JPS60235902A - Fluidized-layer combustion system - Google Patents

Abstract

PURPOSE:To miniaturize a fluidized-layer plant by an integrated construction of a main and an auxiliary combustion furnaces. CONSTITUTION:To form all apparatuses in compact, the auxiliary combustion furnace 11 is formed in a cutout section of the main combustion furnace. In this connection, the cutout section 8 is formed for the purpose of maintaining a flowing speed of the gas under a reduction of a cross-sectional area of the hollow tower section. Owing to the formation of the auxiliary combustion furnace 11 in this manner, a medium, falling from multihole plate 12 availing a slope of the cutout section 8 may be exhausted to the outside through the duct 13. Thereby, the fluidized-bed combustion system including the auxiliary combustion furnace may be miniaturized, and an installation contained in a small area being made possible.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fluidized bed combustion apparatus, and more particularly to a combustion apparatus that can simplify the combustion plant.

Combustion devices using fluidized beds have various advantages and have recently attracted attention in various fields, and their practical use is progressing. The advantages of this fluidized bed combustion apparatus are explained below using a fluidized bed boiler that uses coal as fuel.

(1) The heat transfer coefficient within the fluidized bed is extremely high, the heat transfer area within the bed can be reduced, and the entire boiler can be downsized.

(2) By mixing and stirring with a fluidized medium, coal and air are mixed well, and even low-grade coal can be burnt well.

(3) Intralayer desulfurization is possible by using a desulfurizing agent such as limestone or dolomite as a fluidizing medium or adding it to a fluidizing medium.

(4) Since it is burned at a relatively low temperature, ash does not melt, slagging can be prevented, and little NOx is generated.

Figure 1 shows the system of a coal-fired fluidized bed boiler.

Reference numeral 1 in the figure is the main combustion furnace, in which fluidized air A is provided.

Coal 3 is supplied to the fluidized bed 2 and burned. The heat generated by combustion is recovered by an interlayer heat exchanger tube (not shown) and an ice wall tube forming the furnace wall. On the other hand, the combustion gas ascends through the empty tower section 4 and is discharged to the outside. A considerable amount scatters into the sky tower. In addition, there is also a considerable amount of unburned matter that could not be combusted within the time that it remained in the layer.

Combustion gas containing such ash and unburned matter is discharged from the main combustion furnace 1 and then collected in a dust collector 5 such as a multi-cyclone. The collected ash and unburned matter are fed into the sub-combustion furnace 6 and burned there. In addition, since unburned matter cannot be combusted in the main combustion furnace 1, which performs combustion in a temperature range of 700 to 900°C, for example, it is operated at a temperature higher than this temperature range (for example, 1ooo'c). . The exhaust gas discharged from the sub-combustion furnace 6 is collected by a dust collector 7.
The ash content is collected and the exhaust gas from which dust has been removed is combined with the exhaust gas discharged from the dust collector 5 and released into the atmosphere.

As mentioned above, in conventional combustion equipment, the main combustion furnace and the auxiliary combustion furnace are installed separately, so the installation area of the plant becomes vast, and various difficulties have arisen in recent years in acquiring land for the plant. There is a big problem with the above-mentioned method of installing a combustion furnace, which requires a vast amount of land.

The present invention has been constructed in view of the above problems, and it is an object of the present invention to provide a fluidized bed combustion apparatus that can achieve downsizing of a fluidized bed plant.

In short, the present invention is a fluidized bed combustion apparatus in which a main combustion furnace and a sub-combustion furnace are integrated.

Examples of the present invention will be described below.

In FIG. 2, numeral 10 is a main body of the fluidized bed combustion apparatus, and 11 is a sub-combustion furnace formed in a part of this main body. By forming this sub-combustion furnace in the notch 8 of the main combustion furnace 1 shown in FIG. 1, the entire apparatus can be made compact. Incidentally, the notch is formed to reduce the cross-sectional area of the empty column and maintain the gas flow rate. By forming the sub-combustion furnace in this manner, it is preferable to configure the medium that has fallen from the perforated plate 12 to be discharged to the outside via the conduit 13 using the notch slope.

In the apparatus configured as above, the air A□ supplied into the apparatus main body 10 flows into the medium layer through the perforated plate 14,
form. Coal 3 is supplied to this fluidized bed 2 and burned. The combustion exhaust gas containing ash and unburned matter is in the empty tower section 1.
5, and ash and unburned matter are collected in the dust collector 5. The collected ash and unburned matter are introduced into a fluidized bed 17 formed in the sub-combustion furnace 11 via a pipe 16 and burned.

A is fluidized air supplied to the sub-combustion furnace 11.

Most of the ash newly generated by the combustion of the ash and unburned materials introduced into the furnace overflows to the outside through the overflow port 18.
The remaining ash reaches the dust collector 7 and is collected together with the exhaust gas rising in the empty tower section 19. The dust-removed exhaust gas joins the exhaust gas discharged from the dust collector 5 and is released into the atmosphere.

By implementing this invention, the fluidized bed combustion apparatus including the sub-combustion furnace can be downsized and can be installed in a small installation area.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of a conventional fluidized bed combustion apparatus. FIG. 2 is a system diagram of a fluidized bed combustion apparatus according to the present invention. 2.17・River...Fluidized bed 10...Main combustion device 11...Sub-combustion furnace

Claims (1)

[Claims] 1. In a device in which unburned content discharged from the main combustion device is combusted in a sub-combustion furnace, the sub-combustion furnace is formed as a part of the main combustion device so that both are integrated. A fluidized bed combustion apparatus characterized by: 2. The fluidized bed combustion apparatus according to claim 1, characterized in that a sub-combustion furnace is formed in a notch of the main combustion apparatus.