SU405238A1 - - Google Patents

Description

one

The invention relates to devices for producing granulated products (such as ammonium nitrate, urea, etc.) from melts of these substances by solidifying melt drops in countercurrent with cooling air. And can be used in the chemical and other industries.

A device for granulating substances from their melts is known, comprising a vertical column, in the upper part of which a melt distributor with a perforated bottom is installed, and in the lower part there are several partitions made in the form of alternating forward and reverse cones, under which a bunker is installed to receive the granular product. The product melt is continuously supplied from the pressure tank to the distributor, and cooling air is passed through the column cavity from the bottom up. The melt streams flowing out of the holes in the perforated bottom of the distributor fall into droplets, which, when freely dropped in the counter flow of cooling air, solidify from the surface and, falling on the conical partitions, roll over these partitions from one to another, changing the trajectory of movement and reducing the speed of their fall. . At the same time, for curing, the height of the free fall of droplets, and

hence the height of the column can be reduced.

However, in a well-known apparatus it is impossible to achieve a significant reduction in the height of the column due to the fact that it is limited to the minimum allowable value at which the destruction of insufficiently solidified granules has not yet been observed.

In order to reduce the height of the column, the proposed apparatus is equipped with a screw blade located above the partitions and mounted on the rotation drive shaft in the direction opposite to the winding direction of the blade.

Due to the presence of a vipta blade rotating in the direction opposite to its winding direction, when the granule falls, the force of its impact on the blade surface decreases significantly, as a result of which

the theoretically required height of the fall of the granules and, accordingly, the height of the granulation column.

The drawing shows schematically the proposed device.

It consists of a vertical column 1, in the upper part of which is installed the distributor 2 of the melt with a perforated bottom 3 and a visor 4, intended to enclose the airspace located

iodine perforated bottom

cold air to the bottom surface and cooling of the zone located by it. Inside the column on the shaft 5, a cylindrical nozzle 6 with an internal screw lonest 7 is strengthened. Under the nozzle 6, central 8 and lateral 9 co-partition partitions are installed, and below the non-suburbs there is a bunker of granules (not shown in the drawing).

Rasnlav ammonium nitrate or urea through the pipe 10 served in the distributor 2, and using nozzles 11 inside the column sprayed fine powder of talc or other substance with cold dried air. A shaft 5 with a blade 7 is driven into rotation in the direction shown by arrow A. Melt jets flowing out of the holes of the perforated bottom 3 of the distributor 2, fall into canals, which are intensively powdered from the surface with particles of powder sprayed by nozzles 11 and washed with cold air. In this case, the droplets begin to crystallize intensively from the surface, forming a hard shell, and fall onto the blade 7, which rolls over the partitions 8 and 9, and then into the granule cooler receiving hopper. At the same time, due to the rotation of the blade in the direction opposite to the direction of its winding, forces occur at elementary parts of its surface at the moment of contact of the granules, due to the rotation of the blade, the normal components of which are directed against the normal components of the gravitational forces causing the force of impact of the drop on the surface. Thus, the total normal component of the force acting on each granule at the moment of impact on the surface decreases, and the impact of the granules on the surface softens. With an increase in the speed of rotation of the blade, the degree of impact reduction increases.

And so, in the proposed apparatus, the granules are transferred from the path of free fall much earlier and with a less strengthened surface crystallized shell than in the known. This significantly reduces the free-fall time for droplets.

Subject invention

A melt pelletizing apparatus containing a vertical column, a product sprinkler, an insertion device

cooling agent and partitions made in the form of alternating direct and reverse cones installed one above the other, characterized in that, in order to reduce the height of the column, the apparatus is equipped with a helical blade located above the partitions and mounted on the rotary drive shaft in the opposite direction the direction of the winding blade.

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