KR101354938B1 - Fluidized bed combustor - Google Patents

Abstract

The present invention relates to a fluidized bed combustion boiler that improves heat recovery efficiency while using RDF fuel exclusively. The fluidized bed combustion boiler according to an embodiment of the present invention is a fluidized bed combustion boiler using RDF fuel exclusively. A fluidized bed combustor configured to combust and combust the fluidized medium and air; A first exhaust pipe for exhausting a fluid medium and combustion gas combusted in the fluidized bed combustion furnace; A cyclone connected to the first exhaust pipe to separate the fluid from the combustion gas; A loop chamber connected to the cyclone to circulate the separated fluid medium into the fluidized bed combustion furnace; A second exhaust pipe connected to the cyclone to exhaust the separated combustion gas; And a heat recovery tower connected to the second exhaust pipe to recover heat of the combustion gas, wherein a first water pipe is installed on an inner wall of the fluidized bed combustion furnace to recover heat inside the fluidized bed combustion furnace.
The roof chamber is connected to the cyclone and the inlet for the flow medium flows; And a first compartment and a second compartment partitioned from the inlet, the first compartment being connected to the fluidized bed combustor for circulating the fluidized medium into the fluidized bed combustor. In order to recover the heat of the fluid medium is connected to an external heat exchanger, the external heat exchanger is connected to the fluidized bed combustion furnace.

Description

Fluidized Bed Combustion Boiler {FLUIDIZED BED COMBUSTOR}

The present invention relates to a fluidized bed combustion boiler, and more particularly, to a fluidized bed combustion boiler in which the heat recovery efficiency is improved while using RDF fuel exclusively.

The fluidized bed combustion boiler is a device that supplies a mixed medium such as sand and ash limestone together with fuel and air to combust and burns the heat, and uses heat of combustion generated by the combustion. The flow medium is only 1-4% of the volume of the fuel, but the heat transfer coefficient at the heat transfer surface is 250 because the flow of solids composed of the fuel and the fluid in the fluidized bed is very intense and almost complete mixed flow. -It is very high, about 500W / ㎡K, which is more energy efficient than general combustion boilers. In addition, since the combustion temperature of the fluidized bed should be lower than the melting temperature of the fluidized medium, since the operating temperature is generally made at a relatively low temperature in the range of 750-900 ° C, it is advantageous to generate / inhibit pollutants such as NOx.

RDF (Refused Derived Fuel) is made by using the solidified waste of household waste as a fuel and can be used as a fuel.In case of replacing it with the fuel of thermal power plant, the power generation efficiency can be increased by about 30%, which is about three times that of the direct incineration of waste. . Therefore, the production of electric energy is very economical, and when the thermal power generation with RDF, the power generation cost is 50 ~ 60 won / kWh is much cheaper than solar power or wind power generation.

In addition, RDF is eco-friendly because no harmful gases such as dioxins or incineration materials are generated during the manufacturing process, and RDF fluidized bed combustion technology has better combustion efficiency than other incineration methods and is more efficient than other incineration methods. Has been spotlighted as an environmentally friendly technology that can achieve the effect of desulfurization and desalting in the reduction or combustion process. For this reason, the use of fluidized bed combustion boilers with RDF as a fuel has been increasing recently.

A typical fluidized bed combustion boiler, however, recovers heat by generating hot steam from the feedwater supplied through the water pipe by the heat of combustion of the combustion gases generated in the fluidized bed combustion furnace. However, since fossil fuels, which are conventionally used in fluidized bed combustion furnaces, generate chlorine and alkali salts in the combustion gas, the water pipes can be easily corroded by chlorine and alkali salts when the water pipes are provided in the fluidized bed combustion furnace. There was a disadvantage in that the heat recovery efficiency was low because the water pipe was not directly installed in the fluidized bed combustion furnace.

The present invention provides a fluidized bed combustion boiler capable of improving combustion efficiency and heat recovery efficiency of a fluidized bed combustion furnace using RDF fuel exclusively.

A fluidized bed combustion boiler according to an embodiment of the present invention is a fluidized bed combustion boiler using RDF fuel exclusively, and includes a fluidized bed combustion furnace for mixing and burning RDF fuel with a fluid medium and air; A first exhaust pipe for exhausting a fluid medium and combustion gas combusted in the fluidized bed combustion furnace; A cyclone connected to the first exhaust pipe to separate the fluid from the combustion gas; A loop chamber connected to the cyclone to circulate the separated fluid medium into the fluidized bed combustion furnace; A second exhaust pipe connected to the cyclone to exhaust the separated combustion gas; And a heat recovery tower connected to the second exhaust pipe to recover heat of the combustion gas, wherein a first water pipe is installed on an inner wall of the fluidized bed combustion furnace to recover heat inside the fluidized bed combustion furnace.
The roof chamber is connected to the cyclone and the inlet for the flow medium flows; And a first compartment and a second compartment partitioned from the inlet, the first compartment being connected to the fluidized bed combustor for circulating the fluidized medium into the fluidized bed combustor. In order to recover the heat of the fluid medium is connected to an external heat exchanger, the external heat exchanger is characterized in that it is connected to the fluidized bed combustion furnace.

Part of the first water pipe is characterized in that it is provided exposed in the inner direction of the fluidized bed combustion furnace.

The wall surface on which the first exhaust pipe is formed among the wall surfaces of the fluidized bed combustion furnace is characterized in that the height is higher than other wall surfaces.

The first exhaust pipe is gradually narrowed in the direction of the cyclone in the fluidized bed combustion furnace, characterized in that the inlet of the cyclone is installed in a spiral (spiral) form.

The inner wall of the cyclone is characterized in that the second water pipe for recovering the heat inside the cyclone is embedded.

The heat recovery tower includes a radiation area portion having a third water pipe on a wall surface, and a convection heat transfer portion provided with a fourth water pipe on a wall surface of the radiation area portion, and water or steam in the first to fourth water pipes. Further comprising a steam drum for circulating, wherein the first to fourth water pipes are each connected in parallel with the steam drum.

delete

According to the embodiments of the present invention, the fluidized bed combustion is the area where the heat recovery efficiency is the best while minimizing the effect of corrosion caused by the combustion gas by directly embedding a water pipe capable of heat recovery on the inner wall of the fluidized bed combustion furnace that burns the RDF fuel. The heat recovery of the combustion gas in the furnace can be improved to improve the heat recovery efficiency of the fluidized bed combustion boiler.

1 is a schematic diagram showing a fluidized bed combustion boiler according to an embodiment of the present invention,
Figure 2 is a schematic diagram showing the main part of a fluidized bed combustion boiler according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It will be apparent to those skilled in the art that the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, It is provided to let you know. Wherein like reference numerals refer to like elements throughout.

1 is a schematic diagram illustrating a fluidized bed combustion boiler according to an embodiment of the present invention, and FIG. 2 is a schematic diagram illustrating main parts of a fluidized bed combustion boiler according to an embodiment of the present invention.

As shown in the drawing, a fluidized bed combustion boiler according to an embodiment of the present invention includes a fluidized bed combustion furnace 10 for mixing and combusting RDF fuel with a fluidized medium and air; A cyclone 30 connected to the downstream side of the fluidized bed combustion furnace 10 to separate the fluidized medium from the combustion gas; A loop chamber 40 connected to the cyclone 30 to circulate the separated fluid medium into the fluidized bed combustion furnace 10; It is connected to the downstream side of the cyclone 30 includes a heat recovery tower 60 for recovering the heat of the combustion gas.

In addition, the fluidized bed combustion furnace 10 and the cyclone 30 are connected to the first exhaust pipe 20 to circulate the fluidized medium and the combustion gas burned in the fluidized bed combustion furnace 10 to the cyclone 30. .

In addition, the cyclone 30 and the heat recovery tower 60 are connected to the second exhaust pipe 50 to supply the combustion gas separated from the cyclone 30 to the heat recovery tower 60.

In the fluidized bed combustor (10), the RDF fuel supplied from the outside flows together with a fluid medium such as sand to completely mix and then burn the fuel. As described above, it is possible to obtain a much better energy efficiency than the general boiler by mixing and burning fuel together with the fluidized medium.

The fluidized bed combustion furnace 10 is connected with a fuel supply means 11 for injecting RDF fuel to the top of the fluidized bed located at the bottom of the interior thereof.

On the other hand, in the present invention, the first water pipe 100 is embedded in the inner wall of the fluidized bed combustion furnace 10 so that the heat recovery in the fluidized bed combustion furnace 10 directly. Thus, water is supplied to the first water pipe 100 so that heat recovery is performed by water in the first water pipe 100.

The first water pipe 100 is preferably embedded in the inner wall of the fluidized bed combustion furnace 10 in order to prevent corrosion by combustion gas, but in the present invention using RDF fuel, corrosion occurs during combustion of RDF fuel. Since less material is generated than the fossil fuel, a portion of the first water pipe 100 may be exposed inward from the inner wall of the fluidized bed combustion furnace 10 to maximize heat recovery efficiency.

The fluidized bed combustion furnace 10 is configured to reduce the cross-sectional area of the lower part in the case of a large size to maintain the lower flow velocity of the combustion furnace, and to maintain the vertical column shape so that the upper and lower cross-sectional area is the same in the case of a small size. For example, the fluidized bed combustion furnace has a high fireproof wall in the form of a square column. In this case, the cross section of the fluidized bed combustion furnace 10 is not limited to a quadrangle, and may be embodied by being changed into various shapes of a circle or a polygon.

Among the wall surfaces of the fluidized bed combustion furnace 10, the wall surface on which the first exhaust pipe 20 is formed is formed to have a height higher than that of other wall surfaces to reduce wear caused by the flow of the fluidized medium.

The first exhaust pipe 20 is connected to an upper region of the fluidized bed combustion furnace 10 and is a means for circulating the fluidized medium and the ointment gas combusted in the fluidized bed combustion furnace 10 to the cyclone 30. The first exhaust pipe 20 is installed to be gradually narrowed in the fluidized bed combustion furnace 10 in the direction of the cyclone 30 so that the flow rate of the inlet side of the cyclone 30 is faster than the outlet flow rate of the fluidized bed combustion furnace 10. .

The cyclone 30 is a means for separating the flow medium and the combustion gas by the centrifugation principle, the flow medium having a relatively large particle size is separated by centrifugation to the loop chamber 40 Combustion gas circulated and having a relatively small particle size is provided to the heat recovery tower 60 through the second exhaust pipe 50.

It is preferable that the inlet of the cyclone 30 is installed in a spiral form to double the centrifugal force of the fluid and the combustion gas flowing into the cyclone 30.

In addition, in the present invention, the second water pipe 200 is incorporated in the inner wall of the cyclone 30 to recover the heat of the combustion gas in the cyclone 30.

The lower end of the cyclone 30 is connected to the roof chamber 40.

The loop seal is a means for circulating the fluid medium separated from the cyclone 30 back to the fluidized bed combustion furnace 10. In the present invention, heat is introduced through the fluid medium introduced into the loop chamber 40. The external heat exchanger 44 is connected to the roof chamber 40 to recover the heat.

In other words, the roof chamber 40 is divided into three spaces. Preferably, the inlet part 41 is connected to the lower end of the cyclone 30 and the fluid medium is introduced therefrom, and in the inlet part 41. It is divided into a first compartment 42 and a second compartment 43 which are branched and partitioned in both directions.

Thus, some of the flow medium introduced into the inlet portion 41 flows to the first compartment 42 and then circulated directly to the fluidized bed combustion furnace 10, and among the flow medium introduced to the inlet portion 41. Some flow to the second compartment 43 and then circulate to the fluidized bed combustion furnace 10 after heat is recovered from the external heat exchanger 44. At this time, it is preferable that the amount of flow medium branched into the first compartment and the second compartment is determined and adjusted by the operator's choice.

At this time, the bubble chamber is formed in the roof chamber 40 and the external heat exchanger 44 to receive fluidized air from the forced blowing fan. Thus, it is provided with the power to smoothly circulate the fluid.

Meanwhile, the combustion gas separated from the cyclone 30 is provided to the heat recovery tower through the second exhaust pipe 50.

The heat recovery tower 60 is a means for recovering the heat of the combustion gas provided separately from the cyclone 30. The heat recovery section 60 includes a radiation zone portion 61 having a third water pipe 300 on a wall thereof, and the radiation zone portion. Subsequent to 61, the convective heat transfer part 62 is provided with a fourth water pipe 400 on the wall.

In other words, in the heat recovery tower 60, an empty pass 61, which is a passage through which the combustion gas separated from the cyclone 30 flows from the top to the bottom, and the radiation area 61. It is continuously connected to the lower end of the convection heat conduction (convection pass) (62) which is a passage for flowing the combustion gas from the bottom to the top.

A third water pipe 300 is provided on an inner wall of the radiation area portion 61, and a fourth water pipe 400 is provided on the convective heat transfer part 62. In the convection heat exchanger 62, a superheater 63, a coal cutter 64, and an air preheater 65 are disposed.

The superheater 63 is arranged in the vertical direction to the convection heat exchanger 62 to obtain an effect of narrowing the installation area of the heat recovery tower (60).

And, the coal mill 64 is installed in the downstream flow of the superheater 63 and serves to heat the water supply to the steam drum 500 to be described later. The coal mill 64 is arranged in the axial direction to increase the heat transfer effect, while being configured as a coil bundle. For example, in this embodiment, it consists of two bundles.

In the air preheater 65, three modules are installed in a stacked shape, and air is preferably flowed perpendicularly to the tube bundle inside the tube and combustion gas outside the tube.

The superheater 63, the coal cutter 64, and the air preheater 65 are well known to those skilled in the art, and may be installed in various ways and configurations.

Meanwhile, a steam drum 500 for circulating water or steam flowing through the first water pipe 100 to the fourth water pipe 100, 200, 300, and 400 is provided. Therefore, the first to fourth water pipes (100, 200, 300, 400) are preferably connected in parallel with the steam drum 500, respectively.

The water supplied to the economizer 64 is preheated while passing through the economizer 64 and then directed to the steam drum 500 and then supplied to the first to fourth water pipes 100, 200, 300, 400. The mixture is further heated while passing through the fluidized bed combustion furnace 10, the cyclone 30, the radiation area portion 61, and the convective heat transfer portion 62 to be a mixture of air and water, and circulated back to the steam drum 500.

The water vapor separated in the steam drum 500 is fed to the superheater 63 and further heated while passing through the superheater 63 and the superheated water vapor is sent to the steam turbine.

Then, a thermothermal tower 70 and a bug filter 80 are disposed on the downstream side of the heat recovery tower 60.

The temperature reduction tower 70 is a means for further lowering the temperature of the combustion gas that has passed through the heat recovery tower 60, and the bug filter 80 collects hydrogen chloride, sulfur oxide, dust, and the like in the combustion gas. In the current side, neutralizing agents such as slaked lime and a reaction aid are added to the combustion gas. The combustion gas passing through the bug filter 80 is discharged into the atmosphere through the chimney 90.

The use state of the fluidized bed combustion boiler comprised as mentioned above is demonstrated.

First, the preheated air is supplied through a wind box and a jet plate provided in the lower portion of the fluidized bed combustion furnace 10 while the fluidized medium is filled in the fluidized bed combustion furnace 10. The RDF fuel is supplied to the fluidized bed combustion furnace 10 using the fuel supply means 11 while the fluidized medium is flowed in the fluidized bed combustion furnace by air. Accordingly, the RDF fuel is combusted in the fluidized bed combustion furnace 10 to heat the air and the fluidized medium. At this time, the first water pipe 100 provided in the fluidized bed combustion furnace 10 recovers heat of the fluidized medium and the combustion gas.

The heated fluid and the combustion gas are supplied to the cyclone 30 as the flow rate increases through the first exhaust pipe 20, and the cyclone 30 has a relatively large particle flow medium due to the centrifugation principle. Relatively small combustion gases are separated. In the cyclone 30, heat is recovered by the second water pipe 200 while the fluidized medium and the combustion gas are separated.

Meanwhile, the fluid medium separated from the cyclone 30 flows to the inlet part 41 of the roof chamber 40, and then a part of the fluid medium is circulated to the fluidized bed combustion furnace 10 through the first compartment 42. Is flowed to the external heat exchanger 44 through the second partition 43, heat is recovered, and then circulated to the fluidized bed combustion furnace 10.

In addition, the combustion gas separated from the cyclone 30 flows to the heat recovery tower 60 through the second exhaust pipe 50. The combustion gas flowing into the heat recovery tower 60 passes through the radiation area portion 61 and the convective heat transfer portion 62 in sequence to recover heat by the third water pipe 300 and the fourth water pipe 400.

The combustion gas cooled while passing through the radiation area portion 61 and the convective heat transfer portion 62 is further cooled while passing through the temperature reduction tower 70, and then the harmful component is collected in the bug filter 80. Through the atmosphere.

Although the present invention has been described with reference to the accompanying drawings and the preferred embodiments described above, the present invention is not limited thereto but is limited by the following claims. Accordingly, those skilled in the art will appreciate that various modifications and changes may be made thereto without departing from the spirit of the following claims.

10: fluidized bed combustion furnace 11: fuel supply means
20: first exhaust pipe 30: cyclone
40: roof chamber 41: inlet
42: first compartment 43: second compartment
44: external heat exchanger 50: second exhaust pipe
60: heat recovery tower 61: radiation area portion
62: convection heater 63: superheater
64: Binder 65: Air Preheater
70: Thermal Tower 80: Bug Filter
90: chimney 100: first water pipe
200: second water pipe 300: third water pipe
400: fourth water pipe 500: steam drum

Claims (7)

Fluidized bed combustion boiler using RDF fuel exclusively,
A fluidized bed combustion furnace for mixing and combusting the RDF fuel with a fluid medium and air;
A first exhaust pipe for exhausting a fluid medium and combustion gas combusted in the fluidized bed combustion furnace;
A cyclone connected to the first exhaust pipe to separate the fluid from the combustion gas;
A loop chamber connected to the cyclone to circulate the separated fluid medium into the fluidized bed combustion furnace;
A second exhaust pipe connected to the cyclone to exhaust the separated combustion gas;
A heat recovery tower connected to the second exhaust pipe to recover heat of the combustion gas;
The inner wall of the fluidized bed combustion furnace has a first water pipe for recovering heat inside the fluidized bed combustion furnace,
The roof chamber is connected to the cyclone and the inlet for the flow medium flows; It consists of a first compartment and a second compartment partitioned from the inlet,
The first compartment is connected to the fluidized bed combustor for circulating the fluidized medium into the fluidized bed combustor,
And the second compartment is connected to an external heat exchanger to recover heat of the fluidized medium, and the external heat exchanger is connected to the fluidized bed combustion furnace.
The method according to claim 1,
Part of the first water pipe is a fluidized bed combustion boiler, characterized in that provided in the inward direction of the fluidized bed combustion furnace.
The method according to claim 1,
The fluidized bed combustion boiler, characterized in that the wall surface of the wall of the fluidized bed combustion furnace is formed is higher than the other wall surface.
The method according to claim 1,
The first exhaust pipe becomes narrower in the cyclone direction in the fluidized bed combustion furnace,
Fluidized bed combustion boiler, characterized in that the inlet of the cyclone is installed in a spiral (spiral) form.
The method according to claim 1,
The inner wall of the cyclone fluidized bed combustion boiler, characterized in that the second water pipe for recovering the heat inside the cyclone is built.
The method according to claim 5,
The heat recovery tower includes a radiation area portion having a third water pipe on the wall surface, and a convection heat transfer portion provided with a fourth water pipe on the wall surface after the radiation area portion.
Further comprising a steam drum for circulating water or steam in the first to fourth water pipes,
The first to fourth water pipes are each connected in parallel with the steam drum.
delete

Images