JPH04155114A - Fluidized bed incinerator and operation thereof - Google Patents

Abstract

PURPOSE:To perform smooth take-out of a non-combustible substance and to perform effective recovery of heat by a method wherein a partition wall is located in a direction extending at 90 deg. with a non-combustible substance take-out port, a heat exchanger is arranged in the partition wall, and a nozzle is mounted on a furnace floor surface. CONSTITUTION:Refuse 15 is dropped from a dust feeding device 16 to a fluidized bed part 2 for combustion. A partition wall 7 is built at the one side of the periphery of a fluidized bed part 2 in a direction extending at 90 deg. with a non-combustible substance take-out port 6. A heat exchanger 9 is located at the interior 8 of a partition wall between the partition wall 7 and a furnace wall, and a quantity of heat is recovered from fluidized sand. A quantity of a recovered heat is influenced by an amount of sand circulating through the interior 8 of the partition wall, the heat exchanger 9, and the heat transfer factor of the circulating sand. An amount of circulating sand is changed in a way that a nozzle is mounted on a furnace floor surface separably from the nozzle of a main fluidized air 11 and a quantity of air 12 circulating through a heat exchange part is regulated through opening and closing a valve 19 by means of an air amount controller 18. The factor heat transfer between the heat exchanger 9 and the circulating sand is changed in a way that a nozzle is arranged on a furnace floor surface and a quantity of heat exchange part air 13 is regulated through opening and closing of a valve 20. This constitution holds a furnace floor temperature at a constant value, effects effective recovery of heat, and performs smooth take-out of a noncombustible substance.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fluidized bed incinerator, and particularly to a fluidized bed incinerator that can effectively recover heat from the hearth and a method of operating the same.

[Conventional technology]

BACKGROUND ART In recent years, incineration of materials to be combusted, including non-combustible materials such as municipal waste, in a fluidized bed furnace has become very popular. The reason for this is that the incineration residue of the fluidized bed furnace is dry and completely combusted. Methods for discharging incombustibles in fluidized bed furnaces can be roughly divided into two methods: one is to move the incombustibles to the incombustibles discharge port by tilting the hearth, and the other is to move the incombustibles by swirling the sand in the fluidized bed. FIG. 3 shows an incinerator in which incombustible materials are moved by swirling sand in a fluidized bed.

In the figure, 1 is a hearth 2 is a fluidized bed, 3 is a deflector,
4 is a fluidized bed part a, 5 is a fluidized bed part port, and 6 is a noncombustible material discharge port.

Creating a difference in the superficial velocity between the fluidized bed section A and the fluidized bed section inlet;
When the fluid medium is reversed by the deflector, the fluid medium turns, and the noncombustible material is moved to the noncombustible material discharge port by the force of the fluid medium.

In addition, in fluidized bed incinerators for municipal waste, industrial waste, etc., recovery of exhaust heat from the hearth is important. The hearth temperature is controlled at 800 degrees or less to prevent the fluidized medium from melting. Currently, this is controlled by spraying water on the hearth, but if heat is recovered using a waste heat boiler, water spraying is not desirable as it reduces the amount of evaporation. Heat recovery from the hearth was awaited. Various methods of recovering heat from the fluidized bed have been proposed. When dealing with municipal waste and industrial waste, the installation method of the heat exchanger is not suitable, and there are restrictions due to the shape of the combustible material removal port, making it difficult to achieve both smooth removal of non-combustible material5, and so on. There are few examples.

As a publicly known example of these techniques, JP-A-62-272
There is a heat recovery method from a fluidized bed and its apparatus described in Japanese Patent No. 089, and an internal circulation fluidized boiler and its control method described in PCT/J P 87100530. However, even in these known examples, if noncombustible materials are included in the materials to be combusted,
In a device that moves noncombustibles by swirling sand in a fluidized bed, the swirling of the fluidized medium is also used to move the fluidized medium to the heat recovery section, so the movement speed of the noncombustibles and the amount of heat recovered can be controlled individually. difficult to do. In addition, the PCT/J
In the internal circulation type fluid boiler and its control method described in P87100530, the optimum height and shape of the deflector for extracting incombustibles, the position for extracting incombustibles, etc. are constrained by the shape of the heat recovery section, and the optimal shape cannot be determined. It is not possible to do so.

[Problem to be solved by the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a fluidized bed incinerator and a method for operating the same that can solve the above-mentioned problems, smoothly take out incombustibles, and efficiently recover heat.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a fluidized bed incinerator that incinerates the incombustible material and moves the noncombustible material to the noncombustible material outlet by swirling the fluidized medium by main flowing air. A partition wall is provided on at least one side of the periphery of the fluidized bed section in the direction of , a heat exchanger or a boiler is provided inside the partition wall, and the flow rate can be controlled separately from the main fluidizing air nozzle on the hearth surface in front of the partition wall. This fluidized bed incinerator is characterized by installing a nozzle, and in this fluidized bed incinerator, the hearth surface between the partition wall and the furnace wall further includes:
It is preferable to install a nozzle that can control the flow rate separately from the main flow air nozzle.

In addition, in order to achieve the objective of the above-mentioned function, in the present invention, the incombustible material is incinerated, the noncombustible material is moved to the noncombustible material outlet by swirling the fluidized medium by the main flowing air, and the noncombustible material is moved to the noncombustible material outlet and 9.
In operation of a fluidized bed incinerator in which a partition wall is provided on at least one side of the periphery of the fluidized bed section in the 0 degree direction, and a heat exchanger or boiler is provided inside the partition wall, the hearth surface in front of the partition wall, the partition wall, and the furnace wall. By installing nozzles that can control the flow rate separately from the main flow air nozzles on the hearth surface between This is a method of operating a fluidized bed incinerator, which is characterized by controlling the temperature of the hearth and keeping the hearth temperature constant.

That is, the present invention provides a fluidized bed incinerator that incinerates incineration materials containing noncombustible materials such as municipal waste and industrial waste, and moves the noncombustible materials to a noncombustible material extraction port by swirling a fluidized medium. The heat exchanger or boiler for waste heat recovery should be placed sufficiently away from the center of the fluidized bed where waste falls, and a partition wall should be installed on at least one side of the periphery of the fluidized bed in a direction 90 degrees from the incombustible material outlet. The lower and upper parts of the bulkhead are cut out to allow the movement of fluidized sand, and the fluidized bed inside the bulkhead between the bulkhead and the furnace wall is installed inside the sloped bulkhead, and the main fluidized air is placed on the hearth surface in front of the bulkhead. Installing a nozzle that can control the flow rate separately from the nozzle to increase or decrease the amount of circulating air in the heat exchange section supplied from there, and a nozzle for main flow air on the hearth surface between the partition wall and the furnace wall. A nozzle that can separately control the flow rate is installed, and the amount of heat exchanged is adjusted by increasing or decreasing the amount of air supplied from the nozzle, and the hearth temperature is controlled to be kept constant.

[Effect]

When garbage falls into the fluidized bed and burns, part of the combustion heat is transferred to the fluidized sand, increasing its temperature. The fluidized bed section is filled with fluidized sand (fluidized medium).

A partition wall is installed on one side of the periphery of the fluidized bed section, which is far enough away from the center of the fluidized bed section where waste falls, and the lower and upper parts of the partition wall are cut out to allow fluidized sand to move. If a heat exchange section is provided inside the partition wall between the two, heat can be recovered from the fluidized sand. The amount of heat recovered depends on the amount of sand circulating inside the partition wall and the heat transfer coefficient of the heat exchanger and the amount of circulation. When the amount of sand circulation is large, the amount of heat exchange is large, and when the heat transfer coefficient between the heat exchanger and the amount of circulation is large, the amount of heat exchange is large.

Keeping the hearth temperature constant is by varying these two variables. The amount of sand circulating inside the partition wall can be controlled by installing a nozzle that can control the flow rate separately from the main flowing air nozzle on the hearth surface in front of the partition wall, and controlling the amount of circulating air in the heat exchange section supplied from there. Change by increasing or decreasing. Sand circulation is caused by the difference between the amount of air in front of the bulkhead and the flow rate inside the bulkhead. Therefore, when increasing the amount of circulation, the difference in flow rate with the amount of air inside the partition wall is increased, and when reducing the amount of circulation, the difference in flow rate with the amount of air inside the partition wall is reduced.

The heat transfer coefficient of the heat exchanger and circulation rate can be determined by installing a nozzle that can control the flow rate separately from the main flow air nozzle on the hearth surface between the partition wall and the furnace wall. It is changed by increasing or decreasing the amount of air in the exchange section. The amount of air in the heat exchange section changes the range in which the inside of the partition wall changes from a fixed bed to a fluidized bed, and utilizes the fact that, as is generally known, the heat transfer coefficient changes rapidly during this period. The fluidized bed inside the partition wall is sloped to allow fluidized sand to circulate. In a rectangular furnace, by providing a partition wall in a direction 90 degrees from the incombustible material outlet, there is no restriction on the shape of the incombustible material outlet.

〔Example〕

Hereinafter, the present invention will be specifically explained with reference to the drawings, but the present invention is not limited thereto.

Example 1 FIG. 1 is a plan view of the hearth of a fluidized bed incinerator showing an example of the present invention, and FIG. 2 is a plan view of the hearth of the fluidized bed incinerator shown in FIG. 1.
FIG. FIG. 3 shows a sectional view taken along the line AA in FIG. 1, and this sectional view is the same as that of a conventional fluidized bed incinerator.

In the figure, 1 is the hearth, 2 is the fluidized bed, 3 is the deflector, 4 is the fluidized bed part A, 5 is the fluidized bed part mouth, 6 is the incombustible material outlet, 7 is the partition wall, 8 is inside the partition wall, 9 is the heat exchanger Exchanger, 10 is a wind box, 11.11' is fluidized air, 12 is heat exchange section circulating air,
13 indicates heat exchange section air.

As shown in the figure, a partition wall 7 is provided in a direction 90 degrees from the incombustible material outlet 6, and a heat exchanger 9 is installed inside the partition wall 7. As shown in FIG. 2, on the hearth surface 1,
Separately from the flowing air 11, nozzles for heat exchanger circulation air 12 and heat exchanger air 13 are provided so that the amount of each air can be controlled. Further, the fluidized bed section 2 is provided with a temperature sensor 21 that measures the hearth temperature, and the temperature is detected by the temperature detector 17, and the air amount controller 18 detects the temperature.
Valve 19.2 which controls the air volume of 12°13 by commanding
0 can be opened and closed to keep the hearth temperature constant.

Next, the operating state of this device will be explained.

The dust 15 falls from the dust supply device 16 into the fluidized bed section 2 and is burned. By creating a difference in the superficial velocity between the fluidized bed part A4 and the fluidized bed part port 5 of the fluidized bed part 2, and by reversing the fluidized medium by the deflector 3, the fluidized medium is rotated, and the non-combustible materials are Move to the incombustible material outlet 6 as shown in Figure 11a. The heat recovery section is installed in a direction 90 degrees from the incombustible material outlet 6. A partition wall 7 is provided on one side of the periphery of the fluidized bed section 2 in a direction of 90 degrees from a non-combustible material outlet that is sufficiently far from the center of the fluidized bed section 2 where garbage falls.The lower and upper parts of the partition wall 7 allow fluidized sand to move. It is cut out like this. A heat exchanger 9 is installed inside the partition wall 8 between the partition wall 7 and the furnace wall to recover heat from the fluidized sand. The amount of heat to be recovered depends on the amount of sand circulating inside the partition wall 8 and the heat transfer coefficient of the heat exchanger 9 and the circulating amount of heat transfer sand.

When the amount of sand circulation is large, the amount of heat exchange is large, and when the heat transfer coefficient between the heat exchanger 9 and the amount of circulation is large, the amount of heat exchange is large.

These two variables are varied to maintain a constant hearth temperature. The amount of sand circulating inside the partition wall 8 is determined by the amount of sand circulating inside the partition wall 1.
A nozzle whose flow rate can be controlled separately from the nozzle for the main flow air 11 is installed in the main flow air 11, and the amount of heat exchange section circulating air 12 supplied from there is increased or decreased by opening and closing a valve 19 using an air amount controller 18. Change by. Sand circulation is caused by the difference between the amount of air in front of the bulkhead and the flow rate inside the bulkhead 8. Therefore, when increasing the circulation amount, increase the difference between the flow rate and the air amount inside the partition wall 8, and when decreasing the circulation amount, increase the flow rate difference between the air amount inside the partition wall 8 and the air amount inside the partition wall 8. Reduce the difference.

The heat transfer coefficient of the heat exchanger 9 and the circulation amount are determined by installing a nozzle that can control the flow of air separately from the nozzle of the main flow air 11 on the hearth surface between the partition wall and the furnace wall, and supplying the air from there. The heat exchange section air 131 is changed by increasing or decreasing the amount by opening and closing the valve 20. The amount of air 13 in the heat exchange section changes the range in which the inside of the partition wall 8 changes from a fixed bed to a fluidized bed, and utilizes the fact that the heat transfer coefficient changes rapidly during this period, as is generally known. The fluidized bed inside the bulkhead will be sloped to allow easy circulation of fluidized sand.

As shown in this example, in a rectangular furnace, the shape of the incombustible material outlet is not limited by providing a partition wall in a direction 90 degrees from the incombustible material outlet.

〔Effect of the invention〕

According to the present invention, by providing a partition wall in a direction 90 degrees from the incombustible material outlet to form a heat exchange section, there is no restriction on the shape of the incombustible material outlet, and the heat exchange section is provided with a partition wall. By installing air nozzles inside and outside that can be controlled separately from the main flowing air, the hearth temperature can be maintained constant, and
Heat recovery can be performed effectively.

[Brief explanation of drawings]

FIG. 1 is a plan view of a fluidized bed incinerator showing an example of the present invention;
FIG. 2 is a sectional view taken along line BB in FIG. 1, and FIG. 3 is a sectional view of a conventional fluidized bed incinerator. ■Hearth, 2...Fluidized bed section, 3...Deflector, 4...Fluidized bed section A, 5--Fluidized bed 80.6...
・Nonflammable material outlet, 7...Bulkhead, 8...Inside the partition, 9
... Heat exchanger, 10 ... Wind box, 11 ... Fluid air, 12 ... Heat exchange section circulating air, I3 ... Heat exchange section air, 14 ... Debris falling section, 15.・・Garbage, 16・・
・Dust supply device patent applicant: Ebara Corporation Representative: Keito Yoshimine
Pine 1) Ome 2F

Claims (1)

[Scope of Claims] 1. In a fluidized bed incinerator that incinerates incinerated materials and moves the noncombustibles to the noncombustibles outlet by swirling the fluidized medium by main flowing air, the flow direction is 90 degrees from the noncombustibles outlet. A partition wall is provided on at least one side around the floor, a heat exchanger or a boiler is provided inside the partition wall, and a nozzle that can control the flow rate separately from the main flow air nozzle is installed on the hearth surface in front of the partition wall. A fluidized bed incinerator characterized by: 2. The fluidized bed incinerator according to claim 1, wherein a nozzle whose flow rate can be controlled separately from the main fluidizing air nozzle is installed on the hearth surface between the partition wall and the furnace wall. Floor incinerator. 3. Incinerate the incombustible material, move the noncombustibles to the noncombustible material outlet by swirling the fluidized medium by the main fluidizing air, and provide a partition wall on at least one side around the fluidized bed part in a direction 90 degrees from the noncombustible material outlet. , in the operation of a fluidized bed incinerator with a heat exchanger or boiler installed inside the partition wall, the hearth surface in front of the partition wall and the hearth surface between the partition wall and the furnace wall are provided with separate nozzles for the main fluidized air. A nozzle that can control the flow rate is installed in the heat exchanger, and the amount of circulating air supplied from the heat exchanger section is adjusted, thereby controlling the amount of heat exchange and keeping the hearth temperature constant. How to operate a fluidized bed incinerator.