JPS589325B2 - Fluidized bed pyrolysis or incinerator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fluidized medium for use in a fluidized bed pyrolysis or incinerator.

In particular, it provides a fluid medium suitable for fluidized bed incinerators for general waste such as municipal waste and industrial waste such as sludge.

Incinerators or pyrolysis furnaces using a fluidized bed use a high-temperature fluidized medium, so compared to other types of combustion or cracking furnaces, such as mechanical ones or jacket-type pyrolysis furnaces, the incinerator or pyrolysis furnace It has the advantage of fast decomposition speed.

In addition, the gas (air) required to flow the medium often mixes well with the material to be combusted and becomes the entire combustion air, which has the advantage that thermal decomposition or combustion can be completed with a smaller amount of air.

The role of the fluidized medium used in the fluidized bed is to maintain the media layer at the required temperature and to continue feeding the treated material into the fluidized bed continuously with a small amount of auxiliary fuel or without supplying fuel. The fine particles used as the fluidizing medium must not be able to melt or solidify at the required temperature and inhibit fluidity, and must be heat resistant. It must be able to conduct heat well to the workpiece.

Conventionally, a finely granular inert proboscis has been used, and the inert material is usually fine sand or ceramic particles.

On the other hand, since these conventional media have a high specific gravity, pressure loss is large during flow, and as a result, it is necessary to increase the discharge pressure of a blower that sends flow air.

The present invention uses artificial aggregate with a small specific gravity as a fluid medium, thereby lowering the discharge pressure of the blower and reducing the power required for the blower.

In addition, when general waste such as municipal garbage is to be incinerated,
Compared to sand media, which has a specific gravity of about 2.6, the specific gravity is smaller, so the difference in specific gravity with glass, metal, and other noncombustibles in general waste is greater, so the separation effect of noncombustibles in a fluidized bed is There are benefits to getting better.

The artificial aggregate referred to in the present invention is made by crushing and calcining expansive shale, and has a true specific gravity of 1.2 to 1.8 and a particle size of 0.5 mm.
It is within the range of 3.0 mm to 3.0 mm.

The fluid medium used in the present invention has a true specific gravity of 1.2 to 1.
．． 8 is required.

That is, if the true specific gravity is 1.2 or less, scattering will be severe in the fluidized bed furnace, and if it is 1.8 or more, the effect of reducing the discharge pressure of the blower will be small.

Moreover, the size of the particles is Q, 5mm to 3mm. It is required to be within the range of Qmm.

If the particle size is 0.5 mm or less, dusting occurs; 3. Qmm
Further north, the heat conductivity of the particles decreases, and the advantage of a fluidized bed is lost.

Preferred is l. It ranges from Qmm to 2.0 dragons.

Further, it is more preferable that the porosity is 0.3 to 0.45.

Compared to sand, etc., which are generally used as a fluidizing medium, the artificial aggregate that is the subject of the present invention has a fluidity similar to that of sand, and has properties such as strength that are not much different from sand, but the pressure loss during fluidization is will be much less.

In other words, when sand etc. is in a fluid state, the pressure loss is usually 150 mmH20 per 10 cm of fixed sand layer.
However, according to the present invention, in order to obtain the same level of fluidity as sand, it is necessary to use 70 mmH20 to 12
0mmH20 is sufficient and power reduction is achieved.

Hereinafter, comparative examples and examples will be shown to demonstrate the effects of the present invention.

The fluidized bed pyrolysis furnace 1 used in the experiment has an inner diameter of 20 cm, and as shown in the figure, a blower 6 is used to send fluidized air as a fluidized medium through a wind box 2 and a distribution plate 3 to the furnace, and the material to be thermally decomposed is is fed into a fluidized bed pyrolysis (incineration) furnace via a feeder 7.

A portion of the input material is combusted in the fluidized medium bed 4 and the pyrolysis zone 5, and the remaining portion is pyrolyzed by the heat of combustion.

The pressure difference between the pressure in the wind box 2 and the pressure in the pyrolysis zone 5 is indicated by a pressure gauge 11.

Since the pressure drop due to the dispersion plate 3 is constant, the larger the differential pressure, the greater the pressure loss due to fluidization.

Comparative example 1 Polypropylene was pyrolyzed using the experimental apparatus described above.

River sand was used as the fluidizing medium. River sand has a specific gravity of 2.6.
Particle size Q, lmm to 2. Qmm (average particle size 15mm),
A medium with a porosity of 0.4 was used, the medium layer thickness was 10 cm, and the superficial velocity was U.

= 5 cm/sec. 9.2 kg of crushed Bolibutypyrene per hour was processed and waxy cracked oil s. OK
I got a 9.

The pyrolysis temperature was 500°C±10°C, the differential pressure between the wind box and the pyrolysis zone at this time was 280 mm water column, and the resistance of the dispersion plate was 100 mm water column.

Example 1 The same equipment as in Comparative Example 1 was used, using artificial lightweight aggregate as the fluid medium.

The artificial lightweight aggregate has a specific gravity of 1.6 and a particle size of Q. lmm to 2mm
(average particle size 1.5 mm) porosity 0.4,
Medium layer thickness lOcm, superficial velocity U.

= 9.2 crushed polypropylene per hour at 5 cm/sec
kg was treated at a decomposition temperature of 500°C ± 10°C to obtain 8.0 kg of waxy recovered oil.

At this time, the differential pressure between the wind box and the pyrolysis zone is 2
At 00 mm water column, the resistance of the dispersion plate was too mm water column.

The differential pressure during flow was 80 mm smaller than in Comparative Example 1 by 80 mm of water column.

Comparative Example 2 The river sand used in Comparative Example 1 was used in the apparatus of Comparative Example 1, and the superficial velocity U was set.

−40 cm/sec, and factory wastewater treatment sludge (moisture content 6
0%, coarse flakes) were incinerated at a rate of 6.0k9 per hour.

At this time, the differential pressure between the wind box and the pyrolysis zone is 28
omm water column, the temperature of the sand required to continue combustion is 9
The temperature was 00°C±50°C.

The resistance of the dispersion plate is 100 mm water column.

Example 2 Under the same conditions as Comparative Example 2, the artificial aggregate used in Example 1 was used as a medium, and factory wastewater treatment sludge (moisture content 6
0%) was incinerated at a rate of 6.0 kg for 1 hour.

At this time, the differential pressure between the wind box and the pyrolysis zone is 2
00 mm of water column, and the temperature of the sand required to continue combustion was 900°C ± 20°C.

The resistance of the distribution plate was 10 Qmm water column. The differential pressure during flow was 80 mm less water column than Comparative Example 2.

[Brief explanation of drawings]

The drawing is a flow sheet of a fluidized bed type pyrolysis or incinerator used in experiments of the present invention. 11...Fluidized bed type pyrolysis (incinerator) furnace, 2...Wind box, 3...Dispersion plate, 4...Fluidized medium layer, 5...1 Thermal decomposition (combustion) zone, 61...Blower, 7m...Supply Machine, 8, 1
2nd Seda thermometer, 9, 10...1 pressure detector, 111...differential pressure gauge.

Claims (1)

[Claims] 1 Made by crushing and calcining expansive shale in a fluidized bed pyrolysis or incinerator, true specific gravity 1.2 to 1.8, particle size Q
．． A fluidized bed pyrolysis or incineration device characterized in that an artificial aggregate of 5 mm to 3.0 mm is used as a fluidized medium.