RU190583U1 - Ring-shaped nozzle for heat and mass transfer processes - Google Patents

Abstract

The ring-shaped nozzle, made from a strip of a rectangular billet, the opposite ends of which are interconnected with rotation 180 ° relative to each other, is intended for use in devices of chemical technology, industrial ecology and energy. The blank strip is bent in half, forming a V-shaped profile in its cross-section, which allows increasing the mechanical strength of the nozzle elements. As a result, it is possible to prevent wrinkling of the elements of the nozzle and, in general, to reduce the bulk weight of the proposed nozzle. Performing elements of the annular packing from a blank strip with a rectangular shape with a ratio of the height of the packing element H to the length of the blank strip L ranging from (H / L) = 0.11 to (H / L) = 0.04 can increase the efficiency of heat and mass transfer processes due to the maximum use of the so-called "end effects". All other things being equal, with a decrease in the height of the nozzle element H from 15 mm to 5 mm, the mass transfer coefficients increase significantly.

Description

The ring-shaped nozzle for heat and mass transfer processes is intended for use in chemical technology, industrial ecology and energy equipment.

Known nozzle, made in the form of Raschig rings, in which the height is equal to the diameter (see Sokol BA, Chernyshev AK, Baranov DA and others. Nozzles of mass transfer columns // Ed. By DA Baranov M. 2009 358 p.)

The disadvantage of this nozzle when loading it into the apparatus is that it mainly fits so that from% to% of the elements of this nozzle are oriented either horizontally or at a small angle to the horizontal plane. Therefore, the internal cavity of these elements of the annular packing is practically not bathed by interacting gas and liquid streams, which significantly reduces the efficiency of heat and mass transfer processes (see Kagan AM, Laptev AG, Pushnov AS, Farakhov M.I. Contact nozzles of industrial heat and mass transfer apparatus. Kazan: Fatherland, 2013. 454 p.).

The closest technical solution to the proposed (prototype) is a ring-shaped nozzle, made of a rectangular strip, the opposite ends of which are interconnected with rotation 180 ^o relative to each other (see USSR Author's Certificate No. 631185, cl. B01D 53/20). This ring-shaped nozzle allows you to reduce the disadvantage noted above and increase the washability of the inner surface of the nozzle elements. However, the mechanical strength of the elements of this nozzle is insufficient and, when loaded into large-height industrial column apparatus, some of the elements of such an attachment, located in the lower tier of the column apparatus, are crushed, which adversely affects the hydrodynamics of the technological process.

To eliminate this drawback, it is proposed to make an annular nozzle from a strip of a rectangular billet, bent in half, forming a V-shaped profile in its cross section. This allows you to increase the mechanical strength of the elements of the nozzle and to prevent their crushing in industrial column devices of great height.

The implementation of the elements of the annular nozzle from the strip of a rectangular billet with the value of the ratio of the height of the elements of the nozzle - Hp to the length of the strip of the workpiece - L in the range of (H _p / L) = 0.11 to (H _p / L) = 0.04 allows you to increase efficiency processes of heat and mass transfer by 18 ÷ 24%.

A general view of the proposed annular packing is shown in FIG. 1. In FIG. 2 shows the strip of the workpiece 1, bent in half. The proposed annular nozzle is made of a strip of billet 1 of a rectangular shape. The length of the strip of the workpiece 1 is equal to L mm, and the height of the element of the nozzle is H _p mm (see Fig. 2).

The results of hydrodynamic tests of the proposed packing with different irrigation densities Q and _{W are} presented as dependency graphs (ΔP / H) = f (W ₀ ) in FIG. 3. Here (ΔP / H) is the relative hydraulic resistance of the nozzle layer ΔP calculated on the height of the layer H = 1 m, Pa / m. W ₀ is the gas flow velocity calculated on the total cross-section of the empty apparatus, m / s. Figures 2 ÷ 7 in FIG. 3 shows data for the following irrigation densities:

2 - Q _OK = dry nozzle 3 - Q _W = 5 m ³ / (m ² h) 4 - Q _W = 10 m ³ / (m ² h) 5 - Q _W = 14 m ³ / (m ² h) 6 - Q _W = 19 m ³ / (m ² h) 7 - Q _W = 24 m ³ / (m ² h)

The proposed nozzle has a unique property of self-orientation, when loading into a pile, which provides minimal hydraulic resistance, good washability of the inner surface and high efficiency of the process.

The implementation of the annular nozzle of a rectangular strip bent in half, forming in its cross section a V-shaped profile allows you to increase the mechanical strength of the elements of the nozzle while using thin metal sheets for their manufacture. As a result, it is possible to prevent the collapse of the elements of the nozzle located in the lower tier of the column apparatus with the nozzle and, in general, to reduce the bulk density of the proposed nozzle.

The implementation of the elements of the annular nozzle from the blank strip of rectangular shape with the value of the ratio of the height of the nozzle element - H _p to the length of the blank strip - L in the range from (H _p / L) = 0.11 to (H _p / L) = 0.04 allows you to increase efficiency of heat and mass transfer processes due to the maximum use of the so-called "end effects". Within the specified limits of variation of the value (H _p / L), all other things being equal, when the process speed is limited by mass transfer in the liquid phase, with a decrease in the height of the nozzle element H _p from 15 to 5 mm, the mass transfer coefficients increase significantly. However, at H _p <5 mm, due to a significant increase in the number of end effects, the degree of turbulence in the gas flow significantly increases and the hydraulic resistance of the packing layer sharply increases.

On the contrary, with an increase in the height of the nozzle elements H _p > 15 mm, the hydraulic resistance of the nozzle layer decreases, but the increase in the efficiency of the technological process also drops markedly.

Geometric characteristics of the proposed nozzles are presented in table 1.

Table 1.

Geometric characteristics of the proposed nozzle

No. p / p Dimensions of nozzle elements, mm Specific surface a, m ² / m ³ Porosity ε, m ³ / m ³ Equivalent channel diameter of the nozzle d _e , m The number of elements of the nozzle in V = 1 m ³
N pcs / m ³ one 50 × 15 × 0.2 160 0.9878 0.025 37700 2 50 × 10 × 0.2 170 0.9863 0.023 59400 3 50 × 5 × 0.2 179 0.9848 0.022 123,000

Claims (2)

1. Ring-shaped nozzle for heat and mass transfer processes, made of a rectangular billet strip, the opposite ends of which are interconnected with rotation 180 ° relative to each other, characterized in that the rectangular billet strip is bent in half, forming in its cross section V-shaped profile. 2. Annular nozzle under item 1, characterized in that the ratio of the height of the elements of the nozzle H _p to the length of the workpiece strip L is in the range from (H _p / L) = 0.11 to (H _p / L) = 0.04 .

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