RU2370311C1 - Packing for mass-transfer apparatus - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention refers to design of damp packing of mass-transfer apparatus and can be implemented in chemical, oil processing, petrochemical and other branches of industry in heat-, mass-transfer processes in systems liquid-steam(gas), for example in rectification, absorption, desorption, distillation and other processes. Packing for mass-transfer apparatus is made in form of a hollow cylinder with turbulising components. Turbulising components are made in form of open channels arranged on internal and external surfaces of the cylinder; the channels are arranged along screw lines. Also a pitch of the screw line does not exceed height of the cylinder, while ratio of packing diametre to its height is 1-4. Not only external, but additional internal open channels arranged along screw lines facilitate generating screw flow in the layer of the packing on external and internal surfaces; when these two flows intersect at transition from one packing to another it creates additional local turbulences of liquid and gas flows and improves inter-phase mixing.

EFFECT: increased efficiency of mass-transfer and reduced hydraulic resistance.

3 cl, 2 dwg

Description

The invention relates to the design of bulk nozzles for mass transfer apparatuses and can be used in chemical, oil refining, petrochemical and other industries when performing mass transfer processes in liquid-vapor (gas) systems, for example, rectification, absorption, desorption, distillation and other processes.

Known element nozzles for mass transfer apparatuses, which are a ring without additional devices, (see Ramm V.M. "Absorption of gases." Ed. 2nd revised and additional - M .: "Chemistry", 1976, p.313 )

The closest set of essential features is the nozzle for mass transfer apparatus, made in the form of a hollow cylinder, with turbulence elements located on its outer surface in the form of open channels located along a helical line (see Patent No.RU 2280492, IPC B01D 47/14, B01D 53/18 2006).

The disadvantages of these nozzles is the lack of mass transfer efficiency and high hydraulic resistance.

The objective of the invention is to create the design of the nozzle, which allows to increase the efficiency of mass transfer and reduce hydraulic resistance by changing the surface profile of the interface.

This task is achieved due to the fact that the nozzle for mass transfer apparatus, made in the form of a hollow cylinder, with turbulence elements located on its outer surface in the form of open channels located along a helical line, according to the invention, the nozzle is additionally equipped with a helical line located on the inner surface cylinder turbulent elements in the form of open channels.

The pitch of the helix is not more than the height of the cylinder and the ratio of the diameter of the nozzle to its height is made in the range of 1-4.

In Fig.1 schematically shows the nozzle, a General view in section, in Fig.2 is a view of the nozzle from the top in Fig.1.

The contact device is a hollow cylinder 1 with external 2 and internal 3 open channels located along helical lines.

The nozzle for mass transfer apparatus works as follows.

To conduct the technological process, the necessary volume of the apparatus is filled in bulk with nozzle elements. The contact between mass-exchanging flows (liquid-gas) occurs continuously in countercurrent along the entire height of the nozzle layer on both the external and internal surfaces. Irrigating liquid is evenly distributed over the surface of the nozzle layer and flows down the elements. Gas is supplied through the switchgear from the bottom of the apparatus and moves up. The presence of the nozzle not only external 2, but also additional internal 3 open channels located along helical lines with a pitch of not more than the height of the cylinder, will increase its free volume and internal surface, i.e. to increase the contact surface of the interacting phases, which will lead to the intensification of the mass transfer process, and also contributes to the formation of a screw flow in the nozzle layer not only on the external but also on the internal surfaces, and the intersection of these two flows during the transition from one nozzle to another creates additional local fluid vortices and gas flows, the best conditions for interfacial mixing, i.e. enhances turbulization and increases the frequency of updating the contact surface of interacting phases, which leads to an increase in mass transfer efficiency and a decrease in hydraulic resistance.

The simultaneous arrangement of turbulent screw channels on both the external and internal surfaces of the cylinder will lead to the nozzle self-orienting towards the contacting flows when loading into the bulk due to the fact that while the fluid in the apparatus being in contact with the nozzle is twisted, it is inundated while loading approximately 80% of the nozzle is aligned with the flow, resulting in an increase in the throughput of the nozzle and its specific surface, which leads to an intensification of the mass process exchange and reduce hydraulic resistance.

When the step of the helix is not more than the height of the cylinder, the turbulization of the interacting phases increases, that is, the mass transfer efficiency increases, while the hydraulic resistance decreases at the same time due to the helical movement on the external and internal surfaces of the flows.

The minimum value of the helix pitch is 5 mm, i.e.: 0.1 of the cylinder height with a nozzle height of 50 mm, 0.05 of the cylinder height with a nozzle height of 100 mm.

When the pitch of the helix is less than 5 mm, the mass transfer efficiency sharply decreases due to the film being torn off the nozzle surface, which is unacceptable.

The implementation of the nozzle with a ratio of its maximum diameter to height within 4-1 ensures the self-orientation of the nozzle when loading in bulk, that is, it reduces hydraulic resistance and creates a developed specific surface, leading to an increase in mass transfer efficiency.

When the helix pitch is greater than the height of the cylinder, the mass transfer efficiency sharply decreases due to the reduction of the channel length, which is unacceptable.

When the ratio of the maximum nozzle diameter to its height is less than 1, the specific surface of the nozzle is reduced when it is randomly loaded into the apparatus. When the ratio of the maximum nozzle diameter to its height exceeds 4, the hydraulic resistance increases, which is unacceptable.

The test results of the nozzle element for mass transfer are given below.

Example 1

The nozzle was made in the form of a hollow cylinder 1 with the following dimensions: height H = 50 mm, diameter D = 50 mm, thickness 8 = 5 mm.

The channels on the outer 2 and inner 3 surfaces are located along single-helix lines. The pitch of the helical lines is p on the outer and inner surfaces of 6.5 mm, the depth of the channels is 2.5 mm.

During testing, the nozzle was loaded into the column 0.6 m in diameter, the layer height was 1 m. The loading of the nozzle into the column showed that 80% of the nozzle fit in flow.

After conducting hydraulic tests at an irrigation density of 0 and a gas velocity of 2 m / s, a pressure loss of 43.2 mm of water was obtained. senior / linear meter, which is 1.4 times smaller in comparison with the Rashig rings of size 50 × 50 × 5, and 1.14 times compared with the prototype.

With an irrigation density of 10 m ³ / (m ² * h) and a gas velocity of 2 m / s, the hydraulic resistance of the nozzle is 2.7 times less compared to Rashig rings 50 × 50 × 5 and 1.3 times compared with the prototype, and the mass transfer coefficient increases by 11% compared with the prototype.

Example 2

The nozzle was made in the form of a hollow cylinder 1 with the following dimensions: height H = 12.5 mm, diameter D = 50 mm, thickness S = 5 mm.

The channels on the outer 2 and inner 3 surfaces are located along single-helix lines. The pitch of the helical lines is p on the outer and inner surfaces of 5 mm, the depth of the channels is 1.5 mm.

During testing, the nozzle was loaded into the column 0.6 m in diameter, the layer height was 1 m. The loading of the nozzle into the column showed that 80% of the nozzle fit in flow.

After conducting hydraulic tests at an irrigation density of 0 and a gas velocity of 2 m / s, a pressure loss value of 30.1 mm water was obtained. senior / linear meter, which is 2 times smaller compared to Rashig rings 50 × 50 × 5 in size, and 1.6 times compared to the prototype.

With an irrigation density of 10 m ³ / (m ² * h) and a gas velocity of 2 m / s, the hydraulic resistance of the nozzle is 3.8 times less compared to Rashig rings 50 × 50 × 5 and 2.2 times compared to the prototype, and the mass transfer coefficient increases by 23%, compared with the prototype.

The invention allows to reduce hydraulic resistance and increase the efficiency of mass transfer due to the implementation of turbolizing elements in the form of open channels located along a helical line, and the pitch of the helical line is not more than the height of the cylinder and the ratio of the diameter of the nozzle to its height is made within 1-4.

1. Ramm V.M. "Absorption of gases." Ed. 2nd rev. and add. - M., Chemistry, 1976.656 s.

2. Patent RU 2280492, IPC B01D 47/14, B01D 53/18 2006

Claims (3)

1. The nozzle for mass transfer apparatus, made in the form of a hollow cylinder with turbulence elements located on its outer surface in the form of open channels located along a helical line, characterized in that it is additionally equipped with turbulence elements located along a helical line on the inner surface of the cylinder in the form of open channels. 2. The nozzle according to claim 1, characterized in that the ratio of the diameter of the nozzle to its height is 1-4. 3. The nozzle according to claim 1, characterized in that the helical pitch of the open channels does not exceed the height of the cylinder.

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