JPH06101828A - Fluidized bed combustion furnace - Google Patents

Abstract

PURPOSE:To provide a device not requiring any heat resistance or cooling and having a high reliability at a low cost in equipment used in separating and transporting fluidized material discharged from a bottom part of a combustion furnace and foreign materials. CONSTITUTION:A foreign material separating part 123 is connected to a bottom part of the body 1 of a combustion furnace through a neumatic valve 122. A foreign material removing pipe 125 for use in discharging foreign materials and a particle transporting pipe 126 for circulating fluidized material into the main body 1 of the furnace are connected to an outlet of the separating part 123. A discharging conveyor 128 for discharging foreign materials is installed at a lower part of the foreign material separating part 123. There is provided a water tank 127 into which the foreign material removing pipe 125 is inserted. With such an arrangement as mentioned above, the conveyor requiring heat- resistance or cooling and a valve can be eliminated and it is possible to embody the device the operation of which can be easily performed at a low cost and under a high reliability.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circulating type or bubble type fluidized bed combustion furnace which uses industrial waste containing incombustibles as a fuel.

[0002]

2. Description of the Related Art FIG. 3 shows a structural example of a conventional bubbling type fluidized bed combustion furnace. A conventional bubbling type device will be described below with reference to FIG. In FIG. 3, a nozzle 2 is provided at the bottom of the furnace body 1.
Is attached to the eye plate and is fluidized by the air supplied from the blower 3. At the bottom of the furnace body 1, there is an L for further extracting foreign matter and fluid material from the furnace.
A structure called a pneumatic valve 4 having a V shape (an inverted L shape in FIG. 3) is provided. The outlet of the pneumatic valve 4 is connected to a particle carrying pipe 5, a foreign matter extracting pipe 6 and a foreign matter separating section 7.

Foreign matter accumulated at the bottom of the fluidized bed is removed by the blower 8
By supplying air supplied from the solenoid valve 9 intermittently or continuously, the air is discharged together with the fluid material into the foreign matter separating section 7, and the blower 8 separates the air line 10 for separation.
The foreign matter and the fluid material are separated by the air supplied via the.
The separated foreign matter passes through the foreign matter extracting pipe 6 and the hopper 11
Then, it is discharged to the outside of the apparatus by operating the valves 12a, 12b, 12c, 12d. The fluid material separated by the foreign matter separating unit 7 passes through the particle conveying pipe 5 by air flow conveyance and returns to the inside of the combustion furnace again.

Fuel is supplied from the fuel hopper 13 to the feeder 14
Is supplied to the furnace. Combustion gas is cyclone 1
5, convection heat transfer surface 16, bag filter 17, induction fan 1
The gas is emitted from the chimney 19 to the atmosphere via 8. The ash collects in the ash hopper 20 and is discharged to the outside of the system. The temperature of the combustion furnace is controlled by the heat transfer surface 21.

FIG. 4 shows an example of the construction of a conventional circulating type fluidized bed combustion furnace, and the conventional circulating type apparatus will be described below with reference to FIG. In FIG. 4, a pan having a nozzle 2 is attached to the bottom of the furnace body 1 and is fluidized by the air supplied from the blower 3.

At the bottom of the furnace body 1, there is further provided a water-cooled screw conveyor 104 for extracting foreign matter and fluidized material to the outside of the furnace. The outlet of the screw conveyor 104 is connected to the sieve 107 via the transfer conveyor 105 and the separation hopper 106, and the fluid material passing through the sieve 107 is recirculated into the furnace by the injector 108. The air for recirculation is supplied from the blower 109 and used as secondary air for combustion in the furnace body 1.

Fuel is supplied from the fuel hopper 110 to the feeder 1.
It is supplied into the furnace by 11. The combustion gas is discharged to the atmosphere from the chimney 116 through the cyclone 112, the convection heat transfer surface 113, the bag filter 114, and the induction fan 115.
Ash is collected in the ash hopper 117 and discharged to the outside of the system.

In the circulating fluidized bed combustion furnace, the fluidized state of the particles is in a state called a high speed fluidized bed, so that a large amount of fluidized material (particles) is ejected together with the gas. The particles that fly out together with the combustion gas are separated into gas and particles by the cyclone 112, and the particles are recirculated through the external heat exchanger 118 into the furnace. At that time, the particles are transferred to the heat transfer surface 1 in the heat exchanger 118.
Since the heat is removed by the heat transfer surface 19 and the heat transfer surface 120 to cool the heat transfer surface 120, the combustion temperature can be adjusted. The fluidizing air in the heat exchanger is supplied from the blower 121.

[0009]

The conventional device has the following problems. (1) Due to the high temperature of the fluidized material and the foreign matter extracted,
It is necessary to make the equipment have heat resistance or to cool it. In that case, it is necessary to use a high temperature material such as a valve. (2) Foreign matter may get caught in the conveyor or valve,
This may cause air tightness and damage the conveyor and valves. (3) Foreign matter is separated after cooling the fluid material,
Most of the heat that particles bring out is lost.

The present invention is intended to solve the above problems.

[0011]

The fluidized bed combustion furnace of the present invention is a pneumatic valve connected to the bottom of the furnace body and supplied with air, and a particle connected to the outlet of the valve and causing the fluid to flow back to the outlet. A foreign matter separating part provided with a carrier pipe and a foreign matter discharging pipe for discharging foreign matter, to which air is supplied, a water tank provided below the foreign matter separating part and having the foreign matter discharging pipe inserted therein, and arranged in the water tank It is characterized by having a discharge conveyor.

[0012]

In the above, during normal operation, air is supplied only to the foreign matter separating section, and this air is supplied into the furnace body through the foreign matter separating section and the particle conveying pipe.

When foreign matter is generated and is taken out, air is also supplied to the pneumatic valve. When air is supplied to the pneumatic valve, the mixture of the foreign matter and the fluid material enters the foreign matter separating section, and the foreign matter and the fluid material are separated by the air flowing through the foreign matter separating section. It settles inside and is discharged outside by a discharge conveyor. Further, the fluid material is returned to the inside of the furnace body again through the particle conveying pipe.

Since the foreign matter extracting pipe is inserted into a water tank filled with water and the lower end is closed by water, a constant pressure is maintained in the foreign matter separating portion and the flow velocity of each portion. Therefore, the fluid material and the foreign matter are properly separated in the foreign matter separating section, and the fluid material is favorably conveyed in the particle conveying pipe and the foreign matter is favorably conveyed in the foreign substance extracting pipe.

Further, since the foreign matter having passed through the foreign matter extracting pipe once settles in the water tank and is cooled by water,
The discharge conveyor for discharging foreign matter from the water tank to the outside does not need heat resistance.

As described above, it is not necessary to use a conveyor or a valve which requires heat resistance and cooling as in the conventional apparatus, and a low cost, highly reliable and easy operation apparatus is realized.

[0017]

FIG. 1 shows a first embodiment of the present invention. In the present embodiment shown in FIG. 1, heat transfer surfaces 119 and 120 are provided in a heat exchanger 118 below a furnace body 1, and a plate having a nozzle 2 is arranged at the bottom of the heat transfer surfaces 119 and 120. The supplied air fluidizes the inside of the furnace body 1, and the fuel hopper 1 is connected to the side portion of the furnace body 1 via a feeder 111.
The fuel is supplied from 10, and a part of the fluid material (particles) and the combustion gas are discharged into the cyclone 112 provided in the upper part of the furnace body 1, and the fluid material connects the bottom of the cyclone 112 and the bottom of the furnace body 1. The circulating fluidized bed is recirculated into the furnace body 1 by the recirculation pipe 112a, and the combustion gas is discharged to the outside through the convection heat transfer surface 113 having the ash hopper 117, the bag filter 114, the induction fan 115 and the chimney 116. In the combustion furnace, an inverted L-shaped pneumatic valve 122 connected to the bottom of the furnace body 1, a foreign matter separating portion 123 connected to the outlet of the pneumatic valve 122, and an outlet of the foreign matter separating portion 123 are connected. Foreign matter extraction tube 12
5, a water tank 127 into which the foreign matter extracting pipe 125 is inserted and is disposed below the foreign matter separating section 123, a carry-out conveyor 128 provided in the water tank 127, and one end of which is connected to the outlet of the foreign matter separating section 123 And the other end is the furnace body 1
And a blower 109 connected to the pneumatic valve 122 by a pipe via an electromagnetic valve 124 and to the foreign matter separating unit 123 by a pipe.

In the above, the system except the part relating to the foreign matter separating mechanism is the same as the conventional device described above.
Therefore, here, the operation when foreign matter is accumulated in the combustion furnace due to continuous operation will be described.

First, when operating steadily, the solenoid valve 124 is closed, so that the air from the blower 109 is entirely in the foreign matter separating portion 123 and the particle conveying pipe 1.
It is supplied into the furnace body 1 through 26 and is used as secondary air for combustion. At this time, the pressure at the outlet of the pneumatic valve 122 is higher than the pressure of the atmosphere and is about 2000 to 3000 mm of water column.

The foreign matter extracting pipe 125 is inserted into a water tank 127 filled with water 129 and holds the above pressure by the liquid pressure of water. Therefore, the height of the water surface inside the foreign matter extraction pipe 125 and the water surface height of the water tank 127 have a difference corresponding to the pressure.

Next, an operation for extracting the generated foreign matter will be described. The solenoid valve 124 is opened while the flow rate of the blower 109 is kept constant, and the pneumatic valve 12 is opened.
Pour air to the bottom of 2. By this operation, the mixture of the foreign matter and the fluid material enters the foreign matter separating section 123, and the foreign matter separating section 123
The foreign matter and the fluid material are separated by the air flowing through the foreign matter, the foreign matter settles in the water tank 127 through the foreign matter extraction pipe 125, and the fluid material returns to the furnace again. In this operation, the flow velocity of each part is selected as follows.

At the outlet of the pneumatic valve 122, when the solenoid valve 124 is opened and closed intermittently, about 1 m / s, when continuously opened, about 2 m / s, the foreign matter separating portion 123.
Is about 4 times the fluidization start speed to the terminal end velocity of the particles, and in the particle transport pipe 126 is about twice or more the terminal end velocity of the particles.

Since the water tank 27 is open to the atmosphere and the temperature of the extracted foreign matter is low,
Foreign substances can be easily taken out by the discharge conveyor 128.

According to the above, the foreign matter is taken out by the conveyor after being cooled in the water tank, and the conveyor does not come into contact with the high temperature fluid material and the foreign matter. Therefore, the cost for improving the heat resistance of the conveyor becomes unnecessary, and It has become possible to reduce the cost and improve the reliability of the device.

A second embodiment of the present invention is shown in FIG. In the present embodiment shown in FIG. 2, a perforated plate having a nozzle 2 is arranged at the bottom of the furnace body 1, and the air supplied from the blower 3 fluidizes the inside of the furnace body 1 to the side of the furnace body 1. Feeder 14
Fuel is supplied from the fuel hopper 13 connected via the, the combustion gas is introduced into the cyclone 15 connected to the upper part of the furnace body 1, the convection heat transfer surface 16, the bag filter 17,
The ash in the combustion gas discharged to the outside through the induction fan 18 and the chimney 19 is the cyclone 15 and the convection heat transfer surface 16 described above.
From the ash hopper 20 to the outlet of the pneumatic valve 4 connected to the bottom of the furnace body 1 and the foreign matter separating portion 7
, The fluid material (particles) separated by the foreign matter separating section 7 by the air supplied from the blower 8 via the solenoid valve returns to the inside of the furnace main body 1 via the particle conveying pipe 5, and the foreign matter extracting pipe In the bubble type fluidized bed combustion furnace discharged from No. 6,
A water tank 22 provided below the foreign matter separating unit 7 and into which the foreign matter extracting pipe 6 is inserted, and a discharge conveyor 23 provided in the water tank 22 are provided.

In the above, the system except the part relating to the foreign matter separating mechanism is the same as the conventional device described above.
Therefore, here, the operation when foreign matter is accumulated in the combustion furnace due to continuous operation will be described.

First, when operating steadily, the solenoid valve 9 is closed, so that the air from the blower 8 is entirely supplied to the combustion furnace through the foreign matter separating section 7 and the particle conveying pipe 5. , Used as secondary air for combustion.
At this time, the pressure at the outlet of the pneumatic valve 4 is higher than the pressure of the atmosphere and is about 2000 to 3000 mm of water column.

The foreign matter extracting pipe 6 is inserted into a water tank 22 filled with water 24, and the pressure in the foreign matter extracting pipe 6 is held by the liquid pressure of water. Therefore, the height of the water surface inside the foreign matter extraction pipe 6 and the water tank 2
The water surface height of 2 has a difference corresponding to the pressure.

Next, an operation for extracting the generated foreign matter will be described. The solenoid valve 9 is opened while keeping the flow rate of the blower 8 constant, and air is allowed to flow through the pneumatic valve 4. By this operation, the mixture of the foreign matter and the fluid material enters the foreign matter separating section 7, and the foreign matter and the fluid material are separated by the air flowing in the foreign matter separating section 7, and the foreign matter settles in the water tank 22 through the foreign matter extracting pipe 6. , The fluid material returns to the furnace again. In this operation, the flow velocity of each part is selected as follows.

A solenoid valve 9 is provided at the outlet of the pneumatic valve 4.
When opening and closing intermittently, it is about the fluidization start speed, when it is continuously opened, it is about twice the fluidization start speed, and in the foreign matter separating section 7 four times the fluidization start speed to the end velocity of particles. In the particle conveying pipe 5, it is about twice or more the terminal velocity of particles.

Since the water tank 22 is open to the atmosphere and the temperature of the extracted foreign matter is low, the foreign matter can be easily taken out by the discharge conveyor 23.

According to the above, the foreign matter is cooled in the water tank and then taken out by the conveyor, and the valve does not come into contact with the high temperature fluid material or foreign matter. Therefore, the cost for improving the heat resistance of the valve becomes unnecessary, and It has become possible to reduce the cost and improve the reliability of the device.

[0033]

In the fluidized bed combustion furnace of the present invention, the foreign matter separating portion is connected to the bottom of the furnace body through the pneumatic valve,
At the outlet of the separating unit, a particle conveying pipe for circulating the fluid material into the furnace body and a foreign substance extracting pipe for discharging foreign substances are connected, and a discharging conveyer for discharging foreign substances is provided below the foreign substance separating unit. By providing a water tank in which the foreign substance extraction pipe is inserted, it is not necessary to use a conveyor or a valve that requires heat resistance and cooling unlike the conventional device, and a device that is low cost, highly reliable, and easy to operate To be realized.

[Brief description of drawings]

FIG. 1 is an explanatory view of a circulating fluidized bed combustion furnace according to a first embodiment of the present invention.

FIG. 2 is an explanatory view of a bubble type fluidized bed combustion furnace according to a second embodiment of the present invention.

FIG. 3 is an explanatory view of a conventional bubbling type fluidized bed combustion furnace.

FIG. 4 is an explanatory diagram of a conventional circulating fluidized bed combustion furnace.

[Explanation of symbols]

 1 Furnace Main Body 2 Nozzle 3 Blower 4 Pneumatic Valve 5 Particle Transfer Pipe 6 Foreign Material Extraction Pipe 7 Foreign Material Separation Section 8 Blower 9 Electromagnetic Valve 21 Heat Transfer Surface 22 Water Tank 23 Discharge Conveyor 24 Water 109 Blower 118 Heat Exchanger 119, 120 Transmission Heat surface 121 Blower 122 Pneumatic valve 123 Foreign matter separation section 124 Electromagnetic valve 125 Foreign matter extraction pipe 126 Particle transfer pipe 127 Water tank 128 Discharge conveyor 129 Water

Claims (1)

[Claims] 1. A pneumatic valve, which is connected to the bottom of the furnace body and is supplied with air, is provided with an outlet of the valve, which is provided with a particle conveying pipe for refluxing a fluid material and a foreign matter extracting pipe for discharging foreign matter. A flow characterized by comprising a foreign matter separating unit to which air is supplied, a water tank provided below the foreign matter separating unit, into which the foreign matter extracting pipe is inserted, and a discharge conveyor arranged in the water tank. Layer combustion furnace.