JPS5928221Y2 - Fluidized bed combustion equipment - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a fluidized bed combustion apparatus, and more particularly to an improvement of a fluidized bed combustion apparatus including a group of heat transfer tubes in a fluidized bed forming area.

Conventionally, a fluidized bed boiler equipped with a group of heat transfer tubes in a fluidized bed forming area has one end connected to a heat transfer tube header T in the fluidized bed forming area formed by a fluidized medium 3, as shown in FIGS. 1 and 2. The heat exchanger tubes 8 whose other ends are connected to the heat exchanger tube header 9 are arranged with uniform pinching over the entire fluidized bed formation area.

In a fluidized bed boiler having such a group of heat transfer tubes,
Air is introduced from the air pipe 5 through the air distribution plate 2 to make the fluidized medium 3 into a fluidized state, and fuel is supplied from the fuel supply port 4, and the heat generated by combustion of the fuel in the fluidized bed is passed through the heat transfer tube group 8. It is designed to be collected using a liquid medium.

The gas generated in the fluidized bed boiler 1 is discharged from the furnace through the exhaust gas outlet 6.

In such a fluidized bed boiler, various troubles occur depending on the type of fuel supplied from the fuel supply port 4.

That is, when the fuel is solid, there is a problem that the solid fuel collides with the heat exchanger tubes 8 and damages the heat exchanger tubes 8.

In addition, when the fuel is liquid or highly humid, the heat exchanger tube 80
There is a problem in that fuel adheres and accumulates on the surface and local combustion of fuel occurs on the surface of the heat transfer tube 8, resulting in clinker formation.

Furthermore, if the fuel has high humidity or a long ignition time,
Due to the heat absorption effect of the heat transfer tubes 8, the temperature of the fluidized medium drops significantly, and the temperature of the fluidized bed falls below the natural temperature of the fuel, leading to a misfire.

In addition, regardless of the type of fuel, heat transfer tubes 8 are also installed near the fuel supply port 4 (), which inhibits the diffusion effect of the fuel, and particularly in the case of a fluidized bed with a large bed area, the temperature distribution within the bed is It becomes unbalanced.

The purpose of the present invention is to provide a fluidized bed combustion device that can improve combustion efficiency by reducing unburned matter by preventing an abnormal drop in fluidized bed temperature that would have a particularly negative effect on initial combustion. be.

In order to achieve the above object, the fluidized bed combustion apparatus according to the present invention includes a group of heat transfer tubes installed in the fluidized bed formation area in the apparatus, and an opening in the air distribution plate with the fuel supply port facing the fluidized bed formation area. installed to allow fuel to be introduced in the direction of air flow,
The heat transfer tube group is arranged in a fluidized bed formation area excluding the vicinity of the fuel supply port.

The implementation fee of the present invention will be explained below with reference to the accompanying drawings.

In FIGS. 3 to 4, parts that are the same as or corresponding to those in FIGS. 1 and 2 are designated by the same reference numerals.

3 and 4, the difference from the conventional fluidized bed boiler shown in FIGS. 1 and 2 is that the fuel supply port 4 is installed in the center of the air distribution plate 2; Eight groups of heat exchanger tubes arranged in an even pinch are installed in the fluidized bed formation area except for the vicinity.

That is, as shown in FIG. 4, the heat exchanger tubes 8, which have one end connected to the heat exchanger header 1 and the other end connected to the heat exchanger header 9, are installed near the fuel supply port 4, and the other parts are equally spaced. It is arranged in a pinch.

In a fluidized bed boiler in which 8 groups of heat transfer tubes are installed in such an arrangement, when fuel is dropped from the fuel supply port 4, the temperature drop of the fluidized medium is suppressed because the heat transfer tubes 8 are not installed at the fuel supply position. be done.

That is, when water in the fuel evaporates, the high-temperature fluidizing medium flowing around the dropped fuel immediately compensates for the latent heat of vaporization that would be taken away, so that the temperature drop of the still moving medium is suppressed.

If there is a heat transfer tube at the fuel injection position, the temperature of the fluidized medium may drop too much due to the heat absorption effect of the heat transfer tube without compensating for the latent heat of vaporization.

Incidentally, as a result of measuring the temperature drop in the fluidized bed in this example and the conventional example by feeding high-humidity fuel or flame-retardant fuel, the temperature drop in the fluidized bed was conventionally about 100°C. However, in this example, the temperature drop in the fluidized bed was able to be within about 30°C.

This shows that in this example, the fluidized bed boiler can be operated at a stable bed temperature.

Next, when liquid fuel or high-humidity fuel is supplied from the fuel supply port 4, this fuel undergoes a combustion reaction in the area where the heat exchanger tubes 8 are not installed, and then diffuses into the area of the heat exchanger tube group where the heat exchanger tubes 8 are arranged. Therefore, local combustion of fuel and generation of clinker on the surface of the heat transfer tube 8 can be prevented.

Therefore, highly reliable operation can be continued, and the chance of damage to the heat exchanger tubes 8 can be significantly reduced.

Furthermore, the lateral diffusion of the dropped fuel within the fluidized bed is promoted, and as a result, imbalance in the temperature distribution of the fluidized bed can be prevented.

When the fuel supply port 4 is installed and the height of the fluidized bed is lowered to perform low load operation as in this embodiment, the heat transfer tube group facing the fuel supply port 4 will not be exposed, so the heat transfer tube 8 Although there is little damage to the group, since the 8 groups of heat transfer tubes are not installed near the fuel supply port 4, there is an advantage that damage to the 8 groups of heat transfer tubes can be more completely prevented.

As described above, according to the present invention, an abnormal decrease in fluidized bed temperature due to fuel supply, local combustion on the surface of heat exchanger tubes, and clinker generation are prevented, and fuel diffusion within the fluidized bed is promoted to stabilize the fluidized bed. It is possible to continue operation and prevent damage to the heat exchanger tubes.

[Brief explanation of drawings]

Fig. 1 is a schematic block diagram showing a conventional fluidized bed boiler, Fig. 2 is a sectional view taken along line A-A in Fig. 1, and Fig. 3 is a schematic block diagram showing an embodiment of the present invention. Figure 4 is A- in Figure 3.
It is a sectional view taken along the A line. 1...Fluidized bed boiler, 2...Air distribution plate, 3...
・Fluid medium, 4...Fuel supply port, 5...Air pipe, 6
...Group gas outlet, 7, 9...Heat transfer tube header, 8...
heat exchanger tube.

Claims (1)

[Scope of utility model registration request] A group of heat transfer tubes is installed in a distribution layer forming area in the device, and a fuel supply port is opened in an air distribution plate facing the circulation layer forming area so that fuel can be introduced in the air flow direction, and the heat transfer tube group is A fluidized bed combustion apparatus characterized in that the fluidized bed combustion apparatus is arranged in a fluidized bed formation area excluding the vicinity of a fuel supply port.