SU1487959A1 - Packing bed - Google Patents

Description

UNION OF ADVISORS

SOCIALIST

REPUBLIN

STATE NOMINATION FOR INVENTIONS AND OPENINGS _m , 5i, „„ 1487959 (51) 4 В 01 Р 53 / 20_

G

AT GNST USSR)

DESCRIPTION OF THE INVENTION ί

TO AUTHOR CERTIFICATE (21) 4265263 / 31-26 (22) 06/19/87 (46) 06/23/89. Bull. No. 23 (71) Moscow Institute of Chemical Technology DI. Mendeleev (72) V.G. Gvozdarev, A.S. Field,

A.V. Mamaev and B “C. Golubev (53) 66.074.513 (088.8) (56) Krol E. Laboratory Manual. L .: Chemistry, 1980,

from. 407-409.

, (54) NOZZLE LAYER (57) The invention relates to the separation and deep cleaning of substances in

... packed heat and mass transfer columns and can be used for vacuum separation of thermally unstable, high-boiling substances by distillation. The aim of the invention is to reduce the height of the equivalent terretic plates, increasing throughput and lower—

On the hydraulic resistance of the column. The nozzle is filled with layers in the apparatus and each element is made in the form of a piece of tape rolled up in the shape of a Archimedes spiral. 1 s.p. f-ly, silt, 1 tab o

The invention relates to the separation and deep purification of substances in packed heat and mass transfer columns and can be used for vacuum separation of thermally unstable, high-boiling substances by their rectification.

The purpose of the invention is to reduce the height of the equivalent theoretical plate (VETT), increase the throughput and reduce the hydraulic resistance of the column.

The drawing shows an element of the proposed packed layer, axonometry.

SDBY is formed by placing bulk spiral elements in a countercurrent column, each of which is made of mesh tape and has the shape of an Archimedes spiral with the number of turns and the gap width between them according to the ratios

2D (a +, 1) + 1 = ϋ;

la N = (ϋ aD ^ (D-s)

d. _{) +} I where N and a are the number of turns and the width of the gap between them in a spiral

H and ϋ - the height and diameter of the nozzle element (spiral) ά and D - the equivalent diameter of the hole in the grid and the diameter of the wire from which it is made |

Θ is the polar angle in the system of polar coordinates, the center of which coincides with the center of the spiral of the nozzle element.

Preferably use spiral elements of the nozzle with a diameter equal to their height.

4 ^ m

with to

The packing layer in heat and mass transfer (for example, distillation) columns operates as follows. ,

When a distillation column mixture is fed (for example, from the condenser) to the top of the packing layer of a mixture of separated components in the form of a liquid, the latter, under the action of capillary forces created by the packing layer elements, is distributed over their surface in the form of a film and flows downstream of the channels randomly located in the packing layer in countercurrent to the flow of steam (or gas) supplied to these channels (for example, ^ 5 from the evaporator of the distillation column). During countercurrent movement in the packed bed of fluid and steam (gas) flows, interfacial mass transfer between the separated components is carried out repeatedly 20 between them, as a result of which one of the components is concentrated on the lower and the other on the upper end of the mass transfer column. 25 The distribution of the fluid flow under the action of the capillary forces of the elements of the packed layer on the surface of these elements in the form of a film contributes to the development of the contact surface of the phases involved in the mass transfer and the acceleration of mass transfer (reduction of HETP). The advantage of the proposed packed layer is a high degree of isotropy of its properties, affecting the hydrodynamic situation and ^ 5 the rate of interfacial mass transfer in the countercurrent column, where it is located. The latter provides a low coefficient of large-scale transition _ for VETT achieved on the proposed packed layer if it is placed in columns of different diameters. The proposed packed layer is also characterized by a large fraction of free volume, small on. ^ 5 bulk density, large specific surface area and small equivalent diameter of its constituent elements.

Example 1. From segments of a metal mesh lenu whose mesh is woven from stainless wire (X18H10T steel) with a diameter of ά = 0.08 mm and an equivalent cell diameter = 0.14 mm, elements of a loose nozzle in the form of spirals are made, 55 Archimedes. Each ele ^; the cop has a height H equal to its diameter ϋ and component 25 mm. The number of turns Ν. the tapes and the gap between them and in each element are N = 3 and 8 = 3 mm, respectively. The nozzle elements made in this way are used to determine, according to standard methods, the fraction of free volume H _st in its layer, the specific geometric surface of the nozzle, its bulk density D, equivalent diameter ά ₉ . The measurement results in comparison with similar characteristics of the nozzle used in the known method are presented in the table,

Example 2. Made according to example 1, the elements of the nozzle fill, mass transfer column with a diameter of 94 mm, in which at atmospheric pressure the process of rectification of water is carried out. In the process of rectification, the dependence of the hydraulic resistance of the layer of the irrigated nozzle on the irrigation density is removed, which determines the maximum throughput of the nozzle in relation to water. The measurements established that the maximum allowable density of the irrigation water in the proposed layer is 4100 kg / m ^z h, which is more than twice the corresponding value in the prior. The measurements provide that the flow resistance of the column during distillation of water therein when the nozzle irrigation density 1440 kg / m ch.sostavlyaet 20 kg / h m m ^g, which is approximately two times smaller than the corresponding values in the prior layer.

Example 3. In a column with a diameter of 94 mm filled with nozzle elements manufactured according to Example 1, heat and mass transfer is carried out between the liquid and vapor phases during the rectification of a benzene-toluene mixture. According to the stationary degree of separation achieved in the column, the height of the equivalent theoretical plate is determined, which at an irrigation density of 3300 kg / m ² -h is 12 cm, which is approximately 2.8 times lower than the same value in the known layer. ;

Example 4. From segments of a metal mesh tape * the mesh of which is woven from stainless wire (X18H10T steel) with a diameter of ά '= 0.08 mm and an equivalent diameter of ^{5 to} 14 rum cells <= 0.08 mm, elements of a bulk nozzle in the form of Archimedes spirals are made. Each element has a height H equal to its diameter B and component 25 mm. The number of turns N of the tape and the gap between them ά in each element is chosen according to the indicated equations, equal to Ν = 3ηΗ = 3μμ. The elements made in this way are used as nozzles for filling the mass transfer column, in which the heat and mass transfer between the liquid and vapor phases is carried out during rectification of the benzene - toluene mixture. According to the stationary degree of separation achieved in the column, the height of the equivalent theoretical plate is determined, which at an irrigation density of -g - 3300 kg / m * h is - ^ 10.5 cm.

Claims (2)

Formula ° of gain 1. The packing layer for the implementation of heat and mass transfer between phases in a countercurrent column, composed of bulk arranged spiral elements made of mesh tape, characterized in that, in order to reduce the height of the equivalent theoretical plate, increase 87959 ⁶ throughput and reducing hydraulic resistance of the column, each element of the layer has the shape of an Archimedes' spiral with the number of turns and the width of the gap. Between them, determined by the ratios 2I (a + 1) +1 = B; 2 /? A = (B a <1 B (¢ 1 + 4) П ^{ί +} (ЗД ·) 'where N and а are the number of turns and the width of the gap between them in a spiral ί 20 N and B is the height and diameter of the nozzle element (spiral) · and <1 is the equivalent diameter of the hole in the grid and the diameter of the wire from which it is made; c is the polar angle in the system of polar coordinates, the center of which coincides with the center of the helix of the element 30 of the charge. 2.- The packing layer according to claim 1, according to the fact that each element is made with a diameter equal to a height. The size of the element, mm _? from steel Kh18N10T ν _εβ m ⁵ / m ' I, kg / m ³ " m * / m <B m in the layer ----- Famous 25 Offered 25 * 25 0.43 4500 0.98 158 137 0.025 1080 0.0036