Intelligent liquid distribution equipment for falling-film evaporator and use method of intelligent liquid distribution equipment

Abstract

The invention discloses intelligent liquid distribution equipment for a falling film evaporator and a use method of the intelligent liquid distribution equipment. The intelligent liquid distribution equipment comprises a shell as well as a feeding pipe, a primary liquid distribution unit, a pressurizing unit, an intelligent liquid distribution and distribution unit, a tube nest and a discharging pipe which are sequentially arranged in the shell from top to bottom, the feeding pipe is connected with the primary liquid distribution unit, the primary liquid distribution unit is connected with the pressurizing unit, the pressurizing unit is connected with the intelligent liquid distribution and distribution unit, the intelligent liquid distribution and distribution unit distributes liquid to the tube nest, and the tube nest is connected with the discharging pipe. By utilizing the liquid distributor, the film can be uniformly distributed no matter whether the liquid from the liquid distributor is stable or not, then the liquid distribution flow can be intelligently adjusted, steam can be effectively utilized for preheating, and meanwhile, non-uniform film distribution caused by steam influence is avoided.

Description

Technical Field

[0001] The invention relates to the field of falling film evaporators, and in particular to an intelligent liquid distribution device for a falling film evaporator and a use method thereof. Background Art

[0002] Among thin film evaporators, falling film evaporator is famous for its excellent evaporation efficiency. It, together with the other two thin film evaporators (rising film evaporator and wiped film evaporator), constitutes the three major categories of thin film evaporators. In particular, vertical falling film evaporator is one of the falling film evaporators. It is widely used in many industrial fields, including chemical industry, light industry, synthetic fiber, food processing, pharmaceutical, seawater desalination, wastewater treatment and metal smelting, for its excellent performance characteristics, such as high heat transfer efficiency, rapid heating of materials, gentle treatment of sensitive materials to prevent decomposition, low pressure loss, heat loss caused by small temperature difference, significant energy saving effect, strong anti-scaling ability and low internal liquid retention.

[0003] For example, a Chinese patent document with publication number CN114191830A discloses a vertical external tube falling film evaporator, which includes an outer shell; a material inlet channel is penetrated through the top of the outer shell; a material outlet channel is arranged at the bottom of the outer shell; a distribution plate and a falling film evaporation unit are arranged in sequence inside the outer shell along the material inlet channel in a downward direction; the falling film evaporation unit includes a first tube sheet, a second tube sheet and at least one single-head heat exchange tube.

[0004] The Chinese patent document with publication number CN105890238A discloses a vertical falling film evaporator with a novel liquid separation device, including an evaporator upper end, an evaporator main body and an evaporator lower end. The evaporator upper end is for water circulation; the evaporator main body includes a refrigerant liquid inlet flute arranged in parallel in layers, a novel liquid distribution tray, etc., a suitable refrigerant distributor is arranged inside the main body, the refrigerant can be evenly distributed to the surface of the tube bundle, and fully contact with the surface of the tube bundle, and a refrigerant sedimentation liquid return device is arranged at the bottom of the main body; the evaporator lower end is used for water circulation and discharge of sediment.

[0005] The main function of the vertical falling film evaporator is to make the liquid form a thin film on the tube wall and heat and evaporate. Its working efficiency and operating characteristics largely depend on the uniform distribution of the liquid. This means that the liquid needs to be evenly distributed in each heat exchange tube and form a stable and uniform film on the tube wall. The rationality of the design of the liquid distribution device is crucial to the uniform distribution of the liquid. Uneven distribution will cause some areas to dry, while some areas may cause the film to be too thick due to excessive flow, affecting the heat exchange efficiency; too small flow may cause drying. Therefore, the design of the distributor has a direct impact on the thermal efficiency and operating stability of the evaporator, which in turn affects the production efficiency, product quality and service life of the equipment.

[0006] An ideal liquid distributor should be insensitive to changes in liquid layer height, evenly distribute liquid, form stable films, have greater operational flexibility, low pressure loss, and be less prone to clogging. However, once a traditional falling film evaporator is designed and manufactured, its film flow rate is usually fixed and needs to be shut down and disassembled for adjustment, which makes online adjustment impossible. Therefore, it cannot meet the above ideal characteristics. Summary of the invention

[0007] In order to overcome the shortcomings of the prior art, the present invention provides an intelligent liquid distribution device for a falling film evaporator and a method of using the same, so that the film can be evenly distributed regardless of whether the liquid supplied to the liquid distributor is stable. Secondly, the liquid distribution flow rate can be intelligently adjusted, and steam preheating can be effectively utilized while avoiding uneven film distribution caused by the influence of steam.

[0008] The technical solution of the present invention is as follows:

[0009] An intelligent liquid distribution device for a falling film evaporator comprises a shell and a feed pipe, a primary liquid distribution unit, a booster unit, an intelligent liquid distribution unit, a tube array and a discharge pipe arranged in sequence from top to bottom in the shell;

[0010] The feed pipe is connected to the primary liquid distribution unit, the primary liquid distribution unit is connected to the booster unit, the booster unit is connected to the intelligent liquid distribution unit, the intelligent liquid distribution unit distributes the liquid to the array tubes, and the array tubes are connected to the discharge pipe.

[0011] As a preferred technical solution of the present invention, the primary liquid distribution unit includes a liquid distribution tray and a plurality of liquid lower ports arranged at the bottom of the liquid distribution tray. The liquid distribution tray receives liquid from the feed pipe, and the liquid flows to the boosting unit through the plurality of liquid lower ports.

[0012] As a preferred technical solution of the present invention, the boosting unit includes a reducer and a boosting pump, the large opening at the upper part of the reducer is connected to the corresponding lower liquid opening on the liquid distribution tray, and the small opening at the lower part of the reducer is connected to the boosting pump.

[0013] Furthermore, the booster pump adopts a variable frequency pump to achieve the function of controlling the number of revolutions to adjust the flow rate and pressure.

[0014] As a preferred technical solution of the present invention, the intelligent liquid distribution unit comprises a liquid storage tray and a plurality of liquid distribution pipes connected to the liquid storage tray, and each liquid distribution pipe is sequentially provided with a regulating valve, a flow meter and a matching port;

[0015] The liquid storage tray is used to store the high-pressure flow from the booster pump, and the matching port is connected to the tube array.

[0016] As a preferred technical solution of the present invention, the regulating valve adopts PID control to adjust the valve opening of the regulating valve according to the flow rate of the flow meter; when the flow meter indicates too large, the regulating valve reduces the valve opening, and when the flow meter indicates too small, the regulating valve increases the valve opening, thereby ensuring that the liquid distribution pipe is filled with liquid.

[0017] As a preferred technical solution of the present invention, each matching port is connected to several falling film reboiler tube ports in the tube array.

[0018] The method for using the intelligent liquid dispensing device comprises the following steps:

[0019] S1. In the primary liquid distribution unit, the liquid distribution plate receives the liquid from the front system through the feed pipe, forms a certain liquid level on the liquid distribution plate, and the liquid goes to the corresponding booster unit through several lower liquid ports;

[0020] S2, in the booster unit, the liquid enters the booster pump through the reducer, and the liquid is pressurized by the booster pump and transported to the intelligent liquid distribution unit;

[0021] In S3 and the intelligent liquid distribution unit, high-pressure liquid enters the liquid storage tray, and the regulating valve is controlled by PID. The valve opening is adjusted according to the flow rate of the flow meter to ensure that the liquid distribution pipe is filled with liquid; finally, the liquid flows to the tube array through the matching port.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. The present invention provides a primary liquid distribution unit and a pressure boosting unit, so that the liquid distribution plate does not need to be completely level; secondly, the pressure boosting unit ensures uniform distribution of the liquid and also allows a larger liquid flow adjustment range.

[0024] 2. The present invention can adjust the liquid film flow in the evaporating tube online through the primary liquid distribution unit, the boosting unit and the intelligent liquid distribution unit. On the one hand, it is conducive to adapting to the change of flow. On the other hand, when the film formation flow in the evaporating tube does not meet the requirements, it can be adjusted online without stopping the machine and disassembling it. The operation of the evaporator is continuous. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative labor.

[0026] Figure 1 The present invention is a schematic diagram of the overall structure of an intelligent liquid distribution device for a falling film evaporator according to an embodiment of the present invention.

[0027] Figure 2 It is a partial schematic diagram of the primary liquid distribution unit, the booster unit and the intelligent liquid distribution unit in an embodiment of the present invention.

[0028] Figure 3 It is an overall schematic diagram of the primary liquid distribution unit, the booster unit and the intelligent liquid distribution unit in an embodiment of the present invention.

[0029] In the figure: 1. feed pipe; 2. shell; 31. liquid distribution tray; 32. lower liquid port; 33. reducer; 34. booster pump; 35. liquid storage tray; 36. liquid distribution pipe; 37. regulating valve; 38. flow meter; 39. matching port; 4. tube array; 5. discharge pipe. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] It should be noted that, in the absence of conflict, the features in the following embodiments and implementations may be combined with each other.

[0032] like Figures 1 to 3 As shown, an intelligent liquid distribution device for a falling film evaporator includes a feed pipe 1, a shell 2, a tube array 4, a discharge pipe 5, a primary liquid distribution unit, a booster unit and an intelligent liquid distribution unit.

[0033] The feed pipe 1 is connected to the primary liquid distribution unit, the primary liquid distribution unit is connected to the booster unit, the booster unit is connected to the intelligent liquid distribution unit, the intelligent liquid distribution unit distributes the liquid to the array tubes 4, and the array tubes 4 are connected to the discharge pipe 5. The feed pipe 1, the array tubes 4, the discharge pipe 5, the primary liquid distribution unit, the booster unit and the intelligent liquid distribution unit are contained in the housing 2.

[0034] The primary liquid distribution unit is designed with a liquid distribution pan 31 , and a plurality of liquid lowering ports 32 are designed at the bottom of the liquid distribution pan. The liquid distribution pan 31 can receive liquid from the front system, and the liquid can flow to the liquid lowering ports 32 .

[0035] The booster unit is designed with a reducer 33 and a booster pump 34. The reducer 33 has a large opening connected to the liquid distribution tray 31 and a small opening connected to the booster pump 34. The booster pump 34 can deliver liquid and boost pressure. The booster pump 34 uses a variable frequency pump, which can control the number of revolutions to adjust the flow and pressure.

[0036] The intelligent liquid distribution unit is designed with a liquid storage tray 35 , and a plurality of liquid distribution pipes 36 are distributed on the liquid storage tray 35 . The liquid distribution pipes 36 are connected to a regulating valve 37 , a flow meter 38 and a matching port 39 .

[0037] The liquid storage pan 35 can store the high-pressure flow from the booster pump 34 .

[0038] The regulating valve 37 can adjust the valve opening according to the flow rate of the flow meter 38. When the flow meter 38 indicates too large a flow rate, the regulating valve 37 reduces the valve opening. When the flow meter 38 indicates too small a flow rate, the regulating valve 37 increases the valve opening, so as to ensure that the liquid distribution pipe 36 is filled with liquid.

[0039] The matching port 39 is connected to the tube array of the falling film reboiler, and one matching port can be connected to several tube ports of the falling film reboiler.

[0040] The method for using the intelligent liquid dispensing device comprises the following steps:

[0041] S1, in the primary liquid distribution unit, the liquid distribution pan 31 receives the liquid from the front system through the feed pipe 1, a certain liquid level is formed on the liquid distribution pan 1, and the liquid goes to the corresponding booster unit through several lower liquid ports 32;

[0042] S2, in the boosting unit, the liquid enters the boosting pump 34 through the reducer 3, and the liquid is pressurized by the boosting pump 34 and transported to the intelligent liquid distribution unit;

[0043] S3, in the intelligent liquid distribution unit, high-pressure liquid enters the liquid storage tray 35, and the regulating valve 37 adopts PID control to adjust the valve opening according to the flow rate of the flow meter 38 to ensure that the liquid distribution pipe 36 is filled with liquid; finally, the liquid flows to the tube array 4 through the matching port 36.

[0044] The present invention provides a primary liquid distribution unit and a pressure boosting unit, so that the liquid distribution plate does not need to be completely level; secondly, the pressure boosting unit ensures uniform distribution of the liquid and also enables a larger liquid flow regulation range.

[0045] The present invention can adjust the liquid film flow in the evaporating tube online through the primary liquid distribution unit, the boosting unit and the intelligent liquid distribution unit. On the one hand, it is conducive to adapting to the change of flow. On the other hand, when the film forming flow in the evaporating tube does not meet the requirements, it can be adjusted online without stopping the machine and disassembling it. The operation of the evaporator is continuous.

[0046] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above implementation regulations. The above implementation regulations and descriptions are only preferred examples of the present invention and are not used to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. An intelligent liquid distribution device for a falling film evaporator, characterized in that: It comprises a housing (2) and a feed pipe (1), a primary liquid distribution unit, a pressurizing unit, an intelligent liquid distribution unit, a tube array (4) and a discharge pipe (5) which are arranged in sequence from top to bottom in the housing (2); The feed pipe (1) is connected to the primary liquid distribution unit, the primary liquid distribution unit is connected to the booster unit, the booster unit is connected to the intelligent liquid distribution unit, the intelligent liquid distribution unit distributes the liquid to the array tubes (4), and the array tubes (4) are connected to the discharge pipe (5).

2. The intelligent liquid distribution device for falling film evaporator according to claim 1, characterized in that: The primary liquid distribution unit comprises a liquid distribution tray (31) and a plurality of liquid lower openings (32) arranged at the bottom of the liquid distribution tray (31); the liquid distribution tray (31) receives liquid from the feed pipe (1); and the liquid flows to the boosting unit through the plurality of liquid lower openings (32).

3. The intelligent liquid distribution device for falling film evaporator according to claim 2, characterized in that: The boosting unit comprises a reducer (33) and a boosting pump (34); the large opening at the upper portion of the reducer (33) is connected to the corresponding lower liquid opening (32) on the liquid distribution tray (31); and the small opening at the lower portion of the reducer (33) is connected to the boosting pump (34).

4. The intelligent liquid distribution device for falling film evaporator according to claim 3, characterized in that: The booster pump (34) is a variable frequency pump to achieve the function of controlling the number of revolutions to adjust the flow rate and pressure.

5. The intelligent liquid distribution device for falling film evaporator according to claim 3, characterized in that: The intelligent liquid distribution unit comprises a liquid storage tray (35) and a plurality of liquid distribution pipes (36) connected to the liquid storage tray (35), and each liquid distribution pipe (36) is sequentially provided with a regulating valve (37), a flow meter (38) and a matching port (39); The liquid storage pan (35) is used to store the high-pressure flow from the booster pump (34), and the matching port (39) is connected to the tube array (4).

6. The intelligent liquid distribution device for falling film evaporator according to claim 5, characterized in that: The regulating valve (37) is controlled by PID, and the valve opening of the regulating valve (37) is adjusted according to the flow rate of the flow meter (38); when the flow meter (38) indicates too large a flow rate, the regulating valve (37) reduces the valve opening; when the flow meter (38) indicates too small a flow rate, the regulating valve (37) increases the valve opening, thereby ensuring that the liquid distribution pipe (36) is filled with liquid.

7. The intelligent liquid distribution device for falling film evaporator according to claim 5, characterized in that: Each matching port (39) is connected to a plurality of falling film reboiler tube ports in the tube array (4).

8. The method for using the intelligent liquid dispensing device according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1, in the primary liquid distribution unit, the liquid distribution plate (31) receives liquid from the front system through the feed pipe (1), a liquid level of a certain height is formed on the liquid distribution plate (1), and the liquid flows to the corresponding booster unit through a plurality of lower liquid ports (32); S2, in the boosting unit, the liquid enters the boosting pump (34) through the reducer (3), and the liquid is pressurized by the boosting pump (34) and transported to the intelligent liquid distribution unit; S3, in the intelligent liquid distribution unit, high-pressure liquid enters the liquid storage tray (35), and the regulating valve (37) is controlled by PID, and the valve opening is adjusted according to the flow rate of the flow meter (38) to ensure that the liquid distribution pipe (36) is filled with liquid; finally, the liquid flows to the tube array (4) through the matching port (36).

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