Multi-effect tubular falling film evaporation device

Abstract

The utility model relates to a multi-effect tubular falling film evaporation device which comprises a plurality of tubular falling film evaporators which are sequentially connected in series, a dead steam outlet is connected with one end of a dead steam pipe, and a gas outlet is connected with the dead steam pipe through a pipeline; an air inlet of the first-effect tubular falling-film evaporator is connected with a steam pipe, the other end of a steam exhaust pipe of the first-effect tubular falling-film evaporator is connected with an air inlet of the second-effect tubular falling-film evaporator, and so on, the other end of a steam exhaust pipe of the last-effect tubular falling-film evaporator is connected with a water cooler. The air outlet of the heat exchange cavity is connected with the steam exhaust pipe through the pipeline, so that steam exhausted from the heat exchange cavity directly enters the heat exchange cavity of the next-effect evaporator without passing through the liquid distribution area, the steam is prevented from impacting feed liquid from top to bottom after entering the material distribution area, and uniform film distribution of the feed liquid is guaranteed; meanwhile, impact of steam on the heating pipe head is avoided, the service life of equipment is prolonged, and efficient and stable operation of the evaporator is ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of aluminum oxide production, in particular to a multi-effect tubular falling film evaporation device. Background Art

[0002] In alumina production, multi-effect vacuum evaporation units are the most widely used. Due to the different flow directions of steam and solution, a countercurrent process is generally adopted, and the evaporation unit uses a tubular falling-film evaporator. The falling-film method uses a circulating pump to transport the feed liquid to the top of the evaporator. Under the action of gravity, the feed liquid passes through a distributor and a film distributor, flowing evenly into the heating tube bundle in the heating chamber, forming a thin film and flowing downward. The steam outside the tube bundle continuously exchanges heat with the film, and the feed liquid and vaporized steam inside the tube bundle flow into the vapor-liquid separation chamber for separation.

[0003] In current multi-effect evaporators, the heat exchange chamber's outlet is typically connected to the liquid distribution area. Steam discharged from the heat exchange chamber flows through the gas chamber into the distribution area, then into the heating tubes, and finally into the vapor-liquid separation chamber, where it enters the next effect along with the exhaust steam from the separation chamber. Because the gas chamber pressure is greater than the liquid chamber pressure, steam entering the distribution area impacts the liquid from top to bottom, preventing even film distribution and causing uneven film distribution on the evaporator, impacting evaporation efficiency. Furthermore, this steam impact can cause corrosion on the heating tube heads, shortening the equipment's service life. Therefore, designing and developing a multi-effect evaporator with a rational steam discharge path is crucial. Utility Model Content

[0004] In response to the problem in the above-mentioned prior art that the steam exhaust path is unreasonable and affects the evaporation efficiency and equipment service life, the utility model provides a multi-effect evaporation device, which adjusts the steam exhaust path by changing the pipeline design.

[0005] To achieve the above purpose, the technical solution of the utility model is as follows:

[0006] A multi-effect tubular falling film evaporator device comprises a plurality of tubular falling film evaporators connected in series, wherein the first evaporator in the series is a first-effect tubular falling film evaporator, the second evaporator in the series is a second-effect tubular falling film evaporator, and the last evaporator in the series is a last-effect tubular falling film evaporator; a heat exchange chamber of the tubular falling film evaporator is provided with an air inlet and an air outlet, a vapor-liquid separation chamber of the tubular falling film evaporator is provided with an exhaust steam outlet, the exhaust steam outlet is connected to one end of an exhaust steam pipe, and the exhaust steam outlet is connected to the exhaust steam pipe through a pipeline; the air inlet of the first-effect tubular falling film evaporator is connected to a steam pipe, and the other end of the exhaust steam pipe of the first-effect tubular falling film evaporator is connected to the air inlet of the second-effect tubular falling film evaporator, and so on, and the other end of the exhaust steam pipe of the last-effect tubular falling film evaporator is connected to a water cooler.

[0007] Furthermore, the inner cavity of the tubular falling film evaporator is provided with an upper baffle and a lower baffle, the liquid distribution area is above the upper baffle, the heat exchange cavity is between the upper baffle and the lower baffle, and the vapor-liquid separation chamber is below the lower baffle.

[0008] Furthermore, a plurality of heat exchange tubes are provided in the heat exchange cavity.

[0009] Furthermore, the air inlet is arranged at the lower part of the heat exchange cavity, and the air outlet is arranged at the upper part of the heat exchange cavity.

[0010] Furthermore, it comprises 6 tubular falling film evaporators connected in series.

[0011] Compared with the prior art, the beneficial effects of the present invention are:

[0012] The utility model provides a multi-effect tubular falling film evaporator, in which the air outlet of the heat exchange chamber is connected to the exhaust steam pipe through a pipe, so that the steam discharged from the heat exchange chamber directly enters the heat exchange chamber of the next-effect evaporator without passing through the liquid distribution area, avoiding the impact of the steam on the liquid from top to bottom after entering the distribution area, ensuring uniform film distribution of the liquid; at the same time, avoiding the impact of steam on the heating tube head, extending the service life of the equipment, and ensuring the efficient and stable operation of the evaporator. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The following further describes the embodiments of the present invention with reference to the accompanying drawings, wherein:

[0014] Figure 1 A schematic structural diagram of an embodiment of a multi-effect tubular falling film evaporation device is shown;

[0015] Figure symbols: 1-liquid distribution area, 2-heat exchange chamber, 3-vapor-liquid separation chamber, 4-pipeline, 5-exhaust steam outlet, 6-exhaust steam pipe, → represents the steam flow direction. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below through specific embodiments in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0017] A multi-effect tubular falling film evaporator device comprises a plurality of tubular falling film evaporators connected in series, wherein the first evaporator in the series is a first-effect tubular falling film evaporator, the second evaporator in the series is a second-effect tubular falling film evaporator, and the last evaporator in the series is a last-effect tubular falling film evaporator; a heat exchange chamber 2 of the tubular falling film evaporator is provided with an air inlet and an air outlet, a vapor-liquid separation chamber 3 of the tubular falling film evaporator is provided with an exhaust steam outlet 5, the exhaust steam outlet 5 is connected to one end of an exhaust steam pipe 6, and the air outlet is connected to the exhaust steam pipe 6 through a pipeline 4; the air inlet of the first-effect tubular falling film evaporator is connected to a steam pipe, and the other end of the exhaust steam pipe 6 of the first-effect tubular falling film evaporator is connected to the air inlet of the second-effect tubular falling film evaporator, and so on, and the other end of the exhaust steam pipe 6 of the last-effect tubular falling film evaporator is connected to a water cooler.

[0018] In one embodiment of the present invention, the inner cavity of the tubular falling film evaporator is provided with an upper partition and a lower partition, above the upper partition is a liquid distribution area 1, between the upper and lower partitions is a heat exchange cavity 2, and below the lower partition is a vapor-liquid separation chamber 3.

[0019] In one embodiment of the present invention, a plurality of heat exchange tubes are provided in the heat exchange chamber 2 .

[0020] In one embodiment of the present invention, the air inlet is arranged at the lower part of the heat exchange chamber 2 , and the air outlet is arranged at the upper part of the heat exchange chamber 2 .

[0021] In one embodiment of the present invention, six tubular falling film evaporators are sequentially connected in series.

[0022] The steam flow route in the multi-effect tubular falling film evaporator is shown in the attached Figure 1 The feed liquid enters the vapor-liquid separation chamber after passing through the liquid distribution area 1 and the heat exchange chamber 2, and the separated exhaust steam enters the exhaust steam pipe 6 through the exhaust steam outlet 5; the steam after heat exchange in the heat exchange chamber 2 also enters the exhaust steam pipe 6 through the pipeline 4; the exhaust steam and the steam after heat exchange enter the heat exchange chamber 2 of the next effect evaporator through the exhaust steam pipe 6, and continue to exchange heat with the feed liquid in the next effect evaporator. The steam after heat exchange continues to enter the subsequent evaporator according to the above-mentioned gas flow method, until it is discharged into the water cooler through the exhaust steam pipe 6 in the last effect.

[0023] The utility model provides a multi-effect tubular falling film evaporator, in which the air outlet of the heat exchange chamber is connected to the exhaust steam pipe through a pipe, so that the steam discharged from the heat exchange chamber directly enters the heat exchange chamber of the next-effect evaporator without passing through the liquid distribution area, avoiding the impact of the steam on the liquid from top to bottom after entering the distribution area, ensuring uniform film distribution of the liquid; at the same time, avoiding the impact of steam on the heating tube head, extending the service life of the equipment, and ensuring the efficient and stable operation of the evaporator.

[0024] Some exemplary embodiments of the present invention are described above. It will be understood that the above embodiments are only used to explain the present invention and do not constitute a limitation on the scope of protection of the present invention. The features in these embodiments can be recombined in an appropriate manner, and the solutions obtained thereby are still within the scope of protection claimed by the present invention. Based on the above embodiments, all other embodiments obtained by those skilled in the art without making any creative work, that is, all modifications, equivalent substitutions and improvements made within the spirit and principles of this application, fall within the scope of protection claimed by the present invention.

Claims

1. A multi-effect tubular falling film evaporator, characterized in that: The invention comprises a plurality of tubular falling film evaporators connected in series, wherein the first evaporator in the series is a first-effect tubular falling film evaporator, the second evaporator in the series is a second-effect tubular falling film evaporator, and the last evaporator in the series is a last-effect tubular falling film evaporator; the heat exchange chamber (2) of the tubular falling film evaporator is provided with an air inlet and an air outlet, the vapor-liquid separation chamber (3) of the tubular falling film evaporator is provided with an exhaust steam outlet (5), the exhaust steam outlet (5) is connected to one end of an exhaust steam pipe (6), and the air outlet is connected to the exhaust steam pipe (6) through a pipe (4); the air inlet of the first-effect tubular falling film evaporator is connected to a steam pipe, and the other end of the exhaust steam pipe (6) of the first-effect tubular falling film evaporator is connected to the air inlet of the second-effect tubular falling film evaporator, and so on, and the other end of the exhaust steam pipe (6) of the last-effect tubular falling film evaporator is connected to a water cooler.

2. A multi-effect tubular falling film evaporator according to claim 1, characterized in that: The inner cavity of the tubular falling film evaporator is provided with an upper baffle and a lower baffle, a liquid distribution area (1) is located above the upper baffle, a heat exchange cavity (2) is located between the upper baffle and the lower baffle, and a vapor-liquid separation chamber (3) is located below the lower baffle.

3. A multi-effect tubular falling film evaporator according to claim 1 or 2, characterized in that: A plurality of heat exchange tubes are provided in the heat exchange cavity (2).

4. A multi-effect tubular falling film evaporator according to claim 1 or 2, characterized in that: The air inlet is arranged at the lower part of the heat exchange cavity (2), and the air outlet is arranged at the upper part of the heat exchange cavity (2).

5. The multi-effect tubular falling film evaporator according to claim 1, characterized in that: It includes 6 tubular falling film evaporators connected in series.

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