RU2580727C1 - Vortex evaporator-condenser - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: invention relates to heat and mass transfer devices. Vortex evaporator-condenser, consisting of vertical cylindrical housing with cover and bottom, process unions, heat carrier feed and discharge chambers, cylindrical pipes equipped with fluid distributors and internal tubes, on whose surface there are through channels to side edges of which is tightly attached shaped plate installed in guides washers that form swirlers to provide rotary translation vapor (gas) arranged along height of cylindrical tubes, characterised by that under each swirler support washers are provided with channels for coolant draining, ratio of inner diameter of bearing disc d to cylindrical tube inner diameter D is equal to d/d=0.6-0.9, and in guide washers are made through shaped holes for gas (vapour) movement in axial direction, ratio of distance between two adjacent support washers L to rotary column height for gas-liquid layer H is equal to L/H  1 Η value is equal to

H is height of gas-liquid layer, m, h is height of channels in swirler, m; φ-gas content (fraction of gas in liquid), D_st is diameter of cylindrical tube, m, R_zav is swirler radius, m, u_g is speed of gas in channels of swirler, m/s, m is weight of rotating water (liquid), kg.

EFFECT: technical result is high efficiency.

1 cl, 5 dwg

Description

The invention relates to heat and mass transfer apparatuses and can be used as condensers, evaporators, heaters, reflux condensers, evaporators in the petrochemical, chemical, microbiological, food and other industries.

Known film evaporator with a flowing film, consisting of a vertical cylindrical body with a lid and a bottom, equipped with technological fittings, a heating chamber and chambers for input and output of concentrated solution, secondary steam, pipelines for input and output of refrigerant, cylindrical and inner pipes, pipes for condensate discharge of secondary steam. In the cavity of cylindrical pipes along their length with a gap relative to the surface of the cylindrical and inner pipes, shells are installed, in the lower part of which plates are placed on their outer surface at an angle to the axis of the apparatus, providing rotational movement to the steam flow [1].

However, this apparatus has a relatively low productivity, due to the low values of the heat transfer coefficient achieved in the film flow, which is 2-4 times lower than in heat transfer in a rotating layer [2]. The presence of the plates creates a rotational movement only to the flow of steam (gas), but does not provide the rotational movement of the liquid on the heat transfer surface and, therefore, does not intensify the heat transfer enough.

The closest to this design in technical essence is a film evaporator with a falling film [3], consisting of a vertical cylindrical body with a lid and a bottom, equipped with technological fittings and chambers for the input and output of a concentrated solution, a heating chamber, pipelines for introducing and removing refrigerant condensate drainage of secondary steam. The apparatus is equipped with nozzles, cylindrical pipes with an annular spiral and a distribution element for irrigation and internal pipes made in the form of a coil. In the annular cavities formed by the cylindrical and inner pipes, guide washers are installed, between which profiled plates are placed that form channels for the passage of the vapor-liquid mixture, in which one of the side edges is placed tangential to the inner surface of the washer, and longitudinal grooves and a sheet of porous material is installed.

However, this device does not allow to ensure high productivity of the apparatus due to the relatively low values of the heat transfer coefficient from the side of the falling liquid film in the same way as in the apparatus taken as an analog. The presence of washers with profiled plates that form tangential swirls also does not provide rotational movement of the fluid layer on the heat transfer surface (the shear stresses of the friction force between the vapor (gas) flow and the fluid are insufficient to create a rotating layer on the heat transfer surface), which does not provide complete irrigation (wettability) of the heat transfer surface by a liquid film at high heat fluxes, i.e., the appearance of dry, non-wetted areas on the heat transfer the surface, as well as folding the film into bundles and jets, which is ineffective. At high flow rates of steam (gas), rotational-translational movement of the film is provided (ascending or descending forward flow), which, as already shown earlier [2], does not provide intensive heat transfer.

The invention solves the problem of increasing productivity in terms of specific heat load (heat flux Q per unit surface F, q = Q / F, W / m ² ), and therefore also in terms of evaporated moisture by ensuring stable rotation of the gas-liquid layer.

Sustainable rotation is understood as the complete irrigation (wetting) of the surface and the pressing of the rotating fluid layer to the heat transfer surface by inertia and pressure on the liquid by steam (gas) jets leaving the swirler channels. It should be noted that in the inventive device, the rotation of the liquid is provided not by the tangential stresses of the friction forces between the rotating flow of steam (gas) and the liquid, but by acting on the incompressible liquid placed on the supporting washers, the inertia force and the dynamic pressure of the jets.

The technical result is to increase productivity by ensuring stable rotation of the gas-liquid layer. The rotating gas-liquid layer on the heat transfer surface is provided by the inertial (centrifugal) force and the dynamic pressure of the gas jets (steam) emerging from the swirler channels, displacing the mass of liquid placed on the supporting washers up to a height N and providing rotation of this liquid due to twisting of the liquid volume, placed on the supporting washers, and not due to the friction forces between the gas and the falling film, as this is partially ensured by ascending or descending forward flow, which causes intensive rotation of the liquid spine at low cost steam (gas) and high heat transfer intensity.

The specified technical result is achieved in that in a vortex evaporator-condenser, consisting of a vertical cylindrical body with a cover, a bottom and technological fittings, chambers for the input and output of coolants, cylindrical pipes equipped with liquid distributors, and internal pipes, on the surface of which through channels are made , to the lateral edges of which profiled plates are mounted tightly, mounted in guide washers, forming swirlers placed along the height of cylindrical t UB to ensure the rotational movement of steam (gas), according to the invention, a support washer is installed under each swirl equipped with channels for the flow of coolant, and in the guide washers there are through profiled holes for the passage of steam (gas) in the axial direction, the ratio of the inner diameter of the support washer to the inner the diameter of the cylindrical pipe is d / D = 0.6-0.9, and the ratio of the distance between the two support washers L to the height of the column of the rotating gas-liquid layer H is equal to

The presence of support washers installed under each swirl, in which channels are made for the flow of coolant from one support washer to another, as well as the execution of through profiled holes in the guide washers to move the vapor (gas) in the axial direction, which allows a rotating gas-liquid layer on the surface of cylindrical pipes due to the displacement of the liquid placed on the supporting washers by gas jets and centrifugal force, which ensures complete irrigation (wettability) of the heat transfer surface At high heat loads and intensifies the heat transfer process.

The presence on the supporting washers of channels (slots, profiled holes) allows you to distribute the coolant among the supporting washers and, thereby, provides irrigation of the entire surface of the cylindrical pipes.

The presence of through profiled holes on the guide washers allows the steam (gas) to move freely in the axial direction, thereby providing intensive rotation and heat removal at high heat loads.

The ratio of the inner diameter of the support washer to the inner diameter of the cylindrical pipe, equal to d / D = 0.6-0.9, allows you to create a given thickness of the rotating gas-liquid layer. At a ratio d / D <0.6, the angular velocity of rotation of the liquid decreases due to an increase in its mass on the support washer, and at d / D> 0.9, surface irrigation is not ensured, which in both cases leads to a decrease in heat transfer, and, consequently, and performance.

Fulfillment of the ratio of the distance between the two support washers L to the column height of the rotating gas-liquid layer H equal to L / H≤1 allows for complete irrigation of the heat transfer surface (gas-liquid layer H completely moistens the heat transfer surface), which allows to increase productivity in specific heat load.

The calculated dependence for determining the value of H was obtained based on the balance of forces acting on the rotating gas-liquid layer

where F is the force caused by the pressure of the column of the rotating gas-liquid layer;

F _in - the force of inertia from rotation;

F _din - the force caused by the pressure of the jets of gas (vapor) emerging from the channels of the swirler.

H - the height of the gas-liquid layer, m;

h is the height of the channels in the swirl, m;

φ - gas content (gas fraction in the liquid);

D _c - the diameter of the cylindrical pipe, m;

R _zav - swirl radius, m;

and _g is the gas velocity in the channels of the swirler, m / s;

m is the mass of rotating water (liquid), kg;

w is the angular velocity of rotation, s ^-1 ;

ρ, ρ _g - respectively, the density of the liquid and gas, kg / m ³ .

After the conversion, we have

where χ is the surface coefficient.

In FIG. 1 shows a general view of an evaporator-condenser;

In FIG. 2 shows part of a cylindrical and inner pipe;

In FIG. 3 shows a section of a cylindrical pipe along section AA;

In FIG. 4 shows a section of a cylindrical pipe along section BB;

In FIG. 5 is a flow distribution diagram.

The vortex evaporator-condenser consists of a vertical cylindrical body 1, equipped with a cover 2 and a bottom 3, technological fittings for introducing 4 steam (gas) and 5 steam (vapor-gas mixture), fitting 6 for introducing process steam and fitting 7 for condensate drain, as well as fittings 8 and 9 for the input and output of the coolant (water). The apparatus is equipped with chambers 10 for introducing process steam and outputting coolant 11, cylindrical pipes 12 with openings for introducing coolant (water) 13 and liquid distributor 14. The apparatus is also equipped with inner pipes 15, muffled from above, on the surface of which through channels 16 are made, to the side the edges of which are profiled plates 17 tightly mounted in the guide washers 18 and 19, forming swirlers 20 to provide rotationally translational movement of steam (gas), placed along the height of the cylinder tubes 12. Under the swirls 20 on the inner surface of the cylindrical pipes 12, support washers 21 are installed at a distance L, provided with channels 22 (holes) for draining the coolant. In the guide washers 18 and 19, profiled holes 23 are made for moving the vapor (gas) in the axial direction of the cylindrical pipes.

The diameter of the cylindrical pipes is 28-500 mm.

Vortex evaporator-condenser operates as follows. The coolant (water) through the nozzle 8 is supplied to the apparatus and distributed on the upper tube sheet, then through the holes 13 and the liquid distributor 14 enters the inner surface of the cylindrical pipes 12 and flows onto the supporting washers 21. Steam (gas) enters the apparatus through the nozzle 4 and distributed through cylindrical pipes 12, enters through channels 16 and then into swirls 20. At the outlet of swirls 20 channels formed by profiled plates 17, steam (gas) acquires rotational motion and high-speed pressure. As a result, gas jets and inertia caused by rotation displace the liquid placed on the supporting washers 21 in the form of a gas-liquid layer to a height H, ensuring its rotation and pressing against the inner surface of the cylindrical pipes 12. The boiling of the rotating gas-liquid layer is ensured by the heat flow, supplied through the wall of cylindrical pipes 12, caused by steam entering the apparatus through the nozzle 6 into the chamber 10. The coolant flows onto the supporting washers 21 through the channels 22, and then enters the chamber 11 and through the nozzle 9 discharged from the apparatus. The steam formed during boiling is mixed with the steam (gas) entering through the nozzle 4 and through the profiled openings 23 it moves axially in the annular gap formed by the cylindrical pipe 12 and the inner pipe 15. At the top of the apparatus, steam (vapor-gas mixture) is discharged through the nozzle 5. Steam (coolant) supplied through the nozzle 6, condensing, is discharged through the nozzle 7.

The use of the invention allows to increase the productivity of the apparatus, reduce capital and current costs, and hence the cost of the product.

Information sources:

1. RU No. 2324516, MKL B01D 1/22, 2007, bull. No. 14, 2008.

2. Voinov N.A., Putintseva N.A., Vyrina E.E. Heat transfer in an air vortex condenser, g. Chemical industry No. 6, t. 90, 2013 with. 291-293 (Fig. 2 and Fig. 4).

3. RU No. 2314139 MKL B01D 1/22; B01D 3/28 2006 g, bull. No. 1, 2008.

Claims (1)

Vortex evaporator-condenser, consisting of a vertical cylindrical body with a cover and a bottom, technological fittings, chambers for entering and leaving coolants, cylindrical pipes equipped with liquid distributors and internal pipes, on the surface of which there are through channels, to the side edges of which profiled plates are tightly connected installed in the guide washers, forming swirls to ensure rotationally translational movement of steam (gas), placed along the height of the cylinder pipes, characterized in that under each swirl there are supporting washers equipped with channels for draining the coolant, the ratio of the inner diameter of the supporting washer d to the inner diameter of the cylindrical pipe D is d / D = 0.6-0.9, and in the guide washers through profiled holes for moving the vapor (gas) in the axial direction, and the ratio of the distance between two adjacent support washers L to the column height of the rotating gas-liquid layer H is equal to L / H ≤ 1, where the value of H is

H is the height of the gas-liquid layer, m,
h is the height of the channels in the swirl, m,

- gas content (gas fraction in the liquid),
D _article - the diameter of the cylindrical pipe, m,
R _zav - swirl radius, m,
u _g - gas velocity in the channels of the swirler, m / s,
m is the mass of rotating water (liquid), kg,
w is the angular velocity of rotation, s ^-1 ,

- respectively, the density of the liquid and gas, kg / m ³ ,

- surface coefficient.

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