Coned Sieve-Grid Tray Field of Technique The present invention concerns a coned sieve-grid tray for the intensification of the process of oxidation in the production of bitumen as well as productions involving highly viscous products in the oil processing, oil chemistry and other fields.

Prior art Various types of trays are known: bell trays with a sealed, dismountable or tunnel bell ; grid trays discharging the absorbent, which are of grate, grid, gap, net and pipe type.

A shortcoming of all these trays is their inapplicability with highly viscous products, because they do not sufficiently assure the contact between the two phases, have a low level of safety when used with air mixtures, and have a high level of coke formation, which is a result of the high temperature and the retention of the product on the surface of the tray. These conventional trays also fail to solve the problem with the smooth flow of the chemical reaction and the mixing of oxidized and non-oxidized bitumen in the zone under the tray.

Summary of the Invention Accordingly, the aim of the present invention is to remove the shortcomings of the existing trays by increasing the intensity of the flow of the chemical reaction of oxidation and assuring a layer-like flow of the liquid without retention of the product on the surface of the tray as well as by improving the mixing of oxidized and non oxidized bitumen in the zone under the tray.

The aim is achieved by the creation of a coned sieve-grid tray, which includes a supportive construction, on which a perforated plate is fixed. Characteristic for the tray is that the plate has the shape of a truncated cone and the perforation is performed in such a manner that passing openings, spaced at a certain distance, are obtained. The walls of the passing openings are angled to the

plane of the plate. The opening at the smaller base of the truncated cone could have a different geometry and is attached to a support that is connected to supportive beams.

It is suitable for the opening at the smaller base of the truncated cone to have a rectangular geometry.

In one variant of accomplishment, the openings are introduced in the peripheral zone of the big base of the truncated cone, spaced evenly at a certain distance from the edge of the perforated plate.

In another variant of accomplishment of the tray the passing openings have a rectangular cross-section.

In another variant of accomplishment the passing openings have a circular cross-section.

In another preferred variant of accomplishment the passing openings have an oval cross-section.

In another variant of accomplishment the passing openings have a S-shaped cross-section.

It is suitable for the walls of the passing openings to be located on both sides of the perforated plate.

The advantages of the sieve-grid tray according to the invention lay in the provision of a layer like flow of the reagents through the passing openings due to the specific allocation of the walls of these openings angled to the plane of the tray. This results in the intensification of the flow of the reactions, while simultaneously no oxidized bitumen is being retained and no coke is formed on the surface of the tray. Due to the combination of an exit opening at the small base the truncated cone and the specific shape of the passing openings, a complete mixing of the oxidized and non-oxidized bitumen in the zone under the tray is provided. This effect is mostly pronounced in the variant of accomplishment that has additionally introduced openings in the peripheral zone at the big base of the cone-like plate.

Description of attached drawings Figure 1 shows a cross-section of the coned sieve-grid tray according to the invention; Figure 2 is a top view of the tray; Figure 3 illustrates a variant of accomplishment of the tray in which the walls of the passing openings are located from both sides of the perforated plate.

Examples for particular realization The coned sieve-grid tray (fig. 1) includes the supportive construction 1 on which a perforated plate 2 is fixed, which has the shape of a truncated cone. The perforation on plate 2 has been done in such a manner that passing openings 3, spaced at a certain distance, are obtained. These openings can have a rectangular, circular, oval, S-shaped or any other suitable cross-section. The walls 4 can be located on both sides of plate 2 (fig. 3). Opening 5 at the small base of the truncated cone can have various shapes, while plate 2 is attached to support 6, equipped with supportive beams 7. In the preferred variant of accomplishment opening 5 has a rectangular shape, which is best shown on figure 2.

In the peripheral zone at the big base of the truncated cone openings 8 are formed, evenly spaced at a certain distance from the edge of the perforated plate 2. The coned sieve-grid tray, according to the invention, functions as follows : Two or more fluids F1, F2, while passing through the openings 3 of the tray, are headed in opposite directions, which serves for the maximal interaction during the processes of heat and mass exchange. Due to the angled allocation of walls 4 of the passing openings 3, an even redistribution of the velocities of the reacting products as well as the transformation of the turbulent current into laminar is obtained. Thus, the mass current is transformed into a current of the

separate layer streams, which increases the contact surface and the intensity of the reaction.

The oxidation of the bitumen is performed through the passing openings 3, while the bitumen that is not subjected to oxidation passes through the openings 5 and 8 of the tray, while the mixing of oxidized and non-oxidized bitumen is performed in the zone under the tray.