HU194062B - Supermultiflash type evaporation device - Google Patents

Abstract

In the evaporator space the soln. which is to be concentrated is boiling continuously while having a free surface and forced circulation. Pressure redn. is provided only by the friction against the walls of the evaporator space. The temp. change along the stream is therefore continuous, providing the equivalent of an infinite number of evaporator stages. In the condenser space the condensate is cooled against the incoming soln. in a similar manner. A third space is provided for de-gassing. This is in a spiral form, wound together with the others. In the de-gasser space boiling releases gases which are partially condensed in a condenser channel by cooling against the incoming soln. Non-condensible gases are removed by vacuum pump or other means.

Description

FIELD OF THE INVENTION The present invention relates to a multiflash evaporator having a continuous evaporation chamber, a vaporizing apparatus having a continuous evaporation chamber, a vaporization solution having a continuous open source in a stream of liquid, there is no singularization of its vapor tensile or boiling point function, so the number of degrees can be considered infinite. Due to the simple design of the evapotranspiration space, which also has an infinite number of chokes, the multiflash device of the present invention is universally applicable to all flow-forced solutions, liquids, while optimally utilizing the full temperature range available.

For the separation of solutions for which the tensile solubility of the solute is negligible one of the world-wide methods is evaporation, or as domestic literature calls it concentration. This chemical operation is usually carried out in an apparatus consisting of a heat exchanger and a droplet separator. It has long been known to connect these devices in series, either directly or countercurrent, so that a rough approximation of one kilogram of heating steam can yield a distillate (solvent) of the same mass as the solvent, if the solvent is water. However, the number of bodies is not usually set to more than six, because in this case the operation of the plant, although improving in terms of energy demand, is extremely difficult in terms of control technology. Therefore, these bodies are placed inside a device (steps, in which case the operation of the device will be easier, but its dimensioning, precise thermo-technical, flow-technical and constructional design require a high level of theoretical knowledge and long experimental work. (Multilayer evaporators have only recently been used, primarily in their simpler embodiment, where the solution brought to the boiling point is suppressed in a large space where droplet separation is safely solved and foaming does not cause such a problem that the distillate solution is contaminated. The large space also contributes to the safer operation of the device from a regulatory technology point of view. The domestic industry also manufactures a slightly more sophisticated form of this multiflash device, where instead of suppressing it into a relatively large space, k flows in a short, continuously expanding closed conduit and, in the closed conduit, the vapors that excel due to the throttle are separated by the centrifugal force from the liquid or droplets containing the solute, the vapors flow into the condenser while the liquid goes to the next stage for the next expanding closed channel, (see Hungarian Patent Nos. 153,968 and 156,428, respectively). However, this method makes it difficult to make up the large space inside a device, since the source and separation created by the pressure drop in a continuously expanding closed channel must be played simultaneously. Of course, this requires the creation of a closed channel with variable geometry. The source and separation of the two processes is difficult to provide at the same time, since the channel length is limited due to the small size. Therefore, it is advisable to even design a separate droplet separator to ensure safe droplet separation. To overcome this dual process, the inventors have applied a so-called flashlng device in the patent application EE-2624 OTH, which actually complicates the construction, all the more since they also need to be changed step by step. Therefore, effective separation without increasing the size of the apparatus can be achieved by this method only by using a sophisticated design of a throttle that is individually sized and experimentally measured with high precision. A major disadvantage of these choke assemblies is that the vapors released during the choke - precisely because of the choke - lose their useful temperature difference in the heat exchange in the condenser cooled by the warming solution. Taking into account that the temperature drop on the throttle is 3.5 K ° / degree on average, the normal heat transfer temperature difference is 6 K °, so that due to the temperature on the throttle, approx. just the heat exchanger surface. Due to the above, this method has practically survived in seawater desalination plants, but it has not been universally prevalent despite its proven efficiency even in its present state (see Gmelin, Water Desalting Suppl. Vol. 96.p.)

The object of the present invention is to introduce innovations in the device of the above principle, in which the throttle element is simple, so that it can be generally applied to any flowable liquid, solution; moreover, this new series of chokes should enable the device to operate without loss of temperature due to the choke, so that it is optimally thermodynamically designed. This dual object is achieved by providing a forced circulation continuous open-surface source stream, the ordered hydrodynamic flow form of the known ring-dominated force, the solvent vapor which evaporates over a relatively large surface area. is conducted perpendicular to the flow direction into the condenser, where it is condensed in the known manner by cooling the warming solution. The open-surface source flow is choked by saturated liquid by contacting, frictional contacting the wall of the evaporation space, or the surface of the solid inserted therein, and the frictional work being covered by the differential pressure. Given that the flow pressure gradient is approximately constant throughout, that is, the flow pressure function has no singularity, so that the flow velocity is also approximately constant. All these in the flow temperature function mean that there is no jump in it, the temperature is constantly decreasing, which corresponds to an infinite number of step elements, throttling, that is, the total temperature drop acts as a driving force for heat exchange in the condenser. The advantages of the wall effect created by the forces acting on the biphasic flow are exploited and made safer for the operation of the device by, on the one hand, winding up the evaporation space in the form of a sprayer and, on the other hand, It is to be emphasized that with the selected flow form, continuous surface evaporation is not achieved with a bubble source. According to the fluid conduction of the multiflash thickeners, the warming solution is conducted parallel to the evaporation space in a closed space, but its flow direction is opposite to that of the evaporating liquid, it is heated by solution, but separately in a channel open to the steaming space. Flowing open-surface evaporative solution, together with solvent vapors, also releases gases due to the throttle, for which we have proposed two solutions: venting gases to the highest solution temperature without using a vacuum pump, ie without external energy supply, or venting to the lowest vacuum . In both cases, a separate closed channel solution cooling is provided in the venting space to facilitate partial vapor condensation.

The invention will now be described with reference to the accompanying drawings, in which:

Fig. 1 is a radial sectional view of a spirally wound device of nested closed profiles.

Figure 2 is a radial sectional view of a device consisting of a closed extruded profile spirally wound in a closed space, including venting spaces; so this is the most typical figure.

Figure 3 shows a radial sectional view of a welded design with at least two spheres.

Figure 4 shows a preferred embodiment of the venting channel of the extruded profile of Figure 2.

Figure 5 shows a preferred embodiment of the ceiling shutter plate of the extruded profile of Figure 2.

Fig. 6 shows elements of a boiler space of at least a two-space profile formed by wires inserted in a preferred embodiment.

Figure 7 is a circuit diagram for fluid delivery.

In the embodiment shown in Fig. 1, a boiling profile 40 including the boiling space 1 and the condenser space 2 is drawn in parallel to the outer profile 25. The boiling space 1 is also separated from the warming solution 18 by the thermal insulation 13. In the boiling space 1, the evaporating solution is located in relation to the solution surface 12. The kettle space 1 is bounded from above by a vent 27, which has holes 28 therein. The hover channel 27 has a collision deflector 29. The air that accumulates in the venting space 3 can be led out of the venting profile 40 at the venting outlet 19 by providing a recess 26 on the outer profile 25. Any condensed vapors from the venting channel 27 may be led through condensate tube 30 to condenser space 2. The position of the venting channel 27 is provided by the ribs 31. Due to the relatively small dimensions, the condensation space 2 has very good heat transfer coefficients, so that the heat transfer ribs 21 increase the outer surface and bring the same external-internal heat transfer coefficients. Of course, due to the spiral winding, the vapors condensing in the condenser space 2 are located in accordance with the surface of the distillate 11. The kettle profile 40 is divided by the response plate 5 into the kettle space 1 and the condenser space 2. In the embodiment shown in the figure, the response plate 5 is double. On the one hand, this increases the surface of the condenser, and on the other hand, the size of the steam passage 33 can be well adjusted during manufacture. This change is required primarily at the material inlet, where it is desirable to reduce this vapor transfer size to zero for the length required by the turbulent, stable formation of solution color 12. Of course, in the double embodiment of the response plate 5, increasing the distance of the two plates from one another can reduce the potential drip application to the capacitor space. It is also advantageous to discontinue the steam passage 33 where the response plate 32 is located for venting, so that the upstream vent 19 may be enriched with upwardly flowing inert gas. Further, the size of the steam passage 33 substantially influences the tangential component of the superficial vapor flow of the flowing liquid; Therefore, it is expedient to increase it as the volume of steam increases with increasing pressure.

As shown in Fig. 2, the kettle profile 40 has three spaces: a kettle space 1, a condenser space 2 and a vent space 3. Unlike the previous figure, this boiling profile 40 is wound into the space of the warming solution 18 enclosed by the cylindrical shells 9 and 14. The kettle space 1 is separated by the heat-insulating layer 13 from the heating solution flowing upwardly. The response plate 5 is enlarged by the flange 23, allowing safer guidance of the distillate. Another advantageous embodiment is that the venting can be effected efficiently with minimal vapor loss by allowing the non-condensing gases in the condenser space 2 to pass through the vapor passage 8 into the venting space 3 without the tangential velocity component. The vertical venting space is partitioned by the response plates 32 and, contrary to the flow direction of the boiling space 1 and the condenser space 2, the injected gases may leave the boiling profile 40 via the venting outlet 19. The condensation channel of the vent 4 is relatively large and therefore has a low flow rate. Thus, the pressure drop according to the height of the entire device does not occur here. Therefore, a fixed throttle 20 is disposed in the vent 19. Since the inert gases discharged from the fixed throttle element 20 also contain solvent vapors, the solution conduit 17 provides satisfactory partial condensation in the duct condenser channel. In this channel, the condensed vapors flow downward as a result of the spiral winding, while the continuously inert gas enriches the medium upwards. It is understood that, in such an embodiment, the condensation channel 4 of the venting enclosed between the cylindrical shells 9 and 10 is sealed by thermal insulations 15 and 16 from the adjacent solution-cooled space (s). In less demanding embodiments, these thermal insulations 15 and 16 may be omitted, whereupon the solution conduit 17 is replaced by a baffle. A vent 22 is provided in the vent space 3 to reduce vent vent 19. This deaeration week should ensure the upward flow of inert gas and the removal of condensation there. This is achieved by the holes 28. The only source of significant reduction in caloric efficiency in the evaporator of the present invention is venting. Therefore, in a preferred embodiment, inert gases spirally upwardly directed in the duct condenser channel must be collected in the upper part of the device and preferably passed through a closed conduit, but also in the duct condenser channel 4 to the bottom of the device. At the upper air vent outlet, if the device is well dimensioned for the conditions, vacuum-31

194,062 pumps are not required to remove Inert gases, even with a high end vacuum device. Lower venting requires the latter. It is understood that in the case of helical coils which are nested - in the absence of the outer profile 25 but of the heating solution 18 bounded by at least the cylindrical sheaths 9 and 14, in the preferred embodiment the inner coil make up his cloak. Another advantageous embodiment of the condensation channel of the venting condenser 4 may be the use of the solution line 17 for venting, the venting outlet 19 of which is led through the fixed throttle member 20 to the outer space of the tube. The venting pad 22 may also be made in its material in the case of an extruded boiler profile 40 as shown in Figure 4, whereby the inert gas-enriched medium enters the upper space of the venting space after collisional separation / throttling. Even in the extruded embodiment of the boiler profile 40, there is a further opportunity to improve the internal condensation heat transfer coefficient. In particular, the material of the ceiling panel 24 is formed into a material 41 arched material. This is shown in Figure 5. The curved arches 41 terminate in the drop collectors 43, thus providing a good approximation of · condensation depending on the slope of the spiral. At the solution walls 34, the length of the condensation film can be reduced by the use of drip removers 45, so that droplets 42 collect rapidly and leave the heat exchange wall.

Figure 3 shows a welded embodiment of the boiler profile 40, wherein the response plate 5 is welded to the cold / hot bent closed profile and thereby partially closes it. In accordance with the wide range of applications, the inserts 44 are provided in the boiler space as shown in FIG. 6 and are primarily intended to increase the frictional resistance. These rod-wire projections are either stochastically drawn; in this case, it must be ensured that they cannot restrict the steam passage 33. This can be achieved by locating in bulk or by angular V-bending. · In the case of non-stochastic inserts 44, they are fastened relative to one another by spacers and then retracted into the boiling space 1. In the case of an extruded boiler profile, the frictional resistance can be increased by the length / tangential grooves made in the material. Due to the variable structural material, the arrangement, and the chosen geometry, variable capacitor surfaces can be assigned to a unit length of boiler. Accordingly, in order to intensify the apparatus or achieve more efficient droplet separation, the inserts of Figure 6 may be formed by combing cylindrical sheaths in a preferred embodiment in which radial holes are provided for outward flow of fluid by centrifugal force or flow into a steam condenser space. As a result, the liquid flows through thin vertical slots, which increases its pressure gradient, while at the same time pushing the comb-like elements into the condenser space through a collision droplet separator. In another preferred embodiment, the solution is provided by passing the heated solution line in the condenser space. As a result, the thermal insulation required to maintain the evaporative ability of the boiling liquid in the case of external warming solution conducting the two types of temperature fields is lost. It is to be emphasized that the apparatus according to the invention operates in the annular flow region of the biphasic flow. By passing liquid and gas through a closed profile (regardless of direction - water filtration / vertical), a velocity is achieved where the liquid is located farthest from the center of the gas core. (For example, in the corners of a rectangular section) Thus, when passing saturated liquid brought to a boiling point through a horizontal, rectangular closed section, a condenser tube parallel to the closed section is placed in the vapor space, acting as a distillate It works as a super multifiash device, because its friction causes the tension to decrease continuously, and thus the evaporation temperature. Obviously, by increasing the section sizes and decreasing the specific mass flows, the efficiency of droplet separation can be increased, i.e. the contamination of the distillate with the solution can be reduced. However, this simplified principle would require an extremely long pipeline or device size, since the available pressure drop is only used to overcome friction. Therefore, preferred embodiments are spirally wound the infinitely parallel parallel spaces, channels. Of course, the apparatus can be constructed not only from vertical spirals, it can also be made horizontal or conical spirals and superimposed by vertical fluid passages, and the condenser space 2 can be placed above the kettle space, including the distillate space running parallel to the kettle space. with capacitor space.

Figure 7 is a simplified circuit diagram of an evaporator according to the invention. The boiling profile 40 passes through the boiling solution line 103 and the distillate line 104. They form a common space and travel in one direction, due to differential pressure and gravitational forces down the winding line. The solution flowing through the heating solution line 101 cools and condenses the vapors leaving the boiling solution as described above. The warming solution runs countercurrent with the continuously boiling and thus thickening solution and the distillate is today. It is shown that from the boiler profile 40 through the venting outlet 19 the boiler profile 40 leaves the injected gases through the fixed throttle 20. Between the cylindrical shells 9 and 10, the vapor-enriched vapors in the vent gas condenser channel 4 are further enriched by a cooler solution flowing upwardly in the branching of the warming solution 102 and continuously cooling down the distillate reservoir to form a condensate stream 106. The distillate that accumulates in the boiling profile is also entered here. Because of the openness of the solution reservoir 120 to be concentrated, the final condensation pressure of the system is below atmospheric and therefore the distillate 125 must be extracted from the distillate reservoir by the distillation pump 124 via line 108. The condensed solution leaves the boiler profile via line 107 and is transported by pump 123 to atmospheric storage 122. In the deaeration condenser conduit 4, the vapor is separated from the injected gases and exits the apparatus via the inert gas conduit 109 according to the al-5 gas flow. The heated solution on the heated solution line 101 is combined with the vent portion of the heated solution line 102 to 4194.062, fed to the heat exchanger 126, where heat is applied, and the entire amount of heated solution is returned to the boiling profile 40. Although the system leaves the gases through the inert gas line 109 at the maximum temperature of the end temperature, it is always a question of economics whether the gas thus discharged would retain the energy needed to operate the decisive pump or the vacuum pump.

Advantages of the invention include:

- infinite number of steps due to infinitely small differential pressure drop and the resulting high heat exchange surface savings;

- high heat transfer factors due to contraction;

- an air vent approach approaching the ideal;

- its suitability for thickening all pumpable liquids due to the simple throttle element;

- buildability from any structural material (steel, titanium, glass, plastics)

- easy, reliable modeling both mathematically and experimentally;

- buildability from the smallest unit with a heat transfer surface of 1-2 m'to plants with heat transfer surface area of several thousand square meters;

- small space requirement.

Claims (7)

A supermultiflash evaporator which has a counterflow heat exchanger for exchanging heat between the solution to be heated and the evaporator, one side of which is formed by a kettle space, characterized in that the kettle space (1) is formed as a longitudinal space parallel to the heat exchanger. (18) furthermore, there is a continuous or intermittent steam transfer (33) between the longitudinal condenser space (2) parallel to the boiler space (1), which also forms one side of the heat exchanger. Evaporation device according to Claim 1, characterized in that the boiler space (1) and the condenser (2) are arranged parallel to each other, helically or in a coil line. Evaporator device according to claim 1 or 2, characterized in that the ld10 yarn space (1) and / or the condenser space (2) have venting outlets (19) and the device has a boiling space (1), a condenser space (2), possibly a vent space (3) formed adjacent to the solution (18). 4. A venting device according to any one of the preceding claims, characterized in that a condenser channel (4) is connected to the vent space (3) or the vent terminals (19), which contains solution lines (17) forming an additional heat exchanger. The steam evaporator according to claim 4, characterized in that an inert gas conduit (109) is connected to the condenser ducts (4). 6. Evaporator according to any one of claims 1 to 4, characterized in that 25 that · there are weeks (44) to increase the flow resistance in the boiler room. The vaporizer device according to claim 1, characterized in that the solution space (18) is arranged in the condenser space (2) and / or in the boiler space (1). 30 8. Figures 1-7. A vaporization device according to any one of claims 1 to 3, characterized in that the solution space (18) has a rib (21) and the condenser space (2) has a drop collector (43) and / or a drop remover (45).