structure that effectively mixes with the flame and gasifies and burns it.

JP-A-2019-27647 Japanese Unexamined Patent Publication No. 2019-27648 JP-A-2017-15305

However, when attempting to pulverize and supply the wet carbide to the burner, in Patent Documents 1 and 2, adhesion and blockage occur at the curved tube portion in the middle of the pulverized coal nozzle, and there is a possibility of misfire.

Further, in Patent Document 3, since the supply duct and the pulverized coal nozzle are connected in the orthogonal direction, adhesion and blockage are likely to occur at the orthogonal portion.

Further, when the pulverized coal is in a wet state of about 30%, the particles of the pulverized coal are easily attracted to each other (due to surface tension), and as a result of increasing the particle size, the dispersibility at the time of injection from the nozzle tip is lowered. Therefore, it may not be properly blown into the flame, and the gasification / combustion efficiency may decrease. Therefore, it has been a problem to make the carbides washed with water by desalting treatment properly combustible with a pulverized coal burner while keeping them in a wet state in order to improve handling.

In view of the above points, the present invention is a pulverized coal burner in which pulverized coal is injected from a pulverized coal nozzle to be used as a burner fuel as described in claim 1 in order to solve the above-mentioned problems. The charcoal nozzle is a straight tube, and an outside air introduction nozzle that generates a swirling flow is connected near the injection port of the pulverized coal nozzle, and the flow velocity of the outside air from the outside air introduction nozzle is tunably introduced to introduce the air-fuel mixture in the pulverized coal nozzle. It is an object of the present invention to provide a pulverized coal burner device characterized in that the pulverized coal burner is blown into a flame in a dispersed state as a swirling flow.

Further, as described in claim 2, the outside air introduction nozzles are connected to both sides of the pulverized coal nozzle from the tangential direction, and the outside air flow velocity adjusting device is provided in the outside air introduction nozzle so that the flow velocity of the outside air can be adjusted, and the burner combustion amount. It is an object of the present invention to provide a pulverized coal burner apparatus characterized in that the pulverized coal is stably combusted by adjusting the flow velocity of the introduced outside air in accordance with the above.

Further, as described in claim 3, the wet pulverized coal is supplied from the pulverized coal nozzle to the pulverized coal burner, and the high temperature gas discharged from the pulverized coal burner is introduced into the base end portion of the pulverized coal nozzle. It is an object of the present invention to provide a pulverized coal burner device, which is characterized in that the pulverized coal is heated in such a manner.

Further, as described in claim 4, after desalting the charcoal obtained by carbonizing general waste, undried wet pulverized coal is injected from the pulverized coal nozzle to be used as a burner fuel. It is a combustion method, in which an outside air introduction nozzle that generates a swirling flow is connected near the injection port of a straight tubular pulverized coal nozzle, and the flow velocity of the outside air from the outside air introduction nozzle is adjustablely introduced into the pulverized coal nozzle. It is an object of the present invention to provide a pulverized coal burner combustion method, which comprises blowing an air-fuel mixture of the above into a flame in a dispersed state as a swirling flow.

The pulverized coal burner device according to the present invention is a pulverized coal burner in which pulverized coal is injected from a pulverized coal nozzle to be used as burner fuel as described in claim 1, and the pulverized coal nozzle is a straight tube. An outside air introduction nozzle that generates a swirling flow is connected near the injection port of the nozzle, and the flow velocity of the outside air from the outside air introduction nozzle is adjustablely introduced so that the air-fuel mixture in the pulverized coal nozzle is swirled and is in a dispersed state. By blowing into the pulverized coal, the pulverized coal may adhere to the pulverized coal nozzle even if it is undried and wet pulverized coal, especially after desalting the carbide obtained by carbonizing the general waste. Without clogging, the required flow rate of the outside air can be adjusted so that the flame is properly blown into the flame formed in front of the heavy oil nozzle in a dispersed state and can be properly burned by the pulverized coal burner. Further, when the pulverized coal is in a wet state, problems peculiar to pulverized coal such as dust explosion and spontaneous combustion can be solved, handleability is improved, and combustion treatment can be performed as described above.

Further, in the pulverized coal burner device, as described in claim 2, the outside air introduction nozzles are connected to both sides of the pulverized coal nozzle from the tangential direction, respectively, and the flow velocity of the outside air can be adjusted freely to the outside air introduction nozzle. By adjusting the flow velocity of the introduced outside air according to the amount of burner combustion so that the pulverized coal is stably burned, the flow velocity of the outside air can be freely adjusted by the outside air introduction nozzle from the tangential direction on both sides of the pulverized coal nozzle. By introducing it, the air-fuel mixture in the pulverized coal nozzle can be used as a swirling flow to properly adjust the pulverized coal injection angle, and it can be properly blown into the flame according to the amount of burner combustion, and the pulverized coal can be burned stably. it can.

Further, the pulverized coal burner device supplies the pulverized coal in a wet state from the pulverized coal nozzle to the pulverized coal burner as described in claim 3, and the high temperature gas discharged from the pulverized coal burner is supplied to the pulverized coal nozzle. By connecting so as to be introduced into the base end to heat the pulverized coal, the wet pulverized coal supplied to the pulverized coal nozzle is heated and dried by the high temperature gas discharged from the pulverized coal burner. It is possible to prevent the pulverized coal from adhering to or blocking the pulverized coal nozzle, and as described above, the dispersibility at the time of injection can be improved and the pulverized coal burner can be properly burned.

Furthermore, in the pulverized coal burner combustion method, as described in claim 4, after carbonizing the carbonized material obtained by carbonizing general waste, undried and wet pulverized coal is injected from the pulverized coal nozzle. It is a pulverized coal burner combustion method using a burner fuel, and the flow velocity of the outside air from the outside air introduction nozzle can be adjusted by connecting an outside air introduction nozzle that generates a swirling flow near the injection port of the straight tubular pulverized coal nozzle. By blowing the air-fuel mixture in the pulverized coal nozzle into a flame in a dispersed state as a swirling flow, the carbonized material obtained by carbonizing general waste is desalted and then undried and wet pulverized coal. Even so, the pulverized coal does not adhere to or block the pulverized coal nozzle, and the required outside air flow velocity is adjusted so that the pulverized coal is properly blown into the flame formed in front of the heavy oil nozzle in a dispersed state. It can be burned properly with a charcoal burner. Further, when the pulverized coal is in a wet state, problems peculiar to pulverized coal such as dust explosion and spontaneous combustion can be solved, handleability is improved, and combustion treatment can be performed as described above.

Schematic diagram of an embodiment of the present invention, Enlarged sectional view of the burner body as above, AA cross-sectional view of the pulverized coal burner part as above, BB sectional view of the throat portion of the same as above, Schematic diagram of the same test facility, Illustration of injection angle measurement as above, The relationship between the flow velocity of the introduced outside air and the injection angle as above, Explanatory drawing of adhesion state in pipe of pulverized coal nozzle of the same as above (a), (b) Same as above, particle size distribution chart after pulverized coal injection.

The pulverized coal burner device and its combustion method of the present invention are pulverized coal burners that inject pulverized coal from a pulverized coal nozzle to be used as burner fuel, and the pulverized coal nozzle is a straight tube in the vicinity of the injection port of the pulverized coal nozzle. The outside air introduction nozzle that generates a swirling flow is connected to the outside air introduction nozzle, and the flow velocity of the outside air from the outside air introduction nozzle is adjustablely introduced to blow the air-fuel mixture in the pulverized coal nozzle into the flame in a dispersed state as a swirling flow. It is supposed to be.

As shown in FIG. 1, the pulverized coal burner device 1 connects a truncated cone-shaped throat 4 to the tip of a cylindrical burner main body 3 of the pulverized coal burner 2, and injects pulverized coal into the center thereof. The pulverized coal nozzle 5 is arranged as a straight cylinder, and heavy oil nozzles 6 are provided on both sides thereof so that the pulverized coal nozzle 5 can be burned with a required thermal power.

Inside the throat 4 in front of these nozzles 5 and 6, a flame-retaining plate 7 having an annular diameter slightly larger than the inner diameter of the burner body 3 is provided, and the throat in front of the flame-retaining plate 7 from each of the nozzles 5 and 6 described above. It is designed to blow into the flame region formed in 4.

As shown in FIG. 1, a rotary valve 9 is connected to the rear end of the pulverized coal nozzle 5 so that pulverized coal can be cut out from the pulverized coal storage bin 8 for storing the pulverized coal, and a pulverized coal blower 10 for pumping the pulverized coal. Is arranged, and the pulverized coal cut out by the rotary valve 9 is pressure-fed to the pulverized coal nozzle 5 by the air blown by the pulverized coal blower 10 to be supplied.

An outside air introduction nozzle is provided near the injection port at the front portion of the pulverized coal nozzle 5 having an inverted tapered tip in order to generate a swirling flow horizontally or vertically symmetrically from the tangential direction on both sides of the pulverized coal nozzle 5. 11 are connected to each other, and the air-fuel mixture in the pulverized coal nozzle 5 is swirled by introducing outside air so that the air-fuel mixture can be blown into the flame in a dispersed state at the time of injection. Reference numeral 12 denotes a blower amount adjusting device for the inverter, which makes it possible to adjust the blower amount of the pulverized coal blower 10 according to the amount of pulverized coal cut out from the pulverized coal storage bottle 8.

The connection position of the outside air introduction nozzle 11 is such that the turning force is attenuated when the distance from the nozzle tip becomes long, and conversely, a sufficient turning effect cannot be obtained even if the distance is too close, and the connection position is about 100 to 200 mm from the nozzle tip. The position is preferable. Further, the outside air inflow velocity from the outside air introduction nozzle 11 is about 70 to 120 m / s, and the flow velocity of the air-fuel mixture in the pulverized coal nozzle 5 is about 10 to 20 m / s so that the mixture can be blown into the flame in a swirling state. ..

When the outside air introduction nozzle 11 is connected to the pulverized coal nozzle 5 so that it can be connected to the inner peripheral surfaces thereof from the tangential direction without a step, the outside air is connected to the inner wall surface of the pulverized coal nozzle 5 as shown in FIG. It swirls smoothly along the line, and the pulverized coal that is pumped can be effectively injected as a swirling flow in a dispersed state at the time of injection, which is preferable because an appropriate flame can be obtained. As shown in FIGS. 1 and 2, the outside air introduction nozzle 11 is preferably connected in a substantially orthogonal state with respect to the longitudinal direction of the pulverized coal nozzle 5 so that the air-fuel mixture can be most efficiently provided with a turning force. It can also be connected in a state of inclination of about several tens of degrees in the front-rear direction within a range in which a swirling flow can be generated.

As shown in FIG. 4, the heavy oil fuel supplied from the heavy oil tank can be freely supplied to the heavy oil nozzles 6 provided on both sides of the pulverized coal nozzle 5 by the heavy oil supply pump 13 and the flow rate adjusting valve 14, respectively. The pulverized coal injected from the pulverized coal nozzle 5 is blown into the flame region formed in front of each heavy oil nozzle 6 to gasify and ignite and burn.

As shown in FIG. 1, a combustion air blower 16 for supplying combustion air is disposed at the rear end of the burner main body 3 via a ventilation duct 15, and the combustion air blower 16 is provided via an inverter air volume adjusting device 17. The amount of air blown by the air blower 16 is adjusted so that the amount of combustion air corresponding to the amount of burner combustion can be supplied to the burner main body 3. Reference numeral 18 denotes an outside air blower that supplies outside air to the outside air introduction nozzle 11, and reference numeral 19 denotes an air volume adjusting device for the inverter.

When the burner combustion amount is fully opened, the amount of air blown from the combustion air blower 16 increases and the back pressure on the back surface of the flame holding plate 7 increases, and as a result, the flame formed in front of the heavy oil nozzle 6 holds the flame. It is strongly attracted to the plate 7 side and is close to the flame holding plate 7 (f1 in FIG. 2). On the other hand, when the burner combustion amount decreases, the amount of air blown from the combustion air blower 16 decreases and the back pressure on the back surface of the flame holding plate 7 decreases, and as a result, the position of the flame in front of the heavy oil nozzle 6 is the flame holding plate 7. (F2 in FIG. 2).

Further, as the outside air flow velocity is faster, a turning force is applied to the air-fuel mixture in the pulverized coal nozzle 5, the dispersibility is increased, and the injection angle at the time of pulverized coal injection is widened (α1 in FIG. 2). On the contrary, when the outside air flow velocity is slow, the dispersion force decreases, and the injection angle at the time of pulverized coal injection becomes narrow (α2 in FIG. 2). In this way, there is a correlation between the outside air flow velocity and the pulverized coal injection angle, and the flame that moves back and forth (left and right in FIG. 2) in the throat 4 according to the burner combustion amount is introduced from the outside air introduction nozzle 11. By adjusting the flow velocity of the outside air to adjust the injection angle of the pulverized coal, the pulverized coal can always be properly blown into the flame, and the pulverized coal can be stably gasified and burned without any unburned content. In this embodiment, the pulverized coal injection angle can be adjusted in the range of about 45 to 75 degrees.

Further, the pulverized coal burner device 1 is provided with a combustion controller 20 and the like to operate and output the rotary valve 9, the pulverized coal blower 10, the heavy oil supply pump 13, the combustion air blower 16, the outside air blower 18, and the like. It corresponds to the burner combustion required when operating the device, and it is possible to properly adjust and control the increase and decrease.

The high temperature gas discharged from the pulverized coal burner 2 is introduced into the base end of the pulverized coal nozzle 5 to heat the pulverized coal, and the discharged high temperature gas heats the wet pulverized coal. It can also be dried.

In the present invention, in particular, pulverized coal in an undried wet state (for example, a water content of about 30%) after desalting and dehydrating a carbide obtained by carbonizing general waste such as municipal waste can be targeted. it can. By maintaining the water content at about 30% after desalting and without drying, problems such as dust explosion and spontaneous combustion can be improved, handling can be improved, and there is no problem as burner fuel. It is effective because it can be used and its uses can be expanded. The present invention can be suitably applied to wet pulverized coal that easily adheres, but can also be applied to various dry pulverized coals.

The following is an embodiment of the present invention. As shown in FIGS. 1 and 2, the pulverized coal burner device 1 connects a truncated cone-shaped throat 4 to the tip of the cylindrical burner main body 3 of the pulverized coal burner 2, and injects pulverized coal into the center thereof. A pulverized coal nozzle 5 having a predetermined diameter is arranged as a straight cylinder, heavy oil nozzles 6 are provided on both sides thereof as shown in FIGS. 3 and 4, and the nozzles 5 and 6 are placed in the throat 4 in front of the flame holding plate 7. It is designed to blow into the flame area that is formed.

The tip of the pulverized coal nozzle 5 has an inverted tapered shape, and is symmetrical from the tangential direction on both sides of the pulverized coal nozzle 5 at a position of about 100 to 200 mm from the nozzle tip near the injection port in the front portion as shown in FIGS. The outside air introduction nozzle 11 for generating a swirling flow is connected orthogonally to the longitudinal direction of the pulverized coal nozzle 5, and the air-fuel mixture in the pulverized coal nozzle 5 is swirled by the introduction of the outside air, and the burner combustion amount Depending on the situation, it is possible to blow into the flame in the required dispersed state at the time of injection.

The pulverized coal burner device 1 was tested at the test facility shown in FIG. In FIG. 5, 101 is the test apparatus, 105 is a pulverized coal nozzle, 108 is an input hopper for charging pulverized coal, 109 is a rotary valve, 110 is a pulverized coal blower, 111 is an outside air introduction nozzle, 118 is an outside air blower, and 121 is an outside air blower. The screw conveyor, 122 and 123 are air volume sensors, 124 is a temperature sensor, and 125 is a camera.

In addition, in this test apparatus 101, in order to confirm the injection state of pulverized coal, only the injection test of pulverized coal was performed without actually performing combustion. In the test, the amount of air blown from the pulverized coal blower 110 and the outside air blower 118 is detected by the air volume sensors 122 and 123, each flow velocity is calculated, and the temperature sensor 124 immediately after injection from the nozzle tip (1 m point). ), The outlet air temperature was detected, the injection state of the pulverized coal was photographed by the camera 125, and the injection angle was measured based on the image data. The pulverized coal injection angle α is an angle connecting the outer edges of the injection region at a point 250 mm from the center of the tip of the pulverized coal nozzle 105 as shown in FIG.

Carbonized fuel of pulverized coal in a wet state (moisture content of about 31 to 33%) is cut out from a hopper 108 via a screw conveyor 121 by a rotary valve 109 and fed into a straight tubular pulverized coal nozzle 105, and is supplied to a pulverized coal blower. It was pumped with the required amount of pumped air at 110, and pulverized coal was injected under the following conditions.

The connection position of the outside air introduction nozzle 111 is 150 mm from the nozzle tip, the pulverized coal supply amount is 90 kg / h, the pulverized coal pressure feed air flow velocity is 15 m / s, and the introduced outside air flow velocity is 50 m / s (low speed) or 100 m / s (high speed). ), And the outlet air temperature of the pulverized coal nozzle 105 was tested in two patterns of 10 ° C. (normal temperature) or 90 ° C. (high temperature). The results are shown in FIG.

When the outlet air temperature of the pulverized coal nozzle 105 is 10 ° C., the injection angle of the pulverized coal is about 38 ° (No. 1) when the wind speed of the introduced outside air is 50 m / s, and the flow velocity of the introduced outside air is 100 m / s. Occasionally, the injection angle of the pulverized coal was about 61 ° (No. 2), and it was confirmed that the injection angle of the pulverized coal increased as the flow velocity of the introduced outside air increased.

When the outlet air temperature is 90 ° C., the injection angle of the pulverized coal is about 49 ° (No. 3) when the wind speed of the introduced outside air is 50 m / s, and the pulverized coal is when the wind speed of the introduced outside air is 100 m / s. The injection angle of pulverized coal was about 72 ° (No. 4), and it was confirmed that the injection angle of pulverized coal was slightly increased by increasing the outlet air temperature. At this time, when the water content of the pulverized coal injected from the pulverized coal nozzle 105 was confirmed, it was about 29 to 30% when the outlet air temperature was 10 ° C., whereas it was about 21 to 23% when the outlet air temperature was 90 ° C. The water content has decreased by about 7 to 8%, and it is expected that this is because the dispersibility of the pulverized coal has improved with heating and drying with high-temperature pumped air.

Further, FIG. 8 shows the state of adhesion of pulverized coal in the pulverized coal nozzle 105 pipe, and when the outlet air temperature of the pulverized coal nozzle 105 is 10 ° C. as shown in FIG. 8A, it is located near the outside air introduction port. A small amount of pulverized coal deposits were confirmed, and when the outlet air temperature was set to 90 ° C. as shown in FIG. 8 (b), no deposits were confirmed. It is presumed that this is also due to the fact that the adhesion of the pulverized coal was reduced due to heating and drying with high-temperature pumped air.

Further, FIG. 9 is a distribution diagram of the particle size of the pulverized coal immediately after injection from the pulverized coal nozzle 105, and when the outlet air temperature of the pulverized coal nozzle 105 is 90 ° C. (No. 4), 10 ° C. (No. 2). ), The peak of 500 to 600 μm disappears. It is presumed that this is also due to the fact that the adhesive force (surface tension) between the pulverized coals decreased with the heating and drying by the high-temperature pumped air, and the particle size became finer.

INDUSTRIAL APPLICABILITY The present invention can be widely used for pulverized coal obtained by carbonizing general waste such as municipal waste, particularly pulverized coal burner using undried and wet pulverized coal as fuel after desalting treatment.

1 ... pulverized coal burner device 2 ... pulverized coal burner 4 ... throat 5 ... pulverized coal nozzle 11 ... outside air introduction nozzle

Claims (4)

A pulverized coal burner that injects pulverized coal from a pulverized coal nozzle and uses it as burner fuel. The pulverized coal nozzle is a straight tube, and an outside air introduction nozzle that generates a swirling flow is connected to the vicinity of the injection port of the pulverized coal nozzle.
A pulverized coal burner device characterized in that the flow velocity of the outside air from the outside air introducing nozzle is tunably introduced so that the air-fuel mixture in the pulverized coal nozzle is blown into a flame in a dispersed state as a required swirling flow. The outside air introduction nozzle is connected to both sides of the pulverized coal nozzle from the tangential direction, and the outside air flow velocity adjusting device is provided in the outside air introduction nozzle so that the flow velocity of the outside air can be adjusted freely, and the flow velocity of the introduced outside air can be increased or decreased according to the burner combustion amount. The pulverized coal burner device according to claim 1, wherein the pulverized coal is stably combusted. Wet pulverized coal is supplied from the pulverized coal nozzle to the pulverized coal burner, and the high-temperature gas discharged from the pulverized coal burner is connected so as to be introduced into the base end portion of the pulverized coal nozzle to heat the pulverized coal. The pulverized coal burner device according to claim 1 or 2, wherein the pulverized coal burner device is characterized in that. A pulverized coal burner combustion method in which undried wet pulverized coal is injected from a pulverized coal nozzle to be used as burner fuel after desalting the carbide obtained by carbonizing general waste.
An outside air introduction nozzle that generates a swirling flow is connected near the injection port of the straight tubular pulverized coal nozzle, and the flow velocity of the outside air from the outside air introducing nozzle is adjustedly introduced to swirl the air-fuel mixture in the pulverized coal nozzle. A method of burning a pulverized coal burner, which is characterized by blowing into a flame in a dispersed state.