JPS6123442B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the structure of a fluidized bed incinerator, particularly the shape of the furnace in the upper part of the column.

As shown in Fig. 1, the conventional fluidized bed incinerator 1a has a structure that includes a fluidized bed section 2a that performs primary combustion and an empty column that serves as a secondary combustion zone that completely burns unburned matter generated in the fluidized bed section 2a. The part 3a is both cylindrical and stands upright, and is connected to a cylindrical flue 4a at the exhaust gas outlet perpendicular to the axis of the cylindrical body.

Furthermore, industrial waste, which is generally incinerated, contains low melting point compounds such as vanadium and sodium. Therefore, the low melting point substances are entrained in the exhaust gas, and if the exhaust gas is led to the flue 4a at the incineration temperature (for example, 850°C), the low melting point substances will adhere and grow on the inner wall of the flue 4a, causing the flue gas to grow. This will lead to an increase in pressure loss.

Therefore, a cooling air nozzle is provided in the upper part of the tower section 3a to cool the temperature of the exhaust gas guided to the flue 4a to below the melting point of the low melting point substance (for example, 350°C), and the flue gas of the low melting point substance is Prevents adhesion to inner walls.

When such a structure is adopted, a phenomenon occurs in which a vortex 5a is generated at the corner of the upper part of the fluidized bed furnace, that is, the upper part of the cavity, and a descending gas flow 6a is partly generated along the wall surface. A part of this returning descending gas is sent to the cooling air nozzle 7a.
Since the exhaust gas is accompanied by cold air, the temperature of the exhaust gas decreases, making it impossible to maintain the amount of heat and temperature required for combustion and decomposition of unburned substances in the exhaust gas, and as a result, extra auxiliary fuel is required for these gases. It has caused drawbacks.

The purpose of this invention is to eliminate such drawbacks and to propose a structure for a fluidized bed incinerator that does not generate a return downward gas flow and allows sufficient mixing of high-temperature exhaust gas and cooling gas (for example, air). do.

In short, in order to mix cooling gas and high-temperature exhaust gas without creating a vortex in the exhaust gas passage, the cross-sectional area of the exhaust gas passage is gradually reduced to such an extent that no vortex is generated, and the direction in which the cooling gas is ejected is It is characterized by being approximately along the wall surface and facing in the downstream direction of the exhaust gas.

An embodiment of this invention will be explained with reference to FIG.
The upper part of the empty column has a nearly circular cross-sectional shape, and the exhaust gas flow is deflected by 90 degrees. Furthermore, in order to improve the mixing of the exhaust gas flow and cooling air, the axis of the cooling air supply nozzle is set at an angle α with respect to the horizontal.
A plurality of air supply nozzles 7 are provided inclined at an angle β with respect to the tangential direction of the peripheral wall of the cross section. α is 60~
45, β is preferably 20 to 45.

FIG. 3 shows an example where there is no change in direction of the exhaust gas flow. However, for convenience in manufacturing, the curved portion 8 in the longitudinal section may be a collection of shrimp-like bent lines.

By implementing this invention, it is possible to reduce fuel consumption without generating a return downward gas flow, and various effects such as reducing the exhaust gas temperature at the upper part of the tower and reducing deposits are produced. It is something.

[Brief explanation of the drawing]

Figure 1 is a vertical cross-sectional view of a conventional fluidized bed incinerator;
The figure is a longitudinal sectional view of the first embodiment of the present invention, FIG. 3 is a longitudinal sectional view of the second embodiment, and FIG. 4 is a line A-A in FIG. 2.
FIG. 1... Fluidized bed incinerator, 2... Fluidized bed section, 3...
Sky tower section, 4...exit flue, 7...cold air supply nozzle.

Claims (1)

[Scope of Claims] 1. The exhaust gas passage in the upper part of the fluidized bed incinerator has a cross-sectional area that gradually decreases toward the discharge side, and a nozzle for spouting a cooling medium into the exhaust gas at the top of the furnace is provided in this exhaust gas passage, and further, the nozzle 1. A fluidized bed incinerator characterized in that the cooling medium is ejected in the direction of exhaust gas downstream. 2. Claims characterized in that the exhaust gas passage in the upper part of the fluidized bed incinerator changes its direction by approximately 90 degrees about the furnace axis, and its cross-sectional area gradually decreases toward the discharge side. The fluidized bed incinerator according to item 1.