JPS626599B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a granular bituminous material, and more particularly, to a method for producing a granular bituminous material having perfectly spherical and uniform grains.

Bituminous substances such as pithu are cooled and solidified into rod-shaped,
They are handled in the form of plates or blocks, but all of these shapes have sharp corners and are prone to chipping at the corners due to frictional impact or pressure during transportation or other handling, resulting in dust generation. This has become a major occupational health problem for workers.

In order to solve these drawbacks, a method has been proposed in the past to form a bituminous material into a smooth shape without corners, that is, a spherical shape, by dropping the molten bituminous material in the form of droplets into water and solidifying it. There is.

However, the conventionally known droplet method described above has the disadvantage that the droplets are deformed by the impact when they fall into water, resulting in low commercial value. The deformation of the droplet is
This happens because the falling droplets collide with the water surface before they solidify sufficiently, so the countermeasures for this are to lower the temperature of the droplets as much as possible, or to prevent the droplets from falling into the water. Possible methods include increasing the distance between droplets and cooling the falling droplets with air. However, in the former case, there is a delicate relationship between the droplet temperature and the falling distance, and as a practical matter, it is difficult to control the temperature sufficiently to suppress droplet deformation. teeth,
The problem is the treatment of exhaust gas containing fumes of bituminous substances.

The present invention has been made in view of the above circumstances, and its gist is that molten bituminous material is made into droplets by passing through a space necessary for the material to become perfectly spherical due to surface tension, and then sprayed with water. The granular bitumen is passed through a water mist zone formed by the process to cool and solidify the surface of the droplet-shaped bituminous material, and then falls into water to solidify the entire droplet-shaped bituminous material. It depends on the method of manufacturing the substance.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

The accompanying drawings are explanatory diagrams showing an example of an apparatus for carrying out the method of the present invention. In the figure, 1 is a melting container, 2 is a heating jacket, 3 is an agitator, and 4 and 5 are an inlet and an outlet for thermal oil, respectively.

A bituminous substance such as coal tar pitch or petroleum pitch is first heated and melted in a melting vessel 1. The melting temperature depends on the softening point of the bituminous material, but it needs to be high enough that the molten bituminous material becomes perfectly spherical due to its surface tension, e.g. For bituminous material at °C,
Selected from the range of 150 to 200℃.

The molten bituminous material is introduced through the feed pipe 6 into a dispersion vessel 7 with a perforated plate 8 at the bottom and falls in the form of droplets through the pores of the perforated plate 8 in a known manner. The pore size is determined depending on the particle size of the target granular bituminous material, but is generally about 5 to 10 mm.

The droplets falling from the pores of the perforated plate 8 pass through the water mist zone 10, so that the surface thereof is cooled. The water mist zone 10 is formed by the spray water from the atomizers 9, 9' which are opposed to each other with a narrow path for the droplets to fall. It is necessary to leave a space necessary for the surface tension to form a perfect sphere. The distance of the space varies depending on the melting temperature of the bituminous material, but in the case of a melting temperature of 150 to 250°C,
Usually 10-15cm is sufficient. If the distance of the water mist zone 10 is not sufficient, the intended purpose will not be achieved, but it is not economical to make it longer than necessary, so it is generally set to about 0.5 m to 1.5 m.

The droplets that have passed through the water mist zone fall into the water in the cooling tank 11, but because the surface has been cooled and solidified in advance, it will not be deformed by impact. The droplets that have fallen into the water are completely cooled down while settling, and are taken out by a screw conveyor 12 installed at the bottom of the cooling tank 11.

In the above explanation, a method using a perforated plate was shown as a method of forming droplets of molten bituminous material, but in the method of the present invention, the method of forming droplets is not particularly limited, and the perforated plate described above In addition to the method, for example, a rotating body having a number of pins around the circumference is arranged so that the pins are in contact with the melt of bituminous material, and the melt is thrown into the air by the pins to form droplets. It is also possible to adopt a method of forming a .

According to the method of the present invention described above, it is not necessary to particularly strictly control the temperature of the molten bituminous material, and moreover, it is possible to produce granular bituminous material with perfectly spherical and uniform grains.

Next, the present invention will be explained in more detail with reference to Examples.

Example Using coal tar pitch (softening point 80° C.) as a raw material, granular coal tar pitch was produced using the apparatus shown in the attached drawings under the following conditions.

Melting temperature of raw material coal tar pitch: 180℃ Pore diameter of perforated plate: 7 m/m Distance from perforated plate to water surface: 3 m Distance from perforated plate to water mist zone (passing direction of space required to form a true spherical shape) distance): 1.5m Distance from the water surface of the water mist zone (water temperature: 25℃):
1.5m Water temperature in the cooling tank: 25℃ A predetermined amount of the obtained granular coal tar pitch (approx.
The yield of perfectly spherical particles (average particle size 3 to 5 m/m) that had not undergone impact deformation was determined to be 99%.

For comparison, granular coal tar pitch was produced in the same manner as in the example except that no water mist zone was formed and the distance from the perforated plate to the water surface was 1.5 m. I couldn't get it.

[Brief explanation of the drawing]

The accompanying drawings are explanatory diagrams showing an example of an apparatus for carrying out the method of the present invention. 1: bath melting vessel, 7: dispersion vessel, 10: water mist zone.

Claims (1)

[Claims] 1 Molten bituminous material is made into droplets by passing through a space having a distance of 10 cm or more in the passing direction necessary for the material to become a true sphere due to surface tension, and then a water mist zone formed by sprayed water. After cooling and solidifying the surface of the droplet-shaped bituminous material,
A method for producing a granular bituminous material, characterized in that the entire droplet-like bituminous material is solidified by falling into water.