Falling film evaporation system for recovering dicarboxylic acid in adipic acid waste liquid

Abstract

The utility model discloses a falling film evaporation system for recovering dicarboxylic acid in adipic acid waste liquid, which comprises a first-stage rising film evaporator, a second-stage falling film evaporator, a third-stage rising film evaporator and a flaker, and the first-stage rising film evaporator, the second-stage falling film evaporator and the third-stage rising film evaporator are respectively provided with a medium circulation assembly. The first-stage climbing film evaporator, the second-stage falling film evaporator, the third-stage climbing film evaporator and the flaker are sequentially communicated through a main pipeline, and the return pipe is arranged between the steam output end of the second-stage falling film evaporator and the steam auxiliary inlet of the first-stage climbing film evaporator. A gas phase treated by the second-stage falling film evaporator can be guided into the medium bin of the first-stage rising film evaporator to serve as a heat exchange medium of the first-stage rising film evaporator, the temperature of the medium can be accurately controlled through the arranged temperature detector and the temperature control regulating valve, and feed liquid can be preheated in advance through the arranged preheater.

Description

Technical Field

[0001] The utility model relates to the technical field of chemical equipment, in particular to a falling film evaporation system for recovering dicarboxylic acid in adipic acid waste liquid. Background Art

[0002] Adipic acid is an important raw material for chemical production, and is widely used in the fields of organic synthesis, medicine, lubricant manufacturing, nylon 66 and engineering plastics. In the production process of adipic acid, a large amount of DBA waste liquid with dibasic acid as the main component (dibasic acid is mainly adipic acid, succinic acid, glutaric acid, and the rest is water and nitric acid) is produced as raw materials. As a by-product in the production process of adipic acid, dibasic acid has a high recycling value due to its high content (about 15-25%).

[0003] According to the Chinese patent document with the announcement number CN217409760U, a continuous evaporation system for recovering dibasic acid from adipic acid waste liquid is disclosed. The continuous evaporation system can better ensure the continuous and stable recovery of dibasic acid through the combined application of three-stage evaporators. Combined with the optimization of relevant process parameters, the preliminary results show that for adipic acid DBA waste liquid, the continuous and stable recovery of dibasic acid in the waste liquid can be achieved relatively stably, and the quality of the recovered material is relatively stable.

[0004] However, in the above device, the gas phase treated by the second rising film evaporator usually directly proceeds to the next process, and the high temperature contained in the gas phase itself is often wasted, which cannot achieve effective utilization of resources. At the same time, the input amount of the steam medium of the three evaporators cannot be accurately controlled, and the evaporation temperature is often too high or too low. Therefore, a falling film evaporation system for recovering dicarboxylic acid in adipic acid waste liquid is proposed. Utility Model Content

[0005] The utility model aims to provide a falling film evaporation system for recovering dicarboxylic acid in adipic acid waste liquid, so as to solve the problems raised in the above-mentioned background technology.

[0006] To achieve the above-mentioned purpose, the utility model provides the following technical scheme: a falling film evaporation system for recovering dicarboxylic acid in adipic acid waste liquid, comprising a first-stage rising film evaporator, a second-stage falling film evaporator, a third-stage rising film evaporator and a flaker, wherein the first-stage rising film evaporator, the second-stage falling film evaporator and the third-stage rising film evaporator are all provided with a medium circulation component, the first-stage rising film evaporator, the second-stage falling film evaporator, the third-stage rising film evaporator and the flaker are connected in sequence through a main pipeline, and a reflux pipe is provided between the steam output end of the second-stage falling film evaporator and the steam secondary inlet of the first-stage rising film evaporator.

[0007] As a further preferred embodiment of the present technical solution, a No. 1 separator and a No. 1 feed pump are sequentially arranged on the main pipeline between the first-stage rising film evaporator and the second-stage falling film evaporator.

[0008] As a further preferred embodiment of the present technical solution, a second feed pump is provided on the main pipeline between the secondary falling film evaporator and the tertiary rising film evaporator.

[0009] As a further preferred embodiment of the present technical solution, a No. 2 separator and a No. 3 feed pump are sequentially arranged on the main pipeline between the three-stage rising film evaporator and the flaker.

[0010] As a further preferred embodiment of the present technical solution, the medium circulation component includes a medium transmission pipe, and the first-stage rising film evaporator is respectively provided with a steam inlet and a condensed water outlet, and the steam inlet and the condensed water outlet are respectively connected to the medium transmission pipe.

[0011] As a further preferred embodiment of the present technical solution, a flow control mechanism acting on the medium is arranged on the medium circulation component, the flow control mechanism is composed of a temperature control regulating valve and a temperature detector, a temperature control regulating valve is arranged on the medium transmission pipe connected to the steam inlet, a temperature detector acting on the steam medium is arranged in the first-stage rising film evaporator, and the temperature detector is electrically connected to the temperature control regulating valve.

[0012] As a further preferred embodiment of the present technical solution, a preheater is provided at the feed liquid inlet end of the first-stage rising film evaporator.

[0013] The utility model provides a falling film evaporation system for recovering dicarboxylic acid in adipic acid waste liquid, which has the following beneficial effects:

[0014] The utility model arranges a reflux pipe between the steam output end of the secondary falling film evaporator and the steam auxiliary inlet of the primary rising film evaporator, so that the gas phase treated by the secondary falling film evaporator can be introduced into the medium bin of the primary rising film evaporator as the heat exchange medium of the primary rising film evaporator, thereby making full use of energy; the temperature of the medium can be accurately controlled by the arranged temperature detector and the temperature control regulating valve; the feed liquid can be preheated in advance by the arranged preheater, thereby improving the evaporation efficiency of the feed liquid after entering the primary rising film evaporator. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the overall structure of the utility model;

[0016] Figure 2 It is a three-dimensional schematic diagram of a part of the structure of the utility model;

[0017] Figure 3 It is a structural schematic diagram of a first-stage rising film evaporator and a second-stage falling film evaporator in the utility model;

[0018] Figure 4 It is a schematic diagram of the structure of the three-stage rising film evaporator and the flake forming machine in the utility model;

[0019] In the figure: 1. First-stage rising film evaporator; 2. Second-stage falling film evaporator; 3. Third-stage rising film evaporator; 4. Flaker; 5. Main pipeline; 6. No. 1 feed pump; 7. No. 2 feed pump; 8. No. 3 feed pump; 9. Preheater; 10. Temperature control valve; 11. Temperature detector; 12. Medium transmission pipe; 13. Reflux pipe; 14. No. 1 separator; 15. No. 2 separator. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0021] The utility model provides a technical solution: Figures 1 to 4 As shown, in this embodiment, a falling film evaporation system for recovering dicarboxylic acid in adipic acid waste liquid comprises a first-stage rising film evaporator 1, a second-stage falling film evaporator 2, a third-stage rising film evaporator 3 and a flake machine 4, the first-stage rising film evaporator 1, the second-stage falling film evaporator 2 and the third-stage rising film evaporator 3 are all provided with a medium flow component, the first-stage rising film evaporator 1, the second-stage falling film evaporator 2, the third-stage rising film evaporator 3 and the flake machine 4 are connected in sequence through a main pipeline 5, and a reflux pipe 13 is provided between the steam output end of the second-stage falling film evaporator 2 and the steam secondary inlet of the first-stage rising film evaporator 1.

[0022] Among them, a No. 1 separator 14 and a No. 1 feed pump 6 are arranged in sequence on the main pipeline 5 between the first-stage rising film evaporator 1 and the second-stage falling film evaporator 2, a No. 2 feed pump 7 is arranged on the main pipeline 5 between the second-stage falling film evaporator 2 and the third-stage rising film evaporator 3, and a No. 2 separator 15 and a No. 3 feed pump 8 are arranged in sequence on the main pipeline 5 between the third-stage rising film evaporator 3 and the flaker 4.

[0023] The diacid waste liquid will enter the first-stage falling film evaporator 1 through the liquid inlet at the bottom of the first-stage falling film evaporator 1, and the No. 1 separator 14 will separate the evaporated diacid waste liquid into gas phase and liquid phase. The gas phase will enter the subsequent process from the exhaust end of the No. 1 separator 14, and the liquid phase will enter the second-stage falling film evaporator 2 under the action of the No. 1 feed pump 6. The second-stage falling film evaporator 2 will evaporate the liquid phase again, and the evaporated liquid phase will enter the third-stage falling film evaporator 3 through the No. 2 feed pump 7. After being processed by the third-stage falling film evaporator 3, the No. 2 separator 15 will guide the separated liquid phase to the flaker 4, and the gas phase will be carried out in the subsequent process through the exhaust port of the No. 2 separator 15. The reflux pipe 13 arranged between the steam output end of the second-stage falling film evaporator 2 and the steam secondary inlet of the first-stage falling film evaporator 1 can introduce the gas phase processed by the second-stage falling film evaporator 2 into the medium bin of the first-stage falling film evaporator 1 as the heat exchange medium of the first-stage falling film evaporator 1, thereby making full use of energy.

[0024] Among them, the medium circulation component includes a medium transmission pipe 12, and a steam inlet and a condensed water outlet are respectively opened on the first-stage rising film evaporator 1 (the first-stage rising film evaporator 1 is taken as an example for description here, and the medium circulation component structure on the second-stage falling film evaporator 2 and the third-stage rising film evaporator 3 is the same), and the steam inlet and the condensed water outlet are respectively connected with a medium transmission pipe 12.

[0025] Steam is introduced into the first-stage rising film evaporator 1 through the medium transmission pipe 12, and the steam can heat the feed liquid. The condensed water after the steam is cooled will be discharged through the condensed water outlet.

[0026] Among them, a flow control mechanism acting on the medium is arranged on the medium circulation component, and the flow control mechanism is composed of a temperature control regulating valve 10 and a temperature detector 11. The temperature control regulating valve 10 is arranged on the medium transmission pipe 12 connected to the steam inlet, and a temperature detector 11 acting on the steam medium is arranged in the first-stage rising film evaporator 1 (herein, the first-stage rising film evaporator 1 is taken as an example for description, and the flow control mechanism structure on the second-stage falling film evaporator 2 and the third-stage rising film evaporator 3 is the same), and the temperature detector 11 is electrically connected to the temperature control regulating valve 10.

[0027] The temperature of the steam medium can be detected by the set temperature detector 11. When the temperature is too high, the temperature control valve 10 electrically connected to the temperature detector 11 will automatically reduce the input of the steam medium, otherwise it will increase the input of the steam medium, thereby accurately controlling the temperature of the medium.

[0028] Wherein, a preheater 9 is provided at the liquid inlet end of the first-stage rising film evaporator 1 .

[0029] The preheater 9 can be used to preheat the feed liquid in advance, thereby improving the evaporation efficiency of the feed liquid after entering the first-stage rising film evaporator 1.

[0030] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A falling film evaporation system for recovering dicarboxylic acid from adipic acid waste liquid, comprising a first-stage rising film evaporator (1), a second-stage falling film evaporator (2), a third-stage rising film evaporator (3) and a flaker (4), characterized in that: The first-stage rising film evaporator (1), the second-stage falling film evaporator (2) and the third-stage rising film evaporator (3) are all provided with a medium circulation component; the first-stage rising film evaporator (1), the second-stage falling film evaporator (2), the third-stage rising film evaporator (3) and the flake forming machine (4) are sequentially connected through a main pipeline (5); a reflux pipe (13) is provided between the steam output end of the second-stage falling film evaporator (2) and the steam secondary inlet of the first-stage rising film evaporator (1).

2. A falling film evaporation system for recovering dicarboxylic acid from adipic acid waste liquid according to claim 1, characterized in that: A No. 1 separator (14) and a No. 1 feed pump (6) are sequentially arranged on the main pipeline (5) between the first-stage rising film evaporator (1) and the second-stage falling film evaporator (2).

3. The falling film evaporation system for recovering dicarboxylic acid from adipic acid waste liquid according to claim 1, characterized in that: A second feed pump (7) is provided on the main pipeline (5) between the second-stage falling film evaporator (2) and the third-stage rising film evaporator (3).

4. The falling film evaporation system for recovering dicarboxylic acid from adipic acid waste liquid according to claim 1, characterized in that: A No. 2 separator (15) and a No. 3 feed pump (8) are sequentially arranged on the main pipeline (5) between the three-stage rising film evaporator (3) and the flaker (4).

5. The falling film evaporation system for recovering dicarboxylic acid from adipic acid waste liquid according to claim 1, characterized in that: The medium circulation component comprises a medium transmission pipe (12), and the first-stage rising film evaporator (1) is respectively provided with a steam inlet and a condensed water outlet, and the steam inlet and the condensed water outlet are respectively connected to the medium transmission pipe (12).

6. A falling film evaporation system for recovering dicarboxylic acid from adipic acid waste liquid according to claim 5, characterized in that: A flow control mechanism acting on the medium is arranged on the medium circulation component, the flow control mechanism is composed of a temperature control regulating valve (10) and a temperature detector (11), the temperature control regulating valve (10) is arranged on the medium transmission pipe (12) connected to the steam inlet, the temperature detector (11) acting on the steam medium is arranged in the first-stage rising film evaporator (1), and the temperature detector (11) is electrically connected to the temperature control regulating valve (10).

7. The falling film evaporation system for recovering dicarboxylic acid from adipic acid waste liquid according to claim 1, characterized in that: A preheater (9) is provided at the liquid inlet end of the first-stage rising film evaporator (1).

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