JPH0120490Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of application of the invention] This invention is a fluidized bed that burns, reduces volume, and incinerates solid particles such as pulverized coal, desulfurization agent, sludge, industrial waste, and EP ash in a fluidized bed. This relates to a bed combustion device.

[Background of the idea]

In recent years, there has been an increase in the demand for coal due to fuel conversion from petroleum fuel to coal fuel, and since coal fuel has a higher S and N content than petroleum fuel, the amount of _SOx and _NOx generated has increased. Fluidized bed combustion, which enables cleaner combustion of coal fuel, is attracting attention from the perspective of pollution control.

For example, in a fluidized bed boiler, the fluidized medium has a particle size of 1
By using ~10 mm of coal and limestone in granular form, it can be burned at a relatively low temperature of 800 to 900 degrees Celsius in a fluidized bed, making it possible to perform desulfurization at the same time as combustion compared to conventional pulverized coal-fired boilers. It also has characteristics such as low-temperature combustion, which reduces the amount of _NOx generated.

The outline of a fluidized bed combustion apparatus will be described below with reference to FIG. 1, taking a fluidized bed boiler as an example.

An air distribution plate 2 is arranged at the bottom of the fluidized bed boiler 1. A fluidized bed 3 is formed on the air distribution plate 2 by solid particles such as coal, limestone, and combustion ash. Heat exchanger tubes 5 are arranged within the tower section 4 .

Fluidization air and combustion air to the fluidized bed 3 are supplied from an air supply pipe 6 to small air chambers 9a and 9b partitioned by a partition plate 8 of a wind box 7 below the air distribution plate 2. It is supplied to the fluidized bed 3 and the empty column section 4 via the air distribution plate 2.

On the other hand, fuel and desulfurization agent are supplied from the fuel hopper 10 to the fuel pipe 11 and from the desulfurization hopper 12 to the desulfurization agent pipe 13.
The fuel is supplied to the mixing hopper 14 through the fuel supply pipe 1.
5 to the nozzle 16 in the fluidized bed 3.

Then, it is combusted in the fluidized bed 3, and the combustion heat is absorbed by the fluidized bed 3 and the heat transfer tubes 5 of the empty tower section 4 to generate water vapor.

On the other hand, the desulfurizing agent and collected ash scattered from the empty tower section 4 to the exhaust gas outlet pipe 17 are collected by the ash collector 18 and temporarily stored in the mixing hopper 14 through the collected ash outlet pipe 19, together with the fuel and the desulfurizing agent. It is supplied to the fluidized bed 3.

Note that the exhaust gas separated by the ash collection device 18 is
The exhaust gas is discharged into the atmosphere from the exhaust gas outlet pipe 20.

The above describes the general flow conditions of fuel, desulfurization agent, air, and exhaust gas in the fluidized bed boiler 1. However, when starting the fluidized bed boiler 1 or changing the load, the level of the fluidized bed 3 is changed to the air level. It is controlled by the air flow rate from the supply pipe 6.

FIG. 2 is an enlarged detailed view of a conventional fluidized bed boiler.

In FIG. 2, numerals 1 to 17 indicate the same parts as in FIG. 1. 21 is a fluidized bed in which the fluidized medium is fluidized and is in operation (hereinafter referred to as an operating fluidized bed), 22 is a fluidized bed in which the fluidized medium is stopped (hereinafter referred to as a stopped fluidized bed), and 23 is a stopped fluidized bed 22
Stacked layers 24 and 25 on which the fluidized medium of the operating fluidized bed 21 is deposited are dampers that control the amount of air flowing into the small air chambers 9a and 9b.

In such a structure, when the fluidized bed boiler 1 is started, or when the load decreases or increases due to a load change, it is not possible to start or stop the entire fluidized bed 3 shown in FIG. As shown in Figure 2, the inside of the wind box 7 is divided into small air chambers 9a and 9b by a partition plate 8, and one damper 24 is closed to stop the combustion air from flowing into the small air chamber 9a and displace the air above the air distribution plate 2. Then, a stopped fluidized bed 22 is formed as shown on the left side of FIG. 2, and the other damper 25 is opened to supply combustion air to the small air chamber 9b so that it is distributed on the air distribution plate as shown on the right side of FIG. So-called slumping, which forms the operating fluidized bed 21, is performed.

However, when slumping is performed in the conventional fluidized bed boiler 1, since the operating fluidized bed 21 and the stopped fluidized bed 22 are adjacent to each other as shown in FIG.
Eventually, a deposited layer 23 is formed on top of the stopped fluidized bed 22, and on the other hand, the amount of fluidized medium in the operating fluidized bed 21 is drastically reduced, causing a blow-through phenomenon in the operating fluidized bed 21, and finally the operating fluidized bed 22 There was a drawback that the operation of layer 21 was impossible.

[Purpose of the invention] The present invention aims to eliminate such conventional drawbacks, and its purpose is to enable stable operation to continue even when a part of the fluidized bed is in a slumping state, and to maintain stable operation at startup. The object of the present invention is to obtain a fluidized bed combustion apparatus that can perform slumping even when the load changes.

[Summary of the idea]

In order to achieve the above-mentioned object, the present invention applies pressure above the upper surface of the stopped fluidized bed to blow back the fluidized medium from the operating fluidized bed to the stopped fluidized bed side. It is equipped with a medium injection pipe.

[Example of idea]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 3 is an enlarged detailed view of a fluidized bed combustion apparatus according to an embodiment of the present invention, FIG. 4 is a cross-sectional view taken along the line -- in FIG. 3, and FIG. 5 is an enlarged view of a pressure medium injection pipe.

In Figures 3 and 5, numbers 1 to 25
The parts up to 1 are the same as those shown in Fig. 2.

26 is a pressure medium injection pipe that prevents the fluidized medium from scattering; 27 is an injection hole that prevents the fluidized medium on the operating fluidized bed 21 side from scattering toward the stopped fluidized bed 22 side; 2
8 is a jet flow from the jet hole 27.

In such a structure, when the right half of FIG. 3 is operated as the operating fluidized bed 21 and the left half is the stopped fluidized bed 22, similar to the conventional one shown in FIG. Even when fluidized by the combustion air from the chamber 9b, the fluidized medium in the operating fluidized bed 21 collides with the jet stream 28 from the injection hole 27 of the pressure medium injection pipe 26 and falls into the operating fluidized bed 21 again. Therefore, even if slumping is performed, the fluidized medium in the operating fluidized bed 21 remains in the stopped fluidized bed 2 as in the conventional case.
The fluidized bed 21 can be operated stably while continuing slumping without scattering to the second side.

Note that the pressure medium from the injection hole 27 of the pressure medium injection pipe 26 is preferably steam, exhaust gas, air, etc. In particular, steam and exhaust gas are not effective against _NOx because the combustion temperature in the empty tower section 4 decreases. be.

[Effect of idea]

In this invention, a pressure medium injection pipe is installed on the bed side of the stopped fluidized bed to prevent the fluid from scattering, so stable operation can be achieved even when a part of the fluidized bed is in a slumping state, and when the load changes at startup. Slumping is possible even at times, allowing operation at partial load.

[Brief explanation of drawings]

FIG. 1 is a schematic system diagram of a fluidized bed combustion apparatus, FIG. 2 is an enlarged detailed view of a conventional fluidized bed combustion apparatus, FIG. 3 is an enlarged detailed view of a fluidized bed combustion apparatus according to an embodiment of the present invention, and FIG. The figure is a cross-sectional view taken along the line -- in FIG. 3, and FIG. 5 is an enlarged view of the pressure medium injection pipe. 2... Air distribution plate, 3... Fluidized bed, 7... Wind box, 8... Partition plate, 9a, 9b... Small air chamber, 21... Operating fluidized bed, 22... Stopped fluidized bed, 26... ...Pressure medium injection pipe.

Claims (1)

[Scope of claim for utility model registration] An air distribution plate is placed at the bottom of the fluidized bed to divide it into a fluidized bed and a wind box, and a partition plate is placed inside the wind box to divide it into small air chambers, and the fluidized bed is operated. In a device that operates separately into a fluidized bed and a stopped fluidized bed, a pressure medium injection pipe for blowing back the fluidized medium from the operating fluidized bed to the stopped fluidized bed side to the operating fluidized bed side is installed when the stopped fluidized bed is operated. A fluidized bed combustion device characterized in that it is provided above the top surface of a fluidized bed.