CN220443206U - Multistage integral falling film evaporator - Google Patents

Abstract

The utility model discloses a multistage integrated falling film evaporator, which sequentially comprises the following components from top to bottom: the top of the upper evaporator is provided with an upper feed liquid inlet and an upper liquid separation disc, an upper tube plate is arranged below the upper liquid separation disc, and a plurality of upper tube arrays are uniformly distributed in the upper tube plate; the middle expansion cylinder is provided with a conical collection disc at the upper part, the lower port of the conical collection disc is connected with the upper end of the central guide cylinder, the lower end of the central guide cylinder is positioned in the lower liquid separation disc, and a plurality of notches are uniformly distributed on the circumference of the lower end; the upper end of the lower-layer evaporator is provided with a lower-layer upper tube plate, a plurality of lower-layer tube arrays are uniformly distributed in the lower-layer upper tube plate, and the lower end of each lower-layer tube array is embedded in the lower-layer lower tube plate; a lower separating cylinder, the bottom of which is provided with a separating cylinder feed liquid outlet, and the side wall of the upper part of which is connected with a secondary steam communicating pipe; the side wall of the lower part of the flash evaporator is connected with the secondary steam communicating pipe, the top of the flash evaporator is provided with a steam outlet, and the bottom of the flash evaporator is provided with a flash evaporator feed liquid outlet. The evaporator has compact structure, high evaporation efficiency and difficult blockage.

Description

Multistage integral falling film evaporator

Technical Field

The utility model relates to a falling film evaporator, in particular to a multistage integrated falling film evaporator, which belongs to the technical field of evaporation equipment and is used for evaporating and concentrating mixed liquid.

Background

The evaporator is core equipment for evaporating and concentrating mixed liquid, and the reasonable selection of the evaporating device has very important significance for improving the production efficiency of evaporating and concentrating the mixed liquid, reducing the production cost and improving the economic benefit of enterprises. The falling film evaporator is widely applied to the fields of chemical industry, pharmacy, food and the like, and the working principle is that mixed liquid is uniformly distributed on the inner wall of a tube array from the top through a nozzle or a liquid distributor to form a layer of thin liquid film, the components with low boiling point in the liquid film are evaporated under the heating action of a heating medium outside the tube, and the liquid film is continuously formed and flows on the inner wall of the tube from top to bottom under the pushing of gravity and secondary steam, so that the convection heat transfer coefficient is greatly improved, and the evaporation efficiency is greatly enhanced. Compared with a forced film scraping evaporator for treating materials with high concentration, high viscosity and easy coking, the falling film evaporator has the advantages of simple structure, no power consumption, large heat transfer area and large treatment capacity, has high evaporation efficiency, can be widely used in various industries, and has an irreplaceable position in the evaporation and concentration process of some viscous materials.

For example, in the alcohol process for preparing soy protein concentrate, it is necessary to evaporate a dilute syrup having a concentration of 8-35% and comprising, as the main components, soy oligosaccharide, ethanol and water, wherein the oligosaccharide is a highly viscous substance, and the viscosity varies greatly from 10-300 cP during evaporation. The viscosity of syrup with the same concentration is also greatly different at different temperatures, so that the evaporation concentration of the thin syrup is a technical difficulty in the process for preparing the soy protein concentrate by an alcohol method.

The existing falling film evaporator has the defects that the original liquid is unevenly distributed or the liquid is locally overheated in the descending process of the inside of the tube, a continuous liquid film is easily damaged by a large amount of bubbles after the bubbles are broken, the continuous liquid film is broken, the wall is locally dried, coked and gelatinized, even the whole tube is blocked, meanwhile, the partial syrup concentration in the tube is extremely easily formed due to uneven distribution of the liquid in the tube, the coking is serious, the evaporation efficiency and the stable operation of production are influenced, the tube is necessarily stopped and cleaned at intervals of 1-2 months, the production is delayed, the consumption and the safety risk are increased, and the production cost is high. In addition, the subsequent cleaning after the longer tube array is blocked is difficult and incomplete, and the original evaporation effect is difficult to recover.

The Chinese patent with publication number of CN211885427U discloses a tubular falling film evaporator and a tubular falling film evaporation device, and provides a structure that two falling film evaporators are vertically arranged in a staggered mode and are used in series, a liquid distribution device is arranged at the top of a second stage to redistribute liquid material, so that the uniformity of liquid distribution of the whole tube array is ensured, and the length of the tube array after being connected in series is shortened compared with that of the conventional falling film evaporator, so that the tube array is convenient to clean.

The technical scheme has the following defects: the method has the advantages of complex equipment combination, high manufacturing cost, overlarge occupied factory building and high building investment cost.

The secondary steam flow that second level evaporimeter top gas-liquid import pipe department produced can influence the liquid level stability of upper cloth liquid dish, leads to the feed liquid of lower floor aperture to distribute unevenly, has four last pipe boxes that are used for connecting the second level evaporimeter to flash vessel import pipe in the middle of the picture, and the effect is not thin, whether consider the secondary steam that produces the one-level whole or partial short circuit no longer through the shell and tube of second level evaporimeter inside, has the direct relation to the stable and secondary steam flow promotion of thin liquid film of falling film evaporimeter shell and tube inner wall, and is important to high viscosity material, and the promotion of secondary steam flow can slow down the adhesion of feed liquid at the intraductal wall simultaneously.

The temperature of the residual part of the first stage used by the heating steam of the second-stage evaporator is low, so that the exertion of the evaporation efficiency of the second stage is restricted.

Disclosure of Invention

The utility model aims to overcome the problems in the prior art and provide the multistage integrated falling film evaporator which has the advantages of compact structure, high evaporation efficiency, difficult blockage, low equipment cost and convenient maintenance.

In order to solve the technical problems, the multistage integrated falling film evaporator of the utility model sequentially comprises from top to bottom:

the top of the upper evaporator is provided with an upper feed liquid inlet, an upper liquid separating disc is arranged below the upper feed liquid inlet, an upper tube plate is arranged below the upper liquid separating disc, a plurality of upper tube arrays are uniformly distributed in the upper tube plate, and the lower end of each upper tube array is embedded in the upper lower tube plate;

the upper part of the middle expansion cylinder is provided with a conical collection plate for receiving the upper layer tube stock liquid, the lower port of the conical collection plate is connected with the upper end of the central guide cylinder, the lower end of the central guide cylinder is positioned in the lower layer liquid separation plate, and a plurality of notches for outwards distributing liquid are uniformly distributed on the circumference of the lower end of the central guide cylinder;

the upper end of the lower-layer evaporator is provided with a lower-layer upper tube plate for receiving the feed liquid of the lower-layer liquid separation disc, a plurality of lower-layer tubes are uniformly distributed in the lower-layer upper tube plate, and the lower end of each lower-layer tube is embedded in the lower-layer lower tube plate;

a lower separating cylinder for containing the feed liquid and the secondary steam discharged from the lower layer tube array, a separating cylinder feed liquid outlet is arranged at the bottom, and a secondary steam communicating pipe is connected to the side wall of the upper part;

the outlet of the secondary steam communicating pipe is connected with the side wall of the lower part of the flash evaporator, the top of the flash evaporator is provided with a flash evaporator steam outlet, and the bottom of the flash evaporator is provided with a flash evaporator feed liquid outlet.

As an improvement of the utility model, a round upper buffer baffle plate is arranged between the upper part of the center of the upper liquid separating disc and the upper liquid inlet.

As a further improvement of the utility model, the side wall of the cylinder body above the upper tube plate is provided with an upper overflow port, the upper overflow port is connected with an upper overflow pipe, and the lower end of the upper overflow pipe passes through the cylinder wall of the middle expansion cylinder and extends to the upper part of the conical collecting disc.

As a further development of the utility model, the lower cylinder wall of the upper evaporator is connected to the upper cylinder wall of the lower evaporator by a gas phase equalization pipe.

As a further improvement of the utility model, annular channels are arranged between the peripheries of the conical collecting disc and the lower liquid separating disc and the inner wall of the middle expansion cylinder, and a plurality of circumference ventilation holes are uniformly distributed on the circumference of the upper part of the center guide cylinder.

As a further improvement of the utility model, a plurality of steam-passing pipes penetrating through the liquid level are uniformly distributed in the outer ring area of the bottom plate of the lower liquid separation plate.

As a further improvement of the utility model, a middle cylinder overflow port is arranged on the side wall of the cylinder body above the upper tube plate of the lower layer, the middle cylinder overflow port is connected with an overflow pipe of the lower layer, the lower end of the overflow pipe of the lower layer is connected with the side wall of the upper part of the lower separating cylinder, and a lower layer overflow valve is arranged at the upper end of the overflow pipe of the lower layer.

As a further improvement of the utility model, a cleaning spray head is arranged in the middle of the inner cavity of the flash device, and a liquid blocking cover is arranged right below the steam outlet of the flash device.

As a further improvement of the utility model, the bottom center of the flash device is provided with an upward-raised anti-accumulation barrel cover, and the flash device feed liquid outlet is positioned at the junction of the periphery of the anti-accumulation barrel cover and the flash device bottom wall.

As a further improvement of the utility model, the shell side steam inlets of the upper layer evaporator and the lower layer evaporator are respectively arranged at the respective upper amplifying sections, the lower part of the shell side is respectively provided with a condensate outlet, and the lower part of the shell side of the lower layer evaporator is also provided with a lower layer steam outlet.

Compared with the prior art, the utility model has the following beneficial effects: 1. a falling film evaporator is provided with an upper section evaporation unit and a lower section evaporation unit, materials are distributed twice, the structure is compact, the occupied area of a factory building is reduced, the investment is saved, and the equipment cost is reduced.

2. The top liquid distribution space of the second-stage evaporator is enlarged, gas-liquid separation is carried out firstly, feed liquid smoothly enters the liquid distribution disc through the guide cylinder, uniformly falls to Kong Qiaochu of the tube plate by small holes, flows into the inner wall of the tube array, and secondary steam flows to the upper tube plate of the evaporator through the annular channel between the liquid distribution disc and the ventilation pipeline on the liquid distribution disc, so that the liquid level stability of the liquid distribution disc is ensured, the liquid distribution effect is improved, meanwhile, secondary steam of the first stage can be also led into the tube array, the liquid film is pushed to improve the flow speed, the evaporation efficiency is improved, and the adhesion and wall hanging of the feed liquid on the inner wall of the tube are slowed down.

3. The heating heat source used by the shell passes of the two-stage evaporator is secondary steam or raw steam generated by the previous process, and the flow of the steam can be regulated according to the evaporation capacity of each stage by adopting parallel connection; the vapor balance pipe is arranged to keep the balance of the side pressure of the vapor of the two stages of shell side, the design improves the enthalpy value and the temperature of the secondary heating vapor, improves the heat and the heat transfer temperature difference, fully exerts the secondary evaporation efficiency, simultaneously reduces the flow resistance of the vapor of the secondary heat source of the shell side, and improves the production state of poor vacuum degree caused by the pressure holding in the prior process equipment.

4. The material side of the two-stage evaporator is provided with a standby overflow pipe, when one stage of the tubulation is blocked in the emergency in production and the normal flow is influenced, the bypass of the overflow pipe is opened, so that the other stage can be used barely, and the production line loss caused by emergency shutdown is avoided.

5. The evaporator is structurally integrated, internal parts such as an internal liquid distribution disc are assembled in a blocking mode, material residues are few, daily online cleaning and manual shutdown cleaning are achieved, and time, cleaning agent consumption, safety risks and the like are improved.

Drawings

The utility model will now be described in further detail with reference to the drawings and the detailed description, which are provided for reference and illustration only and are not intended to limit the utility model.

FIG. 1 is a front view of a multi-stage integral falling film evaporator of the present utility model;

FIG. 2 is a top view of the upper tube sheet of FIG. 1;

FIG. 3 is an enlarged view of the center guide shell of FIG. 1;

FIG. 4 is a cross-sectional view of the lower tray of FIG. 1;

FIG. 5 is a top view of FIG. 4;

in the figure: 1. an upper layer evaporator; 1a, an upper layer feed liquid inlet; 1b, an upper steam inlet; 1c, an upper condensate outlet; 2. an upper buffer baffle; 3. an upper layer liquid separation disc; 4. an upper tube sheet; 5. an upper layer tube array; 6. an upper overflow pipe; 7. a gas phase balance tube; 8. a middle expansion cylinder; 9. a conical collection tray; 10. a central guide cylinder; 10a, a bottom rectangular notch; 10b, circumference ventilation holes; 11. a lower layer evaporator; 11a. A lower steam inlet; 11b, a lower steam outlet; 11c, a lower condensate outlet; 12. a lower layer liquid separation disc; 13. a steam pipe; 14. a lower upper tube plate; 15. a lower layer tube array; 16. a lower overflow valve; 17. a lower overflow pipe; 18. a lower separation cylinder; 18a, a feed liquid outlet of the separating cylinder; 19. a secondary steam communicating pipe; 20. a flash; 20a, a liquid blocking cover; 20b, a steam outlet of the flash generator; 20c, preventing the cylinder cover from piling up; 20d, a material liquid outlet of the flash generator; and 20e, cleaning the spray head.

Description of the embodiments

In the following description of the present utility model, the terms "upper", "lower", "front", "rear", "left", "right", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are merely for convenience in describing the present utility model and simplifying the description, and do not mean that the device must have a specific orientation.

The utility model is further described with reference to the following detailed drawings in order to make the technical means, the creation characteristics, the achievement of the purpose and the effect of the implementation of the utility model easy to understand.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this utility model belongs. The terminology used herein in the description of the utility model is for the purpose of describing particular embodiments only and is not intended to be limiting of the utility model.

As shown in fig. 1, the multistage integral falling film evaporator of the utility model comprises an upper layer evaporator 1, a middle expansion cylinder 8, a lower layer evaporator 11, a lower separation cylinder 18 and a flash evaporator 20, wherein the upper layer evaporator 1 is arranged at the uppermost part, an upper layer feed liquid inlet 1a is arranged at the top of the upper layer evaporator, a round upper buffer baffle plate 2 is arranged below the upper layer feed liquid inlet 1a, molasses or other materials fall on the upper buffer baffle plate 2 to be buffered after entering from the upper layer feed liquid inlet 1a, and fall from the periphery of the upper buffer baffle plate 2. An upper liquid separating disc 3 is arranged below the upper buffer baffle 2, and the periphery of the upper liquid separating disc 3 is upwards erected to keep a certain liquid level in the disc. A plurality of small liquid distribution holes are uniformly and densely distributed on the bottom plate of the upper liquid separation plate 3, and an upper tube plate 4 is arranged below the upper liquid separation plate 3.

As shown in fig. 2, a plurality of upper layer tubes 5 are uniformly distributed in the upper layer tube plate 4, and projections of liquid distribution holes of the upper layer liquid separation disc 3 are symmetrically distributed on the periphery of an upper port of each upper layer tube 5 in a regular triangle shape, so that uniform liquid distribution to each upper layer tube 5 is ensured, and uniform film hanging on the inner wall of the upper layer tube 5 is ensured.

The lower cylinder of the upper tube plate 4 is provided with an upper amplifying section, the cylinder wall of the upper amplifying section is provided with an upper steam inlet 1b, and steam can quickly enter the cross section of the whole shell pass along the circumference of the upper amplifying section after entering. The lower part of the shell side of the upper evaporator 1 is provided with an upper condensate outlet 1c.

The middle expansion cylinder 8 is connected below the upper layer evaporator 1, and the diameter of the cylinder body is larger than that of the upper layer evaporator 1. The lower ends of the upper layer tubes 5 are embedded in the upper layer lower tube plate, and a conical collecting disc 9 is arranged at the upper part of the upper layer evaporator 1 so as to receive the feed liquid flowing out of the upper layer tubes 5.

The wall of the cylinder below the upper lower tube plate can also be provided with a guide ring for guiding the peripheral material into the conical collecting tray 9. The lower port of the conical collection disk 9 is connected with the upper end of the central guide cylinder 10, and the lower end of the central guide cylinder 10 is positioned in the lower liquid separation disk 12.

Annular channels are arranged between the peripheries of the conical collecting disc 9 and the lower liquid separating disc 12 and the inner wall of the middle expansion cylinder 8, and secondary steam generated by evaporation of the upper evaporator 1 flows downwards.

As shown in fig. 3, a plurality of bottom rectangular notches 10a are uniformly distributed on the circumference of the lower end of the central guide cylinder 10, and the feed liquid entering the central guide cylinder 10 flows out from each bottom rectangular notch 10a, uniformly enters the lower liquid separation disc 12, flows out from each liquid distribution hole of the lower liquid separation disc 12, and distributes liquid to the lower layer. A plurality of circumference ventilation holes 10b are uniformly distributed on the circumference of the upper part of the center guide cylinder 10, so that the exhaust is convenient, and the feed liquid smoothly flows downwards.

As shown in fig. 4 and 5, a plurality of steam-passing pipes 13 penetrating through the liquid level are uniformly distributed in the outer ring area of the bottom plate of the lower liquid separation disc 12, so as to increase the flow area of the secondary steam and reduce the flow resistance of the secondary steam.

The lower evaporator 11 is connected below the middle expansion cylinder 8, the upper end of the lower evaporator 11 is provided with a lower upper tube plate 14, and the feed liquid flowing out from the lower liquid separation disc 12 is uniformly distributed on the lower upper tube plate 14. A plurality of lower-layer tubulars 15 are uniformly distributed in the lower-layer upper tube plate 14, and the lower ends of the lower-layer tubulars 15 are embedded in the lower-layer lower tube plate. The secondary steam generated by the primary evaporation flows downward along the center of each lower-layer column 15.

The projections of the liquid distribution small holes of the lower liquid distribution disc 12 are symmetrically distributed on the periphery of the upper port of each lower tube 15 in a regular triangle, so that the uniform liquid distribution to each lower tube 15 is ensured, and the uniform film hanging on the inner wall of the lower tube 15 is ensured.

The lower cylinder of the lower upper tube plate 14 is provided with a lower amplifying section, a lower steam inlet 11a is arranged below the cylinder wall of the lower amplifying section, and steam can quickly enter the cross section of the whole shell pass along the circumference of the lower amplifying section after entering. The lower shell side of the lower evaporator 11 is provided with a lower condensate outlet 11c and a lower vapor outlet 11b. The lower cylinder wall of the upper layer evaporator 1 is connected with the upper cylinder wall of the lower layer evaporator 11 or connected with the lower steam inlet 11a through the gas phase balance pipe 7, so that the pressure balance of the upper evaporator and the lower evaporator shell pass is kept.

The lower separation tube 18 is connected below the cylinder of the lower evaporator 11, and the feed liquid and the secondary steam discharged from the lower tube 15 enter the lower separation tube 18. The bottom center of the lower separating tube 18 is provided with a separating tube feed liquid outlet 18a, and the upper side wall of the lower separating tube 18 is connected with a flash evaporator 20 through a secondary vapor communicating tube 19.

The top of the flash device 20 is provided with a flash device steam outlet 20b, and a liquid blocking cover 20a is arranged right below the flash device steam outlet 20b. The bottom of the flash evaporator 20 is provided with a flash evaporator feed liquid outlet 20d for the flashed feed liquid to flow out.

The bottom center of the flash evaporator 20 is provided with an upward-raised anti-accumulation barrel cover 20c, and a flash evaporator feed liquid outlet 20d is positioned at the junction of the periphery of the anti-accumulation barrel cover 20c and the bottom wall of the flash evaporator, so that feed liquid residues are avoided.

The cleaning spray head 20e is arranged in the middle of the inner cavity of the flash evaporator 20, so that the inner wall of the flash evaporator 20 is conveniently cleaned by the production gap.

During operation, molasses or other feed liquid enters from an upper feed liquid inlet 1a at the top of the upper evaporator 1, and flows into an upper liquid separation disc 3 after being dispersed and slowed down by an upper buffer baffle plate 2, a certain liquid level is stably stored in the upper liquid separation disc 3, and the feed liquid falls to a hole bridge of an upper tube plate 4 at the bottom of the liquid separation disc, flows into the inner wall of an upper tube nest 5 and is in a complete infiltration state, so that initial liquid distribution of molasses is completed. In the process of the downward flow of the liquid film in the pipe, the liquid film is heated by the heating steam outside the pipe to generate secondary steam to push the liquid film to flow downwards rapidly, and the thickness of the liquid film is greatly reduced, so that the convection heat transfer coefficient is greatly improved, and the coking formation is slowed down.

The feed liquid evaporated from the upper layer and the secondary steam evaporated from the first stage flow out from the lower port of the upper layer tube array 5 together and enter the middle expansion cylinder 8 to complete the primary vapor-liquid separation, so that the separation of the feed liquid and the secondary steam flow paths is not interfered with each other.

The primary feed liquid falls into the conical collecting disc 9 to be collected, then enters the central guide cylinder 10, flows out of each bottom rectangular notch on the circumference of the lower end of the central guide cylinder 10, is uniformly distributed and dispersed in the lower-layer liquid separating disc 12, and falls onto the lower-layer upper tube plate 14 through the small holes of the lower-layer liquid separating disc 12, so that the feed liquid is distributed on the inner wall of the lower-layer tube 15.

The lower liquid distribution plate is of a block structure, can be detached and is convenient to clean, and a certain number of steam-passing pipes 13 are arranged on the periphery of the liquid distribution plate, and the ports of the steam-passing pipes 13 are just corresponding to the heat exchange pipes below the steam-passing pipes. Part of the secondary steam flows downwards through an annular channel between the lower liquid distribution disc and the inner wall of the middle expansion cylinder 8; the other part is guided to the position of the lower upper tube plate 14 through the steam-passing tube 13 on the lower liquid distribution disc and then is introduced into the lower tube 15, so that the downward flow speed of the liquid film is pushed, and the second-stage evaporation of the liquid in the lower tube 15 is completed quickly.

The feed liquid and the secondary steam after the secondary evaporation enter the lower separating cylinder 18 from the lower port of the lower layer tube array 15, and after the primary vapor-liquid separation is finished, the secondary steam with a small amount of liquid drops is led out by the secondary steam communicating pipe 19 and further screwed into the flash evaporator 20 along the tangent line for further vapor-liquid separation.

In the flash evaporator 20, after the liquid blocking cover 20a at the top of the flash evaporator 20 is hit in the rising process of the secondary steam for safe drip removal, the secondary steam is discharged from the steam outlet 20b of the flash evaporator at the top and enters the next working section. The liquid flows out from the liquid outlet 20d of the flash vessel under the action of gravity, and the liquid discharged from the liquid outlet 18a of the separating tube is converged and pumped by the circulating pump,

and after the extraction, part of feed liquid returns to the feed liquid inlet 1a of the upper layer for circulation, and the other part of feed liquid enters the equipment of the lower channel working section. For falling film evaporators, especially for treating viscous and easy-to-scale materials, proper self-circulation amount is an important means for ensuring the minimum wetting rate of the inner wall of the evaporator tube array, preventing dry wall, adhesion and wall hanging.

The upper and lower two-stage evaporators are externally provided with standby overflow pipes, the diameter of the lower overflow pipe 17 is larger, the feed liquid can not overflow to the height of the overflow port under normal conditions, the feed liquid is evaporated in the upper and lower two stages, and the lower overflow valve 16 is closed.

The side wall of the cylinder body above the upper tube plate 4 is provided with an upper overflow port, the upper overflow port is connected with an upper overflow tube 6, and the lower end of the upper overflow tube 6 passes through the cylinder wall of the middle expansion cylinder 8 and extends to the upper part of the conical collecting disc 9.

When the upper layer tube array 5 in the upper layer evaporator 1 is blocked, the feed liquid flows into the conical collecting tray 9 in the middle expansion cylinder 8 directly by the upper layer overflow tube 6 when the feed liquid slowly rises above the upper layer tube plate 4 to reach the height of the overflow port, and then the liquid distribution on the inner wall of the lower layer tube array 15 is completed in the manner described above, and at the moment, the lower layer overflow valve 16 is closed.

The side wall of the cylinder body above the lower layer upper tube plate 14 is provided with a middle cylinder overflow port, the middle cylinder overflow port is connected with a lower layer overflow pipe 17, the lower end of the lower layer overflow pipe 17 is connected with the upper side wall of a lower separation cylinder 18, and the upper end of the lower layer overflow pipe 17 is provided with a lower layer overflow valve 16.

When the lower layer tube array 15 in the lower layer evaporator 11 is blocked, after the feed liquid is evaporated by the upper layer evaporator 1, the secondary steam and the feed liquid are directly led into the lower separating cylinder 18 through the lower layer overflow pipe 17, and the lower layer overflow valve 16 is opened. The diameter of the lower overflow pipe 17 is large because a large amount of secondary steam needs to be passed.

The heating heat source of the two-stage evaporator shell passes is secondary steam or raw steam in the previous process, steam is supplied to the two-stage shell passes in a parallel mode, and the flow of the steam can be regulated according to the respective evaporation capacity.

The gas phase balance pipe 7 keeps the balance of the side pressure of the two-stage shell side steam, the design improves the enthalpy value and the temperature of the two-stage heating steam, the heat and the heat transfer temperature difference are improved, the secondary evaporation efficiency is fully exerted, the flow resistance of the shell side secondary heat source gas phase is reduced, and the production state of poor holding vacuum degree in the prior process equipment is improved.

The foregoing description of the preferred embodiments of the present utility model illustrates and describes the basic principles, main features and advantages of the present utility model, and is not intended to limit the scope of the present utility model, as it should be understood by those skilled in the art that the present utility model is not limited to the above-described embodiments. In addition to the embodiments described above, other embodiments of the utility model are possible without departing from the spirit and scope of the utility model. The utility model also has various changes and improvements, and all technical schemes formed by adopting equivalent substitution or equivalent transformation fall within the protection scope of the utility model. The scope of the utility model is defined by the appended claims and equivalents thereof. The technical features of the present utility model that are not described may be implemented by or using the prior art, and are not described herein.

Claims (10)

1. A multistage integral type falling film evaporator, characterized by comprising from top to bottom in proper order:

the top of the upper evaporator is provided with an upper feed liquid inlet, an upper liquid separating disc is arranged below the upper feed liquid inlet, an upper tube plate is arranged below the upper liquid separating disc, a plurality of upper tube arrays are uniformly distributed in the upper tube plate, and the lower end of each upper tube array is embedded in the upper lower tube plate;

the upper part of the middle expansion cylinder is provided with a conical collection plate for receiving the upper layer tube stock liquid, the lower port of the conical collection plate is connected with the upper end of the central guide cylinder, the lower end of the central guide cylinder is positioned in the lower layer liquid separation plate, and a plurality of notches for outwards distributing liquid are uniformly distributed on the circumference of the lower end of the central guide cylinder;

the upper end of the lower-layer evaporator is provided with a lower-layer upper tube plate for receiving the feed liquid of the lower-layer liquid separation disc, a plurality of lower-layer tubes are uniformly distributed in the lower-layer upper tube plate, and the lower end of each lower-layer tube is embedded in the lower-layer lower tube plate;

a lower separating cylinder for containing the feed liquid and the secondary steam discharged from the lower layer tube array, a separating cylinder feed liquid outlet is arranged at the bottom, and a secondary steam communicating pipe is connected to the side wall of the upper part;

the outlet of the secondary steam communicating pipe is connected with the side wall of the lower part of the flash evaporator, the top of the flash evaporator is provided with a flash evaporator steam outlet, and the bottom of the flash evaporator is provided with a flash evaporator feed liquid outlet.

2. The multi-stage integrated falling film evaporator according to claim 1, wherein: a round upper buffer baffle plate is arranged between the upper part of the center of the upper liquid separating disc and the upper liquid inlet.

3. The multi-stage integral falling film evaporator according to claim 2, wherein: the upper overflow port is connected with the upper overflow pipe, and the lower end of the upper overflow pipe penetrates through the wall of the middle expansion cylinder and extends to the upper part of the conical collecting disc.

4. The multi-stage integrated falling film evaporator according to claim 1, wherein: the lower cylinder wall of the upper layer evaporator is connected with the upper cylinder wall of the lower layer evaporator through a gas phase balance pipe.

5. The multi-stage integrated falling film evaporator according to claim 1, wherein: an annular channel is arranged between the peripheries of the conical collecting disc and the lower liquid separating disc and the inner wall of the middle expansion cylinder, and a plurality of circumferential ventilation holes are uniformly distributed on the circumference of the upper part of the center guide cylinder.

6. The multi-stage integrated falling film evaporator according to claim 1, wherein: a plurality of steam-passing pipes penetrating through the liquid level are uniformly distributed in the outer ring area of the bottom plate of the lower liquid separation plate.

7. The multi-stage integrated falling film evaporator according to claim 1, wherein: the upper tube plate is characterized in that a middle tube overflow port is arranged on the side wall of the tube body above the upper tube plate of the lower layer, the middle tube overflow port is connected with the overflow tube of the lower layer, the lower end of the overflow tube of the lower layer is connected with the side wall of the upper part of the lower separating tube, and a lower overflow valve is arranged at the upper end of the overflow tube of the lower layer.

8. The multi-stage integrated falling film evaporator according to claim 1, wherein: the middle part of the inner cavity of the flash device is provided with a cleaning spray head, and a liquid blocking cover is arranged right below the steam outlet of the flash device.

9. The multi-stage integrated falling film evaporator according to claim 1, wherein: the bottom center of the flash device is provided with an upward-raised anti-accumulation barrel cover, and the flash device feed liquid outlet is positioned at the junction of the periphery of the anti-accumulation barrel cover and the bottom wall of the flash device.

10. The multi-stage integrated falling film evaporator according to any one of claims 1 to 9, wherein: the shell side steam inlets of the upper layer evaporator and the lower layer evaporator are respectively arranged at the respective upper amplifying sections, the lower part of the shell side is respectively provided with a condensate outlet, and the lower part of the shell side of the lower layer evaporator is also provided with a lower layer steam outlet.