RU2411079C1 - Regular packing for heat exchangers - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to designs of regular packing intended for heat-and-mass transfer in liquid-gas system and may be used in columns for absorption and rectification in gas, oil and chemical industries. Proposed packing is made up of reticulate two-layer zigzag-like strip made from net sleeve knitted in slurs from wire. Surface of net two-layer zigzag-like strip is arranged along the gas flow direction. Net wire diametre relates to main geometrical parametres of slurs as follows:

where d is wire diametre, A is slur loop pitch equal to 7-9 mm, B is slut height equal to 6-8 mm, M is coefficient varying from 32.5 to 85.

EFFECT: reduced aerodynamic drag, higher efficiency.

5 cl, 6 dwg

Description

The invention relates to the construction of regular nozzles designed for carrying out heat and mass transfer processes in a gas (steam) - liquid system, and can be used in column apparatuses for the implementation of absorption and rectification processes in the gas, oil, chemical and several other related industries.

Known nozzle for mass transfer and separation apparatus (RU 2155095 C1, IPC B01J 19/32, B01D 45/00, 03/09/1999) containing a grid laid in layers and fixing elements made in the form of parallel rods installed in the grid and between mesh layers with a partial overlap of the nozzle section and fixing their ends with plates, while the mesh layers are installed at an angle to the rods. The rods are installed at an angle to the horizontal plane. The mesh has a zigzag profile along the length and is made of a mesh sleeve.

The disadvantage of such a nozzle is an increase in the aerodynamic drag of the nozzle due to the presence of fixing elements in the grid and between the layers of the grid, as well as the location of the surface of the grid under the angle to the direction of the gas flow. In addition, the partial overlap of the nozzle section with rods installed in the mesh and between the mesh layers reduces the specific surface of the nozzle. These disadvantages of the known device do not allow to reduce the aerodynamic drag of the nozzle and to achieve a significant increase in the efficiency of heat and mass transfer. In addition, due to the presence of fixing elements in the mesh, the mechanical strength of the nozzle decreases.

Closest to the proposed invention is a mesh nozzle for mass transfer processes (SU 403422 A1, IPC B01J 19/32, 03/30/1971), a prototype made in the form of a zigzag strip, on which a second strip of equal length is placed, located at an angle of 90 ° to front page.

The disadvantage of this nozzle is the increase in aerodynamic drag of the nozzle due to the location of the second strip of the nozzle at an angle of 90 ° to the first strip, as well as the location of the surface of the grid perpendicular to the direction of the gas flow.

The objective of the invention is to reduce the aerodynamic drag of the nozzle and increase the efficiency of heat and mass transfer.

, где d - диаметр проволоки; А - петельный шаг, равный 7÷9 мм; В - высота петельного ряда, равная 6÷8 мм; М - коэффициент, находящийся в пределах от 32,5 до 85. Кроме того, число зигзагов на 1 м длины слоя насадки составляет от 155 до 165, а угол, образуемый в местах сгиба полосы, находится в пределах от 1 до 3°.This task is achieved by the fact that the nozzle is made in the form of a mesh two-layer zigzag strip made of a mesh sleeve knitted by a smooth surface of wire. The surface of the mesh two-layer zigzag strip is located in the direction of the gas stream. The diameter of the wire mesh is in the following ratio with the main geometric parameters of the smooth surface:

where d is the diameter of the wire; A - loop step equal to 7 ÷ 9 mm; In - the height of the loop series, equal to 6 ÷ 8 mm; M is a coefficient ranging from 32.5 to 85. In addition, the number of zigzags per 1 m of the length of the nozzle layer is from 155 to 165, and the angle formed at the bend of the strip is in the range from 1 to 3 °.

, где d - диаметр проволоки; А - петельный шаг, равный 7÷9 мм; В - высота петельного ряда, равная 6÷8 мм; М - коэффициент, находящийся в пределах от 32,5 до 85, число зигзагов на 1 м длины слоя насадки составляет от 155 до 165, а угол, образуемый в местах сгиба полосы, находится в пределах от 1 до 3°.In the study of the distinguishing features of the described regular nozzle, no similar known solutions were found regarding the use of regular nozzles for heat and mass transfer apparatuses that reduce the aerodynamic resistance of the nozzle and increase the heat and mass transfer due to the correspondingly large free volume and high specific surface of the nozzle by making the nozzle in the form of a mesh a two-layer zigzag strip made of a mesh sleeve knitted by a smooth surface of wire and situated in the direction of gas flow, wherein the diameter of wire mesh is in the following relationship with the main geometric parameters kulirnoy coats:

where d is the diameter of the wire; A - loop step equal to 7 ÷ 9 mm; In - the height of the loop series, equal to 6 ÷ 8 mm; M is a coefficient ranging from 32.5 to 85, the number of zigzags per 1 m of the length of the nozzle layer is from 155 to 165, and the angle formed at the bend of the strip is in the range from 1 to 3 °.

The analysis of the prior art by the applicant, including a search by patent and scientific and technical sources of information and identification of sources containing information about analogues of the claimed invention, allowed to establish that the applicant did not find an analogue characterized by features identical to all the essential features of the claimed invention. The definition from the list of identified analogues of the prototype, as the closest in the set of essential features of the analogue, allowed to identify the set of essential distinguishing features in relation to the objective of the invention perceived by the applicant in the claimed design of the regular nozzles set forth in the claims.

The search results in order to identify signs that match the distinctive features of the declared regular nozzle from the prototype showed that the claimed invention does not follow explicitly from the prior art for the specialist, since the effects of the transformations provided for by the essential features of the claimed invention on the achievement of the above objectives of the invention have not been identified .

Figure 1 shows a regular nozzle in axonometric projection: L is the length of the layer of the nozzle.

Figure 2 - mesh sleeve (source material for the manufacture of nozzles).

Figure 3 - weaving of threads in the smooth surface: A - looped step; In - the height of the looped row.

Figure 4 is a comparison of the aerodynamic drag of the inventive nozzle and prototype Δp / H, Pa / m, on the gas flow velocity v _g m / s (experimental results of the inventive nozzle and the calculation results of the prototype).

Figure 5 shows a longitudinal section of a heat transfer column in which a regular nozzle is installed. The nozzle is fixed in the column, for example, by means of fixing elements in the form of gratings installed below and above the nozzle.

In Fig.6 is a section aa in Fig.5.

, где А - петельный шаг, равный 7÷9 мм; В - высота петельного ряда, равная 6÷8 мм; М - коэффициент, находящийся в пределах от 32,5 до 85. При этом число зигзагов на 1 м длины слоя насадки составляет от 155 до 165, а угол, образуемый в местах сгиба полосы, находится в пределах от 1 до 3°.A regular nozzle for heat and mass transfer apparatus consists of a mesh double-layer zigzag strip 1 (Fig. 1), made in the form of a mesh sleeve (Fig. 2), knitted by a smooth surface (Fig. 3) made of wire with a diameter

where A is a loop step equal to 7 ÷ 9 mm; In - the height of the loop series, equal to 6 ÷ 8 mm; M is a coefficient ranging from 32.5 to 85. In this case, the number of zigzags per 1 m of the length of the nozzle layer is from 155 to 165, and the angle formed at the bend of the strip is in the range from 1 to 3 °.

A regular nozzle in countercurrent conditions on a gas (steam) - liquid system works as follows.

The nozzle made of a mesh two-layer zigzag strip 1 (figure 1) is located in the column 2 (figure 5-6) so that the surface of the mesh two-layer zigzag strip is located in the direction of the gas flow. The liquid is evenly distributed on the nozzle from above. Gas (steam) flows from the bottom of the nozzle. The process of heat and mass transfer is carried out on the surface of the mesh two-layer zigzag strip 1, made in the form of a mesh sleeve, knitted culinary smooth surface of the wire.

The claimed regular nozzle is intended for carrying out heat and mass transfer processes in a gas (steam) - liquid system and can be used in column apparatus for the implementation of absorption and distillation processes in the gas, oil, chemical and several other related industries.

The performance of the prototype regular nozzles for heat and mass transfer apparatus, made in accordance with the claims (loop step A - 8 mm, loop height B - 7 mm, coefficient M - 50 (wire diameter d - 0.3 mm), number of zigzags per 1 m length of the nozzle layer - 160, the angle formed in the places of bending of the strip, - 2 °), confirmed by experimental tests. According to the results of our calculations, the aerodynamic drag of the inventive nozzle in the gas velocity range of 1 ÷ 4 m / s is lower than the aerodynamic drag of the prototype by 70 ÷ 90% (Fig. 4).

, где d - диаметр проволоки; А - петельный шаг, равный 7÷9 мм; В - высота петельного ряда, равная 6÷8 мм; М - коэффициент, находящийся в пределах от 32,5 до 85, число зигзагов на 1 м длины слоя насадки составляет от 155 до 165, а угол, образуемый в местах сгиба полосы, находится в пределах от 1 до 3°, заключается в снижении аэродинамического сопротивления насадки и повышении эффективности тепломассобмена за счет соответственно большого свободного объема и высокой удельной поверхности насадки.The advantage of the declared regular nozzle for heat and mass transfer apparatus, made in the form of a mesh two-layer zigzag strip made of a mesh sleeve knitted by a cooler smooth surface from a wire, and located in the direction of the gas flow, in which the diameter of the wire mesh is in the following ratio with the main geometric parameters of the smooth surface:

where d is the diameter of the wire; A - loop step equal to 7 ÷ 9 mm; In - the height of the loop series, equal to 6 ÷ 8 mm; M - coefficient, ranging from 32.5 to 85, the number of zigzags per 1 m of the length of the nozzle layer is from 155 to 165, and the angle formed at the places of bending of the strip is in the range from 1 to 3 °, consists in reducing the aerodynamic resistance of the nozzle and increasing the efficiency of heat and mass transfer due to the correspondingly large free volume and high specific surface of the nozzle.

With the values of the loop step A, the height of the loop series B, the coefficient M, the number of zigzags per 1 m of the length of the nozzle layer and the angle formed at the bend points of the strip beyond the limits specified in the claims, the following is observed:

a) not ensured sufficient mechanical strength of the nozzle:

- when the loop pitch A is less than 7 mm and the height of the loop row B is less than 6 mm;

- when the coefficient value M is more than 85;

b) significantly increases the aerodynamic drag of the nozzle:

- when the loop pitch A is more than 9 mm and the height of the loop row B is more than 8 mm;

- when the value of the coefficient M is less than 32.5;

- with the number of zigzags per 1 m of the length of the nozzle layer more than 165;

- when the value of the angle formed at the bend of the strip is less than 1 °;

c) an undesirable liquid dip occurs through the nozzle and, as a result, the efficiency of heat and mass transfer decreases:

- with the number of zigzags per 1 m of the length of the nozzle layer less than 155;

- when the value of the angle formed in the places of bending of the strip, more than 3 °.

The range of values of the loop step A, the height of the loop series B, the coefficient M, the number of zigzags per 1 m of the length of the nozzle layer and the angle formed at the places where the strip is bent, as specified in the claims, reduces the aerodynamic resistance of the nozzle and increases the heat and mass transfer efficiency with sufficient mechanical strength of the nozzle.

Claims (5)

1. A regular nozzle for heat and mass transfer apparatus, made in the form of a mesh two-layer zigzag strip, characterized in that the mesh two-layer strip is made in the form of a mesh sleeve, knitted by the cooler surface of the wire. 2. The regular nozzle according to claim 1, characterized in that the surface of the mesh two-layer zigzag strip is located in the direction of the gas stream. 3. The regular nozzle according to claim 1, characterized in that the diameter of the wire mesh is in the following ratio with the main geometric parameters of the smooth surface:

where d is the diameter of the wire; A - loop step equal to 7-9 mm; In - the height of the loop row, equal to 6-8 mm; M is a coefficient ranging from 32.5 to 85. 4. The regular nozzle according to claim 1, characterized in that the number of zigzags per 1 m of the length of the nozzle layer is 155 ÷ 165. 5. The regular nozzle according to claim 1, characterized in that the angle formed at the places of bending of the strip is within 1 ÷ 3 °.

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