CS245875B1 - Method of catalyst's particles arranged layer pouring and forming and equipment for application of this method - Google Patents

Description

The invention discloses a novel process for charging and forming an ordered layer of catalyst extrudates in a reactor for hydrogenation refining, resp. reforming the hydrocarbon mixtures and apparatus for carrying out the process.

The way in which the catalyst is poured into the interior of the reactor usually depends on the experience of operating the equipment and results from empirically established rules. A poorly deposited catalyst layer is deposited inside the reactor during use, often resulting in deformation of the reactor internals, measuring agents, reduction of heat transfer surface, change in hydrodynamic parameters of the layer, and the like. All these facts can seriously affect the reactor operating mode and control.

In small reactors, catalyst deposition can be prevented in a certain direction by vibrating during the entire reactor bed, thereby providing a catalyst bed with a higher bulk density, close to the limit, resulting from the properties and shape of the catalyst.

Of particular importance is the method of pouring the catalyst layer in large-diameter reactors, which cannot be vibrated, and in reactors where the liquid mobile phase, i.e. liquid-solid or gas-liquid-solid catalytic reactions, plays an important role.

In addition, the catalyst filling method used up to now also forms a catalyst layer under the hopper discharge opening during the charging process, terminating at the upper edge with a conical surface.

This hopper is often laboriously mechanically aligned. In addition, it is evident that even within such a layer, the conical so-called isochronous surfaces formed by the catalyst particles, simultaneously (i.e. at the moment) deposited into the reactor, are expected to exist. Therefore, in the mobile liquid phase reactors, the liquid flows to the reactor wall and creates an undesired wall flow of the reaction mixture, which creates by-pass of the catalyst layer, thereby reducing its performance.

These drawbacks are eliminated by the method of forming an ordered layer of high bulk density catalyst particles in heterogeneous chemical reaction reactors by directing a stream of falling solid particles into a circular-shaped first space and then a truncated cone terminated by a narrower base where inert gas flows, e.g. nitrogen, air or carbon dioxide, in a direction perpendicular to the particle fall direction and tangential to the annular space, the gas to volume ratio of the falling solid particles being 10 to 10,000 per unit time and the distance of the truncated cone from the upper edge The bedding layer is at least equal to the radius of the catalyst bed. The solid catalyst extrudates have a diameter of 1 to 3 mm and a length of preferably 2 to 8 mm.

The ratio of gas volume to falling particle volume is preferably maintained at 50-500 per unit time.

The apparatus for carrying out this method movable in the reactor axially by means of a jack consists of a hopper provided at the bottom with a cylindrical chamber terminated by a truncated cone with an apex angle of 30 to 150 °, preferably 30 to 60 °, which is connected to the chamber wider the chamber is provided with a concentric built-in and gas supply to two to six nozzles symmetrically located on the top periphery of the chamber.

The apparatus operates by introducing an inert gas tangentially into the cylindrical chamber in the axial direction by catalyst extrudates. The gas dispersion and catalyst extrudates are introduced into the interior of the reactor through an opening in the lower part of the cylindrical chamber.

Using the apparatus of the present invention, the catalyst particles are oriented randomly and uniformly throughout the reactor internal cross-section during the charging, thereby providing an ordered catalyst layer in the reactor. In the case of cylindrical particles, they are oriented predominantly so that their axis is horizontal. The n-laden catalyst layer is characterized by a high bulk density and a uniform free volume at all points in the reactor bed.

In this way, a given reactor volume is better utilized in comparison with the case in which the proposed device was not used for the filling of the reactor bed. For example, a smaller size reactor can be designed for the required production capacity, the redistributors of the reaction mixture flow are improved, and the efficiency of contacting the catalyst with the liquid reaction mixture is increased in the case of a mobile liquid phase system. Since it is not necessary to mechanically align the top edge of the catalyst layer in the interior of the reactor, the safety of the proposed method of charging catalyst into the reactor is increased.

The advantages of the novel process for forming an ordered catalyst bed in a reactor and the use of the proposed apparatus is illustrated by the following examples.

Example 1

Reformation Catalyst Extrusions -

The 0.5 ° / o Pt / Al ₂ O ₃ - cylindrical bore of 1.8 mm diameter and 9.4 mm mean length was sprinkled with a centrally located hopper into the 79.4 mm internal diameter reactor so that the lower edge the hopper was moved upwards during the operation to maintain a constant distance between the hopper edge and the particle layer of 95 mm. The mean apparent bulk density of the alumina layer determined by five independent experiments was 628 kg / m ³ . After the vibration of the layer due to vibration, a limit bulk density of 694 kg / m ³ was reached. Using a hopper according to the invention with a tangential air supply of two nozzles to the chamber at a rate of 1,644 l / ha, while maintaining the catalyst pouring procedure described above, a mean bulk density of 692 kg / m ³ was achieved, i.e. an increase of 10.2%. Example 2

The procedure of Example 1 was followed except that the mean length of the catalyst extrudates was 7.5 mm and the catalyst layer was poured from above 40 mm. The bulk density without air flow was 663 kg / m ³ , after damping, a density of 744 kg / m ³ was reached, and using the hopper of the present invention at different air flows, the mean bulk densities were as shown in the following table:

air flow 1 / h bulk density kg / m ³ 0 663 1 230 708 2 640 721 3 050 737 3 480 743 0 after the basement 744 increase in bulk density at the highest airflow note was 12.1 ° / o.

Example 3

1.2 kg of hydrodesulfurization catalyst of the same dimensions as in Example 2 were poured into the 159 mm internal diameter column through the central tube. at the wall of the column 110, respectively. 71 mm. The use of a feed device according to the invention at a flow of 4050 carbon dioxide resulted in a higher density catalyst bed, which was manifested by the fact that the height of the layer in the axis and / or the axis was higher. at the column wall was 89, respectively. 73 millimeters.

Example 4

Using a sprinkler according to the invention, a cylindrical vessel of 80 mm diameter was sprinkled with 530 g of the same catalyst as in Example 2. At a feed rate of 3,000 l / h, the bed volume was 740 and 740, respectively. 720 ml, if the filling time of the container was 60 resp. Without the use of a spreading device, the free-flowing catalyst bed volume was 800 ml.

Example 5

Example 1 was followed using gamma-alumina extrudates (reforming catalyst support) of 1.8 ml diameter, a mean length of 9.4 nun, which were poured into a 576 mm internal diameter reactor with the lower edge of the hopper spaced from the At the ratio of the volume of air to the volume of particulates 250, the density of the particulate layer was 654 kg / m ³ , without using the apparatus of the present invention, the alumina bulk density was 545 kg / m ³ , i.e. % less.

Claims (4)

A method for pouring and forming an ordered layer of high bulk density catalyst particles in heterogeneous chemical reaction reactors characterized in that the particle stream falls vertically downwards through a space delimited on the outside by a cylinder and truncated cone surface and comes into contact with an inert gas stream, e.g. nitrogen, air or carbon dioxide flowing in a direction perpendicular to the fall of the particles and tangential to the cylindrical shell, the gas to volume ratio of the falling particles being 10 to 10,000 per unit part and the distance of the lower edge of the truncated cone from the upper edge at least equal to the radius of the catalyst bed. 2. A method according to claim 1, wherein the solid particles have a diameter of 1 to 3 mm and a length of 2 to 8 mra. ynAlezu 3. The process of claim 1 wherein the ratio of gas volume to volume of falling particulate is maintained at 50-500 per unit time. Device for carrying out the method according to the claims 1 to 3, characterized in that it is axially displaceable in the reactor (6) in the direction of the axis by a jack (7) and consists of a hopper (1) provided with a chamber (2) of cylindrical shape, terminated by a truncated cone with an apex angle of 30 to 150 °, preferably 30 to 60 °, which is connected to the chamber (2) by a wider base, the chamber (2) being provided with a concentric built-in (3) and gas supply (4) ) into two to six nozzles (5) symmetrically located on the upper periphery of the chamber (2).