JPS5930464B2 - spray tower - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement of a triple-tube spray tower used for removing dust from high-temperature, highly dust-containing gases, controlling temperature, controlling humidity, and the like.

When processing and cleaning dust-containing gas, in order to perform efficient electrostatic collection, the electrical resistance of the dust must be between 105 and 101.
It is necessary that the temperature be within the range of 1Ω, and for this purpose, a spray tower is installed in front of the electrostatic precipitator, and water vapor is blown into the dust-containing gas to raise the temperature, or water is sprayed to lower the gas temperature. It is common practice to adjust the temperature and humidity to make the electrical resistance of the dust-containing gas appropriate.

The triple cylinder spray tower has the effect of drying and removing spray water adhering to the inner surface of the inner cylinder because the gas falling between the inner and outer cylinders heats the outer surface of the inner cylinder, and also swirls the dust-containing gas between the inner and outer cylinders. It has advantages such as being able to lower the dust removal rate and increase the dust removal rate due to the centrifugal effect.

However, in conventional triple cylinder spray towers, the dust-containing gas that turns around at the bottom of the cylinder and enters the inner cylinder is in a turbulent state, and when spraying at the bottom of the inner cylinder, the spray water is generated on the inner surface of the bottom of the inner cylinder. The wall wet phenomenon cannot be avoided.

As mentioned above, the triple cylinder type spray tower has the effect of eliminating this wall wetting phenomenon on the inner surface of the inner cylinder by drying and removing it by heat transfer from the high temperature gas descending between the outer and outer cylinders, but it is not possible to prevent the wall wetting phenomenon itself. I can't.

When this wall wetness occurs, dust adheres to the inner surface of the lower part of the inner cylinder, and corrosion of the device and discharge troubles due to falling wet dust are unavoidable.

Therefore, in the conventional spray tower, it is not appropriate to spray at the lower part of the inner cylinder, and it is necessary to spray at the middle or upper part of the inner cylinder.

That is, since it is not possible to increase the residence time of sprayed water droplets in the spray tower, the temperature control and humidity control performance of the spray tower cannot be said to be satisfactory.

The present invention solves the above-mentioned problems, improves the gas flow state in the spray tower, fundamentally prevents the occurrence of wall wetting phenomenon on the inner surface of the lower part of the inner cylinder, improves temperature and humidity control ability, and sprays The purpose is to improve dust collection efficiency and reduce pressure loss in the tower.

In order to achieve the above object, the present inventor conducted numerous tests through model experiments, and as a result, completed the present invention.

The gist of the present invention is to consist of an outer cylinder and an inner cylinder that are erected on a coaxial center, and the dust-containing gas is lowered between the inner and outer cylinders, and then reversed and raised inside the inner cylinder. In a spray tower for dust removal, temperature control, and humidity control, a group of short concentric guide cylinders having a smaller diameter than the inner cylinder are arranged at the lower end of the inner cylinder so that the lower ends of the guide cylinder group form an inverted conical shape. It is located in a spray tower that features drooping.

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

FIG. 1 is a longitudinal sectional view of an embodiment of the present invention, and FIG. 2 is a view taken along the line A--A in FIG.

In the figure, 1 is a dust-containing gas inlet wind pipe, 2 is an outer cylinder, 3 is a dust hopper, 4 is a concentric guide cylinder, 5 is a support plate, 6 is a spray gun, 7 is a spray nozzle, 8 is a dust discharge device, 9
1 is an inner cylinder, and 10 is a gas outlet wind pipe.

The arrows also indicate the direction of gas flow.

The high-temperature, highly dust-containing gas introduced into the spray tower from the dust-containing gas inlet wind pipe 1 heats the outer surface of the inner cylinder 9 while blowing the inner cylinder 9.
and the outer cylinder 2, reaches the dust hopper 3, changes direction upward, and ascends inside the inner cylinder 9.

Conventionally, this direction changing section has been a mere cavity.

In the present invention, a concentric guide cylinder 4 made of a short cylinder having a diameter smaller than that of the inner cylinder 9 is disposed in this gas direction changing section.

Although one concentric guide cylinder 4 is effective, it is preferable to consist of a group of several cylinders, and the effect of improving flow rectification and dust collection efficiency tends to be greater when the number of guide cylinders 4 is large. .

On the other hand, an appropriate number is selected from the viewpoint of manufacturing.

The guide cylinder group 4 is suspended from the inner cylinder 9, and as shown in FIG. 1, the guide cylinder group 4 is arranged so that the lower ends of the guide cylinder group 4 form an inverted conical shape.

It is preferable that the inverted cone formed at the lower end of the guide cylinder group 4 be approximately similar in shape to the dust hopper 3.

Furthermore, a combination of guide cylinders in which the cross-sectional areas of the respective annular passages formed by the guide cylinders 4 are equal is appropriate from the viewpoint of the rectifying effect.

The guide cylinder group 4 functions to guide and straighten the gas flow whose direction is changed, improve dust collection efficiency, and reduce pressure loss.

FIG. 3 is an enlarged view of part B in FIG. 1, and schematically shows an example of dust particles that are separated from the gas flow and fall.

The dust particles 11 with a diameter d that descended with the gas flow are B
When the gas is reversed in the section, centrifugal force forces it out of the gas stream.

In this case, the separation speed of the particles 11 is proportional to the square of the circumferential velocity (2) of the particles having a particle diameter of 61, and is inversely proportional to the radius of curvature R of the airflow whose direction is being changed.

If the number of guide cylinder groups 4 is increased, R becomes smaller and dust collection efficiency increases.

Since the guide cylinder group 4 is arranged so that its lower end forms an inverted conical shape, the reversing gas flow is sequentially diverted from the passage formed by the dust hopper 3 and this guide cylinder group 4 to the guide cylinder group. The liquid flows into the annular passage formed by , is rectified, and rises inside the inner cylinder 9 .

Therefore, the gas inversion part and the inner cylinder 9 at the lower end of the spray tower
There is no vortex in the gas flow inside, and pressure loss is also reduced.

Furthermore, the guide cylinder group 4 allows the spray tower of the present invention to achieve a dust collection efficiency almost equivalent to that of a conventional spray tower, which collects dust by centrifugal effect by imparting swirling motion to the gas flow descending between the inner and outer cylinders.

When applying swirling motion to the gas flow descending between the inner and outer cylinders,
Although the pressure loss is extremely large, this is not necessary in the present invention, and the fan power can be significantly reduced.

Since the gas entering the inner cylinder 9 is rectified as described above, in the spray tower of the present invention, the spray gun 6 and the spray nozzle T can be provided at the lower part of the inner cylinder, and the inner cylinder 9
There is no wetting of the inner wall or dust adhesion, and there are no problems caused by corrosion of the inner cylinder or wet dust falling into the dust hopper.

Furthermore, the residence time of sprayed water droplets in the spray tower can be increased, and the temperature and humidity of the gas can be controlled efficiently.

Therefore, the temperature and humidity ranges for temperature and humidity control can be wider than before, the performance of the spray tower is increased with the same size as before, and the height of the temperature and humidity control device is increased with the same performance. It is also possible to lower the

The present invention, configured as described above, provides the following effects.

(1) High dust collection efficiency.

(2) Low pressure loss.

(3) Dogs have the ability to regulate temperature and humidity.

(4) The device can be made smaller.

Example 1 As shown in Fig. 4, the outer cylinder inner diameter is 1941 m, the inner cylinder inner diameter is 154 mm,
A concentric guide cylinder consisting of four short cylinders as shown in FIG. 5 was attached to the lower end of the inner cylinder of a model spray tower having a height of 10,641 m so as to hang down therefrom.

The diameter of each cylinder is inner diameter 134, 115.88.4, respectively.
The gas passage cross-sectional area between each cylinder was made equal to 9 mm.

As an example, a current plate shown in Fig. 6 was installed inside the lower end of the inner cylinder, and six swirl vanes were installed between the inner and outer cylinders.

The rectifying plate has a grid opening size of 30 x 30 mm and a height of 90 meters in the gas flow direction, and the swirling blade has a height of 83 m in the gas flow direction.
m, the curved blade had a circumferential advance of 60 mm from the upper and lower ends.

For this comparative example, an example showing the best dust collection efficiency and low pressure loss was selected from a large number of experimental examples, excluding the examples.

A dust-containing gas with a dust concentration of 24.3 g/Bm' was passed through a model spray tower for a certain period of time, and the dust collection efficiency was determined from the amount of dust collected.

Further, the static pressure at each point was measured using manometers 21°, 22, and 23 shown in FIG. 4, and the wind speed was measured using a pitot tube 24.

The above measurement results are shown in Table 1.

□ In addition, Figure 7 shows a sketch of the trajectory of a thread flowed to investigate the situation of streamlines.

In the figure, (I), (I), and (III) are the same as those shown in Table 1, and the thin lines indicate streamlines.

In the embodiment (If) of the present invention, compared to the conventional spray tower (I), the pressure drop is reduced, the dust collection efficiency is improved, and the gas flow state in the gas reversal section and the inner cylinder is extremely orderly. There is.

In Comparative Example (1), the dust collection efficiency is higher than in the Example, but the pressure drop increases, and there is a rectifier plate at the lower end of the inner cylinder, and a vortex is generated above the rectifier plate, so the placement position of the spray nozzle is restricted. It is undesirable.

Example 2 A concentric guide cylinder similar to that shown in Fig. 5 was attached to the lower end of the spray tower with an inner cylinder diameter of 4300 mm, resulting in an air volume of 3322 B.
The differential pressure of the induced fan is 210 mm at m'/min
Aq decreased to 2037 x 71 Aq, and the electric fan power decreased by about 3%.

In addition, the amount of spray water at the bottom of the inner cylinder is set to the maximum (0.25ra"
/min) and was able to operate without any problems.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of an embodiment of the present invention, FIG. 2 is a view along arrow A-A in FIG. 1, FIG. 3 is an enlarged view of part B in FIG. ), FIG. 5 is a side view of an embodiment of the concentric guide cylinder, FIG. 6 is a plan view of the current plate, b is a side view, and FIGS. 7 (I), (II), (1 ) are the first
FIG. 2 is a schematic longitudinal sectional view showing streamlines in the spray tower corresponding to (I), (If), and (I[I) in the table. 1... Dust-containing gas inlet wind pipe, 2... Outer cylinder, 3... Dust hopper, 4... Concentric guide cylinder, 5...・Support plate, 6...Spray gun, 7...Spray nozzle, 8...
・Dust discharge device, 9... Inner cylinder, 10...
・Outlet gas wind pipe, 11... Dust particles, 12...
...-straightening plate, 13...swivel vane, 21,2
2, 23... Manometer, 24... Pitot tube, 25... Streamline.

Claims (1)

[Claims] 1 Consisting of an outer cylinder and an inner cylinder with a coaxial core, the dust-containing gas is lowered between the outer and outer cylinders, then reversed and raised inside the inner cylinder,
In the spray tower that performs dust removal, temperature control, and humidity control of the dust-containing gas, a group of short concentric guide cylinders having a smaller diameter than the inner cylinder diameter is formed at the lower end of the inner cylinder, and the lower end of the guide cylinder group forms an inverted conical shape. A spray tower characterized by hanging down in an array.