TW202037847A - Powder fuel combustion apparatus and combustion method - Google Patents

Abstract

To provide a combustion apparatus and a combustion method that, without disposing a device such as an uncombusted amount measurement device and without making variable the direction of air injection into a combustion chamber, enables efficient ashing of an object to be combusted in the combustion chamber. A powder fuel combustion apparatus 1 is provided with a fuel supply device 10, a primary combustion chamber 20, a secondary combustion chamber 50, an air supply/ash discharge device 32, and a cyclone dust collecting machine 60. An inclination section 23a is formed at a bottom part 23 of the primary combustion chamber 20, and the inclination section 23a has a bottom part air supply port 31 and the air supply/ash discharge device 32. The air supply/ash discharge device 32 is provided with a bottom part air injection nozzle 34 and an ash delivery device 35. The upper end and the lower end of the bottom part air injection nozzle 34 are open, and a plurality of injection ports 34a from which air is injected are provided to the side surface of the bottom part air injection nozzle 34. Air with strong wind pressure is injected regularly or irregularly from the bottom part air injection nozzle 34 during combustion of powder fuel F, and the powder fuel F is stirred, to obtain a good combustion state.

Description

Powder fuel combustion device and combustion method

The present invention relates to a combustion device for burning powder fuel and a combustion method of the combustion device.

In the past, it has been known that boilers use pulverized coal as fuel for combustion, recover combustion heat and supply superheated steam to power plants (see Patent Document 1). The boiler described in Patent Document 1 is provided with a hollow-shaped furnace arranged in a vertical direction, and three burners arranged in a vertical direction for the purpose of injecting a pulverized coal mixture gas formed by mixing solid fuel and combustion air into the furnace. Device.

In addition, the boiler has a bottom air nozzle for injecting combustion air into the furnace below the burner in the vertical direction, and a horizontal adjustment device that can adjust the direction in which the bottom air nozzle sprays the combustion air in the horizontal direction. . The boiler of Patent Document 1 is configured in this way to promote the combustion of fuel in the furnace and suppress the generation of unburned parts.

As a fuel, the boiler described in Patent Document 1 mainly uses pulverized coal obtained by grinding coal as a pulverized fuel (solid fuel), as described in paragraphs 0027 and 0051 of the publication.

On the other hand, the inventors of the present invention used the carbonized fuel production device and the carbonized fuel production method disclosed in Patent Document 2 to produce high-quality carbonized fuel using synthetic resin and the like recovered mainly for reuse as raw materials.

According to the carbonized fuel production device and the carbonized fuel production method disclosed in Patent Document 2, even if the recycled synthetic resin is of poor quality and is not suitable for regeneration, it can also be used as a carbonized fuel having a heat of combustion close to coal. Therefore, even synthetic resins that are recovered but difficult to reuse or synthetic resins that can only be buried and processed can be regenerated as higher-quality fuels, thereby achieving excellent effects such as recycling synthetic resins and reducing the burden on landfills.

[Prior technical literature] [Patent Literature] Patent Document 1: Japanese Patent Laid-Open No. 2017-145976. Patent Document 2: International Publication No. 2018/074189.

[The problem to be solved by the invention] The boiler of Patent Document 1 is configured such that three burners are installed in the longitudinal direction in a vertically long furnace to burn pulverized coal in the furnace, but unburnt materials are deposited on the bottom of the furnace. In Patent Document 1, the pulverized coal deposited on the bottom of the furnace is introduced into combustion air from a bottom air nozzle to incinerate the unburnt in the bottom of the furnace.

In addition, in the boiler of Patent Document 1, as shown in FIG. 9 of the publication, a hopper is provided at the bottom of the furnace to store ash or unburned parts. In the boiler of Patent Document 1, the ash or unburned part stored in the feed hopper is analyzed using an unburned part quantity measuring device and an unburned part analysis device installed at the bottom of the feed hopper, and then the bottom air is adjusted. The direction in which the nozzle sprays air is controlled to reduce the amount of unburned part.

As described in Patent Document 1, the measurement device of the unburned part and the analysis device of the unburned part, or the structure where the spray direction of the air nozzle can be changed, if it is applied to large-scale equipment, it can be technically or cost-effectively上处理。 On processing. However, if it is applied to a small device, the device structure becomes complicated and the installation cost increases. Moreover, the variable mechanisms of the measuring devices and nozzles require daily maintenance, which is inconvenient to increase operating costs.

In order to solve the above inconvenience, the purpose of the present invention is to provide a combustion device and a combustion method, which do not need to be equipped with an unburned part quantity measuring device and an unburned part analysis device, and it does not need to be configured to be able to spray air into the combustion chamber It can effectively ash the burned materials in the combustion chamber.

[Means for solving problems] In order to achieve the above-mentioned object, the powder fuel combustion device of the present invention is a combustion device that burns powder fuel, and is characterized in that the powder fuel combustion device includes a primary combustion chamber for burning the powder fuel inside; And a secondary combustion chamber for burning the combustion gas discharged from the primary combustion chamber; the primary combustion chamber is provided with a fuel supply device for supplying the powder fuel to the inside; a primary air supply port for Supply air to the inside; and an ignition burner to ignite the powder fuel inside; the bottom of the primary combustion chamber is provided with: an inclined part, which is inclined in a way that the bottom narrows in the past; a bottom air supply port for supply Air to the inside; an ash discharge port, which is located below the inclined part; and a bottom air jet nozzle, which is cylindrical and arranged in the up and down direction, has openings at the upper and lower ends, and the lower end is set toward the ash discharge port, and It is used to supply air to the inside; the secondary combustion chamber is provided with: a secondary burner for heating the interior and igniting the combustion gas discharged from the primary combustion chamber; and a secondary air supply port for supplying combustion Use air to the inside; the powder fuel combustion device is equipped with: a primary air supply device to supply air to the primary air supply port and the bottom air supply port; jet air supply device to supply air to the bottom air injection nozzle ; Secondary air supply device for supplying air to the secondary air supply port; and control device for controlling the fuel supply device, the ignition burner, the secondary burner, the primary air supply device, the injection The air supply device and the operation of the secondary air supply device.

The control device is: the fuel supply device causes the powder fuel to deposit a predetermined amount in the primary combustion chamber, and the ignition burner ignites the deposited powder fuel and at the same time activates the secondary burner And heating the secondary combustion chamber, when the deposited powder fuel is vaporized and burned, the primary air supply device and the injection air supply device are activated, and the primary air supply port, the bottom air supply port, And when the bottom air injection nozzle is supplied with an air volume less than the air volume required to completely combust the deposited powder fuel to generate combustible gas in the primary combustion chamber, when the deposited powder fuel is directly burned , Actuate the primary air supply device and the injection air supply device, and supply the amount of air required for direct combustion of the powder fuel from the primary air supply port, the bottom air supply port, and the bottom air injection nozzle Into the primary combustion chamber, the fuel supply device is activated at the same time, the powder fuel is supplied into the primary combustion chamber and burned, the fuel supply device as a burner is activated, and the deposited powder fuel is activated. During gasification and combustion, and when the deposited powder fuel is directly burned, the secondary air supply device is activated, and the amount of air required for complete combustion of the combustible gas is supplied from the secondary air supply port The secondary combustion uses air to burn the combustible gas.

In the powder fuel combustion device of the present invention, when the deposited powder fuel is vaporized and burned, air is supplied from the primary air supply port, the bottom air supply port, and the bottom air injection nozzle fixed to the primary combustion chamber, and the Combustible gas is generated in the combustion chamber, not only the primary air supply port and the bottom air supply port, but also the bottom air injection nozzles. In the present invention, the powder fuel can be completely combusted with such a configuration, so that it is not necessary to analyze the unburned part and to change the angle of the primary air supply nozzle.

In addition, in the powder fuel combustion device of the present invention, when the powder fuel in the primary combustion chamber is burned and ashed, the fuel supply from the fuel supply device can be stopped, and the bottom air injection nozzle can be stopped at the same time. air.

In the powder fuel combustion device of the present invention, according to the composition of the powder fuel, when the powder fuel in the primary combustion chamber is burnt and ashed, white smoke may be generated in the primary combustion chamber and the secondary combustion chamber, and It places a burden on the cyclone dust collector and bag filter installed below the secondary combustion chamber.

As a result of diligent research, the inventors found that when white smoke is generated during ember combustion and ashing, there is no need to use auxiliary burners and secondary burners to heat the primary and secondary combustion chambers. Stopping the air supply from the bottom air jet nozzle can prevent the generation of this white smoke. Therefore, when the powder fuel in the primary combustion chamber is burned and ashed, if white smoke is generated in the primary combustion chamber or the secondary combustion chamber, the air supply from the bottom air injection nozzle may be stopped.

In addition, in the powder fuel combustion device of the present invention, when the deposited powder fuel is vaporized and combusted, and when the deposited powder fuel is directly burned, the control device can periodically or irregularly The injection air supply device is controlled so that the injection amount of the powder fuel can be stirred to inject air to the bottom air injection nozzle.

According to this control, air is injected from the bottom air injection nozzle regularly or irregularly to agitate the powder fuel, so that the powder fuel can be prevented from being fixed on the furnace bottom wall surface, and the powder fuel can be burned efficiently.

In addition, in the powder fuel combustion device of the present invention, the fuel supply device includes: a fuel hopper for feeding the powder fuel; and an injection nozzle for the hopper, which is installed upward and downward in the fuel hopper. It is used to inject air at least downward; the air supply device for the hopper is used to supply air to the injection nozzle for the hopper; the fuel delivery device is provided below the injection nozzle for the hopper and is used to convey the powder downward Fuel; a mixing tube for mixing the powdered fuel and air; and a fuel blower for supplying air to the mixing tube; the control device is configured to supply the powdered fuel to the primary combustion chamber While the fuel blower is activated, the fuel delivery device is activated, and the powder fuel is mixed with the air supplied by the fuel blower inside the mixing pipe, and the powder fuel is supplied to the primary through the mixing pipe. In the combustion chamber, the air supply device for the hopper is operated at a predetermined time point to inject air from the injection nozzle for the hopper.

According to this structure, the air supply device for the hopper can smoothly transfer the powdered fuel in the fuel hopper to the fuel transfer device, so that the powdered fuel can be stably supplied from the mixing pipe into the primary combustion chamber.

In addition, the pulverized fuel combustion method of the present invention is a combustion method that uses a pulverized fuel combustion device to combust pulverized fuel, and is characterized in that the combustion method includes a fuel injection step, an ignition step, a gasification combustion step, a direct combustion step, And the embers and ashing steps; the powder fuel combustion device is provided with: a primary combustion chamber for burning the powder fuel inside; and a secondary combustion chamber for burning the gas discharged from the primary combustion chamber The primary combustion chamber is provided with: a fuel supply device for supplying the powder fuel to the inside; a primary air supply port for supplying air to the inside; and an ignition burner for the powder fuel inside Ignition; The bottom of the primary combustion chamber is provided with: an inclined part, which is inclined in a way of narrowing down in the past; an air supply port at the bottom for supplying air to the inside; an ash discharge port, which is provided below the inclined part; and the bottom The air jet nozzle is cylindrical and arranged facing up and down, with openings at the upper and lower ends, and the lower end is set toward the ash discharge port, and is used to supply air to the inside; the secondary combustion chamber is provided with: A burner for heating the interior and igniting the combustion gas discharged from the primary combustion chamber; and a secondary air supply port for supplying combustion air to the interior; the powder fuel combustion device is equipped with: a primary air supply device for To supply air to the primary air supply port and the bottom air supply port; jet air supply device to supply air to the bottom air injection nozzle; secondary air supply device to supply air to the secondary air supply port; And a control device for controlling the operation of the fuel supply device, the ignition burner, the secondary burner, the primary air supply device, the injection air supply device, and the secondary air supply device.

By the control device, in the fuel input step, the fuel supply device is used to deposit a predetermined amount of the powder fuel in the primary combustion chamber; in the ignition step, the secondary burner is used to heat the secondary In the combustion chamber, after the temperature of the secondary combustion chamber reaches a predetermined temperature, the deposited powder fuel is ignited by the ignition burner; in the gasification combustion step, from the primary air supply port, the bottom air The supply port and the bottom air injection nozzle are supplied with an amount of air less than the amount of air required to completely combust the deposited powder fuel to generate combustible gas in the primary combustion chamber, and introduce the combustible gas to the secondary In the combustion chamber, the secondary combustion air is supplied from the secondary air supply port to completely burn the combustible gas; in the direct combustion step, the primary air supply device and the injection air supply device are activated, and the The primary air supply port, the bottom air supply port, and the bottom air injection nozzle supply the amount of air required for direct combustion of the powder fuel into the primary combustion chamber, and at the same time activate the fuel supply device to supply the powder The bulk fuel enters the primary combustion chamber and is combusted, the fuel supply device as a burner is activated, the combustion gas discharged from the primary combustion chamber is introduced into the secondary combustion chamber, and the secondary air supply port is supplied to the secondary combustion chamber. The air is used for the secondary combustion to completely burn the combustion gas; in the embers and ashing step, the fuel supply from the fuel supply device is stopped, and the powdered fuel ashes remaining in the primary combustion chamber are burned and ashed.

The powder fuel combustion method of the present invention is composed of a fuel input step, an ignition step, a gasification combustion step, a direct combustion step, and an embers and ashing step. In this gasification and combustion step, air is supplied from the primary air supply port, bottom air supply port, and bottom air injection nozzle to generate combustible gas in the primary combustion chamber. Not only the primary air supply port, the bottom air supply port, but also the bottom The air jet nozzle jets air. Therefore, by injecting air to the powdered fuel deposited in the bottom of the conventionally inclined bottom that is narrowed downward, the powdered fuel can be surely burned compared to the conventional incineration method.

In the powder fuel combustion method of the present invention, in the embers and ashing step, the air supply from the bottom air injection nozzle can be stopped. This treatment can prevent the generation of white smoke during the embers and ashing steps of the powdered fuel.

In addition, in the powder fuel combustion method of the present invention, in the gasification combustion step and the direct combustion step, the control device can periodically or irregularly inject air at an injection amount that can stir the powder fuel. The way to the bottom air jet nozzle is to control the jet air supply device. With this control, the powder fuel deposited at the bottom of the primary combustion chamber can be stirred, and compared to the previous incineration method, the powder fuel can be reliably burned.

In addition, in the powder fuel combustion method of the present invention, the fuel supply device has: a fuel hopper for feeding the powder fuel; and an injection nozzle for the fuel hopper, which is installed upward and downward in the fuel hopper It is used to inject air at least downward; the air supply device for the hopper is used to supply air to the injection nozzle for the hopper; the fuel delivery device is provided below the injection nozzle for the hopper and is used to convey the powder downward Fuel; a mixing tube for mixing the powder fuel and air; and a fuel blower for supplying air to the mixing tube. In the fuel input step and the direct combustion step, the fuel can be made by the control device The fuel delivery device is actuated by a blower, and the powder fuel is mixed with the air supplied by the fuel blower inside the mixing pipe, and the powder fuel is supplied from the mixing pipe into the primary combustion chamber, The air supply device for the hopper is operated at a predetermined time point to inject air from the injection nozzle for the hopper.

According to this control, in the fuel input step and the direct combustion step, the air supply device for the hopper can smoothly transfer the powder fuel in the fuel hopper to the fuel transfer device, so that the powder fuel can be stably supplied from the mixing pipe To the first combustion chamber.

[Effects of Invention] According to the present invention, it is possible to provide a combustion device and a combustion method which can burn well even if it is a powdered fuel such as a carbonized fuel using recycled synthetic resin or waste plastic as a raw material.

Next, an example of a powder fuel combustion device and a powder fuel combustion method of an embodiment of the present invention will be described with reference to FIGS. 1 to 3. Fig. 1 is an explanatory diagram of a power generation system equipped with a powder fuel combustion device of this embodiment. Fig. 2 is an explanatory diagram of the fuel supply device of the powder fuel combustion device of this embodiment. FIG. 3 is an explanatory diagram showing the structure of the bottom of the primary combustion chamber of the powder fuel combustion device of this embodiment. In this embodiment, the powdered fuel uses powdered char (char) made from waste plastic produced by the carbonized fuel production device described in Patent Document 2 as a raw material.

As shown in FIG. 1, the powder fuel combustion device 1 of the present embodiment is applied to a combustion device of a power generation system 2 using powder fuel F. In addition to the powder fuel combustion device 1, the power generation system 2 also includes a boiler 3, a dust collection device 4, a power generation device 5, a chimney 6, and a control device 7 for controlling these.

As shown in FIG. 1, the powder fuel combustion device 1 includes a fuel supply device 10, a primary combustion chamber 20, a secondary combustion chamber 50, an air supply ash discharge device 32, and a cyclone dust collector 60. The outlet of the cyclone dust collector 60 is connected to the boiler 3.

In this embodiment, the primary combustion chamber 20 has a cylindrical shape as a whole and is composed of a top 21 located above, a main body 22 located below the top 21, and a bottom 23 located below the main portion 22.

A primary exhaust port 24 is provided on the top 21 for exhausting combustible gas or combustion gas generated in the primary combustion chamber 20. In addition, a first temperature sensor 25 is provided at the primary exhaust port 24 to detect the temperature of the combustion gas generated in the primary combustion chamber 20. In addition, as shown in FIG. 1, the primary exhaust port 24 can be formed on the top plate of the top 21 or on the side surface of the top 21.

The fuel supply device 10 is connected to the main body 22. The fuel supply device 10 includes: a fuel hopper 11 for feeding powder fuel F; a mixing pipe 12 for mixing powder fuel F and combustion air; and a fuel delivery device 13 for feeding the fuel into the fuel. The powder fuel F of the hopper 11 is supplied to the mixing pipe 12 in an arbitrary supply amount; the fuel blower 14 is used to supply combustion air to the mixing pipe 12; and the burner port 15 is located at the front end of the mixing pipe 12.

At the center of the fuel hopper 11, an injection nozzle 16 for a hopper extending in the vertical direction and having a cylindrical shape is provided. The injection nozzle 16 for the hopper is a cylindrical element, which is open at the upper end and the lower end, and is provided with a plurality of injection ports 16a on the side surface to inject air. The lower end part of the injection nozzle 16 for a hopper is provided toward the opening part 11a of the hopper 11 for fuel. In addition, an air supply device 18 for a hopper composed of an air compressor 70, a solenoid valve 17 for fuel, and an air supply pipe 16b for fuel is connected to the injection nozzle 16 for a hopper.

The fuel transfer device 13 of the fuel supply device 10 transfers the powder fuel F by rotating the rotary valve 13b inside the cylindrical casing 13a. The fuel delivery amount per unit time is performed by adjusting the number of rotations of the rotary valve 13b by controlling a motor not shown in reverse phase.

The fuel blower 14 of the fuel supply device 10 also adjusts the air flow rate by controlling a motor (not shown) in reverse phase. The air-fuel ratio of the fuel blown out from the burner port 15 can be changed by adjusting the delivery amount of the powdered fuel F of the fuel delivery device 13 and the air flow rate of the fuel blower 14.

When the fuel supply device 10 is burning in the primary combustion chamber 20, when the powder fuel F and combustion air are supplied from the burner port 15 into the primary combustion chamber 20, the powder fuel F is in the burner port 15 It is ignited nearby and then burned as a burner.

In addition, a plurality of primary air supply ports 26 are provided on the peripheral wall of the main body 22 for supplying primary combustion air into the primary combustion chamber 20. Air is supplied to this primary air supply port 26 from a primary air blower 27 as a primary air supply device provided outside the main body 22.

In addition, a water vapor inlet 28 and a ventilation gas inlet 29 are provided at an upper position of the main body 22. If necessary, steam and ventilation gas can be introduced into the primary combustion chamber 20 from the inlets. For the water vapor, the water vapor containing odorous components recovered when the fuel is produced by the fuel production apparatus disclosed in Patent Document 2 can be used. The ventilation gas can be the gas recovered when the fuel production device disclosed in Patent Document 2 produces fuel.

In addition, the main body 22 is provided with an auxiliary burner 30 to assist combustion in the primary combustion chamber 20 and an auxiliary combustion solenoid valve 30 a to supply air to the auxiliary burner 30. In the auxiliary combustor 30, the ventilation oil or the like recovered when the fuel is produced by the fuel production apparatus disclosed in Patent Document 2 can be used as the fuel.

An inclined portion 23a is formed on the bottom 23 of the primary combustion chamber 20, which is inclined so as to narrow downward from the wall surface of the main body portion 22, and an ash discharge port 23b is formed below the inclined portion 23a. The inclined portion 23a is provided with a plurality of bottom air supply ports 31 for introducing combustion air into the inside. Air is supplied from the primary air blower 27 to the bottom air supply port 31.

In addition, the bottom 23 is provided with an air supply ash discharging device 32 located inside the inclined portion 23 a, and an ignition burner 33 for igniting the powder fuel F injected into the bottom 23. The fuel used by the ignition burner 33 is kerosene or heavy oil.

The air supply ash discharging device 32 includes a bottom air injection nozzle 34 and an ash conveying device 35. The bottom air injection nozzle 34 is a cylindrical element extending in the up and down direction, and is provided at the approximate center of the inclined portion 23a. The bottom air injection nozzle 34 is open at the upper end and the lower end, and a plurality of injection ports 34a are provided on the side surface to inject air. The lower end of the bottom air jet nozzle 34 is disposed toward the ash discharge port 23b.

As the jet air supply device 36, an air compressor 70, a bottom solenoid valve 37, and a bottom air supply pipe 38 are connected to the bottom air injection nozzle 34. The spray air is supplied from the spray air supply device 36 to the bottom air spray nozzle 34.

The ash transfer device 35 performs ash transfer by rotating the rotary valve 35b inside the cylindrical casing 35a. In addition, a sprinkling nozzle 39 is provided in the ash conveying device 35 for spraying water to the inside of the lower part of the housing 35a. When water is sprayed from the sprinkler nozzle 39, the ash in the housing 35a is cooled, and the ash is accumulated with water, so that it does not scatter around but falls downward.

An ash receiver 40 is arranged below the ash discharge port 23b, which can store the ash discharged from the ash discharge port 23b. The ash receiver 40 can be moved from the position below the ash discharge port 23b to the ash collection place by moving means such as a stacker.

The powder fuel combustion device 1 is additionally provided with a ventilation oil tank 71 and a water tank 72 for supplying ventilation oil as fuel to the auxiliary burner 30, and the water tank 72 for supplying water to the sprinkler nozzle 39.

The secondary combustion chamber 50 is a cylindrical combustion chamber, and is connected with a primary exhaust port 24 for introducing the combustion gas of the primary combustion chamber 20. A secondary burner 51 is provided near the connection portion of the primary exhaust port 24 to ignite the combustion gas. In addition, a plurality of secondary air supply ports 52 are provided on the peripheral wall of the secondary combustion chamber 50 to supply air for secondary combustion for secondary combustion. Air is supplied to this secondary air supply port 52 from a secondary air blower 53 as a secondary air supply device.

A secondary exhaust port 54 is provided on the downstream side of the secondary combustion chamber 50 and is connected to the cyclone dust collector 60. The secondary exhaust port 54 is provided with a second temperature sensor 55 for detecting the temperature of the combustion gas in the secondary combustion chamber 50. In addition, a recovery device 61 for the cyclone is provided below the cyclone dust collector 60.

The cyclone recovery device 61 is composed of a rotary valve 62 and a screw conveyor 63. The dust collected by the cyclone dust collector 60 is sent back to the primary combustion chamber 20 by the cyclone collection device 61 again and burned.

The boiler 3 of the power generation system 2 of the present embodiment is a device that generates superheated steam and saturated steam using the heat of the exhaust gas collected by the cyclone dust collector 60. In this embodiment, the boiler 3 performs heat recovery from exhaust gas at approximately 600°C, and reduces the outlet temperature of the exhaust gas to approximately 200°C.

The power generation device 5 is a device that generates power by rotating a turbine (not shown) by the steam generated by the boiler 3. The power generating device 5 adopts a device commonly used now. In this way, the steam generated by the boiler 3 can be used in addition to the power generation device 5, and can also be used in auxiliary equipment such as heating equipment.

A dust collector 4 is installed on the downstream side of the boiler 3. As the dust collecting device 4, a bag filter etc. which are generally and widely used can be used. In addition, a device for lowering the gas temperature is also arranged in front of the bag filter as necessary. In addition, the dust collecting device 4 may also adopt other dust collecting devices such as a centrifugal dust collector, an electric dust collector, or a gravity dust collector. In addition, depending on the scale of the power generation system 2 or the type of fuel for combustion, the dust collecting device 4 itself may be omitted.

A suction fan (not shown) is installed in the chimney 6, and the exhaust gas generated by the powder fuel combustion device 1 is sucked into the chimney 6 and discharged to the outside. The suction fan is also driven by reverse phase control, and the number of rotations is controlled by the signal of the control device 7.

The control device 7 is called a so-called control panel, and has built-in various operation switches, a display for displaying the operating status of each device, and a computer for controlling each device (not shown respectively). The computer of the control device 7 includes a CPU, a memory device, a communication device, etc. (not shown), and a program is stored in the memory device to execute the operation of the power generation system 2 including the powder fuel combustion device 1 of this embodiment.

Next, the combustion method of the powder fuel combustion device 1 of this embodiment will be described. The combustion method of this embodiment is composed of a fuel injection step, an ignition step, a gasification combustion step, a direct combustion step, and an embers and ashing step. These steps are executed by the program stored in the control device 7.

In the combustion method of this embodiment, the fuel injection step is first performed. In the fuel injection step, the fuel supply device 10 is used to deposit a predetermined amount of the powdered fuel F in the primary combustion chamber 20. The amount of the powder fuel F is set to such an extent that about 1/3 of the volume of the primary combustion chamber 20 is buried. If the operating efficiency of the powder fuel combustion device 1 is to be considered, the predetermined amount is preferably about 1/4 to 1/2 of the primary combustion chamber 20, but it can be appropriately changed according to the properties of the powder fuel F.

In this fuel injection step, first, the fuel supply device 10 is activated in a state where the powdered fuel F is injected into the fuel hopper 11 of the fuel supply device 10. Such input of the powder fuel F into the fuel hopper 11 can be controlled by the control device 7 using a conveyor or the like, or can be performed by manually operating a conveyor or the like.

When the fuel supply device 10 is activated by the control device 7, the rotary valve 13b rotates, and the powdered fuel F in the fuel hopper 11 is transferred to the bottom of the casing 13a through the rotary valve 13b. At this time, in the fuel hopper 11, the injection air is sent from the hopper air supply device 18 to the hopper injection nozzle 16 at a predetermined time. Thereby, the powdered fuel F in the fuel hopper 11 does not cause a bridge or the like, and is transported to the bottom of the casing 13a by the rotary valve 13b.

The time point at which the air supply device 18 for the hopper is activated can be appropriately changed according to the state of the powder fuel F. For example, the air supply device 18 for the hopper can be activated every 1 to 10 minutes, or every time the powder fuel F is activated. When adding to the fuel hopper 11, the hopper air supply device 18 is activated.

On the other hand, the operation of the fuel blower 14 is also started, and air is supplied to the mixing pipe 12. Thereby, the powdered fuel F and the supplied air are mixed in the inside of the mixing pipe 12 and discharged forward from the burner port 15.

At this time, since the ignition burner 33 and the auxiliary burner 30 are not activated in the primary combustion chamber 20, the powder fuel F discharged from the fuel supply device 10 is deposited on the bottom 23 of the primary combustion chamber 20. The operation of the fuel supply device 10 continues until approximately 1/3 of the volume of the primary combustion chamber 20 is buried, and after the powder fuel F is supplied until a predetermined amount is reached, the operation of the fuel supply device 10 is stopped.

In the combustion method of this embodiment, the ignition step is performed next. In the ignition step, first, combustion of the secondary combustor 51 in the secondary combustion chamber 50 is started to increase the temperature in the secondary combustion chamber 50. After the temperature of the secondary combustion chamber 50 reaches a predetermined temperature (800° C., etc.), the ignition burner 33 is activated to ignite the powder fuel F deposited in the primary combustion chamber 20. At this time, when the first temperature sensor 25 confirms that the powder fuel F deposited in the primary combustion chamber 20 is ignited, the ignition burner 33 is stopped.

Next, the gasification combustion step will be described. In the gasification combustion step, combustible gas is generated by burning part of the powder fuel F injected in the fuel injection step in the primary combustion chamber 20. The primary combustion air is supplied to the primary combustion chamber 20 from the primary air blower 27, the primary air supply port 26, and the bottom air supply port 31.

In the gasification combustion step, the primary combustion air introduced into the primary combustion chamber 20 is supplied with an air amount less than the air amount required to completely combust the powder fuel F. Therefore, a part of the powder fuel F is burned in the primary combustion chamber 20 to heat the surrounding powder fuel F and gradually expand the combustion range, thereby generating combustible gas from the powder fuel F.

At this time, air is intermittently supplied into the primary combustion chamber 20 from the bottom air injection nozzle 34 of the air supply ash discharge device 32. From the bottom air injection nozzle 34, air is injected from the upper and lower ends and the injection port 34a. At this time, for example, the injection is performed with a small amount of air for a predetermined time, and the injection amount is controlled to gradually increase the injection amount periodically or irregularly. Specifically, the powder fuel F around the bottom air injection nozzle 34 is sprayed at an amount that does not move by wind pressure for 5 minutes, and the strength of the powder fuel F around the bottom air injection nozzle 34 is stirred every 5 minutes. Jet air.

Alternatively, not only regular injection such as every 5 minutes, but also air injection in the following way: usually inject air at a relatively weak wind pressure, and when the temperature in the primary combustion chamber 20 reaches a predetermined temperature or lower, the powder fuel F is stirred The intensity of jetting air. By injecting air intermittently from the upper and lower openings of the bottom air injection nozzle 34 and the injection port 34a provided on the side surface, the powdered fuel F deposited on the bottom 23 of the primary combustion chamber 20 is stirred to perform good combustion.

In the gasification combustion step, when the combustible gas from the primary combustion chamber 20 is discharged into the heated secondary combustion chamber 50, the combustible gas is ignited by the secondary burner 51, and complete combustion is performed in the secondary combustion chamber 50 .

In this embodiment, the combustion temperature in the secondary combustion chamber 50 is controlled to be 800°C or higher, preferably 900°C or higher. In addition, when the temperature detected by the second temperature sensor reaches a predetermined temperature or higher, although the operation of the secondary burner 51 is stopped, the combustible gas from the primary combustion chamber 20 continues to flow in the secondary combustion chamber 50 thereafter. combustion.

In this gasification combustion step, the control device 7 controls the combustion temperature in the secondary combustion chamber 50 to be substantially constant. Regarding the control of the combustion temperature in the secondary combustion chamber 50, the secondary air blower 53 supplies the secondary air in a certain amount required for complete combustion of the combustible gas, and the primary air blower 27 Adjust the amount of air once.

In addition, at this time, the combustion temperature in the secondary combustion chamber 50 may also be controlled by controlling the combustion of the auxiliary combustor 30. On the other hand, even if the water vapor inlet 28 supplies water vapor and the ventilation gas inlet 29 introduces ventilation gas, the primary air blower 27 can adjust the amount of primary air to control the combustion temperature in the secondary combustion chamber 50.

The exhaust gas after complete combustion in the secondary combustion chamber 50 is discharged from the secondary exhaust port 54 and introduced into the boiler 3 via the cyclone dust collector 60. The cyclone dust collector 60 separates the dust in the exhaust gas and makes it fall to the bottom of the cyclone dust collector 60. The dust falling to the bottom in this manner is returned to the primary combustion chamber 20 by the rotary valve 62 of the cyclone recovery device 61 and the screw conveyor 63 to be burned.

Although the exhaust gas from which the dust is removed is high in the secondary exhaust port 54, the temperature is lowered by the heat exchange of the boiler 3 and is released to the outside air through the dust collector 4 and the chimney 6.

The boiler 3 uses the heat of the exhaust gas after combustion to generate steam, and the power generation device 5 uses the steam to generate electricity. In this embodiment, the powdered fuel F uses charcoal made from recycled plastic produced by a carbonized fuel production device described in Patent Document 2 as a raw material. In this way, in the power generation device 5, the powdered fuel F as a fuel uses the recycled plastic as a raw material, and the recycled plastic is used to generate electricity. Therefore, it is possible to generate electricity with a very small environmental load.

When the gasification and combustion step continues for a predetermined time, the powder fuel F deposited in the primary combustion chamber 20 gradually changes from gasification combustion to direct combustion. The transition of this combustion state is judged according to the temperature in the primary combustion chamber 20 and the temperature in the secondary combustion chamber 50.

Specifically, in a state where the temperature in the primary combustion chamber 20 maintains the status quo or an upward trend, the gradual transition from gasification combustion to direct combustion is detected when the temperature in the secondary combustion chamber 50 starts to decrease. Under the control of the control device 7, the primary air blower 27 adjusts the amount of primary air so that the combustion temperature in the secondary combustion chamber 50 is fixed.

As the powder fuel F in the primary combustion chamber 20 continues to burn, the powder fuel F gradually decreases, so the control device 7 controls to increase the number of rotations of the primary air blower 27 to increase combustible gas. As this state progresses, the reduced amount of powder fuel F in the primary combustion chamber 20 and the increased amount of primary air approach an appropriate air-fuel ratio, thereby approaching complete combustion, making the fuel supplied to the secondary combustion chamber 50 combustible The amount of the gas is reduced, and the temperature in the secondary combustion chamber 50 starts to decrease. When the temperature drop in the secondary combustion chamber 50 is detected in this way, the control device 7 determines that the combustion state has been switched.

In the combustion method of this embodiment, at the end of the gasification combustion step, it is switched to the direct combustion step. In the direct combustion step, the powder fuel F deposited on the bottom 23 of the primary combustion chamber 20 is continuously burned by direct combustion. At this time, air is supplied from the bottom air supply port 31, and air is also sprayed from the bottom air spray nozzle 34 intermittently.

In addition, in the direct combustion step, the powder fuel F is supplied from the fuel supply device 10. When the powder fuel F is supplied from the fuel supply device 10, since the primary combustion chamber 20 is in a state exceeding the ignition temperature of the powder fuel F, the powder fuel F injected from the burner port 15 is ignited, thereby continuously burning. In this way, in the direct combustion step, the fuel supply device 10 as a burner for powder fuel is operated.

The powder fuel F injected from the fuel supply device 10 is burned in this way while being supplied into the primary combustion chamber 20, the burned components are discharged as combustion gas to the secondary combustion chamber 50, and the unburned part is in the primary combustion chamber. Burn while depositing within 20. In addition, the powder fuel F supplied into the primary combustion chamber 20 is continuously burned by the combustion air supplied from the primary air supply port 26 and the bottom air injection nozzle 34, and gradually ashes.

In the combustion method of the present embodiment, when the direct combustion step ends, it is switched to the embers and ashing step. When the direct combustion step ends, the supply of the powder fuel F from the fuel supply device 10 is stopped. Thereby, only the powder fuel F deposited on the bottom 23 of the primary combustion chamber 20 is combusted in the primary combustion chamber 20, thereby gradually turning from direct combustion to ember combustion. When the embers combustion continues, the powder fuel F is gradually ashed.

At this time, air injection from the bottom air injection nozzle 34 is stopped, and air is supplied only from the primary air supply port 26 and the bottom air supply port 31. In this way, by stopping the air injection from the bottom air injection nozzle 34, the exhaust gas discharged from the secondary combustion chamber 50 can be prevented from generating white smoke.

In the embers and ashing step, by turning the powdered fuel F into embers and burning, the remaining powdered fuel F is gradually ashed, and finally almost becomes ash. The ashing of the powdered fuel F in the primary combustion chamber 20 can use the first temperature sensor 25 to detect the temperature in the primary combustion chamber 20.

The ash of the ashed powder fuel F is transferred to the outside of the primary combustion chamber 20 by the ash transfer device 35 of the air supply ash discharge device 32. In the ash conveying device 35, the ash present in the bottom 23 of the primary combustion chamber 20 is discharged to the outside from the ash discharge port 23b by rotating the rotary valve 35b. At this time, air is sprayed from the bottom air spray nozzle 34 intermittently and strongly, and the ash deposited on the bottom 23 is smoothly discharged to the outside.

In the ash discharge port 23b, water is sprayed from the sprinkler nozzle 39 to lower the temperature of the ash in the housing 35a. At the same time, the ash accumulates with the water so that it does not scatter around but falls downward. An ash receiver 40 is arranged below the ash discharge port 23b, and accommodates the ash discharged from the ash discharge port 23b, and is transported to the ash collection place by a stacker or the like as necessary.

In this manner, the power generation system 2 provided with the powder fuel combustion device 1 of the present invention completely burns the powder fuel F by supplying primary air from the fixed bottom air injection nozzle 34 and the bottom air supply port 31. Therefore, there is no need to analyze the unburned portion as described in Patent Document 1, and there is no need to change the angle when the primary air is supplied.

In addition, in the powder fuel combustion device 1 of the present invention, since the bottom air injection nozzle 34 of the air supply ash discharge device 32 intermittently injects air to the powder fuel F at the bottom 23 of the primary combustion chamber 20, the powder The bulk fuel F does not deposit on the bottom of the furnace, but surely undergoes combustion and ashing, and is discharged to the outside of the primary combustion chamber 20. Therefore, the powder fuel combustion device 1 of the present invention can surely burn the powder fuel F, and the power generation device 5 and the like can efficiently recover energy.

1: Powder fuel combustion device 2: Power generation system 3: boiler 4: Dust collection device 5: Power generation device 6: Chimney 7: Control device 10: Fuel supply device 11: Fuel feed hopper 11a: opening 12: Mixing tube 13: Fuel delivery device 13a, 35a: shell 13b, 35b, 62: rotary valve 14: Blower for fuel 15: Burner port 16: Jet nozzle for feed hopper 16a: Jet port 16b: Air supply pipe for fuel 17: Solenoid valve for fuel 18: Air supply device for feed hopper 20: Primary combustion chamber 21: top 22: Main body 23: bottom 23a: Inclined part 23b: Ash discharge port 24: Primary exhaust port 25: The first temperature sensor 26: Primary air supply port 27: Blower for primary air 28: Water vapor inlet 29: Ventilation gas inlet 30: auxiliary burner 30a: Solenoid valve for auxiliary combustion 31: Bottom air supply port 32: Air supply ash discharge device 33: Ignition burner 34: bottom air jet nozzle 34a: Jet port 35: Ash conveyor 36: Jet air supply device 37: Solenoid valve for bottom 38: bottom air supply pipe 39: Sprinkler nozzle 40: gray receiver 50: Secondary combustion chamber 51: Secondary burner 52: Secondary air supply port 53: Blower for secondary air 54: Secondary exhaust port 55: The second temperature sensor 60: Cyclone Dust Collector 61: Recovery device for cyclone 63: Screw conveyor 70: Air compressor 71: Ventilated fuel tank 72: water tank F: Powder fuel

Fig. 1 is an explanatory diagram of a power generation system including the powder fuel combustion device of this embodiment. FIG. 2 is an explanatory diagram of the fuel supply device in the powder fuel combustion device of this embodiment. FIG. 3 is an explanatory diagram showing the structure of the bottom of the primary combustion chamber of the powder fuel combustion device of this embodiment.

1: Powder fuel combustion device

2: Power generation system

3: boiler

4: Dust collection device

5: Power generation device

6: Chimney

7: Control device

10: Fuel supply device

11: Fuel feed hopper

11a: opening

12: Mixing tube

13: Fuel delivery device

13a, 35a: shell

13b, 35b, 62: rotary valve

14: Blower for fuel

15: Burner port

16: Jet nozzle for feed hopper

16a: Jet port

16b: Air supply pipe for fuel

17: Solenoid valve for fuel

18: Air supply device for feed hopper

20: Primary combustion chamber

21: top

22: Main body

23: bottom

23a: Inclined part

23b: Ash discharge port

24: Primary exhaust port

25: The first temperature sensor

26: Primary air supply port

27: Blower for primary air

28: Water vapor inlet

29: Ventilation gas inlet

30: auxiliary burner

30a: Solenoid valve for auxiliary combustion

31: Bottom air supply port

32: Air supply ash discharge device

33: Ignition burner

34: bottom air jet nozzle

34a: Jet port

35: Ash conveyor

36: Jet air supply device

37: Solenoid valve for bottom

38: bottom air supply pipe

39: Sprinkler nozzle

40: gray receiver

50: Secondary combustion chamber

51: Secondary burner

52: Secondary air supply port

53: Blower for secondary air

54: Secondary exhaust port

55: The second temperature sensor

60: Cyclone Dust Collector

61: Recovery device for cyclone

63: Screw conveyor

70: Air compressor

71: Ventilated fuel tank

72: water tank

F: Powder fuel

Claims (8)

A powder fuel combustion device is a combustion device for burning powder fuel, characterized in that: The powder fuel combustion device includes: a primary combustion chamber for burning the powder fuel inside; and a secondary combustion chamber for burning combustion gas discharged from the primary combustion chamber; The primary combustion chamber is provided with: a fuel supply device to supply the powder fuel to the inside; a primary air supply port to supply air to the inside; and an ignition burner to ignite the powder fuel inside ； The bottom of the primary combustion chamber is provided with: an inclined part, which is inclined in a way that the bottom narrows in the past; a bottom air supply port for supplying air to the inside; an ash discharge port, located below the inclined part; and a bottom air injection The nozzle is cylindrical and arranged facing up and down, with openings at the upper and lower ends, and the lower end is set toward the ash discharge port, and is used to supply air to the inside; The secondary combustion chamber is provided with a secondary burner to heat the interior and ignite the combustion gas discharged from the primary combustion chamber; and a secondary air supply port to supply combustion air to the interior; The powder fuel combustion device is provided with: a primary air supply device for supplying air to the primary air supply port and the bottom air supply port; an injection air supply device for supplying air to the bottom air injection nozzle; secondary air supply A device for supplying air to the secondary air supply port; and a control device for controlling the fuel supply device, the ignition burner, the secondary burner, the primary air supply device, the injection air supply device, and The action of the secondary air supply device; The control device is: The fuel supply device is used to deposit a predetermined amount of the powdered fuel in the primary combustion chamber, The deposited powder fuel is ignited by the ignition burner, and the secondary burner is activated and the secondary combustion chamber is heated at the same time, When the deposited powder fuel is vaporized and burned, the primary air supply device and the injection air supply device are activated, and air is supplied from the primary air supply port, the bottom air supply port, and the bottom air injection nozzle. The amount of air is less than the amount of air required to completely burn the deposited powder fuel to generate combustible gas in the primary combustion chamber, When the deposited powder fuel is directly burned, the primary air supply device and the injection air supply device are activated, and the primary air supply port, the bottom air supply port, and the bottom air injection nozzle are used to The amount of air required for direct combustion of the powder fuel is supplied to the primary combustion chamber, and the fuel supply device is activated at the same time, and the powder fuel is supplied to the primary combustion chamber and burned, so that the fuel supply as a burner Device actuation, When the deposited powder fuel is vaporized and burned, and when the deposited powder fuel is directly burned, the secondary air supply device is activated, and the flammability is made from the secondary air supply port. The amount of air required for the complete combustion of the gas is supplied to the secondary combustion air to burn the combustible gas. The powder fuel combustion device according to claim 1, wherein when the powder fuel in the primary combustion chamber is burned and ashed, the fuel supply device is stopped and the bottom air injection nozzle is stopped. Supply air. The powder fuel combustion device according to claim 1 or 2, wherein, when the deposited powder fuel is vaporized and combusted, and when the deposited powder fuel is directly burned, the control device uses a regular Or the injection air supply device can be controlled irregularly so that the injection amount of the powder fuel can be stirred to inject air to the bottom air injection nozzle. The powder fuel combustion device according to any one of claims 1 to 3, wherein the fuel supply device has: a fuel hopper for inputting the powder fuel; and an injection nozzle for the fuel hopper; The inside of the hopper is arranged upward and downward and used to inject air at least downward; an air supply device for the hopper is used to supply air to the injection nozzle for the hopper; a fuel delivery device is installed below the injection nozzle for the hopper and Used for conveying the powder fuel downward; a mixing tube for mixing the powder fuel and air; and a fuel blower for supplying air to the mixing tube; The control device is configured such that when the powder fuel is supplied to the primary combustion chamber, the fuel blower can be activated, and the fuel delivery device can be activated, and the powder fuel and the fuel delivery device can be activated inside the mixing tube. The air supplied by the fuel blower is mixed, the powdered fuel is supplied from the mixing pipe into the primary combustion chamber, and the air supply device for the hopper is operated at a predetermined time to inject air from the injection nozzle for the hopper. A powder fuel combustion method is a combustion method that uses a powder fuel combustion device to burn a powder fuel, and is characterized in that: The combustion method consists of a fuel input step, an ignition step, a gasification combustion step, a direct combustion step, and an embers and ashing step; The powder fuel combustion device includes: a primary combustion chamber for burning the powder fuel inside; and a secondary combustion chamber for burning gas discharged from the primary combustion chamber; The primary combustion chamber is provided with: a fuel supply device to supply the powder fuel to the inside; a primary air supply port to supply air to the inside; and an ignition burner to ignite the powder fuel inside ； The bottom of the primary combustion chamber is provided with: an inclined part, which is inclined in a way that the bottom narrows in the past; a bottom air supply port for supplying air to the inside; an ash discharge port, which is provided below the inclined part; and a bottom air injection The nozzle is cylindrical and arranged facing up and down, with openings at the upper and lower ends, and the lower end is set toward the ash discharge port, and is used to supply air to the inside; The secondary combustion chamber is provided with: a secondary burner for heating the interior; and a secondary air supply port for supplying combustion air to the interior; The powder fuel combustion device is provided with: a primary air supply device for supplying air to the primary air supply port and the bottom air supply port; an injection air supply device for supplying air to the bottom air injection nozzle; secondary air supply A device for supplying air to the secondary air supply port; and a control device for controlling the fuel supply device, the ignition burner, the secondary burner, the primary air supply device, the injection air supply device, and The action of the secondary air supply device; With this control device, In the fuel input step, the fuel supply device is used to deposit a predetermined amount of the powdered fuel in the primary combustion chamber; In the ignition step, the secondary combustion chamber is heated by the secondary burner, and after the temperature of the secondary combustion chamber reaches a predetermined temperature, the deposited powder fuel is ignited by the ignition burner; In the gasification and combustion step, from the primary air supply port, the bottom air supply port, and the bottom air injection nozzle, the amount of air is less than the amount of air required to completely combust the deposited powder fuel. The combustible gas is generated in the primary combustion chamber, the combustible gas is introduced into the secondary combustion chamber, and the secondary combustion air is supplied from the secondary air supply port to completely burn the combustible gas; In the direct combustion step, the primary air supply device and the injection air supply device are activated, and the powder fuel is directly combusted from the primary air supply port, the bottom air supply port, and the bottom air injection nozzle The required amount of air is supplied into the primary combustion chamber, and the fuel supply device is activated at the same time, and the powdered fuel is supplied into the primary combustion chamber and burned, and the fuel supply device as a burner is activated and introduced from the The combustion gas discharged from the primary combustion chamber enters the secondary combustion chamber, and the secondary combustion air is supplied from the secondary air supply port to completely burn the combustion gas; In the embers and ashing step, the fuel supply from the fuel supply device is stopped, and the powdered fuel embers remaining in the primary combustion chamber are burned and ashed. The powder fuel combustion method according to claim 5, wherein in the embers and ashing step, the air supply from the bottom air injection nozzle is stopped. The method for burning a powder fuel according to claim 5 or 6, wherein, in the gasification and combustion step and in the direct combustion step, the control device is used to periodically or irregularly stir the powder fuel The spray amount sprays air to the bottom air spray nozzle to control the spray air supply device. The method for burning a powdered fuel according to any one of claims 5 to 7, wherein the fuel supply device has: a hopper for fuel for injecting the powdered fuel; an injection nozzle for the hopper for feeding the fuel The inside of the hopper is arranged upward and downward and used to inject air at least downward; an air supply device for the hopper is used to supply air to the injection nozzle for the hopper; a fuel delivery device is installed below the injection nozzle for the hopper and For conveying the powder fuel downward; a mixing pipe for mixing the powder fuel and air; and a fuel blower for supplying air to the mixing pipe, In the fuel input step and the direct combustion step, the fuel blower is activated by the control device, and the fuel delivery device is activated at the same time, and the powdered fuel and the fuel blower are operated in the mixing pipe. The supplied air is mixed, the powdered fuel is supplied from the mixing pipe into the primary combustion chamber, and the air supply device for the hopper is operated at a predetermined time point to inject air from the injection nozzle for the hopper.

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